How many types of air preheaters and Explain its advantages? An air preheater (APH) is a General term to describe any device, the air before another process is heated (e.g., combustion in a boiler) with the main objective to improve the thermal efficiency of the process.
Air pre-heating can increase boiler efficiency and reduce chimney loss. They can be used alone or replace a heat recovery system or replace the Steam coil. An air preheater (APH) is a device used in steam boilers to transfer heat from the flue gases to the combustion air before it enters the oven. Air preheater recovers the heat from the boiler flue gas and increases the thermal efficiency of the boiler . The flue gases are fed into the combustion gas stack at a lower temperature to control the temperature of the gases.
The combustion air preheaters are used in large boilers in thermal power plants to generate electricity from such fossil fuels, biomass or waste.
The purpose of the air preheater heat recovered from boiler flue gases that increase the boiler thermal efficiency by reducing the useful heat lost in flue gases. As a result, the flue gas is also sent to the stack flue gas(or chimney) at lower temperatures, making simplified construction of duct and exhaust stack. It also allows control over the temperature of the gas leaving the stack (to meet emissions regulations, for example,)