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M A PatilSr. Director

FICCI - Resource Conservation & Management GroupEmail: ma.patil@ficci.com

Water Optimisation –

A Project Showcase -

Based on Water Audit study in a power plant

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About FICCI FICCI is the largest and oldest apex business organization in India

established in 1927 as not for profit organization. FICCI is the voice of India’s business & industry having its

presence through nation-wide membership of about 1500 corporate & Associate members + 500 chambers of commerce & business associations (representing over 250,000 industries) .

FICCI has been a catalyst in empowering Indian businesses, in the changing times, to shore up their competitiveness & enhance their global reach.

FICCI is working for more than 50 sectors of economy Strength of over 400 employees across the country & aboard with

13 states offices within India 10 International offices-USA, Germany, France, London, etc

Services Offered by RCM Group, FICCI

Technical consultancy

Services

Industrial Audits (Water and Energy)

National level studies for Government/Multilateral Agencies

International Consultancy projects

Capacity Building Workshops/Conferences

Demonstration projects for SMEs/Clusters

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Areas : Energy, Water & Environment Management

FICCI WATER MANAGEMENT STUDIES

• Cement• Iron & Steel• Beverage• Pulp & Paper• Pharmaceuticals• Zinc• Power plants

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• Textiles• Chemical• Oil & Refinery• Aluminium• Sugar• Building ComplexOther sectors

Done water audit studies for more than 100 industrial units

IISCO-ISP, ITC, NTPC, IOCL, BPCL, BALCO, EssarSteel Ltd, JK Lakshmi Cement, UltraTech Cement, UBGroup, Coca Cola India Inc, HZL, ACC Ltd etc- sectors :

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Water Audit – A useful tool to achieve Water Optimisation

Several Benefits of FICCI conducted Water & Wastewater Audits

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WATER AUDITS: POTENTIAL BENEFITS

Reduction in specific water consumption.Reduced Pumping/Distribution & water treatment costsBetter Utilization of Water within the plant

- through Reuse, RecyclingReduced consumption/wastage of other raw materials

- process cost / production costReduction in effluent generationReduced Wastewater / Effluent Treatment Cost

- land, capital, chemicals, energy and labor costsReduced Legal LiabilityReduced incidence of production losses due to increased

water availabilityBetter Safeguard to Public Health & Property

How water audit helps?

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Typical SCOPE OF WORK

• Development of Water Circuit Flow Diagram for the entire complexshowing locations of reservoir tanks and pumps etc.

•Collection & compilation of basic data of pumps rateddetails, operating hours of pumps, reservoirs/tanks capacities etc.

•Measurements of Flow, Pressure and Power at major operatingpumps

•Performance Assessment of Pumps, cooling towers etc, in terms ofactual v/s rated efficiency & Identification of inefficient pumps

•Preparation of Water Balance Diagram

•Study of existing Water Distribution system & Estimation ofassociated losses

• Study for optimization of fresh water usage at variousconsumption points and recommend cost effective schemes

• Evolving value added “cost of water” at various locations

• Assessment of water usage for Utilities

• Identification of consumption of existing sub meter and thedistribution of water under various sections

• Evolving recommendations on water conservation & costreductions

• Suggestions for reduction, reuse, recycling, regeneration& recharging options for water conservation With costbenefit analysis and the required investment.

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Typical AUDIT SCOPE OF WORK (Cont.)

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• Assessing the logistics of existing water managementpractices & suggesting appropriate changes for reducingoverall costs & improved water management.

• Incorporating latest water conserving equipments/technologies in recommendations.

• Provide details on Rainwater Harvesting (RWH)potential for the given site and suggest possible RWHschemes.

•Evolving WATCON (Water Conservation) options with itstechno-economic feasibility aspects & Cost BenefitAnalysis.

ADDITIONAL SCOPE – recommended by FICCI

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OverheadTank WTP

Process

Cooling

Domestic etc.Filtered water

DM Water

Soft water

a

a+b

a+2b

a+3b+c

a+3b+2c

a+3b+3c

a – cost of raw water b- pumping costc- treatment cost

How to decide Cost of Water ?

