BoP - Water Treatment and Corrosion Issues & Remedies Ashwini Sinha.pdf · A Maharatna Company...

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BoP - Water Treatment and Corrosion Issues & Remedies

Ashwini K Sinha

AGM (NETRA)[email protected], [email protected]

23rd May 2012

NTPC Energy Technology Research AllianceDeveloping Economic and Green Energy Technologies

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1.0 Introduction Water Availability & Utilization Power Scenario with possible Water Foot Prints

2.0 Issues Related to BOP Summary of issues in BoP Schematics of Power Plant & Water Treatment Technologies Cost of Corrosion in Power Plants Quantity of Water required for different applications Quality of Water Required Commercial

3.0 Issues related to: Efficiency, Availability & Performance Reliability of Structures & Pipelines Optimizing COC & Recycling R&D and New Technologies

4.0 Role of Service Providers

Presentation Outline

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The UN estimates that by 2050, half the World’s population will live in nationsthat are short of Water. Water is needed throughout the energy sector at eachstep-energy for extraction & production, refining & processing, transportation &storage and electric power generation it self. It is estimated that waterconsumption to generate electricity will more than double over the next 40 Years

Water footprint of an individual - sum of his or her direct and indirect freshwateruse. The direct water use is the water used at home, while the indirect wateruse relates to the total volume of freshwater that is used to produce the goodsand services consumed.

Water Foot Prints

S.No. Country/Type Water Foot Print m3/yr1 Average Global 13852 USA 28423 China 10714 India 10895 Daily vegetarian diet 1500 lit6 Daily Non-Vegetarian diet 3400 lit

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NETRAWater Foot Prints

Research by the Cranfield University calculated the amount of water required to produce various common foods in the United Kingdom:

S.No Product Amount of Water Litres

1 1 cup of tea 32.42 1 imperial pint of beer 1603 1 glass of wine 1204 1 glass of milk 2005 1 kilogram (2.2 lb) of beef 15,0006 1 kilogram (2.2 lb) of poultry 6,0007 250 grams (8.8 oz) packet of M &Ms 11538 575 grams (20.3 oz) jar

of Dolmio pasta sauce 202

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1.0 IntroductionWater Availability & Utilization Power Scenario with possible Water Foot Prints





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NETRAWater Availability & Utilization

Water withdrawal Water Consumption

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In India, the total utilizable water resource is assessed as 1123 BCM.

The per capita availability of water at national level has been reduced fromabout 5177 cubic meters in 1951 to the estimated level of 1,820 cubicmeters in 2001 with variation in water availability in different river basins.Given the projected increase in population by the year 2025, the per capitaavailability is likely to drop to below 1,000 cubic metres, which could belabeled as a situation of water scarcity

Water Demand (in BCM) for various Sectors

Water Availability & Utilization

Sector Standing Committee of MoWR NCIWRDYear 2010 2025 2050 2010 2025 2050

Irrigation 688 910 1072 557 611 807

Drinking 56 73 102 43 62 111

Industry 12 23 63 37 67 81

Energy 5 15 130 19 33 70

Others 52 72 80 54 70 111

Total 813 1093 1447 710 843 1180

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NETRAPower Scenario of India

Consumptive Water foot print: Thermal – 394804 – 723817 M3/hr @ 3 – 5.5 m3/MWh

Installed Capacity of India as on 31.03.2012 (Source CEA)

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1010

Note: Capacity includes capacity under construction; Map not to scale

Geographical spread of generating facilities

RIHAND(3,000 MW)RIHAND(3,000 MW)SINGRAULI

(2,000 MW)SINGRAULI(2,000 MW)

FARIDABAD(430 MW)FARIDABAD(430 MW)

DADRI(817 MW)DADRI(817 MW)

NCTPP(1,820 MW)NCTPP(2,310 MW)

ANTA(413 MW)ANTA(413 MW)

AURAIYA(652 MW)AURAIYA(652 MW)

UNCHAHAR(1,050 MW)UNCHAHAR(1,050 MW)

TANDA(440 MW)TANDA(440 MW)

KAHALGAON(2,340 MW)KAHALGAON(2,340 MW)

FARAKKA(2,100 MW)FARAKKA(2,100 MW)

KORBA(2,600 MW)KORBA(2,600 MW)

VINDHYACHAL(4,260 MW)VINDHYACHAL(4,260 MW)GANDHAR

(648 MW)GANDHAR(648 MW)

KAWAS(645 MW)KAWAS(645 MW) TALCHER KANIHA

(3,000 MW)TALCHER KANIHA(3,000 MW)

RAMAGUNDAM(2,600 MW)RAMAGUNDAM(2,600 MW) SIMHADRI

(2,000 MW)SIMHADRI(2,000 MW)

KAYAMKULAM(350 MW)KAYAMKULAM(350 MW)

TALCHER Thermal(460 MW)TALCHER Thermal(460 MW)

KOLDAM(800 MW)KOLDAM(800 MW)

TAPOVAN VISHNUGAD(520 MW)TAPOVAN VISHNUGAD

(520 MW)

LOHARINAG PALA(600 MW)LOHARINAG PALA

(600 MW)

