Energy Consevation in Power Plants

7/29/2019 Energy Consevation in Power Plants

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PRESENTATION OUTLINE

Potential areas in power plants for energy

saving

Waste heat areas & utilization


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Energy saving Opportunity in

Thermal Power plant

In any thermal plant normally 30-

40 % fuel energy is converted into

electricity and rest is wasted in

various processes of generation,

distribution or transmission with

heat loss as major loss


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Thermal Power plant

Air and flue gas cycle

Furnace

Steam cycle

Fuel and ash cycleFeed water/condensate cycle

CW /ACRW cycle

Compressed air system

Refrigeration & HVAC

Miscellaneous system


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Energy saving Opportunity in Thermal

Power plant

Air and Flue Gas Cycle

Optimising Air Fuel ratio. A 10% drop in

excess air amounts to 1% saving of fuel infurnaces

Replacement of oversize fans

Attending air and flue gas duct leakages


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Energy saving Opportunity in Thermal

Power plant

Furnace

Reduce heat loss through furnace openings.

Observations show that a furnace operating at a temp.of 10000C having an open door (1500 mm X 750 mm)

results in fuel loss of 10 lit/hr. For a 4000 hrs. furnace

operation this translates in to a loss of approx. Rs. 4

lakhs per year.


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Thermal Power plant

Feed water / steam cyclePracticing of scoop control instead of pcontrol

Optimising of HP/LP heater level

Charging of APRDS from CRH

Monitoring of recirculation valve passing

Installation of VFD on partially loaded drives


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Thermal Power plantFuel and Ash Cycle

Proper maintenance of mills and replacement

of mill internalsOptimum loading of mills

Use of high CV coal wherever available

Avoiding idle running of conveyers & crushers

Use of dry ash evacuation instead of wet ashOptimising ash water ratio


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Thermal Power plant

Electrical & Lighting systemOptimising voltage level in DTsReducing voltage of lighting transformers

Use of electronic ballast in place ofconventional choke saves energy upto 20%.

Use of CFL lamp in place of GLS lamp cansave energy upto 70%.


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Thermal Power plant

CW/Aux CW System

Isolating standby equipmentsImproving condenser performance

by proper cleaning of tubes and

water conditionSome innovative measure as

polymer coating on pump internals


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Thermal Power plant

Refrigeration & HVAC

Utilise waste heat of excess steam or flue gases to change

over from gas compression to absorption chilling system and

save energy costs in the range of 50- 70%.

Proper maintenance of equipments as

CT , chillers and condensers etc. for proper heat exchange. A

50C decrease in evaporator temp. increases the specific power

consumption by 15%.

Use of wind turbo exhauster.


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Thermal Power plant

Compressed Air

systemOptimising air dischargepressure

Use of screw compressorsinstead of reciprocatingcompressors


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NATIONAL AND INTERNATIONALBENCHMARKS

PLANT AUXILIARY POWER CONSUMPTION IS

THE MOST IMPORTANT PARAMETER THAT

SHOULD BE TAKEN UP AS E. C. ACTIVITY

A BENCHMARK OF APC FOR A 500 MW UNIT

WOULD BE AROUND 5%

BENCHMARK OF APC FOR A 200 MW UNIT MAY

BE TAKEN AS 7%

CORRESPONDING BENCHMARK FOR A 660 MW

UNIT IN INTERNATIONAL PLANT WOULD BE

3.66%


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Thermal Power plant

Installation of On Line Energy

management system for major drives

Installation of back pressure turbine


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Certain Startling Facts

Loss of even one drop of oil every second can

cost you over 4000 litres a year

An uncovered flange is equivalent to leaving 0.6

meter of pipe line un-legged. If a 0.15 m steampipe diameter has 5 uncovered flanges, there

would be a loss of heat equivalent to wasting 5

tons of coal or 3000 litres of oil a year


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Every 4o C rise in inlet air temperature of a

compressor results in a higher energy

consumption by 1 % to achieve equivalent

output For every 250 mm WC pressure drop increase

across the suction path due to choked filters

etc., the compressor power consumption

increases by about 2 % for the same output


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An increase of 5.5o C in the inlet air temperatureto the second stage of compressor results in a 2

% increase in the specific energy consumption

A reduction in the delivery pressure by 1 bar in a

compressor would reduce the power

consumption by 6 10 %

A leakage from a dia hole from a compresses

air line working at a pressure of 7Kg/cm2

candrain almost Rs. 3000 per day.


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Keep compressor valves in good condition by removingand inspecting once every six months. Worn-out valvescan reduce compressor efficiency by as much as 50percent.

Consideration should be given to two-stage or multistagecompressor as it consumes less power for the same airoutput than a single stage compressor.

If pressure requirements for processes are widelydifferent (e.g. 3 bar to 7 bar), it is advisable to have two

separate compressed air systems


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Replacement of metallic or Glass fibre

reinforced plastic fan blades with efficient

hollow FRP blades, have given resultant

fan energy savings of the order of 20-30%and with simple pay back period of 6 to 7

months


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Therefore

A systematic and well documented energy

audit of any subsystem will give the plant

engineer a plan through which he can

effectively manage the plants energysystem and significantly reduce the plants

energy costs


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Documents

Energy Consevation in Power Plants