12487 Mop 22 001 a Operating Manual Clarification

OPERATING MANUAL 12487 – Bien Hoa TALODURA CALRIFICATION

This document is for the sole use of Bien Hoa only and is not to be lent, copied or reproduced in whole or in part without prior written consent of Tate & Lyle Process Technology

TALODURA CLARIFICATION

OPERATING MANUAL

TATE & LYLE PROCESS TECHNOLOGY

THAMES REFINERY

FACTORY ROAD, SILVERTOWN

LONDON E16 2EW

UNITED KINGDOM

Telephone: + 44 20 7476 4455 Facsimile: + 44 20 7540 1766 Website: http://www.tlpt.co.uk E-mail: [email protected]

Document Reference Date Prepared Checked Approved

12487-Mop-22-001 22/09/2011 N Ejikeme S Enright M Moreno

mailto:[email protected]



PLEASE NOTE FOR YOUR PERSONAL SAFETY PROCESSES IN THE SUGAR INDUSTRY HANDLE SYRUP AND VAPOURS AT HIGH TEMPERATURES AND ELEVATED PRESSURES.

IT IS IMPERATIVE THAT ALL LOCAL ENGINEERING STANDARDS, HEALTH AND SAFETY LAWS AND FACTORY REGULATIONS ARE OBEYED AT ALL TIMES TO ENSURE THE SAFE INSTALLATION AND OPERATION OF EQUIPMENT.

FAILURE TO FOLLOW THESE REGULATIONS COULD LEAD TO SERIOUS PERSONAL INJURY.

ANY PERSON HANDLING CHEMICALS SHOULD WEAR APPROPRIATE PERSONAL PROTECTIVE EQUIPMENT (PPE) AND CLOTHING.

ELECTRICAL SAFETY

HIGH ELECTRICAL VOLTAGES ARE USED WITHIN THE CONTROL SYSTEM. IF YOU DO NOT UNDERSTAND ANY OF THE INSTRUCTIONS SUPPLIED, CONTACT TATE AND LYLE PROCESS TECHNOLOGY FOR CLARIFICATION.

FOLLOW ALL WARNINGS, CAUTIONS AND INSTRUCTIONS MARKED ON AND SUPPLIED WITH THE PRODUCTS.

INFORM AND EDUCATE YOUR PERSONNEL IN THE PROPER INSTALLATION, OPERATION AND MAINTENANCE OF THE PRODUCT.

IF REPLACEMENT PARTS ARE REQUIRED, ENSURE QUALIFIED PERSONNEL USE REPLACEMENT PARTS SPECIFIED IN THE CONTRACT FROM TATE AND LYLE PROCESS TECHNOLOGY.

UNAUTHORISED PARTS AND PROCEDURES CAN EFFECT THE PRODUCT’S PERFORMANCE AND PLACE THE SAFE OPERATION OF YOUR PROCESS AT RISK.

LOOKALIKE SUBSTITUTIONS MAY RESULT IN FIRE, ELECTRICAL HAZARDS, OR IMPROPER OPERATION.

ENSURE THAT ALL EQUIPMENT DOORS ARE CLOSED AND PROTECTIVE COVERS ARE IN PLACE, EXCEPT WHEN MAINTENANCE IS BEING PERFORMED BY QUALIFIED PERSONNEL, TO PREVENT ELECTRICAL SHOCK AND PERSONAL INJURY.

VESSEL ENTRY

BEFORE ENTERING ANY VESSELS IT MUST FIRST BE INSPECTED BY THE LOCAL SAFETY OFFICER AND A PERMIT TO ENTER MUST BE ISSUED AS LAID DOWN BY LOCAL REGULATIONS.

ANY ISOLATED VESSEL WHICH CONTAINS / HAS CONTAINED LOW BRIX SUGAR SYRUPS CAN GENERATE AN UNBREATHABLE ATMOSPHERE WITHIN 24 HOURS.

ENSURE ALL VESSELS ARE THOROUGHLY WASHED AND VENTILATED BEFORE ENTRY.

DO NOT ENTER UNLESS YOU KNOW IT IS SAFE!

PLEASE NOTE - ALLOWANCES FOR SEISMIC CONDITIONS HAVE NOT BEEN MADE



CONTENTS

SECTION 1 GENERAL 4

SECTION 2 PROCESS DESCRIPTION 5

SECTION 3 CONTROL SYSTEM 5

SECTION 4 PROCESS OPERATION 17

SECTION 5 FAULT FINDING 22

SECTION 6 DOSING CALCULATIONS 28

SECTION 7 APPENDIX 31



SECTION 1 GENERAL

1.1 Introduction

This manual is designed to assist the operating staff in understanding the parameters and operation of the Talodura Clarification process in order to achieve optimum performance.

An experienced TLPT Engineer shall give comprehensive training with respect to process operations during plant commissioning.

IF YOU DO NOT UNDERSTAND ASK!!!

1.2 Manual Operation Warning

Extreme caution should be used when any element is selected in manual as there is no input from the control system.

The process is designed to operate in automatic sequences. In manual unpredictable effects will occur, resulting in poorer quality product, damage to pumps, tanks overflowing etc.

