BOILERS

• Preheat combustion air with waste heat.
• (22 °C reduction in flue gas temperature increases boiler efficiency by 1%)
• Use variable speed drives on large boiler combustion air fans with variable flows.
• Burn wastes if permitted.
• Insulate exposed heated oil tanks.
• Clean burners, nozzles, strainers, etc.
• Inspect oil heaters for proper oil temperature.
• Close burner air and/or stack dampers when the burner is off to minimize heat loss up
• the stack.
• Improve oxygen trim control (e.g. — limit excess air to less than 10% on clean fuels).
• (5% reduction in excess air increases boiler efficiency by 1% or: 1% reduction of
• residual oxygen in stack gas increases boiler efficiency by 1%)
• Automate/optimize boiler blowdown. Recover boiler blowdown heat.
• Use boiler blowdown to help warm the back-up boiler.
• Optimize deaerator venting.
• Inspect door gaskets.
• Inspect for scale and sediment on the water side.
• (A 1 mm thick scale (deposit) on the water side could increase fuel consumption by 5 to 8%.)
• Inspect for soot, flyash, and slag on the fire side. 
• (A 3 mm thick soot deposition on the heat transfer surface can cause an increase in fuel consumption to the tune of 2.5%)
• Optimize boiler water treatment.
• Add an economizer to preheat boiler feedwater using exhaust heat.
• Recycle steam condensate.
• Study part-load characteristics and cycling costs to determine the most-efficient mode for operating multiple boilers.
• Consider multiple or modular boiler units instead of one or two large boilers.
• Establish a boiler efficiency-maintenance program. Start with an energy audit and follow-up, then make a boiler efficiency-maintenance program a part of your continuous energy management program