Water Consumption Areas in Power Plants

– Cooling Tower (for Condenser cooling, other) – Ash handling system (for wet ash)– Power cycle make up water– Coal dust suppression system – Service water – Potable water – Landscaping, Gardening– Evaporation from raw water reservoirs etc_ Domestic water (for colony).

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Typical Water Consumption FiguresPlant water consumption governed by a number of factors :

– Quality of raw water,– type of condenser cooling system,– Quality of coal,– Ash utilization,– Type of ash disposal system– Wastewater management aspects etc.

• In past, power stations were designed with water systemshaving liberal considerations and high design margins.

• The consumptive water requirement for coal based plantswith cooling towers used to be about 7 m3/h per MW

• In recent times, plants have been designed with reduced Plantwater consumption rate in the range 3.5 ‐ 4 m3/h per MW

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Specific Water Consumption of a Coal Based TPP in India

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Recent MoEFCC Notificationdated December 07, 2015 on Environment (Protection) Amendment Rules,2015 have notified the following:

I. All plants with Once Through Cooling (OTC) shall install Cooling Tower(CT) and achieve specific water consumption up to maximum of 3.5 m3/MWhwithin a period of two years from the date of publication of this notification.

II. All existing CT‐based plants shall have to reduce specific waterconsumption up to maximum of 3.5 m3/MWh within a period of two yearsfrom the date of publication of this notification.

III. New plants to be installed after 1st January, 2017 shall have to meetspecific water consumption up to maximum of 2.5 m3/MWh and achieve zerowastewater discharged.

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FICCI WATER AUDIT project CASE STUDY – Gas based

Power Plant

Water Scenario:

Main Raw Water Source – Surface Water (GurgaonCanal)

Total Raw Water pumping from Canal = 1260 m3/day

Total Raw Water Use = 13,800 m3/day

Water Treatment Scheme = Clarification, Sedimentationand Gravity Sand Filtration

DM Water Generation = 280 m3/day (Dec. 2009)

Cooling Tower Make Up = 11400 m3/month

Water Use Pattern

Cooling Water

Make Up83%

Plant Drinking

Water3%

Service Water

8%DM Water

6%

Water balance Diagram of the plant:

FIELD MEASUREMENTS CONDUCTED

Measurement Locations:Water Source side measurements , at: Canal Water pumps

Distribution side measurements , at : Raw Water Pump House - Clarifier PumpsCooling Water Make Up Cooling Towers Pumps Cooling Towers – Uprisers, Common Header Output DM Plant – Filter Water Transfer Pumps DM Plant – Degassifier Pumps DM Plant – Regeneration Pumps Fire Water Pumps Tube Well Pumps Condenser Line Input Condenser Line Output

Actual field measurement detailsLocation/Pump Pump No. Water Delivered To Power KW Flow PressDescription Actual m3/hr m

Canal Raw Water Pump

RWC Plant Reservoir 97.5 1260.0 17.0RWB 117.2 1336.0 20.0

Cooling Water RW Pump

P4A Clarrifier 35.4 576.0 6.5P4B 35.8 588.0 7.0P4C 36.7 574.0 6.0

PT Raw Water Supply Pump

P3A PTPlant 17.3 128.5 23.5P3B 17.5 131.0 24.0P3C 16.6 137.0 23.5

Filter Water Transfer Pump( DM Plant)

P1A DM Plant 27.8 107.0 34.5P1B 24.9 96.5 38.0P1C 27.5 99.0 32.0

Degassifier Water Pump

P2A DM Storage 39.6 100.0 36.0P2B 34.9 101.0 41.0P2C 34.4 102.0 39.0

Regeneration PumpsP3A SAC, WAC 1.6 50.0 5.6P3B 1.7 70.0 5.8

CT Make Up Water Transfer Pumps

A Cooling Towers 25.7 520.0 9.5B 25.2 581.0 11.5

CW PumpsCWP-A Cooling Water in Process 1180 13800.0 22CWP-B 1188 12375.0 24.2CWP-C 1190 14200.0 22.8

