DIP PROCESS Khanna paper

PROCESS DESCRIPTION

KHANNANEW DIP LINE 300 BDMT/24h

PRINTING - WRITING

DPT : SAD Par/by : JLB Date : 25/08/04

Client / Customer code : 03047 Rev. Page

Command / Order ref. : 0401010 PD 0155A 00 1 / 264

39, rue de la Fontaine Ludot – BP 46 – 51302 Vitry-le-François Cedex – FranceTel.: +33 (0)3.26.74.80.80 – Fax: +33 (0)3.26.72.08.33 – www.kadant.com

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PD0155 A 00 - JLB FIRST ISSUE23/09/2004

1 REVISIONS TO DOCUMENT 9

2 GENERAL 10

2.1 GENERAL DESCRIPTION.............................................................................................................10

2.2 SCOPE............................................................................................................................................10

2.3 DE-INKED PULP PRODUCTION SET-POINTS.............................................................................11

2.3.1 Control Principle.................................................................................................................11

2.3.2 Interlocks & Production Set-Points ....................................................................................13

2.3.3 Production Flexibility, Quality Control & Pulp Production ..................................................13

2.3.4 Ash control and Yield control in Pulp Production................................................................15

2.4 DIP LINE WATER BALANCE & CONTROLS.................................................................................16

2.4.1 Loop 1 Filtrate balance controls.........................................................................................16



3 PULPING 21

3.1 DESCRIPTION................................................................................................................................21

3.1.1 Pulping itemization..............................................................................................................21

3.1.2 Helico Pulper basics...........................................................................................................22

3.1.3 Dumping Poire basics.........................................................................................................23

3.1.4 Pulping area........................................................................................................................25

3.2 BASIC OPERATING CAPACITY....................................................................................................30

3.3 TRANSMITTERS and CONTROL LOOPS.....................................................................................31

3.3.1 Pulping area 1.....................................................................................................................31

3.3.2 Pulping area 2.....................................................................................................................32

3.3.3 Common to both Pulper areas............................................................................................32

3.4 INTERLOCKINGS AND ALARMS..................................................................................................33

3.4.1 Pulping area 1.....................................................................................................................33

3.4.2 Pulping area 2.....................................................................................................................35

3.4.3 Common to both Pulper areas............................................................................................38

3.5 OPERATION...................................................................................................................................40

3.5.1 Start-up 40

3.5.2 Operation 43

3.5.3 Stop 43

4 HD CLEANING AND HOLE SCREENING 45

4.1 DESCRIPTION ...............................................................................................................................45

4.1.1 HD Cleaning and Holes screening Itemization...................................................................45

GENERALPage 2/264


4.1.2 High Density Cleaner basics...............................................................................................46

4.1.3 Horizontal screen (CH) basics............................................................................................47

4.1.4 Tailing screen Diabolo........................................................................................................50

4.1.5 HD Cleaning and Holes Screening Area ...........................................................................53




4.5 OPERATION...................................................................................................................................65

4.5.1 Start-up 65

4.5.2 Production 66

4.5.3 Operation 66

4.5.4 Stop 67

5 SLOTS PRE-SCREENING69

5.1 DESCRIPTION................................................................................................................................69

5.1.1 Area itemization..................................................................................................................69

5.1.2 ScreenOne basics..............................................................................................................69

5.1.3 Slots Pre-screening area....................................................................................................71

5.2 BASIC OPERATION CAPACITY....................................................................................................73

5.3 TRANSMITTERS AND CONTROL LOOPS...................................................................................73


5.5 OPERATION...................................................................................................................................78

5.5.1 Start-up 78

5.5.2 Operation 79

5.5.3 Sequences 80

5.5.4 Shutdown 82

6 PRIMARY FLOTATION 84

6.1 DESCRIPTION ...............................................................................................................................84

6.1.1 Flotation Itemization............................................................................................................84

6.1.2 Flotation cell (MAC) basics.................................................................................................85

6.1.3 Deinking MAC cell multi-Aeration flotation ........................................................................87

6.1.4 Deinking cell MAC Sequence.............................................................................................87

6.1.5 Pre-Flotation area...............................................................................................................88



6.3.1 Prime MAC 03CEV02a.......................................................................................................93

6.3.2 Primary flotation cell MAC 03CEV02b................................................................................94

GENERALPage 3/264



6.5 OPERATION...................................................................................................................................99

6.5.1 Start up 99

6.5.2 Operation 101

6.5.3 Stop 102

7 CLEANING 106

7.1 DESCRIPTION..............................................................................................................................106

7.1.1 Area Itemization................................................................................................................106

7.1.2 Basics Cleaners System...................................................................................................106

7.1.3 Cleaners system sequence..............................................................................................108

7.1.4 Area description................................................................................................................109

7.2 BASIC OPERATING CAPACITY..................................................................................................113

7.3 TRANSMITTERS AND CONTROL LOOPS.................................................................................113

7.4 INTERLOCKINGS AND ALARMS................................................................................................115

7.5 OPERATION.................................................................................................................................119

7.5.1 Start-Up 119

7.5.2 Operation 121

7.5.3 Shutdown 121

8 LOOP 1 DISC FILTER & WATER DISTRIBUTION 124

8.1 DESCRIPTION..............................................................................................................................124

8.1.1 Area itemization................................................................................................................124

8.1.2 Disc Filter basics...............................................................................................................124

8.1.3 Area description................................................................................................................129




8.4.1 Loop 1 Disc Filter 05FDQ01.............................................................................................132

8.4.2 Loop 1 water distribution...................................................................................................133

8.5 OPERATION.................................................................................................................................136

8.5.1 Start-up 136

8.5.2 Operation 138

8.5.3 Shutdown 139

9 LOOP1 THICKENING, KNEADING AND OXYDATIVE BLEACHING AREA 141

9.1 DESCRIPTION .............................................................................................................................141

9.1.1 Area Itemization................................................................................................................141

GENERALPage 4/264


9.1.2 MC Pump basics...............................................................................................................141

9.1.3 Screw Press basics..........................................................................................................141

9.1.4 Basics Kneader type TL ...................................................................................................142

9.1.5 Basics Pollcon Tower.......................................................................................................143

9.1.6 Dispersion and Bleaching description..............................................................................146




9.4.1 Transfer MC pump 05PMC10...........................................................................................153

9.4.2 Recirculation chest 07CPA11...........................................................................................154

9.4.3 Screw Press 06PVS01.....................................................................................................156

9.4.4 Kneader 06TL02...............................................................................................................156

9.4.5 0xidative bleaching tower 07CPA01.................................................................................158

9.4.6 ALARMS 163

9.5 OPERATION.................................................................................................................................164

9.5.1 Start-up 164

9.5.2 Operation 165

9.5.3 Shutdown 166

10 FINE SCREENING 168

10.1 DESCRIPTION...........................................................................................................................168

10.1.1 Area itemization..............................................................................................................168

10.1.2 ScreenOne basics..........................................................................................................168

10.1.3 Fine screening area........................................................................................................169

10.2 BASIC OPERATION CAPACITY................................................................................................171

10.3 TRANSMITTERS AND CONTROL LOOPS...............................................................................171

10.4 INTERLOCKINGS AND ALARMS..............................................................................................174

10.5 OPERATION...............................................................................................................................176

10.5.1 Start-up 176

10.5.2 Operation 177

10.5.3 Sequences......................................................................................................................178

10.5.4 Shutdown 180

11 POST-FLOTATION 182

11.1 DESCRIPTION ..........................................................................................................................182

11.1.1 Post-Flotation Itemization...............................................................................................182

11.1.2 Flotation cell (MAC) basics.............................................................................................182

11.1.3 Deinking cell MAC Sequence.........................................................................................182

11.1.4 Post-Flotation area.........................................................................................................183

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11.2 BASIC OPERATING CAPACITY................................................................................................186

11.3 TRANSMITTERS and CONTROL LOOPS.................................................................................186


11.5 OPERATION...............................................................................................................................190

11.5.1 Start up 190


11.5.3 Stop 192

12 LOOP 2 DISC FILTER & WATER DISTRIBUTION 195

12.1 DESCRIPTION...........................................................................................................................195

12.1.1 Area itemization..............................................................................................................195

12.1.2 Disc Filter basics.............................................................................................................195

12.1.3 Area description.............................................................................................................196




12.4.1 Desaeration chest 10CPA01..........................................................................................200

12.4.2 Loop 2 Disc Filter 10FDQ04...........................................................................................201

12.4.3 Loop 2 water distribution.................................................................................................202

12.5 OPERATION...............................................................................................................................206

12.5.1 Start-up 206


12.5.3 Shutdown 208

13 REDUCTIVE BLEACHING 210

13.1 DESCRIPTION...........................................................................................................................210

13.1.1 Reductive bleaching itemization.....................................................................................210

13.1.2 Heating screw.................................................................................................................210

13.1.3 MC Pump basics.............................................................................................................210

13.1.4 Reductive bleaching description.....................................................................................211

13.2 BASIC OPERATION CAPACITY................................................................................................213



13.5 OPERATION...............................................................................................................................217

13.5.1 Start-up 217


13.5.3 Shutdown 219

GENERALPage 6/264


14 LOOP 2 DISPERSING SYSTEM 221

14.1 DESCRIPTION ..........................................................................................................................221

14.1.1 Area Itemization..............................................................................................................221

14.1.2 Dispersing system..........................................................................................................221

14.1.3 Area description..............................................................................................................222




14.4.1 Dispersing system..........................................................................................................232

14.4.2 Storage tower 12CPA03.................................................................................................236

14.5 OPERATION...............................................................................................................................239

14.5.1 Start-up 239


14.5.3 Shutdown 241

15 WASHING & FINAL STORAGE 244

15.1 DESCRIPTION...........................................................................................................................244

15.1.1 Area Itemization..............................................................................................................244

15.1.2 Washer basics................................................................................................................245

15.1.3 DNT Washer operation...................................................................................................246





15.4.1 Transfer chest 12CPA06................................................................................................255

15.4.2 Washers feed pump 13PPC01.......................................................................................256

15.4.3 Washer 13LAV02............................................................................................................257

15.4.4 Washer 13LAV03............................................................................................................259

15.4.5 Common to both Washers..............................................................................................262

15.4.6 Transfer MC pump 14PMC11.........................................................................................263

15.4.7 Storage tower 14CPA04.................................................................................................265

15.5 OPERATION...............................................................................................................................267

15.5.1 Start-up 267


15.5.3 Shutdown 270

16 LOOP 3 WATER DISTRIBUTION & MICRO-FLOTATION 273

16.1 DESCRIPTION...........................................................................................................................273

16.1.1 Itemization......................................................................................................................273

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16.1.2 Microflotator PPM basics................................................................................................274





16.5 OPERATION...............................................................................................................................286

16.5.1 Start-up 286


16.5.3 Shutdown 287

GENERALPage 8/264


1 REVISIONS TO DOCUMENT

Rev Date Author Description/pages modified

00 23/0904 JLV 1st ISSUE.

GENERALPage 9/264


2 GENERAL

NB: General remarks for all sequence timers.All timers noted “operator screen “have to be adjusted by operator.All the others need (for process reasons) to be adjustable but with a different ac-cess level.

1.1 GENERAL DESCRIPTION

The new KHANNA DIP line comprises the installation of a 3 loops deinking pulp line complete from waste paper to pulp storage, including variable washing - deashing and DIP water processes.

The deinking grade produce is PRINTING/WRITING made with deinking pulp from this line and from an existing modified line.

The capacity of this deinking line is 300 BDMT/24h into the storage.

This document is to serve as basis for the program of the DCS control software, a guide for operation of the line and training of the operators.

The area considered here is fully controlled from by a Distributed Control System (DCS), with local controls for a limited number of applications, for regulations, in-terlocks, sequences and group-start/group-stop.

1.2 SCOPE

We review in this document the global process layout and main control paramet-ers.

Chemical Storage and distribution, Sludge Thickening, Paper Machine systems are excluded from the scope of this document.

For each area, the process is outlined with a definition of the main sub-systems, basic operating data and main control relations to other process areas.

All items used hereafter (for equipment, valves and instrumentation) correspond to Flow-Sheet N° FS5232.

GENERALPage 10/264


1.3 DE-INKED PULP PRODUCTION SET-POINTS

1.3.1 Control Principle

The object of the Line production control will be to maintain all intermediate pulp storage volumes stable (Dump Chest, Bleaching Towers) and maintain Storage Tower at required level.

Differences in actual tonnage processed in the different loops, resulting either from instrument error or process variation, are corrected by operator following the evolutions of the levels in the intermediate capacities

The operator determines the production set points for the line as described here-under.

1.3.1.1 Waste Paper Pulping tonnage

Pulper system takes water from Pulper Water Tank 05CE11 and dumps stock into Pulper Dump Chest 01CPA15.

The Pulper production follows the level in Pulper Dump Chest 01CPA15.

1.3.1.2 Loop 1 production control P1-3015

Loop 1 takes pulp from Pulper Dump Chest 01CPA15 and delivers Pulp to Loop 1 Bleaching Tower 07CPA01 - with water recirculating from Loop 1 Disc Filter & Screw-press to Loop 1 Water tanks.

Loop 1 Pre-screening Slots production is set as set-point to P1-3015.

As transmitter NT3015 continuously measures the consistency of this flow, flow in m3/h can be calculated and adjusted automatically through Flowmeter FIC3020.

Pre-Screen slots 02SC19 accept flow is forwarded from Constant level box 02CP20.Then the flow accepted from Stage 1 Pre-Screen slots 02SC19, in excess from the flow controlled by FIC3020, flows back to Slots screening Feed Chest 02CPA16. The operation of ScreenOne is not affected by changes in throughput.

The Loop 1 Pre-screening accept tonnage is adjusted by checking Loop 1 Bleaching Tower 07CPA01 level LIS6070.

In practice, the residence time of 2 hours in the Loop 1 Pollcon Tower operated at 80% level with an average 25-35% consistency, leaves time to avoid overflow-ing or emptying the Tower.

Operation with stable Bleaching Tower level is recommended for stable Bleach-ing operation.

GENERALPage 11/264



Loop 2 takes pulp from Loop 1 Bleaching Tower 07CPA01 and delivers pulp to Loop 2 Storage Tower 12CPA03 - with water recirculating from Loop 2 Disc Filter & Screw-press to Loop 2 Water tanks.

Loop 2 Production is adjusted with Flowmeter FIC8010 on post-flotation stock feed pipe.

This adjustment has a direct repercussion on Loop 2 screening feed chest 07CPA08 level control LIC6120 with valve LCV-6120 regulating delivery flow from Bleaching tower 07CPA01 extraction pump 07PPC07.

Then Loop 2 production P2-5070 is calculated from Flowmeter FI6115 (bleaching tower 07CPA01 extracted flow) and consistency controller NRC6095.

Operator must check and correct Flowmeter FIC8010 set-point in order to keep constant level in Bleaching Tower 07CPA01.

In order to keep constant Storage tower 12CPA03 level LIS11045, Loop 2 ton-nage P2-5070 should vary relatively to Deashing system throughput P3-12005 and to Final Storage tower 14CPA04 level LIS15040 (when DNT washers are by-passed).


Loop 3 takes pulp from Loop 2 Storage Tower 12CPA03 and delivers pulp to Storage Tower 14CPA04 - with water recirculating from Loop 3 DNT Washers to Loop 3 Water tanks.

Deashing stock feed production is set as set-point to P3-12005.As the consistency of this flow is continuously measured & controlled by regula-tion loop NIC11075, set flow in m3/h can be calculated and adjusted automatically through Flowmeter FIC12005.

Moreover a washing by-pass line allows to transfer pulp from Storage Tower 12CPA03 directly to Storage Tower 14CPA04 via extraction pump 12PPC05.Consistency at this point is continuously measured by regulation loop NIC11050, set flow in m3/h can then be calculated and adjusted automatically through Flow-meter FIC15095.

Total stock production required from Loop 2 is the sum of Washing feed produc-tion and washing by-pass production.

The Loop 3 Production control P3-12005 and washing by-pass quantity can be adjusted by checking Storage tower 14CPA04 level LIS15040 and Loop 2 Bleaching tower 12CPA03 level LIS11045.

Operation with stable Storage Tower level is recommended for stable water bal-ance.

GENERALPage 12/264


1.3.1.5 Pulp from Storage to Paper Machine

Paper Machine area Controller adjusts the remote set-point of FIC-15060 con-trolling extracted flow from Storage Tower 14CPA04.

This transfer production is calculated through Flowmeter FIC15060 and consist-ency controller NRC15045.

1.3.2 Interlocks & Production Set-Points

Operation of the process equipment will prevail on production control through control interlocks to maintain continuity of operations on the line.

These interlocks are detailed in the applicable paragraph for each process area.

However Operators are required to check all Pulp Bleaching and Storage Towers level trends regularly in operation and to adjust Production set-points accordingly.

Note: for all systems operated at a stable hydraulic load (flotation cells, cleaners), no interlocks protect against operation in sub-optimal conditions, if a pulp flow is applied superior to the design capacity.

Setting a production flow above the design values may lead to sub-optimal per-formances or production disruption.

1.3.3 Production Flexibility, Quality Control & Pulp Production

The line production configuration possibilities described hereunder allow full flex-ibility regarding final requirement for bleaching profit and final ash content.

In case of off-specification pulp production due to either Waste Paper contamina-tion or transitory process upsets, the possibilities proposed allow proper handling of the off-spec pulp produced.

Bleaching steps series

According to waste paper characteristics and final desired quality, the following bleaching steps can be adjusted:- Loop 1 oxidative bleaching in Pollcon tower 07CPA01.- Loop 2 Reductive bleaching through Heating Screw 14VIT01 and reactive

Tube 14BLT07a & 14BLT07b.- If required, this Reductive bleaching is achieved in KRIMA dispersion system

(through Disperser 11KR06).

GENERALPage 13/264


Deashing system

Ash content in deinked pulp is proportional to production ratio sent to washing system (and then to filtrate flow to be treated by Micro-flotation).Feed production to Loop 3 washing is adjustable through Flowmeter FIC12005, commanding stock extraction from Transfer chest 12CPA06 (and then from Loop 2 Storage Tower 12CPA03). (Production can be calculated with consistency measured with NIC11075).Washing by-pass production is adjustable through Flowmeter FIC15095 (and cal-culated with stock consistency measured NRC11050).

The sum of Washing feed and By-pass productions gives the stock quantity to be processed by the 2 upstream deinking loops.

Case Loop 1 Accept pulp recycling to Start Chest

In the case the Pulp quality obtained at the Loop 1 Disc Filter Outlet is unaccept-able, or during transitory start-up conditions, the Pulp accepted from Loop 1 Disc Filter may be pumped back from MC Pump 05PMC10 to Start Chest 07CPA11 (and then pumped back to Dump Chest 01CPA15) with On/Off valve AV6010 forced closed and On/Off valve AV6006 open.

In this case, the Pulp Flow to Loop 2 is closed.

Case Loop 1 Dispersion system By-pass

In the case of malfunction of equipment in Dispersion system, or during special operating conditions, the Pulp accepted from Loop 1 Disc Filter may be sent dir-ectly to oxidative bleaching tower 07CPA01 with On/Off valve AV6015 forced closed (with On/Off valve AV6150 open) at Screw Press 06PVS01 inlet.

The upstream Loop 1 process throughput remains controlled as described above.

Case Loop 2 Accept pulp recycling to Start Chest

In the case the Pulp quality obtained at the Loop 2 Disc Filter Outlet is unaccept-able, or during transitory start-up conditions, the Pulp accepted from Loop 2 Disc Filter may be pumped back from MC Pump 14PMC03 to Start Chest 07CPA11 (and then pumped back to Dump Chest 01CPA15) with On/Off valve AV15035 forced closed and On/Off valve AV9015 open.

In this case, Reductive Bleaching is inactive: Heating Screw .14VIT01 is only used for stock conveying and steam

feed must be closed. Reductive chemicals injection must be closed.

Then the Pulp Flow to KRIMA dispersion is closed, the upstream Loop 1 & Loop 2 process throughputs remain controlled as described above.

GENERALPage 14/264


Case Loop 2 Hot Dispersion system By-pass

Same as in Loop 1, in the case of malfunction of an equipment in KRIMA Hot Dis-persion system, or during special operating conditions, the Pulp accepted from Loop 2 Disc Filter may be sent directly to Loop 2 reductive MC pump feed tank 12PMC02.

The downstream Loop 1 & Loop 2 process throughputs remain controlled as de-scribed above.

1.3.4 Ash control and Yield control in Pulp Production

The Ash & Fines content in the Pulp produced and related DIP Line Yield are controlled by the following process parameters:

- % of total production sent to Loop 3 washing. Then, as a consequence, % of Washers filtrates processed on Micro-flotation.

- % of Pre Flotation foam re-introduction to Prime Mac feed.

- % of Post Flotation foam re-introduction to Prime Mac feed.

- % of Micro-Flotation sludge re-introduction to Prime Mac feed.

GENERALPage 15/264


1.4 DIP LINE WATER BALANCE & CONTROLS

The DIP Line water is structured in 3 circulation Loops.

- Loop 1: from Waste Paper Pulping to Loop 1 Bleaching Tower;- Loop 2: from extraction of Loop 1 Bleaching Tower to Loop 2 Tower.- Loop 3: from extraction of Loop 2 Bleaching Tower to DNT Washers and

Storage Tower.

For each loop, the filtrates produced by the thickening equipment are used for di-lution of the thick stock entering the loop.

For loops 1-2-3, the operation of the line requires a filtrate make-up to balance water exportation through rejects and stock flows.

The Paper Machine process generates an excess of filtrates, which is used to cover the required make-up to DIP Line.

The object of Filtrate and Water controls is to:- Obtain a stable operation on the DIP Line filtrate & water flows, - Allow smooth start-up & shut-down, - Control water balance through all process variations without Low level or

overflows.

Water process control for each loop are detailed in each corresponding para-graph.

1.4.1 Loop 1 Filtrate balance controls

The Loop 1 dilution water tanks are the following:- Clear Filtrate Tank 05CE03, with level controller LIS5055, used for Cleaners

and Loop1 dilution pumps and overflowing into:

- Cloudy Filtrate Tank 05CE02, with level controller LIS5045, used for Flota-tion dilution and overflowing into

- Pulper Water tank 05CE04, with level controller LIC5010, used as transfer to

- Buffer Water tank 05CE11, with level controller LIS5000, used for Pulpers dilution (occurring high discontinuous flows). This tank has a big volume ca-pacity in order to store water during transitory phases (for example shutdown of Loop 1 when filtrate generated by thickening is no more consumed for Loop 1 process dilutions).

The make-up to Loop 1 is obtained from pump 10PPC09 (Loop 2 Periodic Fil-trates pump), through level controller LIC5010 (level decreasing in tank 05C04) commanding control valve LCV-5010.

The make-up from Loop 2 to Loop 1 Clear filtrate tank 05CE03 covers the water losses through the cleaning, screening and flotation processes.Design flow is to allow minimum for start-up & variations.

GENERALPage 16/264


Note: The Clear Filtrate Tank 05CE03 level controller LIS5055 and Cloudy Fil-trate Tank 05CE02 level controller LIS5045 will be adjusted as to respond rapidly to any variation in level.The Pulper Water tank 05CE04 level controller LIC5010 will be adjusted to act slowly to keep the Pulper Water Tank level trend stable.

The Water tank 05CE11 serves as buffer tank, and its level oscillates following the batch operation of the Pulper.

Normal variations in operation

When Dump Chest level goes down, either voluntarily or because of process vari-ation, the volume of water pumped out of Dump Chest flows to Loop 1 Filtrate tanks. This constitutes an excess of filtrate that ends up in Loop 1 Buffer Water Tank 05CE11.

To avoid overflow, it is required to have in operation enough storage available in Water Tank: i.e. the lowest water volume in Pulper Water Tank 05CE11.

On the other hand, when Dump Chest level goes up, i.e. on starting the DIP Line, the volume filling the Dump Chest will be supplied from Buffer Water Tank 05CE11. For a smooth start-up, it is required to have a sufficient level in Buffer Water Tank.

Repetition of strong variations in Dump Chest level should be avoided, as this will have the effect of filling up the Buffer Water chest with Loop 2 water with addi-tional call of PM White Water into the DIP Line.


The Loop 2 dilution tanks are the following:- Loop 2 Clear Filtrate Tank 10CE06, with level controller LIS9055, overflow-

ing into:

- Loop 2 Cloudy Filtrate Tank 10CE05, with level controller LIC9050.

The water make-up to Loop 2 is obtained from pump 13PPC09 (Loop 3 dilution pump), through control valve LCV-9050 to Clear water tank 10CE06, controlled by level controller LIC9050.Then make-up water feeds Clear filtrate tank 10CE06 and overflows to tank 10CE05.

The make-up from Loop 3 to Loop 2 covers the Loop 1 & Loop 2 water losses through the cleaning, screening and flotation processes.Design flow is to allow minimum for start-up & variations.

In case of Microflotator not used for deashing process (DNT washers stopped), then Loop 2 Clear Filtrate can be pumped through 10PPC10 to DAF feed tank 13CE07. After being processed by Poseidon, clarified filtrate flow back to Loop 2 through transfer pump 13PPC11.

GENERALPage 17/264



When Loop 1 Bleaching Tower level goes down, either voluntarily or because of process variation, the volume of water pumped out will be negligible compared to global water flows.

Operational priority will be to maintain level in Loop 2 filtrates tanks to smooth out all process variations.


The Loop 3 water tanks are the following:- Poseidon Feed tank 13CE07 with level controller LIC13010, recovering by

gravity the Filtrates accepted from Filtrates from DNT Washers or filtrates transferred from Loop 2 (in case DNT washers are not used).

- Loop 3 dilution tank 13CE08 with level controller LIC13005, recovering ac-cepted from Poseidon and PM water make-up. This tank is used for Loop 3 dilutions and make-up water.

Pump 13PPC10 feeds the Poseidon Clarifier at a controlled & fixed flow (in direct relation with level controller LIC13010 in order to operate Poseidon accordingly to DNT filtrates flow).

The make-up to Loop 3 is obtained from PM Clarified Water, through level con-troller LIC13005 acting on valve LCV-13005 commanding complement flow to Loop 3 tank 13CE08.

If required, pump 13PPC19 allows transferring filtrate from tank 13CE07 to an-other micro-flotation system in a parallel line (called existing VOITH line).In order to maintain a stable water balance in the whole system, the same water quantity must be repatriated from VOITH line in water tank 13CE08.

The make-up from PM Clarified Water to Loop tank 13CE08 covers the Loop 1, Loop 2 & Loop 3 water losses through the cleaning, screening and flotation pro-cesses.Design flow is to allow minimum for start-up & variations.


When Loop 2 Bleaching Tower level goes down, either voluntarily or because of process variation, the volume of water pumped out of will be negligible compared to global water flows.

Operational priority will be to maintain level in Loop 3 filtrates tanks to smooth out all process variations.

When Storage Tower 14CPA04 level goes down, either voluntarily or because of process variation, the volume of water pumped out of Storage Tower flows to Loop 3 Washer Filtrate tank 13CE07. This constitutes an excess of Loop 3 fil-trate.

GENERALPage 18/264


PROCESS DESCRIPTION


PRINTING - WRITING

PULPING AREA

PULPINGPage 19/264


3 PULPING

1.5 DESCRIPTION

Waste Paper Repulping system repulps the Waste Paper with DIP Line filtrates, with possible chemicals addition; the coarse contaminants are removed in the Dumping Poire.

The area process structure is as follows:

Pulping area is divided in two parallels identical systems complete from Waste pa-pers conveyor to dumping pump and able to run independently except for:- Dilution water is pumped from a common water tank 05CE11.- Pulped stock is sent to a common dump chest 01CPA15.

1.5.1 Pulping itemization

1.5.1.1 Pulping area 1

Waste paper conveyor .............................................................................01TAP01

Helico Pulper ...............................................................................01PH02

Hood for Helico Pulper ................................................................................01HT03

Pulper vapour exhaust fan.......................................................................................01ASP04

Hot water tank wit steam injectors............................................................................01CE05

Dumping Poire ................................................................................01PV06

Dump pump .............................................................................01PPC07

Water dilution pump .............................................................................05PPC12

Dosing tank Peroxide H202......................................................................................40CC29

Dosing tank Silicate Na2SIO3..................................................................................40CC30

Dosing tank Caustic Soda NaOH.............................................................................40CC31

Dosing tank DTPA ...............................................................................40CC32

Dosing tank Soap ...............................................................................40CC37


Waste paper conveyor .............................................................................01TAP08

Helico Pulper ...............................................................................01PH09

Hood for Helico Pulper ................................................................................01HT10

PULPINGPage 20/264


Pulper vapour exhaust fan.......................................................................................01ASP11

Hot water tank wit steam injectors............................................................................01CE12

Dumping Poire ................................................................................01PV13

Dump pump .............................................................................01PPC14

Water dilution pump .............................................................................05PPC13

Dosing tank Peroxide H202......................................................................................40CC33

Dosing tank Silicate Na2SIO3..................................................................................40CC34

Dosing tank Caustic Soda NaOH.............................................................................40CC35

Dosing tank DTPA ...............................................................................40CC36

Dosing tank Soap ...............................................................................40CC38

1.5.1.3 Equipment common to both pulping areas

Dump chest .............................................................................01CPA15

Dump chest agitator ...............................................................................01AG16

Transfer pump to continuous chest..........................................................................01PPC17

Pulper water tank ...............................................................................05CE11

1.5.2 Helico Pulper basics

1.5.2.1 Helico Pulper Description

The KADANT Helico Pulper consists of:- A stainless steel Pulper Vat, with support legs according to size.A Pulper Hood generally covers the Pulper Vat with extraction pipe to contain mist and steam generated by the filtrates used in the Pulper.- An accept chamber with accept stock outlet- A cast stainless steel High consistency Helico turbine machined and treated

according to the application. The rotor is driven in rotation by the vertical shaft of the mechanism.

- A complete rotating mechanism driving the screen rotor, with a vertical shaft and a water lubricated packed gland seal, running in two grease-lubricated bearings and depending on the Pulper size a mechanical gear drive or pulleys and V-belt drive.

The Pulper turbine remains in operation continuously during the Pulper operating cycle.

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ATTENTION: THE PULPER SHOULD NOT BE FED WITH FIBER WITHOUT A PRIOR PARTIAL FILLING OF FILTRATES. NON-OBSERVANCE WILL LEAD TO BLOCK THE PULPER DRIVE OR TO A RISK OF OVER-HEATING OF THE RAW MATERIAL & RELATED FIRE HAZARD.

ATTENTION: THE MAXIMUM WEIGHT LOAD OF RAW MATERIAL TO THE PULPER SHOULD NOT BE EXCEEDED NON OBSERVANCE MAY LEAD TO OVERLOAD THE PULPER DRIVE, LEAD TO DISRUPTION OF OPERATIONS.

ATTENTION: RUNNING THE PULPER WITH A WATER LOAD (WITHOUT FIBER) IN EXCESS OF THE DESIGN 25% FIRST FILLING VOLUME MAY LEAD TO SPILLAGE OF WATER or FILTRATES. IN CASE OF HOT OR CAUSTIC FIL-TRATES, INJURY MAY RESULT IF NON OBSERVANCE.

ATTENTION: MAINTENANCE PERSONNEL OR OPERATOR INTERVENTION ON THE PULPER MOVING PARTS OR IN/ABOVE THE PULPER VAT WILL BE DONE ACCORDING TO THE ADEQUATE SECURITY PROCEDURES, INCLUD-ING ISOLATION & LOCKING OF THE MCC FEEDER TO PULPER DRIVE, FIL-TRATES TO PULPER FEED PUMP, ISOLATION OR LOCKING OF FILTRATES FEED VALVES. INJURY MAY RESULT IF NON OBSERVANCE.

ATTENTION: WHERE APPLICABLE, SECURITIES & ALARMS ON DRIVE HY-DRAULICS MUST BE IMPLEMENTED ACCORDING TO KADANT or HYDRAUL-ICS SUPPLIER RECOMMENDATIONS AND OBSERVED RIGOROUSLY. FAIL-URE TO DO SO MAY LEAD TO DESTRUCTION OF THE DRIVE. STOPPING & RESTARTING REPEATEDLY THE PULPER DRIVE IS SUBJECT TO THE LIMIT-ATIONS ON PULPER DRIVE MOTOR.

1.5.2.2 Helico Pulper Sequence

See Associated Grafcet (will be supplied by Kadant).

1.5.3 Dumping Poire basics

1.5.3.1 Poire description

The KADANT Dumping Poire consists of:- A stainless steel Dump screen body comprising a large reject chamber, fitted

with a bolted front-end door-lid.- A screen plate with perforations as per application.- A Rotor -rotating in front of the perforated plate - with hydrofoils effect arranged

specifically for the application considered. The rotor is driven in rotation by the horizontal shaft of the mechanism.

- A complete rotating mechanism driving the rotor, with a horizontal shaft running in two grease-lubricated bearings and a water lubricated packed gland seal, pulleys and V-belt drive.

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- A supporting base for the Dump screen body and mechanism.

The Dumping Poire starts and stops at each Pulper discharge cycle.

1.5.3.2 Dumping Poire Sequence


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1.5.4 Pulping area


Waste paper loading to Pulper

Waste paper bales are dewired manually & dumped as Loose Paper on Pulper Conveyor 01TAP01.

The batches put on the conveyor are previously weighted by WIRS1045 to check the weight of materials going into the Pulper.

In general, the Waste Paper Handling system is controlled locally (local control panel with PLC, interfaced with DCS) for bales reception and de-wiring, waste pa-per controls for the system downstream. (To be checked and corrected with exact situation).

Afterwards, waste papers are dumped in the Pulper 01PH02 running & filled (25% level) with hot water and necessary chemicals.

Pulper 01PH02

The hot water tank 01CE05 receives the quantity of filtrate necessary for the next batch pulping from the distribution water (via pump 05PPC12).Level controller LIS1075 measures this tank level. High threshold LSH1075 closes filling On/Off valve AV-1070.Then filtrate is heated by mean of direct steam: Steam injection quantity (via con-trol valve TCV-1065) is adjusted through controller TIC1065 and must be adapted according to required temperature inside Water tank 01CE05.

From this water tank 01CE05, a line brings filling water into Pulper vat via auto-matic valve AV-1080. A hand valve MV-1066 is located upstream for adjustment of the filling water flow.

The volume of Filtrates is completed to the amount required for operation of the Pulper at a design of 14-16% operating consistency, and the Pulper operates for the Pulping time required for a proper dispersion of the fibers.

After the set Pulping time, if Dump chest 01CPA15 has enough room, the Dumping Poire 01PV06 cycle is set to ON.

Pulper 01PH02 rotor is driven in rotation with a gearbox equipped with security alarms FSAL1050 (cooling water flow Low alarm) and TSAH1055 (Gearbox tem-perature alarm).

The Pulper turbine remains in operation continuously during the Pulper operating cycle. The Dump screen starts and stops at each Pulper discharge cycle.

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Dumping Poire 01PV06

When the Dump Poire 01PV06 is running, the Pulper discharge proceeds.A manifold brings the water used to dilute the stock during this dumping sequence: the largest portion (about 60 to 70 %) is introduced directly at the Dump Poire inlet (via valve AV-1100), a further quantity goes into the Pulper tub (valve AV-1085), lastly a small quantity is sent through the tub bottom under the rotor to avoid stock building up there (valve AV-1095).The water quantities are measured by Flowmeter FIQS1106 to control the proper operation and regularity of the different phases of these dumping sequences.

Diluted pulp is pumped out of the Pulper vat towards the dump tank 01CPA15 through the Dump Poire 01PV06 by the Pulper dump pump 01PPC07 at a 4,5-5,0% consistency.

At the discharge of pump 01PPC07, a regulating command valve HIC1115 is in-stalled to allow 3 different flows:- -A closed position to avoid pulp return.- -An open position for complete closing of the flow to the tank.- -A selected half close position used during Dumping Poire screen washing

step.

The flow through the Dump Poire is an important factor to ensure the equipment’s proper operation and efficiency. Too fast, it will carry through more contaminants. Too slow, it will effect dumping time.After a set time, if the Dump screen has not been set to Thickening step (auto alarm or manual), the Pulper Discharge proceeds to Thickening and Emptying, and the cycle re-starts.

When the Pulper Discharge valve AV-1060 closes, Dumping Poire 01PV06 se-quence goes to Rejects Thickening, Draining, Rejects Dumping and Water Filling.The Poire motor stops if the Pulper is not in Discharge step.

During the dumping of rejects (Flap valve AV-1105 opens), the regulating valve HCV-1115 has to be shut to prevent from discharge of the pulp contained in the feed pipe of tank 01CPA15.

A motor amp-load high intensity alarm JISH1110 helps to detect an eventual mal-function during Dumping Poire 01PV06 operation.


Waste paper loading to Pulper

Waste paper bales are dewired manually & dumped as Loose Paper on Pulper Conveyor 01TAP08.

The batches put on the conveyor are previously weighted by WIRS1345 to check the weight of materials going into the Pulper.

In general, the Waste Paper Handling system is controlled locally (local control panel with PLC, interfaced with DCS) for bales reception and de-wiring, waste pa-

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per controls for the system downstream. (To be checked and corrected with exact situation).

Afterwards, waste papers are dumped in the Pulper 01PH09 running & filled (25% level) with hot water and necessary chemicals.

Pulper 01PH09

The hot water tank 01CE12 receives the quantity of filtrate necessary for the next batch pulping from the distribution water (via pump 05PPC13).Level controller LIS1375 measures this tank level. High threshold LSH1375 closes filling On/Off valve AV-1370.Then filtrate is heated by mean of direct steam: Steam injection quantity (via con-trol valve TCV-1365) is adjusted through controller TIC1365 and must be adapted according to required temperature inside Water tank 01CE12.

From this water tank 01CE12, a line brings filling water into Pulper vat via auto-matic valve AV-1380. A hand valve MV-1379 is located upstream for adjustment of the filling water flow.

The volume of Filtrates is completed to the amount required for operation of the Pulper at a design of 14-16% operating consistency, and the Pulper operates for the Pulping time required for a proper dispersion of the fibers.

After the set Pulping time, if Dump chest 01CPA15 has enough room, the Dumping Poire 01PV13 cycle is set to ON.

Pulper 01PH09 rotor is driven in rotation with a gearbox equipped with security alarms FSAL1350 (cooling water flow Low alarm) and TSAH1355 (Gearbox tem-perature alarm).

Dumping Poire 01PV13

When the Dump Poire 01PV13 is running, the Pulper discharge proceeds.A manifold brings the water used to dilute the stock during this dumping sequence: the largest portion (about 60 to 70 %) is introduced directly at the Dump Poire inlet (via valve AV-1400), a further quantity goes into the Pulper tub (valve AV-1390), lastly a small quantity is sent through the tub bottom under the rotor to avoid stock building up there (valve AV-1395).The water quantities are measured by Flowmeter FIQS1405 to control the proper operation and regularity of the different phases of these dumping sequences.

Diluted pulp is pumped out of the Pulper vat towards the dump tank 01CPA15 through the Dump Poire 01PV13 by the Pulper dump pump 01PPC14 at a 4,5-5,0% consistency.

At the discharge of pump 01PPC14, a regulating command valve HIC1420 is in-stalled to allow 3 different flows:- -A closed position to avoid pulp return.- -An open position for complete closing of the flow to the tank.- -A selected half close position used during Dumping Poire screen washing

step.

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The flow through the Dump Poire is an important factor to ensure the equipment’s proper operation and efficiency. Too fast, it will carry through more contaminants. Too slow, it will effect dumping time.After a set time, if the Dump screen has not been set to Thickening step (auto alarm or manual), the Pulper Discharge proceeds to Thickening and Emptying, and the cycle re-starts.

When the Pulper Discharge valve AV-1360 closes, Dumping Poire 01PV13 se-quence goes to Rejects Thickening, Draining, Rejects Dumping and Water Filling.The Poire motor stops if the Pulper is not in Discharge step.

During the dumping of rejects (Flap valve AV-1410 opens), the regulating valve HCV-1420 has to be shut to prevent from discharge of the pulp contained in the feed pipe of tank 01CPA15.

A motor amp-load high intensity alarm JISH1415 helps to detect an eventual mal-function during Dumping Poire 01PV13 operation.

1.5.4.3 Buffer water tank 05CE11

This tank is filled with filtrate by pump 05PPC05 connected on water tank 05CE04.

From this tank, pump 05PPC12 ensure Pulper 01PH02 dilution and pump 05PPC13 ensures Pulper 01PH09 dilution.

Water tank 05CE11, additionally to being a buffer for the discontinuous Pulper Wa-ter consumption, is used to absorb variation in water needs on the DIP Line related to Pulp Storage levels. (See § 1.4.1 - Loop 1 Filtrate balance controls).

Controller LIS5000 measures tank 05CE11 level continuously.Low level in tank 05CE11 must be adjusted in order to always assume a minimum reserve volume of water corresponding to a water total quantity required for a dumping cycle.Level set-point must correspond to normal operating level on the Pulper Water Tank. This level will oscillate at the rhythm of the Pulper batch cycles, and the con-troller long integration will ensure that on a 15 minutes period, the Water taken out by the Pulper is smoothly made-up.

1.5.4.4 Dump chest 01CPA15

The Dumping Chest 01CPA15 has a volume sufficient to ensure storing between this first step of the process, which is sequential, and the following steps, which are continuous.Controller LIS1425 measures chest level continuously.

Pump 01PPC17 transfers pulp stock to downstream Holes screening.

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1.6 BASIC OPERATING CAPACITY

Pulpers: 2 x PH35On the basis of a Pulper PH 35 m3 feed 5200 BDkg/batch, (i.e. 14 to 16% pulping consistency), and sequence time at design 30 to 40 minutes, the basic operating capacity of the sub-system is 200-250 BDt/24h.

Then basic operating capacity of Pulper area (2 x PH35 in parallel) is 400-450 BDt/24h.

