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POWER PLANT POWER PLANT FAMILIARIZATION FAMILIARIZATION

CHEMISTRYCHEMISTRYSANDIPT VARSHNEY Sr.MANAGER (CHEM.)

WHY SCARCE RESOURCE IN PLENTY

OF THE TOTAL WATER IN HYDROLOGICAL CYCLE ABOUT 97% IS OCEANIC(BRACKISH)

REMAINING 3%=100 UNITS IS FRESH WATER IN ALL FORMS.

OF THESE 75 UNITS IS LOCKED IN ICE CAPS AND GLACIERS.

14 UNITS IS GROUND WATER BELOW750MTS.

11* UNIT IS GROUND WATER ABOVE 750 MTS

HOW SCARCE IS WATER(*) INCLUDES:-

0.035 UNITS ATMOSPHERIC WATER

0.03 UNITS RIVER WATER

0.06 UNITS SOIL MOISTURE

0.3 UNITS IN LAKES.

NEED TO CONSERVE WATER

THOUGH AVAILABLE IN PLENTY USABLE WATER IS SCARCE

WATER REQUIREMENTS IN POWER PLANTS

CONDENSOR COOLING

AUXILLARY COOLING

FIRE FIGHTING

WATER TREATMENT PLANTCLARIFIED WATERDRINKING WATERDM WATER FOR STEAM GENERATION

SOURCES OF WATER

• SEA WATER• RIVERS• LAKES• CANALS• BORE WELLS• RECYCLED WASTEWATER

TYPES OF IMPURITIES IN RAW WATER

• SUSPENDED IMPURITIES

• DISSOLVED IMPURITIES

• BIOLOGICAL MATTER

• POLLUTANTS (INDUSTRIAL & DOMESTIC)

PTPlant

D M P lant

W TP

S W AS

C W Trea tm entS ys tem

M ain P lant

A m bient A irQ u a lity

M on ito ring

S tack E m iss io ns

E ffluen t T rea tm ent

E n viron m ent m o niter ing

N aph tha& N atu ra l G as

A n a lys is

H yd ro lic & lu beO il A n a lys is

F u e l & O il

Chem istry Section

TREATMENT PROCESS

Pre-treatments of the plant water include:-

• Clarification• Disinfection by chlorine• Removal of organic matter• Filtration• Chemical treatments

PR E T R E AT M E N T PL AN T D E M I N E R AL I Z AT I O N PL AN T

W AT E R T R E AT M E N T PL AN T

WATER TREATMENTS

PRETREATMENT DEMINERALISATION COOLING WATER

TREATMENT STEAM WATER CYCLE

TREATMENT

Salient Features of ANTA

• Units Installed :3 GTs, 3 WHRBs, 1 STG• Capacity

– Gas Turbines :- 3 x 88.71 MW– Steam Turbine :- 1 x153.2 MW

• Source of water :- RMC of Kota barrage on Chambal

River.• CW system Flow :- Approx. 30660 M3/ Hr.

Raw water Characteristic

• pH :- 8.2• TDS:- 170 ppm

• Total Hardness:- 85 ppm as CaCO3

• Ca. Hardness:- 64 ppm as CaCO3

• Magnesium :- 21 ppm as CaCO3

• Alkalinity:- 101 ppm as CaCO3

• Chlorides:- 28 ppm • Organics:- 1.5 to 2.5

 

 Storage Tank

Pressure Filter

Raw Water fromReservoir

Chlorine Lime Alum Clarifier

 

 

 

PROCESS FLOW SHEET OF PRETREATMENT PLANT

To DMplant

Raw

Water

Process flow sheet

PressureFilter

ACF Cation

D / G

WBASBA

MixedBed

Clarifier

DM waterStorage

Tank

D M PLANT

DEMINERALISATION PROCESS

FromACF

Cation MixedBed

Regeneration with caustic

Regenera-tion with HCl

WBA

Analysis

SBA

Analysis

Is quality ok

Analysis Analysis

Regeneration with HCl, NaOH

Is quality ok

Is Quality ok

D/G

DMW storage tank

Is Quality ok

STEAM WATER CYCLE TREATMENT

• LP DOSING (AMMONIA+HYDRAZINE)

• HP DOSING (TSP+ CAUSTIC)

CW pump House

Reservoir Reservoir

Outlet Channel

condenser

Inlet Gate

Outlet Gate

Right Main Canal

InletChannel

CW SYSTEM

WTP

Raw/CW waterP/H

Drinking water

CW make up line

Raw water line

Cooling Towers

SCALING PROBLEM• Steam turbine operation started in August

1990.• 1st Scaling Problem : July 1991, after just

2 – 3 months of closed cycle operations• 1st Chemical cleaning : February . 1992• 2nd Scaling Problem : September 1993

within 2 months of closed cycle operation.• 2nd Chemical cleaning : October 1993

Scales Properties• Thickness : 0.3 to 0.5 mm • Major Constituents :

– Carbonates of Calcium – 42 %– Carbonates of Magnesium – 6%– Quantity of scales removed – 5 to 7 MT

• Chemical cleaning done using inhibited Sulphamic acid.