As manual operation bypasses process interlocks it should only be used during commissioning and fault finding exercises by trained and competent personnel.



SECTION 2 PROCESS DESCRIPTION

2.1 Overview

This section should be read in conjunction with the relevant Piping & Instrumentation Diagram (PID). Please refer to Section 7, Appendix section 7.1.

The purpose of the Talodura clarification process is to remove colour and turbidity from the syrup by means of a flocculation/flotation separation technique. It's a continuous process and comprises of five steps:

a) Creation of primary floc of calcium phosphate precipitates which adsorbs colloidal and coloured material to its surface. This process is pH sensitive.

b) The aggregation of these flocs to a size such that, given non-turbulent conditions, the aeration mentioned in (c) and sufficient time in a clarifier, their buoyancy will cause them to rise to the surface of the syrup. If additional decolourisation is required, the floc formation can be enhanced and aggregation improved by the addition of a proprietary decolourant (TALOMEL). These first two steps are carried out in a reaction tank.

c) The addition of tiny air bubbles in the aeration tank which attach themselves to the flocs as an aid to flotation;

d) The addition of flocculant, to the inlet pipe to the clarifiers, to create large flocs with the air trapped within them to aid floatation.

2.2 Process Flow

Evaporated syrup is fed into the Untreated Syrup Buffer Tank TK2201 where it is continuously mixed by the agitator.

The level in the tank is measured by a level transmitter 22LT001.

The syrup is pumped using PU2203A/B from TK2201 into the reaction tank TK2205 via a flow control system and plate heat exchangers HE2204A/B. The reaction tank and clarifier system is designed to handle 47 m3/hr flowrate. If the HE 2204A is blocked then HE2204B can be used by altering the appropriate manual valves. The flow is measured by magnetic flowmeter 22FT005. This is displayed as m3/hour and tonnes of syrup solids per hour (TSSH). The flow is controlled by modulating the flow control valve 22FCV005. The syrup

temperature is usually controlled at 85C by regulating a supply of indirect heating steam to the plate heater.

The reaction tank TK2205 has two chemical reaction compartments and an aeration compartment with one outlet. Syrup, phosphoric acid and lime sucrate are fed into the first section of TK2205 and complete mixing of the chemicals is ensured by the two reaction tank agitators AG2206 and AG2207.



The reaction tank has a set of dosing pumps. The phosphoric acid is dosed by metering pump PU2244, the speed of which is automatically controlled proportional to syrup flow rate and dosage (ratio) setting.

Lime sucrate is dosed into TK2205 reaction/aeration tank by PU2239 dosing pump. There is a lime sucrate trim control which can adjust the speed by + or – 15%.

Both chemicals are added through flexible hoses feeding into a tundish so that at any time the real quantity of chemical being added can be checked against the calculated amount. This is in order to monitor dosing pump performance.

The reaction of phosphoric acid and lime sucrate produces a calcium phosphate precipitate (primary floc) which adsorbs colloidal and coloured material to its surface.

A decolourising agent is added to the buffer tank if additional decolourisation is required. The speed of PU2246 decolourising dosing pumps is a direct proportion of the flow rate and dosage set point.

The syrup then flows over a weir plate to the aeration compartment, where it is aerated by AG2208 Cavitation Aerator. From the aeration compartment the syrup flows by gravity to the clarifiers. Talodura flocculant is dosed in-line between the aeration compartments and the clarifier by the flocculant dosing pump PU2235, the speed of which is automatically proportional to syrup flow rate and dosage (ratio) setting.

The pipes and valves between the aeration compartment and the clarifier are configured so that the clarifier can be taken off line when required.

As the syrup enters the large central tube of the clarifier the flocculant is gently stirred into the syrup by the gate stirrer AG 2212. The syrup then overflows into the body of the clarifier. The primary flocs and finely dispersed air are coagulated by the flocculant solution to form large aerated flocs that float to the surface of the clarifiers forming a scum layer. The scum is removed from the surface by a variable speed scum rake AG2213 and is discharged into the clarifier’s peripheral scum trough from where it flows by gravity. The clarified syrup flowing down to the bottom of the clarifier enters the outlet ring main and rises up to the weirbox. The weirbox setting is adjustable and is used to vary the liquid level in the clarifiers according to the nature and quantity of the scum being formed. These controls enable the depth and consistency of the scum layer to be varied as required to obtain the best results.

From the weirbox the clarified syrup flows into the Clarified Syrup Tank TK2220. During start up, or when the syrup is not fully clarified, the syrup from the weirbox can be recycled to the Untreated Syrup Buffer Tank TK2201.

The success of the process depends upon the following:-

a) As in all continuous processes, it is absolutely essential that steady-state conditions are maintained in the clarifier. Widely fluctuating brix, temperature and flow-rates will lead to poor clarification.

b) The adsorption of the colloidal and suspended matter by the calcium phosphate formed in the reaction between phosphoric acid and lime sucrate.

c) The establishment of the optimum dosage of acid. Use of good quality lime (> 65 % CaO availability) is extremely important.



d) Good aeration of the primary calcium phosphate flocs and formation of larger aerated flocs by the addition of TALODURA flocculant.

e) Sufficient time in the clarifier to allow the aerated flocs to separate from the Syrup.

f) Controlled removal of scum.