Dumping Poire: 2 x PV3/3 with perforated plate (holes 6 mm)

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1.7 TRANSMITTERS AND CONTROL LOOPS

1.7.1 Pulping area 1

Item Function DescriptionAlarms Scale-0-

100%Value unitLL L H HH

LIS 1000 Soap dosing tank 40CC37 levelL(1)

H(1)

0–300 lit

LIS 1005 Peroxide dosing tank 40CC29 levelL(1)

H(1)

0–150 lit

LIS 1015Silicate Na2SIO3 dosing tank 40CC30 level

L(1)

H(1)

0–700 lit

LIS 1025Caustic Soda NaOH dosing tank 40CC31 level

L(1)

H(1)

0–300 lit

LIS 1035 DTPA dosing tank 40CC32 levelL(1)

H(1)

0–100 lit

WIRS 1045Waste Paper weighing on Pulper con-veyor 01TAP01

L(1)

H(1)

6500 0-7000 kg

FSAL 1050Pulper 01PH02 gear cooling water flow alarm

L

TSAH 1055 Pulper 01PH02 gear temperature alarm H

FSA 20140Pulper 01PH02 sealing water Low flow alarm

L Digital alarm

TIC 1065Hot water tank 01CE05 heating temper-ature control

40 70 20-100°C

LIS 1075 Hot water tank 01CE05 level controlL(1)

H1(1)

H2(1)

HH(1)

0-35m3

LIS 1090 Pulper 01PH02 vat level controlLL(1)

L(1)

H(1)

HH(1)

0-35m3

FIQS 1106Pulper dumping water dilution flow counter

99%0-1000 m3/h

%

JISH 1110 Dumping Poire 01PV06 drive Amp Load 95% 100% 0-150%

FSA 20145Dumping Poire 01PV06 sealing water Low flow alarm

L Digital alarm

HIC 1115Dump pump 01PPC07 delivery flow con-trol

0-100%

(1) Values to be adjusted on start-up (according to process conditions & overall installation)

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LIS 1300 Soap dosing tank 40CC38 level L (1) H (1) 0–300 lit

LIS 1305 Peroxide dosing tank 40CC33 level L (1) H (1) 0–150 lit

LIS 1315 Na2SIO3 dosing tank 40CC34 level L (1) H (1) 0–700 lit

LIS 1325 NaOH dosing tank 40CC35 level L (1) H (1) 0–300 lit

LIS 1335 DTPA dosing tank 40CC36 level L (1) H (1) 0–100 lit

WIRS 1345Waste Paper weighing on Pulper con-veyor 01TAP08

L (1) H (1) 6500 0-7000 kg

FSAL 1350Pulper 01PH09 gear cooling water flow alarm

L

TSAH 1355 Pulper 01PH09 gear temperature alarm H

FSA 20150Pulper 01PH09 sealing water Low flow alarm

L Digital alarm

TIC 1365Hot water tank 01CE12 heating temper-ature control

40 70 20-100°C

LIS 1375 Hot water tank 01CE12 level controlL(1)

H1(1)

H2(1)

HH(1)

0-35m3

LIS 1385 Pulper 01PH09 vat level controlLL(1)

L(1)

H(1)

HH(1)

0-35m3

FIQS 1405Pulper dumping water dilution flow counter

99% 0-1000 m3/h%

JISH 1415 Dumping Poire 01PV13 drive Amp Load 95% 100% 0-150%

FSA 20155Dumping Poire 01PV13 sealing water Low flow alarm

L Digital alarm

HIC 1420 Dump pump 01PPC14 flow control 0-100%


1.7.3 Common to both Pulper areas



LIS 1425 Dumping chest 01CPA15 level controlL(1)

H1(1)

H2(1)

HH(1)

0-600 m3

LIS 5000 Pulper water tank 05CE11 level controlL(1)

LL(1)

H(1)

HH(1)

0-500 m3

(1) Values to be adjusted on start-up (according to process conditions)

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1.8 INTERLOCKINGS AND ALARMS

Interlocks are designed to avoid situations leading to disruption of operations or damage to equipment. These securities are not absolute and KADANT recom-mendations for operation are to be respected.


1- PULPER 01PH02 & GEARBOX ALARMS

If The gearbox oil temperature is High (TSAH1055) or the oil flow is Low (FSAL1050)

Then If Pulper 01PH02 motor is stopped: it can't startIf Pulper 01PH02 motor is running: it stops

2- PULPER WATER TANK 01CE05 LEVEL LIS1075 & TEMPERATURE TIC1065 TO STEAM VALVE TCV-1065

If Temperature TIC1065 is High-HighOr Water tank 01CE05 level LIS1075 is Low

Then Steam valve TCV-1065 is forced closed (Hard interlock).

If Temperature TIC1065 is High (High = set-point+ 5°C)Then Steam Valve TCV-1065 in Auto is closed (Soft interlock).

If Temperature TIC1065 is Low (Low= set-point- 5°C)Then Steam Valve TCV-1065 in Auto is opened (Soft interlock).

3- PULPER WATER TANK 01CE05 LEVEL LIS1075, PULPER WATER PUMP 05PPC12 TO MAKE-UP VALVE AV-1070

If Water tank 01CE05 level LIS1075 is High-HighOr Pulper Water Pump 05PPC12 is not running

Then Make-up valve AV-1070 is forced closed (Hard interlock).

If Water tank 01CE05 level LIS1075 is not High-HighAnd Pulper Water Pump 05PPC12 is running

Then Make-up valve AV-1070 is allowed to Open (according to Pulping sequence).

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4- PULPER 01PH02 FILLING VALVE AV-1080 & DUMP VALVE AV-1060

If Pulper 01PH02 Filling Valve AV-1080 is not closedThen Pulper 01PH02 Dump Valve AV-1060 is forced Closed

If Pulper 01PH02 Dump Valve AV-1060 is not closedThen Pulper 01PH02 Filling Valve AV-1080 is forced Closed

5- PULPER WATER PUMP 05PPC12 INTERLOCK TO DILUTION VALVES

If Pulper Water Pump 05PPC12 is not running (On delay T=10s)

Then Pulper Top dilution Valve AV-1085 is forced closedAnd Pulper Bottom dilution Valve AV-1095 is forced closedAnd Poire dilution Valve AV-1100 is forced closed

Reset interlock On-delay=10s after pump is running.

6- DUMPING POIRE 01PV06 to PULPER DUMP PUMP 01PPC07

If Dumping Poire 01PV06 is not running

Then Stop Pulper dump pump 01PPC07

7- DUMP CHEST 01CPA15 LEVEL LIS1425 to PULPER PUMP 01PPC07

If Dump chest 01CPA15 level LIS1425 is High


8- PULPER DUMP VALVE AV-1060 & DUMP POIRE REJECT VALVE AV-1105

If Pulper Dump Valve AV-1060 is not closedThen Dump Poire Reject Valve AV-1105 is forced Closed

If Dump Poire Reject Valve AV-1105 is not closedThen Pulper Dump Valve AV-1060 is forced Closed

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9- PULPER DUMP PUMP 01PPC07 TO SLAVE VALVE HCV-1115

If Pulper dump pump 01PPC07 is not runningThen Control valve HCV-1115 is forced closed (Hard interlock)

If HD Pulper pump 01PPC07 is runningThen With on delay T=5s, Control valve HCV-1115 is opened (Soft interlock)

10- (RESERVE)

11- (RESERVE)

ALARMS

12- PULPER 01PH02 SEALING WATER ALARM

If Pulper 01PH02 main drive is runningAnd Sealing water flow FSA20140 is on Alarm Low

Then Set Pulper 01PH02 sealing water alarm

13- DUMPING POIRE 01PV06 SEALING WATER ALARM

If Dumping Poire 01PV06 motor is runningAnd Sealing water flow FSA20145 is on Alarm Low

Then Set Poire 01PV06 sealing water alarm

14- (RESERVE)


15- PULPER 01PH09 & GEARBOX ALARMS

If The gearbox oil temperature is High (TSAH1355) or the oil flow is Low (FSAL1350)

Then If Pulper 01PH09 motor is stopped: it can't startIf Pulper 01PH09 motor is running: it stops

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16- PULPER WATER TANK 01CE12 LEVEL LIS1375 & TEMPERATURE TIC1365 TO STEAM VALVE TCV-1365

If Temperature TIC1365 is High-HighOr Water tank 01CE12 level LIS1375 is Low

Then Steam valve TCV-1365 is forced closed (Hard interlock).

If Temperature TIC1365 is High (High = set-point+ 5°C)Then Steam Valve TCV-1365 in Auto is closed (Soft interlock).

If Temperature TIC1365 is Low (Low= set-point- 5°C)Then Steam Valve TCV-1365 in Auto is opened (Soft interlock).

17- PULPER WATER TANK 01CE12 LEVEL LIS1375, PULPER WATER PUMP 05PPC13 TO MAKE-UP VALVE AV-1370

If Water tank 01CE12 level LIS1375 is High-HighOr Pulper Water Pump 05PPC13 is not running

Then Make-up valve AV-1370 is forced closed (Hard interlock).

If Water tank 01CE12 level LIS1375 is not High-HighAnd Pulper Water Pump 05PPC13 is running

Then Make-up valve AV-1370 is allowed to Open (according to Pulping sequence).

18- PULPER 01PH09 FILLING VALVE AV-1380 & DUMP VALVE AV-1360

If Pulper 01PH09 Filling Valve AV-1380 is not closedThen Pulper 01PH09 Dump Valve AV-1360 is forced Closed

If Pulper 01PH09 Dump Valve AV-1360 is not closedThen Pulper 01PH09 Filling Valve AV-1380 is forced Closed

19- PULPER WATER PUMP 05PPC13 INTERLOCK TO DILUTION VALVES

If Pulper Water Pump 05PPC13 is not running (On delay T=10s)

Then Pulper Top dilution Valve AV-1390 is forced closedAnd Pulper Bottom dilution Valve AV-1395 is forced closedAnd Poire dilution Valve AV-1400 is forced closed

Reset interlock On-delay=10s after pump is running.

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20- DUMPING POIRE 01PV13 to PULPER DUMP PUMP 01PPC14

If Dumping Poire 01PV13 is not running


21- DUMP CHEST 01CPA15 LEVEL LIS1425 to PULPER PUMP 01PPC14

If Dump chest 01CPA15 level LIS1425 is High


22- PULPER DUMP VALVE AV-1360 & DUMP POIRE REJECT VALVE AV-1410

If Pulper Dump Valve AV-1360 is not closedThen Dump Poire Reject Valve AV-1410 is forced Closed

If Dump Poire Reject Valve AV-1410 is not closedThen Pulper Dump Valve AV-1360 is forced Closed

23- PULPER DUMP PUMP 01PPC14 TO SLAVE VALVE HCV-1420

If Pulper dump pump 01PPC14 is not runningThen Control valve HCV-1420 is forced closed (Hard interlock)

If HD Pulper pump 01PPC14 is runningThen With on delay T=5s, Control valve HCV-1420 is opened (Soft interlock)

24- (RESERVE)

25- (RESERVE)

ALARMS

26- PULPER 01PH09 SEALING WATER ALARM

If Pulper 01PH09 main drive is runningAnd Sealing water flow FSA20150 is on Alarm Low

Then Set Pulper 01PH09 sealing water alarm

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27- DUMPING POIRE 01PV13 SEALING WATER ALARM

If Dumping Poire 01PV13 motor is runningAnd Sealing water flow FSA20155 is on Alarm Low

Then Set Poire 01PV06 sealing water alarm

28- (RESERVE)

1.8.3 Common to both Pulper areas

29- DUMP CHEST 01CPA15 LEVEL LIS1425 to EXTRACTION PUMP 01PPC17

If Dump chest level LIS1425 is LowThen Stop Transfer Pump 01PPC17

If Tank level LIS1425 is LowThen Inhibit start of Transfer Pump 01PPC17

30- DUMP CHEST LEVEL LIS1425 TO AGITATOR 01AG16

If Dump chest level LIS1425 is Low-LowThen Stop Agitator 01AG16

If Dump chest level LIS1425 is LowThen Inhibit Start Agitator 01AG16

If Dump chest level LIS1425 is not LowAnd Agitator 01AG16 in DCS Auto mode

Then Start Agitator 01AG16

31- TRANSFER PUMP 01PPC17 AUTO-START & INTERLOCK FROM SCREENING FEED CHEST 02CPA01 LEVEL LICS2005

If Feed Chest Level LICS2005 is High-HighThen Stop Transfer Pump 01PPC17

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ALARMS

32- SEALING WATER

If Pulper area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s

Then Active the ALARM

33- COMPRESSED AIR

If Pulper area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


34- BUFFER TANK 05CE11 LEVEL LIS5000

If Buffer tank 05CE11 level LIS5000 is High-High


35- (RESERVE)

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1.9 OPERATION

Notes: Both Pulper areas work in parallel and then refer to the identical Start-up and shutdown sequences. Only one sequence of each is described hereunder but is applicable to both areas.

The following sequences are an explanation going with function charts describing all Pulping area operation. Programming must be done in priority with Func-tion charts (supplied separately by Kadant).

1.9.1 Start-up

Basic conditions:- Sealing water main line is under pressure and Flow switch

FSA20135 is not alarm Low.- Compressed air system is under pressure (pressure PIA19202 not on Alarm

Low).- Pulper water tank 05CE04 level LIC5010 is not Low.

Fill buffer tank 05CE11 through feed pump 05PPC05 up to a sufficient level in or-der to start a Pulper cycle.

Open sealing water valves for Pulpers (SV-19314 for 01PH02 and SV-19318 for 01PH09) and Dumping Poire (SV-19316 for 01PV06 and SV-19320 for 01PV13).

Pulper filling tanks 01CE05 & 01CE12If tank 01CE05 (or 01CE12) is empty, start Pulper water pump 05PPC12 (or 05PPC13) in order to fill the tank up to High level.

Then Heating controller TIC1065 (or TIC1365) is enabled.

Waste paper conveyor loading Loading of the selected quantity of waste paper on the conveyor 01TAP01 (or 01TAP08) by controlling the indicated weight WIRS1045 (or WIRS1345).

Pulper filling (Refer to associated Grafcet)

Start of hood exhaust fan 01ASP04 (or 01ASP11).

Start of motors of cooling blower 01PH02c (or 01PH09c), re-circulation pump 01PH02b (or 01PH09b), and then of main Pulper drive 01PH02a (or 01PH09a).

Opening of valve AV-1080 (or AV-1380) for filling the Pulper with water.

As soon as a minimum volume (about 25 %) has been reached, starting of con-veyor for introduction of paper. The conveyor stops automatically after a pre-set time or after no presence of waste paper on the conveyor.

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Introduction of chemicals:- Peroxide H2O2- Silicate Na2SIO3- Soda NaOH- DTPA- Soap

As soon as the Pulper is filled with the whole water quantity: closing of filling valve AV-1080 (or AV-1380).

Pulping (Refer to associated Grafcet)As soon as the Pulper is correctly filled (water, chemicals and paper): countdown of pulping time.

At the end of pulping time: If there is enough volume available in the dump Chest 01CPA15: Pulper

is emptied through the Dump Poire 01PV06 (or 01PV13). If there is not enough volume available in dump Chest 01CPA15: waiting

time = 5 minutes. If after these 5 minutes, there is still not enough volume available, the Helico Pulper motor stops and only starts again when there is sufficient volume in the tank.

Pulper dumping (Refer to associated Grafcet)Water filling of Dumping Poire via the dilution valve at the unit inlet (AV-1100 for 01PV06 and AV-1400 for 01PV13).

Start of Dumping Poire motor.

Opening of Pulper dump valve (AV-1060 for 01PV06 and AV-1360 for 01PV13).

Start of Pulper pump 01PPC07 (or 01PPC14) and control valve HCV-1115 (or HCV-1420) opens to pre-set position.

Opening of dilution valves AV-1085 and AV-1095 for Pulper 01PH02 (AV-1390 and AV-1395 for Pulper 01PH09).

Pulper dumping time is controlled through timer.

At the end of dumping time, closing of dilution valves AV-1085 and AV-1095 for Pulper 01PH02 (AV-1390 and AV-1395 for Pulper 01PH09).

Discharge of the water remaining in the Pulper bottom (phase called “ Exhaus-tion ”).

Closing of Pulper dump valve (AV-1060 for 01PV06 and AV-1360 for 01PV13).

Once the valve is shut, the Pulper cycle can restart without waiting for the end of the Dumping Poire cycle.

PULPINGPage 39/264


Washing of contaminants (Refer to associated Grafcet)Water valve at the inlet of the Dumping Poire (AV-1100 for 01PV06 and AV-1400 for 01PV13) is still open, and then the water washes the contaminants to rid them of residual fibers.

Closing of the Dumping Poire’s water valve (AV-1100 for 01PV06 and AV-1400 for 01PV13).

Exhaustion by the pump 01PPC07 (or 01PPC14) of most of the water remaining in the Dumping Poire.

Stop of Pulper dump pump 01PPC07 (or 01PPC14) and closing the valve HCV-1115 (or HCV-1420).

Discharge of contaminants (Refer to associated Grafcet)Opening of Dump Poire reject valve (AV-1105 for 01PV06 and AV-1410 for 01PV13): the contaminants are carried away by the water volume remaining in the Dumping Poire.

Closing of the reject valve (AV-1105 for 01PV06 and AV-1410 for 01PV13) after a pre-set time.

Remark:In case of overload of the Dumping Poire motor (perhaps from a too large quantity of contaminants or from clogging), one goes directly over to the washing of the contaminants of the Dump Poire. In that case, at the end of the Dumping Poire cycle, another cycle will automatically be re-launched to complete Pulper dumping.

PULPINGPage 40/264


1.9.2 OperationThe different steps run off automatically.Monitoring only consists in checking the correct course of these cycles:- Monitoring of cycle times,- Monitoring of consistencies.- Check if no fiber in Compactor outlet.- Monitoring of inlet and outlet pressures of Cleaner if used.

1.9.3 Stop

Refer to associated Grafcet.

On requesting the stop of automatic operation, pulping, chemicals dosing systems and dumping are carried out normally, the Pulper and Dump screen only stopping at cycle end.

Remark:All steps are controlled by delay times or thresholds to be defined on DCS during the start-up or optimising phases according to raw materials with the exception of the Pulper dumping delay which is set on.

PULPINGPage 41/264


PROCESS DESCRIPTION


PRINTING - WRITING

HD CLEANING &HOLES SCREENING AREA

HD CLEANING – HOLES SCREENINGPage 42/264


4 HD CLEANING AND HOLE SCREENING

1.10 DESCRIPTION

1.10.1 HD Cleaning and Holes screening Itemization

Holes screening feed tank........................................................................................02CPA01

Holes screening feed tank agitator...........................................................................02AG02

Holes screening feed pump......................................................................................02PPC03

High-density cleaner 1 .............................................................................02EPE04



HD Cleaners dilution pump......................................................................................02PPC07

Stage 1 Horizontal screen 1.....................................................................................02CH08

Stage 1 Horizontal screen 2.....................................................................................02CH09

Holes screening reject tank......................................................................................02CPA10

Holes screening reject tank agitator.........................................................................02AG11

Stage 2 screening feed pump..................................................................................02PPC12

Stage 2 Horizontal screen........................................................................................02CH13

Auxiliary holes screen Diabolo.................................................................................02DIA14

Constant level box ...............................................................................02CP15



1.10.2 High Density Cleaner basics

1.10.2.1 HD Cleaner Description

The High-Density Cyclone is a centrifugal cleaner, or hydro-cyclone, designed for the elimination of heavy contaminants (specific gravity superior to 1) from a stock flow of up to 4,5% consistency. It protects the downstream equipment from abra-sion-related wear and deterioration by those contaminants.

The Heavy contaminants considered here are staples, paper clips and metal frag-ments, sands, glass, …

1.10.2.2 HD Cleaner Operation

The Cleaner head with tangential stock inlet impels a rotating downward move-ment to the stock flow. The heavy contaminants are centrifuged against the wall of the cleaner cone and flow downward to the cleaner reject trap, where they are collected. The clean stock flows back upwards at the centre of the cyclone to the accept nozzle of the cleaner.


Accept flow

Inlet flow

Reject Periodic

Air/Degassing

Counter-pressure(filtrates -fixed P)

Filling

Trap

Cone

Head

Body

Figure: HD Cleaner Principle


The counter-pressure pressure water flow (continuous clear filtrates, or water) re-covers the fiber captured with the heavy contaminants and contributes to the con-trol of the cyclone vortex at the bottom of the cleaner. Proper setting of the counter-pressure pressure water flow is required for optimal operation.

The Reject trap at the bottom of the Cleaner collects the Heavy rejects. Periodic-ally, the Reject trap is isolated from the cleaner by a sliding gate-valve for flush-ing of the accumulated rejects according to a set-time sequence

During the flushing cycle, the feeding of the HD Cleaners remains uninterrupted; with rejects accumulating for a short time in the lower part of the cleaner cone.

High Density Cleaner requires a backpressure of 10 mWC on the accepted flow.

A H.D. Cleaner is characterized by its pressure loss curve against flow in given conditions: for adequate operation, the pressure differential across the cleaners is 12-18 mWC.

1.10.2.3 HD Cleaner Sequence


1.10.3 Horizontal screen (CH) basics

1.10.3.1 Horizontal screen (CH) Description

The CH Horizontal screen operates continuously up to 4,0%.The perforation size and operating consistency depends on the process applica-tion.

The KADANT CH Screen consists of:- A stainless steel horizontal cylindrical body, fitted with a bolted front end door-

lid and a back-end spiral-shaped reject chamber;- A screen basket with fine perforations, with micro-vortex surface;- A Rotor -rotating on interior of basket- fitted with hydrofoils arranged specific-

ally for the application considered. The rotor is driven in rotation by the hori-zontal shaft of the mechanism;

- A complete rotating mechanism driving the screen rotor, with a horizontal shaft running in two grease-lubricated bearings and a water lubricated packed gland seal, pulleys and V-belt drive;

- A supporting base for the screen body and mechanism.



1.10.3.2 Horizontal screen (CH) Operation

The 3,0-3,5% stock is introduced in the CH Screen at the top and front of the screen body, tangentially to the wall of the screen body. The pulp flows towards the screen basket and rotor.

The screen perforation allows the passage of the fiber in the stock to the AC-CEPTS compartment of the screen. Contaminants do not pass the perforations, and continue their flow downward towards the REJECTS spiral chamber & outlet.

The rotating rotor foils generate a rotating local pressure pulsation on the screen: first a light pressure pushing the pulp through the basket, second a strong de-pression generating a local counter flow, which frees the basket surface from po-tential plugging.

The CH screen requires a backpressure of 10 mWC on the accepted flow.

The reject flow is the main operating control parameter.

The pressure differential across the screen basket (Accept/Inlet) is 3-5 mWC in normal operating conditions. The value is checked for verification of the proper operation of the screen.

1.10.3.3 Horizontal screen (CH) Sequence



Horizontal CH Screen Overview:

Stock inlet

Basket

Rotor

Body

Stock Accept

Rejects

Rejects dilutionto CH"T" Pipe

Rejects dilution- Rejects Chamber


1.10.4 Tailing screen Diabolo

1.10.4.1 Diabolo Description

The DIABOLO screen operates with accumulation of the rejects and periodic discharge, with Holes or Slots perforation depending on the application. The op-erating consistency (1,5-2,0%) depends of the process application.

The KADANT DIABOLO Tailing Screen consists of:- A stainless steel Diabolo body comprising a large reject chamber, fitted with a

bolted front end door-lid;- A Rotor -rotating on interior of basket for basket Diabolo; rotating in front of

the perforated plate for standard Diabolo- fitted with hydrofoils arranged spe-cifically for the application considered. The rotor is driven in rotation by the horizontal shaft of the mechanism;

- A complete rotating mechanism driving the screen rotor, with a horizontal shaft running in two grease-lubricated bearings and a water lubricated packed gland seal, pulleys and V-belt drive;

- A supporting base for the screen body and mechanism.

1.10.4.2 Diabolo Operation


KADANT Diabolo Tailing Screen

Inlet Accept

Rejectsperiodic

AcceptDraining

Basket

Rotor

Reject Chamber

De-aeration

Accept Chamber

Washing


The Diabolo is the Tailing screen, last stage of the Pre-Screening system ensur-ing a very Low fiber loss in the rejects through its washing cycle prior to dis-charge of the rejects.

The 2-2,5% screening rejects are introduced in the Diabolo Screen at the top and front of the screen body, tangentially to the wall of the screen body. The pulp flows towards the screen basket and rotor.

The screen perforation allows the passage of the fiber in the diluted stock to the ACCEPTS compartment of the screen. Contaminants do not pass the perfora-tions, and are accumulated in the REJECTS chamber.

The rotating rotor foils generate a rotating local pressure pulsation on the screen plate or basket: first a light pressure pushing the pulp through the basket, second a strong depression generating a local counter flow, which frees the perforated plate or basket surface from potential plugging.

Periodically or in case of accept low pressure alarm, or in case of drive overload alarm, the accumulated rejects are washed and dumped according to a set-time flushing sequence (See Grafcet)

After the Dumping cycle, the Diabolo fills up on filtrates through the Wash valve (20-40 seconds) and resumes screening operation. The Diabolo drive operates continuously during the sequence.

The Diabolo screen requires a backpressure of 5-10 mWC on the accepted flow.

The Diabolo screen is operated without any other regulation than the start-up set-ting of the manual valves on the equipment, and trigger of the rejects dumping step according to Screen differential pressure or drive overload alarm.

The pressure differential across the Diabolo screen basket (Accept/Inlet) is 3-4 mWC in normal working conditions. The value is monitored to trigger the Rejects dumping step on alarm high.

The Diabolo drive load is monitored to trigger the Rejects dumping step on alarm high.

1.10.4.3 Diabolo Sequence




1.10.5 HD Cleaning and Holes Screening Area

The area process structure is as follows:

From the dumping tank 01CPA15, pump 01PPC17 feeds the stock chest 02CPA01 that is a constant level working chest.The level control LICS2005 commands the stock quantity required upstream the system.

1.10.5.1 High Density Cleaning

Pump 02PPC03 on Holes screening chest 02CPA01 feeds the 3 parallel HD Cleaners (02EPE04, 02EPE05 and 02EPE06) with the pulped stock at a con-trolled consistency (through regulation loop NRC2010) of 3,0-4,0%.

HD Cleaners heavy rejects flow by gravity periodically through an automatic se-quence.

The following pressures are obtained from pressure transmitters:

Item Inlet Pressure Accept Pressure Differential Pressure

02EPE04 PIS2030 PIS2045 PdIS2050



HD Cleaners accepted stock feed directly the 2 parallel Horizontal screens 02CH08 and 02CH09 at a pressure adjusted by control loop PIC2125 with control valve PCV-2125 on pulp pipe recycling to feed chest 02CPA01.This configuration of circuit enables HD Cleaners operation at constant rating, whatever the production. Malfunctions or possible problems are thus more easily detected.

Counter-pressure & trap filling water to the HD Cleaners is obtained from Booster Pump 02PPC07. Dilution pressure is continuously checked by PIS2020.

1.10.5.2 Pre-screening Holes 3 Stages

The Pre-screening system processes the 3,0-4,0% pulp on a 3-stage screen holes system.

Stage 1 Screens 02CH08 & 02CH09:

The Stage 1 is composed of 2 Horizontal screens (02CH08 and 02CH09) working in parallel.

Screen 02CH08 inlet and accept pressures are respectively measured by trans-mitters PIS2305 and PIS2320. Then differential pressure PdIS2325 is calculated and helps to check proper operation of Horizontal screen.



Idem for Horizontal Screen 02CH09: inlet pressure is measured by transmitter PIS2355, accept pressure by PIS2365 and differential pressure PdIS2370 is then deduced.

Stage 1 screening accepted pulp flow to Constant Level Box 02CP15.Accept flow from each screen is adjustable through a hand-command control valve (HIC2330 for 02CH08 and HIC2380 for 02CH09) and measured by FI2335 for 02CH08 and FI2375 for 02CH09.

Constant level box 02CP15 feeds Slots pre-screening area. An overflow connec-ted to Screening feed chest 02CPA01 enables the whole area operation at con-stant rating, whatever the production variations.

After being diluted in line (through On/Off valves AV-2340 for 02CH08 and AV-2385 for 02CH09), Stage 1 screens rejects are routed to Reject chest 02CPA10.Reject flow from each screen are regulated with flow controllers (FFIC2345 for 02CH08 and FFIC2390 for 02CH09) whose set-points are calculated in direct ra-tio with accept flows and accordingly to a pre-set reject rate in %.

Reject chest 02CPA10:

Rejects chest 02CPA10 collects: Primary Screens 02CH08 & 02CH09 reject pulp. By-pass of Diabolo 02DIA14 infeed. Accepted stock from Diabolo 02DIA14. Tertiary accept A3 from downstream ScreenOne 02SC19. Complement dilution water.

The level in Rejects chest 02CPA10 is controlled by LICS2395 and kept constant through control valve LCV-2395 on periodic filtrates from Pump 05PPC08.

Stage 2 Screen 02CH13:

Secondary Horizontal Screen 02CH13 is fed with pulp from pump 02PPC12 con-nected on Rejects chest 02CPA10.

Screen 02CH13 inlet and accept pressures are respectively measured by trans-mitters PIS2470 and PIS2480. Then differential pressure PdIS2485 is calculated and helps to check proper operation of Horizontal screen.

Stage 2 screening accepted pulp is routed in forward to Constant Level Box 02CP15 at a flow regulated with controller FFIC2500 whose set-point can be cal-culated in direct ratio with Primary screens accept flows and accordingly to an pre-set production repartition between primary and secondary stage.

After being diluted in line through On/Off valve AV-2490, Screen 02CH13 rejects are processed on last stage Diabolo 02DIA14.Flowmeter FI2460 continuously measures this reject flow.



Diabolo 02DIA14:

Diabolo 02DIA14 works in sequences, i.e., alternating working phases along with wash and contaminant removal phases (See Grafcet).

Diabolo 02DIA14 inlet and accept pressures are respectively measured by trans-mitters PIS2425 and PIS2415. Then differential pressure PdIS2430 is deduced and helps to check proper operation of the unit.

Over working phases, the unit is fed via valve AV-2450. The flow through the unit is adjusted by means of manual valve MV-2411, installed on the accept piping, connected to the unit’s top part.

The Diabolo accepts are sent backward to reject chest 02CPA10.

An eventual plugging of Diabolo basket will be detected by accept pressure low alarm PSL2415 and/or motor amp-load High pressure Alarm JISH2405. Then Di-abolo automatic sequence triggers Washing and dumping phases.

During the Dumping cycle (outside working phases), the stock sent to the Diabolo screen flows directly to Rejects chest 02CPA10 for a Dumping cycle duration of # 1-2 minutes over a working time of 5-30 minutes depending on the application. The flow is then adjusted (via a manual by-pass valve MV-2456) to the same value as accept flow over the working phase to avoid variations in the primary screen.

Diabolo rejects are flushed periodically.




HD Cleaners: 3 x LA250/3900Inlet flow 702 m3/h at consistency 3 to 3.8%.

Stage 1 Holes screens: 2 x Horizontal screen CH7Accept flow 420 m3/h at consistency 3%.Perforated holes of 1,2 mm

Stage 2 Holes screen: Horizontal screen CH7Accept flow 225 m3/h at consistency 2,7%.Perforated holes of 1,2 mm

Stage 3 Holes screen: Diabolo screen DT3Average accept flow: 85 m3/h at consistency 2-2,5 %Perforated holes of 1,4 mm

Screening Area nominal capacity: 450 BDT/24h (at CH accept).


1.12.1.1 High Density Cleaning



LICS 2005Constant level chest 02CPA01 level con-trol

5% 15% 85% 95% 0-70m3

NRC 2010 H.D. Cleaning feed consistency control 3 to 5%

PIS 2020H.D. Cleaners counter-pressure water pressure indication

3,5 0–10 Bars

PIS 2030H.D. Cleaner 02EPE04 feed pressure in-dication

2 4 0–5 Bars

PIS 2045H.D. Cleaner 02EPE04 accept pressure indication

1 3 0–5 Bars

PdIS 2050H.D. Cleaner 02EPE04 differential pres-sure indication

1,3 1,90–3 Bars

Software only


2 4 0–5 Bars


1 3 0–5 Bars


1,3 1,90–3 Bars

Software only

…/…






2 4 0–5 Bars


1 3 0–5 Bars


1,3 1,90–3 Bars

Software only

PIC 2125H.D. Cleaning stock outlet pressure con-trol

0–5 Bars

1.12.1.2 Holes screening



PIS 2305Primary Horizontal screen 02CH08 inlet pressure indication

1 3 3,5 0–5 Bars

PIS 2320Primary Horizontal screen 02CH08 ac-cept pressure indication

0,5 3 3,5 0–5 Bars

PdIS 2325Primary Horizontal screen 02CH08 differ-ential pressure indication

0,6 10–2,5 Bars

Software only

HIC 2330Primary Horizontal screen 02CH08 ac-cept flow command

0-100%

FI 2335Primary Horizontal screen 02CH08 ac-cept flow indication

0-250 m3/h

FFIC 2345Primary Horizontal screen 02CH08 re-jects flow control

0-100 m3/h

FSA 20160Primary Horizontal screen 02CH08 seal-ing water Low flow alarm

L Digital alarm

PIS 2355Primary Horizontal screen 02CH09 inlet pressure indication

1 3 3,5 0–5 Bars

PIS 2365Primary Horizontal screen 02CH09 ac-cept pressure indication

0,5 3 3,5 0–5 Bars

PdIS 2370Primary Horizontal screen 02CH09 differ-ential pressure indication

0,6 10–2,5 Bars

Software only

HIC 2380Primary Horizontal screen 02CH09 ac-cept flow command

0-100%

FI 2375Primary Horizontal screen 02CH09 ac-cept flow indication

0-250 m3/h

FFIC 2390Primary Horizontal screen 02CH09 re-jects flow control

0-100 m3/h

…/…





FSA 20165Primary Horizontal screen 02CH09 seal-ing water Low flow alarm

L Digital alarm

LICS 2395 Rejects chest 02CPA10 level control 5% 15% 85% 95% 0-20m3

PIS 2470Secondary Horizontal screen 02CH13 in-let pressure indication

1 3 3,5 0–5 Bars

PIS 2480Secondary Horizontal screen 02CH13 accept pressure indication

0,5 3 3,5 0–5 Bars

PdIS 2485Secondary Horizontal screen 02CH13 differential pressure indication

0,6 10–2,5 Bars

Software only

FFIC 2500Secondary Horizontal screen 02CH13 accept flow control

0-250 m3/h

FI 2460Secondary Horizontal screen 02CH13 re-ject flow indication

0-100 m3/h

FSA 20170Secondary Horizontal screen 02CH13 sealing water Low flow alarm

L Digital alarm

JISH 2405 Diabolo 02DIA14 drive Amp Load 95% 100% 0-150%

PIS 2425 Diabolo 02DIA14 inlet pressure indication 1 3 3,5 0–5 Bars

PIS 2415Diabolo 02DIA14 accept pressure indica-tion

0,5 3 3,5 0–5 Bars

PdIS 2430Diabolo 02DIA14 differential pressure in-dication

0,6 10–2,5 Bars

Software only

FSA 20175Diabolo 02DIA14 sealing water Low flow alarm

L Digital alarm




36- PULPED STOCK TRANSFER PUMP 01PPC17 TO HOLES SCREENING FEED CHEST LEVEL LICS2005

If Dump Tank Pump 01PPC17 is not running

Then Chest feed control valve LCV-2005 is forced closed.

37- HOLES SCREENING FEED CHEST LEVEL LICS2005 TO AGITATOR 02AG02

If Chest level LICS2005 is Low-LowThen Stop Agitator 02AG02

If Chest level LICS2005 is LowThen Inhibit Start Agitator 02AG02

If Chest level LICS2005 is not LowAnd Agitator 02AG02 in DCS Auto mode


38- INTERLOCKS TO HOLES SCREENING FEED PUMP 02PPC03

If Holes Screening Feed Chest level LICS2005 is Low-LowOr Stage 1 Horizontal screen 02CH08 is not runningOr Stage 1 Horizontal screen 02CH09 is not running

Then Holes screening feed pump 02PPC03 is stopped.

If Continuous Water pump 05PPC07 is not runningOr Booster water pump 02PPC07 is not runningOr Holes Screening Feed Chest level LICS2005 is Low

Then Inhibit start Holes screening feed pump 02PPC03

39- HOLES SCREENING FEED PUMP 02PPC03 TO SLAVE VALVE AV-2015

If Holes screening feed pump 02PPC03 is not runningThen Valve AV-2015 is forced closed (Hard interlock)

If Holes screening feed pump 02PPC03 is runningThen With on delay T=5s, Valve AV-2015 in Auto opens (air exhaust limit to

open 15s)



40- INTERLOCKS FROM HOLES SCREENING FEED PUMP 02PPC03

If Holes screening feed pump 02PPC03 is not running

Then Consistency controller NRC2010 is disabled with control valve NCV-2010 forced closed.

And HD Cleaners (02EPE04, 02EPE05 & 02EPE06) sequence is suspended.

The interlock is released when the pump is running with On-delay T=5s. In Auto, NRC2010 is then enabled; HD Cleaners sequences are ON proceed.

41- INTERLOCKS CONTINUOUS WATER PUMP 05PPC07 to HD CLEANERS FEED CONSISTENCY CONTROLLER NRC2010

If Continuous Water pump 05PPC07 is not running

Then Consistency controller NRC2010 is disabled With valve NRC2010 forced closed (Hard interlock)

42- HD CLEANER 02EPE04 TRAP TOP VALVE AV-2055 & TRAP BOTTOM VALVE AV-2060

If HD Cleaner 02EPE04 Trap Top Valve AV-2055 is not ClosedThen HD Cleaner 02EPE04 Trap Bottom Valve AV-2060 is forced Closed

If HD Cleaner 02EPE04 Trap Bottom Valve AV-2060 is not ClosedThen HD Cleaner 02EPE04 Trap Top Valve AV-2055 is forced Closed









45- INTERLOCKS to STAGE 1 SCREENS ACCEPT CONTROL VALVES

If Holes screening feed pump 02PPC03 is not runningOr Stage 1 Pre-Screen Holes 02CH08 is not running

Then Controller HIC2330 is disabled with valve HCV-2330 forced closed

If Holes screening feed pump 02PPC03 is not runningOr Stage 1 Pre-Screen Holes 02CH09 is not running

Then Controller HIC2380 is disabled with valve HCV-2380 forced closed

46- INTERLOCKS PERIODIC WATER PUMP 05PPC08 to REJECTS CHEST WA-TER CONTROL VALVE LCV-2395

If Periodic Water pump 05PPC08 is not running

Then Rejects chest level controller LICS2395 is disabled With valve LCV-2395 forced closed

47- REJECTS CHEST 02CPA10 LEVEL LICS2395 TO AGITATOR 02AG11

If Rejects chest level LICS2395 is Low-LowThen Stop Agitator 02AG11

If Rejects chest level LICS2395 is LowThen Inhibit Start Agitator 02AG11

If Rejects chest level LICS2395 is not LowAnd Agitator 02AG11in DCS Auto mode


48- INTERLOCKS TO SECONDARY SCREEN FEED PUMP 02PPC12

If Rejects chest level LICS2395 is LowOr Stage 2 Horizontal screen 02CH13 is not running

Then Secondary screen feed pump 02PPC12 is stopped.

If Continuous Water pump 05PPC07 is not runningOr Rejects chest level LICS2395 is Low

Then Inhibit start Secondary screen feed pump 02PPC12



49- SECONDARY SCREEN FEED PUMP 02PPC12 TO SLAVE VALVE AV-2397

If Secondary screen feed pump 02PPC12 is not runningThen Valve AV-2397 is forced closed (Hard interlock)

If Secondary screen feed pump 02PPC12 is runningThen With on delay T=5s, Valve AV-2397 in Auto opens (air exhaust limit to

open 15s)

50- INTERLOCKS to STAGE 2 SCREEN 02CH13 ACCEPT VALVES

If Secondary screen feed pump 02PPC123 is not runningOr Stage 2 Screen 02CH13 is not running

Then Accept ON/Off valve AV-2495 is forced closedAnd Flow controller FFIC2500 is disabled with valve FCV-2500 forced closed

51- TAILING SCREEN DIABOLO 02DIA14 FLUSHING

If Amp load JIS2405 is on alarm High for T=5 s

Then Blockage alarm is set to alarm (reset by operator acknowledge)And Diabolo Holes sequence is forced to Step Washing

52- TAILING SCREEN DIABOLO 02DIA14 INLET & REJECT VALVE

If Diabolo 02DIA14 reject valve AV-2435 is not Closed

Then Diabolo 02DIA14 inlet valve AV-2450 is forced Closed (Hard int.)

53- (RESERVE)

54- (RESERVE)

ALARMS

55- HD CLEANERS DILUTION WATER PRESSURE

If HD Cleaners dilution pump 02PPC07 is runningAnd Outlet pressure PIS2020 is on Alarm Low

Then Set HD Cleaners dilution pressure alarm



56- HORIZONTAL SCREEN 02CH08 SEALING WATER ALARM

If Stage 1 Pre-Screen Holes 02CH08 is runningAnd Sealing water flow FSA20160 is on Alarm Low

Then Set Stage 1 Pre-Screen Holes 02CH08 sealing water alarm

57- HORIZONTAL SCREEN 02CH09 SEALING WATER ALARM

If Stage 1 Pre-Screen Holes 02CH09 is runningAnd Sealing water flow FSA20165 is on Alarm Low

Then Set Stage 1 Pre-Screen Holes 02CH09 sealing water alarm

58- SECONDARY SCREEN 02CH13 SEALING WATER ALARM

If Secondary screen 02CH13 is runningAnd Sealing water flow FSA20170 is on Alarm Low

Then Set Secondary screen 02CH13 sealing water alarm

59- TAILING SCREEN DIABOLO 02DIA14 SEALING WATER ALARM

If Diabolo 02DIA14 is runningAnd Sealing water flow FSA20175 is on Alarm Low

Then Set Diabolo 02DIA14 sealing water alarm

60- REJECT CHEST 02CPA10 LEVEL HIGH-HIGH

If Rejects chest level LIC2395 is High-HighThen Active the ALARM

Note: This alarm doesn’t stop upstream screens 02CH08 & 02CH09 but Operator action is required to solve the problem that could lead to chest overflow.

