AIR PRE HEATER

Air Preheater

• Air preheater is an heat recovery device, used in the last stage in the boiler
• It is a heat exchanger that absorbs heat from exit flue gas in boiler and transfers the heat to the incoming cold air (primary air & secondary air)
• In utility boilers it is used to heat the air required for combustion purpose (secondary air) as well as dry & transport (primary air) coal.

Air pre heater functions

• The efficiency of boiler increased by 1 % for every 20°C drop in flue  gas temperature.
• An air pre-heater heats the combustion air where it is economically feasible.

The pre-heating helps the following:

• Improving combustion.
• Drying the pulverized coal in pulverizers.
• Reducing the stack gas temperature and increasing the boiler efficiency.
• Enables efficient burning of lower grade fuels.
• Saves as much as 15% on fuel costs.