FOCUS AREAS           FORECONOMIC DG SET OPERATION        D. PAWAN KUMAR
TYPICAL GRID POWER SCENARIO FEATURES   Frequent power trippings   Power cuts   Low voltage problems   Low frequency pr...
ADVANTAGES In the context of utility sector short falls, it augurs well in the   national perspective to encourage captiv...
TYPES OF CAPTIVE POWER OPTIONS AVAILABLE Purely power generation mode or: • Coal/oil based thermal cogen (boiler-turbine-...
TYPES OF CAPTIVE POWER OPTIONS AVAILABLE   Gas based / oil based GT route   Combined cycle    • Open cycle (GT only)    ...
DG OPTION FROM THE COMMON USER STAND      POINT – ATTRACTIVE FEATURES    Low project payback period 2-3 years    Low spa...
AMONGST CAPTIVE GENERATION OPTIONS     Diesel generation attributes are:      •     Efficiency 43 – 45%      •     Very c...
DG OPTION FROM COMMON USERS STAND        POINT – ATTRACTIVE FEATURES    Low project implementation period (Less than 1yea...
DG SYSTEM OPTIONS INCLUDE:Individual user end installationsCo-operative ventures/centralized generationfor economy of scal...
IMPACT OF INDUSTRIAL DIESEL POWER GENERATION       Effect on foreign exchange reserves, energy security     • Oil import b...
IMPACT OF INDUSTRIAL DIESEL POWER GENERATION  A good share of DG Set population is old/second hand  with low efficiencies ...
IMPACT OF INDUSTRIAL DG POWER GENERATION Regular energy audit and performance monitoring would   help to identify appropr...
EXPERIENCES INDICATE 5 to 10%FUEL SAVINGS POTENTIAL THROUGH   INCORPORATION OF VARIOUS           MEASURES
LOADING IMPROVEMENTS Under loading is the root cause for fuel guzzling in DG Sets KW readings efficacy often suspectEng...
LOADING IMPROVEMENTS Parallel operation among DG Sets & with grid can help Short run operations increase specific fuel c...
ECONOMIC OPERATION OF DG SETS:              – AREAS OF CONCERN Maintenance practices   • Inadequacy and absence of record...
DG Set RefkW kW                    DG Set Capacity                    Derated DG Set Capacity                    Fuel Used...
MAINTENANCE COST RECORDS Break-up of cost also help in budgeting, maintenance planning An illustrative DG set Maintenanc...
DG Set Reference : ABC                                         % Total MaintenanceS.No.      Failure Type                 ...
CONDITION MONITORING RECORDS While OEM Guidelines are often conservative, condition    monitoring is a powerful technique...
VIBRATION ANALYSIS Desirable for bearings, Gears, Turbochargers, Pumps Illustrative observations on DG Sets in a plant  ...
DESIRABLE ON-LINE PARAMETERS TO TRACK: Suction air temperature Charge air pressure Charge air temperature (before and a...
TYPICAL FAULTS TO LOOK OUT FOR: Based on OEM Guidelines & as run observations, diagnosis of   faults is called for:    T...
WASTE HEAT RECOVERY IN DG SETS Close to 35% of energy exhausted through stack Exhaust temperature 350OC to 500OC Scope ...
WASTE HEAT RECOVERY (WHR) IN DG SETS Factors affecting WHR      Set loading, temperature of gases      Hours of continu...
EXHAUST GAS TEMPERATURE & FLOW vs %                         LOADING 5 MW set with turbo charging – an illustration:      ...
EXHAUST GAS TEMPERATURE & FLOW vs.                % LOADING Economics vary w.r.t. set loading and base load operation.   ...
EMERGING AREAS OF INTEREST Suction air cooling schemes for increasing capacity Fuel additives / treatment systems for be...
   Ensure steady load conditions on the DG set, and provide    cold, dust free air at intake   Improve air filtration. ...
