Download - Thermal Power Plant Auditing
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PRESENTATION ON ESSENTIAL REQUIREMENTS
FOR
ENERGY AUDITS
IN
THERMAL POWER STATIONS
BY
H.S.BediSr. Vice President (Power)
Energo Engineering Projects Ltd.A-57/4, Okhla Industrial Area,Phase – II, New Delhi - 110020
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““You cannot Manage what you You cannot Manage what you cannot Measure”cannot Measure”
(Accurately)(Accurately)
- Jack Welch, CEO, General Electric- Jack Welch, CEO, General Electric
PATTERN OF ENERGY CONSUMPTION
IN
THERMAL POWER STATION
4TYPICAL PLANT LOSSES
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SHORT FALL LOSS IN CRORES PER ANNUM
TURBINE CYCLE HEAT RATE 1.0 % 5.0
BOILER EFFICIENCY 1.0% 1.75
AUX. POWER CONSUMPTION 5.0 % 1.25
ECONOMIC ASPECTS OF INEFFICIENT
MACHINES (200 MW)
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REQUIREMENT – 1
1.1 ACCURACY OF COLLECTED DATA
– Collected data has to be most accurate & doubtless.
– Use calibrated and accurate instruments better conforming to ASME-PTC
standards
– 1.0% Error in data means unreliability and 25000 tons of coal loss/annum for
200 MW Unit or approx Rs. 5 crores / year based on assumption that
•TG cycle heat rate is taken as 2000 kcal / kwh
•Coal CV is taken as 4000 kcal / kg
•Price of coal taken as Rs. 2000 / ton
– Loss increases with machine size
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1.2 EFFECT OF INSTRUMENTATION ON ACCURACY
A. Plant on-line instruments with few audit instruments Accuracy around 3.0%.B. Accurate calibrated instruments as per ASME-PTC-6 for steam turbine& ASME-PTC-4-1 for Boilers. Accuracy around 0.5 %
1.3 EFFECT OF PROCEDURE ON ACCURACY OTHER THANASME-PTC-6 for steam turbines and ASME – PTC-4.1 for boiler
– Error in Boiler Energy Audit – around 2.0%– Error in steam turbine Energy Audit – around 3.0%
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1.4 TOTAL ERROR BECAUSE OF
INSTRUMENTATION & PROCEDURE
INACCURACY 6.0%
NOTE:DIFFERENCE IN COST OF ENERGY AUDIT BETWEEN AUDIT BY ACCURATE INSTRUMENTS AS PER ASME AND NORMAL INSTRUMENTS IS 12 TO 14 LACS AS AGAINST 6 TO 8 LACS.
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EFFECT OF INSTRUMENT INACCURACY ON HP/IP Turbine Efficiency
HPT Efficiency
Main Steam HPT ExhaustPressureKg/cm2
TempDeg C
PressureKg/cm2
TempDeg C
1 1 1 10.6 % 0.6 % 2.0 % 0.7 %
IPT Efficiency
IPT Inlet IPT ExhaustPressureKg/cm2
TempDeg C
PressureKg/cm2
TempDeg C
1 1 1 11.2 % 0.3 % 6.0 % 0.4 %
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EFFECT ON HEAT RATE FOR PARAMETER DEVIATION (500MW UNIT)
DEVIATION IN PARAMETER EFFECT ON HEAT RATE (KCAL/KWH)
1. HPT inlet press. by 5.0 ata 6.25
2. HPT inlet temperature by 10.0deg C 6.0
3. IPT inlet temperature by 10.0deg C 5.6
4. Condenser pressure by 10.0 mm of Hg
9.0
5. RH spray water quantity by 1.0% 4.0
6. HPT Cylinder efficiency by 1.0% 3.5
7. IPT Cylinder efficiency by 1.0% 4.0
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REQUIRED ACCURACY AND CALIBRATION OF THE INSTRUMENTS The proposed instruments should have following level of accuracy.
