Presentation on Benchmarking

8/13/2019 Presentation on Benchmarking

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PRESENTATION ON

BENCHMARKING


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PATH AHEAD

Selection of peer organisations for BBGS plant

We selected Plant Load Factor (PLF) to be the key parameteron which to select the best organisation

A list of Thermal Power Stations were made having PLF greater than 90% in 2003-04. They are :


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PATH AHEAD (Contd)

Name of Station Capacity (MW) State PLF (%) Dahanu 500 (2x250) Maharashtra 98.3

Kothagudem V 500 (2x250) Andhra Pradesh 92.2 GSECL (G5) 210 Gujarat 91.7

GHTP 420 (2x210) Punjab 91.6 Vijaywada 1260 (6x210) Andhra Pradesh 91.3

Mettur 840 Tamil Nadu 91.3 Rihand 1000 Uttar Pradesh 90.6

Rayal Seema 420 Andhra Pradesh 90.3 AE Co 60 Gujarat 90.1

List of Thermal Power Stations having PLF >= 90%


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PATH AHEAD (Contd)

In the list, Vijaywada and Kothagudem V belongs to APGENCO Both Vijaywada and Kothagudem V were consistently winning

prestigious awards presented by the Government of India

Vijaywada Thermal Power Plant has won the Meritorious ProductivityAward for twenty consecutive years and Incentive Award for elevenconsecutive years

Kothagudem Thermal Power Plant V has won the MeritoriousProductivity Award and Incentive Award for four consecutive years

These two plants were selected for initial visits


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Meritorious Productivity Award

An award given by the Government of India against therating given for performance during peak hours

Incentive Award

An award given by the Government of India for Efficient& Economic operation


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Under the category of Meritorious Productivity Awards, the gold medal isgiven to power stations for generation of more than 7500 units/kW/year,the silver medal for generating 7100 to 7500 units/kW/year and bronzemedal for 6600 to 7099 units/kW/year.

Shields are given for generating 6000 units/kW/year or more. These awardsare therefore an indicator of the efficiency of the power plant.

Meritorious productivity awards were introduced in 1983 and are given onfinancial year basis

The incentive scheme for lowering of specific fuel oil consumption andauxiliary power consumption was started in 1992 and is given on calendar

year basis.


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Parameters based on which

the study will be conducted are:


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LIST Main Plant Operation Plant Load Factor

Plant Availability Factor Specific Coal Consumption Specific Oil Consumption Auxiliary % % DM Make-up Unit Outages Combustibles in Ash

Heat Rate Cost of Unit

Fuel and Fuel Handling Plant Maintenance Philosophy Spares Management Environment Administration


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KEY FINDINGS Both the plants are having enviable records of performance

PLF is high in both plants as the demand for power in Andhra Pradeshis more than supply. Seasonal effect is also absent.

PAF is high in both plants (> 95%) because of tight overhaul schedule(12 15 days)

Annual overhaul of units is totally outsourced and is done on job- contract basis

Demurrage paid to railways is almost zero

Combustibles in Fly Ash is less than 0.7% and that in Bottom Ash isless than 4%

Steam Leak Detectors are installed in the boilers of both plants


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Visit to Bakreswar,WBPDCL Visit was also undertaken to Bakreswar Power Plant(3x210 MW) of WBPDCL in West Bengal.Although PAF is greater than 90%, PLF is comparativelylow (78.36% in 2003-04) because of low system demand

The plant has paid zero demurrage to the railways sinceinception in 1999

Combustibles in Fly Ash is between 0.5 to 0.7% and thatin Bottom Ash is between 1 to 2%Steam Leak Detectors are installed in all the boilers ofthe plant


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Visit to Tata Power, Trombay

We next selected Tata Power (Trombay)(150+180+2x500MW) Thermal Power Station

The units run in coal, gas and oil

Unit 5 (500 MW) runs mainly on imported coal but can be runwith oil and gas too


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KEY FINDINGS

Turbine overhaul is carried out wholly byM/s Siemens while M/s UCC carries out theboiler overhaul. The parties themselves hire

all the contract personnel engaged in the job Improvised forced cooling method to reduceoutage hours

Coal is imported from Indonesia


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Improvised forced cooling method

After a forced shutdown (e.g. tube leakage of boiler), the boiler isvented to atmosphere and the drum metal temperature comes downto maximum 110 deg C within 5 hours. This is achieved by keeping theHP & LP bypass of the turbine open while forced cooling by draughtfans is also being carried out. Maximum difference that occurs

between top and bottom drum metal temperature is 70 deg C After about 12 hours of shutdown, when turbine inner casingtemperature is about 370 deg C, the barring gear is stopped,lubricating oil pumps are stopped, jacking oil pump continues to run

and blanking of pipelines to the generator bearings is carried out(process takes about 15 min).The generator is now decoupled from the turbine. During thedecoupling process, hand barring is being done regularly. By this

process, the generator overhauling job can be start from the second

day itself, thereby saving time.