61- SEALING WATER

If HD Cleaning & Holes Screening area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s




62- COMPRESSED AIR

If HD Cleaning & Holes Screening area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


63- (RESERVE)



1.14 OPERATION

1.14.1 Start-up

HD Cleaning & Holes screening area is to begin after Pulping.

1.14.1.1 Water filling.

Starting up the Pre-screening area begins with the filling phase of the units (refer to associated Function charts):

Basic conditions:- Sealing water main line is under pressure and Flow switch FSA20135 is not

alarm Low.- Compressed air system is under pressure (pressure PIA19202 not on Alarm

Low).- Loop 1 Clear Filtrate tank 05CE03 level LIS5055 is not Low.- Periodic water pump 05PPC08 must be running.- Continuous water pump 05PPC07 must be running.

Open sealing water valves: SV-19330 for St. 1 Horizontal Screen 02CH08. SV-19332 for St. 1 Horizontal Screen 02CH09. SV-19337 for St. 2 Horizontal Screen 02CH13. SV-19338 Diabolo 02DIA14.

Start of the cycle of the high density cleaners 02EPE04, 02EPE05 & 02EPE06 whose first step is the filling phase. (Dilution pump 02PPC07 start is obtained from HD Cleaners sequence).

Start of the cycles of Horizontal Screens 02CH08, 02CH09 and 02CH13, which each first step is the filling phase.

Start of Diabolo 02DIA14 cycle, whose first step is also the filling phase.

The units working in cycles (high density cleaners and Diabolo tailing screen) will automatically go over to the working configuration at the end of filling times.The filling time of the different units is controlled by delay times set on start-up of the installation. They take account of the size of units and of pressures and flow rates available in the water circuits.

1.14.1.2 Starting of the loop

Once the units are filled, the Pre-screening loop is enabled to start:

If dump chest 01CPA15 level is sufficiently filled with stock, start transfer pump 01PPC17 to fill Holes screening feed chest 02CPA01 up to 60%.

Start of Primary screens 02CH08 and 02CH09 motors.

Start of Holes screening feed pump 02PPC03.



As soon rejects chest 02CPA10 level has reached a minimum height (usually 40%):

Start of Secondary screen 02CH13 motor.

Start of Secondary screen feed pump 02PPC12.

NB 1: It is not necessary to wait for the end of Diabolo filling. Indeed, when it fills, its feed valve AV-2450 is shut, but its by-pass valve AV-2455 is open. The Pre screening loop can work, the rejects of Secondary screen 02CH13 will simply be sent directly into the rejects chest 02CPA10.

NB 2: Through interlocks, all regulation controllers will be enabled and will pro-ceed to Auto with associated equipment start-up.

1.14.2 Production

The process block can run few minutes in full recycling mode via constant level box 02CP15.

The stock is bled downstream of the constant level box 02CP15 when required by slots Pre-screening chest 02CPA16 level controller LIC2605.

1.14.3 OperationThe different steps run off automatically.To be monitored during the operation of the installation:- Correct course of cycles of the sequence-working units. In particular, whether

the time of working phases does correspond to the quantities of contaminants to be removed will have to be checked.

- Inlet and accepts pressures of cleaners and in the different screening stages.- Consistencies.- Flows through screening units.



1.14.4 Stop

Stop of Holes screening feed pump 02PPC03.

Stop of High-density cleaner cycles.

Stop of Primary screens 02CH08 and 02CH09 motors after a delay to flush the screen.

Stop of Secondary screen feed pump 02PPC12.

Stop of Secondary screen 02CH13 motor after a delay to flush the screen.

Stop of Diabolo 02DIA14cycle.

The working phases of the units with sequences discontinue bring their cycle to an end normally. They stop in idle position.

Note: After a shut during which the HD Cleaner have been emptied, the operator must fill up the HD Cleaner with the HD Cleaner sequence prior to start-ing Pump 02PPC03. Failure to do so may generate a pressure shock in the HD Cleaner piping and valve system.



PROCESS DESCRIPTION


PRINTING - WRITING

SLOTS PRE-SCREENING AREA

SLOTS PRE-SCREENINGPage 64/264


5 SLOTS PRE-SCREENING

1.15 DESCRIPTION

1.15.1 Area itemization

Slots Pre-screening feed chest................................................................................02CPA16

Fine screening feed agitator.....................................................................................02AG17

Fine screen feed pump.............................................................................02PPC18

Fine slots screen (ScreenOne).................................................................................02SC19

Accept constant level box.........................................................................................02CP20

1.15.2 ScreenOne basics

1.15.2.1 ScreenOne Description

ScreenOne is an integrated three stage screen. It is a self contained fine slot screening plant with a very low reject rate, energy consumption for a very low overall investment.

ScreenOne basically consists of a tank sealed with a cover and positioned vertic-ally. Inside there is a screen basket that allows the stock to be filtered as the res-ult of the action of a rotor.The rotor is supported and driven by a mechanism that is actuated by a belt drive.

Primary coarse screen (ScreenOne) connections: 1 inlet pipe 3 accept pipes 3 water dilution pipes 1 reject pipe 1 heavy rejects pipe (used as a drain) 1 sealing water inlet (to avoid eventual damage on internal elements).



1.15.2.2 ScreenOne operation

The pulp is fed from the bottom into the first stage, which is sized and designed to get the full use of the total basket length.

Thanks to Kadant’s new patented concept, the “Intermediate De-flocculation Device” with Dilution (ID3), the stage one reject reaches the second zone under ideal conditions to optimise the screening operation in 1terms of throughput and efficiency.

The same principle is applied with a second ID3 between the second and third zone. Thanks to ID3, separation between fiber and contaminants is extremely ef-ficient.

The screen cylinder is a multi-life rigid cage cylinder with easily removable ele-ments, allowing high flexibility in configuration.

The machine is fitted with a specifically designed rotor for high sticky removal and very low energy consumption.

1.15.2.3 ScreenOne sequence




1.15.3 Slots Pre-screening area

Stock flows by gravity from Holes Screening accept constant box 02CP15 up to feed chest 02CPA16 that is a constant level working chest.The level control LIC2605 commands the stock quantity required upstream the system via control valve LCV-2605 on stock feed pipe.

ScreenOne 02SC19 receives stock from pump 02PPC18 with stock at consist-ency 3-3,5% regulated by controller NRC2610 with control valve NCV-2610 on di-lution pipe fed with filtrates from Water tank 05CE03 via pump 05PPC07.

Pressure regulation loop PIC2705 (with control valve PCV-2705 on recirculating pipe back to feed chest 02CAP16) keeps constant ScreenOne feed pressure in order to avoid shocks (that could cause internal damages) during transitory phases (on ScreenOne start-up when automatic valve AV-2620 opens or during washing and unplugging sequences).We recommend inlet automatic valve AV-2620 to open slowly.

Transmitter PIS2640 continuously controls screen inlet pressure.

Accepted stock A1 (from first slotted screening zone) is routed to accept constant level box 02CP20.Flow can be adjusted by controller FIC2690 and pressure is continuously con-trolled by transmitter PIS2650.An accidental plugging will be detected by differential pressure alarm PDIS2645 (ratio between inlet and accept A1 pressures).

Rejects from this first zone are diluted (via manual valve MV-2626) with white wa-ter. This dilution flow is measured by loop FIC2625.

Accepted stock A2 (from second slotted screening zone) is also routed to Con-stant level box 02CP20.Flow is adjusted by controller FFIC2685 in ratio with accept A1 flow (FIC2690) and according to required reject rates between each screening zones.Stock pressure from accept A2 is continuously controlled by instrumentation loop PIS2660.An accidental plugging in 2nd screening zone will be detected by differential pres-sure alarm PDIS2655 (ratio between inlet and accept A2 pressures).

A water connection allows stock dilution between second and third screening zones. This dilution flow is indicated by loop FI2630 and may be adjusted at start-up with manual valve MV-2631.

Accepted stock A3 (from third slotted screening zone) is sent in backward pre-screening process:

Either to feed chest 02CPA16 through On/Off valve AV-2681. Or Holes reject chest 02CPA10 through On/Off valve AV-2682

Final pipe direction choice is to be made in order to stabilize ScreenOne feed consistency during stabilized operation.

A3 accept Flow is adjusted by controller FFIC2680 in ratio with accept A1 flow (FIC2690) and according to required reject rates between each screening zones.



Stock pressure from accept A3 is continuously controlled by instrumentation loop PIS2670.An accidental plugging in 3rd screening zone will be detected by differential pres-sure alarm PDIS2665 (ratio between inlet and accept A3 pressures).

Rejected stock from the third screening zone is also diluted before being directed to sewer.Reject dilution water flow is indicated by loop FI2635 and may be adjusted at start-up with manual valve MV-2636.

Stock rejected flow is adjusted by controller FFIC2675 in ratio with accept A1 flow (FIC2690) and according to required reject rates.

Dilution controller FIC2625 adds up all water dilution flows to ScreenOne and ad-justs the total (sum of measured flows FT-2625 + FT-2630 + FT-2635) according to operating dilution Set-Point (adjusted on start-up) by regulating opening value of control valve FCV-2625.The Low Flow Alarm for total water dilution calculations (i.e. measured total flow < 0,5 x set point) indicates a ScreenOne operation problem and is used to launch a Washing Sequence (see § 1.19.3.2 – Page 75).

In case of differential pressure alarm (for 1st screening zone, for the 2nd and for the 3rd) or in case of drive overload alarm (JISH2700), appropriate sequences are launched in order to clean the ScreenOne basket (See § 1.19.3 – Page 75).

Controller SIC2695 allows to adjust (manual set-point before start-up) and control speed of ScreenOne drive motor from DCS according to screen working condi-tions and then to save power consumption.

Stock outlet from constant level box 02CP20 is routed to downstream process (Pre-flotation).An overflow pipe from constant box 02CP20 to Feed chest 02CPA16 enables ScreenOne operation at constant rating (in flow and pressure), whatever the pro-duction variations.



1.16 BASIC OPERATION CAPACITY

ScreenOne: Size SO8- Area 1: Slots 0,20mm. Accept flow = ~550 m3/h at consistency 2,5-3%.- Area 2: Slots 0,18mm. Accept flow = ~120 m3/h at consistency 2-2,5%.- Area 3: Slots 0,20mm. Accept flow = ~30 m3/h at consistency 2%.

Total accept production (A1 + A2) = 430 BDT/24h




LICS 2605 Feed chest 02CPA16 level control 5% 15% 85% 95% 0-70 m3

NRC 2610Slots pre-screening feed consistency control

2,5 to 5%

PIC 2705ScreenOne 02SC19 feed pressure con-trol

0–4 Bars

FIC 2625 ScreenOne 02SC19 dilution flow control

FT-2625: intermediate dilution flow meas-urement (between 1st & 2nd zones)

0-100 m3/h

FC-2625: ScreenOne total water dilution flow controller

= (FT-2625 + FT-2630 + FT-2635)

L

(1)0-150 m3/h

FCV-2625: total dilution flow valve 0-150 m3/h

FI 2630ScreenOne 02SC19 intermediate dilution flow indication (between 2nd & 3rd screen-ing zones)

0-75 m3/h

FI 2635ScreenOne 02SC19 reject dilution flow indication

0-75 m3/h

PIS 2640ScreenOne 02SC19 inlet pressure indic-ation

3

(1)0–4 Bars

PdIS 2645ScreenOne 02SC19 differential pressure 1 indication

(Difference between Accept A1 & inlet)

0,4

(1)

0,6

(1)0–2 Bars

PIS 2650ScreenOne 02SC19 Accept A1 pressure indication

1

(1)0–4 Bars

…/…







0,4

(1)

0,6

(1)0–2 Bars


1

(1)0–4 Bars



0,4

(1)

0,6

(1)0–2 Bars


1

(1)0–4 Bars

FFIC 2675 ScreenOne 02SC19 reject flow control 0-50 m3/h

FFIC 2680ScreenOne 02SC19 Accept A3 flow con-trol

0-100 m3/h


0-250 m3/h

FIC 2690ScreenOne 02SC19 Accept A1 flow con-trol

0-750 m3/h

SIC 2695ScreenOne 02SC19 drive motor speed control

0-100%

JISH 2700 ScreenOne 02SC19 drive Amp Load 95% 100% 0-150%





64- SLOTS PRE- SCREENING FEED CHEST LEVEL LIC2605 TO AGITATOR 02AG17

If Slots Screening feed chest level LIC2605 is Low-LowThen Stop Agitator 02AG17

If Slots Screening feed chest level LIC2605 is LowThen Inhibit Start Agitator 02AG17

If Slots Screening feed chest level LIC2605 is not LowAnd Agitator 02AG17 in DCS Auto mode


65- INTERLOCKS TO FINE SCREENING FEED PUMP 02PPC18

If Slots Screening feed Chest level LIC2605 is LowOr ScreenOne 02SC19 is not runningOr Loop 1 Continuous water dilution pump 05PPC07 is not running

Then Screening feed pump 02PPC18 is stopped.

If Slots Screening feed Chest level LIC2605 is Low

Then Inhibit start of Screening feed pump 02PPC18

66- INTERLOCKS FROM SLOTS SCREENING FEED PUMP 02PPC18 TO SLAVE VALVE AV-2620

If Screening feed pump 02PPC18 is not running

Then On/Off slave valve AV-2620 is forced closed

67- INTERLOCKS TO CONSISTENCY CONTROL NRC2610

If Screening feed pump 02PPC18 is not runningOr Continuous water dilution pump 05PPC07 is not running

Then Consistency controller NRC2610 is disabled with control valve NCV-2610 forced closed.



68- (RESERVE)

69- (RESERVE)

ALARMS

70- SEALING WATER

If Slots Pre-screening area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


71- COMPRESSED AIR

If Slots Pre-screening area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


72- (RESERVE)



1.19 OPERATION

1.19.1 Start-up

Slots Pre-screening area is to begin after Holes screening area.

1.19.1.1 Fill the unit

Starting up the Slots Pre-screening loop begins with the filling phase of the unit:


alarm Low- Compressed air system is under pressure (pressure PIA19202 not on Alarm

Low).- Level control LIS5055 of water tank 05CE03 is not Low.

If not already running, start Loop 1 Continuous water pump 05PPC07.

Open ScreenOne sealing water valve SV-19342.

Start of ScreenOne cycle, whose first step is the filling phase (refer to specific Function Chart). :

Open reject valve FCV-2675 up-to its “X%" opening value. This posi-tion must allow water filling with a moderate pressure inside Screen-One.

Open water dilution valve FCV-2625 during a pre-set time (to be adjus-ted at start-up, usually 30 seconds).

Start of ScreenOne 02SC19 motor.

Note: The unit working in cycle automatically go over to the working configuration at the end of filling time (controlled by timer set on start-up of the installation and taking account of the size of the unit and of pressures and flow rates available in the water circuits).




Activation of level controller LIC2605 in order to fill feed chest 02CPA16 with pulp.

When a sufficiently level is reached (usually higher than 40%):

Start ScreenOne feed pump 02PPC18 with activation of pressure con-troller PIC2705.

Note 1: As long inlet valve AV-2620 is not open, pulp pumped by 02PPC18 flows back to feed chest 02CPA16 via control valve PCV-2705 fully open.Note 2: With interlocks, consistency controller NRC2610 is set on automatic.

Open slowly ScreenOne inlet valve AV-2620. Reject flow control loop FFIC2675 is activated (valve FCV-2675 moves

from full opening to operating value). Accept A3 flow control loop FFIC2680 is activated. Accept A2 flow control loop FFIC2685 is activated. Accept A1 flow control loop FFIC2690 is activated.

1.19.1.3 Production


DIP line Loop 1 starts in production when the stock is bled downstream of the constant level box 02CP20 to Pre-Flotation with opening of weight valve FCV-3020.

1.19.2 Operation

To be monitored during the operation of the installation: Inlet and accepts pressures of ScreenOne. All inlet and outlet consistencies. Regularity of flows through ScreenOne. Regularity of the power absorbed by the ScreenOne.



1.19.3 Sequences

This chapter hereunder is only for description.Please refer to associate Function Chart (to be supplied by Kadant) for exact se-quences to be programmed.

1.19.3.1 ScreenOne basket depluging

This sequence is launched in case of Differential pressure High alarm on threshold 1 (PDSH2645 for 1st screening zone, PDSH2655 for the 2nd and PDSH2665 for the 3rd) for T= 5 to 10 seconds.

Open reject valve FCV-2675 to its “X%" opening value. Close Accept control valve at screening stage in Alarm and Accept

control valve at eventual downstream stages.

Examples: On Alarm PDSH2665, cleaning of basket 3rd zone will close control valve

FCV-2680 for the 3rd stage.On Alarm PDSH2655, cleaning of basket 2nd zone will close control valves

FCV-2685 for the 2nd stage and valves FCV-2680 for the 3rd stage.On Alarm PDSH2645, cleaning of basket 1st zone will close control valves

FCV-2690 for the 1st stage, FCV-2685 for the 2nd stage and valves FCV-2680 for the 3rd stage.

After a pre-set timer (adjusted during start-up, usually 60 seconds): re-ject valve FCV-2675 and accept control valves come back to their automatic position.

1.19.3.2 ScreenOne washing

During ScreenOne normal operation, this sequence is launched in case of: An overload of the ScreenOne motor, detected by alarm JISH2700 for

T= 5 to 10 seconds. OR a differential pressure High-High alarm on threshold 2 (PDSHH2645

for 1st screening zone, PDSHH2655 for the 2nd and PDSHH2665 for the 3rd) for T= 5 to 10 seconds.

OR a Low alarm of total dilution water flow to ScreenOne (calculated by controller FC2625 < 0,5 x set point) during T=5 to 10s.

OR a ScreenOne stop request in AUTOMATIC mode. OR an Operator manual request (key “WASH”)

Close stock feed valve AV-2620. Close accept flow valves (FCV-2690 for accept A1, FCV-2685 for ac-

cept A2 & FCV-2680 for accept A3). Open reject valve FCV-2675 to its “X%" opening value. After a pre-set timer (usually 30 seconds), sequence proceeds either

back to working operation or to stop (if requesting in AUTO mode).



1.19.4 Shutdown

1.19.4.1 Stop of production

The process bloc stops in production when no more pulp required in downstream Flotation area, with closing of weight valve FCV-3020 on accept constant level box 02CP20 outlet pipe.

1.19.4.2 Stop of the loop

Please refer to associated function chart (will be supplied by Kadant) including “stop step” for ScreenOne:

A Washing sequence is launched (See § 1.19.3.2 – Page 75)At the end of this sequence, inlet valve AV-2620 remains closed and reject valve FCV-2675 remains to its “X%" opening value.

Stop feed pump 02PPC18 motor.With interlocks, consistency controller NRC2610 is disabled.

Closing (slowly with a ramp) of accept A1 valve FCV-2690. Closing (slowly with a ramp) of accept A2 valve FCV-2685. Closing (slowly with a ramp) of accept A3 valve FCV-2680. Stop of ScreenOne motor. Closing of water valve FCV-2625.



PROCESS DESCRIPTION


PRINTING - WRITING

PRE-FLOTATION AREA

PRE-FLOTATIONPage 77/264


6 PRIMARY FLOTATION

1.20 DESCRIPTION

1.20.1 Flotation Itemization

Prime MAC cell feed stand tube...............................................................................03CE12

Prime MAC cell 03CEV02a feed pump....................................................................03PPC01

Prime MAC cell ...........................................................................03CEV02a

Pre-flotation cell 03CEV02b 1st aeration feed pump...............................................03PPC03

Pre-flotation cell 03CEV02b 2nd aeration feed pump..............................................03PPC04

Pre-flotation cell 03CEV02b 3rd aeration feed pump...............................................03PPC05

Pre-flotation cell 03CEV02b 4th aeration feed pump...............................................03PPC06

Pre-Flotation cell (MAC)...........................................................................................03CEV02b

Pre-flotation accept constant level box.....................................................................03CP07

Foam tank (collecting compartment)........................................................................03CPA08

Recirculation foam pump to Prime MAC feed..........................................................03PPV10

Foam tank (definitive transfer compartment)............................................................03CPA09

Deinking foam transfer pump to treatment...............................................................03PPC11



1.20.2 Flotation cell (MAC) basics

The Flotation process consists of:

- An Aeration phase during which Air is introduced in the 1-1,4% consistency stock processed.This is done in the Auto-Clean Injectors, mounted in canisters-see figure be-low.

The size of canisters depending on the construction, their throughput will only de-pend on their inlet pressure. Each canister of injectors features:

A stock inlet, An outlet for the stock/air mix, A washing water inlet to fill the canister of injectors during start-up, shut-

down or washing, An inlet for air injected into the stock and also used for the discharge to

sewer of the washing water.

The size of air bubbles, the air percentage, and stock chemistry are important parameters.

- A Collection phase during which the ink or particles to be removed are col-lected by the air bubbles rising through the stock.

- A Separation phase, during which the air bubbles with the particles collected are separated from the stock.

- A Foam washing: water is injected at the top of deinking cell and flows back from 1st aeration outlet to 1st stage feed pump.

Collection and separation proceed in the Flotation cell.



1.20.3 Deinking MAC cell multi-Aeration flotation

Prime MAC cell with 3 stages in parallel

The 3/3 aerations Primary flotation cell (MAC) is composed of 3 superimposed elementary cells, each operating an Aeration phase, a Collection phase and a separation phase.

Fed by a common pump, the processed stock is processed successively in the 3 parallel cells.

Stock accepted from each cell is collected in a common level tank at the top of the cell maintaining the cell slightly pressurized.

Deinking MAC cell with 4 stages in cascade

The 4 aerations Primary flotation cell (MAC) is composed of 4 superimposed ele-mentary cells, each operating an Aeration phase, a Collection phase and a sep-aration phase (See above).

The processed stock is processed successively in the 4 cells.

The stock is pumped through the first aeration injectors to the first cell, disposed on the top of the cell. The stock accepted from the first cell is pumped through the Second aeration injectors, until the last cell accept flows to a constant level box.

The Air separated from each elementary cell rises through the stock flow feeding the previous cell, leading to a full counter-current flow of air relatively to the fiber flow.

The constant level box maintains the cell slightly pressurized.

Deinking foam

The Flotation Foam (separated Air bubbles with collected particles) is blown out via a control valve under action of the cell pressure. By its mechanical action on the foam, the control valve allows a good air-liquid separation of the foam in the foam tank.

The Foam control valve is used to control the Foam level in the cell, and by this, to control the operating conditions of the cell (quantity of foam).

The foam control valve is the main control on the operating conditions of the cell: Foam consistency, Ash content in Foam, Brightness & speck elimination, loss control in Total solids and Fiber-see figure below.

1.20.4 Deinking cell MAC Sequence




1.20.5 Pre-Flotation area

1.20.5.1 Prime MAC 03CEV02a

Prime MAC cell feed

The stock coming from the constant level box 02CP20 is pumped to flotation cell MAC through 1st aeration pump 03PPC01 connected on water tank 05CE02 to ensure necessary dilution.

Flowmeter FIC3020 adjusts flotation stock feed flow.Control valve FCV-3020 is the basis weight valve for 1st loop of deinking line: its opening fixes the production rate of Loop 1.

As transmitter NI3015 also continuously measures consistency at this point, then instantaneous Loop 1 production (P1-3015) can be calculated and checked (and corrected if necessary through FIC3020 set-point) by operator.

A chemicals injection (surfactant), connected at pump 03PPC01 suction, allows adjusting flotation operation according to process conditions and required effi-ciency.

Pump 03PPC01 feeds the 3 parallel canisters of injectors, at the pressure re-quired (1,4 bars normally) to ensure air suction and mixing of bubbles in the stock. Manual valve MV-3021 at the pump discharge is meant to adjust the inlet pres-sure and thus the operating flow of the cell.Inlet pressure of each injectors canister are measured by transmitters PIS3065, PIS3085 and PIS3105. Then eventual problems can be more easily detected.

The canister’s washing water connection nipples have automatic isolating valves used during the various operating sequences.

Stock aerated in this way flows inside the cell where separation of air bubbles from the stock takes place.

Prime MAC accept stock

Stock accepted from each stage flow to a common tank on top of the cell and from where pump 03PPC03 directly connected on outlet pipe feeds flotation cell 03CEV02b.

In order to balance Prime MAC 03CEV02a stock accept flow and Deinking cell 03CEV02b feed flow, an overflow outlet sends stock excess flow back to Prime MAC feed pump 03PPC01 suction, through a stand tube 03CE12 used to avoid air suction into pump 03PPC01.Stand Tube 03CE12 is equipped with a water injection (through On/Off valve AV-3136) in order to break foam bubbles that could eventually pile-up there.



Prime MAC cell foam

Foam level is regulated by level controller LIC3145 together with pressure trans-mitters LT1-3145, LT2-3145 and PT3150 (refer to regulation principle in Kadant Function Charts).

The cell level means the stock level in the cell, i.e., the position of the interface between the stock (at the lower part) and the foam (at the top part).

Foam from the flotation at each aeration stage flows together in the cell’s top part to fill it entirely.

Prime MAC is equipped with a foam washing device, allowing to “wash” ink foam collected at cell top part and then to regulate deinking losses with washing flow controller FIC3135.

Foam tank 03CPA09

Foam is discharged through piping from cell top part. This piping is fitted with control valve LCV-3145, ensuring both level control in the cell and relaxing of foam, which is thus discharged as liquid to sludge tank 03CPA09 and transferred to treatment (outside DIP line) through foam pump 03PPC11.

Pump 03PPC11 is equipped with a variable speed motor in order to adapt foam transfer flow to Foam tank 03CPA08 level LICS3155.Moreover, as foam flow to be transferred can vary in a large margin (not easily compatible with a standard pump curve flow/pressure), pressure regulation loop PIC3160 (with control valve PCV-3160 on recirculating pipe back to foam tank 03CPA09) helps for this recirculation when flow to be transferred is lower.

Principle:Foam pump 03PPC11 operating range flow is between a limited margin (could be between 50 to 100% design flow).In case all foam flow extracted from pre-flotation cell 03CEV02b is recirculated to Prime MAC feed pump 03PPC01 (via pump 03PPV10). Then tank 03CPA09 re-ceives only foam from Prime Mac cell 03CEV02a and pump 03PPC11 has to transfer a lower flow (could be less then 50% of pump 03PPC11 design flow).In order to maintain level in Foam tank, level controller LICS3150 will enable pressure controller PIC3160 with opening of valve PCV-3160 in parallel with reg-ulation to pump motor speed control SC3155.

In case tank 03CPA09 receives foam flow extracted from Prime Mac cell 03CEV02a and from pre-flotation cell 03CEV02b and if flow to be transferred to treatment is acceptable for pump 03PPC11 design curve, then level controller LICS3150 will regulate tank 03CPA09 level with pump motor speed control SC3155 (and pressure controller PIC3160 can be disabled with closing of valve PCV-3160).



Foam tank 03CPA08 and foam recirculation to Prime MAC

The main benefit of Prime MAC use is the opportunity to re-introduce a part or the totality of DIP line deinking foam and micro-flotation sludge, in order to reduce fiber losses and increase plant yield.Of course this re-introduction flow must be adjustable in relation with required pulp final quality.

Tank 03CPA08 receives:- Totality of foam flow extracted from pre-flotation cell 03CEV02b.- A part or totality of micro-flotation sludge flow transferred by pump 13PPC16

and according to adjustment of recirculation flow control FIC14085 (see § 1.70.3.2 - Micro-flotation – Page 256).

Note: Post-Flotation foam recycled flow is sent directly to Prime MAC feed pump 03PPC01 suction.

Volumetric pump 03PPV10 transfers foam to be reintroduced from tank 03CPA08 to Prime MAC feed pump 03PPC01.Operator gives set-point of this transfer flow through pump motor speed controller SC3125. (One main characteristic of a volumetric pump is that motor speed is dir-ectly proportional to delivery flow. Then transfer flow is obtained with pump curve and motor speed value).

Recirculated foam can be re-introduced either at pump 03PPC01 suction (through On/Off valve AV-3028) or at outlet (through On/Off valve AV-3027). Fi-nal choice to be done according to piping installation and resulting pressures available in the circuit).

Foam tank 03CPA08 level is controlled by LICS3150 in order to stop extraction pump 03PPV10 in case of Low level.

In case recirculated foam flow (set through pump 03PPV10) is nil or lower than foam extracted from Cell 03CEV02b, excess flow overflow to tank 03CPA09 and is pumped by 03PPC11 to sludge treatment.

1.20.5.2 Primary flotation cell MAC 03CEV02b

The stock accepted from Prime MAC 03CEV02a is pumped to flotation cell MAC 02CEV02b through 1st aeration pump 03PPC03.

1st aeration pump 03PPC03 feeds canister of injectors of the cell’s first stage, at the pressure required (1,4 bars normally), and continuously measured by trans-mitter PIS3365, to ensure air suction and mixing of bubbles in the stock. Manual valve MV-3372 at the pump discharge is meant to adjust the inlet pres-sure and thus the operating flow of the cell.

Stock aerated in this way flows in the first stage in the top of the cell where separ-ation of air bubbles from the stock takes place.



Multi-aeration principle

Stock is then taken up in a pipe in the central barrel to flow out at the cell’s lower part so as to feed the 2nd aeration.

2nd aeration pump 03PPC04 feeds 2nd canister of injectors, identical to the previ-ous one.Hand valve MV-3353 at the pump discharge enables to adjust the inlet pressure of the 2nd aeration canister of injectors (pressure is continuously measured by transmitter PIS3345). Stock flows in the cell at a level lower than the one of the previous stage.

Stock will circulate in the same way for the subsequent aeration steps:- 3rd aeration pump 03PPC05 (with inlet pressure meas-ured by PIS3325).- 4th aeration pump 03PPC06 (with inlet pressure meas-ured by PIS3305).

Accept constant level box

After the last aeration stage at the lower part of the cell, stock goes up to con-stant level box 03CP07 at a higher level than the top of the cell. Thus the cell is statically and steadily pressurized and floated stock flows out freely.

From this constant level box, stock is routed by gravity to a further process stage.Constant level box can also send the stock back to the suction of prime MAC feed pump 03PPC01.This recycling flow is adjusted by HIC3005 during normal operation (where recir-culating flow is to be set between 0 and 15% maxi of Flotation design flow).Moreover a parallel bigger pipe, equipped with On/Off Valve AV-3006, allows to recirculate back all flotation accept flow from constant box 03CP07 if needed by a transitory phase (for example adjustment on start-up or an eventual incident).

This configuration of circuit enables Flotation operation at constant rating, whatever the production in downstream process.

The flow through injectors being set by the inlet pressure required for their proper operation, the flow through the cell is firm.

Due to its principle and inner construction, the Primary flotation cell (MAC)’s pro-duction is only fixed by the feed pump. The other aeration pumps can run or be turned off without affecting the production flowing through the cell. They only af-fect stock quality insofar as their role is just limited to aerating stock via the inject-ors.

Deinking cell 03CEV02b foam

MAC cell 03CEV02b foam level is regulated by level controller LIC3390 with PIS3390 (refer to regulation principle in Kadant Function Charts).The cell level means the stock level in the cell, i.e., the position of the interface between the stock (at the lower part) and the foam (at the top part).




Foam is discharged through piping at the cell’s lower part. This piping is fitted with control valve LCV-3390, ensuring both level control in the cell and relaxing of foam, which is thus discharged as liquid to sludge tank 03CPA08.




Prime MAC cell: MAC3/3W1488Inlet flow 1488 m3/h at consistency 1,35% (i.e. 480

BDMT/24h)

Primary flotation MAC cell 4 aerations: MAC4A1456


1.22.1 Prime MAC 03CEV02a



HIC 3005Control of deinking cell 03CEV02B ac-cept recycling

0-100%

NI 3015 Flotation feed consistency indication 2 to 5%

FIC 3020 Flow control of stock sent to flotation 0-700 m3/h

P1 3015DIP line Loop 1 production indication

(Calculation with NI3015 & FIC3020)Software only

PIS 3065Prime MAC 03CEV02a inlet 1 pressure indication

1 2 0–3 Bars


1 2 0–3 Bars


1 2 0–3 Bars

FIC 3135Flow control of Prime MAC cell foam washing water

0-75 m3/h

PIS 3145Prime MAC 03CEV02a inside pressure indicator

1 0–3 Bars

LIC 3145Prime MAC 03CEV02a inside foam level control

0-100%

LIC 3150 Foam tank 03CPA08 level control 5% 15% 85% 95% 0-30m3

SC 3125Foam recirculating pump 03PPV10 motor speed control

0-100%


SC 3155Foam transfer pump 03PPC11 motor speed control

0-100%

PIC 3160Foam transfer pump 03PPC11 outlet pressure control

0–4 Bars



1.22.2 Primary flotation cell MAC 03CEV02b



PIS 3365Pre-flotation cell 03CEV02b Stage 1 feed pressure indication

1 2 0–3 Bars


1 2 0–3 Bars


1 2 0–3 Bars


1 2 0–3 Bars

PIS 3390Pre-flotation cell 03CEV02b inside pres-sure indicator

1 0–3 Bars

LIC 3390Pre-flotation cell 03CEV02b inside foam level control

0-100%




73- INTERLOCKS to PRIME MAC FEED PUMP 03PPC01

If Water tank 05CE02 level controller LIS5045 is lowOr Prime MAC cell inside pressure is High (LIC3145 level High)

Then Prime MAC feed pump 03PPC01 is stopped.

74- PRIME MAC FEED PUMP 03PPC01 to DEINKING CELL LEVEL CONTROL-LERS PIS3145 & LIC3145

If Prime MAC feed pump 03PPC01 is not running

Then Controllers PIS3145 & LIC3145 are disabled with LCV-3145 forced open.

75- PRIME MAC FEED PUMP 03PPC01 to SLAVE ON/OFF VALVE AV-3022

If Prime MAC feed pump 03PPC01 is not runningThen On/Off Valve AV-3022 is forced closed

If Prime MAC feed pump 03PPC01 is runningThen With on delay T=5s, On/Off Valve AV-3022 in Auto is opened (air ex-

haust limit to open 15s)

76- OTHER INTERLOCKS from PRIME MAC FEED PUMP 03PPC01

If Prime MAC feed pump 03PPC01 is not running

Then Stock feed control valve FCV-3020 is forced closedAnd Flotation accept constant box 03CP07 recycling control valve HCV-3005

and On/Off Valve AV-3006 are forced closedAnd Pre-flotation foam recirculating pump 03PPV10 is forced stoppedAnd On/Off valve AV-3140 on Post-flotation foam recirculating pipe is forced

stopped (if running, all post-flotation foam flow to sludge treatment with pump 09PPV07).

And Chemicals supply to feed pump suction is disabledAnd On/Off Valve AV-3022 (at pump outlet) is forced closed

77- FOAM TANK 03CPA08 LEVEL LICS3150 to EXTRACTION PUMP 03PPV10

If Foam tank 03CPA08 level LICS3150 is Low

Then Stop foam recycling pump 03PPV10



78- SECURITY INTERLOCKS FROM VOLUMETRIC PUMP 03PPV10 TO OUTLET ON/OFF VALVES

If On/Off valve AV-3027 is not open (Open limit switch not activated)Then On/Off valve AV-3028 is not allowed to Close

If On/Off valve AV-3028 is not open (Open limit switch not activated)Then On/Off valve AV-3027 is not allowed to Close

If On/Off valve AV-3027 is closedAnd On/Off valve AV-3028 is closed

Then Volumetric pump 03PPV10 is forced stopped

79- FOAM TANK 03CPA09 LEVEL LICS3155 to EXTRACTION PUMP 03PPC11

If Sludge tank 03CPA09 level LICS3155 is Low

Then Stop sludge transfer pump 03PPC11

80- FOAM PUMP 03PPC11 to REGULATIONS ON DELIVERY PIPE

If Foam transfer pump 03PPC11 is not running

Then Outlet pressure controller PIC3160 is disabled with valve PCV-3160 forced closed.

And Control valve LCV-3155 (on delivery pipe) is forced closed

81- CELL 03CEV02b 1st AERATION FEED PUMP 03PPC03 to DEINKING CELL LEVEL CONTROLLERS PIS3390 & LIC3390

If 1st aeration pump 03PPC03 is not running

Then Controllers PIS3390 & LIC3390 are disabled with LCV-3390 forced open.

82- CELL 03CEV02b 1st AERATION FEED PUMP 03PPC03 to SLAVE ON/OFF VALVE AV-3373

If 1st aeration pump 03PPC03 is not runningThen On/Off Valve AV-3373 is forced closed

If 1st aeration pump 03PPC03 is runningThen With on delay T=5s, On/Off Valve AV-3373 in Auto is opened (air ex-




83- INTERLOCKS to CELL OTHER AERATION FEED PUMPS


Then 03PPC04 is forced stopped (2nd Aeration)Then 03PPC05 is forced stopped (3rd Aeration)Then 03PPC06 is forced stopped (4th Aeration)

If Deinking Cell level LIC3390 is Low (meaning Cell inlet pressure is High)

Then Inhibit start of pump 03PPC04 (2nd Aeration)Then Inhibit start of pump 03PPC05 (3rd Aeration)Then Inhibit start of pump 03PPC06 (4th Aeration)

84- (RESERVE)

85- (RESERVE)

ALARMS

86- SEALING WATER

If Pre-Flotation area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


87- COMPRESSED AIR

If Pre-Flotation area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


88- (RESERVE)



1.24 OPERATION

1.24.1 Start up

1.24.1.1 Water filling



Low).- Prime MAC cell 03CEV02a foam valve LCV-3145 must be open- Pre-flotation cell 03CEV02b foam valve LCV-3390 must be open

Water tank 05CE02 level controller LIS5045 must be highStock valve FCV-3020 is closedRecycling valve HCV-3005 is closed

Prime MAC 03CEV02a filling:

Vent valve AV-3165 on the top of the Prime MAC cell is normally open. Start Prime MAC feed pump 03PPC01. (With Interlocks valve AV-3022

after T=5 sec). Water valves AV-3120, AV-3100 and AV-3080 (on parallel canisters of

injectors) open during T=15 sec and close.

When the cell is full, detected by level controller LIC3145 High:

Primary flotation cell MAC 03CEV02b filling:

Vent valve AV-3385 on the top of the deinking cell is normally open. Start 1st aeration pump 03PPC03. (With Interlocks valve AV-3373 after

T=5 sec). Water valve AV-3380 of the 1st stage canister of injectors opens dur-

ing T=15 sec and closes.

When the cell is full, detected by level controller LIC3390 High: Close vent valve AV-3385 on the top of the deinking cell 03CEV02b. Stop 1st aeration pump 03PPC03. (With Interlocks valve AV-3373

closes automatically). Close vent valve AV-3165 on the top of the Prime MAC cell. Stop Prime MAC feed pump 03PPC01. (With Interlocks valve AV-3022

closes automatically).



1.24.1.2 Starting of loop

Prime MAC 03CEV02a start:

Start Prime MAC feed pump 03PPC01. (With Interlocks valve AV-3022 after T=5 sec).

Open air valves AV-3115, AV-3095 and AV-3075 for Prime MAC. Water valves AV-3120, AV-3100 and AV-3080 (of the parallel canisters

of injectors) open during T=15 sec and close. Set to AUTO mode Prime MAC cell level regulation LIC3145.

Primary flotation cell MAC 03CEV02b start:

Aeration 4: Start 4th aeration feed pump 03PPC06 Open air valve AV-3315 for 4th aeration of cell 03CEV02b Water valve AV-3320 of the 4th stage canister of injectors opens dur-


Aeration 3: Start 3rd aeration feed pump 03PPC05 Open air valve AV-3335 for 3rd aeration of cell 03CEV02b Water valve AV-3340 of the 3rd stage canister of injectors opens dur-


Aeration 2: Start 2nd aeration feed pump 03PPC04 Open air valve AV-3355 for 2nd aeration of cell 03CEV02b Water valve AV-3360 of the 2nd stage canister of injectors opens dur-


Aeration 1: Start 1st aeration feed pump 03PPC03 Open air valve AV-3375 for 1st aeration of cell 03CEV02b Water valve AV-3380 of the 1st stage canister of injectors opens dur-


Set to AUTO mode flotation cell 03CEV02b level regulation LIC3390



1.24.1.3 Production

Foam transfer pump 03PPC11 can start (if allowed through interlocks)

Set to AUTO mode: flotation stock feeding flow controller FIC3020.

Deinking foam washing controller FIC3135 can be set in Auto (flow set-point to be adjusted according to desired Fiber content in deinking foam) after a timer to be pre-set before start-up.

Set in “AUTO” mode foam tank 03CPA08 level controller LICS3150.If required (for example through a specific mode “With Pre-flotation foam recircu-lation” selected), start of foam recirculation pump 03PPV10 (with motor speed SC3125 at the pre-set value).

1.24.2 Operation

Monitoring of inlet pressures within the canisters of injectors.Monitoring of consistencies of inlet stock, accept stock and deinking foam for each cell.

Regularly at a rate that will be determined by the operation: Open level control valves LCV-3145 and LCV-3390 to raise the level

within each cell and clean the upper part of the cell. This operation will last a few seconds after which level controller will take its normal course of operation.

Flush each canister of injectors successively, for a few seconds, against possible stock deposits.



1.24.3 Stop

1.24.3.1 Stop of loop

If required (for example through a specific mode “With Pre-flotation foam recircu-lation” selected), stop of foam recirculation pump 03PPV10.

Disable foam washing flow controller with closing of valve FCV-3135.

Close the Flotation feed stock valve FCV-3020 at the outlet of constant level box 02CP20.

1.24.3.2 Stop of the Deinking cells

Execute the washing sequences for each injectors canister on both deinking cells (Prime MAC 03CEV02a and flotation cell 03CEV02b) (on operator order).

