CW Pump efficiency improvement through polymer coatingindianpowerstations.org/IPS 2013 Presentations/Day-1 at Maneksha… · 3. Normal Operation Nos. 3 4, Location of Pumps CW Pump

DURGAPUR

CW Pump efficiency improvement

through polymer coating

Author

Tapan Nandy

Sr. Manager

IPS 2013

DURGAPUR

NSPCL- An Overview

NSPCL is a joint venture company of SAIL and NTPC

formed in 04th June,2002.

DURGAPUR

Unit Dates:

Synchronization Commercial Operation

Full load achieved

I 17-Feb-1987 01-Jun-1987 03-Aug-1987

II 12-Mar-1988 04-May-1988 04-May-1988

MILESTONES of NSPCL, Durgapur

Boiler : 260 T/Hr x 2

TG : 60 MW x 2

DURGAPUR

66

9

67

7

77

0

90

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GE

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GEN

Highlights of NSPCL- DURGAPUR

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AVF/ PLF TREND SINCE INCEPTION

79

.86

61

.92

66

.12 73

.56

86

.68

79

.73

59

.35

51

.59

57

.67

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.65

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.01

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.1

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.59

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.28

64

.16

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.7

65

.15

48

.81

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.5

47

.92 5

7.1

8 64

.14

64

.96

61

.79

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.47

63

.66

64

.39 73

.02 8

5.9

33

86

.67

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.61

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2011-1

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Year

PL

F/ A

VF

AVF PLF GEN

DURGAPUR

14

.63

13

.6

13

.52

12

.34

1

12

.27

7

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.3

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.06

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FY

Auxiliary power consumption %

DURGAPUR

CW Pump efficiency improvement through polymer coating

ABSTRACT

As per EC act 2001, Power generating plant is a designated sector.

NSPCL Durgapur has 2x60 MW BTG. Our company NSPCL Durgapur is committed for

effective energy management. We are committed to save energy and reduce GHG emission.

In accordance to ENCON policy NSPCL Durgapur already has taken few initiatives to

optimize Aux power consumption.

The most important thrust area for energy conservation is efficient polymer coating on

CW/large water pump.

According to the U.S. DOE, pumps consume about 20% of all generated electricity. In a

typical surface water treatment and distribution system approx. 70-90% of energy is used for

pumping

Over an expected life span of 20 years, only 2.5 – 3% of the cost of pump operation is

related to procurement of new spares; 2 – 2.5% relates to maintenance costs rest 95% is

towards the cost of electricity to run the unit

DURGAPUR


It is well understood that roughness of the interior surface affect the flow

characteristics. A rough surface introduces micro or even macro turbulent eddies

in the boundary layer causing an increase in velocity gradient. This velocity

gradient creates resistance in passage of flow . With the application of coatings

surface roughness is reduced by many-folds, thereby allowing the flow to be

comparatively less turbulent. Due to this phenomenon overall performance i.e.

head and flow characteristics increases. For example the surface roughness of a

cast iron substrate is Ra 18.8 microns, while the surface roughness of a flu glide

coating is as low as 0.4 to 0.08 microns. Due to lower coefficient of friction

between the fluid and coating and the hydrophobic nature of the coating, the

pump consumes less power. This directly contributes to enhance the efficiency of

the Pump.

1. ROUGHNESS AMPLITTUDE &

2. HYDROPHOBIC NATURE OF POLYMER COATING

DURGAPUR


The below picture illustrates the surface roughness and flow path resistance

DURGAPUR

Effects of corrosion, Erosion-Corrosion

cavitations on the Performance of pumps

DURGAPUR

Effects of corrosion, Erosion-Corrosion

cavitations on the Performance of pumps

Value of C would depend upon the roughness only and for

any giving roughness C would be constant.

hf = (1.1758 V/CR 0.63 ) x L

The above equation is well accepted for fluid velocity

2-3 m/sec and temp within 50 deg c.