SIPAT2,980 MWSIPAT2,980 MW

BARH3,300 MWBARH3,300 MW

BTPS(705 MW)BTPS(705 MW)

BONGAIGAON(750 MW)BONGAIGAON(750 MW)

VALLUR(1,500 MW)VALLUR(1,500 MW)

MAUDA(1,000 MW)MAUDA(1,000 MW)

RGPPL(1480 MW)RGPPL(1480 MW)

IGSTPP(1,500 MW)IGSTPP(1,500 MW)

DURGAPUR(120 MW)DURGAPUR(120 MW)

BHILAI574 MWBHILAI574 MW

ROURKELA(120 MW)ROURKELA(120 MW)

NABINAGAR(1,000 MW)NABINAGAR(1,000 MW)

GAS POWER STATIONS

COAL POWER STATIONONGOING HYDRO POWER PROJECTS

ONGOING THERMAL PROJECTS

NTPC Pan India Presence

JVs, 4364

Northern, 5490

NCR, 4837Western,

9973

Southern, 4950

Eastern, 7900

No. of plants

Capacity MW

NTPC OwnedCoal 16 29195Gas/Liquid fuel 7 3955Sub-Total 23 33150Owned by JVsCoal & Gas 7 4364Total 30 37514

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1111

By 2032, NTPC targets a capacity of 128 GW with 28% capacity from non-fossil sources

Coal Gas Nuclear Hydro Renewables

2032~128 GW

2017~75 GW

2010~32GW

Consumptive Water footprint (Coal)2010 – 77760 m3/hr (25920 MW), 2017 – 168750 m3/hr (56250 MW), 2032 – 215040 m3/hr (71680)

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Quantity of water required & achieving required application

Effects of Quality of water on the performance of different systems

Reliability of various systems such as CHP, AHP, DM Plants, Cooling Towers, Pipelines, RCC Structures, Firefighting systems, etc

Optimizing of COC & Water Recycling

R&D & New Technologies for water required

Corrosion Protection and improving the performance of Structures, Pipelines – Anticorrosive Coatings, Cathodic Protection, Water Treatment or Combination

Cleaning of Reservoirs

Control of Organic impurities

Use of Municipal Treated Sewage Water as a make up water

Recycling of Waters & waste Waters – Technologies required

Summary of Issues of BoP

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NETRATypical Thermal Power Plant

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Key to Typical diagram of a coal-fired thermal power station

1. Cooling Tower 2. Cooling Water Pump 3. Transmission Line (3 Phase)

4. Step-up Transformer (3 Phase) 5. Electrical Generator (3 Phase)

6. Low pressure Steam Turbine 7. Condensate Pump 8. Surface Condenser

9. Intermediate pressure Steam Turbine 10. Steam Control Valve

11. High pressure Steam Turbine 12. Deaerator 13. Feed Water Heater

14. Coal Conveyer 15. Coal hopper 16. Coal Pulverizer

17. Boiler Steam Drum 18. Bottom Ash 19. Superheater

20. Forced draught (draft) fan 21. Reheater 22. Combustion air intake

23. Economizer 24. Air Preheater 25. Electrostatic Precipator

26. Induced draught (draft) fan hopper 27. Flue Gas Stack

Typical Thermal Power Plant

NETRAA Maharatna Company

1717

Typical Thermal Power Plant

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NETRATypical Scheme for Water Usage

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NETRATypical Scheme for Clarification

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NETRATypical Scheme for Demineralization

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NETRATypical Scheme for CPU

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NETRATypical Scheme for Two Stage RO

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NETRATypical Scheme for RO Treatment

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NETRATypical Scheme for RO and Mixed bed

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NETRATypical Steam Water Cycle

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2727

COST OF CORROSION

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2828

COST OF CORROSION

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NETRACosts of Corrosion ProblemsAffecting Fossil Steam Plants

Corrosion Problem O&M Non- Fuel Related

Corrosion CostUS $

Depreciation Corrosion Cost

US $

Total Corrosion CostUS $

All Corrosion Problems in Fossil Steam Plants

3,43,50,00,000 1,14,20,00,000 4,57,70,00,000

Waterside/Steam side Corrosion of Boiler Tubes

91,60,00,000 22,84,00,000 1,14,44,00,000

Turbine CF & SCC 45,80,00,000 14,27,50,000 60,07,50,000

Oxide Particle erosion of Turbines

27,48,00,000 8,56,50,000 36,04,50,000

Heat Exchanger Corrosion 27,48,00,000 8,56,50,000 36,04,50,000

Fireside Corrosion of Water wall tubes

18,32,00,000 14,27,50,000 32,59,50,000

Generator clip to strand Corro 18,32,00,000 2,85,50,000 21,17,50,000

Copper deposition in turbines 9,16,00,000 5,71,00,000 14,87,00,000

Fireside Corrosion of SH & RH tubes

9,16,00,000 5,71,00,000 14,87,00,000

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NETRACosts of Corrosion ProblemsAffecting Fossil Steam Plants

Corrosion Problem O&M Non- Fuel Related Corrosion

Cost US $

Depreciation Corrosion Cost

US $

Total Corrosion CostUS $

Corrosion of FGD system 4,58,00,000 8,56,50,000 13,14,50,000Liquid Slag Corrosion of Cyclone Boilers