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Focus areas in economic operation of DG sets

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Focus areas in economic operation of DG sets

  1. 1. FOCUS AREAS FORECONOMIC DG SET OPERATION D. PAWAN KUMAR
  2. 2. TYPICAL GRID POWER SCENARIO FEATURES Frequent power trippings Power cuts Low voltage problems Low frequency problems Captive power generation has become a necessity
  3. 3. ADVANTAGES In the context of utility sector short falls, it augurs well in the national perspective to encourage captive generation. Offsets large capital investment for utility side Capacity addition T & D loss component literally vanishes Power quality ensured (V, f)
  4. 4. TYPES OF CAPTIVE POWER OPTIONS AVAILABLE Purely power generation mode or: • Coal/oil based thermal cogen (boiler-turbine-generators) Fully condensingcondensing Extraction Back pressure
  5. 5. TYPES OF CAPTIVE POWER OPTIONS AVAILABLE Gas based / oil based GT route Combined cycle • Open cycle (GT only) • Closed cycle • GT, HRSG, ST DG Sets • Diesel based • Heavy fuel oil based
  6. 6. DG OPTION FROM THE COMMON USER STAND POINT – ATTRACTIVE FEATURES  Low project payback period 2-3 years  Low space requirements (Even a shed will do) Good conversion efficiency Easy fuel to handle Quality of Power ensured (V, f)
  7. 7. AMONGST CAPTIVE GENERATION OPTIONS Diesel generation attributes are: • Efficiency 43 – 45% • Very compact • Investments lower • Gestation period lowest (1 – 1.75 years) • Low auxiliary power needs
  8. 8. DG OPTION FROM COMMON USERS STAND POINT – ATTRACTIVE FEATURES Low project implementation period (Less than 1year) Low space requirements Good conversion efficiency Easy fuel to handle Quality of power ensured (V, f) Investments lower than utility generation Waste Heat Recovery possible to reduce operational expenses
  9. 9. DG SYSTEM OPTIONS INCLUDE:Individual user end installationsCo-operative ventures/centralized generationfor economy of scaleGroup of industries generate by funds pooledCompanies promoted to set up and tooperate power stationsPower generated is distributed to participatingindustries through utility distribution system(wheeling route)
  10. 10. IMPACT OF INDUSTRIAL DIESEL POWER GENERATION Effect on foreign exchange reserves, energy security • Oil import bill constitutes good part of export earnings in many developing countries • Real cost of oil is much different from the administered cost • Highest operational efficiency of diesel power generation makes economic sense for industry & has a much larger impact in national economy
  11. 11. IMPACT OF INDUSTRIAL DIESEL POWER GENERATION A good share of DG Set population is old/second hand with low efficiencies & high SFC on account of factors like • Ageing • Inadequacies in maintenance • Low capacity utilisation • Fluctuating load characteristics • Inefficient operational practices • Derating effects • Wrong sizing and selection issues
  12. 12. IMPACT OF INDUSTRIAL DG POWER GENERATION Regular energy audit and performance monitoring would help to identify appropriate rectification measures retrofits & judicious replacement policies Compared to stand alone operation, parallel operations help to raise the operational economy of DG Sets on account of higher loading, with the options including: • Parallel operation of captive DG sets • Paralleling captive DG sets with grid
  13. 13. EXPERIENCES INDICATE 5 to 10%FUEL SAVINGS POTENTIAL THROUGH INCORPORATION OF VARIOUS MEASURES
  14. 14. LOADING IMPROVEMENTS Under loading is the root cause for fuel guzzling in DG Sets KW readings efficacy often suspectEngine capability (BHP based) limits to be referred to, to assess mechanical loadingAlternator capability (kVA based) limits to be referred to, to assess electrical loadingCheck of exhaust temp, fuel rack setting,charge air pressure, turbocharger rpm helpful to assess engine loadingkWh, PF, monitoring helpful, to assess electrical loading Use of trivector type static energy meters desirable on DG Sets
  15. 15. LOADING IMPROVEMENTS Parallel operation among DG Sets & with grid can help Short run operations increase specific fuel consumptionChoice of loads on DG Sets & choice of DG Sets is also a key for improvement
  16. 16. ECONOMIC OPERATION OF DG SETS: – AREAS OF CONCERN Maintenance practices • Inadequacy and absence of records on maintenance. & operation Operation records inadequacy Inadequacies and absence of • Instrumentation • Monitoring A MIS template of desirable information follows:
  17. 17. DG Set RefkW kW DG Set Capacity Derated DG Set Capacity Fuel Used % Avg. % Loading w.r.t. Derated CapacityLits/kWh Lits/kWh Specific Fuel Oil Consumption Specific Lube Oil Consumption O C Charge Air In / Out Temperature O C Exhaust Gas Temperature Kg/cm2 rpm Turbocharger Pressure Turbocharger rpm
