How to reduce Boiler Auxiliary Power consumption??
Boilers are the heart of power plants and industrial utilities, but their efficiency is not just measured by steam generation and fuel consumption. But also, Boiler performance is assessed by its power consumption to generate the steam.
Generally Auxiliary Power consumption in Boiler plant is electrical power consumed by the auxiliaries of that Boiler to generate the steam.
What is Auxiliary Power Consumption (APC) in Boilers?
Auxiliary power refers to the portion of generated power that is consumed internally by the plant for running essential equipment such as:
- ID, FD, and PA Fans
- Boiler feed pumps
- Cooling water and ash handling systems
- Fuel handling and milling systems
- Fuel feeding system
- Air compressors
- Lighting and instrumentation
Typically, auxiliary power consumption in thermal power plants ranges from 6% to 10% of gross power generation. Reducing even 1% can result in huge energy savings annually.
What is the significance of reducing Boiler auxiliary power consumption (APC)??
Reducing Boiler Auxiliary Power Consumption is highly significant for both economic and operational reasons in power plants, process industries, and captive boiler units
Auxiliary power consumption—the electricity used by pumps, fans, drives, lighting, and other support systems—plays a significant role in overall plant performance and cost-effectiveness. Reducing this auxiliary consumption improves plant efficiency, lowers operating costs, and minimizes environmental impact.
Benefits of reduction of Auxiliary Power consumption (APC)?
- Lower Operating Cost
- Improved Plant Profitability
- Higher Net Plant Efficiency (Heat Rate Improvement)
- Better Equipment Life
- Reduced Fuel Consumption
- Improved System Reliability
- Flexibility in Low Load Operations
Reducing boiler auxiliary power consumptionsaves cost, boosts efficiency, reduces emissions, improves equipment reliability, and enhances overall competitiveness of the plant.
How to reduce the Boiler Auxiliary Power consumption (APC)?
In a Boiler plant around 95% of the Auxiliary Power consumption (APC) is from Boiler feed pumps and fans and remaining 5% is from fuel feeding, fuel handling system and air compressors.
In any Boilers around 45-50% of the major Auxiliary Power consumption (APC) is by Boiler feed pumps and remaining 45-50% is from fans.
So, it is utmost important to reduce Auxiliary Power consumption (APC) Of Boiler fans and pumps.
Following are the plan of actions to reduce Auxiliary Power consumption (APC) of the Boiler pl
- Incorporate VFDs to all Boiler feed pumps
- Operate the pumps in auto logic where pump speed should vary as per Boiler drum pressure: In Auto logic Boiler feed pumps speed varies based on its head pressure and header pressure is the difference between drum pressure and pressure loss in control valves and economiser.
- Ensure feed water control valve is operating above 50%, to reduce the pressure drop.
- Carryout regular preventive maintenance of the Boiler feed pumps
- Ensure correct DP in suction strainers
- Ensure enough Deaerator level
- Ensure Boiler feed pumps auto recirculation valves are leak free.
- Optimize the pumps capacity, ensure pump will operate above 80% of their maximum capacity.
- Never run the Boiler feed pumps with throttle valve opened
- Incorporate VFDs to all the fans
- Operate the Boiler in Auto combustion
- Optimize the moisture content in the fuel, as high moisture fuel calls for more excess air and hence more load on FD and ID fans. Properly sized coal, low-moisture biomass, or high-grade oil/gas improves efficiency.
- Use oxygen analysers and advanced combustion control to avoid excess
- Keep air preheater, ducting, and filters clean to reduce fan power.
- Minimize leakages in ducting and expansion joints to reduce fan loading.
- Replace old fans with aerodynamically designed blades and IE3/IE4 motors.
- Use energy efficiency pumps for DM water make up
- Carryout regular preventive maintenance of pumps
- Ensure suction strainers are always clean.
- Ensure recirculation lines are minimized or auto-controlled for all the pumps.
- Arrest any steam and water leakages in the Boiler plant
- Optimise air pressure and quantity required for ash handling
- Operate the ash handling system based on ash collection or quantity in individual zones
- Operate the ash handling plant on probe mode
- Reduce the discharge pressure of air compressors wherever possible
- Minimise ash conveying distance wherever possible
- Recover heat from compressor for heating DM water
- Incorporate VFDs to all fuel feeding system
- Ensure right quality fuel is being used to reduce unburnt and excess air
- Use skilled operators in Boiler operation
- Avoid manual operation
- Replace all old and over rated motors with energy efficient motors
- Avoid compressed for cleaning applications
- Clean suction air filters of compressors regularly as 250 mmwc pressure drop in suction filter will lead to the reduction of compressor efficiency by 2%.
- Locate compressors at lower level as at higher elevation compressors consume more power.
- Provide optimum height silencers for high speed centrifugal fans and take care the silencer is free from all obstacles.
- Check all equipment vibrations and alignment to avoid unnecessary power consumption and machine failure.
- Use Mechanical seal over conventional gland packings
- Incorporate timers of street and plant lighting system.
- Replace all the plant lighting bulbs by highly efficient LED or any other energy efficient bulbs.
- Carryout regular cleaning of Air heaters and other heat exchangers
- Maintain Proper Water Chemistry: Prevent scaling & corrosion that reduce efficiency.
- Prevent jamming and overloading through predictive maintenance.
- Shut down non-essential auxiliaries during low load operation
- Keep steam, air, and water leakages under control.
By practicing above suggested tips, Boiler Auxiliary Power consumption (APC) can be reduced
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