9,16,00,000 2,85,50,000 12,01,50,000

Backend dew point corrosion 9,16,00,000 2,85,50,000 12,01,50,000

Generator Cooling water clogging & plugging

9,16,00,000 2,85,50,000 12,01,50,000

FAC of steam plant piping 9,16,00,000 2,85,50,000 12,01,50,000

Corrosion of service water, circulating water and other water systems

9,16,00,000 2,85,50,000 12,01,50,000

All other (Corrosion of structures, ash handling equipment, CHP, oil pipes & tanks, electrical equipment,

45,80,00,000 8,56,50,000 54,36,50,000

Total 3,43,50,00,000 1,14,20,00,000 4,57,70,00,000

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NETRAWater Requirements for Power Generation

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NETRAWater Losses from Power Generation

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NETRAProcess Flow Schematic for Wet Recirculating Cooling Water System

1 GPM = 0.2271 M3/hour

34

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NETRAWater Requirements

Water Requirements for a 500 MW Unit (Ref. Flow schematic)

S.No. Description

Flow rate

GPM M3/Hr

1 Boiler Feedwater 7645 1736.18

2 Circulating Water 187600 42603.96

3 Evaporation & Drift 6415 1456.847

4 Make up 9537 2165.853

5 Blowdown water 3161 717.8631

35

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NETRAWater Requirements for Thermal Power Plants

Water requirement for different type of Power Plants

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NETRATypical Water Requirements of TPS

Water Requirement & Consumption in a Coal fired Power Plant

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NETRATypical Water Requirements at Power Plant

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S.No Description 1 X 500 MWM3/hr

2 X 660 MWM3/hr

1 Evaporation & Drift from CT 1160 2555

2 HVAC System Losses 50 100

3 Potable Water System 70 100

4 Evaporation losses in Ash Dyke 200 570

5 Losses in Cycle make up 42 80

6 Losses in Service Water System 350 300

7 Evaporation Losses in Reservoir - 100

8 Total Consumptive Water 1872 3805

9 Water for Ash Handling 1410 1650

10 Water recovered in AWRS 1230 1190

11 Additional Make up 180 460

12 Total Water Drawl 33 Cusec(Max)

38 Cusec (Normal)50 Cusec (Max)

Water Optimization in New Plants

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NETRASOURCES OF WATER FOR INDUSTRIAL APPLICATIONS

• RIVER

• SEA

• PONDS

• LAKES

• IRRIGATION CANALS

• BOREWELLS

• RECYCLED WATER

• RESORVOIRS

• RECYCLED EFFLUENTS

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NETRACHARACTERISTICS OF WATER & SOURCES OF IMPURITIES

IMPURITIES IN WATER:

• BACTERIA & VIRUSES

• MICRO – ORGANISMS

• TURBIDITY

• COLOUR

• MINERALIZATION

• METALLIC

• DISSOLVED GASES

• AMMONIA

• ORGANIC MATTER

• POLLUTANTS

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NETRAAPPLICATIONS OF WATER INPOWER PLANTS (THERMAL)

• COOLING OF CONDENSATE

• AUXILIARY COOLING

• BOILER WATER

• ASH HANDLING WATER

• COAL DUST SUPPRESSION WATER

• WASHING

• DRINKING

• SANITATION

• FIRE WATER

• SERVICE WATER

• HVAC SYSTEM

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Typical Deionized water requirements

DM Water Quality requirements

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NETRASummary of Primary and Secondary Targets for Drum-type Boilers under Steady State Operation (expressed as ug/kg unless otherwise stated)

Boiler Class

Parameter 60 Bar –Gas Fired

100 Bar –Coal Fired



Feed-water

Conductivity(u/S/cm at 25°C)

<-local decision to achieve primary target in boiler water->

Sodium (Na) <-local decision to achieve primary target in boiler water->

Sulphate (SO4) <-local decision to achieve primary target in boiler water->

Dissolved Oxygen-In condensate

<50 <50 <50 <50

Dissolved Oxygen-In Feed

<7 <7 <5 <5

Oil <200 <200 <200 <200

TOC

Hydrazine (N2H4) <— 2 x Dissolved Oxygen concentration —>

4545

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Ammonia (NH3) <— < 500 when copper alloys present —>< 1000 when copper alloy absenti.e. when SS or Titanium are present

pH (at 25oC) <— 8.8 - 9.2 (or 8.8 - 9.4 when copper —>alloys absent)

Total Metals <20 <20 <20 <20Spray Water Sodium (Na)

10

(without RH)

10(without RH)

5(without RH)

5(without RH)

4646

Summary of Primary and Secondary Targets for Drum-type Boilers under Steady State Operation (expressed as ug/kg unless otherwise stated)

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Boiler-water

1. Non-volatile Phosphate Treatment

Chloride (NaCl) as Chloride

< 3000 < 2000 < 1000 < 500

Silica (SiO2)(at pH - 9)

< 5000 < 1500 < 300 < 200

Sulphate (SO4) <-local decision to achieve primary target in boiler water->

Disodium/ TrisodiumPhosphate

2000To

6000

2000To

4000

1000To

2000

1000To

2000

All Volatile Akali Treatment

Chloride (NaCl) as Chloride

NA < 120 < 120 NA

Silica (SiO2)(at pH - 9)