2.3 Chemical Preparation

One of the key aspects of good clarification performance is the procurement and preparation of good quality chemicals. These chemicals include;

Phosphoric acid: Food grade, 85% H3PO4 supplied as a liquid.

De-colourising Agent: Talomel, supplied as a liquid in Kg’s.

Lime Sucrate: Prepared from untreated syrup, milk-of-lime and cold water.

Flocculant Solution: Prepared from Talodura powder and High Quality Cold Water

The phosphoric acid and Talodura require no preparation as they are supplied in ready-to-use containers. The level in these chemical tanks must be regularly checked and topped up when necessary

The lime sucrate and flocculant solution require an operator to prepare fresh batches of each chemical in good time to replenish the chemical holding tank. Care must be taken deciding when to start the preparation of each chemical as they must be aged differently.

2.3.1 Phosphoric Acid

This should be 85%, chemically pure, food-grade phosphoric acid will be stored in a 316 stainless steel tank TK2243 which has a capacity of 365 litres. The acid may seriously corrode any other type of stainless steel. If an inferior grade of acid is used, the impurities it contains may accelerate the corrosive effect on the plant and associated equipment.

2.3.2 Decolourising Agent

The TALOMEL chemical is normally supplied in drums and at ambient temperature is in the liquid form. It is manually transferred directly from the drum into TK2245 holding tank. Tank capacity is 365 litres.

2.3.3 Flocculant Solution

Flocculant is prepared as a 0.1% solution i.e.: 1kg of flocculant is required for 1m3 of water.

In order to maintain its charge density and floc - forming properties it is important that the cold

condensate or softened process-water is at a temperature less than 40C and maximum conductivity of 100 microSiemens/cm.



2.3.3.1 Method of Preparation

a) When TK2231 flocculant preparation tank has been emptied, close the V22136 drain and V22137 isolation valves.

b) Open V22134 cold-water valve and start to fill.

c) Weigh out the required weight of flocculant powder.

d) When the tank is half full, shut V22134 water valve and open V22133 air valve to give vigorous agitation to the tank.

e) Open V22135 valve so that water “vortex” to halfway up the wetting cone of the educator.

f) Pour the flocculant into the funnel of the eductor.

g) Switch on the eductor and adjust the controller until a steady amount of flocculant vibrates down the channel into the tank. The flocculant should be fed approximately 400 grams of powder every minute.

h) When all the powder has been added, shut V22135 cold-water valve and switch off the educator.

i) Re-open V22134 water valve until the level rises to the full mark.

j) Reduce V22133 air valve to give gentle agitation for 60 minutes.

k) Close V22133 air valve and leave the solution to mature for 60 minutes.

l) When TK2234 is almost empty, open V22137 isolation valve and drain to TK2234.

m) Wash out TK2231 preparation tank with cold water to drain.

NOTE: Flocculant molecules will be sheared if the solution is passed through partially open valves. Always ensure in-line valves are fully open when in use.

Flocculant solution will become ineffective after 18hours so fresh solution must be prepared after a long process stoppage.

Due to the maturation period for flocculant solutions and the time needed for powder addition, the preparation procedure should be started approximately 6 hours before the flocculant is required.

2.3.4 Lime Sucrate

Milk-of-lime, untreated syrup and cold water are mixed together to form a solution of lime sucrate. The following volumetric quantities of chemicals should be used;

The working volume of TK2236 preparation tank is 5.5 m3

50% (2.75 m³) Unclarified syrup (60°Bx)

25% (1.375 m³) 10° Baume milk-of-lime (94 grams of CaO/litre)

25% (1.375 m³) Cold water



2.3.4.1 Method of Preparation

a) Clean out TK2236 preparation tank, using cold water, drain and close V22145 drain and V22146 isolation valves.

b) Open V22144 evaporated syrup valve and add the required amount.

c) Start AG 2237 lime sucrate agitator.

d) Open V22143 milk of lime valve and add the required amount.

e) Open V22142 water valve and add the required amount.

f) Continue stirring for 60 minutes.

g) Stop AG 2237 lime sucrate agitator and leave to settle for 2 hours.

h) When TK2238 lime sucrate holding tank is almost empty, open V22146 outlet valve and transfer the contents of TK2236 preparation tank into TK2238 holding tank.

i) Immediately wash out TK2236 preparation tank with water, drain & start to prepare a new batch of lime sucrate.

NOTE:

Fresh, good quality lime free from lumps, stones, straw, etc must be used to prepare the lime sucrate in order to give good pH control.

Due to the required maturation period for Lime Sucrate, this procedure should be started as soon as the preparation tank has been emptied into the Lime Sucrate holding tank. The longer the Lime Sucrate can age in the preparation tank, the better the pH



SECTION 3 CONTROL SYSTEM

3.1 Introduction

The control system is described in the Control System manual.

