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PRESENTATION ON ESSENTIAL REQUIREMENTS FOR ENERGY AUDITS IN THERMAL POWER STATIONS BY H.S.Bedi Sr. Vice President (Power) Energo Engineering Projects Ltd. A-57/4, Okhla Industrial Area, Phase – II, New Delhi - 110020. “You cannot Manage what you cannot Measure” (Accurately)
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PRESENTATION ON ESSENTIAL REQUIREMENTS FOR ENERGY AUDITSIN THERMAL POWER STATIONSBY H.S.BediSr. Vice President (Power)Energo Engineering Projects Ltd.A-57/4, Okhla Industrial Area,Phase – II, New Delhi - 110020
“You cannot Manage what you cannot Measure” (Accurately) - Jack Welch, CEO, General Electric
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
1.2 EFFECT OF INSTRUMENTATION ON ACCURACY • Plant on-line instruments with few audit instruments Accuracy around 3.0%. • 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 THAN • ASME-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%
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.
EFFECT OF INSTRUMENT INACCURACY ON HP/IP Turbine Efficiency
REQUIRED ACCURACY AND CALIBRATION OF THE INSTRUMENTS • The proposed instruments should have following level of accuracy. • Thermocouples and PRTs – ASME special class ‘A’ i.e ½ DIN tolerance • Pressure and differential pressure - 0.1% • transmitters better than • Power Meter for generator & - 0.1% • Unit Aux Power measurement • iv 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.
FG Expansion Bellow Economizer HVS APH Sampling Locations APH FG REQUIREMENT – II PROPER SCHEMES FOR ENERGY AUDIT
Annexure - I BOILER EFFICIENCY AND APH TEST SCHEME & INSTRUMENTATION DIAGRAM Grid measurement for gas compositionand gas temp. at air pre heater inlet / outlet. DEPTH
REQUIREMENT - III FREQUENCY OF READINGS FOR ACCURATE DATA COLLECTION TURBINE CYCLE AUDIT Pressure - 5 Minutes Temperature - 5 Minutes Flow - 1 Minute Power - 1 Minute Levels - 10 Minutes BOILER UNIT AUDIT Temperature - 15 to 30 Minutes Flue Gas Composition - ½ to one hour DURATION OF AUDIT TEST Turbine Cycle - 2 Hrs Boiler Unit - 4 Hrs
SCOPE OF WORK (SPEC) FOR ENERGY AUDIT OF A TYPICAL THERMAL POWER PLANT UNITS REQUIREMENT – 4 • 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.
B. TURBINE • Turbine cycle heat rate as per ASME-PTC-6 methodology and instrumentation • HP and IP cylinders efficiency • Turbine pressure survey • TTD & DCA of HP / LP heaters Pressure drop across heaters • 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 • Cycle losses • Performance of turbine glands • Ejector performance
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.
E Insulation Audit: • Walk through survey of Boiler, Turbine and associated steam piping to identify the damaged and Hot spot area. • Surface temperature measurement at the damaged and Hot spot area by infrared temperature indicator. • 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.
(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
(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
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.
METHODS / OBSERVATIONS FOR SAVINGS ENERGY IN POWER PLANT • Operation of machine at very low turbine I/L parameters. • Operation of turbine at lower loads. • HP and IP turbine cylinder efficiencies are very low. • Main steam and HRH inlet temperature to turbine very low. • RH pressure drop high. • 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 • HP heater no. 5 out of service. • 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. • Passing of turbine cycle drain valves. • Make up quantity to cycle is very high which indicates excessive system steam (heat) loss. • TTD & DCA of heaters high.
METHODS / OBSERVATIONS FOR SAVINGS ENERGY IN POWER PLANT • Condenser air ingress and dirty tubes. • Under loading of motors • Excessive air leakage in compressed air system • Faulty insulation • Drain valves passing • Air ingress to Boiler furnace • FAD of compressors low
Thanks… Energo Engineering Projects Ltd. A-57/4, Okhla Industrial Area, Phase – II Phone: +91 - 11 - 26385323/ 28/ 29/ 38 Fax: +91 – 11 – 26385333 E-mail: energo@del3.vsnl.net.in energo@energo.co.in Web: www.energoindia.com