CW Treatment • In house effort in association with

NTPC R&D.• Started in1994• Chemical Dozed

– pH : 6.8 to7.8– Liquid Chlorine: 0.5 ppm (free chlorine– Zinc Sulphate : 3 to 5 ppm– Sulphuric Acid : to maintain pH– Polyphosphate : 15 to 20 ppm

Parameters maintained

S.No. PARAMETER UNIT REQUIRED RANGE

AVERAGE VALUE

1. pH - 6.5 – 7.5 7.1 ± 0.4

2. Sp. Conductivity us/cm - 800 – 1100

3. Total Hardness mg/l 300 – 500 450 -- 500

4. Chlorides as cl mg/l 150 – 250 100 – 125

5. Silica as Sio2 mg/l 75 18 – 25

6. Inorganic Phosphate mg/l 15 – 20 10 – 15, <5.00**

7. Zinc as Zn Mg/ l 3 – 5 3, < 1.0*

8. COC -- 3 – 5 4.0

**From year 2000 onwards Phosphate &Zinc values restricted to 5 mg/ l and 1mg/ l respectively due pollution norms.

Condenser Performance before and after chemical cleaning

 

S.No.

PARAMETER

UNIT DESIGN VALUE DATA

PG TEST DATA

AUG.91 (Before descalin

g)

OCT.92(Before descalin

g)

Dec.93 (After

chemical cleaning)

March 04,

1.   

CW Inlet C 32.0 32.8 33.0 27.5 23.3 27.9

2.   

CW Outlet

C 41.8 43.3 45.0 38.1 33.0 36.9

3.   

Δ Temp. C 9.8 10.5 12.0 10.6 9.7 9.0

4.   

TTD C 3.8 3.6 15.69 12.7 3.7 3.5

5.   

Vacuum Bar

(Abs)

0.102 0.106 0.204 0.155 0.078 0.08

Benefits of the Treatment

• No scaling problem observed in last TEN years.

• No condenser tube leakages occurred in last TEN years.

• Conservation of water by maintaining COC of 5.0.

• Optimum capacity generation by steam turbine, due to improved vacuum.

• Treatment has enabled in indirect saving of Rs 204 lacs/year.

Expected Reduction of Effluents & makeup water for a 1200 MW

station

Make-up Consumptive EffluentsScheme water water water

(cum/Hr) (cum/Hr) (cum/Hr)Conventional scheme 9925 4030 5895

Improved Scheme 6075 4030 2045

Zero Discharge Scheme 4031 4030 practically

zero

WATER REQUIREMENT AT DIFFERENT COC(ANTA)

COC EVAPORATION LOSS

M3/HR

DRIFT LOSS

M3/HR

BLOW DOWN REQD M3/HR

TOTAL MAKE UP

REQD M3/HR

2 600 100 700 1400

3 600 100 350 1050

4 600 100 233 933

5 600 100 165 865

6 600 100 140 840

WATER MANAGEMENT IN ANTA GAS POWER PROJECT

WATER UTILISATION PATTERN

AREA APP. CONSUMP. PER MONTH

PURPOSE

INDUSTRIAL COOLING

WATER450000 M3

Main condenser cooling water & air conditioning system, boiler feed water

DOMESTIC PURPOSE 32000 M3

Potable water to main plant & residential colony

PROCESS CONTROL 7000 M3

PT & DM Plant effluent treatment

Water Effluents Discharges from Anta

• Plant Effluents: 4000 to 5000 M3/ month.• C W Blow down : 45,000 to 50,000M3/

month.• Boiler Blow down:1300 to 1500 M3/ month.• Domestic Sewerage Water : 10,000 - 12,000

M3/ month.• Total Discharges during a month : 62,000 to

70,000M3/ month.

FUEL & OIL

• Analyse Natural Gas For Its Calorific Value On Weekly Basis

• Checking Naphtha Parameters On Requirement

• Analysis Of Lube Oils and Hydraulic oils On Regular Basis to study The Condition Of Oil .

ENVIRONMENT

• Stack Monitoringo Sox & Nox Monitoring

• Ambient Air Quality Monitoringo SPM & RSPM, Sox & Nox Monitoring

Three Locations Inside & 24 Locations Outside The Plant Premises Up to a Distance of 5 Kms.

• Effluent Quality As Per Environmental Normso Main Plant & Sewage Treatment Plant

Effluent Quality Monitoring

(i)PROCESS WATER

StageCapacity

MW

Water Consumption

For Boiler make up

Other ProcessLosses

Total Consumption

in M3

AverageConsumptio

nPer Day

One 419.33 33928 M3 55065 M3 88993 M3 243.8 M3

Water Consumption per unit generation : 1.5 -1.8 Litres/ Kwh

(i)COOLING WATER

StageCapacity

MW

Once through cooling Closed cycle coolingAC & other

coolingHoursWater

consumptionHours

Water consumption

One 419.33 1483 31826070 M3 6210 3740400 M3 25400 M3

Av. Consumption per Day in M3 515054.3 14400.0 69.6

(i)DOMESTIC WATERWater Consumption in 2009- 10, M3

Average ConsumptionIn M3 /Day

336000.0 920.5

RAW MATERIAL CONSUMPTION:

S.NoName of Raw

Material /QuantityName of Product /

Quantity

Consumption of Raw Material Per unit output

During2008-09

During2009 - 10

1Natural Gas/

525482698.0 SMCElectricity /

2898.631 MU0.2265

Smc/Kwh0.2201

Smc/Kwh

2Naphtha /

62897.00 KLElectricity / 103.142 MU

0.2591Litres./Kwh

0.2541Litres./Kwh

3 DM Water / Electricity0.0128

Litres/ Kwh*0.0104

Litres/ Kwh*

4Hydrochloric Acid

(30%)Electricity

0.0090 Gms/Kwh

0.011 Gms/Kwh

5 Caustic Soda Electricity0.0015

Gms/Kwh0.0016

Gms/Kwh

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