Cooling Tower Performance Assessment.pdf

7/27/2019 Cooling Tower Performance Assessment.pdf

1/40

CenPEEP

ProtectionProtection

ProtectionProtection

Coolin Tower

Performance Assessment

. . .

DGM (CenPEEP)


2/40

CenPEEP

Cooling Tower Thermal Performance

Im ortance of Coolin Tower Performance

Testing

Monitoring

dissipation of waste heat in power station.

More than 60 % of total heat in ut to theplant is finally dissipated as waste heat. Thewaste heat from the power plant is carried

away by circulating water and ultimately getsdissipated in cooling tower.


3/40

CenPEEP

Importance of Cooling Tower PerformanceMonitoring

The efficiency of cooling tower has direct effecton condenser vacuum and in turn, the heat rateo t e stat on.

r se n co wa er empera ure correspon sto 2.5mm vacuum loss or5 kcal/kWh in HRwhich corres onds to a rox. Rs. 68 lakhs ofloss per annum in terms of direct fuel cost for a500 MW unit.


4/40

CenPEEP

Coolin Tower Thermal PerformanceTesting

Wet Bulb Temperature (WBT) at Tower inlet

Cold Water Temperature

Hot Water Temperature

CW Flow to each Tower

Fan Motor Power


5/40

CenPEEP

Acceptable Test Conditions

CW Flow rate : 90 110% of Design

Cooling Range : 80 120% of Design

Wet-Bulb Temp : Design +/- 8.50 C

Fan Motor Power : 90 110% of Design

Average wind velocity : < 4.5 m/s


6/40

CenPEEPCooling Tower Performance

Salient Terms Used in CT Testing

pproac

at CT outlet and Inlet air Wet Bulb Temperature

Range

Difference between the Hot Water Temperature(inlet to CT) and Cold Water Temperature (outlet


7/40

CenPEEP

Coolin Tower PerformanceSalient Terms Used in CT Testing

ower apa y

tower thermal performance.

It is defined as the percentage of water thatthe tower can cool to the design cold water

temperature when the inlet wet-bulb, coolingrange, water flow rate and fan motor power are

.


8/40

CenPEEP

Coolin Tower PerformanceTower Capability

Tower Capability in Percentage = Adjusted Test Flow RatePredicted Water Flow Rate

Adjusted Test = Measured flow x { Design KW of fans}0.333

Flow Rate { Test KW of Fans }

Predicted Water Flow Rate =Calculated from Manufacturergraphs and actual test conditions

i.e. WBT, Range and Cold watertemperature.


9/40

CenPEEP

Cooling Tower Thermal Performance Testing

Tower Capability = { QT } * { CellD } * { PD }.333

* 100

pred ellT PT

Where :

QT = Measured water flow rate, t/hrQpred = Predicted water flow rate, t/hr

CellD = No. of cells for design water flow rate

CellT = No. of cells in operation during test

P = Fan motor power design, kW

PT = Fan motor power measured, kW


10/40

CenPEEP

Cooling Tower PerformancePerformance Analysis

g

CT degradation to be assessed based on

Deviation to be derived from actualtemperature and predicted cold watertemperature


11/40

CenPEEPCauses for Performance Deterioration

Fill clogging

Increase in weight of 2-3 times

Deposition in the fills comes from

the turbidity of make up water

being drawn into the cooling tower

precipitates of dissolved silica


12/40


Damage of fills.

oc ng o nozz e. Falling of nozzle.

Damage of splash bars.

Algae formation on splash bars Damaged drift eliminators

Une ual water flow in different cells.

Recirculation of vapors.

.


13/40


Hot water distribution pipe damage

and hot water channel Growth of trees/plants/bushes near cooling

tower

Overflow of cold water basin. Improper quality of water Control of COC

Rain/any other water entering in open

channel


14/40

CenPEEP

Optimizing Cooling Tower Performance

Maintaining proper L/G ratio

Visual inspection of pipes, nozzles, fills, etc., forproper water distribution.

Increasing the air flow

By increasing blade angle to obtain max allowable

By plugging all air path that do not pass through the fillzone

.

ii Sealing door openings of fan chamber.

iii Sealing the fan hub area.

v Reducing drift handled by fan


15/40

CenPEEP

Optimizing Cooling Tower Performance

Cleaning of fills with water jets

Cleaning of fills manually by removingfrom tower

Cleaning of cold water basin during

Regular cleaning/checking of nozzles.

u u r zto maintain required FRC


16/40

CenPEEP


17/40

CenPEEP

Coolin Tower Thermal Per ormance TestinLocation Of Inlet Wet Bulb Temperature for Station with Counter Flow Tower

L L

L < 2 Meters X Measurement Station.


