Selasa, 21 Juni 2011

What is an Air Preheater?

air preheater
An air preheater (APH) is a general term to describe any device designed to heat air before another process (eg, combustion in the boiler) with the main objective improving the thermal efficiency of the process. Air Pre Heaters can increase boiler efficiency and decrease chimney loss. They can be used alone or to replace a heat recovery system or to 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 furnace. Air Preheater recovers the heat from the boiler flue gas and increases the thermal efficiency of the boiler . The Flue gases are sent to the fuel gas stack at a lower temperature It allows control over the temperature of gases.

The combustion air preheaters are used in large boilers are found in thermal power plants generate electricity from such fossil fuels, biomass or waste.

The purpose of the air preheater to recover heat 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, allowing simplified design of ducting and exhaust stacks. It also allows control over the temperature of the gas leaves the stack (to meet emissions regulations, for example).
air preheater schematic diagram
tubular type