< 350 <250 < 150 < 100

Sulphate (SO4) NA LD LD NA

4747


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Saturated Steam

Silica (Sio2) <20 <20 <20 <20<10 (depending upon

design) with RH

Sodium (Na) < 20 < 10 < 6 < 5< 3 (On AVT

4848


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NETRAEPRI Guidelines for Cooling Waters

Water Quality EPRIGuidelines

RemarksParameter

Units

Ca Mg/lCaCO3

900(max)

Ca X SO4 (Mg/l)2 500000MAlkalinity

Mg/lCaCO3

30 – 50220 - 250

Without ScaleInhibitorWith ScaleInhibitor

Mg XSiO2

Mg/lCaCO3 XMg/lSiO2

35000

SO4 Mg/lSiO2 Mg/l 150PO4 Mg/l

Fe (Total) Mg/l < 0.5

Mn Mg/l < 0.5

Cu Mg/l < 0.1

Al Mg/l < 1

S Mg/l 5

NH3 Mg/l < 2 For copper basedalloys present in thesystem

pH 6.0 – 7.27.8 – 8.4

Without ScaleInhibitorWith Scale Inhibitor(Higher operating pHis possible with newalkaline treatments)

TDS Mg/l 70000

TSS Mg/l < 100< 300

For Film type FillSplash type Fill

BOD Mg/l

COD Mg/l

LSI < 0

RSI > 6

PSI > 6

Desirable: BOD < 5 ppm, Turbidity < 2 NTU, Sulphide < 0.1 ppm (for Cu based systems), Chloride < 200 ppm for SS 304 (upto 500 ppm short duration & < 500 ppm for SS 316 (3000 ppm short duration)

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NETRACommercial Aspects of Water Use

S.No State Water Charges

Cess Remarks

1 Kerala Re 1/m3

2 Delhi Rs. 1.5 Lac per Cusec

3 Andhra Pradesh Rs.7.98/m3

4 Uttar Pradesh Rs. 1.16/m3

5 Gujarat Rs. 13.31/m3

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NETRACommercial Aspects of Water Use

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NETRACost of Chemicals used in CW Treatment

S.No. Chemical Rate Rs.(Per Kg/L)

Annual Cost of Chemical per 1000 m3/hr make up (Rs.)1 ppm 2 ppm 3 ppm 4 ppm 5 ppm

1 HEDP 50% 50 438000 876000 1314000 1752000 21900002 PBTC 50 % 180 1576800 3153600 4730400 6307200 78840003 Polyacrylate 100 876000 1752000 2628000 3504000 43800004 Polymaleic 150 1314000 2628000 3942000 5256000 65700005 Zinc sulphate 25 219000 438000 657000 876000 10950006 BTA 450 3942000 7884000 11826000 15768000 197100007 HEDP 60 % 60 525600 1051200 1576800 2102400 26280008 ATMP 50 438000 876000 1314000 1752000 21900009 Carboxylate/

Sulphonate150 1314000 2628000 3942000 5256000 6570000

10 Carboxylate/Sulphonate/nonionic

200 1752000 3504000 5256000 7008000 8760000

11 Si & Mg inhibitor

400 3504000 7008000 10512000 14016000 17520000

12 SHMP 35 306600 613200 919800 1226400 153300013 Molybdate 250 2190000 4380000 6570000 8760000 1095000014 silicate 180 1576800 3153600 4730400 6307200 7884000

1 ppm = 1 Kg

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NETRAWater Treatment Concerns

Particle EntrapmentGrowth Sites

Corrosion

Deposition Biofouling

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Table 1 Thermal conductivity comparison of deposit-forming compounds

and bio-film

Substance Thermal Conductivity(W m-1K-1)

CaCO3 2.6

CaSO4 2.3

Ca3 (PO4)2 2.6

Fe2 O3 2.9

Analcite 1.3

Bio-film 0.6

Optimizing COC

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Table 2 - Effect of CaCO3 scale (of varying thickness) on overall heat transfer coefficient

Scale Thickness, Inches

Overall heat transfer coefficient, BTU per sq ft per deg F

Percent loss in BTU per sq ft per deg F

0.000 92.77 00.012 73.68 20.580.024 61012 34.120.036 52.20 43.730.048 45.60 55.850.060 40.46 56.39

0.0625 (1/16 in.) 39.52 57.40

Optimizing COC

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Table 3 - Effect of CaSO4 scale (of varying thickness) on overall heat transfer coefficient

Overall heat transfer scale thickness, inches

Coefficient, BTU per sq ft per deg F

Percent loss in BTU per sq ft per deg F

0.000 92.77 00.012 63.10 31.980.024 47.81 48.460.036 38.49 58.510.048 32.20 62.000.060 27.69 70.00

0.0625 (1/16 in.) 26.89 71.00

Optimizing COC

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Relative increase in power for condenser and chiller units calculated according to fouling factors