General navigation around the screens can be achieved by clicking on the desired icon or screen links.

3.2 Screen Icons

3.2.1 Pump/Motor Icons

The icons are:

Pump/Motor Running Pump/Motor Faulty Pump/Motor Stopped

“M” refers to manual mode, if auto “A” would be displayed.

Touch the icon and either of the following faceplate is displayed.

Duplex Pump/Motor Single Pump/Motor

The functions of the buttons are: START The pump/motor will start, if in manual mode.

STOP The pump/motor will stop, if in manual mode.

AUTO The pump/motor is in Auto mode, started and stopped from the PLC.

DUTYA If selected pump/motor A is operating.

DUTYB If selected pump/motor B is operating.

MAN The pump/motor is in manual mode and can be started and stopped by the operator using above start and stop buttons.



RESET Reset fault condition.

EXIT Display disappears.

When touched they are highlighted green.

If the pump is a dosing pump the following additional icon could be displayed.

Lime Sucrate Flocculant, Acid or De Colourisation

The functions of the additional buttons are:

START The dosing pump will start, if in manual mode.

STOP The dosing pump will stop, if in manual mode.

AUTO The dosing pump is in Auto mode, started and stopped from the PLC.

MAN The dosing pump is in manual mode and can be started and stopped by the operator using above start and stop buttons.


Lime Sucrate pump

SPEED The speed can be entered by the operator, if in manual mode.

Flocculant, Acid or De Colourisation pumps

PPM The dosing rate is entered by the operator

SPEED The speed of the motor is displayed.



3.2.2 Agitator Icon

The agitator icons are:

Agitator Running Agitator Stopped

3.2.3 Scraper Drive Icons

The scraper drive icons are:

Scraper Running Scraper Faulty Scraper Stopped

Touch the icon a keypad is displayed and the speed can be entered.

3.2.4 Valve Automatic On/Off

The valve icons are:

Valve Open Valve Faulty Valve Closed

Touch the icon and the following typical faceplate is displayed

The functions of these buttons are:

OPEN The valve will open if in manual mode.



CLOSE The valve will close if in manual mode.

AUTO The valve is in Auto mode, opened and closed from the PLC.

MAN The valve is in manual mode and can be opened and closed by the operator using above open and close buttons.


EXIT Display disappears.

When touched they are highlighted green.

3.2.5 Valve Control

The icon is:

The amount of green inside the valve indicates the percentage the valve is open.

Touch the icon and the following typical faceplate is displayed

The functions are:

PV Process Variable.

SP Set point entered by the operator.

CV Percentage output to the control valve.

AUTO Automatic PID, controlling to the SP.

MAN The position of the valve can be entered by the operator.

EXIT Display disappears



3.2.6 PID Setting icon

The icon is:

This is displayed only if an Engineer logs in, refer to Control System manual.

Touch the “GAIN” or “INT s” or “DER’s” icons, a keypad is displayed and the parameter value can be entered.

EXIT Display disappears

3.2.7 Process Parameters Displayed

The units of the various process parameters displayed are

Current amps.

Flow m3/hr and or TSSH.

Level percentage of maximum level.

Pressure gauge barg.

Pressure absolute bar.

Temperature oC.

3.2.8 Switches Icon

These can be level, pressure and will show Red if made or tripped.

3.3 HMI Maintenance

The HMI device is designed for maintenance-free operation. The touch screen and keyboard membrane should nevertheless be cleaned regularly.

Use a cleaning cloth dampened with a cleaning agent to clean the equipment.

3.3.1 Procedure

Proceed as follows:

1. Press the “Cleaning Button”.

2. Spray the cleaning solution onto a cleaning cloth. Do not spray directly onto the HMI device.



3. Clean the HMI device.

When cleaning the display wipe from the screen edge inwards.

3.3.2 Caution

Do not clean the HMI device with compressed air or steam jet blowers. Never use aggressive solvents or scouring powder.

3.4 Process Trends

The screen below is a typical process trends, the actual parameters displayed will depend on the process.

The control system displays data for Buffer tank level, flow & pH as a graphical chart.

Move Trend display backward



Move Trend display forward

Changes Scale

The other buttons are not used.

Note: The trends for flow are scaled on the chart at 0–100% of their respective maximum setpoints. The actual current values are shown in the corresponding displays at the bottom of the screen

3.5 Alarms Screen

The screen below is a typical process alarms, the actual alarms displayed will depend on the process.

Press the Alarm Page button to display active and unacknowledged alarms.

Acknowledge alarm button, Silences external sounder.

Active alarms Displayed in red.

Acknowledged Active alarms Displayed in Yellow.

Unacknowledged cleared alarms Displayed in green.

Acknowledged cleared alarms Deleted from the alarm page.

To exit press Alarm page button or the x at the top right of the alarm page



SECTION 4 PROCESS OPERATION

4.1 Operator Screens

The following screens are used to control the Clarification process.

General navigation around the screens can be achieved by touching either the relevant button or desired icon on the current screen. Please refer to Section 3 for screen navigation instructions.

For trends and alarms refer to Section 3.