i. Thermocouples and PRTs – ASME special class ‘A’ i.e ½ DIN tolerance ii. Pressure and differential pressure - 0.1% transmitters better thaniii. Power Meter for generator & - 0.1%
Unit Aux Power measurementiv Data Logger - 0.03%v Power transducers / Load Analyser - 0.5%vi Flue gas analyser - 0.5%vii Ultrasonic flow meters - 0.5%viii Anemometer - 1.0%ix Infrared Thermometer - 1.0%x Lux meter - 1.0%xi RH meter - 1.0%
These should be duly calibrated from NABL accredited lab.The above accuracies for S.No. I to V are as per ASME specified for
Performance Evaluation of Thermal Power Plants.
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Economizer
FG
APH
SamplingLocations
FG
APH
ExpansionBellow
HVS
REQUIREMENT – IIPROPER SCHEMES FOR ENERGY AUDIT
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Annexure - IBOILER EFFICIENCY AND APH TEST SCHEME &
INSTRUMENTATION DIAGRAM 1. Grid measurement for gas composition and gas temp. at air pre heater inlet / outlet.
W/6 W/3 T1
W/3 T2
W/6 T3
N11 N21 N31
D/6
N12
N22 N32
D/3
N13 N23 N33
D/3
D/6
DEPTH
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ENERGY AUDIT SCHEME FOR 210 LMW STEAM TURBINE
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TURBINE CYCLE AUDIT
Pressure - 5 MinutesTemperature - 5 MinutesFlow - 1 MinutePower - 1 MinuteLevels - 10 Minutes
BOILER UNIT AUDIT
Temperature - 15 to 30 MinutesFlue Gas Composition - ½ to one hour
DURATION OF AUDIT TEST
Turbine Cycle - 2 HrsBoiler Unit - 4 Hrs
REQUIREMENT - III
FREQUENCY OF READINGS FOR ACCURATE DATA COLLECTION
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SCOPE OF WORK (SPEC) FOR ENERGY AUDIT OF A TYPICAL THERMAL POWER PLANT UNITS
A. BOILER• Boiler efficiency by heat loss method as per ASME PTC-4-1
guidelines and give break up of losses
• Furnace air ingress at different levels upto I.D.Fans
• Air heater performance Gas side efficiency Air side and gas side pressure drop across APH Air leakage across APH X – ratio i.e heat capacity of air to gas capacity.
• Aux power consumption and combined efficiency of fan and motors
of ID, FD & PA fans.
• Aux power consumption of coal mills, feeders vs loading.
REQUIREMENT – 4
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B. TURBINE1. Turbine cycle heat rate as per ASME-PTC-6 methodology and
instrumentation
2. HP and IP cylinders efficiency
3. Turbine pressure survey4. TTD & DCA of HP / LP heaters Pressure drop across heaters
5. Condenser performance i.e
Condenser back pressure after duly considering the effect of
present C.W inlet temp, C.W flow, heat load on condenser
and air ingress to condenser vis-à-vis design conditions
C.W side pressure drop in condenser
6. Cycle losses
7. Performance of turbine glands
8. Ejector performance
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C. ELECTRICAL SYSTEM
1 Motors Assessment of Loading condition of HT and LT motors of Boiler area, Turbine area and Balance of Plant area.
Assessment of operating parameters like load variation, Power factor of HT and LT motors consuming power more than 50 KW.
2 Capacitors Assessment of health of capacitors.
3 Plant Lighting system Lighting load survey and Assessment of installed load efficacy (I.L.E) and I.L.E ratio at various areas of plant.
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D. Pump performance for BFPs, CEPs, Aux C.W.P & C.W.P and
pumps consuming power more than 50 KW etc.
• Check Performance of the pumps by comparing the corrected
measured flow at operating speed to design speed with that of
the expected flow derived from the characteristic curves against
the corrected total dynamic head at design speed.