Fouling Factor Condenser Factor Chiller Factor

0.0005 1.00 1.00

0.001 1.05 1.04

0.002 1.14 1.09

0.003 1.22 1.17

0.004 1.30 1.24

Optimizing COC

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0.01 ata increase in Condenser Back-pressure= 10 Kcal/KWH increase in Heat Rate of TurbineLoss due to variation in Condenser Back-pressure

Rating Annual Loss Life Time LossRs. Lacs (Aprox.) Rs. Lacs

210 MW 30.25 756.25500 MW 71.05 1776.25

Optimizing COC

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NETRAEffects of Corrosion, Erosion-Corrosion, Cavitations on the Performance of Pumps

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

• Unlike motors, the efficiency of pumps is highly influenced by the system they are supplying

• In a typical surface water treatment and distribution system approx. 70-90% of energies used are for pumping

• Over an expected life span of 20 years, only 2.5 – 3% of the cost of pump operation related to the purchase of the equipment. Further 2 – 2.5% relates to maintenance costs. 95% is towards the cost of electricity to run the unit

•In any pumping system, over the years, the hydraulic passages of casings & impeller vane shape gets damaged due to wear, tear & corrosion, also the clearance in wear rings increases substantially. All these damages lead to head and flow losses & ultimately deteriorate hydraulic performance. Due to this deterioration of performance the power consumption increases putting pressure on energy demand due to inefficient operation of pump.

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NETRAEffects of Corrosion, Erosion-Corrosion, Cavitations on the Performance of Pumps

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The power required for flow of water through pipelines is as follows:To overcome physical level difference from start of pipeline, which is at low level to end of pipeline which is at higher level. The power required is constant as the static head is constant.

To overcome the frictional resistance to the flow of water. This is known as frictional head loss.

There are two types of friction losses:

Major Friction Loss – This is the friction of inside surface of pipeline to the flow of water. For large diameter and long lines this loss consumes large power and therefore energy.

Minor Friction Losses – Minor friction losses are:Contraction lossEnlargement lossGate valve, check valve lossBend loss

Effects of Corrosion, Erosion-Corrosion, Cavitations on the Performance of Pumps

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Friction Head Loss:

Inside surface of pipelines in contact with water exerts friction on the flow. This friction depends on the roughness of the inside surface coming in contact with flow of water.

The laws governing frictional head losses are as follows:

Frictional loss generally increases with roughness of the pipe.

Frictional loss is directly proportional to the area of the wetted surface.

Frictional loss varies inversely as some power of the pipe diameter.

Frictional loss varies as some power of the velocity.

Frictional loss varies as some power of the ratio of viscosity to density of the water.

Friction loss due to water flow through piping systems can be evaluated using various flow coefficients. One such factor is the Hazen-Williams C factor.


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Hazen Williams Equation:

Q = 0.278 CS 0.54 D 2.63

Q in m3/s, D in m, S = H/LV = 1.318 C R h 0.63 S 0.54 (USC Units)

V = 0.849 C R h 0.63 S 0.54 (SI Units)

Where, Rh is the hydraulic radius, S is the head loss per unit length (hf/L), and C is a roughness coefficient associated with the pipe materialFriction loss based on the Hazen-Williams formula is:

f = 0.2083 x (100/C)1.852 x (Q 1.852 /d i 4.8655).

In this formula, the following apply:f = friction head loss in feet of water per 100 feet of pipe;C = constant for inside pipe roughness;Q = flow in US gallons per minute (gpm);d i = inside diameter of pipe in inches

(1 US GPM = 0.227 m3/hr)


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• Value of C would depend upon the roughness only and for any given roughness C would be a constant.

h f = (1.1758 V/CR 0.63 ) x L

Low value of C – means very rough surfaceHigh value of C – means smooth surface

Material Manning (n) Hazen-Williams (C)

Plastic, copper 0.009 160

Concrete - Smooth 0.011 120

Concrete - Design 0.013 100

Corroded Cast Iron 0.020 60

Welded Steel 110

Internally coated Steel 150


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NETRA

Expected life of friction factor at its original value –

Cement mortar lining 5 years

Epoxy lining around 30 years

Thickness of linings –

Cement Mortar lining 30 mm

Epoxy lining 0.50 – 0.70 mm


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NETRAScaling in Heat Exchangers

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NETRA

Pump designed for 630 m3/hr was delivering 450 m3/hr due toSevere fouling. Corrosion products

Losses in Pipes due to Biofouling

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NETRABiofouling & MIC

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NETRASevere Corrosion of CW System

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NETRAControl Measures

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NETRA

Loss of around Rs. 1.2 Crore per 500 MW unit per year

Severe Fouling of PVC Fills

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Heat Rate Improvement = 183 Kcal/kwh

Annual Gain = Rs. 15 Crores

Full Load operation against 80% before cleaning

Restoration of Heat Transfer

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NETRAOther Problems of CW System

80

Eutrefication of reservoir RCC corrosion of Cooling tower structure

Severe foaming at CW Pump and in CW Foreway due to organic contamination

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NETRACondition Assessment of RCC Structures

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NETRACondition Assessment Criteria

S.No. Concrete Design Strength (N/mm2)

Potential (mV Vs Cu/CuS04)

Corrosion Condition

Electrical Resistivity (KiloOhmcm)