The process is both monitored and controlled from the control system but for efficient operation of the process the client must organize the following:

a) Routine observations of the process (refer to section 4.3)

b) Laboratory analysis of the process, i.e. measurement of brix, pH and turbidity.



4.2 Process Start up Procedure

Below procedures are described for reaction tank TK 2205.The syrup is pumped from PU2203 via HE 2204A.

4.1.1 Process Start up Procedure- with process tanks empty

a) Check that Phosphoric Acid Tank TK2243 and Talomel Tank TK2245 are full. Prepare a full tank of milk-of-lime. Prepare fresh chemicals for Lime Sucrate Tank TK 2238 and Flocculant Tank TK2234. Allow aging time (Refer section 2.3)

b) Lower weir for the clarifier TK 2211 to its lowest setting. Enter the dosing rate set-points for flocculant, phosphoric acid and decolourising agent in parts per million (ppm). (Refer section 7)

c) Check that all the associated manual process valves are open (refer to PID). Check steam header isolation valve is shut. Open isolating valves on the selected chemical dosing pumps.

NOTE: Check and re-confirm required manual valves are opened for the heat exchangers taken on duty prior to the start of the process. Refer to Section 7- Appendix for valve configuration for each of the reaction tanks.

d) When the level in the buffer tank TK2201 is 30% or above, start buffer tank agitator AG2202

e) When the level in the buffer tank TK2201 is 60% or above, set the syrup flow control 22FCV005 to manual - opening = 20%

f) Select syrup feed pump PU2203A and open suction valve V22003. Start pump and open discharge valve V22009.

g) Open heat exchanger isolation valves. When operator confirms syrup is entering reaction tank TK2205, open steam isolating valve.

h) Set flow control to auto at SP = “required value”

i) Set temperature control to auto at SP = 87oC

j) Start phosphoric acid auto dosing – pump PU2244

k) Start manual lime sucrate dosing – pump PU2239

l) When operator confirms syrup is cascading over weir into 2nd reaction tank compartment; start first reaction tank agitator AG2206

m) When operator confirms syrup is cascading over weir into aeration compartments then; start second reaction tank agitator AG2207

n) When operator confirms syrup is cascading over flocculating chamber of clarifiers TK2211 start cavitation aerator - AG2208

o) Start auto flocculant dosing – pump PU2235

p) Start clarifier gate stirrers - AG2212

q) When operator confirms clarifiers TK2211 are full, start clarifier scrapers - AG2213.



r) When the scum level approaches the clarifier rim, use the hand-wheel to adjust the weirbox height and achieve the correct scum thickness (150 to 200 mm). Adjust the speed of the scraper drive to give one revolution approximately every 120 seconds.

s) Open V22050 manually and the syrup will recycle back to buffer tank TK2201 provided V22051 is closed.

t) When operator confirms that the syrup is “clear”, valve V22050 is opened BEFORE valve V22051 is closed.

u) The operator should initiate auto level control for buffer tank TK2201.

4.1.2 Process Start Up Procedure - Process Tanks Full

a) Check that phosphoric acid tank TK2243, lime sucrate tank TK 2238, flocculant tank TK2234 and Talomel tank TK2245 levels are greater than 20%.

b) Wait until the level in the buffer tank TK2201 is 50% or above then;

c) Set flow control to manual - valve opening = 20%

d) Start feed pump - PU2203 A or B

e) Wait 10 seconds

f) Set flow control to auto at SP = “required value”

g) Set temperature control to auto at SP = 87oC

h) Start phosphoric acid auto dosing PU2244

i) Start auto flocculant dosing PU2235

j) Start first reaction tank agitator AG2206

k) Start second reaction tank agitator AG2207

l) Start cavitation aerator AG2208

m) Start clarifier gate stirrer AG2212

n) Start clarifier scraper AG2213

o) Syrup will recycle back to buffer tank TK2201 provided the operator has opened manual valve V22050 and closed valve V22051.

p) When operator confirms that the syrup is “clear”, valve V22051 is opened BEFORE valve V22050 is closed.

q) The operator should initiate level control for buffer tank TK2201.

4.3 Process Shut Down

4.2.1 Process Shut Down - Short-Term

If a short-term shut down of less than one hour is required, the operator will put the system into manual recycle mode. Valve V22050 is opened and valve V22051 is closed. The decolourant dosing pump should be stopped.



If the shut down is prolonged for a longer period the following sequence should be followed.

a) Set temperature control to manual and valve opening to 0%

b) Set flow control to manual and valve opening to 0%

c) Stop feed pump PU2203

d) Stop phosphoric acid pump PU2244

e) Stop lime sucrate pump PU2239

f) Stop flocculant pump PU2235

g) Stop first reaction tank agitator AG2206

h) Stop second reaction tank agitator AG2207

i) Stop cavitation aerator AG2208

j) Stop clarifier gate stirrer AG2212

k) Stop clarifier scraper AG2212

l) When the level in the buffer tank TK2201 is 30% or below stop buffer tank agitator AG2202

4.2.2 Process Shut Down – Long Term

A few hours prior to a planned shut down, the level of the Mixed Juice Tank should be lowered as much as possible in order to accommodate the scum from the main clarifiers during liquidation. The clarifier weirs should be raised so as to remove the scum from the top of the clarifiers and maintain as thin a scum bed as possible without loss of syrup. The purpose of this procedure is to reduce any potential sugar loss.

