The design of these equipments allows heating the air from combustion gases of furnaces or engines when near the acid dewpoint temperature, with a corrosion risk for condensation (flue gas outlet temperature between 250 and 130 °C).
Depending on temperature and flue gas quality, it is necessary to use either cast iron pipes or glass tubes to avoid reaching the acid dewpoint. Sealing design depends on air pressure and flue gas composition.
The air preheaters reduce the fuel consumption in the Heat Recovery Steam Generators and Fired Heaters from 10% to 25% using heat recovery from flue gases and may be used with all types of fuel, such as coal, gas, biomass (wood) and diesel.
Air preheater allows energy efficiency of the fired heaters to be improved up to 92% and it is mainly designed for use in fired heaters, waste heat recovery boilers and incinerators.