Energy Efficiency: Best Practices Thermal Power Stations

Transcription

1 Energy Efficiency: Best Practices Thermal Power Stations By Ravindra Datar Senergy Consultants (P) Ltd Cell:

2 Key Parameters Inlet (as well as Re-heater) Steam Pressure, Temperature Exhaust Steam Pressure, Temperature, Wetness Feed Water Pump Efficiency, Throttling, recirculation Fans (PA, SA & ID) Efficiency, Throttling Cooling Water System / Air Cooled Condensers Ash / Coal Handling System Boiler - Flue Gas (O 2, CO & Temperature) & air ingress Feed-water / Condensate Preheating System Ash quality Combustibles / Unburnt Carbon Auxiliary Steam Ejector, Gland Sealing / Leakages

3 Inlet Steam Higher Pressure may increase power generation, but could lead to lower boiler efficiency Lower Pressure can deteriorate performance & reduce power generation Higher Temperature may increase power generation, but could lead to lower boiler efficiency Lower Temperature can deteriorate performance & reduce power generation

4 Inlet Steam Pressure

5 Inlet Steam Temperature

6 Reheated Steam Higher temperature of reheated steam may increase power generation, but could lead to lower boiler efficiency Lower temperature of reheated steam may deteriorate performance & reduce power generation Higher pressure drop across the re-heater may deteriorate performance & reduce power generation

7 Reheated Steam Parameters

8 Exhaust Steam Higher Vacuum can increase power generation (up to certain point), but could lead to higher power for cooling water system Lower Vacuum can deteriorate performance & reduce power generation Monitor ingress of air into the system by periodically measuring vent air (with the help of bypass rotameter on the exhaust of ejector steam condenser).

9 Exhaust Steam Pressure (Vacuum)

10 VFD for BFP, PA, SA & ID Fans Eliminates / Minimizes throttling Through Control Valves for BFP IGV / dampers for PA, SA & ID Fans Operating Efficiency The Static Head constitutes a major part of the load for BFP & PA Fans; consequently operating efficiency is likely to vary at different speeds. The frictional head constitutes major part of the load for SA & ID fans; consequently operating efficiency is likely to be similar at different speeds. It is therefore essential to monitor operating efficiency of BFP & PA Fans and optimize the same at normal operating load

11 VFD for BFP / PA Fans

12 VFD for SA / ID Fans

13 Cooling Water System Optimization of overall system & net heat rate. Not to consider performance of cooling tower fans and / or pumps in isolation. VFD for CT Fans - consider Control based on Approach / basin temperature common for all the fans Pump Pressure & Pressure drops across Condenser, strainers, throttled valves (including return line at CT top) VFD for Pumps can be considered for varying load / low load applications.

14 Air Cooled Condensers Optimization of overall system & net heat rate. Not to consider power consumption of ACC fans in isolation. VFD for Fans - consider Control based on optimal vacuum common for all the fans Pressure drop in the exhaust duct need to be monitored and optimized.

15 Ash / Coal Handling System Consider dense phase conveying of dry ash Optimize the conveying cycle (Duration & Frequency) based on the actual quantity of ash and operating load on the boiler. Consider automation of the system. Consider heat recovery system for bed ash cooling Optimize pressure of compressed air used for conveying. Consider segregation of undersized before feeding to crushers

16 Boiler - Flue Gas Excess Air & Oxygen / Carbon monoxide Contents Flue gas Temperature profiling and at the APH outlet Air ingress & False air Effectiveness of various heat recovery systems like APH, Economizer.

17 Feed-water Preheating System Effectiveness of individual heat exchanges Extraction steam Pressure, Temperature as compared to design & isentropic values

18 Miscellaneous Combustibles in ash Blow down Control & heat recovery Auxiliary cooling water system Air conditioning system Lighting Water treatment system Steam for ejector (Extraction steam / vacuum pump) Steam flow through Gland Sealing / Leakages Insulation

19 Thank You!