Blow Down PumpsBDP/P1 Blow Down 8.6 75.0 11.0BDP/P2 10.9 106.0 14.0

Tube Wells Pumps

2.0 Plant & ADM Building 12.6 41.7 401.0 DM Plant 12.7 22.4 393.0 DM Plant 18.1 45.3 46

Filter Back Wash PumpsA Steer Chamber 5.8 27.0 20.5B Steer Chamber 6.2 28.3 9.5

Case study focus :

• 1. Clarifiers – improving efficiency of clarification

• 2. Condenser Cooling Tower (Major water consumer) – improving cooling performance of CT

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Measurements taken for CT:Location

Water Delivered to Flow, m3/hr

Condenser Input Line Condenser Cooling 12,500 – 13,650

Condenser Output Line Cooling Tower 12,300 – 13,600

Cooling Tower cells

Upriser 1 1089Upriser 2 980Upriser 3 1274Upriser 4 1054Upriser 5 1132Upriser 6 1180Upriser 7 1367Upriser 8 1142Upriser 9 1298Upriser 10 1223Upriser 11 1276Upriser 12 1098Upriser 13 1321Upriser 14 1235Upriser 15 1256Upriser 16 1380Upriser 17 1054Upriser 18 1070

Common Header to CT 24200Common Header for 9 CT (Left Side) 12789

Common Header for 9 CT (Right Side) 11400

A few Water Audit Observations &

Interpretation – to evolve water

conservation options

Under-use of available Clarifiers:2 clarifiers available; only one is operated at a time. Design Capacity of each Clarifier = 720 m3/hr.Operational capacity = 575-600 m3/hr.input water turbidity = 80 NTU, which is reduced to 40NTU by clarification process. After clarification the water is filtered in the GravitySand Filters (GSF), where the turbidity get furtherreduced to 15 NTU. The filtered water is stored in the filter sump fromwhere water is pumped to the cooling tower basin asmake-up water.

Schematic of Existing Water Clarification System:

WATCON RecommendationStart Parallel use of both the Clarifiers to achieve Lower Turbidity:

Operate both the clarifiers simultaneously with reduced hydraulic loading of about 450 m3/hr in each clarifier, instead of operating only

one clarifier with hydraulic loading of about 600 m3/hr. Reduced hydraulic loading in each clarifier, would increase retention

time for the settling particles in the clarifiers and hence would have higher efficiency.

It is expected that the turbidity from 80 NTU would reduce to 5-10 NTU (as shown in figure)

Existing scheme Proposed Scheme:

The proposed scheme would benefit the unit in terms of:

Improved efficiency of Sand bed Filters due toreduced turbidity of clarified water Increased COC in the cooling Towers due toreduced turbidity in make-up water Decreased effluent generation due to lesserblow downs in cooling towers reduced dependency on groundwater formaking demineralized water

Cooling Towers: The cooling Towers are one of the importantsections in the unit with respect to water use. The cooling Towers accounts for about 83% oftotal water use in the unit. The unit has 3 nos. of pumps for pumping hotprocess water to process cooling area. From process cooling area the hot water is sent toCooling Towers for cooling through a main header. The flow in the main header is about 24,200 m3/hr. The existing CT has total 18 no. of CT cells; 9 evennumbered cell and other 9 odd numbered cell

Observations at Cooling Towers:

Distribution of hot process water is not uniform ineach CT cell and has large variations from the averageflow values. The average flow rate in odd and even numbered cellsis calculated as 1227 m3/hr and 1142 m3/hr.Most of the CT cells are receiving either less flow ormore flow than the average flow rate. Some of the CT cells are observed to be receiving theflow rate as high as 1380 m3/hr and as low as 980 m3/hras shown in figure.

