Flue Gas Heater

A flue gas heater, also known as a flue gas economizer or waste heat recovery unit, is a device used to recover heat from the flue gas generated by combustion processes. It is commonly employed in industrial facilities, power plants, and other systems that produce significant amounts of flue gas.

The basic principle of a flue gas heater involves the exchange of heat between the hot flue gas and a heat transfer medium, such as water or thermal oil. The recovered heat can then be utilized for various purposes, such as preheating combustion air, heating water, or generating steam.

Here's how a typical flue gas heater works:

Flue Gas Inlet: The hot flue gas, which contains waste heat, enters the flue gas heater through an inlet.

Heat Transfer Surface: Inside the flue gas heater, there are heat transfer surfaces, typically in the form of tubes or plates. These surfaces come into direct contact with the flue gas, allowing the transfer of heat from the flue gas to the heat transfer medium.

Heat Exchange: The heat transfer medium, such as water or thermal oil, flows through the heat transfer surfaces. As it passes in close proximity to the hot flue gas, heat is transferred from the flue gas to the medium through conduction and convection.

Heat Recovery: The heat transfer medium absorbs the heat from the flue gas, thereby cooling the flue gas and increasing the temperature of the medium. The cooled flue gas then exits the flue gas heater.

Utilization of Recovered Heat: The heated transfer medium, now carrying the recovered heat, can be directed to a heat exchanger or used directly for specific applications. For example, it can be used to preheat combustion air before it enters the furnace or boiler, or it can be used to heat water or generate steam for various industrial processes.

The use of a flue gas heater allows for the recovery of waste heat that would otherwise be lost into the atmosphere, resulting in increased energy efficiency and reduced fuel consumption. It contributes to cost savings, environmental benefits, and improved overall thermal efficiency of the system or plant.