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Outstanding practices After the visits, following actions were aimed to beimplemented in Budge Budge Generating Station :

Reduction in Demurrage paid to the railways

Reduction in Combustibles in Fly and Bottom Ash Installation of Tube Leak Detection System


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REDUCTION IN DEMURRAGE STEPS TAKEN

A time study of the coal unloading operation

National Productivity Council was entrusted with the job.SUBSEQUENTLY

For BOBR rakes : Tare weighment discontinued in line with the loading end.Manpower for unloading was increased

2 shunting engines hired to decrease time for shunting of wagons

Coal flow during unloading was increased by running two chains

Incentive scheme introduced for unloading of BOX N rakes


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IMPROVEMENTS

BOBR BOX N BOBR BOX N 2003 - 04 265 348 3.75 13.42 2004 - 05 313 340 4.06 13.63 2005 - 06 411 334 2.79 10.70

Number of Rakes Average Unloading

Time (Hrs)


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IMPROVEMENTS

BOBR BOX N BOBR BOX N 2003 - 04 265 348 3.75 13.42 2004 - 05 313 340 4.06 13.63 2005 - 06 411 334 2.79 10.70

Number of Rakes Average Unloading

Time (Hrs)

Real decrease in Average Unloading Time observed in 2005-06when all the steps discussed before were implemented


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REDUCTION OF COMBUSTIBLES IN

ASH

The average figures for combustibles in Fly and Bottom Ash in ourbenchmarked stations was 0.7 & 4% respectively But this was for Tangential firing boilers

No data was available for Double Down Shot type boilers

So it was decided to benchmark the Design Heat Loss figure of2.5% as stated by OEM in their design considerations


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REDUCTION OF COMBUSTIBLES IN

ASH

STEPS TAKEN

Optimisation of Boiler Total Air Flow for maximum

efficiency

Implementation of Boiler Auto Combustion Control for proper distribution of Primary & Secondary Air


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IMPROVEMENTS

Fly Ash Bottom Ash 2003 - 04 3.96 8.91 2004 - 05

2.65 8.79 2005 - 06 2.13 6.26

Combustible % in


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IMPROVEMENTS

Fly Ash Bottom Ash 2003 - 04 3.96 8.91 2004 - 05 2.65 8.79 2005 - 06 2.13 6.26

Combustible % in


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INSTALLATION OF TUBE LEAK

DETECTION SYSTEM

Boiler Tube leak detection system based on Acoustictechnology have been installed in one unit of BudgeBudge Generating Station. Installation in the otherwill be done after checking the effectiveness of thisone.


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Visit to Dahanu,Reliance Energy

Dahanu (2x250MW) Thermal Power Station of RelianceEnergy Ltd

Dahanu was selected as one of the Top Plants of the World 2004 by platts Power, USA amongst 12 short listed power

plants

For FY 2004-05, its PLF was 101.35% (a feat unequalled till

date), Loading Factor 104.61% and Auxiliary 7.53%


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KEY FINDINGS Plant Load Factor greater than 100%

Loading Factor more than 100% (achieved by running the T/Aat 262 MW with name plate capacity of 250 MW)

Auxiliary % was only 7.53

Statutory Overhaul of Boiler carried out in 12 15 days,Turbine overhaul is contracted out to BHEL

Coal stock maintained > 3.5 lakh Te (1.8 lakh Te washed coalfrom Korba and 1.7 lakh Te imported coal)


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Benchmarking BBGS, CESC Limited and Dahanu, Reliance Energy

BENCHMARKED PERFORMANCE FIGURES

PLF to be 100% PAF to be > 95 %Auxiliary power consumption to be 7.5%

Statutory Overhaul period for boiler to be completedwithin 11 days in phases Minimum ground coal stock 1.0 Lakh tonnes


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INCREASE OF BBGS PLF TO 100%

To achieve this, BBGS units have to be operated at a loadmore than its rated capacity of 250 MW 262 MW wasdecided as all technical parameters remained within limits

at that load Statutory overhaul period will have to be limited to 1215days

Seasonal as well as daily variation of load in CESCs system will have to be flattened out through increasedexport of power


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INCREASE OF BBGS PAF

Forced outages of units have to be minimum

Statutory overhaul period will have to be limited to 1215days Necessary planning of survey activities from freshangle and procurement of sky-climber may facilitate this


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IMPROVEMENTS IN PLF & PAF

PLF (%) PAF (%)

2003 - 04 79.85 91.73

2004 - 05 86.40 92.74

2005 - 06 99.61 97.47


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IMPROVEMENTS IN PLF & PAF

PLF (%) PAF (%)

2003 - 04 79.85 91.73

2004 - 05 86.40 92.74

2005 - 06 99.61 97.47


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IMPROVEMENTS IN PERIOD OF

OVERHAUL

PERIOD OF STATUTORYOVERHAUL (DAYS)

2003 - 04 30.6 2004 - 05 30.7

2005 - 06 11.3


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REDUCTION OF BBGS AUXILIARY% PLF will have to be increased to 100%

Forced outages of units have to be minimum Dahanu has open circuit cooling system whereas BBGS havecooling towers.

Dahanu has wet Fly Ash Conveying System whereas BBGS havedry Fly Ash Conveying System

these inherent differences in design restricts BBGS from

reaching Dahanus level of Auxiliary% Various options to reduce auxiliary will have to be explored


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REDUCTION OF BBGS AUXILIARY% STEPS TAKEN

Reduction in Differential pressure across Feed ControlStation led to lower BFP discharge pressure and lowerspeed. Hence a reduction in power consumed is effected.

Logic modification carried out in ID Fan Vane Controlwith speed. The suction vane now opens more in the sameload thus causing lower speed and lower powerconsumption.

Service Air pressure is reduced from 7 kg/sq cm to 6kg/sq cm. As a result one compressor is now enough tosupply the whole requirement compared to two before


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IMPROVEMENTS IN AUXILIARY %

Auxiliary (%)

2003 - 04 9.04 2004 - 05 8.69 2005 - 06 8.32


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IMPROVEMENTS IN AUXILIARY %

Auxiliary (%)

2003 - 04 9.04 2004 - 05 8.69 2005 - 06 8.32


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Indian Thermal Power Plants (Source CEA)

Presentation on Benchmarking

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