Locations of measurements at Cooling Towers

Cooling Water Flow Distribution to 18 cells

1089

1274

1132

1367

12681276

1328

1256

1054

980

1054

11801142

1223

1018

1235

1380

1070

800

900

1000

1100

1200

1300

1400

1 3 5 7 9 11 13 15 17 2 4 6 8 10 12 14 16 18

flow

in c

u. m

/hr

odd cells even cellsUpriser Branch Water Division

% flow variation in Cells:

Recommendation to improve CT performance

Ensure Uniform Water Flow Distribution in all 18cells of, by adjusting/setting flow Control valves, toget optimum performance of Cooling Tower : The percentage deviation of the hot process water distributionin most of the CT cells is > +10 % than the average flow rate. The cells receiving higher flow rate are expected to havereduced cooling, increased drift losses, and overall low efficiencywhereas the cells receiving lower flow rates would remain underutilized. Therefore, it was suggested that the unit should regulate equalflow rates in each CT cell so as to achieve higher coolingefficiency and optimum utilization of the Cooling Tower cells.

The flow should be equal in all the cells to prevent the driftloses and optimum utilization of CT. This can be achieved by adjustment in setting of valves ineach cells so that the flow is equally distributed and regulated.

The flow variation up to +5% is acceptable. Out of the total18 cells, 6 cells have variation in the range of 5 to 10% range.For optimum performance of the cooling towers, the flowdistribution should be as uniform as possible, within 5%variations. This would benefit in terms of increased cooling effect &increased overall efficiency of cooling towers.

Benefits Achieved

– T increases by 1-2 oC and increased vacuum which ultimately increases power generation in the plant (reported to be about 1-2% by the plant)

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Adopt Rainwater Harvesting The unit had implemented RWH to certain extent, it wasobserved that the present RWH system is not very efficient. The unit has four recharge pits, two are located within thepremises of the unit and another two are located in thetownship. The 2 nos. recharge pits in the unit are designed to rechargeground water in rooftop runoff. It was also observed that the bore well no. 1(near DM plantstorage tank) has very low yield, about < 40 % of its ratedcapacity

Catchment/Area details of the Plant:

The total area of the unit is reported to be about 8, 98,403meter Square (222 Acres). About 26% of total plant area is covered under green belt,about 67% is open area, 4.5% is under reservoir and about 2.3%under building roof-top area.

Estimation of RWH Potential The rainwater harvesting potential considering roof-top andopen area (paved and unpaved) of the plant is about 77,408 m3per year. The unit can store the rainwater in the available reservoirs fordirect use and remaining water can be artificially recharged togroundwater through recharge pits, trenches or using percolationpits.

S.No.

CatchmentDetails

Area (Sq. meter)

Permit area* (Sq.

meter)

Avg. Rainfall/ Year (m)

Runoff coefficien

t

RWH Potential

(m3)

1 Roof-Top Area 20234 14164 0.564 0.75 5991

2 Open Area (Paved/ unpaved/ Green)

602982 422087 0.564 0.2-0.5 71417

Total RWH Potential (m3) 77408

Recommendation:Implementation of Rain Water Harvesting

Scheme to Recharge Ground Water: It is also observed that the bore well no. 1(near DMplant storage tank) has very low yield, about < 40 % of itsrated capacity Therefore it is suggested that this bore well should beconverted into recharge pit for recharging of ground waterin rooftop or surface water collection in monsoon. To clean the catchment area (rooftops) is also veryimportant for effective rainwater harvesting. The cleaning of catchment area improves the quality ofwater and rain water can be directly used for domesticpurposes.

The existing recharge pit requires propercleaning and maintenance.The filter media needs to be washed and desiltedof pits is required.Without cleaning and maintenance there may bechances of choking and overflow of recharge pits.The existing bore wells have minimum yield.These bore wells can be used as recharge pits toincrease water level of the ground water for future. The converting existing bore well into rechargepits will be less expensive than to construct newrecharge pits.