Material Hazen William Co-efficient

value

•Corroded cast Iron 60

•Corroded Steel 90

•Internally Coated steel 150

•Internally ceramic coated iron 140

DURGAPUR


Details of CW pump at NSCPL Durgapur

Sl. No Item Reference Unit UNIT # I &II

COOLING WATER PUMPS

1. Pump Type Single stage, Vertical, mixed flow: 80 D 22 -

4H4 0 / 7

2. No. Pumps Installed Nos. 5

3. Normal Operation Nos. 3

4, Location of Pumps CW Pump House

5. Total Head MWC 28.00

6. Rated Capacity M3/ /hr 6000

PUMP MOTOR

1. Motor Type SBJVe — 148 r / 03

2. Motor Rating KW 800

3. Voltage KV 6.6

4 Speed RPM 740

5 FLA A 90.4

DURGAPUR

In NSPCL Durgapur normally 3 No’s CW pump is required at

full load . CW pump contributes 14 % of station APC. Thus

CW Pump was taken for efficiency improvement.

0

5

10

15

20

25

BFP CEP FD FAN MILLING SYS ID CW CHP AND OTHRS

BREAKUP OF APC

DURGAPUR

Seal and protect new equipment exposed to erosion and corrosion

Protect pump casings, impeller blades, gate valves, water boxes and fan

blades.

Rebuild heat exchangers, tube sheets and other circulation water equipment.

Use it as a topcoat on repaired surfaces to provide an exceptionally smooth

surface.

Increase efficiency of Pumps.

Advantages of polymer coating

DURGAPUR

Dismantling of pump impeller along with bowl, suction bell and column shaft at site.

Surface preparation: Surface cleaning and drying at workshop. Also

use of Fast Cleaner 2000 Spray /Cleaner

Blend 300 to degrease the surface.

Procedures of CW Pump polymer coating

DURGAPUR

Bowl was heavily pitted.

Bowl drying and cleaning at workshop and also use of Fast Cleaner 2000 Spray /Cleaner Blend 300 to degrease the surface. Bowl cone observed heavily damaged.

DURGAPUR

All impeller pictures clearly showing severe erosion

and pitting due to corrosion

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Grit Blasting:

Blasting done as per SA 2.5 on pump bowl, bell and impeller surfaces. All surfaces made roughened ideally by

grit blasting (3-16 mesh/cm grit size).

Surface grinding:

Hand grinding with a coarse wheel or disc. This creates

increased surface area and "edges" to look into and essential for successful application

DURGAPUR

Adhesion:

Heating the repair area to 37°c - 40°c immediately before

applying brush able ceramic to dry off any moisture,

contamination or solvents and assists the ceramic system

in achieving maximum adhesion to the substrate.

Application of primer:

A suitable rust, wet, uv, high temperature, acid, alkali & oil

tolerant coating system - RL 500 PF applied on pump

bowl, bell and impeller as a primer to attain maximum adhesion.

DURGAPUR

Filling of dented surfaces : All minor dents on pump

bowl, bell and impeller repaired by applying CERAMIC

WEAR RESISTANT PUTTY

Coating and Curing : A top coat of SA 740 STANGARD -

Brush able Ceramic applied on pump bowl, bell and

impeller for protecting and repairing surfaces subject to

erosion, corrosion and wear.

Working time is 40 minutes at 21°C. After application ,

Brush able Ceramic will achieve a tack-free finish

approximately 2-3 hrs later. Functional cure is achieved in

about 24 hours at 21 Deg c. Cure may be accelerated by

using heat after the coating has been allowed to harden

under ambient conditions. Material will fully cure at 65°C in

4 hours. The maximum re-coat time between coats is 4-6

hours. Each coat should be 0.5-1.0 mm per coat. Two

coats ensure a pinhole free lining.

DURGAPUR

Dynamic balancing of impeller at work shop. Right side unbalance load is 9.66 gm and left side unbalance load is 10.22 gms against the tolerance of 27.65 gms for the both side.

Dynamic balancing of Impeller

DURGAPUR

After final coating suction bell, bowl and impeller arrived at site

DURGAPUR

CW PUMP FLOW MEASUREMENT PROCEDURES THROUGH GE PANAMETRICS PT878

Butter fly valve FLOW DIRECTION

DURGAPUR

FLOW

U/S

D/S

1. Flow measurement on single path method or Z method

2. U/S distance 4.78 m from bend 3. Spacing between sensors 389 mm

Schematic view of c.w pump along with distance measurements

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Sl

no

Description Major activity

Cw-2

Major activity

Cw-1

Major activity

Cw-5

1 OH period 21.03.2011 to 20.04.2011 01.02.2012 to 10.03.2012 03.04.2012 to 23.04.2012

2 Special job Polymer coating Polymer coating No polymer coating

3 Major OH jobs New lower and upper

shaft fitted

Two no’s new seal ring

fitted

All rubber lining bush

replaced

All ss sleeves replaced.

