Guess what: A beginner’s guide to the air preheater in power plants or the flue gas heat exchanger used in flue gas desulfurization, also known as GGH

Thread Content

The answers were revealed too quickly. This is a rotor-type air preheater; as the name suggests, it involves a rotor along with heat storage plates on that rotor, which rotate to absorb heat from the hot flue gas and then transfer it to the cooler air side to heat the air. The rotation speed is roughly 10 rpm, resulting in a very high heat exchange efficiency. The main problems include air leakage, stress-induced deformation, and low-temperature corrosion. There is also a type of rotary air preheater with shrouds: in this design, the rotor does not move, while the shrouds on either side of the rotor (one containing flue gas and the other air) rotate back and forth. Compared to rotary preheaters with rotating rotors, this type suffers from severe air leakage, and its components are difficult to replace; moreover, the issues of low-temperature corrosion and stress-induced deformation remain unaddressed. Currently, many coal-fired power plants use the former, accounting for at least 80% or more of the total. If you delve deep into it, you could write a doctoral thesis