Primary flotation cell MAC 03CEV02b stop:

Aeration 1: Close air valve AV-3375 for 1st aeration of cell 03CEV02b. Water valve AV-3380 on canister of injectors opens during T=15 sec

and closes. Stop 1st aeration feed pump 03PPC03

Set to MANU mode flotation cell 03CEV02b level regulation LIC3390 and open fully foam valve LCV-3190.

Open vent valve AV-3385 on the top of the deinking cell.

Aeration 2: Close air valve AV-3355 for 2nd aeration of cell 03CEV02b Water valve AV-3360 on canister opens during T=15 sec and closes. Stop 2nd aeration feed pump 03PPC04

Aeration 3: Close air valve AV-3335 for 3rd aeration of cell 03CEV02b Water valve AV-3340 on canister opens during T=15 sec and closes. Stop 3rd aeration feed pump 03PPC05

Aeration 4: Close air valve AV-3315 for 4th aeration of cell 03CEV02b Water valve AV-3320 on canister opens during T=15 sec and closes. Stop 4th aeration feed pump 03PPC06



Prime MAC 03CEV02a stop:

Close air valves AV-3115, AV-3095 and AV-3075 for Prime MAC. Water valves AV-3120, AV-3100 and AV-3080 (on parallel canisters of

injectors) open during T=15 sec and close. Stop Prime MAC feed pump 03PPC01. (With Interlocks valve AV-3022

after T=5 sec).

Set to MANU mode Prime MAC cell 03CEV02a level regulation LIC3145 and open fully foam valve LCV-3145.

Open vent valve AV-3165 on the top of the Prime MAC cell.



PROCESS DESCRIPTION


PRINTING - WRITING

FINE CLEANING

CLEANINGPage 96/264


7 CLEANING

1.25 DESCRIPTION

1.25.1 Area Itemization

Cleaners 1st stage – Canister 1................................................................................04CLR04A

Cleaners 1st stage – Canister 2................................................................................04CLR04B

Cleaners feed pump stage 2....................................................................................04PPC05

Cleaners 2nd stage .............................................................................04CLR06


Cleaners 3rd stage .............................................................................04CLR08


Cleaners 4th stage .............................................................................04CLR10

1.25.2 Basics Cleaners System

1.25.2.1 Cleaners description

Kadant ELP Cleaners

The Kadant ELP Cleaners are cyclonic cleaners, which remove by centrifuge ef-fect HEAVY particles from a dilute (<1%) stock flow.

The stock is introduced into the Cleaner through the cleaner head with an integ-rated spiral deflector, which impels a rotating movement to the stock flow. The heavy particles are centrifuged against the wall of the cleaner, and, due to the shape of the conical cleaner wall, progress towards the REJECT end of the cleaner.

Multi-stage systems

The Reject flow obtained on one stage with optimal reject elimination contains fiber, which must be recovered.

The Cleaners are therefore assembled is successive stages. Each stage rejects flow to the next stage; each stage accepts flow back to the previous stage. The

CLEANINGPage 97/264


consistency of the stock decreases from one stage to the next, with successive dilutions at the feed of each stage.

CLEANINGPage 98/264


Canister/Battery assembly

For the high number of cleaners ELP136 required in the 1st/2nd/3rd stages for a high efficiency cleaning, an optimal mounting arrangement of the cleaners is in Canisters. The Feed to the cleaners flows though the Inlet compartment. The Ac-cepts and Rejects flow through the Accept and the Reject compartment.

The reject flow is diluted in the Reject compartment by a manually set filtrate flow.

The last stage is composed of ELP440 cleaners mounted in bank, with common Inlet, Accepts and Rejects headers.

1.25.2.2 Cleaners operation

A cleaner is characterized by its pressure loss curve against flow in given condi-tions: for adequate operation, the pressure differential across the cleaners is 15 mWC.

On start-up, the manual valves on the Cleaner feed pumps, Accept lines and Re-ject lines will be set as to obtain the adequate differential pressure on all Cleaner stages.

CLEANINGPage 99/264

I n l e t A c c e p t

R e je c t

ELP 136 Canister Assembly


Where these settings are implemented with control valves, the adequate control valve positions are memorized as fixed opening set-point in the DCS.In operation, operator on DCS monitors the differential pressures on all cleaner stages. The Cleaner settings do not change in normal operation.

ATTENTION: In operation, deviation on any stage of the Cleaner differential pres-sure required to obtain an adequate Cleaner differential pressure indicate either 1) a modification of the Cleaner manual valve settings, 2) a plugging on a certain number of cleaners.

This may result in sub-optimal operation of the Cleaner system, with increase in stock Cleaning consistency and stock back-flows to the Filtrate tank.

The operator is to control these deviations to ensure the operation of the Cleaner system remains optimal.

The manual valve settings should not be modified without a proper verification that the operating conditions obtained are adequate.

1.25.3 Cleaners system sequence


CLEANINGPage 100/264


1.25.4 Area description

The 4-Stage Cleaners System consists in 3 of ELP136 canisters and 1 bank of ELP440 (for last stage).

Desaeration Chest 04CPA01

Stock accepted from Pre-Flotation is accepted by gravity from Level Box 03CP07 into Desaeration chest 04CPA01.

Desaeration chest 04CPA01 is operated at constant level via level controller LICS4005 with control valve LCV-4005 on water addition pipe provided by Loop 1 Periodic Clarified pump 05PPC08.A parallel filtrate pipe with a bigger diameter is used for chest filling on start-up.Filling On-Off valve AV-4006 is also interlocked with level controller LICS-4005.

Desaeration chest 04CPA01 allows the air remaining in stock pulp to escape and is equipped with an agitator 04AG02.

Cleaners are of hydro-cyclone type and must always run at their design flow. The battery’s inlet and accept are fitted with manual control and with pressure meas-uring for adjusting the operating flow rate and detect any variation.

Stage 1 Cleaners 04CLR04A & 04CLR04B

Stage 1 Cleaners is composed of 2 identical and parallel canisters 04CLR04A & 04CLR04B.

Stage 1 Cleaners pump 04PPC03 feeds dilute stock to Stage 1 Cleaners, with On/Off valve AV-4110 operating as slave valve to the pump.

The following pressures are obtained from instruments mounted on Canister and connected pipes:For canister 04CLR04A:- Inlet Pressure PIS4030- Accept Pressure PIS4020.- Differential pressure 1 PDIS4035 (calculated by DCS from difference

between inlet and accept pressure).- Rejects Pressure PIS4045.- Differential pressure 2 PDIS4050 (calculated by DCS from difference

between inlet and reject pressure).

For canister 04CLR04B:- Inlet Pressure PIS4080- Accept Pressure PIS4070.- Differential pressure 1 PDIS4085 (calculated by DCS from difference



1st stage Cleaners Reject feed the second stage of Cleaners.



The Stage 1 reject dilution flow is set on start-up by manual valves on top of each canister, switched on by common On/Off valve AV-4215 on Loop 1 Continuous filtrates.

The Stage 1 Sealing chamber degassing valves AV-4060 (for canister 04CLR04A) and AV-4105 (for canister 04CLR04B) open on start of feed pump 03PPC03, and closes after 30s.

1st stage Cleaners accepted stock directly feeds downstream Loop 1 Disc Filter at the required pressure.

To maintain differential pressure on stage 1 Cleaners in different hydraulic condi-tions, regulation loop PIC4010 controls the accept pressure with 2 control valves PCV-4010A and PCV-4010B on 2 parallel recirculation pipes to Cleaners feed pump 04PPC03 suction:- The smallest diameter valve PCV-4010A will be enabled with controller

PIC4010 during normal operation (when pressure recirculation flow not ex-ceeds 120m3/h).

- The biggest diameter valve PCV-4010B will be used during transitory phases (like start-up) requiring a bigger pressure recirculation (even a total recircula-tion).

This configuration of circuit enables Cleaners system operation at constant rating, whatever the production. Malfunctions or possible problems are thus more easily detected.

Stage 2 Cleaners 04CLR06:

Stage 2 Cleaners pump 04PPC05 feeds dilute stock to Stage 2 Cleaners 04CLR06, with On/Off valve AV-4160 operating as slave valve to the pump.

The following pressures are obtained from instruments mounted on Canister and connected pipes:- Inlet Pressure PIS4130- Accept Pressure PIS4120.- Differential pressure 1 PDIS4135 (calculated by DCS from difference



2nd stage Cleaners Accept flow back to Stage 1 pump 04PPC03 suction

2nd stage Cleaners Reject feed the third stage of Cleaners.

The Stage 2 reject dilution flow is set on start-up by manual valve MV-4156 on top of canister.

The Stage 2 Sealing chamber degassing valve AV-4155 opens on start of feed pump 04PPC05, and closes after 30s.




Stage 3 Cleaners pump 04PPC07 feeds dilute stock to Stage 3 Cleaners 04CLR08, with On/Off valve AV-4210 operating as slave valve to the pump.

The following pressures are obtained from instruments mounted on Canister and connected pipes:- Inlet Pressure PIS4180- Accept Pressure PIS4170- Differential pressure 1 PDIS4185 (calculated by DCS from difference

between inlet and accept pressure).- Rejects Pressure PIS4195- Differential pressure 2 PDIS4200 (calculated by DCS from difference


3rd stage Cleaners Accept flow back to Stage 2 pump 04PPC05 suction

3rd stage Cleaners Reject feed the last stage of Cleaners.

The Stage 2 reject dilution flow is set on start-up by manual valve MV-4206 on top of canister.

The Stage 3 Sealing chamber degassing valve AV-4205 opens on start of feed pump 04PPC07, and closes after 30s.


Stage 4 Cleaners pump 04PPC09 feeds dilute stock to Stage 4 Cleaners 04CLR10. On/Off valve AV-4220 operates as slave valve to the pump.

The following pressures are obtained:- Inlet Pressure PIS-4250- Accept Pressure PIS-4235- Differential pressure PDIS4255 (calculated by DCS from difference between

inlet and accept pressure).

4th stage Cleaners Accept flow back to Stage 3 pump 04PPC07 suction.

The Stage 4 reject dilution flow is set on start-up by manual valve MV-4224 and switched on by On/Off valve AV-4225 on Fresh Water line.

Common Stages 1-4 Cleaners

The suctions of Cleaners feed pumps 04PPC05 (stage 2), 04PPC07 (Stage 3) and 04PPC09 (Stage 4) are connected to Loop 1 Clear Filtrate tank 05CE03, whose constant level ensures a constant head on the pumps and the dilution of the successive stock flows between each stage. Low level LIS5055 alarm will stop the pumps.



The dilution flow to Rejects compartment of Stages 1-2-3 Cleaners is switched on by On/Off valve AV-4215, on a line from Loop 1 Continuous Clear Filtrates pump 05PPC07. On/Off valve AV-4215 is forced closed if 05PPC07 is not running.

The Stages 1-2-3 Cleaners canisters Sealing chambers are fed through On/Off valve AV-4013. 402-HS-6264 is switched on when 3rd stage pump 04PPC07 starts and remains open.Water for canisters Sealing chambers are provided either from Fresh Water (through manual valve MV-4257) or from Loop 3 dilution water (through manual valve MV-4259).

Note: In case the reject dilutions are not set properly, blockage may occur in the reject lines going from the Canisters back to the Cleaner feed pumps. In this case, this blockage occurs typically above the manual valve used to adjust counter-pressure on reject line. In the first weeks of operation, or after having changed the valves settings, the reject lines of the Cleaner system will usefully be routinely checked by operator: a blockage will be detected by 1) an increase in reject compartment pressure, and 2) cold pipe line. In case of an onset of block-age, opening and closing the manual valve easily remove the blockage.




Cleaners stage 1: 2 x Canisters size H7 with 108 Cleaners ELP136 in each.Inlet flow 2160 m3/h at consistency 1% (i.e. 550 BDMT/

24h)

Cleaners stage 2: 1 Canister size H6 with 72 Cleaners ELP136Inlet flow 680 m3/h at consistency 1% (i.e. 155 BDMT/

24h)

Cleaners stage 3: 1 Canister size H4 with 24 Cleaners ELP136Inlet flow 230 m3/h at consistency 0,8% (i.e. 40 BDMT/

24h)

Cleaners stage 4: 1 Bank of 3 Cleaners ELP440 BCInlet flow 80 m3/h at consistency 0.5% (i.e. 10 BDMT/24h)




LICS 4005Desaeration chest 04CPA01 level con-troller

5% 15% 85% 95% 0-150 m³

PIC 4010 Cleaners accepts pressure control 0–4 Bars

PIS 4030St. 1 Cleaners 04CLR04A inlet pressure indicator

1 4 0–5 Bars

PIS 4020St. 1 Cleaners 04CLR04A Accept pres-sure indicator

0,5 3 0–5 Bars

PDIS 4035St. 1 Cleaners 04CLR04A differential pressure 1 indicator

(Difference between inlet & accept)0,8 2

0–3 Bars

Software only

PIS 4045St. 1 Cleaners 04CLR04A Reject pres-sure indicator

0,6 0–5 Bars

PDIS 4050St. 1 Cleaners 04CLR04A differential pressure 2 indicator

(Difference between inlet & reject)

0–3 Bars

Software only

PIS 4080St. 1 Cleaners 04CLR04B inlet pressure indicator

1 4 0–5 Bars

PIS 4070St. 1 Cleaners 04CLR04B Accept pres-sure indicator

0,5 3 0–5 Bars

PDIS 4085St. 1 Cleaners 04CLR04B differential pressure 1 indicator


0–3 Bars

Software only



PIS 4095St. 1 Cleaners 04CLR04B Reject pres-sure indicator

0,6 0–5 Bars

…/…





PDIS 4100St. 1 Cleaners 04CLR04B differential pressure 2 indicator


0–3 Bars

Software only

PIS 4130St. 2 Cleaners 04CLR06 inlet pressure indicator

1 4 0–5 Bars

PIS 4120St. 2 Cleaners 04CLR06 Accept pressure indicator

0,5 3 0–5 Bars

PDIS 4135St. 2 Cleaners 04CLR06 differential pres-sure 1 indicator


0–3 Bars

Software only

PIS 4145St. 2 Cleaners 04CLR06 Reject pressure indicator

0,6 0–5 Bars



0–3 Bars

Software only


1 4 0–5 Bars


0,5 3 0–5 Bars



0–3 Bars

Software only

PIS 4195St. 3 Cleaners 04CLR08 Reject pressure indicator

0,6 0–5 Bars



0–3 Bars

Software only


1 4 0–5 Bars


0,5 3 0–5 Bars

PDIS 4255St. 4 Cleaners 04CLR10 differential pres-sure indicator


0–3 Bars

Software only




89- DESAERATION CHEST LEVEL LICS4005 TO AGITATOR 04AG02

If Desaeration chest level LICS4005 is Low-LowThen Stop Agitator 04AG02

If Desaeration chest level LICS4005 is LowThen Inhibit Start Agitator 04AG02

If Desaeration chest level LICS4005 is not LowAnd Agitator 04AG02 in DCS Auto mode


90- INTERLOCKS LOOP 1 PERIODIC WATER PUMP 05PPC08 to DESAERATION CHEST WATER VALVES

If Loop 1 Periodic Water pump 05PPC08 is not running

Then Desaeration Chest level controller LICS4005 is disabled With control valve LCV-4005 forced closedAnd filling On/Off valve AV-4006 forced closed

91- INTERLOCKS TO CLEANERS STAGE 1 FEED PUMP 04PPC03

If Disc Filter 05FDQ01 is not runningOr Cleaners stage 2 pump 04PPC05 is stoppedOr Desaeration chest 04CPA01 level controller LICS4005 is Low-LowOr St. 1 Cleaners 04CLR04A inlet Pressure PIS4030 is on alarm High-High

(>4,0 Bar g) for 15 s Or St. 1 Cleaners 04CLR04B inlet Pressure PIS4080 is on alarm High-High

(>4,0 Bar g) for 15 s

Then Stage 1 Cleaners feed pump 04PPC03 is stopped.

If Desaeration chest 04CPA01 level controller LICS4005 is LowOr Loop 1 Disc Filter 05FDQ01 is NOT Ready

Then Inhibit Start of Stage 1 Cleaners feed pump 04PPC03.



92- INTERLOCKS FROM STAGE 1 CLEANERS FEED PUMP 04PPC03

If Stage 1 Cleaners Feed Pump 04PPC03 is not running

Then On/Off slave valve AV-4110 is forced closedAnd Accept pressure controller PIC4010 is disabled with control valves PCV-

4010A and PCV-4010B forced closed.

If Stage 1 Cleaners Feed Pump 04PPC03 is running

Then With On-Delay T=5s, Open slave valve AV-4110 (air exhaust limit to open 15s)


If Cleaners stage 3 pump 04PPC07 is stoppedOr Water tank 05CE03 level controller LIS5055 is LowOr St. 2 Cleaners inlet Pressure PIS4130 alarm High-High (>3,0 Bar g) for

15 s

Then Stage 2 Cleaners Feed Pump 04PPC05 is stopped.

94- INTERLOCKS FROM STAGE 2 PUMP 04PPC05 To SLAVE VALVE

If Stage 2 Cleaners Feed Pump 04PPC05 is not runningThen On/Off slave valve AV-4160 is forced closed

If Stage 2 Cleaners Feed Pump 04PPC05 is runningThen With On-Delay T=5s, Open slave valve AV-4160 (air exhaust limit to

open 15s)


If Cleaners stage 4 pump 04PPC09 is stoppedOr Water tank 05CE03 level controller LIS5055 is LowOr St. 3 Cleaners inlet Pressure PIS4180 alarm High-High (>3,0 Bar g) for

15 s

Then Stage 3 Cleaners feed pump 04PPC07 is stopped.



96- STAGE 3 CLEANERS FEED PUMP 04PPC07 TO SLAVE VALVE AV-4210


If Stage 3 Cleaners Feed Pump 04PPC07 is runningThen With on delay T=5s AV-4210 in Auto is opened (air exhaust limit to open

15s)


If Water tank 05CE03 level controller LIS5055 is LowOr St. 4 Cleaners inlet Pressure PIS4250 alarm High-High (>3,0 Bar g) for

15 s

Then Stage 4 Cleaners Feed Pump 04PPC09 is stopped.

98- STAGE 4 CLEANERS FEED PUMP 04PPC09 TO SLAVE VALVE AV-4220


If Stage 4 Cleaners Feed Pump 04PPC09 is runningThen With on delay T=5s AV-4220 in Auto is opened (air exhaust limit to open

15s)

99- INTERLOCKS FROM LOOP 1 CONTINUOUS WATER PUMP 05PPC07

If Loop 1 Continuous Water pump 05PPC07 is not runningThen St. 1-2-3 reject dilution On/Off valve AV-4215 is forced closed.

If Loop 1 Continuous Water pump 05PPC07 is not runningThen Inhibit start of stage 3 Cleaners Feed Pump 04PPC07.

100- FRESH WATER AVAILABLE INTERLOCKS

If Fresh Water is not available (Process value to be identified)

Then St. 4 reject dilution On/Off valve AV-4225 is forced closedAnd Inhibit start of stage 4 Cleaners Feed Pump 04PPC09And St. 1-2-3 canisters sealing chambers filling main On/Off valve AV-4013

is forced closed (if fed by Fresh Water through manual valve MV-4527).



101- LOOP 3 WATER AVAILABLE TO ON/OFF VALVE AV-4013

If Loop 3 water dilution pump 13PPC09 is not running

Then St. 1-2-3 canisters sealing chambers filling main On/Off valve AV-4013 is forced closed (if fed by Loop 3 Water through manual valve MV-4529).

102- (RESERVE)

103- (RESERVE)

ALARMS

104- SEALING WATER

If Cleaning area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


105- DILUTION WATER TANK 05CE03

If Water tank 05CE03 level controller LIS5055 is Low


106- COMPRESSED AIR

If Cleaning area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


107- (RESERVE)



1.29 OPERATION

1.29.1 Start-Up

Starting the Fine-Cleaning system should be done after having started Loop 1 Disc Filter 05FDQ01.Feeding forward from the Stage 1 Cleaners will remain forbidden until Disc Filter is running, but there is no interlock preventing to start the 2-3-4 stage Cleaners independently from the rest of the line, provided filtrates are available in Loop 1 Filtrate Tank.

The following sequences are an explanation going with function charts describing all Cleaning area operation. Programming must be done in priority with Func-tion charts (supplied separately by Kadant).



alarm Low.- Compressed air system is under pressure (pressure PIA19202 not on Alarm

Low).- Fresh water is available.- Level control LIS5055 of water tank 05CE03 must be at least 85%.- Desaeration chest 04CPA01 level LICS4005 is not on alarm Low (this chest

to be filled with water on first start-up).- Disc Filter 05FDQ01 is ready to start (READY status)

If not already running, start Filtrate pumps: Loop 1 Periodic white water pump 05PPC08. Loop 1 Continuous white water pump 05PPC07. Loop 3 water dilution pump 13PPC09 if St. 1-2-3 canisters sealing

chambers fed by Loop 3 Water through manual valve MV-4529.

Start Stage 4 Cleaners feed pump 04PPC09When running status obtained, wait 10s and proceed.




Note 1: On/Off valves on water circuits are to be opened as described in associ-ated Function Charts.

Note 2: All regulations and other On/Off valves will be enabled and set to Auto-matic position through interlocks.



1.29.1.2 Production

Fine screening area starts in production with the flotation bloc (Once the stock is bled downstream of the constant level box 02CP20 via control valve FCV-3020).

Accepted stock from Pre-Flotation area feeds Desaeration chest 04CPA01 through constant level box 03CP07.

Stock feed can proceed to Cleaners when the Loop 1 Disc Filter is Ready.

NB: The process block can run few minutes in water mode if the flotation loop is running into water mode.

1.29.2 OperationTo be monitored during the operation of the installation:

Inlet, accept and differential pressures of cleaner. Consistencies. The absence of fibers rejected in the cleaner rejects.

1.29.3 Shutdown


The process bloc stops in production with the Flotation, by closing of the valve FCV-3020 at the outlet of the constant level box 02CP20.Over a few minutes, the circuit is left running with water to dilute the stock in the flotation and Cleaning loops.

NB: The process block can run few minutes in water mode if the flotation loop is running into water mode.


Once the units are clean, the Fine cleaning loop is stopped:

Stop the stage 1 cleaners feed pump 04PPC03.Wait T=10s then proceed,



Stop the stage 4 cleaners feed pump 04PPC09.

Note On/Off valves on water circuits are to be closed as described in associated Function Charts.



PROCESS DESCRIPTION


PRINTING - WRITING

LOOP 1 DISC FILTER& WATER DISTRIBUTION

LOOP 1 DISC FILTER & WATER DISTRIBUTIONPage 114/264


8 LOOP 1 DISC FILTER & WATER DISTRIBUTION

1.30 DESCRIPTION


Disc Filter .............................................................................05FDQ01

Clear filtrate tank ...............................................................................05CE03

Cloudy filtrate tank ...............................................................................05CE02

Pulper water tank ...............................................................................05CE04

Pulper water transfer pump .....................................................................................05PPC05

Disc Filters showers feed pump ..............................................................................05PPC06

Loop 1 continuous water dilution pump ...................................................................05PPC07

Loop 1 periodic water dilution pump ........................................................................05PPC08

1.30.2 Disc Filter basics

1.30.2.1 Disc Filter Description

Filter rotorThe filter is built around a horizontal shaft with internal axial filtrate channels lead-ing to one end of the shaft (or both ends if the filtrate quantities are very large).A number of filter discs are mounted on the shaft, each disc consisting of 20 sec-tors, connected to corresponding flow channels in the shaft.Approx. 70% of the disc area is submerged in a vat, containing the suspension to be filtered.The open end of the shaft is connected to a filtrate valve, which opens and closes the flow channels to a vacuum created by means of a barometric leg of the clear filtrate pipe. The disc filter drive set includes a shaft-mounted bevel planetary gearbox, which accepts a flanged motor into a hollow input. A torque arm is provided to restrain the shaft mounted gearbox for transmitting the drive.

Filter segmentsThe rotor consists of a set of circular discs mounted on a centre shaft in welded and bolted construction.Each disc accommodates 20 sectors. The sectors are fabricated in stainless steel construction and covered with a 420-micron polyester filter cloth. The filter cloth is replaceable.The special design of the sectors enables forming a strong basket design, as well as minimized inside volume for reaching an optimum filtrate discharge. The fil-



trate drained through the discs is led to the outer filtrate channels welded on the periphery of the centre shaft. The filtrate channels are sloped towards the end and carry the filtered water to the filtrate valve and from there through the outlet pipes.

Filter vatThe vat is in welded stainless steel construction and provided with outside rein-forcements at both ends.The bottom of the vat is provided with drainage connection. A level transmitter in-stalled on the vat enables automatic control of the rotor speed based on the level inside the vat and the inlet flow to the filter.

Filtrate Valve Between the rotating "spider" on the centre shaft and the fixed filtrate valve a set of renewable wear plates in UHMWPE are installed.The wear plates are bolted to the filtrate valve and kept pressed against the face of the rotating centre shaft by three adequately sized pressure springs supported by mounting bolts.A sealing arrangement around the wear plate is provided for preventing leakage between the shaft and the valve.

The filtrate valve at the end is equipped with two filtrate outlets: one for cloudy and other for clear filtrate. Proportion of the clear filtrate could be adjusted by varying the position of a special filtrate split device inside the filtrate valve. An ad-equately sized manhole with lid is provided on the filtrate valve for accessing this adjustment device.

Inlet feed boxThe inlet feed box is welded on the vat side and equipped with inspection/service covers.The feed box is provided inside with floating louvers and weirs, giving a uniform distribution of incoming stock along the filter length. The louvers float along with the liquid level in the vat thereby preventing entrapment of air into the feed liquid due to turbulence.

Filter hoodThe disc filter is provided with a welded stainless steel construction hood with ad-equate number of inspection covers on either side as well as on top side for ob-servation of performance as well as for ease of maintenance.The covers along the sides are open able.The shower pipe assemblies are mounted and supported inside the hood.The removable side covers also provide access for maintenance of the showers and nozzles.

ShowersOscillating showerThis consists of a main distributing header with branch pipes, oscillating between the discs.Each branch pipe is provided with four water jets for cleaning either side of the disc, efficiently washing the filter segments on the discs.Special “C” nozzles are provided for discharging the water jets. Each nozzle can deliver a flow of 16 LPM at 7 bar (g) pressure. The “C” nozzles enable any clog-ging or choking to be cleared easily just by a twist of the handle.



Dismantling of the water jets is not necessary.Oscillating drive arrangement includes a gear motor and a crank arrangement. Clear filtrate from the filter is used as washing water.

Knock-off showerThis consists of a main distributing header with branch pipes between the discs.Each branch pipe is provided with one water jet on either side of the disc, effi-ciently discharging the fiber mat formed on the disc surface. Same “C” nozzles are provided for this also as detailed above.Clear filtrate from the filter is used as knock-off water.

Sluicing showerThis consists of a main distributing header with branch pipes between the discs. Each branch pipe is provided with one water jet, to aid in the proper flow of the discharged fiber mat through the collecting boxes. Same “C” nozzles are provided for this also as detailed above.Clear filtrate from the filter is used as knock-off water.

Stock Collecting BoxesThe stock collecting boxes are in welded stainless steel construction and located inside the vat and uniformly arranged between the adjacent discs.These collecting boxes are so strategically placed to receive the knocked-off fiber mat from the discs and convey it to the discharge screw mounted below the trough.

Discharge ScrewThe recovered stock falls into a discharge screw mounted at the bottom of the trough.The discharge screw is built around a hollow stainless steel pipe and provided with end shafts running over roller bearings.The drive set consists of a gear box with hollow output and a flanged motor dir-ectly mounted.The discharge screw flight is cut and folded at intervals and also provided with paddles at the discharge end to break-up the fiber mat and feed the stock uni-formly through the outlet nozzle.



1.30.2.2 Disc Filter operation principle

The fiber suspension enters the filter via the inlet feed box A and is uniformly dis-tributed across the entire length of the trough.The inlet box has a float arrangement B that moves up and down with the level of the stock in the trough thereby eliminating air entrapment in the liquid.

As the centre shaft C and discs D rotate, initial filtration takes place by gravity and the pulp mat starts to form on the disc sectors, ensuring optimal dewatering characteristics.At this stage, the water removal takes place by physical filtration through the filter bags on the disc sectors. The filtrate is drained via the open grid segments to the corresponding outer channels E that forms the cloudy filtrate, which gets extrac-ted through the nozzle F on the filtrate vale.

As the discs rotate further, clear filtrate gets extracted through the portion of the spider coming under vacuum due to the barometric drop leg and this water also flows through the flow channels to the filtrate valve G and out through another nozzle H.Clear filtrate is formed under negative pressure when the filtration takes place through the fiber mat already formed on the discs. When the segments emerge from the suspension they are drained and the pulp mat is dewatered under neg-ative pressure.

The fiber mat is knocked-off at the top by means of knock-off nozzles I and falls through the collecting boxes J directly into the discharge screw trough K.

The filter cloths are cleaned by oscillating nozzles L before the filtration proced-ure starts over again.

The shower headers are supported inside a hood N, which also serves to cover the whole disc filter.

The cleaning shower nozzles are mounted on the oscillating shower header M, which is driven by a geared motor O through an oscillating mechanism. The disc filter rotor is rotated by a main drive consisting of a planetary gear box P and electric motor run through a variable frequency drive.

The repulper at the bottom of the trough is driven by a gearbox / motor Q directly mounted on repulper shaft.

The entire disc filter equipment is provided with an MS fabricated base frame R, which supports the equipment on a civil foundation.

The normal barometric leg recommended for a good installation would be 7M from the top of the water level in seal pit to the centreline of the filtrate valve.For an optimum filtration / thickening efficiency of the disc filter, the barometric leg is of paramount importance, as this decides the amount of vacuum available for the dewatering process.The vacuum in the clear filtrate leg would be around 350 to 400 mm Hg for good dewatering performance.



The disc filter rotates at a maximum speed of 2 RPM.The speed could vary between 0.5 to 2 RPM that would be automatically con-trolled based on the trough liquid level by the variable frequency drive on the main motor. The customer’s DCS or PLC system should be programmed to achieve the above control loop based on level transmitter readings.

Disc Filter Overview




1.30.3.1 Loop 1 Disc Filter

The Loop 1 Disc Filter 05FDQ01 thickens the pulp flow accepted from the Fine-Cleaning system, from 1% to 10-12%.

Brightness on feed to Loop 1 Disc Filter is measured by transmitter AIR5015 and displayed/recorded.

Pulp pH on feed to Loop 1 Disc Filter is measured by transmitter AIR5005 and displayed/recorded.

The Disc Filter main drive speed controller SIC5025 maintains the level LIC5020 in Disc Filter 05FDQ01 vat.

This is the only control on the Disc Filter:- When the hydraulic through-put fed to the disc filter increases, leading to in-

crease the pulp level in the vat, the Disc filter drive speed increases.- When the hydraulic through-put fed to the disc filter decreases, leading to in-

crease the pulp level in the vat, the Disc filter drive speed decreases.

The filtrate supply to the Disc Filter showers, from its own Clear filtrates for both oscillating showers and Knock-off showers, is switched on by actuating On/Off valve AV-5035.Pressure indicator PI5040 on filtrates supply line to Knock-off shower ensures the adequate pressure is available.The respective shower flows are adjusted by setting of manual valves.

Transmitter PI5050 measures vacuum available for Disc Filter operating in Clear filtrate barometric leg.

A speed switch SS5030 supervises the Repulping Screw 05FDQ01b rotation.

The accepted 10-12% stock falls in stand pipe of MC pump 05PMC10 feeding-Screw-press & Dispersing 1.

The Shower pump 05PPC06 ensures the cleaning & unplugging of the Disc Filter sectors wire, using the Disc Filter's own clear filtrates.

1.30.3.2 Loop 1 water distribution

The Loop 1 Filtrate distribution system ensures the filtrate requirements for Loop 1 are covered.

Clear Filtrate tank 05CE03This tank receives:

Clear filtrate extracted from Disc Filter 05FDQ01. Complement water from loop 2 water pump 10PPC09 (through control

valve LCV-5010). Tank filling water also from loop 2 water pump 10PPC09 (through On/

Off valve AV-5051).



The level is measured by LIS5055.

Tank 05CE03 is used to feed: Loop 1 Continuous white water pump 05PPC07 Loop 1 Periodic white water pump 05PPC08 Disc Filter showers pump 05PPC06 Cleaners feed pumps 04PPC05 (Stage 2), 04PPC07 (Stage 3) and

04PPC09 (Stage 4).

A continuous overflow to Cloudy water tank 05CE02 allows a constant level of water and then avoids pressure variations at connected pump suctions, and transfers complement to downstream water tanks.

Cloudy Filtrate tank 05CE02This tank receives:

Cloudy filtrate extracted from Disc Filter 05FDQ01. Loop 1 Screw-press 06PVS01 filtrates. Overflow from Clear Water tank 05CE03.

The level is measured by LIS5045.

Tank 05CE02 is used for dilution of Pre-flotation feed pump 03PPC01.

Cloudy filtrates in excess overflow by gravity from to Pulper water tank 05CE04 and allow complement to downstream water tanks.

Pulper water tank 05CE04Pump 05PPC05 connected to this tank transfers Loop 1 filtrate to Buffer tank 05CE11 for:

Dilution of Pulping area. Storage of excess filtrate during transitory phases (for example shut-

down of Loop 1 when filtrate generated by thickening is no more con-sumed for Loop 1 process dilutions)

Level of tank 05CE04 is controlled by loop LIC5010 acting on control valve LCV-5010 on make-up water from Loop 2 Periodic Filtrates pump 10PPC09, falling in Clear Filtrate tank 05CE03 and overflowing successively to tank 05CE03 and fi-nally to tank 05CE04.This configuration enables Low levels LIS5045 and LIS5055 to call also for water complement in case of water deficit in corresponding water tank.




Disc Filter: Ø 5200mmInlet flow 1850 m3/h at consistency 0,9% (i.e. 410

BDMT/24h)




AIR 5005 PH indication of Disc Filter feed pulp 5 to 11

AIR 5015Brightness indication of Disc Filter feed pulp

LIC 5020 Disc Filter 05FDQ01 vat level control 50% 95% 100% 0-100%

SIC 5025Disc Filter 05FDQ01 main drive motor speed control

0-100%

SS 5027Disc Filter 05FDQ01 main drive zero speed alarm

* Digital alarm

SS 5030 Disc Filter Repulper zero speed alarm * Digital alarm

PI 5040Disc Filter 05FDQ01 shower header pipe pressure indication

3,2 7 0–8 Kg/cm2g

PI 5050Disc Filter 05FDQ01 Clear Filtrate va-cuum indication

200 275- 600 to 0 mm HG

LIC 5010 Pulper water tank 05CE04 level control 10% 15% 80% 90% 0-60 m3

LIS 5045Cloudy filtrate tank 05CE02 level con-trol

10% 25% 0-60 m³

LIS 5055 Clear filtrate tank 05CE03 level control 10% 25% 0-60 m³




1.33.1 Loop 1 Disc Filter 05FDQ01

108- MC PUMP 05PMC10 TO DISC FILTER 05FDQ01

If MC pump drive 05PMC10 is stopped

Then Disc Filter Repulping Screw is stopped.

109- INTERLOCKS TO DISC FILTER REPULPER SCREW 05FDQ01b

If Disc Filter Repulping screw 05FDQ01b is running with start-up override T=5s

And Speed switch SS5030 is alarm (zero)

Then Disc Filter Repulping screw 05FDQ01b is stopped and alarm generated.

110- DISC FILTER OUTLET SCREW MOTOR TO SHOWERS WATER PUMP

If Motor (M6043) of Disc Filter discharge screw is running

Then Showers water pump 05PPC06 is allowed to start

111- SHOWERS PUMP 05PPC06 TO SHOWER OSCILLATING DEVICE MOTOR

If Showers water pump 05PPC06 is not running or tripped

Then Filter oscillating shower device motor (M6044) is forced to stop

112- INTERLOCKS TO DISC FILTER MAIN MOTOR

If Filter oscillating shower device (M6044) is not running or tripped

Then Disc Filter main motor (M6042) is forced to stop

If Repulper drive motor (M6043) is not running or tripped


If Main Motor (M6042) of Disc Filter is runningAND Filter zero speed switch “SS-5027” is on alarm Low

Then Stop main motor (M6042) of Disc Filter



113- INTERLOCKS FROM DISC FILTER 05FDQ01

If Disc Filter Main Motor “M6042” is tripped during running

Then Filter vat level controller “LICA-5020” is DISABLEDAND Stock feeding pump “04PPC03” to cleaners is forced to STOP

114- (RESERVE)

1.33.2 Loop 1 water distribution

115- INTERLOCKS TO PULPER WATER TRANSFER PUMP 05PPC05

If Pulper water tank 05CE04 level LIC5010 is Low-LowOr Buffer tank 05CE11 level LIS5000 is High

Then Pulper water transfer pump 05PPC05 is stopped.

If Pulper water tank 05CE04 level LIC5010 is LowThen Inhibit start of Pulper water transfer pump 05PPC05

116- TRANSFER PUMP 05PPC05 TO SLAVE VALVE AV-5014

If Pulper water transfer pump 05PPC05 is not runningThen On/Off slave valve AV-5014 is forced closed

If Pulper water transfer pump 05PPC05 is runningThen With on delay T=5s, On/Off slave valve AV-5014 in Auto opens

117- INTERLOCKS TO SHOWERS WATER PUMP 05PPC06

If Clear filtrate tank 05CE03 level LIS5055 is Low-LowOr Disc Filter 05FDQ01 main motor is not running

Then Disc Filter shower pump 05PPC06 is stopped.

If Clear filtrate tank 05CE03 level LIS5055 is LowThen Inhibit start of Disc Filter shower pump 05PPC06



118- SHOWERS WATER PUMP 05PPC06 TO DELIVERY VALVE AV-5035

If Disc Filter shower pump 05PPC06 is not runningThen On/Off slave valve AV-5035 is forced closed

If Disc Filter shower pump 05PPC06 is runningThen With on delay T=5s, On/Off slave valve AV-5035 in Auto opens (air ex-


119- INTERLOCKS TO LOOP 1 CONTINUOUS WATER PUMP 05PPC07

If Clear filtrate tank 05CE03 level LIS5055 is Low-LowThen Continuous water pump 05PPC07 is stopped.

If Clear filtrate tank 05CE03 level LIS5055 is LowThen Inhibit start of Continuous water pump 05PPC07

120- LOOP 1 CONTINUOUS WATER PUMP 05PPC07 TO SLAVE VALVE AV-5090

If Continuous water pump 05PPC07 is not runningThen On/Off slave valve AV-5090 is forced closed

If Continuous water pump 05PPC07 is runningThen With on delay T=5s, On/Off slave valve AV-5090 in Auto opens (air ex-


121- INTERLOCKS TO LOOP 1 PERIODIC WATER PUMP 05PPC08

If Clear filtrate tank 05CE03 level LIS5055 is Low-LowThen Periodic water pump 05PPC08 is stopped.

If Clear filtrate tank 05CE03 level LIS5055 is LowThen Inhibit start of Periodic water pump 05PPC08

122- LOOP 1 PERIODIC WATER PUMP 05PPC08 TO SLAVE VALVE AV-5085

If Periodic water pump 05PPC08 is not runningThen On/Off slave valve AV-5085 is forced closed

If Periodic water pump 05PPC08 is runningThen With on delay T=5s, On/Off slave valve AV-5085 in Auto opens (air ex-




123- (RESERVE)

ALARMS

124- SEALING WATER

If Loop 1 Disc Filter & water distribution area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


125- COMPRESSED AIR

If Loop 1 Disc Filter & water distribution area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


126- (RESERVE)



1.34 OPERATION

1.34.1 Start-up

Loop 1 water distribution is the first area to start in Loop 1, in order to store ne-cessary water for all equipment start-up and dilution.



Low).- Loop 2 filtrate tanks levels LIC9050 and LIS9055 are not Low

1.34.1.1 Water tanks filling

If water tanks are empty (for example on first start-up):

Open On/Off water valve AV-5051 for filling of Clear filtrate tank 05CE03 with Loop 2 filtrates provided by pump 10PPC09.

Other tanks 05CE02 and 05CE04 in cascade are filled with successive overflows.

When allowed through interlocks, start pump 05PPC05 to fill Buffer tank 05CE11 up to sufficient level to launch pulping sequences.

As soon as water tank levels are up to Low level, connected water pumps can start if required by the sub-systems or in manual by operator.

1.34.1.2 Disc Filter 05FDQ01 start

Basic conditions:- Clear Filtrate tank 05CE03 level LIS5055 is not Low.- MC Pump 05PMC10 stand pipe level LICS5065 is not High

For start-up of sequence, the clear filtrate seal chamber should be filled with either clear filtrate or fresh water up to the maximum level of this chamber so that overflow occurs into the clear filtrate tank.

Start Loop 1 Disc Filter Repulping screw 05FDQ01b.

Start Disc Filter Shower Pump 05PPC06 and open its delivery valve AV-5035.

Start Oscillating shower drive 05FDQ01c.

Start Loop 1 Disc Filter Main Drive 05FDQ01.

When running status obtained for both, set Disc Filter status to READY.



1.34.1.3 Production

The process bloc starts in production with the flotation bloc and cleaning bloc (Once the stock is bled downstream of the constant level box 02CP20 via control valve FCV-3020).

Cleaners feed pump 04PPC03 is allowed to start with Disc Filter READY status.

When feed pump 04PPC03 is started:Put the Disc Filter trough level controller LIC5020 in AUTO Mode.

NB: The process block can run few minutes in water mode if the flotation loop and cleaning & fines screening loop are running into water mode.

1.34.2 Operation

The different steps run off automatically.

Monitoring of HP shower water pressure. Monitoring of consistencies (Water and stock). Monitoring of operating vacuum



1.34.3 Shutdown


The process bloc stops in production with the flotation bloc and the cleaning loop, by closing of the control valve FCV-3020 outlet of the constant level box 02CP20.

Loop 1 Disc Filter stops in production with stop of feed pump 04PPC03.

1.34.3.2 Disc Filter 05FDQ01 stop

Reset Disc Filter status to Not READY

Stop the disc filter main motor after time delay of 10 minutes to ensure that as much of fiber is recovered as possible from the liquid in the trough.