Once the buffer tank TK2201 is empty and no further syrup is available:

a) Stop syrup feed pump PU2203 and set the flow control to manual at 0%.

b) Stop buffer tank agitator and all chemical dosing pumps.

c) Fill buffer tank TK2201 with hot process water via manual valve V22005.

d) Set flow control to desired flow rate.

e) Start feed pump PU2203 and chemical dosing pumps.

f) Continue pumping water through both the reaction systems and remove as much scum as possible from top of the clarifiers

g) When brix in the flocculation chambers is low (0 to 2°Bx), close steam isolating valve and set the temperature flow control to 0%.

h) Stop dosing pumps & feed pump PU2203.

i) Stop agitators AG2202, 2206, 2207, 2208, 2212 and 2213.

j) Lower the clarifier weir as much as possible.

k) Open clarifier drain valve V22052 so that as much syrup as possible goes forward to the process.



l) Open drain valve V22047. Send the remaining syrup and scum to the scum feed tank, taking care to ensure that this tank does not overflow.

m) Wash out the clarifiers and run washings into scum holding tank.

n) Open valves V22044, V22045, V22046, V22120 and V22049 to drain the contents of the reaction tanks and flocculation chambers to the buffer tank TK2201. Wash out these tanks with water.

o) Open the buffer tank drain valve V22001 and allow contents to drain to sewer.

p) Open valves V22138 to drain the flocculant tank as flocculant will be ineffective after a prolonged stop. Wash out tanks to drain.

q) Close all drain and liquidating valves.



SECTION 5 FAULT FINDING

This section attempts to aid an operator solve process problems encountered during the operation of the process.

5.1 Syrup flowrate is reading “Low”

A manual valve may be closed in line

Check all manual valves between the Buffer Tank (TK2201) and the Reaction tank (TK2205).

Feed pump speed control not operating correctly.

Check the Motor speed control mode of operation (auto/manual) and setpoint from HMI.

Check motor speed against manual setpoints.

Check flow-meter bypass valve is 100% closed

Syrup feed pump is “air-locked”, Check the feed pump ammeter for a ‘low’ reading. If so, purge the pump casing of air.

Syrup feed pump fault, Check the feed pump thoroughly. If work is required on the pump switch to the standby feed pump.

Flow reading on HMI low, Check flow-meter converter display, refer to Control Systems Manual.

5.2 Syrup flowrate is reading “High” or will not decrease

Feed Pump speed too high Check the Motor speed control mode of operation

(auto/manual) and setpoint from HMI.

Check motor speed against manual setpoints.

Flow reading on HMI high, Check flow-meter converter display, refer to Control Systems Manual.

5.3 Temperature is “Low”

Heat exchanger is “air-locked” Carefully bleed air from the air vents located on

the top of the heat exchanger.

Warning – Hot liquor will leak from these vents during the air bleed. Take all necessary precautions to avoid personnel contact with liquor.



Heat exchanger is full of condensate. Carefully drain condensate from the drain valves located in the bottom of the heat exchanger.

Steam control valve not operating properly.

Check electrical/pneumatic connections to the control valve.

Check the temperature valve mode of operation (auto/manual) and setpoint from HMI.

Check control-valve position against manual setpoints.

Steam trap fault. Check steam trap is functioning properly.

If work is required, partially open the bypass valve and isolate the trap before starting work.

Insufficient steam pressure. Check steam supply pressure and temperature.

Check all manual isolation valves in the steam supply line.

5.4 Temperature is “High” or will not decrease

Steam control valve not operating properly.

Check electrical/pneumatic connections to the control valve.

Check the temperature valve mode of operation (auto/manual) and setpoint from HMI.

Check control-valve position against manual setpoints.

Steam trap fault. Check steam trap is functioning properly.

If work is required, partially open the bypass valve and isolate the trap before starting work.

Bypass valve for control valve is open. Check manual bypass valve for the temperature control valve) is fully closed.

Temperature Transmitter fault. Check transmitted temperature against the temperature gauge

Check transmitter calibration (span and zero).

Check transmitter output signal.



5.5 pH reading is Low

Lime Sucrate is not being dosed, Check LS dosing pump mode of operation (LSAuto/Manual) and dosing setpoint from HMI.

Check manual isolation valves for LS dosing pumps.

Check level of LS in holding tank (TK 2238).

Check LS dosing pump thoroughly. If work is required on the pump switch to the standby dosing pump.

Lime Sucrate is too weak,

Check the lime content of the Milk-of-Lime (laboratory test).

Check the proportions of syrup, water and milk-of-lime used for LS preparation.

Check the time allowed for the LS to age.

Too much Phosphoric Acid being added,

Check acid dosing pump mode of operation (Auto /Manual) and dosing setpoint from HMI.