18/40

CenPEEP

Coolin Tower Thermal Per ormance TestinLocation Of Inlet Wet Bulb Temperature for Station with Cross Flow Tower

LL

L < 2 Meters, X Measurement Station.


19/40

CenPEEPCooling Tower Thermal Performance Testing

Wet Bul Temp. measurement setup


20/40

CenPEEP

Grid setu or Cold Water Tem . measurement



21/40

CenPEEP


Grid setup for Cold Water Temp. measurement of single cell


22/40

CenPEEP


Grid setup for Cold Water Temp. measurement of single cell


23/40

CenPEEPGrid Measurement for Cold Water Temperature for one Cell

Grid of 48 probes


24/40

CenPEEPCT Performance Test

Design Cell -14 Cell - 11 Total Tower

. . .

HWT 44 40.51 41.13 41.1

. . . .

CW Flow 2222/40000 2520 2515 44188

Fan Power 47.81 45.65 43.84 44.17verage

Range 12 9.18 9.29 9.50

Approach 4.3 6.81 7.42 7.0

Effectiveness(Actual)

73.62 57.4 55.59 57.58

Effectiveness 63.22 64.4 64.32

(EXP)

Capability 100 87.13 80.04 85.07


25/40


90% Flow; Cold Water vs. Wet Bulb

37.0

32.033.034.035.0

36.0

WATE

R

ATUR

E

27.028.029.030.031.0

COLD

T

EMPE

23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0

Wet Bulb (C)

C-8.8C B-11.0C A- 13.25C


26/40



37.0

33.0

34.035.0

.

ATER

ATUR

E

29.0

30.0

31.0

.

COLD

T

EMPE

.

23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0

Wet Bulb (C)

C-8.8C B-11.0C A- 13.25C


27/40


110 % Flow; Cold Water vs. Wet Bulb

37.0

33.034.035.0

36.0

WATE

R

ATUR

E

29.0

30.031.0

.

COLD

T

EMPE

.

23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0

Wet Bulb (C)

C-8.8C B-11.0C A- 13.25C


28/40



C

31.032.033.034.035.036.0

.

DWATE

RATU

R

27.028.029.0

.

23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0

COL

TEMP

Wet Bulb (C)

C-8.8C B-11.0C A- 13.25C

Test WBT 25.7 C


29/40


Cold Water vs. Cooling Range

)

30.2

30.4

30.6

.

WATE

R

TURE

(C

29.4

29.6

29.8

30.0

COLD

TE

MPER

8.0 9.0 10.0 11.0 12.0 13.0 14.0

COOLING RANGE (C)

90% Flow


30/40


Cold Water vs. Cooling Range

32.0RE

31.0

31.5

EMPERAT

)

29.5

30.0

.

W

ATER

(

29.0

8.0 9.0 10.0 11.0 12.0 13.0 14.0

COOLING RANGE C

COL

90% Flow 100% Flow 110% Flow Test Range

Test Cooling Range 10.1 C


31/40


Cold Water vs. Predicted Flow

30.4

30.6

.

TER

URE(C)

30.0

30.2

COLDW

M

PERAT

29.6

.

80 85 90 95 100 105 110 115

T

Predicted Flow (%)

Test Cold Water Temp 35.9 C

C


32/40


Cold Water vs. Predicted Flow

37.0E

33.0

35.0

PERA

TU

29.0

31.0

A

TERTE

(C)

25.0

27.0

25,000 35,000 45,000 55,000 65,000 75,000 85,000

COLD

Predicted Flow (t/hr)

Test Cold Water Temp 35.9 C

Predicted Flow 77,000 t/hr, Actual Flow - 30,977 t/hr

C PEEP


33/40

CenPEEPDEPOSITS IN FILL

C PEEP


34/40

CenPEEPALGAE FORMATION

C PEEP


35/40

CenPEEPONLINE FILL CLEANING RIHAND

CenPEEP


36/40

CenPEEPAIR PASSAGE THROUGH SHAFT OPENING

CenPEEP


37/40

CenPEEP

OPENING

CenPEEP


38/40

CenPEEPSEALING FAN HUB AREA

CenPEEP


39/40

CenPEEPSEALING FAN HUB AREA

CenPEEPR i W t E t i C ld W t B i


40/40

CenPEEPRain Water Entering Cold Water Basin

Documents

Cooling Tower Performance Assessment.pdf