Stop Loop 1 Disc Filter Oscillating shower drive 05FDQ01c.

Stop Disc Filter Shower Pump 05PPC06 and close its delivery valve AV-5035.

Stop the stock repulper screw drive after time delay of 5 minutes, to ensure that stock does not remain in the screw trough during stoppage.

CAUTION!It would be preferable to operate the Disc Filter system for 5-10 minutes with just showers water for internal cleaning prior to any medium duration stoppage (up to 4 hours).

For stoppages exceeding 4 hours, it would be preferable to clean the internal sys-tem and have the trough drained fully. The contents of the trough should be drained very slowly and gradually to avoid physical damage to the internal com-ponents of the trough and rotor due to build-up of vacuum caused by excessively rapid draining (siphon effect). Use of wire cleaning showers to clean the filter fab-rics is recommended. The inside of the hood and the showers pipes should also be cleaned with water hose under pressure.

1.34.3.3 Loop 1 Water distribution

Filtrate pumps 05PPC05, 05PP07 & 05PPC08 are stopped when no more re-quired by any Loop 1 sub-systems.



PROCESS DESCRIPTION


PRINTING - WRITING

LOOP 1 THICKENING -KNEADING &

OXIDATIVE BLEACHING

LOOP 1 THICKENING – KNEADING – OXIDATIVE BLEACHINGPage 130/264


9 LOOP1 THICKENING, KNEADING AND OXYDATIVE BLEACHING AREA

1.35 DESCRIPTION


Stand Pipe ...............................................................................14CE02

MC pump ............................................................................05PMC10

Recirculation chest .............................................................................07CPA11

Recirculation chest agitator......................................................................................07AG12

Recirculation chest extraction pump........................................................................07PPC13

Screw press .............................................................................06PVS01

Kneader ................................................................................06TL02

Bleaching tower .............................................................................07CPA01

Bleaching tower vertical agitator .............................................................................07AG02

Bleaching tower rotating extraction mixer................................................................07AG03

Bleaching tower extraction pump.............................................................................07PPC07

1.35.2 MC Pump basics

The MC-Pump system consists of

- A stand pipe for Pump feeding with thick stock.

- The MC Pump itself, with a special pulp impeller that fluidises the pulp.

For more details, please refer to supplier documentation.

1.35.3 Screw Press basics

Screw press is composed of the following elements mounted on a base frame:- Press screw with conical-cylindrical shape and screw pitch reduced from inlet

to outlet of the press;- Press screen system, with Inlet screen (half cylinder), Draining section &

Compression section screen plates supported in half cylinder mantles;- Counter-pressure cone






1.35.4 Basics Kneader type TL

1.35.4.1 Kneader description

The pulp introduced into the Kneader is subjected to shear forces between stator & rotor, which conveys the pulp through the kneading zone, with a controlled counter-pressure maintained at the outlet of the Kneader.

The KADANT Kneader type TL is a single shaft Kneader, comprising the follow-ing elements:- Inlet & accept casing and support for inlet side/accept side bearing, base-

frame;- Cylindrical body, with connection for thick stock inlet, thick stock outlet, and

nozzles for steam injection. In Kneading zone, the mantled body supports the individual stator kneading fingers constituting the Kneader Stator.

- Rotating shaft, equipped with a conical screw in Feeding zone, and with ro-tating kneading fingers in Kneading zone, constituting the Kneader Rotor.

- Counter-pressure system, with pneumatically actuated flap on thick stock outlet (local pneumatic panel with pressure control, remote set-point).

The Kneader is equipped with a mechanical gear-drive & motor coupled to the Kneader drive shaft. The Kneader is operated at fixed speed.

The thick stock to be processed in fed by gravity into the Kneader stock inlet, and is carried forward by the screw in the Feeding zone into the kneading zone.

The kneading action takes place between the interpenetrating rows of fingers: ro-tating (rotor) and stationary (stator). As the pulp is forced forward through the area between the fingers, it is subjected to intense friction & shear, which determ-ine the kneading effect on the pulp.

The main process parameter to control the kneading effect is the specific en-ergy absorbed by the stock. The absorbed kW load is controlled by the pneu-matic counter-pressure applied on the stock outlet.

The counter-pressure system comprises of a pneumatically actuated flap moun-ted against the stock outlet. The pneumatic pressure applied to stock outlet flap is controlled from local pneumatic panel, with remote set point used to control ab-sorbed kW on the Kneader.

The energy absorbed by the stock in the Kneader leads to a significant temperat-ure increase. Steam injection into the Kneader, controlled by temperature meas-urement on the accepted stock, ensures an optimal accepted stock temperature optimal for bleaching as required.

1.35.4.2 Kneader Counter-pressure control & Pneumatic Panel

1.35.4.2.1Kneader Counter-pressure control & Pneumatic Panel



The Kneader local pneumatic panel comprises a pressure control of the Com-pressed air feed to the Kneader counter-pressure pneumatic actuator, with re-mote set point and On/Off release of air-pressure.

The counter-pressure system (abbreviated CP) is integrated into the process sys-tem using the following features:Counter-Pressure On/Off: the Kneader counter-pressure is put on or released at once by closing/opening of a solenoid valve.

Note: the local panel solenoid is Fail-open (1 to close).

Kneader Counter-Pressure set point: the set point to the pneumatic counter-pressure (= local controller JT-6030) is obtained from DCS controller JICS6030 (DCS output to local servo valve).

The process value input to JICS6030 controller is the Amp load feedback (ex-pressed in kW).

1.35.4.2.2Kneader Absorbed Power control: Counter-pressure

Kneader CP is to be set ON by operator. If Kneader CP is OFF, the Power con-troller is disabled with minimum counter-pressure set point to Kneader pneumatic panel, solenoid valve open to release pressure.

If Kneader High-High Amp load alarm, or in case of interlocks downstream to Kneader, reset Kneader CP to OFF.

When enabled by operator, the DCS Power controller JICS6030 controls the Counter-pressure local controller of the Kneader, at the Amp Load (or kW) set-point entered by operator:- If measured Amp load JICS6030 increases to above set-point, DCS controller

reduces counter-pressure;- If measured Amp load JICS6030 decreases to below set point, DCS control-

ler increases counter-pressure.

Note: the controlled value is absorbed kW - NOT specific absorbed kW. The set-point to the power controller will need to be adapted by operator taking into ac-count the through put of the line.

The Kneader absorbed Power is monitored by operator. Activating CP Absorbed Power control using Kneader CP ON remains an operator decision.

1.35.5 Basics Pollcon Tower

1.35.5.1 Pollcon tower description

The POLLCON High Consistency Bleaching Tower consists of the following ele-ments:

Top part:



- Support structure & bottom agitator drive, with torque transmitter (4-20 mA) integrated to gear-drive;

- Manhole & maintenance opening;- 4 openings for High Consistency Stock inlet;

Bottom Part:- Bottom agitator 07AG02 with 4 branches and dilution ramps, bottom support;- Connections to rotating dilution ramps and to central dilution box;- Annular dilution ring with valve & injectors to tower base;- Rotating extraction mixer 07AG03, with drive & dilution;- Level transmitter flange.

1.35.5.2 Pollcon tower operation

The Ox Bleaching Tower is fed with pulp at 30% from Kneader.

The pulp bleaching proceeds at high consistency, for the residence time of the pulp in the Bleaching Tower.

In the lower dilution zone of the Tower, the high consistency pulp is diluted to 4-5% through the following nozzles:- Dilution A: through annular dilution ring and injectors around the base of the

Tower;- Dilution B: through central dilution box- Dilution C: through rotating dilution ramps fixed on the agitator branches.- Dilution D: to Extraction Mixer zone.




Figure: POLLCON HC Bleaching Tower

Dilutions

- to Bottom Periphery

- to Central dilution Box- to Rotating Agitator

Dilutions

Dilution toExtraction Mixer

Stock Extracted

Agitator drive

A

B

C

D


1.35.6 Dispersion and Bleaching description

1.35.6.1 Transfer MC pump 05PMC10

Note: The following description for MC pump operation & associated regulations correspond with a Sulzer pump type.This paragraph is to be adapted and/or corrected in case of any other supplier.

Stock at 10-12% falls by gravity from the Loop 1 Disc Filter 05FDQ01 Repulping screw outlet into the MC Pump Stand-Pipe 14CE02.

Dilution water is injected to the stand-pipe at the top by HCV-5060 and to the base by LCV-5065. Both valves can be operated in manual or in Automatic.

The pump drive speed is controlled by SIC5068.

The level in the MC Pump Stand-Pipe is controlled by LICS5065 operating on MC pump motor speed controller SIC5068.

In addition, LICS5065 controls valves LCV-5065 & HCV-5060 dilution valves to Stand-pipe, opening the level dilution valves when the level rises.

In Manual mode, Top dilution valve HCV-5060 and bottom dilution valve LCV-5065 can be opened at any time.

In Auto mode, Top dilution valve HCV-5060 is opened at operator defined open-ing set-point + controlled value related to deviation of LICS5065 from set-point.Bottom dilution valve LCV-5065 is normally closed, and opens to operator set value when LICS5065 measure is greater than 30% above set-point and MC Pump is running.

The MC Pump 05PMC10 pumps the stock forward to downstream process.Consistency measurement via NI5110 has been added at the MC pump outlet just to be able to monitor the outlet consistency of the stock.

1.35.6.2 Recirculation chest 07CPA11

During transitory phase (like on start-up or during an eventual incident in down-stream process), a recirculation line from MC pump 05PMC10 outlet (through On/Off valve AV-6006 open and with On/Off valve AV-6010 closed) allows recir-culation of Loop 1 Accepted stock back to intermediate chest 07CPA11.

This pulp transferred to chest 07CPA01 is diluted in line with filtrates from pump 10PPC13 and through On/Off valve AV-6160 in order to decrease consistency from 10 to 4-5%.

Chest 07CPA011 is equipped with a horizontal agitator 07AG12 and level is con-trolled by LIC6007 acting on control valve LCV-6007 at extraction pump 07PPC13 outlet.

Extraction pump 07PPC13 transfers stock to Dump Chest 01CPA15.



Then when operator activates loop 1 accept stock recirculation to Dump chest, a sequence automatically:

Starts filtrate pump 10PPC13 Opens filtrate valve AV-6160 Opens by-pass valve AV-6006 and closes opposite valve AV-6010 Sets in Auto mode level controller LIC6007 Enables start of agitator 07AG12 and extraction pump 07PPC13 (mo-

tors start depend also on interlocks).

Recirculation chest 07CPA11 can also by fed Loop 2 Disc Filter accepted stock through MC pump 14PMC03.

1.35.6.3 Screw Press 06PVS01

The Screw-Press 06PVS01 thickens the 10-12% pulp (from Loop 1 Disc Filter via MC pump 05PMC10) to 30-35% consistency required for Kneading.

Transmitter PIS6005 measures screw-Press 06PVS01 feed pressure and a by-pass line (through On/Off valve AV-6150 with opposite On/Off valve AV-6015 closed) can send pulp directly to downstream bleaching tower 07CPA01.

Screw Press torque is controlled by JICS6020.

Screw press is equipped with a variable speed motor controlled by SIC6021.

These operating parameters (torque set-point/ operating speed range/ counter-pressure) of the screw press need to be adjusted on start-up to achieve adequate outlet consistency.

The consistency of thick stock at the outlet of the Screw Press results of the Torque JICS6020 and counter-pressure applied to the press, taking into account the type of pulp, the throughput, the inlet consistency.

Screw press speed control & Torque controller:

Inputs:Process value: Taken from the frequency converter and scaled to Nm.Set point: Operator controlled parameter.SP Ramp: 5 Nm per second.Auto/Manual: Default “Auto”. PV filter: 4s. Filter to flatten the process value signal.

To be applied either in frequency converter or in control system.Maximum output: This is to be set at 100%. Minimum output: To be set at 0%. Maximum SP: 50%. Minimum SP: 0%. HHAL: 70%.HAL: 60%.



Output:Output from controller forwarded frequency converter speed reference input.

Function:Process value < Set point makes output decrease.Process value > Set point makes output increase.

Refer to Screw Press supplier documentation for further operating description.

The filtrates extracted from the Screw press flow by gravity to Cloudy Filtrate Tank 05CE02.

The 30-35% consistency stock accepted from the Screw press feeds directly Kneader 06TL02.

1.35.6.4 Kneader 06TL02

Pulp falls directly from Screw Press 06PVS01 to Kneader 06TL02.

Necessary chemicals for oxidative bleaching are also introduced into the Kneader infeed hopper.Notes:

Chemicals flow should be proportional to line production. The supply of chemicals MUST be interlocked (hard) to the operation

of the Kneader and downstream equipment, and to the presence of stock in the Kneader (indicated by Kneader CP-Status ON).

The pulp introduced into the Kneader 06TL02 is subjected to shear forces between stator & rotor, which conveys the pulp through the kneading zone, with a controlled counter-pressure maintained at the outlet of the Kneader.

Kneader 06TL02 rotor is driven in rotation with a gearbox equipped with security alarms FSAL6135 and TSAH6050 (Gearbox temperature alarm).

Torque controller JICS6030 receives as process value input the Amp load % measured by the MCC and copied to DCS, and controls the set-point to local pneumatic panel counter-pressure local controller to Kneader counter pressure.

Operator sets the set-point to JICS6030; there is no remote set-point for specific energy control provided for at this stage.

Pulp into Kneader is heated with direct steam injection.The steam control valve TCV-6025 is controlled by the temperature loop TIC6025 measured on the thick stock accepted from the Kneader (TT on Kneader) in order to obtain a required bleaching temperature T= 80-95°C at outlet of Kneader (de-pends on operating conditions).



The thick stock accepted from Kneader falls by gravity into Bleaching Tower 07CPA01.



1.35.6.5 Pollcon Tower 07CPA01

The thick stock fall from Kneader into Bleaching tower 07CPA01 at consistency 30-35%.

The pulp bleaching proceeds at high consistency. Tower volume has been sized adequately to the required residence time of the pulp.

Bleaching tower 07CPA01 level is measured by LIS6070.

High Level LIS6070 is one of the main levels on the line, to be monitored by op-erator to control the production & stability on loop 1 by acting on Loop 1 produc-tion set-point (through command FIC3020 regulating stock feed to Pre-Flotation area).

The Ox Bleaching tower must have a minimum level of filtrates or stock prior to feeding thick stock - to prevent block agitator or extracting system. This requires pre-filling on filtrates prior to start the line. Operator does this filling manually from DCS.

Operation with stable Bleaching Tower level is recommended for stable Bleach-ing operation.

Bottom agitator 07AG02 is equipped with a torque alarm XS6080 to detect an eventual blockage of agitator.

The Bottom agitator 07AG02 torque JIC6085 controls the flow to Dilutions A-An-nular ring & B-Central box through control valve FCV-6085.

The dilution C flow is controlled by FIC6060 through control valve FCV-6060, with set-point in remote could be proportional to stock flow FI6115 extracted from Tower bottom to downstream fine screening.

In Extraction Mixer 07AG03, the Pulp is fluidised and further diluted by DILUTION D flow, controlled by measured consistency NRC6095 through control valve NCV-6095 in order to reach 4,5%.

All these dilution flows are fed with Loop 2 filtrates from pump 10PPC08.

Pump 07PPC07 extracts the stock from Bleaching tower to downstream Loop 2 process (i.e. Fine Screening feed chest 07CPA08).Flowmeter FI6115 measures this transfer flow.

Then Loop 2 production P2-5070 can be calculated from Flowmeter FI6115 and consistency controller NRC6095.




Screw press: Inlet 175 m3/h at consistency 10% (i.e. 400 BDMT/24h)Accept at consistency 30-35%

Kneader: TL3Installed Power: 1200 kWSpecific energy: 80-85 kW/BDT




MC Pump and Screw Press control loops to be checked with corresponding sup-plier.



HIC 5060Manual control valve of dilution water to top of Stand Pipe 14CE02

0-100%

LICS 5065MC Pump Stand Pipe 14CE02 level con-trol

5% 15% 85% 95% 0-100%

SIC 5068MC Pump 05PMC10 motor speed Con-trol

0-100%

NI 5110Consistency indication of Loop 1 thicken-ing - Bleaching

0 to 15%

LIC 6007Recirculation chest 07CPA11 level con-trol

5% 15% 85% 95% 0-30 m³

PIS 6005Screw Press 06PVS01 feed pressure in-dication

0–5 Bars

JICS 6020 Screw Press 06PVS01 torque control 0-700 m3/h

SIC 6021Screw Press 06PVS01 motor speed Control

0-100%

TIC 6025 Kneader 06TL02 temperature control 0-150°C

JICS 6030 Kneader 06TL02 Amp-load control 20% 70% 90% KW scale/MCCAnd unit 0-100%

FSAL 6135Kneader 06TL02 gear drive cooling water flow alarm

L Digital alarm

TSAH 6050Kneader 06TL02 gear drive temperature alarm

H Digital alarm

LIS 6070Oxidative bleaching tower 07CPA01 level control

5% 15% 85% 95%

JICS 6085Tower 07CPA01 Bottom agitator 07AG02 drive Torque controller

70% 90% 0-100%

XS 6080Tower 07CPA01 Bottom agitator 07AG02 drive Torque High switch

H Digital alarm

FIC 6060Oxidative bleaching tower 07CPA01 dilu-tion flow control (to rotating agitator)

0-200 m3/h

NRC 6095Oxidative bleaching tower 07CPA01 ex-tracted pulp consistency control

0–5%

FI 6115Oxidative bleaching tower 07CPA01 ex-tracted pulp flow indication

0-500 m3/h

P2 5070DIP line Loop 2 production indication

(Calculation with NT-6095 & FT-6115)Software only




MC Pump and Screw Press interlocks and alarms to be corrected and/or correc-ted with corresponding supplier.

1.38.1 Transfer MC pump 05PMC10

127- INTERLOCKS TO MC PUMP 05PMC10

If Bleaching Tower 07CPA01 level LIS6070 is alarm High-High for T=5sOr MC pump Stand Pipe level LICS5065 is Low-Low for 30sOr Screw Press 06PVS01 is not running when required (On/Off valves AV-

6010 & AV-6015 open, On/Off valves AV-6066 & AV-6150 closed)

Then MC Pump 05PMC10 is stopped

128- MC PUMP 05PMC10 INTERLOCKS TO CONTROLS & VALVES

If MC Pump 05PMC10 is not running

Then Level controller LICS5065 is disabledAnd Control valve HCV-5060 if in Auto is closedAnd Control valve LCV-5065 if in Auto is closedAnd Slave On/Off valve AV-5080 is forced closed

If MC Pump 05PMC10 is running (On delay T=20s)

Then Level controller LICS5065 is enabled to speed controller SIC5068

And Output to valve LCV-5065 is enabled(HCV-5060 output is enabled on motor start-order)

And Slave On/Off valve AV-5080 opens

129- LOOP 2 DILUTION WATER INTERLOCK TO MC PUMP WATER CONTROL VALVES

If Loop 2 periodic water pump 10PPC09 is not runningThen Control valves HCV-5060 and LCV-5065 are forced closed.

If Loop 2 periodic water pump 10PPC09 is not runningAnd MC Pump 05PMC10 is running

Then Alarm dilution to MC Pump is generated.



130- (RESERVE)

1.38.2 Recirculation chest 07CPA11

131- RECIRCULATION CHEST 07CPA11 LEVEL LIC6007 TO AGITATOR 07AG12

If Chest level LIC6007 is Low-LowThen Stop Agitator 07AG12

If Chest level LIC6007 is LowThen Inhibit Start Agitator 07AG12

If Chest level LIC6007 is not LowAnd Agitator 07AG12 in DCS Auto mode


132- INTERLOCKS TO EXTRACTION PUMP 07PPC13

If Recirculation chest level LIC6007 is Low-LowOr Dumping chest 01CPA15 level LIS1425 is High-High

Then Extraction pump 07PPC13 is stopped.

If Recirculation chest level LIC6007 is Low

Then Inhibit start Extraction pump 07PPC13

133- EXTRACTION PUMP 07PPC13 TO SLAVE VALVE LCV-6007

If Extraction pump 07PPC13 is not runningThen Control valve LCV-6007 is forced closed (Hard interlock)

If Extraction pump 07PPC13 is runningThen With on delay T=5s, control valve LCV-6007 in Auto opens

134- (RESERVE)



1.38.3 Screw Press 06PVS01

135- INTERLOCKS TO SCREW PRESS 06PVS01

If Kneader 06TL02 is not running (On-delay T=10s).Or OFF (computer) is activated (broken circuit).Or Emergency stop or service switch is activated (broken circuit).Or Slow speed limit switch is not activated (low speed = broken circuit).

Then Screw Press 06PVS01 is stopped.

136- INTERLOCKS TO SCREW PRESS 06PVS01 COUNTER PRESSURE CONE

If Screw Press 06PVS01 is not running.Or Open (computer) is selected (broken circuit).Or Pulp feed pump 05PMC10 is not running on delay T=30s.Or Screw Press speed Torque controller JICS6020 is on Alarm High

Then Counter pressure cone in Screw Press opens (solenoid valve ener-gized).

137- INTERLOCKS TO SCREW PRESS 06PVS01 SEALING WATER VALVE

If Screw Press 06PVS01 is not running.Then Sealing water On/Off valve closes

If Screw Press 06PVS01 is running.Then Sealing water On/Off valve opens

138- (RESERVE)

139- (RESERVE)

TO BE COMPLETED AND/OR CORRECTED IF NECESSARY

1.38.4 Kneader 06TL02

140- INTERLOCKS TO KNEADER 06TL02

If Oxidative bleaching tower 07CPA01 level is High-High for T=45s.Or Oxidative bleaching tower 07CPA01 level is Low-Low.

Then Kneader 06TL02 is stopped.



141- SCREW PRESS 06PVS01 & KNEADER 06TL02 RUNNING TO STEAM HEAT-ING TIC6025

If Kneader 06TL02 is not running (on-delay T=20s)Or Screw Press 06PVS01 is not running (on-delay T=20s)Or Temperature TIC6025 is alarm High-High (on-delay T=20s)

Then Temperature controller TIC6025 is disabled with valve TCV-6025 forced closed

And Steam isolation valve AV-6140 is forced off

Note: if TIC6025 is in Auto and the interlocking conditions are set to healthy, the controller is enabled after specified on-delays. In Manual, the controller remains at closed value.

142- KNEADER CP & KNEADER POWER CONTROL JICS6030

Operator action only sets Kneader CP_STATUS to ON, for example with push-button action on DCS synoptic.

If Operator resets Kneader CP_STATUS to OFFOr Screw-Press 06PVS01 is not runningOr Kneader Amp load JICS6030 is alarm High for T=2sOr Kneader 06TL02 is stoppedOr Oxidative bleaching tower 07CPA01 level is High

Then Kneader CP_Status is reset to OFF.

If Kneader CP_Status is OFF

Then Kneader torque controller JICS6030 is disabled With output to local CP ctrl forced to 0%

And Kneader counter-pressure On/Off solenoid valve is forced Off

Note: Kneader CP_Status ON is required to allow Chemical dosage to Kneader.

143- KNEADER INTERLOCK TO OXIDATIVE CHEMICAL DOSAGE

If Kneader CP_Status is to OFF (with on-delay T=30s)

Then Chemical supply to Kneader inlet is DISABLED (to Chemical dosage pumps).

The On-delay T=30s means that chemical supply to Kneader will remain forbid-den T=30s after the CP has been set ON.



144- (RESERVE)

1.38.5 0xidative bleaching tower 07CPA01

High level stops the Kneader 06TL02 after T=45s, while it stops the feed MC pump 05PMC10 immediately (T=5s), allowing to stop properly the Screw press-Kneading system.

The level setting for High-High alarm will leave room in Tower for T=45s produc-tion.

145- TORQUE CONTROL JIC6085, TORQUE HIGH SWITCH XS6080, FLOW CON-TROL FIC6060 & AGITATOR 07AG02

If Torque controller JIC6085 is High-HighOr Torque High Switch XS6080 is alarm

Then Stop Agitator 07AG02 (Hard interlock)

Note: The agitator even if in Auto cannot restart until operator resets the alarm manually.

If Agitator 07AG02 is not running (On-delay T=1s)Then Torque dilution controller JIC6085 is disabled with control valve FCV-

6085 forced closed.

(Above on-delay T=1s means that the interlock is reset 1s after Agitator is run-ning, enabling JIC6085 if in auto 1s after running status is obtained).

If Loop 2 Continuous Filtrate Pump 10PPC08 is not runningThen Torque dilution controller JIC6085 is disabled with control valve FCV-

6085 forced closed

If Agitator 07AG02 start order. If Torque controller JIC6085 in Auto

And Loop 2 Continuous Filtrate Pump 10PPC08 is run-ningThen Control valve FCV-6085 is opened to 60% for T1=15s

. If Dilution flow control FIC6060 in AutoAnd Loop 2 Continuous Filtrate Pump 10PPC08 is run-

ningThen Control valve FCV-6060 is opened to 60% for T2=15s

After T1, Agitator 07AG02 is started(When Agitator 07AG02 is running for 15s, JIC6085 is enabled)(When Extraction pump 07PPC07 is running for 1s, FIC6060 is enabled)



Note: There is no interlock preventing starting manually the bottom agitator without dilution - which is a wrong manoeuvre. If the stock in the lower part of the Tower has a high consistency, the High-High torque interlock will stop the agitator.

146- INTERLOCKS TO DILUTION FLOW CONTROLLER FIC6060

If Extraction pump 07PPC07 is not running (On-delay T1=1s)Then Flow dilution controller FIC6060 is disabled with control valve FCV-6060

forced closed.

If Loop 2 Continuous Filtrate Pump 10PPC08 is not runningThen Flow dilution controller FIC6060 is disabled with control valve FCV-6060

forced closed.

Note: There is no interlock preventing starting manually the pump without dilution - which is a wrong manoeuvre. If the stock in the lower part of the Tower has a high consistency, there is a risk to trip the mixer motor, block pump.

147- INTERLOCKS TO CONSISTENCY CONTROLLER NRC6095

If Extraction pump 07PPC07 is not running (On-delay T1=1s)Then Consistency dilution controller NRC6095 is disabled with control valve

NCV-6095 forced closed.

If Loop 2 Continuous Filtrate Pump 10PPC08 is not runningThen Consistency dilution controller NRC6095 is disabled with control valve

NCV-6095 forced closed.

If Mixer 07AG03 start orderWith Consistency controller NRC6095 is in AutoAnd Loop 2 Continuous Filtrate Pump 10PPC08 is running

Then Consistency dilution controller NCV-6095 is opened to 60% for T2=15sAfter T2=15s, Mixer 07AG03 is started

(Reset of above Extraction pump 07PPC07 interlock enables NRC6095 if in Auto)

Note: There is no interlock preventing starting manually the mixer or the pump without dilution - which is a wrong manoeuvre. If the stock in the lower part of the Tower has a high consistency, there is a risk to trip the mixer motor.



148- BLEACHING TOWER LEVEL LIS6070 HIGH_HIGH INTERLOCK TO DILUTION VALVES

If Oxidative bleaching tower 07CPA01 level is High-High

Then Torque dilution controller JIC6085 is disabled with valve FCV-6085 forced closed

And Flow dilution controller FIC6060 is disabled with valve FCV-6060 forced closed

And Consistency controller NRC6095 is disabled with valve NCV-6095 forced closed

Note: this interlock is designed to prevent adding dilution filtrates to a full tower, to prevent overflowing the tower filling it with filtrates.

149- EXTRACTION PUMP 07PPC07 to SLAVE VALVE 403-HS-6250

If Extraction Pump 07PPC07 is not runningThen Slave valve 403-HS-6250 is forced closed (Hard interlock)

If Extraction Pump 07PPC07 is runningWith On-delay T=5s,

Then Open Slave valve 403-HS-6250 (Hard interlock-with air exhaust limit to open in 15s)

Note: 403-HS-6250 in Manual or in Auto always operates with 07PPC07. The op-erator cannot operate the valve independently from the pump, even in Manual. Operation of the valve independently from the pump will require maintenance or engineer level access.

150- BLEACHING TOWER 07CPA01 LEVEL LIS6070 INTERLOCK TO AGITATOR 07AG02 & MIXER 07AG03

If Bleaching tower level LIS6070 is Low-Low

Then Stop Mixer 07AG03And Stop Agitator 07AG02

If Bleaching tower level LIS6070 is Low

Then Inhibit Start Extraction Mixer 07AG03And Inhibit Start Agitator 07AG02

If Bleaching tower level LIS6070 is Not LowAnd Agitator 07AG02 in DCS Auto mode




151- EXTRACTION PUMP 07PPC07 TO MIXER 07AG03

If Extraction Pump 07PPC07 is not runningAnd Mixer 07AG03 is running since T=300s

Then Mixer 07AG03 if running is stopped (hard interlock)

Note: this interlock stops the mixer to avoid "forgetting" the mixer running without flow for a long period. The interlock is active only after equipment is run-ning to allow starting the equipment.

152- INTERLOCKS TO EXTRACTION PUMP 07PPC07

If Loop 2 Continuous Filtrate Pump 10PPC08 is not runningThen Stop Bleaching Tower extraction pump 07PPC07

If Bleaching tower level LIS6070 is Low-LowOr Mixer 07AG03 is not runningOr Agitator 07AG02 is not running

Then Stop Bleaching Tower extraction pump 07PPC07

If Bleaching tower level LIS6070 is LowThen Inhibit Start Bleaching Tower extraction pump 07PPC07

153- FINE SCREENING FEED CHEST 07CPA08 LEVEL LIC6120 INTERLOCK TO EXTRACTION PUMP 07PPC07

If Fine Screening feed chest level LIC6120 is Alarm High-HighThen Extraction pump 07PPC07 is stopped (hard interlock)

If Fine Screening feed chest level LIC6120 is Alarm HighThen Extraction pump 07PPC07 is stopped (soft interlock)

154- (RESERVE)



1.38.6 ALARMS

155- SEALING WATER

If Thickening - Bleaching area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


156- COMPRESSED AIR

If Oxidative Bleaching area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


157- RECIRCULATION CHEST 07CPA11 LEVEL

If Recirculation chest 07CPA11 level controller LIC6007 is High


158- CLOUDY FILTRATE TANK 05CE02

If Loop 1 cloudy filtrate tank 05CE02 level controller LIS5045 is High


159- BLEACHING TOWER 07CPA01 LEVEL LIS6070

If Bleaching tower 07CPA01 level controller LIS6070 is High


160- (RESERVE)



1.39 OPERATION

1.39.1 Start-up

The Area Thickening-Kneading is the first system started in Loop 1 (after of course Water Distribution system).It starts only if the Ox Bleaching Tower 07CPA01 level is not High AND not Low-Low.



Low).- Steam network under pressure- “FRESH WATER” network under pressure - Chemicals ready- Loop 2 filtrate tanks Level LIC9050 & LIS9055 are not Low.- Bleaching tower 07CPA01 level LIS6070 is not High AND not Low-Low

Note: If Bleaching Tower 07CPA01 level is Low, operator needs to pre-fill the Tower with Loop 2 filtrates from pump 10PPC08.


The system is started by sequentially starting all elements from downstream to upstream.

If not already running, start Loop 2 filtrate pumps 10PPC08 & 10PPC09.

Start Kneader 06TL02.When running status is obtained, wait T=5s then proceed

Set ON Screw Press 06PVS01.

Set Screw Press Torque controller JICS6020 to MANUAL and 80% output.

Time delay 10 seconds.

Screw Press counter pressure cone solenoid valve deenergized

Start feed MC pump 05PMC10.All attached valves and controllers of sub-system - in Auto mode - start accord-ing to interlocks defined above:


The system is running.



1.39.1.2 Production

The process bloc starts in production with Flotation area: with the opening of valve FCV-3020at the outlet of the constant level box 02CP20.

The whole LOOP1 line is then started, and when stock arrives to Bleaching Tower 07CPA01. Operator then needs to set:

Screw Press Torque controller JICS6020 to AUTO and standard set point.

Kneader Counter-pressure ON.

With Interlocks, Kneader 06TL02 heating temperature controller TIC6025 will be enabled when allowed by Screw press 06PVS01.

Kneader CP_Status ON is required to allow Chemical dosage to Kneader.

Thanks to recirculation chest 07CPA11, it’s also possible to start Loop 1 in pro-duction with pulp without Screw Press and Kneader system: with On/Off valve AV-6010 closed and valve AV-6006, pulp from MC pump 05PMC10 feeds directly chest 07CPA11 and is sent backward to Dumping chest 01CPA15 via pump 07PPC13.


Monitoring of stock consistencies. Monitoring of Steam pressure Monitoring of drive motors load. Monitoring of Kneader 06TL02 specific energy Checking of Bleaching Tower level 07CPA01 (one of the main para-

meters in the line).



1.39.3 Shutdown


Loop 1 DIP line stops in production with the pre-flotation, fine cleaning and Disc Filter areas, by closing of the control valve FCV-3020 outlet of the constant level box 02CP20.

Provided there is no pulp flow to the Loop 1 Disc Filter, Thickening – Bleaching sub-system can be stopped.Waiting is provided to empty the system from the stock present for an adequate planned shut.


Thickening – Bleaching area is stopped after Disc Filter area.

Stop feed MC pump 05PMC10.

Set Kneader-CP to OFFWait T=60s then proceed

Energize solenoid valve of Screw Press counter pressure cone

Wait approx. T=60s (Screw Press is emptied from pulp)

Stop Screw Press 06PVS01Wait T=10s then proceed

Stop Kneader 06TL02

The system is stopped

Note: Tower extraction pump 07PPC07 is stopped when no more pulp is required on downstream process. This action is independent from upstream process stop sequence.



PROCESS DESCRIPTION


PRINTING - WRITING

FINE SCREENING

FINE SCREENINGPage 156/264


10 FINE SCREENING

1.40 DESCRIPTION


Fine screening feed chest........................................................................................07CPA08

Fine screening feed agitator.....................................................................................07AG09

Fine screen feed pump.............................................................................07PPC10

Fine slots screen (ScreenOne).................................................................................08SC01

Accept constant level box.........................................................................................08CP02

1.40.2 ScreenOne basics

1.40.2.1 ScreenOne Description

Refer to Loop 1 ScreenOne description (§ 1.15.2.1 – Page 65).

1.40.2.2 ScreenOne Operation

Refer to Loop 1 ScreenOne operation (§ 1.15.2.2 – Page 66).

1.40.2.3 ScreenOne sequence




1.40.3 Fine screening area

From the Bleaching tower 07CPA01, pump 07PPC07 feeds the stock chest 07CPA08 that is a constant level working chest.The level control LIC6120 commands the stock quantity required upstream the system via control valve LCV-6021 on stock feed pipe.

Feed chest 07CPA08 serves also to homogenize finely stock extracted from Bleaching step (in consistency, air content, …).

ScreenOne 08SC01 receives stock from pump 07PPC10 with stock at consist-ency ~3% regulated by controller NRC6125 and addition of Loop 2 filtrates from pump 10PPC08.

In fact, as dilution at this point requires a relatively big flow (at least more than ac-ceptable for a single injection to pump suction where consistency adjustment is better with limited flow variations), water dilution is made through controllers QC6126 and NRC6125 as follows:

Most part is directed (via control valve NCV-6126) towards feed chest 07CPA08.

Remaining dilution water flow is directed (via control valve NCV-6125) to suction of pump 07PPC10 where consistency reaches more finely 3%.

Controller QC6126 operates as a proportional ratio in order to adjust associated valves (NCV-6125 and NCV-6126) opening values, and then the sharing of total dilution flows (usually 70% of total flow through valve NCV-6126 and 30% through NCV-6125).

Pressure regulation loop PIC7090 (with control valve PCV-7090 on recirculating pipe back to feed chest 07CAP08) keeps constant ScreenOne feed pressure in order to avoid shocks (that could cause internal damages) during transitory phases (on ScreenOne start-up when automatic valve AV-7020 opens or during washing and unplugging sequences).We recommend inlet automatic valve AV-7020 to open slowly.

Screen inlet pressure is continuously controlled by control loop PIS7025.

Accepted stock A1 (from first slotted screening zone) is routed to accept constant level box 08CP02.Flow can be adjusted by controller FIC7085 and pressure is continuously con-trolled by loop PIS7030.An accidental plugging will be detected by differential pressure alarm PDIS7035 (ratio between inlet and accept A1 pressures).

Rejects from this first zone are diluted (via manual valve MV-7006) with white wa-ter. This dilution flow is measured by loop FIC7005.

Accepted stock A2 (from second slotted screening zone) is also routed to Con-stant level box 08CP02.Flow is adjusted by controller FFIC7080 in ratio with accept A1 flow (FIC7085) and according to required reject rates between each screening zones.



Stock pressure from accept A2 is continuously controlled by instrumentation loop PIS7050.An accidental plugging in 2nd screening zone will be detected by differential pres-sure alarm PDIS7055 (ratio between inlet and accept A2 pressures).

A water connection allows stock dilution between second and third screening zones. This dilution flow is indicated by loop FI7010 and may be adjusted at start-up with manual valve MV-7011.

Accepted stock A3 (from third slotted screening zone) is sent backwards to feed chest 07CPA08.

A3 accept Flow is adjusted by controller FFIC7075 in ratio with accept A1 flow (FIC7085) and according to required reject rates between each screening zones.Stock pressure from accept A3 is continuously controlled by instrumentation loop PIS7060.An accidental plugging in 3rd screening zone will be detected by differential pres-sure alarm PDIS7065 (ratio between inlet and accept A3 pressures).

Rejected stock from the third screening zone is also diluted before being directed to sewer.Reject dilution water flow is indicated by loop FI7015 and may be adjusted at start-up with manual valve MV-7016.

Stock rejected flow is adjusted by controller FFIC7070 in ratio with accept A1 flow (FIC7085) and according to required reject rates.

Dilution controller FIC7005 adds up all water dilution flows to ScreenOne and ad-justs the total (sum of measured flows FT-7005 + FT-7010 + FT-7015) according to operating dilution Set-Point (adjusted on start-up) by regulating opening value of control valve FCV-7005.The Low Flow Alarm for total water dilution calculations (i.e. measured total flow < 0,5 x set point) indicates a ScreenOne operation problem and is used to launch a Washing Sequence (see § 1.44.3.2 – Page 166).

In case of differential pressure alarms (for 1st screening zone, for the 2nd and for the 3rd) or in case of drive overload alarm (JISH7045), appropriate sequences are launched in order to clean the ScreenOne basket (see § 1.44.3 – Page 166).

Controller SIC2695 allows to adjust (manual set-point before start-up) and control speed of ScreenOne drive motor from DCS according to screen working condi-tions and then to save power consumption.

Stock outlet from constant level box 08CP02 is routed to downstream process (optional Post-Flotation)An overflow pipe from constant box 08CP02 to Feed chest 07CPA08 enables ScreenOne operation at constant rating (in flow and pressure), whatever the pro-duction variations.




ScreenOne: Size SO8- Area 1: Slots 0,15mm. Accept flow = ~450 m3/h at consistency 2,5-3%.- Area 2: Slots 0,15mm. Accept flow = ~125 m3/h at consistency 2-2,5%.- Area 3: Slots 0,15mm. Accept flow = ~30 m3/h at consistency 2%.

Total accept production (A1 + A2) = 370 BDT/24h




LIC 6120 Feed chest 07CPA08 level control 5% 15% 85% 95% 0-70 m3

NRC 6125Slots pre-screening feed consistency control

2,5 to 5%

QC 6126Ratio repartition for Fine screening feed dilution water flow

0-100%

PIC 7090ScreenOne 08SC01 feed pressure con-trol

0–4 Bars

FIC 7005 ScreenOne 08SC01 dilution flow control

FT-7005: intermediate dilution flow meas-urement (between 1st & 2nd zones)

0-50 m3/h

FC-7005: ScreenOne total water dilution flow controller

= (FT-7005 + FT-7010 + FT-7015)

L

(1)0-150 m3/h

FCV-7005: total dilution flow valve 0-150 m3/h

FI 7010ScreenOne 08SC01 intermediate dilution flow indication (between 2nd & 3rd screen-ing zones)

0-75 m3/h

FI 7015ScreenOne 08SC01 reject dilution flow indication

0-75 m3/h

PIS 7025ScreenOne 08SC01 inlet pressure indic-ation

3

(1)0–4 Bars



0,4

(1)

0,6

(1)0–2 Bars


1

(1)0–4 Bars

…/…







0,4

(1)

0,6

(1)0–2 Bars


1

(1)0–4 Bars



0,4

(1)

0,6

(1)0–2 Bars


1

(1)0–4 Bars

FFIC 7070 ScreenOne 08SC01 reject flow control 0-75 m3/h


0-100 m3/h


0-250 m3/h

FIC 7085ScreenOne 08SC01 Accept A1 flow con-trol

0-500 m3/h

SIC 7040ScreenOne 08SC01 drive motor speed control

0-100%

JISH 7045 ScreenOne 08SC01 drive Amp Load 95% 100% 0-150%





161- BLEACHING TOWER EXTRACTION PUMP 07PPC07 TO FINE SCREENING FEED CHEST LEVEL LIC6120

If Bleaching tower extraction pump 07PPC07 is not running

Then Chest feed control valve LCV-6021 is forced closed.

162- FINE SCREENING FEED CHEST LEVEL LIC6120 TO AGITATOR 07AG09

If Fine Screening feed chest level LIC6120 is Low-LowThen Stop Agitator 07AG09

If Fine Screening feed chest level LIC6120 is LowThen Inhibit Start Agitator 07AG09

If Fine Screening feed chest level LIC6120 is not LowAnd Agitator 07AG09 in DCS Auto mode


163- INTERLOCKS TO FINE SCREENING FEED PUMP 07PPC10

If Fine Screening feed Chest level LIC6120 is LowOr ScreenOne 08SC01 is not runningOr Loop 2 Continuous water dilution pump 10PPC08 is not running

Then Screening feed pump 07PPC10 is stopped.