  18. 18. MAINTENANCE COST RECORDS Break-up of cost also help in budgeting, maintenance planning An illustrative DG set Maintenance cost break-up follows:
  19. 19. DG Set Reference : ABC % Total MaintenanceS.No. Failure Type Cost 1. Fuel Injection & Supply 9.7 2. V/V, V/V System & Seats 3.6 3. Cooling System & Water Leakage 0.4 4. Controls & Electricals 0.0 5. Governers 0.0 6. Pistons 43 7. Lubrication System 6.2 8. Bearings 17.9 9. Turbocharger 1.3 10. Gears & Drives 0.0 11. Miscellaneous 7.2 100
  20. 20. CONDITION MONITORING RECORDS While OEM Guidelines are often conservative, condition monitoring is a powerful technique for cost control • Typical examples Lub Oil Tests • Color / visual observations • Kin. Viscosity at 40OC/100OC • Viscosity index • Flash point (OC) • Total base number • Cracking test
  21. 21. VIBRATION ANALYSIS Desirable for bearings, Gears, Turbochargers, Pumps Illustrative observations on DG Sets in a plant Displacement Velocity Location Orientation Range (µ) Range (µ) Turbo Horizontal 60 – 130 8 – 13 Charger Vertical 68 – 140 4 – 8.4 Suction Axial 90 – 180 7.2 – 16 Turbo Horizontal 80 – 130 8 – 8.4 Charger Vertical 58 – 150 4.6 – 14 Discharge Axial 100 – 190 7.8 – 16 Alternator Horizontal 18 – 40 2–4 Bearing Vertical 25 – 50 2.8 – 6.4 Axial 28 – 60 3.2 – 14 Such observations can help improve preventive maintenance function and availability of DG Sets
  22. 22. DESIRABLE ON-LINE PARAMETERS TO TRACK: Suction air temperature Charge air pressure Charge air temperature (before and after Cooler) Turbocharger (T.C) RPM Gas Temperature at cylinder exhaust Gas temperature, at T.C. In and Out Fuel rack / rocker arm setting Alternator V, A, PF, kW, & Hz. Fuel flow indicator Ambient air DBT / WBT indicator Conductivity meter for CW system
  23. 23. TYPICAL FAULTS TO LOOK OUT FOR: Based on OEM Guidelines & as run observations, diagnosis of faults is called for:  Typical concern areas include: • Choked fuel valves • Leaky piston rings • Leaky exhaust valves • After burning • Early firing Record of overhauls  Historical data before / after each overhaul helps to • Check efficacy of overhaul carried out • Establishing in-situ parameter limits
  24. 24. WASTE HEAT RECOVERY IN DG SETS Close to 35% of energy exhausted through stack Exhaust temperature 350OC to 500OC Scope for waste heat recovery Indicative recovery potential in kCal per hour would be:  m x 0.25 x (tg – 180) where m, is gas quantity in Kg / Hr ( typically 8 Kg / kWh ) and tg is exhaust gas temperature,180 being the safe exit gas temperature limit, after, heat recovery.
  25. 25. WASTE HEAT RECOVERY (WHR) IN DG SETS Factors affecting WHR  Set loading, temperature of gases  Hours of continuous operation  Back pressure of set  End use options available for Steam / waste heat Refrigeration capacity feasible through vapor absorption system option:  About 100 TR per MW output, based on 500KG waste heat steam /MW and 5KG/TR steam required for a double effect VAR system. Water Lithium Bromide VAR schemes for 8OC chilled water available
  26. 26. EXHAUST GAS TEMPERATURE & FLOW vs % LOADING 5 MW set with turbo charging – an illustration: Gas Flow Temperature Load % Kg/Sec O C 60 7.5 325 70 9.08 330 90 10.08 355 100 11.84 370 At 60% load, WHR scope is 0.95 x 106 kCal / Hr At 90% load, WHR scope is 1.42 x 106 kCal / Hr
  27. 27. EXHAUST GAS TEMPERATURE & FLOW vs. % LOADING Economics vary w.r.t. set loading and base load operation. Back pressure limit of 250 – 300 mmWC, sets limit on limiting pressure drop in Waste Heat Recovery system.  Large convective Heat Transfer Area called for  Typically, 0.5 TPH Waste Heat based steam generation scope exists per MW output.
  28. 28. EMERGING AREAS OF INTEREST Suction air cooling schemes for increasing capacity Fuel additives / treatment systems for better efficiency High efficiency turbochargers Improved Noise control systems Harmonics filtration Tri-generation adoption
  29. 29.  Ensure steady load conditions on the DG set, and provide cold, dust free air at intake Improve air filtration. Ensure fuel oil storage, handling and preparation as per manufacturers’ guidelines/oil company data. Calibrate fuel injection pumps frequently. Ensure compliance with OEM maintenance checklist. Ensure steady load conditions, avoiding fluctuations, imbalance in phases, harmonic loads. For base load operation, consider waste heat recovery system steam generation and vapour absorption system adoption where viable. Consider parallel operation among the DG sets for improved loading . Provide adequate instrumentation for monitoring performance, and plan for operations and maintenance accordingly.
  30. 30. THANK YOU

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