• Determine Pump efficiency as the ratio of power input to the
pump shaft to hydraulic power.
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E Insulation Audit:A. Walk through survey of Boiler, Turbine and associated steam
piping to identify the damaged and Hot spot area.B. Surface temperature measurement at the damaged and Hot
spot area by infrared temperature indicator.C. Estimation of heat loss in the hot spots and damaged
insulation area. F Balance Of Plant(i) Compressed air system:• Free Air Delivery i.e. Capacity evaluation of the Plant and
Instrument air compressors.• Checking volumetric efficiency of compressors.• Assessment of compressed air leakage quantity.
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(ii) Air conditioning system:
• Performance evaluation of AC Plant w.r.t net cooling /
refrigeration capacity along with heat load of Air handling unit and
energy requirements.
(iii) Ash Plant
• Performance of ash Slurry pumps through power measurement
and flow measurement.
• Ash water ratio assessment and recommendations for
optimization in water and power consumption.
(iv) Cooling Tower Performance
It shall include establishment of
• Liquid/Gas ratio
• Cooling tower effectiveness, approach and range
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(V) Coal Handling Plant
Input Power measurement of all the key equipment of the CHP area
like: Paddle feeders, Conveyors, Stacker & Re-claimer, Wagon
Tipplers, Crushers,
NOTE:
• ENERGY CONSERVATION MEASURES TO BE SUGGESTED
IN ALL THE ABOVE AREAS OF AUDIT.
• ENERGY AUDIT PROCEDURE TO BE SUBMITTED ALONG
WITH AUDIT MEASUREMENT SCHEMES AND APPROVED
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1.0 USEFULNESS OF ENERGY AUDIT IN THERMAL POWER STATION • Identifies wastage areas of fuel, power and water utilization.• Reduction in cost of generation by implementing findings of EA.• Increases power generation by efficient utilization of steam in turbine
cycle and reduction in Aux Power Consumption.• Maintenance planning and availability improvement.• Provides guidance in loading sequences of the units. • Identification and rectification of errors in on-line instruments.• Leads to reduction in green house gases. • Utilizes specialized services of experienced engineers.• Training of O&M staff for efficient control of unit operation.• Improves competitiveness by reducing unit generation. • Creates bench mark for all equipments and systems.• Fulfills bureau of energy efficiency mandatory requirement of Energy
Audit.
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1) Operation of machine at very low turbine I/L parameters.
2) Operation of turbine at lower loads.
3) HP and IP turbine cylinder efficiencies are very low.
4) Main steam and HRH inlet temperature to turbine very low.
5) RH pressure drop high.
6) High quantity of SH Spray and its tapings before HPH-5 resulting in loss of heat because of changed cycle.
METHODS / OBSERVATIONS FOR SAVINGS ENERGY IN POWER PLANT
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7) HP heater no. 5 out of service.
8) Turbine cycle not operating as per design scheme i.e. Ejector and Deaerator pegging steam from PRDS header as against normal source from deaerator & extraction steam respectively.
9) Passing of turbine cycle drain valves.
10) Make up quantity to cycle is very high which indicates
excessive system steam (heat) loss.
11) TTD & DCA of heaters high.
METHODS / OBSERVATIONS FOR SAVINGS ENERGY IN POWER PLANT
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12) Condenser air ingress and dirty tubes.
13) Under loading of motors
14) Excessive air leakage in compressed air system
15) Faulty insulation
16) Drain valves passing
17) Air ingress to Boiler furnace
18) FAD of compressors low
METHODS / OBSERVATIONS FOR SAVINGS ENERGY IN POWER PLANT
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Thanks…Energo Engineering Projects Ltd.A-57/4, Okhla Industrial Area, Phase – II Phone: +91 - 11 - 26385323/ 28/ 29/ 38Fax: +91 – 11 – 26385333E-mail: [email protected] [email protected]: www.energoindia.com