If Fine Screening feed Chest level LIC6120 is Low

Then Inhibit start of Screening feed pump 07PPC10

164- INTERLOCKS FROM FINE SCREENING FEED PUMP 07PPC10 TO SLAVE VALVE AV-7020

If Screening feed pump 07PPC10 is not runningThen On/Off slave valve AV-7020 is forced closed

If Screening feed pump 07PPC10 is runningThen With on delay T=5s, On/Off slave valve AV-7020 in Auto opens (air ex-




165- INTERLOCKS TO DILUTION CONTROLLERS NRC6125 & QC6126

If Screening feed pump 07PPC10 is not runningOr Loop 2 Continuous water dilution pump 10PPC08 is not running

Then Dilution controllers NRC6125 & QC6126 are disabled with control valves NCV-6125 & NCV-6126 forced closed.

166- (RESERVE)

167- (RESERVE)

ALARMS

168- SEALING WATER

If Fine Screening area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


169- COMPRESSED AIR

If Fine screening area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


170- (RESERVE)



1.44 OPERATION

1.44.1 Start-up

Normal start-up operation will lead to start Loop 2 fine screening after Post-Flota-tion.It is possible to start Fine Screening independently of the Post-Flotation, recircu-lating back from constant level box 08CP02: this will lead to overflow Feed Chest 07CPA08.

1.44.1.1 Fill the unit

Starting up the fine screening loop begins with the filling phase of the unit:



Low).- Level control LIS9055 of water tank 10CE06 is not Low.

If not already running, start Loop 2 Continuous water pump 10PPC08.

Open ScreenOne sealing water valve SV-19382.

Start of ScreenOne cycle, whose first step is the filling phase (refer to specific Function Chart). :

Open reject valve FCV-7070 up-to its “X%" opening value. This posi-tion must allow water filling with a moderate pressure inside Screen-One.

Open water dilution valve FCV-7005 during a pre-set time (to be adjus-ted at start-up, usually 30 seconds).

Start of ScreenOne 08SC01 motor.

Note: The unit working in cycle automatically go over to the working configuration at the end of filling time (controlled by timer set on start-up of the installation and taking account of the size of the unit and of pressures and flow rates available in the water circuits).




Start transfer pump 07PPC07 with activation of level controller LIC6120 in order to fill feed chest 02CPA16 with pulp.

When a sufficiently level is reached (usually higher than 40%):

Start ScreenOne feed pump 07PPC10 with activation of pressure con-troller PIC7090.

Note 1: As long inlet valve AV-7020 is not open, pulp pumped by 07PPC10 flows back to feed chest 07CPA08 via control valve PCV-7090 fully open.Note 2: With interlocks, consistency controller NRC2610 is set on automatic.

Open slowly ScreenOne inlet valve AV-7020. Reject flow control loop FFIC7070 is activated (valve FCV-7070 moves

from full opening to operating value). Accept A3 flow control loop FFIC7075 is activated. Accept A2 flow control loop FFIC7080 is activated. Accept A1 flow control loop FFIC7085 is activated.

1.44.1.3 Production


DIP line Loop 2 starts in production when the stock is bled downstream of the constant level box 08CP02to Post-Flotation with opening of valve FCV-8010.

1.44.2 Operation

To be monitored during the operation of the installation: Inlet and accepts pressures of screens. All Consistencies. Regularity of Flows through ScreenOne. Regularity of the power absorbed by the ScreenOne.



1.44.3 Sequences

This chapter hereunder is only for description.Please refer to associate Function Chart (to be supplied by Kadant) for exact se-quence to be programmed.

1.44.3.1 ScreenOne basket depluging

This sequence is launched in case of Differential pressure High alarm on threshold 1 (PDSH7035 for 1st screening zone, PDSH7055 for the 2nd and PDSH7065 for the 3rd) for T= 5 to 10 seconds.

Open reject valve FCV-7070 to its “X%" opening value. Close Accept control valve at screening stage in Alarm and Accept

control valve at eventual backward stages.

Examples: On Alarm PDSH7065, cleaning of basket 3rd zone will close control valve

FCV-7075 for the 3rd stage.On Alarm PDSH7055, cleaning of basket 2nd zone will close control valves

FCV-7080 for the 2nd stage and valves FCV-7075 for the 3rd stage.On Alarm PDSH7035, cleaning of basket 1st zone will close control valves

FCV-7085 for the 1st stage, FCV-7080 for the 2nd stage and valves FCV-7075 for the 3rd stage.

After a pre-set timer (adjusted during start-up, usually 60 seconds): re-ject valve FCV-7070 and accept control valves come back to their automatic position.

1.44.3.2 ScreenOne washing

During ScreenOne normal operation, this sequence is launched in case of: An overload of the ScreenOne motor, detected by alarm JISH7045 OR a differential pressure High-High alarm on threshold 2 (PDSHH7035

for 1st screening zone, PDSHH7055 for the 2nd and PDSHH7065 for the 3rd) for T= 5 to 10 seconds.

OR a Low alarm of total dilution water flow to ScreenOne (calculated by controller FC7005 < 0,5 x set point) during T=5 to 10s.

OR a ScreenOne stop request in AUTOMATIC mode. OR an Operator manual request (key “WASH”)

Close stock feed valve AV-7020. Close accept flow valves (FCV-7085 for accept A1, FCV-7080 for ac-

cept A2 & FCV-7075 for accept A3). Open reject valve FCV-7070 to its “X%" opening value. After a pre-set timer (usually 30 seconds), sequence proceeds either

back to working operation or to stop (if requesting in AUTO mode).



1.44.4 Shutdown


The process bloc stops in production when no more pulp required in downstream Post-Flotation area, with closing of weight valve FCV-8010 on accept constant level box 08CP02 outlet pipe.


Please refer to associated function chart (will be supplied by Kadant) including “stop step” for ScreenOne:

A Washing sequence is launched (See § 1.44.3.2)At the end of this sequence, inlet valve AV-7020 remains closed and reject valve FCV-7070 remains to its “X%" opening value.

Stop feed pump 07PPC10 motor.With interlocks, dilution controllers NRC6125 & QC6126 are dis-abled.

Opening of reject valve FCV-7070 in fully opened position. Closing (slowly with a ramp) of accept A1 valve FCV-7085. Closing (slowly with a ramp) of accept A2 valve FCV-7080. Closing (slowly with a ramp) of accept A3 valve FCV-7075. Stop of ScreenOne motor. Closing of water valve FCV-7005.



PROCESS DESCRIPTION


PRINTING - WRITING

POST-FLOTATION AREA

POST-FLOTATIONPage 168/264


11 POST-FLOTATION

1.45 DESCRIPTION

1.45.1 Post-Flotation Itemization

Deinking 1st aeration feed pump..............................................................................09PPC01

Deinking 2nd aeration feed pump............................................................................09PPC03

Deinking 3rd aeration feed pump.............................................................................09PPC04

Deinking 4th aeration feed pump.............................................................................09PPC05

Flotation cell (MAC) .............................................................................09CEV02

Flotation accept constant level box..........................................................................09CP08

Foam tank .............................................................................09CPA06

Deinking foam transfer pump...................................................................................09PPV07

1.45.2 Flotation cell (MAC) basics

Refer to Pre-Flotation description (§ 1.20.2 – Page 79).

1.45.3 Deinking cell MAC Sequence




1.45.4 Post-Flotation area

Deinking cell feed

The stock coming from the Fine screening constant level box 08CPA02 is pumped to flotation cell MAC through 1st aeration pump 09PPC01 connected on water tank 10CE05 to ensure necessary dilution.

Flowmeter FIC8010 adjusts flotation stock feed flow.Control valve FCV-8010 is the basis weight valve for 2nd loop of deinking line: its opening fixes the production rate of Loop 2 in concordance with stability of level in Bleaching Tower 07CPA01.

A chemicals injection (surfactant), connected at pump 09PPC01 suction, allows adjusting post-flotation operation according to process conditions and required efficiency.

1st aeration pump 09PPC01 feeds canister of injectors of the cell’s first stage, at the pressure required (1,4 bars normally), and continuously measured by trans-mitter PIS8055, to ensure air suction and mixing of bubbles in the stock. Manual valve MV-8067 at the pump discharge is meant to adjust the inlet pres-sure and thus the operating flow of the cell.

The size of canisters depending on the construction, their throughput will only de-pend on their inlet pressure. Each canister of injectors features:

A stock inlet, An outlet for the stock/air mix, A washing water inlet to fill the canister of injectors during start-up, shut-

down or washing, An inlet for air injected into the stock and also used for the discharge to

sewer of the washing water.The canister’s washing water connection nipples have automatic isolating valves used during the various operating sequences.

Stock aerated in this way flows in the first stage in the top of the cell where separ-ation of air bubbles from the stock takes place.

Multi-aeration principle

Stock is then taken up in a pipe in the central barrel to flow out at the cell’s lower part so as to feed the 2nd aeration.

2nd aeration pump 09PPC03 feeds 2nd canister of injectors, identical to the previ-ous one.Hand valve MV-8038 at the pump discharge enables to adjust the inlet pressure of the 2nd aeration canister of injectors (pressure is continuously measured by transmitter PIS8045). Stock flows in the cell at a level lower than the one of the previous stage.

Stock will circulate in the same way for the subsequent aeration steps:- 3rd aeration pump 09PPC04.- 4th aeration pump 09PPC05.



Accept constant level box

After the last aeration stage at the lower part of the cell, stock goes up to con-stant level box 09CP08 at a higher level than the top of the cell. Thus the cell is statically and steadily pressurized and floated stock flows out freely.

From this constant level box, stock is routed by gravity to a further process stage.Constant level box can also send the stock back to the suction of 1 st aeration pump 09PPC01.This recycling flow is adjusted by HIC8005 during normal operation (where recir-culating flow is to be set between 0 and 15% maxi of Flotation design flow).Moreover a parallel bigger pipe, equipped with On/Off Valve AV-8006, allows to recirculate back all flotation accept flow from constant box 09CP08 if needed by a transitory phase (for example adjustment on start-up or an eventual incident).

This configuration of circuit enables Post-Flotation operation at constant rating, whatever the production in downstream process.

The flow through injectors being set by the inlet pressure required for their proper operation, the flow through the cell is firm.

Due to its principle and inner construction, the Primary flotation cell (MAC)’s pro-duction is only fixed by the feed pump. The other aeration pumps can run or be turned off without affecting the production flowing through the cell. They only af-fect stock quality insofar as their role is just limited to aerating stock via the inject-ors.

Deinking cell foam

MAC cell 09CEV02 foam level is regulated by level controller LIC8090 with PIS8090 (refer to regulation principle in Kadant Function Charts).The cell level means the stock level in the cell, i.e., the position of the interface between the stock (at the lower part) and the foam (at the top part).


Post-Flotation cell MAC 09CEV02 is equipped with a foam washing device: A water injection controlled by flow regulation loop FIC8080 enables to

“wash” ink foam collected at cell top part and then allows to recover re-sidual stock fibers that could be hung on foam bubbles.

Resulting excess flow coming out from 1st stage is recycled to 1st aera-tion pump 09PPC01 suction through flow-meter FFIC8015. Of course this excess flow is directly proportional to additional washing flow FIC8080.

Foam is discharged through piping at the cell’s lower part. This piping is fitted with control valve LCV-8090, ensuring both level control in the cell and relaxing of foam, which is thus discharged as liquid to sludge tank.



Foam tank 09CPA06 and foam recirculation to Prime MAC

Post-flotation deinking foam is extracted from tank 09CPA06 with volumetric pump 09PPV07.

As already explained for Pre-Flotation, Loop 1 Prime MAC 03CEV02A gives the opportunity to re-introduce a part (adjustable) of deinking foam in order to reduce fiber losses and increase plant yield.This re-introduction flow is to be adjusted with manual valve MV-3154 (on trans-fer pipe to Prime MAC feed pump 03PPC01 suction) and in relation with required pulp final quality.

Pump 09PPV07 is equipped with a variable speed motor in order to adapt extrac-tion flow to Foam tank 09CPA06 level LIC8095.

Moreover pressure controller PIC8100 allows to send to sludge treatment the re-maining foam flow, which is the difference between foam flow extracted from cell 09CEV02 MINUS flow sent back to Prime MAC (through valve MV-3154).

In order to avoid running of volumetric pump 09PPV07 with all outlet valves closed (that could cause definitive damage to pump mechanism), manual valve MV-3154 must be equipped with an adjustable limit switch, to be set very care-fully on start-up with a minimum opening (maybe 10%) compatible with volumet-ric pump highest operating pressure.Then this limit switch will be used to interlock the start of volumetric pump (See Interlock N° 177- Page 175).

And for more security, in case of operation with no recirculation to Prime MAC (On/Off valve AV-3140 closed), control valve PCV-8100 is forced open and all Post-Flotation foam is transferred to sludge treatment (transfer flow is then dir-ectly regulated by tank level control LIC8095 acting on pump 09PPV07 speed controller SC8095).




Post-Flotation MAC cell 4 aerations: MAC 4W1456Inlet flow 1456 m3/h at consistency 1,2% (i.e. 400

BDMT/24h)




HIC 8005Control of deinking cell 09CEV02 accept recycling

0-100%

FIC 8010Flow control of stock sent to Post-flota-tion

0-650 m3/h

PIS 8055Post-flotation cell 09CEV02 Stage 1 feed pressure indication

1 2 0–3 Bars


1 2 0–3 Bars


1 2 0–3 Bars


1 2 0–3 Bars

FIC 8080Flow control of Post-flotation cell foam washing water

0-300 m3/h

FFIC 8015Flow control of 2nd aeration stock recyc-ling to 1st aeration feed pump

0-300 m3/h

PIS 8090Pre-flotation cell 09CEV02 inside pres-sure indicator

1 0–3 Bars

LIC 8090Pre-flotation cell 09CEV02 inside foam level control

0-100%


SIC 8095Foam pump 09PPV07 motor speed con-trol

0-100%

PIC 8100Pressure control of Post-Flotation foam transfer to sludge treatment

0–4 Bars




171- INTERLOCKS to CELL 1st AERATION FEED PUMP 09PPC01

If Water tank 10CE05 level controller LIS9050 is lowOr MAC cell inside pressure is High (LIC8090 level High)

Then 1st aeration pump 09PPC01 is stopped.

172- 1st AERATION FEED PUMP 09PPC01 to DEINKING CELL LEVEL CONTROL-LERS PIS8090 & LIC8090

If 1st aeration pump 09PPC01 is not runningThen Controllers PIS8090 & LIC8090 are disabled with LCV-8090 forced

open.

173- 1st AERATION FEED PUMP 09PPC01 to SLAVE ON/OFF VALVE AV-8068

If 1st aeration pump 09PPC01 is not runningThen On/Off Valve AV-8068 is forced closed

If 1st aeration pump 09PPC01 is runningThen With on delay T=5s, On/Off Valve AV-8068 in Auto is opened (air ex-


174- OTHER INTERLOCKS from 1st AERATION FEED PUMP 09PPC01


Then Stock feed control valve FCV-8010 is forced closedAnd Flotation accept constant box 09CP08 recycling control valve HCV-8005

and On/Off Valve AV-8006 are forced closedAnd Recycling flow controller (from 2nd stage) FFIC8015 is disabled with con-

trol valve FCV-8015 forced closedAnd Chemicals supply to feed pump suction is disabled



175- INTERLOCKS to CELL OTHER AERATION FEED PUMPS


Then 09PPC03 is forced stopped (2nd Aeration)Then 09PPC04 is forced stopped (3rd Aeration)Then 09PPC05 is forced stopped (4th Aeration)

If Deinking Cell level LIC8090 is Low (meaning Cell inlet pressure is High)

Then Inhibit start of pump 09PPC03 (2nd Aeration)Then Inhibit start of pump 09PPC04 (3rd Aeration)Then Inhibit start of pump 09PPC05 (4th Aeration)

176- SLUDGE TANK LEVEL LIC8095 to EXTRACTION PUMP 09PPV07

If Sludge tank 09CPA06 level LIC8095 is Low

Then Stop sludge transfer pump 09PPV07

177- SECURITY INTERLOCKS FROM VOLUMETRIC PUMP 09PPV07

If On/Off valve AV-3140 is not open (Full Open limit switch not activated)Or Manual valve MV-3154 minimum opening limit switch is not activated

(Valve opening adjustment to Low)While MAC cell feed pump 09PPC01 is running

Then Control valve PCV-8100 is forced to fully open

If On/Off valve AV-3140 is not open (Full Open limit switch not activated) And Control valve PCV-8100 is not fully open

Then Volumetric pump 03PPV10 is forced stopped

178- (RESERVE)

179- (RESERVE)



ALARMS

180- SEALING WATER

If Post-Flotation area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


181- COMPRESSED AIR

If Post-Flotation area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


182- (RESERVE)



1.49 OPERATION

1.49.1 Start up

1.49.1.1 Water filling

Basic conditions:- Compressed air system is under pressure (pressure PIA19202 not on Alarm

Low).- Post-flotation cell 09CEV02 foam valve LCV-8090 must be open

Water tank 10CE05 level controller LIC9050 must be highStock feed valve FCV-8010 is closedRecycling valve HCV-8005 is closed

Vent valve AV-8085 on the top of the cell is normally open.

Start 1st aeration pump 09PPC01. (With Interlocks valve AV-8068 after T=5 sec).

Water valve AV-8075 of the 1st stage canister of injectors opens during T=15 sec.

When the cell is full, detected by level controller LIC8090 High:

Close vent valve AV-8085 on the top of the cell.

Stop 1st aeration pump 09PPC01 (With Interlocks valve AV-8068 will close auto-matically).

1.49.1.2 Starting of loop

Aeration 4: Start 4th aeration feed pump 09PPC05 Open air valve AV-8025 for 4th aeration of cell 09CEV02 Water valve AV-8030 on canister opens during T=15 sec and closes.

Aeration 3: Start 3rd aeration feed pump 09PPC04 Open air valve AV-8060 for 3rd aeration of cell 09CEV02 Water valve AV-8065 on canister opens during T=15 sec and closes.

Aeration 2: Start 2nd aeration feed pump 09PPC03 Open air valve AV-8040 for 2nd aeration of cell 09CEV02 Water valve AV-8050 on canister opens during T=15 sec and closes.

Aeration 1: Start 1st aeration feed pump 09PPC01 Open air valve AV-8070 for 1st aeration of cell 09CEV02 Water valve AV-8075 on canister opens during T=15 sec and closes.

Set to AUTO mode flotation cell 09CEV02 level regulation LIC8090.



After some minutes of operation, successively flush each canister of injectors for a few seconds against possible stock deposits that may appear during the start-up phase.

1.49.1.3 Production

Foam transfer pump 03PPV07 is allowed to start through interlocks.Note: On/Off valve AV-3140 will be enabled to open only after Prime MAC feed pump 03PPC01 motor start.

Set to AUTO mode flotation stock feeding flow controller FIC8010.

Deinking foam washing controller FIC8080 can be set in Auto (flow set-point to be adjusted according to desired Fiber content in deinking foam) after a timer to be pre-set before start-up.

Simultaneously recycling Flow controller FFIC8015 is automatically set in Auto.

1.49.2 Operation

Monitoring of inlet pressures within the canisters of injectors.Monitoring of consistencies of inlet stock, accept stock and deinking foam for each cell.

Regularly at a rate that will be determined by the operation: Open level control valve LCV-8090 to raise the level within each cell

and clean the upper part of the cell. This operation will last a few seconds after which level controller will take its normal course of opera-tion.

Flush each canister of injectors successively, for a few seconds, against possible stock deposits.



1.49.3 Stop

1.49.3.1 Stop of loop

Disable foam washing flow controller FIC8080 with valve FCV-8080 forced closed.Automatically recycling Flow controller FFIC8015 is disabled with valve FCV-8015 forced closed.

Close the Post-Flotation feed stock valve FCV-8010 at the outlet of constant level box 02CP20.

Close recycling valve HCV-8005.

1.49.3.2 Stop of the Deinking cell

Execute the washing sequence for each injectors canister (on operator order).

Stop Aeration 1: Close air valve AV-8070 for 1st aeration of cell 09CEV02 Water valve AV-8075 on canister opens during T=15 sec and closes. Stop 1st aeration feed pump 09PPC01

Set to MANU mode Post-Flotation MAC cell 09CEV02 level regulation LIC8090 and open fully foam valve LCV-8090.

Open vent valve AV-8085 on the top of the deinking cell.

Stop aeration 2: Close air valve AV-8040 for 2nd aeration of cell 09CEV02 Water valve AV-8050 on canister opens during T=15 sec and closes. Stop 2nd aeration feed pump 09PPC03

Stop aeration 3: Close air valve AV-8060 for 3rd aeration of cell 09CEV02 Water valve AV-8065 on canister opens during T=15 sec and closes. Stop 3rd aeration feed pump 09PPC04

Stop aeration 4: Close air valve AV-8025 for 4th aeration of cell 09CEV02 Water valve AV-8030 on canister opens during T=15 sec and closes. Stop 4th aeration feed pump 09PPC05



PROCESS DESCRIPTION


PRINTING - WRITING

LOOP 2 DISC FILTER& WATER DISTRIBUTION



12 LOOP 2 DISC FILTER & WATER DISTRIBUTION

1.50 DESCRIPTION


Loop 2 Desaeration chest........................................................................................10CPA01

Loop 2 Desaeration chest agitator...........................................................................10AG02

Loop 2 Disc Filter feed pump...................................................................................10PPC03

Disc Filter .............................................................................10FDQ04

Clear filtrate tank ...............................................................................10CE06

Cloudy filtrate tank ...............................................................................10CE05

Pulper water transfer pump .....................................................................................05PPC05

Disc Filters showers feed pump ..............................................................................10PPC07

Loop 2 continuous water dilution pump ...................................................................10PPC08

Loop 2 periodic water dilution pump ........................................................................10PPC09

Loop 2 filtrate transfer pump to Micro-flotation.........................................................10PPC10

Dilution pump to recirculation chest 07CPA11.........................................................10PPC13

1.50.2 Disc Filter basics

Same description as Disc Filter in Loop 1 (See § 1.30.2 – Page 115).




1.50.3.1 Desaeration chest 10CPA01

Stock accepted from Post-Flotation is accepted by gravity from Level Box 09CP08 into Desaeration chest 10CPA01.

Desaeration chest 10CPA01 is operated at constant level via level controller LICS9005 with control valve LCV-9005 on feed pipe to Disc Filter 10FDQ04.By this way, Disc Filter operates at the same production than Post-Flotation ac-cept.

Desaeration chest 10CPA01 allows the air remaining in stock pulp to escape and is equipped with an agitator 1AG02.

1.50.3.2 Loop 2 Disc Filter

The Loop 2 Disc Filter 10FDQ04 thickens the pulp flow accepted from Post-Flota-tion system, from 1% to 10-12%.

Pulp pH on feed to Loop 2 Disc Filter is measured by transmitter AIR9010 and displayed/recorded.

Brightness on feed to Loop 2 Disc Filter is measured by transmitter AIR9015 and displayed/recorded.

The Disc Filter main drive speed controller SIC9025 maintains the level LIC9020 in Disc Filter 10FDQ04 vat.

This is the only control on the Disc Filter:- When the hydraulic through-put fed to the disc filter increases, leading to in-

crease the pulp level in the vat, the Disc filter drive speed increases.- When the hydraulic through-put fed to the disc filter decreases, leading to in-

crease the pulp level in the vat, the Disc filter drive speed decreases.

The filtrate supply to the Disc Filter showers, from its own Clear filtrates for both oscillating showers and Knock-off showers, is switched on by actuating On/Off valve AV-9035.Pressure indicator PI9030 on filtrates supply line to Knock-off shower ensures the adequate pressure is available.The respective shower flows are adjusted by setting of manual valves.

Transmitter PI9045 measures vacuum available for Disc Filter operating in Clear filtrate barometric leg.

A speed switch SS9040 supervises the Repulping Screw 10FDQ04b rotation.

The accepted 10-12% stock feeds downstream process (i.e. Reductive Bleach-ing).



The Shower pump 10PPC07 ensures the cleaning & unplugging of the Disc Filter sectors wire, using the Disc Filter's own clear filtrates.

1.50.3.3 Loop 2 water distribution

The Loop 2 Filtrate distribution system ensures the filtrate requirements for Loop 2 are covered.

Clear Filtrate tank 10CE06This tank receives:

Clear filtrate extracted from Disc Filter 10FDQ04. Complement water from loop 3 water pump 13PPC09 (through control

valve LCV-9050). Loop 3 filtrates (through On/Off valve AV-9085) from water pump

13PPC11, used for Loop 2 water tanks filling on start-up and for transfer of Clarified Water (when Micro-Flotation is fed with Loop 2 filtrates).

This tank level is measured by LIS9055.

Tank 10CE06 is used to feed: Loop 2 Continuous water pump 10PPC08 Loop 2 Periodic water pump 10PPC09 Disc Filter showers pump 10PPC07 Filtrates transfer pump 10PPC10

In case deashing system is not activated (DNT washers 13LAV02 & 13LAV03 are stopped), it is possible to operate Micro-flotation (free from DNT filtrate) with Loop 2 filtrates:

Pump 10PPC10 transfers Loop 2 Clear Filtrates to Loop 3 tank 13CE07 with a flow regulated by level controller LIC13010.

From Loop 3 clarified water tank 13CE08, pump 13PPC11 transfers back clarified water to Clear filtrate tank 10CE06.

Make-up water to Loop 2 water system is always made from pump 13PPC09 through level control valve LCV-9050.

A continuous overflow to Cloudy water tank 10CE05 allows a constant level of water and then avoids pressure variations at connected pump suctions, and transfers complement to downstream water tanks.

Cloudy Filtrate tank 10CE05This tank receives:

Cloudy filtrate extracted from Disc Filter 10FDQ04 Loop 2 Screw-press 11KR01 filtrates Overflow from Clear Water tank 10CE06

Tank 10CE05 is used for: Dilution of Post-flotation feed pump 09PPC01 Feed of dilution pump 10PPC13 Loop 2 Periodic water pump 10PPC09



Loop 2 Periodic water pump 10PPC09 can be fed either from Clear filtrate 10CE06 (through manual valve MV-9024) or from Cloudy filtrate tank 10CE05 (through manual valve MV-9053).The selection between these 2 possibilities is to be done according to water bal-ance in Loop 2 involved by line operation process.

In case of Loop 1 or Loop 2 accept pulp recirculation to chest 07CPA11 during transitory phase (like start-up for example), pump 10PPC13 is used to decrease transfer stock consistency from 10 to 4-5%.

Loop 1 pulp dilution is made through On/Off valve AV-6160 at MC pump 05PMC10 outlet (See § 1.35.6.2 – Page 137).

Loop 2 pulp dilution is made through On/Off valve AV-6155 at MC pump 14PMC03 outlet (See § 1.55.4.3 – Page 197).

Level of tank 10CE05 is controlled by loop LIC9050 acting on control valve LCV-9050 on make-up water from Loop 3 Filtrates pump 13PPC09, falling in Clear Fil-trate tank 10CE06 and overflowing to tank 10CE05.This configuration enables Low level LIS9055 to call also for water complement in case of water deficit water tank 10CE06.




Disc Filter: Ø 5200mmInlet flow 1370 m3/h at consistency 1% (i.e. 370 BDMT/

24h)




LIC 9005Desaeration chest 10CPA01 level con-trol

10% 15% 80% 90% 0-120 m3

AIR 9010PH indication of Loop 2 Disc Filter feed pulp

5 to 11

AIR 9015Brightness indication of Loop 2 Disc Fil-ter feed pulp

LIC 9020 Disc Filter 10FDQ04 vat level control 50% 95% 100% 0-100%

SS 9027Disc Filter 10FDQ04 main drive zero speed alarm

* Digital alarm

SIC 9025Disc Filter 10FDQ04 main drive zero speed alarm

0-100%

SS 9040Disc Filter Repulper rotation alarm Speed switch

* Digital alarm

PI 9030Disc Filter 10FDQ04 shower header pipe pressure indication

3,2 7 0–8 Kg/cm2g

PI 9045Disc Filter 10FDQ04 Clear Filtrate va-cuum indication

200 275- 600 to 0 mm HG

LIC 9050Cloudy filtrate tank 10CE05 level con-trol

10% 15% 80% 90% 0-60 m3

LIS 9055 Clear filtrate tank 10CE06 level control 10% 25% 0-60 m³




1.53.1 Desaeration chest 10CPA01

183- DESAERATION CHEST LEVEL LIC9005 TO AGITATOR 10AG02

If Desaeration chest level LIC9005 is Low-Low

Then Stop Agitator 10AG02

If Desaeration chest level LIC9005 is Low

Then Inhibit Start Agitator 10AG02

If Desaeration chest level LIC9005 is not LowAnd Agitator 10AG02 in DCS Auto mode


184- INTERLOCKS TO DISC FILTER 2 FEED PUMP 10PPC03

If Desaeration chest 10CPA01 level controller LIC9005 is Low-LowOr Disc Filter 10FDQ04 is not running

Then Loop 2 Disc Filter feed pump 10PPC03 is stopped.

If Desaeration chest 10CPA01 level controller LIC9005 is LowOr Disc Filter 10FDQ04 is NOT Ready

Then Inhibit start of Disc Filter feed pump 10PPC03.

185- INTERLOCKS FROM DISC FILTER 2 FEED PUMP 10PPC03

If Loop 2 Disc Filter feed pump 10PPC03 is not running

Then Slave control valve LCV-9005 is forced closed

If Loop 2 Disc Filter feed pump 10PPC03 is running

Then With On-Delay T=5s, Open control valve LCV-9005 (air exhaust limit to open 15s)



1.53.2 Loop 2 Disc Filter 10FDQ04

186- HEATING SCREW 14VIT01 TO DISC FILTER 10FDQ04

If Heating screw 14VIT01 is not running

Then Disc Filter Repulping Screw is stopped.

187- INTERLOCKS TO DISC FILTER REPULPER SCREW 10FDQ04b

If Disc Filter Repulping screw 10FDQ04b is running with start-up override T=5s

And Speed switch SS9040 is alarm (zero)

Then Disc Filter Repulping screw 10FDQ04b is stopped and alarm generated.

188- DISC FILTER OUTLET SCREW MOTOR TO SHOWERS WATER PUMP

If Motor (M6070) of Disc Filter discharge screw is running

Then Showers water pump “10PPC07” (M6072) is allowed to start

189- SHOWERS PUMP TO SHOWER OSCILLATING DEVICE MOTOR

If Showers water pump “10PPC07” is not running or tripped

Then Filter oscillating shower device motor (M6071) is forced to stop

190- INTERLOCKS TO DISC FILTER MAIN MOTOR

If Filter oscillating shower device (M6071) is not running or tripped


If Repulper drive motor (M6070) is not running or tripped


If Main Motor (M6069) of Disc Filter is runningAND Filter zero speed switch “SS-9027” is on alarm Low

Then Stop main motor (M6069) of Disc Filter



191- INTERLOCKS FROM DISC FILTER 10FDQ04

If Disc Filter Main Motor “M6069” is tripped during running

Then Filter vat level controller “LICA-9020” is DISABLEDAND Stock feeding pump “10PPC03” is forced to STOP

192- (RESERVE)

1.53.3 Loop 2 water distribution

193- INTERLOCKS TO SHOWERS WATER PUMP 10PPC07

If Clear filtrate tank 10CE06 level LIS9055 is Low-LowOr Disc Filter 10FDQ04 main motor is not running

Then Disc Filter shower pump 10PPC07 is stopped.

If Clear filtrate tank 10CE06 level LIS9055 is LowThen Inhibit start of Disc Filter shower pump 10PPC07

194- SHOWERS WATER PUMP 10PPC07 TO DELIVERY VALVE AV-9035

If Disc Filter shower pump 10PPC07 is not runningThen On/Off slave valve AV-9035 is forced closed

If Disc Filter shower pump 10PPC07 is runningThen With on delay T=5s, On/Off slave valve AV-9035 in Auto opens (air ex-


195- INTERLOCKS TO LOOP 2 CONTINUOUS WATER PUMP 10PPC08

If Clear filtrate tank 10CE06 level LIS9055 is Low-LowThen Continuous water pump 10PPC08 is stopped.

If Clear filtrate tank 10CE06 level LIS9055 is LowThen Inhibit start of Continuous water pump 10PPC08



196- LOOP 2 CONTINUOUS WATER PUMP 10PPC08 TO SLAVE VALVE AV-9080

If Continuous water pump 10PPC08 is not runningThen On/Off slave valve AV-9080 is forced closed

If Continuous water pump 10PPC08 is runningThen With on delay T=5s, On/Off slave valve AV-9080 in Auto opens (air ex-


197- INTERLOCKS TO LOOP 2 PERIODIC WATER PUMP 10PPC09

If Clear filtrate tank 10CE06 level LIS9055 is Low-LowWhile pump 10PPC09 is fed from tank 10CE06 (through manual valve MV-9024)

Or Cloudy filtrate tank 10CE05 level LIC9050 is Low-LowWhile pump 10PPC09 is fed from tank 10CE05 (through manual valve MV-9053)

Then Periodic water pump 10PPC09 is stopped.

If Clear filtrate tank 10CE06 level LIS9055 is LowWhile pump 10PPC09 is fed from tank 10CE06 (through manual valve MV-9024)

Or Cloudy filtrate tank 10CE05 level LIC9050 is LowWhile pump 10PPC09 is fed from tank 10CE05 (through manual valve MV-9053)

Then Inhibit start of Periodic water pump 10PPC09

198- LOOP 2 PERIODIC WATER PUMP 10PPC09 TO SLAVE VALVE AV-9090

If Periodic water pump 10PPC09 is not runningThen On/Off slave valve AV-9090 is forced closed

If Periodic water pump 10PPC09 is runningThen With on delay T=5s, On/Off slave valve AV-9090 in Auto opens (air ex-


199- INTERLOCKS TO TRANSFER WATER PUMP 10PPC10

If Clear filtrate tank 10CE06 level LIS9055 is Low-LowThen Transfer water pump 10PPC10 is stopped.

If Clear filtrate tank 10CE06 level LIS9055 is LowThen Inhibit start of Transfer water pump 10PPC10



200- INTERLOCKS TO RECIRCULATION CHEST DILUTION PUMP 10PPC13

If Cloudy filtrate tank 10CE05 level LIC9050 is Low-LowThen Dilution water pump 10PPC13 is stopped.

If Cloudy filtrate tank 10CE05 level LIC9050 is LowThen Inhibit start of Dilution water pump 10PPC13

201- DILUTION PUMP 10PPC13 TO ON/OFF VALVES AV-6155 & AV-6160

If Dilution water pump 10PPC13 is not runningThen On/Off valves AV-6155 & AV-6160 are forced closed

If Dilution water pump 10PPC13 is not runningThen With on delay T=5s, On/Off valves AV-6155 & AV-6160 in Auto open

202- (RESERVE)

ALARMS

203- SEALING WATER

If Loop 2 Disc Filter & water distribution area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


204- COMPRESSED AIR

If Loop 2 Disc Filter & water distribution area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


205- (RESERVE)



1.54 OPERATION

1.54.1 Start-up

Loop 2 water distribution is the first area to start in Loop 2, in order to store ne-cessary water for all equipment start-up and dilution.



Low).- Loop 3 filtrate tank 13CE08 level LIC13005 is not Low


If water tanks are empty (for example on first start-up):

Open On/Off water valve AV-9085 for filling of Clear filtrate tank 10CE06 with Loop 3 filtrates provided by pump 13PPC11.

Cloudy filtrate tank 10CE05 in cascade is filled through overflow.

As soon as water tank levels are up to Low level, all connected water pumps can start if required by the sub-systems or in manual by operator.

1.54.1.2 Disc Filter 10FDQ04 start

Basic conditions:- Clear Filtrate tank 10CE06 level LIS9055 is not Low.- Downstream Heating screw 14VIT01 is running.

For start-up of sequence, the clear filtrate seal chamber should be filled with either clear filtrate or fresh water up to the maximum level of this chamber so that overflow occurs into the clear filtrate tank.

Start Loop 1 Disc Filter Repulping screw 10FDQ04b.

Start Disc Filter Shower Pump 10PPC07 and open its delivery valve AV-9035.

Start Oscillating shower drive 10FDQ04c.

Start Loop 1 Disc Filter Main Drive 10FDQ04.

When running status obtained for both, set Disc Filter status to READY.



1.54.1.3 Production

The process bloc starts in production with the Post-flotation bloc (Once the stock is bled downstream of the constant level box 08CP02 via control valve FCV-8010).

Feed pump 10PPC03 is allowed to start with Disc Filter READY status.

When feed pump 10PPC03 is started:Put the Disc Filter trough level controller LIC9020 in AUTO Mode.

1.54.2 Operation


Monitoring of HP shower water pressure. Monitoring of consistencies (Water and stock). Monitoring of operating vacuum



1.54.3 Shutdown


The process bloc stops in production with the Post-flotation bloc by closing of the control valve FCV-8010 outlet of the constant level box 08CP02.

Loop 2 Disc Filter stops in production with stop of feed pump 10PPC03.

1.54.3.2 Disc Filter 10FDQ04 stop

Reset Disc Filter status to Not READY

Stop the disc filter main motor after time delay of 10 minutes to ensure that as much of fiber is recovered as possible from the liquid in the trough.

Stop Loop 2 Disc Filter Oscillating shower drive 10FDQ04c.

Stop Disc Filter Shower Pump 10PPC07 and close its delivery valve AV-9035.

Stop the stock repulper screw drive after time delay of 5 minutes, to ensure that stock does not remain in the screw trough during stoppage.

CAUTION!It would be preferable to operate the Disc Filter system for 5-10 minutes with just showers water for internal cleaning prior to any medium duration stoppage (up to 4 hours).

For stoppages exceeding 4 hours, it would be preferable to clean the internal sys-tem and have the trough drained fully. The contents of the trough should be drained very slowly and gradually to avoid physical damage to the internal com-ponents of the trough and rotor due to build-up of vacuum caused by excessively rapid draining (siphon effect). Use of wire cleaning showers to clean the filter fab-rics is recommended. The inside of the hood and the showers pipes should also be cleaned with water hose under pressure.


All Filtrate pumps are stopped when no more required by any depending sub-sys-tems (Loop 1 & Loop 2 dilutions, Micro-flotation feed if required through pump 10PPC10).



PROCESS DESCRIPTION


PRINTING - WRITING

REDUCTIVE BLEACHING

REDUCTIVE BLEACHINGPage 194/264


13 REDUCTIVE BLEACHING

1.55 DESCRIPTION

1.55.1 Reductive bleaching itemization

Heating Screw ...............................................................................14VIT01

Stand Pipe ...............................................................................14CE02

MC pump ............................................................................14PMC03

Reactive tube 1 ...........................................................................14BLT07A

Reactive tube 2 ...........................................................................14BLT07B

1.55.2 Heating screw

The heating screw is a simple system, operating at fixed speed.It is composed by: -A metallic body with steam injectors.-A conveying screw

The Heating screw is a simple system, operating at fixed speed, with steam injec-tion into the pulp agitated & transported by the screw.

1.55.3 MC Pump basics

The MC-Pump system consists of

- A stand pipe for Pump feeding with thick stock.

- The MC Pump itself, with a special pulp impeller that fluidises the pulp.




1.55.4 Reductive bleaching description

1.55.4.1 Heating screw

The Heating screw is a simple system, operating at fixed speed, with steam injec-tion into the pulp agitated & transported by the screw.

It receives the 10-12% accept pulp from Loop 2 Disc Filter 10FDQ04.

Heated pulp temperature is measured and controlled by TIC15005 by actuating valve TCV-15005 on 3 Bars g Steam, to achieve a constant temperature of pulp at the outlet of Heating Screw.

Heating temperature set-point (i.e. steam quantity to be injected) must be adap-ted according to type of chemicals used and to pulp required temperature during reaction in order to reach adequate conditions for the best reductive bleaching ef-ficiency.

A minimum pulp flow is required to enable steam injection by temperature con-troller TIC15005, to avoid excessive steam exhaust. MC-Pump level controller LICS15020 output is used for this signal: if level controller output is less than 10%, the steam valve TCV-15005 is forced closed.

Heating Screw 14VIT01 rotation is monitored by speed switch SS15010 allowing detecting an eventual incident in this transfer screw.

Heated pulp falls by gravity from the Heating Screw to the MC Pump stand-pipe 14CE02.

1.55.4.2 MC pump and reactive tubes

Note: The following description for MC pump operation & associated regulations correspond with a Sulzer pump type.This paragraph is to be adapted and/or corrected in case of another supplier.

Dilution water is injected to the stand pipe base through control valve LCV-15020 and to the top part with hand regulated command HIC15015.



In addition, LICS15020 controls valves LCV-15020 & HCV-15015 dilution valves to Stand-pipe, opening the level dilution valves when the level rises.

In Manual mode, Top dilution valve HCV-15015 and bottom dilution valve LCV-15020 can be opened at any time.

In Auto mode, Top dilution valve HCV-15015 is opened at operator defined open-ing set-point + controlled value related to deviation of LICS15020 from set-point.



Bottom dilution valve LCV-15020 is normally closed, and opens to operator set value when LICS15020 measure is greater than 30% above set-point and MC Pump is running.

The MC-Pump 14PMC03 act as a Chemical mixer for the required chemicals, dosed from Chemical Distribution system proportionally to the pulp tonnage.

Reductive Bleaching agent can be injected into the base of the stand pipe near suction flange of the MC pump or through the chemicals injection connection on the MC pump casing.The proper dosing proportional factor is checked by observation of the pH value measured off-line on pulp sampled from MC-Pump delivery or with final pH meas-urement AIR15070 at Storage Tower 14CPA04 outlet.

The MC Pump 14PMC03 pumps the stock forward to: Reactive tubes 14BLT07A and 14BLT07B feeding downstream pro-

cess (dispersing system). Or Recirculation chest 07CPA11.

The pulp bleaching proceeds at medium consistency and reactive tubes are doubled (in parallel) in order to get a sufficient residence time of the pulp to achieve a proper bleaching efficiency.