Check the strength of acid in use and the %H3PO4 entered in the HMI.

5.6 pH Reading is High

Phosphoric Acid is not being dosed, Check acid dosing pump mode of operation (Auto/Manual) and dosing setpoint from HMI.

Check manual isolation valves for acid dosing pumps.

Check level of acid in holding tank.

Check acid-dosing pump thoroughly. If work is required on the pump switch to the standby dosing pump.

Warning – 85% Phosphoric Acid is very corrosive!. Take all necessary precautions to avoid personnel contact with acid.

Lime Sucrate is too strong,

Check the lime content of the Milk-of-Lime (laboratory test).

Check the proportions of syrup, water and milk-of-lime used for LS preparation.

Check the time allowed for the LS to age.



Too little Phosphoric Acid being added,

Check acid dosing pump mode of operation (Auto /Manual) and dosing setpoint from HMI.

Check the strength of acid in use and the %H3PO4 entered in the HMI.

5.7 Dosing Pump not dosing

No chemicals in holding tank(s) Check levels of chemicals in holding tank.

Prepare fresh chemicals (if required) and fill holding tanks.

Dosing pump not running Check acid dosing pump mode of operation (Auto /Manual) and dosing setpoint from HMI.

Check manual pump isolation valves.

Check the electrical connections between the console and pump motors.

Check inverter drives and circuit breakers.

Check dosing pump thoroughly. If work is required on the pump, switch to the standby dosing pump.

5.8 Poor Syrup aeration

Air nipple blocked on shaft of aerator. Isolate the cavitation aerator motor and check

air nipple. Carefully wash with hot water if required.

Incorrect direction of rotation. Check the direction of rotation as displayed on the cavitation aerator gearbox housing.

Shutdown Talomel process, drain and wash out the reaction tank. Check the direction of the cavitation aerator tips.

Cavitation aerator fault. Check the local stop/start buttons.

Check the electrical connections between the agitator, stop/start panel and MCC.



5.9 Scum or Floc Carryover Into the Clarifier Eirbox

Weir level too low causing thick scum layer / floc de-aeration.

Check weirbox level and scum layer thickness. Increase the weir level to maintain a scum thickness of 15 to 20cm.

Poor aeration Check the cavitation aerator is operating correctly.

Lack of flocculant Check flocculant dosing pump mode of operation (Auto /Manual) and dosing setpoint from HMI. Increase dosing rate if possible.

Check flocculant solution strength in HMI.

Wrong pH (usually too low) Sample and test the Syrup pH in the Reaction Tank (laboratory test).

Wrong Brix (usually too high) Sample and test the Syrup brix in the Reaction Tank (laboratory test).

5.10 No Floc Formation

Lack of Phosphoric Acid Check acid dosing pump mode of operation

(Auto /Manual) and dosing setpoint from HMI. Increase dosing rate if possible.

Check %H3PO4 acid strength in HMI.

Check manual pump isolation valves.

Check level in Phosphoric acid tank.

Check the electrical connections between the PLC and pump motors.

Lack of Lime Sucrate Check LS dosing pump mode of operation (LSAuto/Manual) and dosing setpoint from HMI.

Check manual isolation valves for LS dosing pumps.

Check level of LS in holding tank.

Check LS dosing pump thoroughly. If work is required on the pump, switch to the standby dosing pump.



5.11 “Syrup-like” Scum

Lack of Phosphoric Acid Refer to 5.10

Lack of Lime Sucrate

Refer to 5.10

Lack of Flocculant

Refer to 5.10

Poor Aeration Refer to 5.8



SECTION 6 DOSING CALCULATIONS

6.1 Process Specification

REFINERY CAPACITY

Normal Solids Rate:

hour

solidssugar tonnes 31

Maximum Solids Rate:

hour

solidssugar tonnes 36%115

hour

tonnes 13

TALODURA FEEDSTOCK

Syrup Brix: 60 °Bx

Syrup Temperature: 65 °C

Syrup Density: 1.26 kg/m³

Normal Feed-rate:

hr

m

m

tonneBx

hr

tss3

3

41

26.1 60

100 31

Maximum Feed-rate:

hr

m

m

tonneBx

hr

tss3

3

47

26.1 60

100 63

Product: Clarified Syrup of a lower colour and turbidity for forward feed.

By Product: 1.4 m3/hr of calcium phosphate scum

6.2 Phosphoric Acid

Normal dosage rate of between 300 - 400 ppm of P2O5 on sugar solids is used.

Therefore, assuming a typical value of 400 ppm when using 85% chemically pure acid, the normal consumption is given by;

hour

OPkg 52

62.14ppm

10

400

tonne

kg 1000

hour

tss 6.35



hour

POHkg

OPkg

POHkg

hour

OPkg

43

52

43

52

1.23

614.0

14.2

litre/hour 7.13

1689

100023.1

3

43

3

43

m

POHkg

m

litre

hour

POHkg

Therefore, based on the above calculations, the consumption of 85% Phosphoric Acid at maximum process throughput will be 13.7 litres/hr.

