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Welcome

Welcome. Combustion Optimization. Emerging Market Requirements. Higher Availability & Reliability Highest Plant efficiency Lower Heat Rate Minimum Auxiliary Power Consumption Ability to operate under adverse grid conditions/fluctuation in demand Minimum emission of Pollutants.

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Welcome

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  1. Welcome

  2. Combustion Optimization

  3. Emerging Market Requirements Higher Availability & Reliability Highest Plant efficiency Lower Heat Rate Minimum Auxiliary Power Consumption Ability to operate under adverse grid conditions/fluctuation in demand Minimum emission of Pollutants

  4. Measures to improve Plant Efficiency Boiler side: Minimum flue gas temperature at AH outlet Minimum excess air at AH outlet Minimum un-burnt Carbon loss Minimum RH spray Minimum SH spray Reduced Auxiliary Power Consumption

  5. Measures to improve Plant Efficiency … Turbine side measures Higher steam parameters ( MS Pressure & SHO/RHO Steam Temp). Adoption of double reheat cycle Increasing feed water temperature with Enhanced Regenerative feed heating Increase in condenser vacuum

  6. 2a. Boiler - Various Losses By Gas Dry Gas Loss Loss due to Moisture in Gas Due to Fuel Moisture Due to moisture formed by H2 in fuel Due to air moisture By Ash Unburnt carbon Loss Sensible heat loss in Fly ash Sensible heat loss in Bottom ash Other Loss Carbon monoxide Loss Radiation Loss Heat loss through Mill rejects

  7. Factors Influencing Various Losses

  8. Ensure consistent mill fineness - +50, - 200 Good burner maintenance Proper secondary air adjustment - SADC Reduce PA air to the minimum possible – min PA velocity variation Cut out oil support at higher loads where coal flame is stable as oil preferentially deplete o2 in the area and reduces ‘o2 ‘ for coal particles to burn Check coal property and tune combustion Keep boiler heat transfer surface clean so that losses can be reduced thus reducing the coal input Methods to reduce unburnt carbon loss

  9. Methods to reduce dry gas loss Correct excess air High mill outlet temp. Better combustion – combustion tuning Arrest air ingress Air heater performance – leakage , proper elements Cleanliness of the heat transfer surfaces

  10. The Major parameters to be looked into for Better Efficiency: • FG Temp • Excess air Level • Mill reject rate and • Unburnt carbon in ash • Control / Optimization of other parameters (i.e GCV, H2, Fuel moisture and Air Moisture) are not possible.

  11. Major reasons for increase in APC Operation of unit with higher excess air Air heater leakage Higher PA fan outlet pressure High mill fineness, more no. of mills Air ingress into boiler Pluggage in line / ducting Partialy blocked APH

  12. Sources of air ingress Furnace roof Expansion joints Air heaters Ducts Esp hoppers Peep holes Manholes Furnace bottom

  13. FACTORS AFFECTING AUXILIARY POWER ID FANS AH LEAK GAS TEMPERATURE DUCT LEAKAGES EXCESS AIR LOAD/ PLANT HEAT RATE DRAUGHT LOSS AH CHOKING FD FANS AH LEAK WIND BOX PR. EXCESS AIR LOAD/ PLANT HEAT RATE PRESSURE LOSS AH CHOKING SCAPH CHOKING PA FANS AH LEAKAGE PA HEADER PR. MILL AIR FLOW PRESSURE LOSS AH CHOKING MILL COAL QTY. GCV LOAD/ PLANT HEAT RATE COAL MOISTURE HGI COAL FINENESS MILL CONDITION Factors affecting APC - a summary

  14. Capacity Reduction in a Boiler Fuel input Low cv coal Milling capacity Grinding capacity Drying capacity Carrying capacity Drive capacity Draught system ID fan limitations Pressure drops high AH choking Chimney back pressure high High volume AH leakages Duct leakages High gas temperatures Worn out impellers Metal temperatures high High spray requirements Fouling of surfaces

  15. CASE STUDIES

  16. Case Study-1 • Problem: • Heavy clinkering build up upto S-panel /Bottom of burner reported from many boilers • Investigations: • Poor mill fineness (50% through 200 mesh) • Non-working of SADC as per control • Poor coal quality – usage of ground stock • Non- working of wall blowers • Improper evacuation of bottom ash • Solution:After taking above corrective actions no further problems faced.

  17. Case Study-2 • Problem: Frequent choking of coal pipe • Investigations: Clean air flow test • Checking of orifice • Calibration of coal flow/air flow -check • Foreign material entrapped in classifier ( cloth) • Solution: Problem resolved after removal of foreign material from classifier.

  18. THANK YOU

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