1.55.4.3 Recirculation chest 07CPA11

During transitory phase (like on start-up or during an eventual incident in down-stream process), a recirculation line from MC pump 14PMC03 outlet (through On/Off valve AV-9015 open and with On/Off valve AV-15035 closed) allows recir-culation of Loop 2 Accept stock back to intermediate chest 07CPA11.

This pulp transferred to chest 07CPA01 is diluted in line with filtrates from pump 10PPC13 and through On/Off valve AV-6155 in order to decrease consistency from 10 to 4-5%.

When operator activates loop 2 accept stock recirculation to Dump chest, a se-quence automatically:

Starts filtrate pump 10PPC13 Opens filtrate valve AV-6155 Opens by-pass valve AV-9105 and closes opposite valve AV-15035 Sets in Auto mode level controller LIC6007 Enables start of agitator 07AG12 and extraction pump 07PPC13 (mo-

tors start depend also on interlocks).




- Nominal MC Pump delivery 360 BDT/d at 8-12%


MC Pump control loops to be checked with corresponding supplier.



TIC 15005Temperature control of pulp in Heating screw 14VIT01

0-150°C

SS 15010Heating screw 14VIT01 rotation alarm Speed switch

* Digital alarm

HIC 15015Manual control valve of dilution water to top of Stand Pipe 14CE02

0-100%


5% 15% 85% 95% 0-100%

SIC 15025MC Pump 14PMC03 motor speed Con-trol

0-100%




206- INTERLOCK TO HEATING SCREW 14VIT01

If MC pump 14PMC03 is not running Or MC pump Stand Pipe level LICS15020 is High-High for 15 s

Then Heating screw 14VIT01 is stopped

207- ROTATION SWITCH SS15010 TO HEATING SCREW 14VIT01

If Rotation switch SS15010 is alarm zero rotationAnd Heating screw 14VIT01 is running with start up override T=5s

Then Heating screw 14VIT01 is stopped

208- INTERLOCKS TO STEAM HEATING TIC15005

If Heating Screw 14VIT01 is not running (on-delay T=20s)Or Loop 2 Disc Filter feed pump 10PPC03 is not running (on-delay T=30s)Or MC pump 14PMC03 is not running (on-delay T=20s)Or MC pump Stand Pipe level LICS15020 is High-High for 15 sOr MC pump Stand Pipe level LICS15020 output is less than 10% for T=5s

(on-delay T=20s)Or TIC15005 is alarm High-High for T=10s (on-delay T=20s)

Then Temperature controller TIC15005 is disabled with valve TCV-15005 forced closed

Interlock is released after the on-delay T=20s of healthy status & enables control-ler.

209- REDUCTIVE CHEMICALS DOSAGE

If MC pump 14PMC03 is not runningOr MC pump Stand Pipe level LICS15020 is Low-LowOr MC pump Stand Pipe level LICS15020 output is less than 10% for T=5s

(on-delay T=20s)

Then Chemicals dosage to MC Pump is forced closed(Action to be identified, chemicals study is out of KADANT scope)



210- STAND PIPE INTERLOCK TO MC PUMP 14PMC03

If MC pump Stand Pipe level LICS15020 is Low-Low for 30s


211- DISPERSING SYSTEM INTERLOCK TO MC PUMP 14PMC03

While Pulp Recirculation to chest 07CPA11 is not activated, meaning by-pass On/Off valve AV-9105 closed and opposite On/Off valve AV-15035 open.

If Storage Tower 12CPA03 level LIS11045 is alarm High-High for 30sOr Screw Press Dispersing system is not running when required (On/Off

valves AV-10115 & AV-10120 open, On/Off valves AV-10125 & AV-10130 closed)

Or MC pump Stand Pipe level LICS15020 is Low-Low for 30s




Then Level controller LICS15020 is disabledAnd Control valve HCV-15015 if in Auto is closedAnd Control valve LCV-15020 if in Auto is closed



And Output to valve LCV-15020 is enabled(HCV-15015 output is enabled on motor start-order)

213- LOOP 3 DILUTION WATER INTERLOCK TO MC PUMP WATER CONTROL VALVES

If Loop 3 dilution pump 13PPC09 is not runningThen Control valves HCV-15015 and LCV-15020 are forced closed.

If Loop 3 dilution pump 13PPC09 is not runningAnd MC Pump 14PMC03 is running




214- (RESERVE)

215- (RESERVE)

ALARMS

216- SEALING WATER

If Reductive Bleaching area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


217- STORAGE TOWER 12CPA03 LEVEL LIS11045

If Storage tower 12CPA03 level controller LIS11045 is High


218- COMPRESSED AIR

If Reductive Bleaching area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


219- (RESERVE)



1.59 OPERATION

1.59.1 Start-up

Reductive Bleaching area is started after Downstream Dispersing system or pulp will have to be recirculated to chest 07CPA11.

1.59.1.1 Start of the Loop

Basic conditions:- Storage tower 12CPA03 level LIS11045 is not High alarm- Sealing water main line is under pressure and Flow switch FSA20135 is not


Low).- Steam network under pressure- Loop 3 clarified water tank 13CE08 level LIC13005 is not Low.- Screw Press in downstream dispersing system (if used) is running- Chemicals ready

If not already running, start Loop 3 dilution pump 13PPC09.

Start MC-Pump 14PMC03 (start order with Dispersion System sequence if used – See § 1.64.1.1 – Page 220).

Start Heating Screw 14VIT01

All items of sub-system - in Auto mode - start according to interlocks defined above:- Dilution to Stand-pipe opens by interlock on MC Pump start-order; - Controller LICS15020 & SIC15025 are enabled when MC-Pump is running;

1.59.1.2 Production

The process bloc starts in production start of feed pump 10PPC03.Then Heating screw is fed with pulp from Loop 2 Disc Filter.

Pulp heating controller TIC15005 is enabled on delay after stock feed pump 10PPC03 start.

1.59.2 Operation

To be monitored during the operation of the installation: Monitoring of Steam pressure Monitoring of Chemicals feeding



1.59.3 Shutdown

Normal stop operation will lead to stop Red Bleaching MC-Pump after stopping Loop 2 Disc Filter area.It is strongly advised against stopping MC-Pump while Heating screw is running - except in case of emergency.

The process bloc stops in production with closing of the control valve FCV-8010 outlet of the constant level box 08CP02 and with pump 10PPC03 motor stop.

Stop Heating Screw 14VIT01

Stop MC-Pump 14PMC03 (start order with Dispersion System sequence if used – See § 1.64.3.2 – Page 222).All actuators revert to required position through interlock action. The dilution valves may be opened manually thereafter for flushing if required.



PROCESS DESCRIPTION


PRINTING - WRITING

LOOP 2 DISPERSING SYSTEM

LOOP 2 DISPERSING SYSTEMPage 204/264


14 LOOP 2 DISPERSING SYSTEM

1.60 DESCRIPTION


Screw press ...............................................................................11KR01

Plug screw ...............................................................................11KR02

Shredder ...............................................................................11KR03

Preheater ...............................................................................11KR04

Infeeder ...............................................................................11KR05

Disperser ...............................................................................11KR06

Storage tower .............................................................................12CPA03

Storage tower agitator ...............................................................................12AG04

Storage tower extraction pump................................................................................12PPC05

1.60.2 Dispersing system

Dispersing system consists of succession of the following equipment:

- Screw press- Plug Screw- Shredder- Preheater- Infeeder- Disperser





1.60.3.1 Dispersing system

Note: The following description for Dispersing system must be checked and com-pleted by supplier.

Screw Press 11KR01

Screw-Press 11KR01 thickens the 10-12% pulp (from Reductive Bleaching via MC pump 14PMC03) to 30-35% consistency required for Dispersing.

By-pass lines on each reactive tube outlet (through On/Off valve AV-10130 for tube 14BLT07a and AV-10125 for tube 14BLT07b) can send pulp directly to downstream storage tower 12CPA03.By this way, deinking line can operate without this dispersion step.

Screw press mechanism is equipped with a packing box and monitoring alarms (FS10095 and PS10100) helping to protect internal elements.

Screw press drive is equipped with a variable speed motor controlled by SIC10010 and screw rotation is monitored by speed switch SSL10011 allowing detecting an eventual incident.

The filtrates extracted from the Screw press flow by gravity to Loop 2 Cloudy Fil-trate Tank 10CE05.

The 30-35% consistency stock accepted from the Screw press feeds directly Plug Screw 11KR02.

Reductive chemicals can be injected in Screw Press outlet chute if required for a best pulp bleaching efficiency.

Screw press speed control & Torque controller:

Inputs:Process value: Taken from the frequency converter and scaled to Nm.Set point: Operator controlled parameter.SP Ramp: 5 Nm per second. Auto/Manual: Default “Auto”. PV filter: 4s. Filter to flatten the process value signal.

To be applied either in frequency converter or in control system.Maximum output: This is to be set at 100%. Minimum output: To be set at 0%. Maximum SP: 50%. Minimum SP: 0%. HHAL: 70%.HAL: 60%.



Output:Output from controller forwarded frequency converter speed reference input.

Function:Process value < Set point makes output decrease.Process value > Set point makes output increase.

Plug Screw 11KR02

Plug screw transfers Screw Press outlet pulp to Shredder 11KR03.

Plug screw rotation is monitored by speed switch SSL10012 allowing detecting an eventual incident.

Temperature there is measured by TIC10015.

Shredder 11KR03

Shredder 11KR03 transfers pulp from Plug Screw to Preheater 11KR04.

Shredder rotation is monitored by speed switch SSL10013 allowing detecting an eventual incident.

Shredder mechanism is equipped with a packing box and monitoring alarms (FS10085 and PS10090) helping to protect internal elements.

Part of Steam required from Preheater heating controller TIC10020 can be injec-ted there.

Preheater 11KR04

It receives the 30-35% accept pulp from upstream shredder.

Preheater mechanism is equipped with 2 packing boxes and monitoring alarms (FS10085 and PS10090) helping to protect internal elements.

Preheater 11KR04 rotation is monitored by speed switch SSL10014 allowing de-tecting an eventual incident in this transfer screw.

Temperature & Steam pressure control

Heated pulp temperature is measured and controlled by TIC10020 and PIC10020 by actuating valve PCV-10020 on Steam supply pipe, to achieve a constant tem-perature of pulp at the outlet of Preheater.Steam injection is adjustable through manual valves on each steam pipe connec-ted to shredder 11KR03 and Preheater 11KR04.

Heating temperature set-point (i.e. steam quantity to be injected) must be adap-ted according to type of chemicals used and to pulp required temperature during



reaction in order to reach adequate conditions for the best reductive bleaching ef-ficiency.

Interlocks: If emergency stop is activated (broken circuit), the valve is forced

closed. If the pulp feed is shut off, the steam valve is forced closed. If the temp. transmitter on the plug screw cone indicates high temp, i.e.

approx. 10°C above normal pulp temp), the valve is forced closed.

Operation: Pressure controller PIC10020 is the primary controller. Temperature controller TIC10020 is the secondary controller. Pressure controller operates the valve by its output value. Temp. controller output controls the set point value of the pressure con-

troller as a cascade control. Pressure set point range: 0-1,5bar. Temp. set point range: 90-120ºC.

Auto: Temp. Process Value < Set Point makes steam pressure Set Point big-

ger. Pressure Process Value < Set Point makes valve output increase. Temp. Process Value > Set Point makes steam pressure Set Point

smaller. Pressure Process Value > Set Point makes valve output decrease.

Infeeder 11KR05

Infeeder 11KR05 transfers pulp from Preheater to Disperser 11KR06.

Infeeder screw rotation is monitored by speed switch SSL10016 allowing detect-ing an eventual incident.

Infeeder mechanism is equipped with a packing box and monitoring alarms (FS10085 and PS10090) helping to protect internal elements.

Disperser 11KR06

The pulp introduced into the Disperser is subjected to shear forces between stator & rotor.

Disperser mechanism is equipped with a packing box and monitoring alarms (FS10065 and PS10070) helping to protect internal elements.

Lubricating system for Disperser 11KR06 drive is equipped with an oil cooler monitored by alarms FS10075 and PS100870.

The thick stock in Disperser is diluted in outlet zone in concordance with set-point consistency of controller NIC10045, acting on control valve NCV-10045 on Loop 3 filtrates provided through pump 13PPC18.



Water dilution and Disperser stock outlet pressures are controlled respectively through PIC10055 and PIC10060 with their associated control valves on corres-ponding pipe.

Disperser 10KR06 outlet stock falls directly in storage tower 12CPA03.

Backpressure control

Interlocks: Forced open 100% if steam control valve is closed. Valve output must be min. limited (approx. 20-30%). Set point range: 1.5-2.0 bar

Operation (auto): Backpressure Process Value < Set Point makes valve output decrease. Backpressure Process Value > Set Point makes valve output increase.

Consistency control NIC10045 (after Disperser)

Interlocks: Control valve forced closed when Disperser motor is not running. Should have a mini limit of 20% when in automatic mode.

Operation: Set point range: 9-11%

Auto: Consistency Process Value < Set Point makes valve output decrease. Consistency process Value > Set Point makes valve output increase.

Disc gap control (adjustment of operating gap from computer)

Interlocks: Gap set point to be limited to 0,10mm minimum gap. Gap set point to 1,20mm if steam control valve closes.

Disc gap adjustment from computer shall not work when: Switch for disc gap control is in local position on the Panel. Hydraul/Lubepump is not running. Discs is in rear position.

Disc gap set to rear position (solenoid MV1 energized) if: Emergency stop or service switch is activated (broken circuit - valid only

for computer). Disc gap - backwards (panel/computer) is selected.



Operation: The control loop is fed with an analog input (4-20 mA=0-10 mm). The

controller sets one of two digital outputs that increases or decreases the disc gap. (Energizing two relays in local panel).

Auto: Disc gap process value < set point gives a constant signal at increase -

output. Disc gap process value > set point gives a constant signal at decrease -

output.

NOTE! A span of ±0.03 mm should be used to avoid that the controller is con-

tinuously searching for the right gap. If the respond from the process value into the controller is too slow, a

recommendation is to give pulses of 0,5 seconds to the output, when gap reaches ±0.20 mm from set point.

1.60.3.2 Storage tower 12CPA03

The thick stock falls from Disperser into Storage tower 12CPA03 at consistency 5 to 10% according to controller NIC10045 set-point.

Bleaching tower 12CPA03 level is measured by LIS11045.

High Level LIS11045 is one of the main levels on the line, to be monitored by op-erator to control the production & stability on loop 2 by acting on Loop 2 produc-tion set-point (through flow controller FIC8010 regulating stock feed to Post-Flota-tion area) or on Loop 3 production set-point (through flow controller FIC12005 regulating stock feed to Washing).

Modification of Loop 2 production set-point will have also a repercussion on Bleaching tower 07CPA01 level and will lead operator to adjust Loop 1 set-point (through Pre-Flotation feed controller FIC3020).

The Storage tower must have a minimum level of filtrates or stock prior to feeding thick stock - to prevent block agitator or extracting system. This requires pre-filling on filtrates prior to start the line. Operator does this filling manually from DCS.

Storage tower 12CPA03 is equipped with a horizontal agitator 12AG04.

Pump 12PPC05 extracts the stock from Storage tower to downstream process: Through On/Off valve AV-11110 to Washing system if required by Loop

3 feed controller FIC12005. And / Or through On/Off valve AV-11105 directly to Final Storage tower

14CPA04 if required by Loop 3 feed controller FIC15095.(See more detailed Description in § 1.65.4.1 - Washing area feed and by-pass – Page 228).



Tower extracted pulp consistency is controlled by NRC11050 and adjusted with addition of Loop 3 Filtrates (from pump 13PPC18) in tower 12CPA03.Most part of this dilution flow is directed (via control valve QCV-11055) to Tower 12CPA03 bottom diluting zone in order to reduce consistency to around approx. 5%.Remaining dilution water flow is directed (via control valve NCV-11050) to suction of pump 12PPC05 where consistency reaches more finely 4-4,5%.Controller QC11055 operates as a proportional ratio in order to adjust associated valves (QCV-11055 and NCV-11050) opening values and then the sharing of total dilution flows (usually 70% of total flow through valve QCV-11055 and 30% through NCV-11050).

Extraction pump 12PPC05 outlet pressure is controlled via PIC11060 and adjus-ted with control valve PCV-11060 or On/Off valve AV-11100 on 2 parallel recircu-lation pipes back to Storage tower bottom.- The smallest diameter valve PCV-11060 will be enabled with controller

PIC11060 during normal operation (when pressure recirculation flow is lim-ited).

- The biggest diameter On/Off valve AV-11100 will be used during transitory phases (like start-up) requiring a bigger pressure recirculation (even a total re-circulation).

During start-up, the recirculation at the bottom of the tower is turned on in order to reach an appropriate consistency before feeding downstream chest 12CPA06:

On/Off valve AV-11100 opens. Control valve LCV11070 on transfer pipe is forced closed.

When desired consistency is obtained; and stabilized, the full recirculation is shut down:

On/Off valve AV-11100 closes Pump 12PPC05 outlet pressure is controlled by PIC11060 in AUTO

mode and through control valve PCV-11060. Pulp is sent downstream.

Brightness of extracted pulp from Tower 12CPA03 is measured by transmitter AIR11065 and displayed/recorded.




Dispersing System:

- Outlet Production of Dispersing System 350 BDT/d at 5-10%

Refer to supplier for system operating capacity of each equipment.


Note: The following control loops must be checked and completed by supplier.



SSL 10011Screw Press 11KR01 rotation alarm Speed switch

* Digital alarm

SIC 10010Screw Press 11KR01 motor speed Con-trol

0-100%

FS 10095Flow alarm switch on system for Screw Press 11KR01 packing box

Digital alarm

PS 10100Pressure alarm switch on system for Screw Press 11KR01 packing box

Digital alarm

SSL 10012Plug Screw 11KR02 rotation alarm Speed switch

* Digital alarm

TIC 10015Temperature indication inside Plug Screw 11KR02

SSL 10013Shredder 11KR03 rotation alarm Speed switch

* Digital alarm

FS 10085Flow alarm switch on system for packing boxes of Infeeder, Preheater (x2) and Shredder

Digital alarm

PS 10090Pressure alarm switch on system for packing boxes of Infeeder, Preheater (x2) and Shredder

Digital alarm

TIC 10020Temperature control inside Preheater 11KR04

PIC 10020Pressure control of steam injection inside Preheater 11KR04

SSL 10014Preheater 11KR04 rotation alarm Speed switch

* Digital alarm

…/…





SSL 10016Infeeder 11KR05 rotation alarm Speed switch

* Digital alarm

FS 10075Flow alarm switch on system for Dis-perser 11KR06 oil cooler

Digital alarm

PS 10080Pressure alarm switch on system for Dis-perser 11KR06 oil cooler

Digital alarm

FS 10065Flow alarm switch on system for Dis-perser 11KR06 packing box

Digital alarm

PS 10070Pressure alarm switch on system for Dis-perser 11KR06 packing box

Digital alarm

NIC 10045Consistency control of stock outlet of Dis-perser 11KR06

PIC 10055Pressure control of dilution water to Dis-perser 11KR06 outlet

PIC 10060Pressure control of stock outlet of Dis-perser 11KR06

LIS 11045 Storage tower 12CPA03 level control 5% 15% 85% 95% 0-200 m³

NRC 11050Storage tower 12CPA03 extracted pulp consistency control

0 to 5%

QC 11055Ratio repartition for Storage tower 12CPA03 pulp dilution water flow

0-100%

PIC 11060Storage tower 12CPA03 extracted pulp pressure control

0–4 Bars

AIR 11065Brightness indication of Storage tower 12CPA03 extracted pulp




1.63.1 Dispersing system

Dispersing system interlocks and alarms to be corrected and/or corrected with corresponding supplier.

220- INTERLOCKS TO DISPERSER 11KR06 HYDRAUL / LUBEPUMP

If OFF (panel/computer) is activated (broken circuit).Or Disperser 11KR06 is not running within 240 sec.Or Disperser 11KR06 stops. Time delay 240 sec.

Then Disperser 11KR06 Hydraul/Lubepump stops.

221- INTERLOCKS TO DISPERSER 11KR06

If OFF (panel/computer) is activated (broken circuit).Or Emergency stop or service switch is activated (broken circuit).Or Hydraulic pressure switch is not activated (low pressure = broken circuit,

hardwired to motor control cabinet).Or Lubrication oil flow switches are not activated (low flow = broken circuit,

hardwired to motor control cabinet).Or Disperser 11KR06 Hydraul/Lubepump is not runningOr Sealing & oil cooling water On/Off valve AV-10105 is not open.Or Storage tower 12CPA03 level is High-High for T=45s.Or Oxidative bleaching tower 12CPA03 level is Low-Low.

Then Disperser 11KR06 stops.

222- INTERLOCKS TO INFEEDER 11KR05

If OFF (computer) is activated (broken circuit).Or Emergency stop or service switch is activated (broken circuit).Or Slow speed limit switch SS10016 is not activated (low speed = broken

circuit).Or Disperser 11KR06 is not runningOr Dilution water pump 13PPC18 is not runningOr Control valve PCV-10055 on dilution water pipe is closedOr Pressure switch for dilution water is not activated, i.e. pressure is below

2 bars for more than 5 sec. (low pressure = broken circuit).

Then Infeeder 11KR05 stops.



223- INTERLOCKS TO PREHEATER 11KR04


circuit).Or Infeeder 11KR05 is not running

Then Preheater 11KR04 stops.

224- INTERLOCKS TO TEMPERATURE & STEAM PRESSURE CONTROLLERS

If Emergency stop or service switch is activated (broken circuit).Or Screw Press 11KR01 torque controller is not in Auto mode.Or Feed pump 14PMC03 is not running (with on-delay T=120s)Or Temperature TIC10020 is alarm High-High (on-delay T=20s)Or Temperature TIC10015 on the Plug Screw 11KR02 indicates High Tem-

perature (i.e. approx. 10°C above normal pulp temperature)

Then Temperature (TIC10020) & Steam pressure (PIC10020) controllers are disabled with valve PCV-10020 forced closed

Note: If TIC10020 is in Auto and the interlocking conditions are set to healthy, the controller is enabled after specified on-delays. In Manual, the controller remains at closed value.

225- INTERLOCKS TO SHREDDER 11KR03


circuit).Or Preheater 11KR04 is not running

Then Shredder 11KR03 stops.

226- INTERLOCKS TO PLUG SCREW 11KR02


circuit).Or Shredder 11KR03 is not running

Then Plug Screw 11KR02 stops.



227- INTERLOCKS TO SCREW PRESS 11KR01


circuit).Or Plug Screw 11KR02 is not running

Then Screw Press 11KR01 stops.

228- INTERLOCKS TO SCREW PRESS 11KR01 COUNTER PRESSURE CONE

If Screw Press 11KR01 is not running.Or Open (computer) is selected (broken circuit).Or Pulp feed pump 14PMC03 is not running on delay T=30s.Or Screw Press speed Torque controller is on Alarm High

Then Counter pressure cone in Screw Press opens (solenoid valve ener-gized).

229- INTERLOCKS TO SEALING AND COOLING WATER VALVE

If Hydraul/Lubepump is not running.Then Sealing water and Cooling water On/Off valve closes

If Hydraul/Lubepump is running.Then Sealing water and Cooling water On/Off valve opens

230- INTERLOCKS TO DISC GAP

If Disc gap – backwards (panel/computer) is selectedThen Disc gap set to rear position

If Hydraul/Lubepump is running.And Selector switch (local panel) for disc gap control is set to remote mode

Then Disc gap can be set to rear or operating position (valid for computer)

If Steam control valve PCV-10020 closesThen Disc gap set-point to 1,20mm

If Steam control valve PCV-10020 closesThen Disc gap set-point to 1,20mm



231- INTERLOCKS TO DRAINAGE VALVE

If Dilution water pump 13PPC18 is not running.Then Drainage On/Off valve opens

If Dilution water pump 13PPC18 is running.Then Drainage On/Off valve closes

232- INTERLOCKS TO OUTLET CONSISTENCY CONTROL NIC10045

If Disperser 11KR06 is not runningOr Loop 3 dilution pump 13PPC18 is not running

Then Controllers QC11055 and NRC11050 are disabled with control valves QCV-11055 and NCV-11050 forced closed.

233- SCREW PRESS INTERLOCK TO CHEMICAL DOSAGE

If Screw Press 11KR01 is not running (with on-delay T=30s)Or Feed pump 14PMC03 is not running (with on-delay T=30s)

Then Chemical supply to Dispersing System is DISABLED (to Chemical dosage pumps).

The On-delay T=30s means that chemical supply will remain forbidden T=30s after the interlock has been released.

234- (RESERVE)

235- (RESERVE)

1.63.2 Storage tower 12CPA03

236- STORAGE TOWER LEVEL LIS11045 TO AGITATOR 12AG04

If Storage tower 12CPA03 level LIS11045 is LowThen Stop Agitator 12AG04

If Storage tower 12CPA03 level LIS11045 is LowThen Inhibit Start Agitator 12AG04



If Storage tower 12CPA03 level LIS11045 is not LowAnd Agitator 12AG04 is DCS Auto mode


237- LEVEL LIS11045 HIGH_HIGH INTERLOCK TO DILUTION VALVES

If Storage tower 12CPA03 level LIS11045 is High-High

Then Controllers QC11055 and NRC11050 are disabled with control valves QCV-11055 and NCV-11050 forced closed

Note: this interlock is designed to prevent adding dilution filtrates to a full tower.

238- INTERLOCKS TO TOWER EXTRACTION PUMP 12PPC05

If Storage tower 12CPA03 level LIS11045 is LowOr Agitator 12AG04 is stopped

Then Pump 12PPC05 is stopped.

If Storage tower 12CPA03 level LIS11045 is LowThen Inhibit start of pump 12PPC05.

(This interlock prevents tripping the pump motor on start-up by extracting pulp that is not properly agitated & homogenized in the bottom of the Tower).

239- TOWER EXTRACTION PUMP 12PPC05 TO REGULATIONS ON DELIVERY PIPES

If Tower extraction pump 12PPC05 is not running

Then Chest 12CPA06 feed control valve LCV-11070 is forced closed.And Control valve FCV-15095 on by-pass line is forced closed.

240- INTERLOCKS TO CONSISTENCY CONTROLS NRC11050 & QC11055

If Tower extraction pump 12PPC05 is not runningOr Loop 3 dilution pump 13PPC18 is not running

Then Controllers QC11055 and NRC11050 are disabled with control valves QCV-11055 and NCV-11050 forced closed.



241- INTERLOCKS TO PRESSURE CONTROL PIC11060


Then Controller PIC11060 is disabled with control valve PCV-11060 and On/Off valve AV-11100 forced closed.

242- (RESERVE)

ALARMS

243- SEALING WATER

If Loop 2 dispersing system area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


244- COMPRESSED AIR

If Loop 2 dispersing system area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


245- BLEACHING TOWER 12CPA03 LEVEL LIS11045

If Bleaching tower 12CPA03 level controller LIS11045 is High


246- (RESERVE)



1.64 OPERATION

Note: This paragraph is based on supplier information.(To be checked and completed if necessary).

1.64.1 Start-up

The Loop 2 Dispersing System is the first pulp system started in Loop 2.It starts only if the Storage Tower 12CPA03 level is not High AND not Low-Low.



Low).- Steam network under pressure- Chemicals ready- Loop 3 filtrate tank 13CE08 Level LIC13005 is not Low.- Storage Tower 12CPA03 level LIS11045 is not High AND not Low-Low- Selection of operation with Dispersing System. Position of MC pump

14PMC03 outlet valves: Valve AV-9105 closed (to recirculation chest 07CPA11 Screw Press By-pass valves AV-10125 & AV-10130 closed Valves AV-15035, AV-15040, AV-15045, AV-10115 & AV-10120 open

Note: If Storage Tower 12CPA03 level is Low, operator needs to pre-fill the Tower with Loop 3 filtrates from pump 13PPC18.


The system is started by sequentially starting all elements from downstream to upstream.

Disperser 11KR06 Hydraul / Lubepump ON.

Backpressure control valve PCV-10060 100% open

Disperser discs in opening position (solenoid valve de-energized).Time delay 10 seconds.

Check that Discgap is > 1,20mm (If Less send Increase signal)

Wait until gap is > 1,20mm (When bigger stop Increase signal)

Disperser discs in rear position (solenoid valve energized).

Receive signal from back out limit switchTime delay 10 seconds.



Disperser 11KR06 main motor on.Time delay 10 seconds.

If not already running, start Loop 3 filtrates pump 13PPC18.

Consistency transmitter activated and controller NIC10045 in Auto mode.

Disperser discs in operating position (solenoid valve de-energized).Time delay 5 seconds.

Infeeder 11KR05 ONTime delay 3 seconds.

Preheater 11KR04 ONTime delay 3 seconds.

Shredder 11KR03 ONTime delay 3 seconds.

Plug Screw 11KR02 ONTime delay 3 seconds.

Screw press 11KR01 ON

Torque controller to Manual and 80% output.Time delay 10 seconds.

Screw Press counter pressure cone solenoid valve de-energized.

Start feed MC pump 14PMC03.Time delay 120 seconds.

Torque controller to automatic and standard set-point.

Steam temperature controller in Auto mode (if required by bleaching sequences).

Backpressure controller in Auto mode.

Wait until the pulp temperature is > 80°C (if required by bleaching sequences).

Decrease the disc gap within the range 0,10 – 0,50 mm.

The system is running.



1.64.1.2 Production

The whole Loop 2 starts in production with Post-Flotation area: with the opening of valve FCV-8010 at the outlet of the constant level box 08CP02.

The whole LOOP2 line is then started, and when stock arrives to Storage Tower 12CPA03.

Chemical dosage is allowed through interlocks.


Monitoring of stock consistencies. Monitoring of Steam pressure Monitoring of drive motors load. Monitoring of Bleaching efficiency Checking of Storage Tower 12CPA03 (one of the main parameters in

the line).

1.64.3 Shutdown


Loop 2 DIP line stops in production with closing of the Post-Flotation feed control valve FCV-8010 at outlet of the constant level box 08CP02.

Provided there is no pulp flow to the Loop 2 Disc Filter, Dispersing system sub-system can be stopped.


Dispersing system is stopped after Loop 2 Disc Filter area.

Send increase the Disc Gap signal until Disc Gap is > 1,20mm.

Stop feed MC pump 14PMC03.

Energize solenoid valve of Screw Press counter pressure cone

Wait approx. T=180s (The whole is emptied from pulp)

Discs movers to rear position (solenoid valve energized).

Stop Screw Press 11KR01Time delay 3 seconds.



Stop Plug Screw 11KR02Time delay 3 seconds.

Stop Shredder 11KR03Time delay 3 seconds.

Stop Preheater 11KR04Time delay 3 seconds.

Stop Infeeder 11KR05Time delay 5 seconds.

If no more required by any other sub-system, stop Loop 3 filtrates pump 13PPC18.


Stop Disperser 11KR06

The system is stopped

Note: Tower extraction pump 12PPC05 is stopped when no more pulp is required on downstream process. This action is independent from upstream process stop sequence.



PROCESS DESCRIPTION


PRINTING - WRITING

WASHINGFINAL STORAGE

WASHING & FINAL STORAGEPage 224/264


15 WASHING & FINAL STORAGE

1.65 DESCRIPTION


Washing feed chest .............................................................................12CPA06

Washing feed chest agitator ....................................................................................12AG07

Washing feed chest extraction pump.......................................................................12PPC08

Washing feed pump .............................................................................13PPC01

DNT Washer 1 ..............................................................................13LAV02

DNT Washer 2 ..............................................................................13LAV03

Washer Medium pressure showers feed pump........................................................13PPC05

Washer High pressure showers feed pump.............................................................13PPC06

Stand Pipe ...............................................................................14CP10

Transfer MC pump to Storage tower........................................................................14PMC11

Final storage tower .............................................................................14CPA04

Final storage tower agitator .....................................................................................14AG05

Final storage tower extraction pump........................................................................14PPC06



1.65.2 Washer basics

1.65.2.1 DNT Washer Description

The washer thickener DNT 200 is a high-speed double nip thickener machine, using a synthetic wire for efficient removal of ink, clay and other contaminants.

The DNT consists of an enclosed endless wire running on two cantilevered rolls (driven couch roll, breast roll with grooves), driven by pulley and V-belts with vari-able frequency drive, with the following elements:

- The stock inlet connection to DNT & pressurized flow distribution Head-box;- Breast roll, grooved;- Couch roll, smooth, driven by V-belt & variable speed drive;- Oscillating Stock discharge doctor;- Accept stock discharge screw conveyor & drive;- Oscillating HP shower (needle-30 Bars);- Fixed MP shower (Fan-8 bars).


DNT Overview:

Breast Roll (with grooves)

Filtrates Outlet

Accept Screw

Couch Roll

DNT Head-box

Stock inlet0,8-2,5%

Oscillating HP Shower

Stock Accept8-12%

Fixed MP Shower


1.65.3 DNT Washer operation

The DNT Washer consists of a flow distribution nozzle, two rolls and a synthetic wire, which acts as the dewatering media.

The DNT Washer operates by feeding stock from the flow distribution nozzle into the nip formed by the breast roll and the wire. The stock is fed at a high velocity into this nip for effective dewatering and high capacities for a relatively small roll width.The breast roll is grooved to provide high capacity and also eliminates the need for the doctor blade.

After the feed nip, the wire continues around the breast roll where the stock con-tinues to be dewatered. As the wire separates from the breast roll, a stock mat has been formed.This stock mat travels with the wire to the couch roll where it undergoes addi-tional dewatering.

The stock mat is then doctored into the repulper screw conveyor where it is re-moved from the DNT Washer at approximately 10-12% consistency.

A cowling encloses the DNT Washer and allows the white water from the unit to be collected and discharged at one central location.This cowling also eliminates splashing from the unit and makes the operation clean and safe. White water consistency from the DNT Washer depending on the ash content and fiber length on the stock and operating conditions.

The wire is guided by two V-guides resting on both tending & drive sides of the couch & breast rolls. The wire tension is adjusted mechanically by hand-wheel & gear screw jack on tending side and checked locally on load-cell, with low & high tension alarms.

The MP Shower (Fan) & HP oscillating high-pressure (needle) shower clean the wire continuously after thick stock discharge.

Applications for the DNT Washer include deashing of stock for tissue production as well as dispersed ink removal for tissue, newsprint, and fine papers.




1.65.4.1 Washing area feed and by-pass

From the Storage tower 12CPA03, pump 12PPC05 feeds the stock chest 12CPA06 that is a constant level working chest.Chest 12CPA06 level is controlled by LIC11070 commanding the stock quantity required upstream the system via control valve LCV-11070 on stock feed pipe.

Moreover, washing area design capacity allows a complementary pulp produc-tion, transferred from parallel deinking line (called “Existing VOITH line”) and col-lected in transfer chest 12CPA06.

Transfer chest 12CPA06 serves also to homogenize finely stock extracted from Bleaching step (in consistency, air content, …).

From this chest, extraction pump 12PPC08 transfers pulp to Washing area at consistency ~4% regulated by controller NIC11075 and addition of Loop 3 fil-trates from dilution pump 13PPC09.This transfer flow is adjustable through Flowmeter FIC12005.Control valve FCV-12005 is the basis weight valve for 3rd loop of deinking line: its opening fixes the production rate of Loop 3.

As transmitter NIC11075 also continuously measures consistency at this point, then instantaneous washing feed production (P3-12005) can be calculated and checked (and corrected if necessary through FIC12005 set-point) at any time by operator.

As Ash content in final deinked pulp is proportional to production ratio sent to washing system (and then to filtrate flow to be treated by Micro-flotation), a by pass-line from pump 12PPC05 delivery (through On-Off valve AV-11105) sends stock directly to Final storage tower 14CPA04.This by-pass flow is adjustable through Flowmeter FIC15095 and corresponding production is calculated with stock consistency measured by NRC11050.

The sum of Washing feed and By-pass productions gives the stock quantity to be processed by the 2 upstream deinking loops.Operator checking is required to set both productions to values compatible with Loop 1 & Loop 2 design operating capacities (by checking levels stability in Towers 07CPA01 & 12CPA03).

1.65.4.2 Washing feed pump 13PPC01

DNT washers are fed from pump 13PPC01 connected on Loop 3 filtrate tank 13CE08.

DNT Washers feed pulp consistency has also a direct influence on ash content removal in final stock and is adjustable through inlet flow controllers FIC1015 (for 13LAV02) and FIC12076 (for 13LAV03).



In fact: Water dilution flow (from pump 13PPC01 suction) is the subtraction of thick stock feed flow FT-12005 from DNT total inlet flow (sum of measurements FT-12015 and FT-12076).Then DNT inlet stock consistency value can be obtained from thick stock consist-ency measured by NT-11075.

DNT washers can operate with a feed stock consistency comprised between 1 and 3%.

DNT washers feed pump 13PPC01 is equipped with a variable speed motor con-troller SIC12008 in order to adapt delivery flow to operating conditions, varying in a large margin (due to feed production and DNT inlet consistency variations – See above).

Moreover the possibility is kept to feed a third DNT (in a parallel deinking line) if required by Paper Machine settings (in case of improved production and/or qual-ity).

1.65.4.3 DNT washers

Washers 13LAV02 & 13LAV03 thicken the 1-3% stock flow coming from Loop 2 storage tower 12CPA03.

The DNT Washer head-box inlet pressures are measured by PI12020 (for 13LAV02) & PI12080 (for 13LAV03).

The DNT Main drive motors are speed controlled - at fixed speed manually set from DCS by operator, through SIC12031 (for 13LAV02) & SIC12091 (for 13LAV03).

Each washer fixed medium pressure shower is provided with water from pump 13PPC05 (at pressure 8 bars) and through On/Off valves AV-12040 (for 13LAV02) & AV-12100 (for 13LAV03).

Each washer oscillating High pressure shower is provided with water from pump 13PPC06 (at pressure 25 bars) and through On/Off valves AV-12045 (for 13LAV02) & AV-12105 (for 13LAV03).

HP showers oscillations are: Started by commands HS-12050 (for 13LAV02) & HS-12110 (for

13LAV03) Monitored by Oscillation alarm signals XS-12050 (for 13LAV02) & XS-

12110 (for 13LAV03).

Washer doctors oscillations are: Started by commands HS-12025 (for 13LAV02) & HS-12085 (for

13LAV03) Monitored by Doctor Oscillation alarm signals XS-12025 (for 13LAV02)

& XS-12085 (for 13LAV03)



Each transversal wire movement is monitored by position detectors on Drive side & Tending side, transmitted to DCS by Wire position alarms.Alarms ZS-12030 (for 13LAV02) or ZS-12090 (for 13LAV03) stops the corres-ponding DNT Main drive.

Each Washer wire tension is monitored by local load cell with remote alarms WS-12065 (for 13LAV02) and WS-12125 (for 13LAV03) signal to DCS.These Low tension alarms stop the corresponding DNT Main drive.

Each Washer Breast roll rotation is monitored by speed switches SSL-12060 (for 13LAV02) and SSL-12120 (for 13LAV03) alarm on Breast roll.This alarm while DNT drive is running indicates a slackening of the wire tension or V-belt drive incident, and stops the corresponding DNT Main drive.

If necessary, water lines from “FRESH WATER” to each Washer inlet (via On-Off valves AV-12013 for 13LAV02 & AV-12075 for 13LAV03) and to washer extractor screw (via On-Off valves AV-12035 for 13LAV02 & AV-12095 for 13LAV03) allow washing in manual the equipment after its shut-down (for example before a sev-eral days stop or before a maintenance intervention).

Washing filtrates flow to Micro-Flotation feed tank 13CE07.

Each accept stock screw conveyor rotation is monitored by speed switches SSL-12055 (for 13LAV02) and SSL-12115 (for 13LAV03).These alarms indicate a screw conveyor drive incident, and stop the correspond-ing DNT Main drive and screw conveyor drive.

Washed pulp is extracted from washer outlet screw and falls into stand pipe 14CP10.

1.65.4.4 Transfer MC pump 14PMC11

Note: The following description for MC pump operation & associated regulations correspond with a Sulzer pump type.This paragraph is to be adapted and/or corrected in case of any other supplier.

Stock at 10-12% falls by gravity from Washers 13LAV02 and 13LAV03 Repulping screws into the MC Pump Stand-Pipe 14CP10.



In addition, LICS15090 controls valve LCV-15090 on dilution water to Stand-pipe provided by PM Water.

The MC Pump 14PMC11 pumps the stock to Final Storage tower 14CPA04.



1.65.4.5 Final Storage tower 14CPA04

Storage tower 14CPA04 collects accept pulp from washer (via MC pump 14PMC11) and pulp from washing by-pass (through controller FIC15095).

Storage tower 14CPA04 level is measured by LIS15040.

High Level LIS115040 is one of the main levels on the line, to be monitored by operator to control the production & stability on loop 3 by acting on Loop 3 pro-duction set-point (through flow controllers FIC12005 for washing feed and FIC15095 for washing by-pass).Modification of Loop 3 production set-point may have also a repercussion on Loop 2 and Loop 1 production set-points.

The Storage tower must have a minimum level of filtrates or stock prior to feeding thick stock - to prevent block agitator or extracting system. This requires pre-filling on filtrates prior to start the line. Operator does this filling manually from DCS.

Storage tower 14CPA04 is equipped with a horizontal agitator 14AG05.

Pump 14PPC06 extracts the stock from Storage tower to Paper Machine area.This transfer flow is adjustable through flow controller FIC15060.

Tower extracted pulp consistency is controlled by NRC15045 and adjusted with addition of PM Filtrates.Most part of this dilution flow is directed (via control valve QCV-15050) to Tower 14CPA04 bottom diluting zone in order to reduce consistency to around approx. 5%.Remaining dilution water flow is directed (via control valve NCV-15045) to suction of pump 14PPC06 where consistency reaches more finely 4-4,5%.Controller QC15050 operates as a proportional ratio in order to adjust associated valves (QCV-15050 and NCV-15045) opening values and then the sharing of total dilution flows (usually 70% of total flow through valve QCV-15050 and 30% through NCV-15045).