Corrosion Condition

1 M - 30 > - 200 Low > 20 Negligible

2 M - 30 - 350 to -200

Intermediate

10 to 20 Low

3 M - 30 < - 350 High 5 to 10 High

4 M - 30 < - 500 Severe < 5 Very High

Condition Assessment Criteria

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NETRACondition Assessment Criteria

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NETRAWater Treatment & Corrosion Issues in Fire Water System

Water Side related issues

Stagnancy of fire water causes depletion of oxygen & chlorine

Microbiological Influenced Corrosion leading to formation of Tubercles & Blockage

Treatment of fire water with microbiocide (chlorine/hypochlorite)

Regular Flushing of Fire water in the system (every fortnight)

Possibility of applying anticorrosive coatings or wherever possible use of HDPE/GRP

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NETRAWater Treatment & Corrosion Issues in Fire Water System

Soil Side issues

Soil causes corrosion of the underground pipelines

Soil characteristics, location, other structures, etc contribute towards corrosion

Bringing the pipelines over-ground wherever feasible

Proper anticorrosive Coatings to be applied

Application of Cathodic Protection for UG Pipelines

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NETRAStructural Corrosion Issues

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NETRAOnline Monitoring of CW Systems

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NETRASome Cases of effect of Organics & Microbiology

96

1. Problem of High Conductivity of DM Water, Condenser tube leakage,Problem of control of boiler tube, tripping of SPU – reason Untreated sewage

2. Biofouling in condenser tubes, microbiologically induced corrosion (MIC)

3. Severe biofouling, scaling & MIC in condenser tubes (loss of generation)

4. Severe biofouling, scaling & MIC in condenser tubes (loss of generation),Problem of non-availability of sufficient DM water, Fouling of PVC fills (stage II)

5. Fouling of PVC fills, Eutrefication of make up water reservoir, pH variation

6. Severe foaming in CW system, (Casuarina tree leaves)

7. Foaming in CW system, Yellow colour in water, choking of NOx filters, Severe biofouling in raw, CW pipelines, HVAC lines, DM feed lines

8. Fouling of PVC film type fills

9. MIC in clarified water pipelines

10. Contamination of water reservoirs resulting in poor quality of make up water

A Maharatna Company

NETRACondenser tube Condition

A Maharatna Company

NETRACorrosion Control & Performance Improvement Options for Cooling Water System

Expected Cooling water quality at different based on Raw water as make up to CW09-10 Maximum

S.No Parameter UnitCycles of Concentration

1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8

1 pH 7.56 9.26 9.89 10.06 10.21 10.33 10.43 10.52 10.6110.6

810.7

510.8

110.8

710.9

2 10.97

2 cond µmhos/cm 1646 2469 3292 4115 4938 5761 6584 7407 8230905

3987

6106

99115

22123

45 13168

3 Turbidity NTU 138 207 276 345 414 483 552 621 690 759 828 897 966103

5 1104

4 CaH ppm as CaCO3 196 294 392 490 588 686 784 882 980107

8117

6127

4137

2147

0 15685 MgH ppm as CaCO3 124 186 248 310 372 434 496 558 620 682 744 806 868 930 992

6 Total hardness ppm as CaCO3 320 480 640 800 960 1120 1280 1440 1600176

0192

0208

0224

0240

0 25607 P alk. ppm as CaCO3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

8 M alk. ppm as CaCO3 336 504 672 840 1008 1176 1344 1512 1680184

8201

6218

4235

2252

0 2688

9 T. alk. ppm as CaCO3 336 504 672 840 1008 1176 1344 1512 1680184

8201

6218

4235

2252

0 2688

10 Chloride ppm as Cl 250 375 500 625 750 875 1000 1125 1250137

5150

0162

5175

0187

5 200011 Shulphate ppm as CaCO3 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640

12 EMA ppm as CaCO3 334 501 668 835 1002 1169 1336 1503 1670183

7200

4217

1233

8250

5 2672

13 Silica ppm as SiO2 18.5 27.75 37 46.25 55.5 64.75 74 83.25 92.5101.

8 111120.

3129.

5138.

8 148

14 Chloride demand ppm 200 300 400 500 600 700 800 900 1000110

0120

0130

0140

0150

0 160015 BOD 72 108 144 180 216 252 288 324 360 396 432 468 504 540 576

16 COD 176 264 352 440 528 616 704 792 880 968105

6114

4123

2132

0 140817 KMnO4 No 54 81 108 135 162 189 216 243 270 297 324 351 378 405 432

PSI 5.39 4.46 3.81 3.30 2.88 2.53 2.23 1.96 1.72 1.50 1.30 1.12 0.95 0.79 0.65

RSI 6.03 3.66 2.56 2.02 1.57 1.20 0.87 0.59 0.33 0.10-

0.11-

0.31-

0.49-

0.66 -0.81

A Maharatna Company

NETRAProblems due to Organic Matter, Microbiolgy Case 1

HIGH ORGANIC MATTER LOADING (UNTREATED SEWAGE) IN RAW WATER:

• Acute problem of obtaining required quality of DM water throughout the year• Problem more severe in summers

• Due to high untreated sewage – proper clarification is very difficult

• Chlorine demand is very high (100 – 200 ppm)

• DM water conductivity goes as high as 0.8 us/cm (4 us/cm in DM tanks)