New lower shaft fitted

New thrust pad fitted

Two no’s new seal ring

fitted

All rubber lining bush

replaced

New top and lower shaft

fitted

New diffuser fitted

Suction bell repaired

All seal ring replaced

4 Critical

measurement

Bottom seal ring gap

maintained 0.5 mm

same same

Cw pumps OH and polymer coating in last 3 years

DURGAPUR

CW -2

BEF

COATING

AFT

COATING

Item Ref Units

Measured

Value

Measured

Value

Pump Flow

(measured) M3/Hr 6250 6860

Density Kg/M3 1000 1000

Pump Flow TPH 6250 6860

Power KW 632 619

Pump Efficiency % 68.87 77.18

SEC KWH/Ton 0.101 0.090

Performance data : CW pump-2 polymer coating

PUMP EFFICIENCY

IMPROVED BY 8 %

SEC IMPROVED BY

10 %

DURGAPUR

CW-1 BEF COATING

AFT COATING

Item Ref Units Measured Value

Measured Value

Pump Flow (measured) M3/Hr 5413 6150



Power KW 602 606


SEC KWH/Ton 0.111 0.098

PUMP EFFICIENCY

IMPROVED BY 12 %

SEC IMPROVED BY

17 %

Performance data : CW pump-1 polymer coating

DURGAPUR

CW-5 BEF OH AFT OH

Item Ref Units

Measured

Value

Measured

Value

Pump Flow

(measured) M3/Hr 5999 5868



Power KW 611.2 618


SEC

KWH/To

n 0.102 0.105

After OH of pump no 5 no

significant improvement in

efficiency was observed

Performance data : CW pump-5 without polymer coating

DURGAPUR

The above data indicating there is no major unbalance effect on pump after Polymer coating

CW Pump Before coating

PDE

H/V/A in mm/sec

After coating

PDE

H/V/A in mm/sec

CW 2 1.1/0.9/1.2 0.7/0.6/0.7

CW 1 1.2/0.9/1.0 0.7/0.8/0.5

Vibration reading of CW pumps

DURGAPUR CW pump-1&2 flow pattern since coating

As per data , post

coating Sp energy

consumption of the

both CW pump is

still lower than pre

coating value.

20.02.11 CW_1 CW_2 pre coat REMARKS

Flow - 6250

Power - 632

SEC - 0.101

20.04.11 CW_1 CW_2 post coat

Flow - 6860

Power - 619

SEC - 0.09

20.11.11 CW_1 pre coat CW_2 post coat 8 nos CT outlet v/v open

Flow 5413 6265

Power 602 598

SEC 0.111 0.095

22.05.12 CW_1 post coat CW_2 post coat

9 nos CT outlet v/v open

Flow 6150 6275

Power 606 596

SEC 0.098 0.095

04.12.12 CW_1 post coat CW_2 post coat

7 nos CT

outlet v/v open

Flow 5966 5917

Power 598 606

SEC 0.100 0.102

Post coat Avg SEC 0.099 0.095

DURGAPUR

Condenser water box DP at different combinations of CW

pump running

CW PUMP COMBINATIONS CONDENSER DP REMARKS

CW-3,4,5 0.52 COATING NOT DONE

CW -1,4,5 0.63 CW 1 COATED

CW-2,4,5 0.64 CW 2 COATED

THE ABOVE DP OBSERVED ATWHEN ALL CT FAN’S OUTLET V/V IN OPEN

CONDITION

The above data indicates clearly that condenser water

box inlet pr increased when 3 nos cw running along with

coated pump 1 0r 2.