Extraction pump 14PPC06 outlet pressure is controlled via PIC15055 and adjus-ted with control valve PCV-15055 or On/Off valve AV-15080 on 2 parallel recircu-lation pipes back to Storage tower bottom.- The smallest diameter valve PCV-15055 will be enabled with controller

PIC15055 during normal operation (when pressure recirculation flow is lim-ited).

- The biggest diameter On/Off valve AV-15080 will be used during transitory phases (like start-up) requiring a bigger pressure recirculation (even a total re-circulation).

During start-up, the recirculation at the bottom of the tower is turned on in order to reach an appropriate consistency before transfer to Paper Machine:

On/Off valve AV-15080 opens. Control valve FCV-15060 on transfer pipe is forced closed.



When desired consistency is obtained; and stabilized, the full recirculation is shut down:

On/Off valve AV-15080 closes Pump 14PPC06 outlet pressure is controlled by PIC15055 in AUTO

mode and through control valve PCV-15055. Pulp is sent downstream.

Brightness of extracted pulp from Tower 14CPA04 is measured by transmitter AIR15065 and displayed/recorded.

PH of extracted pulp from Tower 14CPA04 is measured by transmitter AIR15070 and displayed/recorded.




Washer: 2 x DNT200

For 2 DNT 200: Inlet flow: 1200 m3/h maximum

Accept capacity if feed at 3%: 330 BDT/24h maximum300 BDT/24h optimum






FIC 15095 Flow control of Washing by-pass pulp 0-350 m3/h

LIC 11070 Transfer chest 12CPA06 level control 5% 15% 85% 95% 0-40 m3

NIC 11075Consistency control of pulp transferred to Washing area

0 to 5%

FIC 12005 Flow control of Washing feed pulp 0-450 m3/h

P3 12005Washing feed production indication

(Obtained from NT-11075 & FT-12005)Software only

SIC 12008Washers feed pump 13PPC01 motor speed Control

0-100%

FIC 12015 Washer 13LAV02 inlet Flow control 0-800 m3/h

PI 12020Washer 13LAV02 inlet pressure indica-tion

0,5 1 0-2 Bars

SIC 12031 Washer 13LAV02 motor speed Control 0-100%

XS 12025 Washer 13LAV02 oscillating doctor alarm

HS 12025Washer 13LAV02 oscillating doctor ON command

ZS 12030 Washer 13LAV02 wire position alarm

XS 12050Washer 13LAV02 HP oscillating shower alarm

HS 12050Washer 13LAV02 HP oscillating shower ON command

SSL 12055Washer 13LAV02 extraction screw rota-tion alarm Speed switch

*

SSL 12060Washer 13LAV02 Breast Roll Rotation alarm Speed switch

*

WS 12065 Washer 13LAV02 wire tension alarm

…/…





FIC 12076 Washer 13LAV03 inlet Flow control 0-800 m3/h

PI 12080Washer 13LAV03 inlet pressure indica-tion

0,5 1 0-2 Bars

SIC 12091 Washer 13LAV03 motor speed Control 0-100%

XS 12085 Washer 13LAV03 oscillating doctor alarm

HS 12095Washer 13LAV03 oscillating doctor ON command

ZS 12090 Washer 13LAV03 wire position alarm

XS 12110Washer 13LAV03 HP oscillating shower alarm

HS 12110Washer 13LAV03 HP oscillating shower ON command

SSL 12115Washer 13LAV03 extraction screw rota-tion alarm Speed switch

*

SSL 12120Washer 13LAV03 Breast Roll Rotation alarm Speed switch

*

WS 12125 Washer 13LAV03 wire tension alarm


5% 15% 85% 95% 0-100%

SIC 15075 MC Pump 14PMC10 motor speed control 0-100%

LIS 15040 Storage tower 14CPA04 level control 5% 15% 85% 95% 0-600 m³

NRC 15045Storage tower 14CPA04 extracted pulp consistency control

0 to 5%

QC 15050Ratio repartition for Storage tower 14CPA04 pulp dilution water flow

0-100%

PIC 15055Storage tower 14CPA04 extracted pulp pressure control

0–4 Bars

FIC 15060Flow control of pulp sent to Paper Ma-chine

0-400 m3/h

AIR 15065Brightness indication of pulp sent to Pa-per Machine

AIR 15070PH indication of pulp sent to Paper Ma-chine




1.68.1 Transfer chest 12CPA06

247- TRANSFER CHEST LEVEL LIC11070 TO AGITATOR 12AG07

If Transfer chest level LIC11070 is Low-LowThen Stop Agitator 12AG07

If Transfer chest level LIC11070 is LowThen Inhibit Start Agitator 12AG07

If Transfer chest level LIC11070 is not LowAnd Agitator 12AG07 in DCS Auto mode


248- INTERLOCKS TO TRANSFER PUMP 12PPC08

If Transfer chest 12CPA06 level LIC11070 is LowOr Washers feed pump 13PPC01 is not runningOr Loop 3 dilution pump 13PPC09 is not running

Then Transfer pump 12PPC08 is stopped.

If Transfer chest 12CPA06 level LIC11070 is Low

Then Inhibit start of Transfer pump 12PPC08

249- INTERLOCKS FROM TRANSFER PUMP 12PPC08 TO CONTROL VALVE FCV-12005 ON DELIVERY PIPE

If Transfer pump 12PPC08 is not runningThen Control valve FCV-12005 is forced closed

If Transfer pump 12PPC08 is runningThen With on delay T=5s, Control valve FCV-12005 in Auto opens



250- INTERLOCKS TO DILUTION CONTROLLER NIC11075

If Transfer pump 12PPC08 is not runningOr Loop 3 dilution pump 13PPC09 is not running

Then Dilution controller NIC11075 is disabled with control valve NCV-11075

251- (RESERVE)

1.68.2 Washers feed pump 13PPC01

252- INTERLOCKS to WASHERS FEED PUMP 13PPC01

If Loop 3 water tank 13CE08 level controller LIS13005 is lowIf DNT 13LAV02 Ready Status AND DNT 13LAV03 Ready Status NOT

READY, with On-delay T=15s

Then Washers feed pump 13PPC01 is stopped.

253- FEED PUMP 13PPC01 to DNT WASHERS INLET FLOW CONTROLLERS

If Washers feed pump 13PPC01 is not runningThen DNT inlet control valves FCV-12015 and FCV-12076 are forced closed.

If Washers feed pump 13PPC01 is runningThen With on delay T=5s, DNT inlet control valves FCV-12015 and FCV-

12076 in Auto are opened.

254- FEED PUMP 13PPC01 to STOCK FEED FLOW CONTROLLER

If Washers feed pump 13PPC01 is not running

Then Stock feed flow control valve FCV-12005 is forced closed.

255- (RESERVE)



1.68.3 Washer 13LAV02

256- INTERLOCKS TO WASHER 13LAV02

If Water pump 13PPC05 for MP shower is stoppedOr Water pump 13PPC06 for HP shower is stoppedOr Tensioning wire WS12065 is not correct

Then Washer 13LAV02 is stopped.

257- MC PUMP 14PMC11 INTERLOCKS TO WASHER 13LAV02 OUTLET SCREW

If MC pump 14PMC11 stand pipe level LICS15090 is High-High

Then Washer 13LAV02 Repulping Screw is stopped.

258- DNT WASHER 13LAV02 READY STATUS

DNT WASHER 13LAV02 Status READY allows feeding pulp to the Washer, Status NOT READY forbids feeding pulp to the Washer.

If MC pump 14PMC11 stand pipe level LICS15090 is Not High-HighAnd Storage tower 14CPA04 level LIS15040 is not High-HighAnd DNT drive 13LAV02 is running with T=15s On-delayAnd DNT extraction screw is runningAnd HP Shower oscillation XS12050 is NOT alarm no-oscillationAnd Oscillating Shower HS12050 is ONAnd Doctor oscillation XS12025 is NOT alarm no-oscillationAnd Doctor oscillator HS12025 is ONAnd Water pump 13PPC05 for MP shower is runningAnd Water pump 13PPC06 for HP shower is running

Then WASHER STATUS is set to READY

If MC pump 14PMC11 stand pipe level LICS15090 is High-High for T=15sOr Storage tower 14CPA04 level LIS15040 is High-High for T=15sOr DNT drive 13LAV02 is not runningOr DNT extraction screw is not runningOr HP Shower oscillation XS12050 is alarm no-oscillation with T=120s Off-

delayOr Oscillating Shower HS12050 is Off with T=120s off-delay Or Doctor oscillation XS12025 is alarm no-oscillation with T=120s Off-delayOr Doctor oscillator HS12025 is OFF with T=120s off-delayOr Water pump 13PPC05 for MP shower is stoppedOr Water pump 13PPC06 for HP shower is stopped

Then WASHER STATUS is set to Not READY



Notes: - MP shower system does not interlock WASHER STATUS, only step for

group-start (Wire wetting);

259- WASHER SECURITY INTERLOCKS: WIRE TENSION & POSITION

If Washer 13LAV02 Wire Tension WS12065 is Alarm

Then Washer 13LAV02 Main drive is stopped

If Washer 13LAV02 Wire Position ZS12030 is Alarm

Then Washer 13LAV02 Main drive is stoppedAnd Washer outlet screw is stopped

260- WASHER SECURITY INTERLOCKS: SPEED SWITCHES

If Washer 13LAV02 Main drive is running with start-up override T=5 sAnd Breast roll speed switch SSL12060 is alarm


If Washer 13LAV02 outlet screw is running with start-up override T=5 sAnd Washer screw speed switch SSL12055 is alarm

Then Washer 13LAV02 outlet screw is stopped

261- WASHER 13LAV02 HP SHOWER INTERLOCKS

If HP Shower oscillator HS12050 is OFF Or HP Shower oscillation XS12050 signal is OK

Then HP Shower oscillation monitor XS12050 is set to OK.

If HP Shower oscillator HS12050 is ON with T1=5s on-delayAnd HP Shower oscillation XS12050 signal is Zero with T1=5s on-delay

Then HP Shower oscillation monitor XS12050 is reset to Alarm



If DNT MP Shower pump 13PPC05 is not running with T=5s On-delayThen MP Shower AV-12035 is forced Closed (Hard interlock)

If DNT HP Shower pump 13PPC06 is not running with T=5s On-delayOr DNT washer 13LAV02 main drive is not runningOr XS12050 is Alarm no oscillation with T2=15s off-delay

Then HP Shower AV-12045 is forced Closed (Hard interlock)

Note: Oscillation alarm is overridden T1=5s after start of oscillation, and interlock to shower valve is active only after T2=15s of alarm.

262- WASHER 13LAV02 DOCTOR OSCILLATION

If Doctor oscillator HS12025 is OFF Or Doctor oscillation XS12025 signal is OK

Then Doctor oscillation monitor XS12025 is set to OK.

If Doctor oscillator HS12025 is ON with T1=5s on-delayAnd Doctor oscillation XS12025 signal is Zero with T1=10s on-delay

Then Doctor oscillation XS12025 is reset to Alarm

263- (RESERVE)

1.68.4 Washer 13LAV03

264- INTERLOCKS TO WASHER 13LAV03

If Water pump 13PPC05 for MP shower is stoppedOr Water pump 13PPC06 for HP shower is stoppedOr Tensioning wire WS12125 is not correct

Then Washer 13LAV03 is stopped.

265- MC PUMP 14PMC11 INTERLOCKS TO WASHER 13LAV03 OUTLET SCREW

If MC pump 14PMC11 stand pipe level LICS15090 is High-High

Then Washer 13LAV03 Repulping Screw is stopped.



266- DNT WASHER 13LAV03 READY STATUS

DNT WASHER 13LAV03 Status READY allows feeding pulp to the Washer, Status NOT READY forbids feeding pulp to the Washer.

If MC pump 14PMC11 stand pipe level LICS15090 is Not High-HighAnd Storage tower 14CPA04 level LIS15040 is not High-HighAnd DNT drive 13LAV03 is running with T=15s On-delayAnd DNT extraction screw is runningAnd HP Shower oscillation XS12110 is NOT alarm no-oscillationAnd Oscillating Shower HS12110 is ONAnd Doctor oscillation XS12085 is NOT alarm no-oscillationAnd Doctor oscillator HS12085 is ONAnd Water pump 13PPC05 for MP shower is runningAnd Water pump 13PPC06 for HP shower is running

Then WASHER STATUS is set to READY

If MC pump 14PMC11 stand pipe level LICS15090 is High-High for T=15sOr Storage tower 14CPA04 level LIS15040 is High-High for T=15sOr DNT drive 13LAV03 is not runningOr DNT extraction screw is not runningOr HP Shower oscillation XS12110 is alarm no-oscillation with T=120s Off-

delayOr Oscillating Shower HS12110 is Off with T=120s off-delay Or Doctor oscillation XS12085 is alarm no-oscillation with T=120s Off-delayOr Doctor oscillator HS12085 is OFF with T=120s off-delayOr Water pump 13PPC05 for MP shower is stoppedOr Water pump 13PPC06 for HP shower is stopped

Then WASHER STATUS is set to Not READY

Notes: - MP shower system does not interlock WASHER STATUS, only step for

group-start (Wire wetting);

267- WASHER SECURITY INTERLOCKS: WIRE TENSION & POSITION

If Washer 13LAV03 Wire Tension WS12125 is Alarm


If Washer 13LAV03 Wire Position ZS12090 is Alarm

Then Washer 13LAV09 Main drive is stoppedAnd Washer outlet screw is stopped



268- WASHER SECURITY INTERLOCKS: SPEED SWITCHES

If Washer 13LAV03 Main drive is running with start-up override T=5 sAnd Breast roll speed switch SSL12120 is alarm

Then Washer 13LAV03 Main drive is stopped (Hard Interlock)

If Washer 13LAV03 outlet screw is running with start-up override T=5 sAnd Washer screw speed switch SSL12115 is alarm

Then Washer 13LAV03 outlet screw is stopped (Hard Interlock)

269- WASHER 13LAV03 HP SHOWER INTERLOCKS

If HP Shower oscillator HS12110 is OFF Or HP Shower oscillation XS12110 signal is OK

Then HP Shower oscillation monitor HS12110 is set to OK.

If HP Shower oscillator HS12110 is ON with T1=5s on-delayAnd HP Shower oscillation XS12110 signal is Zero with T1=5s on-delay

Then HP Shower oscillation monitor XS12110 is reset to Alarm

If DNT MP Shower pump 13PPC05 is not running with T=5s On-delayThen MP Shower AV-12095 is forced Closed (Hard interlock)

If DNT HP Shower pump 13PPC06 is not running with T=5s On-delayOr DNT washer 13LAV03 main drive is not runningOr XS12110 is Alarm no oscillation with T2=15s off-delay

Then HP Shower AV-12105 is forced Closed (Hard interlock)

Note: Oscillation alarm is overridden T1=5s after start of oscillation, and interlock to shower valve is active only after T2=15s of alarm.



270- WASHER 13LAV03 DOCTOR OSCILLATION

If Doctor oscillator HS12085 is OFF Or Doctor oscillation XS12085 signal is OK

Then Doctor oscillation monitor XS12085 is set to OK.

If Doctor oscillator HS12085 is ON with T1=5s on-delayAnd Doctor oscillation XS12085 signal is Zero with T1=10s on-delay

Then Doctor oscillation XS12085 is reset to Alarm

271- (RESERVE)

1.68.5 Common to both Washers

272- INTERLOCK TO MP SHOWER PUMP 13PPC05

If Loop 3 dilution water pump 13PPC09 is not running

Then Stop MP Shower Pump 13PPC05

273- INTERLOCK TO HP SHOWER PUMP 13PPC06

If FRESH WATER not available (interlock to be defined)

Then Stop HP Shower Pump 13PPC06

274- (RESERVE)

275- (RESERVE)



1.68.6 Transfer MC pump 14PMC11

276- INTERLOCKS TO MC PUMP 14PMC11

If Storage Tower 14CPA04 level LIS15040 is alarm High-High for T=5sOr MC pump Stand Pipe level LICS15090 is Low-Low for 30s




Then Level controller LICS15090 is disabledAnd Control valve LCV-15090 if in Auto is closedAnd Slave On/Off valve AV-15100 is forced closed



And Output to valve LCV-15090 is enabledAnd Slave On/Off valve AV-15100 opens

278- PM WATER INTERLOCK TO MC PUMP WATER CONTROL VALVES

If PM WATER network not under pressure (interlock to be defined)Then Control valve LCV-15090 is forced closed.

If PM WATER network not under pressure (interlock to be defined)And MC Pump 14PMC11 is running


279- (RESERVE)



1.68.7 Storage tower 14CPA04

280- STORAGE TOWER LEVEL LIS15040 TO AGITATOR 14AG05

If Storage tower 14CPA04 level LIS15040 is LowThen Stop Agitator 14AG05

If Storage tower 14CPA04 level LIS15040 is LowThen Inhibit Start Agitator 14AG05

If Storage tower 14CPA04 level LIS15040 is not LowAnd Agitator 14AG05 is DCS Auto mode


281- LEVEL LIS15040 HIGH_HIGH INTERLOCK TO DILUTION VALVES

If Storage tower 14CPA04 level LIS15040 is High-High


Note: this interlock is designed to prevent adding dilution filtrates to a full tower.

282- INTERLOCKS TO TOWER EXTRACTION PUMP 14PPC06

If Storage tower 14CPA04 level LIS15040 is LowOr Agitator 14AG05 is stopped

Then Pump 14PPC06 is stopped.

If Storage tower 14CPA04 level LIS15040 is LowThen Inhibit start of pump 14PPC06.

(This interlock prevents tripping the pump motor on start-up by extracting pulp that is not properly agitated & homogenized in the bottom of the Tower).

283- TOWER EXTRACTION PUMP 14PPC06 TO REGULATIONS ON DELIVERY PIPES


Then Control valve FCV-15060 on delivery line is forced closed.



284- INTERLOCKS TO CONSISTENCY CONTROLS NRC15045 & QC15050

If Tower extraction pump 14PPC06 is not runningOr PM WATER network not under pressure (interlock to be defined)


285- INTERLOCKS TO TOWER EXTRACTION PRESSURE CONTROL PIC15055


Then Controller PIC15055 is disabled with control valve PCV-15055 and On/Off valve AV-15080 forced closed.

286- (RESERVE)

ALARMS

287- SEALING WATER

If Washing area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


288- COMPRESSED AIR

If Washing area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


289- STORAGE TOWER 14CPA04 LEVEL LIS15040

If Storage tower 14CPA04 level LIS15040 is High


290- (RESERVE)



1.69 OPERATION

1.69.1 Start-up

This loop begins only if the loop “LOOP 3 WATER CLARIFICATION AND DIS-TRIBUTION" is running.

1.69.1.1 Start of the loop



Low)- “PM water” network is under pressure- “Fresh water” network is under pressure- Continuous water pump 05PPC07 must be running- Level control LIC13010 of filtrate tank 13CE07 must be not High- Level control LIC13005 of dilution tank 13CE08 must be not Low- Level control LIS15040 of Storage Tower 14CPA04 must be not High AND

not Low-Low- For washer 13LAV02: Wire tension WS12065 is not alarm and Wire Position

ZS12030 is not alarm- For washer 13LAV03: Wire tension WS12125 is not alarm and Wire Position

ZS12090 is not alarm

Note: If Storage Tower 14CPA04 level is Low, operator needs to pre-fill the Tower with PM Water filtrates.

Start loop 3 dilution pump 13PPC09 if not already running.

WASHER 13LAV02

Start of Washer outlet screw motor.

Start Washer 13LAV02 main drive motor.

Start Washer 13LAV02 Doctor oscillation (by HS12025).

Start of water system for DNT showers: Start of MP shower water pump 13PPC05 (if not already started by

13LAV03) After T=5s, open MP shower On/Off valve AV-12035 Start HP oscillator HS12050 When HP oscillation XS12050 is OK, start of HP shower water pump

13PPC06 (if not already started by 13LAV03) and open HP shower On/Off valve AV-12045



WASHER 13LAV03

Start of Washer outlet screw motor.

Start Washer 13LAV03 main drive motor.

Start Washer 13LAV03 Doctor oscillation (by HS12085).

Start of water system for DNT showers: Start of MP shower water pump 13PPC05 (if not already started by

13LAV02) After T=5s, open MP shower On/Off valve AV-12095 Start HP oscillator HS12110 When HP oscillation XS12110 is OK, start of HP shower water pump

13PPC06 (if not already started by 13LAV02) and open HP shower On/Off valve AV-12105

1.69.1.2 Production

The washing area starts with start of transfer pump 12PPC08 and opening of control valve FCV-12005 on transfer pipe from chest 12CPA06.

Transfer chest 12CPA06 should have been first filled with pulp from Tower 12CPA03 extraction pump 12PPC05 (and/or with pulp transferred from parallel VOITH deinking line).Through interlocks associated agitator 12AG07, pump 12PPC08 and consistency regulation NIC11075 will be enabled to start as soon as chest level LIC11070 reaches a sufficient level.

On the other hand, if a part (even the totality) of production by-passes washing area, pump 12PPC05 transfers pulp directly to storage tower 14CPA04 (to be already filled with filtrates or pulp).

Stock feed can proceed to Washers when the DNT Washers are Ready: DNT running with MP & HP showers, screw conveyor, and downstream systems.

NB: The process block can run few minutes in water mode.

Transfer MC-Pump 14PMC11 to be started when washers are fed with pulp.All items of sub-system - in Auto mode - start according to interlocks defined above:- Dilution to Stand-pipe opens by interlock on MC Pump start-order - Controller LICS15090 & SIC15075 are enabled when MC-Pump is running;



1.69.2 Operation


Monitoring of pressurized water pressures. Monitoring of consistencies (Water and stock). Monitoring of safety device (wire position, oscillation, speed switch, …) Checking of Storage Tower level 14CPA04 (one of the main paramet-

ers in the line).

1.69.3 Shutdown


The process bloc stops in production with stop of transfer pump 12PPC08 and closing of control valve FCV-12005 on transfer pipe from chest 12CPA06.

Then chest 12CPA06 feed pump 12PPC05 can be stopped (if no more required for washing by-pass, Flow controller FIC15095 set point to 0).Eventual pulp transfer from parallel VOITH deinking pulp is also stopped.


Reset DNT Washers status to Not READY. With Interlocks, feed pump 13PPC01 stops.

Planned stop of Washer will lead operator to first stop pulp feed closing of con-trol valve FCV-12005 (on transfer pipe from chest 12CPA06) and run Washing area on Filtrates through the Washer to flush the pulp out of the system for 5 minutes.

Note: For a planned shut superior to 2 hours, it is recommended to pay a special attention to the cleaning time to avoid blocking the wire with dried fiber or chem-ical deposits in relation with an insufficient cleaning of the wire on shut-down.

If necessary, flush DNT inlet head boxes with opening of On-Off valves AV-12013 for 13LAV02 & AV-12075 for 13LAV03.

If necessary, clean DNT outlet screw with opening of On-Off valves AV-12035 for 13LAV02 & AV-12095 for 13LAV03.



WASHER 13LAV02 STOP

Stop of water system for DNT showers: Close HP shower On/Off valve AV-12045 Stop HP oscillator (with HS12050) and Stop of Washer 13LAV02 oscil-

lating doctor (with HS12025). Close MP shower On/Off valve AV-12035 Stop of showers water pumps 13PPC05 and 13PPC06 (if no more used

by 13LAV03).

Stop of Washer 13LAV02 main drive motor.

Stop of Washer outlet screw 13LAV02 motor.

WASHER 13LAV03 STOP

Stop of water system for DNT showers: Close HP shower On/Off valve AV-12105 Stop HP oscillator (with HS12110) and Stop of Washer 13LAV02 oscil-

lating doctor (with HS12085). Close MP shower On/Off valve AV-12095 Stop of showers water pumps 13PPC05 and 13PPC06 (if no more used

by 13LAV02).

Stop of Washer 13LAV03 main drive motor.

Stop of Washer outlet screw 13LAV03 motor.

Transfer pump 14PMC11 is stopped through interlocks when no more pulp comes from DNT Washers.

Note: Tower extraction pump 14PPC06 is stopped when no more pulp is required for Paper Machine. This action is independent from upstream process stop se-quence.



PROCESS DESCRIPTION


PRINTING - WRITING

LOOP 3 WATER DISTRIBUTION& MICRO-FLOTATION

LOOP 3 WATER DISTRIBUTION & MICRO-FLOTATIONPage 251/264


16 LOOP 3 WATER DISTRIBUTION & MICRO-FLOTATION

1.70 DESCRIPTION

1.70.1 Itemization

Micro-flotation feed tank...........................................................................................13CE07

Microflotator feed pump............................................................................................13PPC10

Filtrate transfer pump to Voith line...........................................................................13PPC19

Clarified water tank ...............................................................................13CE08

Loop 3 water dilution pump......................................................................................13PPC09

Loop 3 water transfer pump to Loop 2.....................................................................13PPC11

Loop 2 dispersion dilution pump...............................................................................13PPC18

Microflotator .............................................................................13POS12

Microflotation circulation pump.................................................................................13PPC13

Sludge chest .............................................................................13CPA14

Sludge chest agitator ...............................................................................13AG15

Sludge chest extraction pump..................................................................................13PPC16



1.70.2 Microflotator PPM basics

1.70.2.1 Microflotator PPM Description

The Poseidon PPM Dissolved Air Flotator (DAF) is an open top separator de-signed to clarify filtrates by removing suspended solids with dissolved air gener-ated micro-bubbles.

Poseidon PPM System Equipment

The Poseidon PPM consists of:

- A stainless steel parallelepedic-shaped tank, with nozzles as follows:Inlet nozzle with mixing chamber, withFlocculent injection nozzles; Connection from pressurization system;Clarified filtrates accept nozzle;Filling nozzle; Connection to Poseipump & pressurization system, Top surface sludge discharge connection;Settled sludge discharge front (Purge);Settled sludge discharge bottom (Purge).

- An internal POSEIPACK assembly of plates, designed to intercept low buoy-ancy particles and promote flock build-up;

- A mechanical Sludge Thickener on top of the unit with gear drive & finger paddles.

- A mechanical sludge layer discharge scraper, pushing the sludge layer into the discharge trough, with mechanically adjustable speed;

- Pressurization POSEIPUMP, with local pressurization control panel, pressur-ization pipe and pressure relief valve.

1.70.2.2 Microflotator PPM operation

The adequate flocculation chemistry is added to the filtrate flow to be treated, prior to introduction into the PPM unit.

The incoming filtrates are pumped to the unit's mixing chamber, where a recircu-lating flow of dissolved air containing filtrates is mixed to the incoming filtrates flow.

The dissolved air containing filtrate flow is obtained by recirculating of part of the accepted filtrate flow of the unit through the pressurization & air introduction sys-tem - with special POSEIPUMP and pressurization/air introduction control panel.

The pressure release on the dissolved air containing filtrate flow generates micro-bubbles, which form in and adhere to the suspended solids & flocks.



At the inlet of the unit, heavy non-floatable particles settle to the bottom of the unit in the sludge cone. A drainage pipe at the unit's lower point enable to remove depositing heavy particles by periodic flushing.

The particles & flocks surrounded by micro-bubbles rise to the surface, and are separated according to their buoyancy as follows:

Big fast-rising particles rise directly to the unit's open surface, Small slow-rising particles are intercepted in the Poseipack collection

plates within the unit, where the plate design build-up flock size until the increased buoyancy allows them to reach the unit's open surface.

The particles & flocks accumulating at the surface of the unit constitute the sludge layer on the unit. A rotating scraper removes the thickened sludge to a hopper.

Poseidon Operation

The operation of a PPM is typically set at constant & controlled hydraulic filtrates feed flow rate.However several sequences trim this continuous operation (see associated Func-tion Chart separately supplied).

The recirculating flow is adjusted on start-up to a set Poseipump delivery pres-sure; the Air pressurization pressure & flow are set with the local panel pressure reducer and flow-meter. The system operates in these fixed conditions. A proper recirculation & aeration is controlled by observation of the flow obtained at the discharge of manual vent valve from pressurization tube to the top of the Pos-eidon unit (milky aspect).

Sludge discharge is by gravity. Sludge consistency is adjusted by the controlled PPM unit level set point (lower level leads to higher sludge consistency).

Attention: It is required to have PPM vat with level above the plates BEFORE FEEDING the unit, to avoid damage to the plates related to direct impact of in-coming water flow on the plates. The plate level is defined in interlocks as LOW level VALUE.

It is forbidden to empty the PPM vat by either accept valve or Flushing valves with presence of thick sludge on the PPM unit surface. The weight of the Sludge on the plates could lead to damage to the plates. The Sludge should FIRST be removed from the unit by operating without feed for a while, or temporarily in-creasing the level.

Special attention will be paid also to the possibility of leaking/passing valves, which can lead to significant level decrease during a shut. Good practice is to re-move all sludge from system on each shut by increasing PPM500 unit operating level prior to stopping PPM Feed pump. This operation may be included in Group-stop.


WARNING




Filtrate water tank 13CE07Tank 13CE07 is used to feed:

Microflotator feed pump 13PPC10 (See next paragraph describing Mi-croflotation sub-system)

Pump 13PPC19 used to transfer Loop 3 filtrates to parallel “VOITH” deinking line in case corresponding Microflotator is underused. (In that case, same clarified water flow must be transferred back to Clarified Wa-ter tank 13CE08).

Case 1: Microflotation processing Loop 3 filtratesThis tank receives all the filtrate water from DNT washer.

Tank level is monitored by controller LIC13010 acting on valve FCV-13015 on Mi-croflotator feed pump 13PPC10 delivery pipe.Thanks to this regulation, Micro-flotation flow operating is the same than Washers filtrates extraction flow.

Case 2: Microflotation processing Loop 2 filtratesWashers are not in use and this tank receives filtrates transferred from Loop 2 with pump 1PPC10.

In this case Tank level is monitored by controller LIC13010 acting on valve LCV-13010 on feed pump 10PPC10 delivery pipe.Thanks to this regulation, tank 13CE07 calls for make-up the same flow as set to Microflotator feed flow FIC13015.

Clarified water tank 13CE08This tank receives:

Clarified water accepted from Microflotator 13POS12. PM Clarified water make-up ensuring water complement to DIP line and

tank filling on start-up. Eventually clarified water from parallel “VOITH” deinking line if simultan-

eously pump 13PPC19 transfers Loop 3 filtrates from tank 13CE07 to Microflotation in parallel “VOITH” deinking line.

The level is monitored by controller LIC13005 acting on valve LCV-13005 on wa-ter complement pipe provided by PM Water filtrates.

Tank 13CE08 is used to feed: DNT washers feed pump 13PPC01 Loop 3 water dilution pump 13PPC09 Dispersing system dilution pump 13PPC18 Water pump 13PPC11 used for transfer of clarified water to Loop 2

Clear Filtrate tank 10CE06 during start-up (tank filling) or in case Micro-Flotation is fed with Loop 2 filtrates from pump 10PPC10.



1.70.3.2 Micro-flotation

Microflotators 13POS12 is fed by pump 13PPC10 at a flow controlled by Flow-meter FIC13015 (through an operator set-point or according to feed tank level controller LIC13010).

PH of feed filtrates is measured by transmitter AIR13020 and displayed/recorded.

Filling the Poseidon unit is done by opening from DCS On/Off valve AV-14050 on Fresh Water header. The filling water inlet is positioned between Accept valve & Poseidon vat; Filling water enters the Poseidon vat from the accept side, under the Poseidon plates.

Chemicals are added to help the work of Microflotator. (Chemicals flow should be adjusted in proportion with Micro-Flotation filtrate feed flow, continuously meas-ured by FIC13015):

Coagulant connected to suction of Microflotator feed pump 13PPC10. Flocculent in the pipeline feeding Microflotator (through several pipes

equipped with manual valves to be adjusted on start-up according to Micro-Flotation required efficiency).

Microflotation circulation pump 13PPC13 is recycling to Microflotator inlet a small part of clarified white water mixed with compressed air.Recirculation water pressure is continuously measured by PIS14025 and is ad-justed on start-up by manual setting of the Pressure relief valve at the end of the pressurization tube.

The Air injected into the recirculated flow can be checked in the local panel with the Air rotameter, and is adjusted in flow by intervention in the panel on the Air adjustment valve.

Opening in the field of manual valve on Vent line from pressurization tube to Pos-eidon vat allows to check the proper air content of the Pressurized filtrate recircu-lated flow. This manual vent valve should remain slightly open to avoid accumula-tion of air in the pressurization tube.

Accept clarified water from each Microflotator flow to clarified tank 13CE08.The level into Microflotator is kept constant with level controller LICS14045 and associated control valve LCV-14045 connected on clarified water outlet pipe.

The Level in the Poseidon vat is used together with Sludge Scraper speed to ad-just the thickness of the sludge mat on the top of the unit: lower operating level & lower operating speed gives thick mat, and gives higher consistency. The limit is appropriate discharge of the sludge mat.

A temporary increase in level can be used to remove all sludge from the Pos-eidon unit's surface, either by opening Filling valve or by setting accept valve to manual.

Heavy sludge settling in each Microflotator is periodically removed from the vat bottom via On/Off valves AV-14030, AV-14035 and AV-14040.



Foam is continuously removed from the surface of Microflotator by a scrapping system.

Microflotation sludge

Sludge is collected in sludge chest 13CPA14 equipped with a vertical agitator 13AG15.

Extraction pump 13PPC16 is equipped with a variable speed motor controller SC14060 in order to adapt delivery flow to sludge chest 13CPA14 level LICS14060.

Using a Prime MAC concept in Loop 1 Deinking line gives the opportunity to re-introduce a part (even the totality) of micro-flotation sludge, in order to reduce fiber losses and increase plant yield.

This re-introduction flow is adjustable through Flowmeter FIC14065 on transfer pipe to Foam tank 03CPA08, from which recirculated sludge is pump by 03PPV10 to prime Mac 03CEV02a feed pump suction.

Remaining sludge flow (subtraction of recirculation flow FIC14065 from pump 13PPC16 delivery flow) is sent to sludge treatment and controlled by pressure controller PIC14070 with control valve PCV-14070 (giving a necessary counter pressure drop for Flow control FIC14064 proper operation).

Operator checking is required to monitor sludge chest level LIC14060, and to modify if necessary recirculation flow FIC14065 set point.This will avoid setting a recirculation flow higher than sludge flow extracted from Microflotator.




Microflotator: 1 x PPM750Inlet design flow 750 m3/h at consistency 0,3%.




LIC 13005Clarified water tank 13CE08 level con-trol

10% 15% 80% 90% 0-100 m3

LIC 13010 Filtrate tank 13CE07 level control 10% 15% 80% 90% 0-100 m3

FIC 13015Microflotator 13POS12 feed flow con-trol

0-800 m3/h

AIR 13020PH indication of Microflotation feed fil-trate

5 to 11

PSL 14005Poseipump control panel air feed pres-sure

L From local panel

PIS 14025Poseipump 13PPC13 delivery pressure control

5,8 0-10 bars

FSA 20180Poseipump 13PPC13 sealing water Low flow alarm

L Digital alarm

LICS 14045 Microflotator 13POS12 level control 50% 98% 100% 0-100% level

LICS 14060 Sludge chest 13CPA14 level control 10% 15% 80% 90% 0-10 m3

SC 14060Sludge pump 13PPC16 motor speed control

0-100%

FIC 14065Flow control of Microflotation sludge transferred to Prime MAC

0-80 m3/h

FIC 14070Pressure control of Microflotation sludge transferred to treatment

0–4 Bars




291- INTERLOCKS TO LOOP 3 WATER DILUTION PUMP 13PPC09

If Clarified water tank 13CE08 level LIC13005 is Low-LowThen Loop 3 water dilution pump 13PPC09 is stopped.

If Clarified water tank 13CE08 level LIC13005 is LowThen Inhibit start of Loop 3 water dilution pump 13PPC09

292- INTERLOCKS TO DISPERSION DILUTION PUMP 13PPC18

If Clarified water tank 13CE08 level LIC13005 is Low-LowThen Dispersion dilution pump 13PPC18 is stopped.

If Clarified water tank 13CE08 level LIC13005 is LowThen Inhibit start of Dispersion dilution pump 13PPC18.

293- DISPERSION DILUTION PUMP 13PPC18 TO SLAVE VALVE AV-13025

If Dispersion dilution pump 13PPC18 is not runningThen On/Off slave valve AV-13025 is forced closed

If Dispersion dilution pump 13PPC18 is runningThen With On-Delay T=5s, Open slave valve AV-13025 (air exhaust limit

to open 15s)

294- INTERLOCKS TO TRANSFER PUMP 13PPC11 TO LOOP 2

If Clarified water tank 13CE08 level LIC13005 is Low-LowThen Transfer pump 13PPC11 is stopped.

If Clarified water tank 13CE08 level LIC13005 is LowThen Inhibit start of Transfer pump 13PPC11.

295- INTERLOCKS TO TANK 13CE07 FEED PUMP 10PPC10

While Micro-flotation is fed with Loop 2 filtratesIf Filtrate tank 13CE07 level LIC13010 is High-High

Then Feed pump 10PPC10 is stopped.And Control valve LCV-13010 is forced closed



296- INTERLOCKS TO FILTRATES TRANSFER PUMP 13PPC19

If Filtrate tank 13CE07 level LIC13010 is Low-LowThen Transfer pump 13PPC19 is stopped.

If Filtrate tank 13CE07 level LIC13010 is LowThen Inhibit start of Transfer pump 13PPC19.

297- FILTRATE TANK 13CE07 LEVEL TO MICRO-FLOTATION FEED PUMP 13PPC10

If Filtrate tank 13CE07 level LIC13010 is Low-LowThen Micro-flotation feed pump 13PPC10 is stopped.

If Filtrate tank 13CE07 level LIC13010 is LowThen Inhibit start of Micro-flotation feed pump 13PPC10.

298- INTERLOCKS FROM MICRO-FLOTATION FEED PUMP 13PPC10

If Micro-flotation feed pump 13PPC10 is not running

Then Control valve FCV-13015 (on delivery pipe) is forced closedAnd Microflotator 13POS12 level LICS14045 is disabled with valve LCV-

14045 forced closed.

If Micro-flotation feed pump 13PPC10 is runningThen With on delay T=5s, Control valve FCV-13015 (on delivery pipe) in Auto

is opened

299- INTERLOCKS TO DOSAGE OF COAGULANT & FLOCCULENT

If Poseidon Feed pump 13PPC10 is not runningOr Poseipump 13PPC13 is not runningOr Microflotation feed flow FICA3015 is Low

Then Coagulant & Flocculent dosage to Microflotation is disabled

300- SLUDGE CHEST 13CPA14 LEVEL LICS14060 TO AGITATOR 13AG15

If Sludge chest level LICS14060 is Low-LowThen Stop Agitator 13AG15

If Sludge chest level LICS14060 is LowThen Inhibit Start Agitator 13AG15



301- SLUDGE CHEST 13CPA14 LEVEL LICS14060 to EXTRACTION PUMP 13PPC16

If Sludge chest 13CPA14 level LICS14060 is LowThen Stop sludge pump 13PPC16

302- SLUDGE PUMP 13PPC16 to REGULATIONS ON DELIVERY PIPE

If Sludge transfer pump 13PPC16 is not running

Then Outlet pressure controller PIC14070 is disabled with valve PCV-14070 forced closed.

And Sludge recirculation flow controller FIC14065 is disabled with valve FCV-14065 forced closed.

303- (RESERVE)

ALARMS

304- SEALING WATER

If Loop 3 water system area is in operationAnd Main line Sealing water flow is on Alarm FSA20135 Low for T=30 s


305- COMPRESSED AIR

If Loop 3 water system area is in operationAnd Compressed Air pressure PIA19202 is on Alarm Low


306- CLARIFIED WATER TANK 13CE08 LEVEL LIC13005 LOW

If Clarified water tank 13CE08 level LIC13005 is Low




307- POSEIPUMP 13PPC13 SEALING WATER ALARM

If Poseipump 13PPC13 is runningAnd Sealing water flow FSA20180 is on Alarm Low

Then Set Poseipump 13PPC13 sealing water alarm

308- (RESERVE)



1.74 OPERATION

1.74.1 Start-up

Basic conditions:- Fresh water pump (external of the deinking line) must be running.- PM water pump (external of the deinking line) must be running.- Sealing water main line is under pressure and Flow switch FSA20135 is not


Low).- Micro-flotation Chemicals ready

Starting up Loop 3 white water clarification and distribution begins with the filling phase of the tanks and units.


If water tanks are empty (for example on first start-up), open the filling water valve LCV-13005 from PM WATER header to fill Clarified water tank 13CE08.

1.74.1.2 Start up the Microflotator

Refer to associate Function Chart separately supplied by Kadant.

1.74.1.3 Production

As soon as water tank levels are up to Low level, connected water pumps can start if required by the sub-systems.

Through interlocks, Micro-flotation area starts once filtrate come from DNT washer (or when Loop 2 filtrates are transferred with pump 10PPC10 to tank 13CE07).



1.74.2 Operation

To be monitored during the operation of the installation: Sludge and foam characteristics (no presence of fibers). Regularity of levels in Microflotators. Regularity of levels in water tanks.

1.74.3 Shutdown

In priority, refer to associated Function chart (supplied separately)

1.74.3.1 Micro-Flotation

Microflotation stops in production:- With Loop 3 when no more filtrates come from DNT washer.- Or when no more filtrates are transferred from pump 10PPC10 to tank

13CE07.

Increase the level in Poseidon to eliminate Sludge from Surface- Force set-point for LICS14045 to 99%;- Wait T=5 minutes;

Stop Feed to Poseidon- Stop Poseidon feed pump 13PPC10

(Interlocks disable controllers FIC13015 & LICS14045, Coagulant & Floccu-lent dosage)

- Wait for T=5 minutes, then proceed;

Close Air Injection (Close solenoid valve inside the pneumatic panel)

Stop Microflotation circulation pump 13PPC13.

Stop Microflotator sludge thickener & scraper drive.

1.74.3.2 Loop 3 water tanks

This stop sequence is the last one to be run on the Deinking line.

Each connected pump stops when no more required by depending sub-system.


Documents

DIP PROCESS Khanna paper