6.3 Lime Sucrate

The solution is prepared by mixing milk-of-lime (M.O.L.) with untreated syrup and water to form lime sucrate. This solution is used to react with the phosphoric acid and correct the syrup pH.

Assuming,

(a) M.O.L. is available as a 10°Baume solution,

(b) 50% unclarified syrup at 60 °Brix,

(c) 25% M.O.L. at 10 °Baume,

(d) 25% cold water.

From stoichiometric calculations, 1kg of P2O5 requires 1.2 kg of CaO to maintain reaction/pH balance. Assuming an acid dosing rate of 400ppm P2O5, the mass flow of phosphate is 14.2 kg/hr (P2O5). Therefore the CaO required is;

hr

CaOkg

OPkg

CaOkg

hr

OPkg172.12.14

52

52

Milk-of-lime at 10°Baume has a CaO concentration of 94g (CaO)/litre. To calculate the volume of milk-of-lime required;

hr

litre

CaOkg

litre

hr

CaOkg181

94

100017

As Milk-of-lime is only 25% by volume of Lime Sucrate solution then the total to be pumped is;



min

(12

72425

100181

eLimeSucratlitres

hr

eLimeSucratlitre

MOLparts

eLimeSucratparts

hr

MOLlitre

Therefore, based on the above calculations, the consumption of Lime Sucrate solution at maximum process throughput is 724 litres/hour.

6.4 Flocculant

Typical dosage rates of between 10 to 15ppm of TALODURA flocculant powder on sugar solids are used in the Talodura process and 1 to 2ppm per stage of the three-stage scum de-sweetening. Therefore, using a typical dosage rate of 15 ppm, the TALODURA demand is:

hour

FLOCCULANTkg 534.0ppm

10

15

tonne

kg 1000

hour

tss35.6

6

Since Flocculant is prepared as 0.1% solution;

hour

FLOCCULANTlitres

hour

FLOCCULANTkg %1.0 534

1.0

100 534.0

Therefore, the Flocculant solution dosing rate is 534 litres/hour at maximum process throughput.

6.5 Decolourising Agent TALOMEL

The normal dosage rate for TALOMEL decolourising agent is between 100 to 300ppm on sugar solids. Therefore, using a typical dosing rate of 300 ppm, and a TALOMEL SG of 1.16, the consumption will be;

hour

TALOFLOCkg 7.10ppm

10

300

tonne

kg 1000

hour

tss 5.63

6

hour

TALOFLOClitres

kg

litre

hour

TALOFLOCkg 8.9

1160

1000 10.7

Therefore, the TALOMEL solution dosing rate is 9.8litres/hour at maximum process throughput.



SECTION 7 APPENDIX

7.1 Drawings

The following drawings are referred to in this manual

12487- PID-22-001 CHEMICAL PREPARATION TALODURA PROCESS – SIZE 6

12487- PID-22-003/4 CLARIFICATION TALODURA PROCESS – SIZE 6

7.2 Process Set-Up Parameters

Parameter Indicative

Values

Talodura Alarm Page:

Levels

Buffer Tank Low Low Level Alarm – Stops Pump

5

Buffer Tank High Level Alarm – Stop Untreated Syrup Feed.

80 %

Buffer Tank Low Level – Start TK2211recycle 30 %

Buffer Tank Level – Resume forward flow of TK 2211

50 %

LS Preparation

Minimum level for LS prep set point 0 %

MOL addition level set-point 25 %

Cold water addition set-point 25 %

Syrup addition set-point 50 %

LS Holding tank – Low level set-point 0 %

LS Holding tank- High Level set-point 100%

Dosing Parameters

Phosphoric Acid Dosing Rate 400 PPM

Talomel Dosing Rate 300 PPM

Flocculant Dosing Rate 15 PPM



Chemical Concentrations

Phosphoric Acid Strength 85 wt%

Flocculant Solution Strength 0.1 wt%

Talomel SG 1.16

7.3 Dossing pupms set up

Setpoint Description Value at

Commissioning

Flocculant Pump Maximum Flow Litres/Minute : Calibration value for PU2235. The flowrate is physically measured. This exercise is to be carried out initially during the commissioning phase under the supervision of the TLPT Engineers and should then be used after as a routine dosing pump maintenance check (every 1 week).

Decol Pump Maximum Flow Litres/Minute : Calibration value for PU2246 The flowrate is physically measured. This exercise is to be carried out initially during the commissioning phase under the supervision of the TLPT Engineers and should then be used after as a routine dosing pump maintenance check (every 1 week).

Acid Pump Maximum Flow Litres/Minute : Calibration value for PU2244. The flowrate is physically measured. This exercise is to be carried out initially during the commissioning phase under the supervision of the TLPT Engineers and should then be used after as a routine dosing pump maintenance check (every 1 week).

Lime Sucrate Pump Maximum Flow Litres/Minute : Calibration value for PU2239. The flowrate is physically measured. This exercise is to be carried out initially during the commissioning phase under the supervision of the TLPT Engineers and should then be used after as a routine dosing pump maintenance check (every 1 week).

Documents

12487 Mop 22 001 a Operating Manual Clarification