• pH of Boiler water drops to 7.5 – requires caustic dosing

• High Conductivity water causes deviations in Boiler & Stator water Chemistry

REMEDIAL MEASURES:

• Aeration of the make up water to remove BOD/COD

• Installation of Sewage Treatment Plant prior to clarifiers & Chlorine Dioxide

• Installation of Ultrafilteration system/RO water system prior to DM Plant

• Alternate source of raw water – borewell for DM plant

99

A Maharatna Company

NETRA

100

Analysis of Water SampleWater Extract ( 1gm plant fruit in 500 ml)

Sample COD TOCmg/l mg/l

Extract ( as such)470-500 175-200

Extract after filtration through 0.45 U

270-300 100-125

In the presence of high Organic matter, clarification of water is not effective even with Alum/Polyelectolytes(cationic or anionic)

% ReductionWater Extract ( 1000 ppm solution of plant fruit) 120Water Extract ( 400 ppm solution of plant fruit)

64Water Extract ( 400 ppm solution of plant fruit)+2 ppm KMnO4 56 12.5Water Extract ( 400 ppm solution of plant fruit)+Aeration 48 25

Problems due to Organic Matter, Microbiolgy Case 2

A Maharatna Company

NETRA

101

0102030405060

INTA

KE

R

ES

ER

VO

IR

LIV

E R

ES

ER

VO

IR

DE

AD

R

ES

ER

VO

IR

CLA

RIF

IED

W

ATE

R

CIR

CU

LATI

NG

W

ATE

R

Con

cent

ratio

n in

ppm

Nature of water

TOC, COD & BOD Trend

BOD

COD

TOC 1

TOC 2

Problems due to Organic Matter, Microbiolgy Case 3

A Maharatna Company

NETRA






A Maharatna Company

NETRA

1 2 3 4 5 6 7 8Cycles of Concentration

Cooling Tower Cycles5000 --

4000 --

3000 --

2000 --

1000 --

0

Makeup

Blowdown

RR = 100,000 gpmdT = 20 F

Internal Water ConservationOptimizing COC

A Maharatna Company

NETRA

S.No

COC CirculatingRate m3/hr

DriftM3/hr

EvaporationM3/hr

Blow DownM3/hr

Make upM3/hr

Consumption of Inhibitors l/day

Cost of Inhibitors @ Rs. 33/litreRs/day

5 ppm 10 ppm 5 ppm 10 ppm

1 1.5 32000 160 576 1152 1888 227 453 7476 14953

2 2.0 32000 160 576 576 1312 157 315 5196 10391

3 2.5 32000 160 576 384 1120 134 269 4435 8870

4 3.0 32000 160 576 288 1024 123 246 4055 8110

5 3.5 32000 160 576 230 966 116 232 3827 7654

6 4.0 32000 160 576 192 928 111 223 3675 7350

7 4.5 32000 160 576 165 901 108 216 3566 7133

8 5.0 32000 160 576 144 880 106 211 3485 6970

COC Optimization

A Maharatna Company

NETRA

Evaporation+drift

700 M3/Hr Induced

draft COOLING TOWER

CONDENSER

40000 M3/hr

AUX

Nar

mad

a R

iver

Inta

ke w

ell

MakeUp1100 M3/Hr (Design)800-900 M3/Hr (Actual)

2x275 M3/hr

BLOW DOWN

240 M3/Hr (Design)

190 M3/Hr

DMP Effluent

250 M3/day

Raw Water Pumps for CW

CW Pumps

COC = 4-5

Clariflocculators

STP Effluent

200 M3/day

DM PlantGravity Filter

Clarified water tank

CMB

ClarifierRaw Water Pumps for DM

Plant

3x900M3/hr 2 x 1100 M3/Hr

One Standby

Drinking water

Dis

char

ge to

9

Km

di

stan

ce

275 M3/Hr

Softening plant

RES

ERVO

IR

unlin

ed 3x600M3/hr Softening plant regn waste 3 M3/day

Water Balance

Waste Water Recycling

A Maharatna Company

NETRA

CT BLOW DOWN

5760 M3/Day (Design)

4500 M3/Day

DMP Effluent

250 M3/day

STP Effluent

200 M3/day

Softening Plant

Regeneration Waste

3 M3/day

CMB

Discharge

Effluents discharged from Plant


A Maharatna Company

NETRA

275 m3/hr

Reactor Clarifier 275 M3/hr

GSF

FWST2*150 m3/hr

MB

D/G pumps4*125 m3/hr

FW pumps4*125 m3/hr

3*110 m3/hr

ACFSAC SBA

D/G tank3*55 m3/hr

3*110 m3/hr

3*110 m3/hr

WBA3*110 m3/hr

3*110 m3/hr

Proposed DM Plant Scheme with UF+RO

Effluents

PAC+Chlorine

FeCl3+lime+Dolomite

Proposed UF+RO system

By Gravity


A Maharatna Company

NETRA

Effluent 200 M3/Hr4800 M3/day

Permeate 150 M3/Hr taken as 75%3600 M3/day

Sl. No

Parameter Benefit Amount per month(Rs)

Total Amountper year

(Rs.)