Methodology for Determination of Pump Efficiency:

Based on the three measurements (flow, power & pressure),the combined pump efficiency can be computed by usingfollowing formula:Hydraulic Power = Q (m3/sec) x x 9.81x H (mWC)Shaft Power = Motor Input Power x Motor EfficiencyPump Efficiency = Hydraulic Power/Shaft PowerWhere:Q=Water Flow rate in m3/sec

=Specific Gravity (1.0 for water)H=Total Head developed (m of water column),

Discharge-SuctionKW=Actual power consumed at motor input.

a. Analysis of Raw Water Pumps – (Clarifier Pumps):

In order to match the clarifier capacity, the flowis regulated through an automatic throttling system,such that the flow is about 575 m³/hr. Due to throttling, it has been found that, there issubstantial loss of energy

Recommendation:Use of Variable Speed Drive instead of existing throttling flow

control for Raw Water Pumps:

“throttling” is not the best way to control the waterflow, as it leads to substantial loss of energy. Instead either a variable speed drive should be used orthe pump should be replaced with desired head and flowas per actual requirement of the clarifier flow.

b. Analysis of Filter Water Transfer Pumps –DM Plant:o Presently 3 nos of 30 KW pumps have beeninstalled in PT plant.oThe water is pumped to the DM plant as per waterrequirement.

Recommendation for Pumps:

Replacement of Less Efficient Pumps:

o Several pumps operating at lower efficiency thanrated efficiency.o But considering their limited use in a year (forabout 1460 hrs/year), the loss of energy due to lowerefficiency is not substantial.o If pumps need to be operated continuously, thenthe option of replacement of these pumps could beconsidered.

Actual Measurements of Pumps:Location/Pump Pump No. Water Delivered To Power KW Flow Press Actual PumpDescription Actual m3/hr m Eff(%)Canal Raw Water

PumpRWC Plant Reservoir 97.5 1260.0 17.0 70%RWB 117.2 1336.0 20.0 73%

Cooling Water RW Pump

P4A Clarrifier 35.4 576.0 6.5 34%P4B 35.8 588.0 7.0 37%P4C 36.7 574.0 6.0 30%

PT Raw Water Supply Pump

P3A PTPlant 17.3 128.5 23.5 56%P3B 17.5 131.0 24.0 58%P3C 16.6 137.0 23.5 62%

Filter Water Transfer Pump(

DM Plant)

P1A DM Plant 27.8 107.0 34.5 43%P1B 24.9 96.5 38.0 47%P1C 27.5 99.0 32.0 37%

Degassifier Water Pump

P2A DM Storage 39.6 100.0 36.0 29%P2B 34.9 101.0 41.0 38%P2C 34.4 102.0 39.0 37%

Regeneration Pumps

P3A SAC, WAC 1.6 50.0 5.6 56%P3B 1.7 70.0 5.8 79%

CT Make Up Water Transfer Pumps

A Cooling Towers 25.7 520.0 9.5 62%B 25.2 581.0 11.5 85%

CW Pumps

CWP-A Cooling Water in Process

1180 13800.0 22 82%CWP-B 1188 12375.0 24.2 81%CWP-C 1190 14200.0 22.8 87%

Blow Down Pumps BDP/P1 Blow Down 8.6 75.0 11.0 31%BDP/P2 10.9 106.0 14.0 44%

Tube Wells Pumps

2.0 Plant & ADM Building 12.6 41.7 40 42%1.0 DM Plant 12.7 22.4 39 22%3.0 DM Plant 18.1 45.3 46 37%

Filter Back Wash Pumps

A Steer Chamber 5.8 27.0 20.5 31%B Steer Chamber 6.2 28.3 9.5 14%

Possible Recycling options for Reduction of SWC in TPP

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Detailed Water Audit study for the above options needs to carried out before adoption.

Conclusion

• Power Plants have significant potentialto reduce its Specific WaterConsumption,

• along-with improvement inproductivity and cost savings,

• which needs to be achieved throughdetailed Water Audit Studies

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M A PatilSr. Director

FICCI - Resource Conservation & Management GroupEmail: ma.patil@ficci.com

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