DURGAPUR

CONDENSER DATA

CONDENSER PERFORMENCE DATA

0

20

40

60

80

100

120

140

160

Apr-1

0

Jun-

10

Aug-1

0

Oct

-10

Dec-1

0

Feb-11

Apr-1

1

Jun-

11

Aug-1

1

Oct

-11

Dec-1

1

Feb-12

Apr-1

2

Jun-

12

Aug-1

2

Oct

-12

YEAR

VA

CU

UM

U1 VAC U2 VAC CW O/L TEMP

In the FY 10-11 before Coating Condenser back pressure was very poor at

around 135 mm bar at Tcw inlet as 33 Deg Cent. Cond. outlet temp even

reached 50 deg Cent , Fourth CW pump had to be put into service to

reduce Condenser back pressure as well as outlet temp After Coating at

full load CW outlet temp is maintained maximum at 43 deg c when Tcw inlet

is 33 deg c.

DURGAPUR

Tangible gains

Cw pump-2.

Energy savings up to 12-13 :301 MWhr which is equivalent to

10.53 lacs

Pay Back period 10.63 months for continuous running.

Cw pump -1

Energy savings 345 MWhr which is equivalent to 12.21 lacs

Pay back period 6.64 months for continuous running.

Station Aux Power reduction by 0.089 %

Station Heat Rate improvement by 20 kcal/Kwhr which

contributes a significant savings of 120 lacs per annum (ie 1

kcal cost 0.07 paisa)

DURGAPUR

THANK YOU

For the attention

Monetary implications for cw pump polymer coating

C.W. -2 :

Coating cost 5.49 lacs

O/H cost 1.5 lacs

Post coating avg sec 0.095 kwhr/ton

Sec improvement = 0.101-0.095=0.006 kwhr/ton

Energy savings /day= 0.006*6000*24 kwhr

Energy savings 11-12 = 0.006*6000*24*200=0.172 mu

Energy savings 12-13 =0.006*6000*24*150=0.129 mu

Direct savings =0.172+0.129=0.301 mu *3.54=10.53 lacs( unit cost rs 3.54/-)

Payback period =7*10^5/0.006*6000*24*2.54 =10.63 months( for continuous run days)

CW-1 :

Coating cost 3.69 lacs

O/H cost 1.5 lacs

Avg sec 0.100 kwhr/ton

Sec improvement = 0.111-0.099=0.012 kwhr/ton

Energy savings /day= 0.012*6000*24 kwhr

Energy savings 12-13 = 0.012*6000*24*200=0.345 mu

Direct savings =0.345 mu *3.54=12.21 lacs( unit cost rs 3.54/-)

Payback period =8.75*10^5/0.012*6000*24*2.54 =6.64 months( for continuous run days)

APC

TOTAL SEC =0.006+0.012 KWHR/TON

ENERGY SAVINGS /DAY=(0.006+0.012)*6000*24=2.6 MWH

APC REDUCTION =0.089 %

Heat rate improvement:

Both the unit Avg vacuum reduced by 10 mm bar for each unit. This is

equivalent to 20 kcal/kwhr heat rate improvement for station.

Per day energy savings=2.88*20*10^6 kcal

Monetary savings/Annum= 2.88*20*10^6*0.07/100*300 (One kcal cost 0.07

paisa)=120 lakhs per annum.

CONCLUSION

Thermal power plants contribute 70% of India’s power generation installed capacity. It is not

possible to meet the growing demand due to long gestation period of power plant. Only solution

is to reduce auxiliary power consumption by energy conservation & energy efficiency practices.

There is tremendous scope in power sector for reducing auxiliary power consumption (APC)

Purpose of EC Act 2001 is same. In India, It is estimated that; reduction in APC by 1%,

equivalent of generation of 5000 Mu of energy per annum. Saved energy can be sold out. to

minimize the gap between supply & demand. EC act 2001 enable to do energy audit & analysis

& help us to identify number of energy conservation options. To implement EC Act-2001,

everybody made responsible for energy productivity. Hence Unlikely CW pump our management

should consider Ash water pump for coating because One P/p consumed 0.6 MU per Year.

Documents

CW Pump efficiency improvement through polymer coatingindianpowerstations.org/IPS 2013 Presentations/Day-1 at Maneksha… · 3. Normal Operation Nos. 3 4, Location of Pumps CW Pump