1 Pumping cost to 9 kms 0.6 KWh/M3 @ Rs 3.00/- per KWh 1,94,400.00 23,32,800.00

2 Water Charges on a/c ofCW water

Rs 12.10/- per M3 for 3600 M3daily

13,06,800.00 1,56,81,600.00

3 Cess charges Rs 0.05 per M3 for 3600 M3 daily 5,400.00 64,800.00

4 Makeup water to boiler Improvement in the makeup waterquality will subsequently have lessblowdown rate in boiler.

25000 Approx. 3,00,000.00

5 Regeneration chemicals Rs 5.5/- per M3 5,94,000.00 71,28,000.00

6 life of resins Resin cost savings 5,00,000

7 Pretreatment chemicalsAlum/lime/PAC

Rs 0.25 per M3 27,000.00 3,24,000.00

8 Brine treatment cost Rs 0.10 per M3 14,400.00 1,72,800.00

TOTAL 2,60,04,000.00


Cost Benefit of Recycling

A Maharatna Company

NETRAWaste Water Recycling

Ash Water Recycling

Earlier the Ash to Water Ratio was – 1:13 to 1:15

The Ash slurry is transported to a distance 5 – 15 Km through pipes

The Ash Slurry is collected in Ash Dykes and the decanted water disposed off

Schemes have been developed to recycle the decanted Ash water with suitable Treatment programs and only limited make up is provided to meet the requirements

A Maharatna Company

NETRA






A Maharatna Company

NETRAWater Requirements for Power Generation

A Maharatna Company

NETRATable : Makeup Water Treatment Methods for Removing Impurities Treatment Technologies

A Maharatna Company

NETRAFigure: Effects of Treatment on Raw Water Treatment Technologies

A Maharatna Company

NETRANew Technologies

Adoption of high density Ash Slurry disposal technology

Emphasis on dry ash collection & disposal for ash utilization purposes

Recycling of CW blow down by treatment with UF/RO

Studies on adopting recycling of STP effluents from townships for process water

Setting up of sewage treatment plants for treating organically contaminated water for make up DM and CW systems

Adoption of site specific chemical treatment programs based on commercially available chemicals with optimized COC

Studies on dry cooling systems for extreme scarcity areas

Studies on adopting combinations of technologies like UF/MF, RO, EDI and Ion exchange

Desalinated water at Coastal power plants for sweet water applications

Application of polymeric materials (HDPE/GRP) & Organic coatings for reducing frictional losses in pipes

A Maharatna Company

NETRA

Affordability (New Plant) – NTPC Technology Vision

Technology Drivers

4035

25

7

2009 2017 2025 2032

Water Requirement (Cusec/1000 MW)- Extreme Water Scarcity

40 3525

20

2009 2017 2025 2032

Water Requirement (Cusec/1000 MW)- Business As Usual

NETRAA Maharatna Company

Water Extraction from Flue Gas

Expected Water Recovery from flue gas of a gas station = 95 m3/hr

A Maharatna Company

NETRAPilot Heat Exchanger Installed

Coal power station :Para-

metersunit Flue gas Analysis

ID Fan Outlet of HXe

SOx mg/Nm3 560 152

NOx mg/Nm3 260 215

SPM mg/Nm3 90 52

CO2 % 11.2 11.4

Gas power Station:Sampling point HE Inlet HE outlet

parameter/fuel type unit Natural gasT-gas oC 101.3 35.8T-Air oC 30.1 30.1O2 % 14.17 14.15CO2 % 3.5 3.5CO ppm 1 1NOx ppm 50 50SO2 ppm 0 0

Flue Gas Quality variation due to moisture extraction

A Maharatna Company

NETRAPilot Heat Exchanger Installed

Coal power station:

Parameters unit Value

pH - 2.55

Conductivity µS/cm 2890

Total Hardness

ppm as CaCO3

Nil

Cl ppm as Cl- Nil

M-alk ppm as Cl- Nil

EMA - 1500

Acidity - 450

Quality of Water condensed from flue gas

Gas power Station: PARAMETERS Unit Value

pH - 4.3K µS/cm 213TDS ppm 107Salinity % 0.1Sodium ppm as Na 1Potassium ppm as K 0.7Total Hardness ppm as CaCO3 NilCa Hardness ppm as CaCO3 Nilp-Alkalnity ppm as CaCO3 Nilm-Alkalnity ppm as Cl- NilChloride ppm as Cl- 1Sulphate ppm as SO4

2- 58Nitrate ppm as NO3

- 6

A Maharatna Company

NETRAWater Related R&D – US DOE

A Maharatna Company

NETRAConceptual Design of Liquid Desiccant Process

120

A Maharatna Company

NETRA






A Maharatna Company

NETRARole of Service Providers

Development of less energy intensive technologies for water treatment

Development of Modular treatment technologies requiring lesser space

Improving the performance of RO systems for higher output at lower maintenance

Developing economic treatment technologies/combination of technologies

Improving sewage treatment plants for better output & quality of water for reuse

Developing transparent techno-economic chemical treatment programs

Creation of Institute for improving the quality of manpower & techniques

Developing proper quality & target values for treatment programs

Developing low temperature desalination technologies

A Maharatna Company

NETRA

123

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