Abstract
Fluidized bed gasifier can handle fuel more easily and operate at low temperature. However, a lot of tar is generated. This new gasifier, which is called a fludized bed gasifier with triple-beds and dual circulation, was proposed. Main features are the adoption of a triple-beds structure, the separation of circulation paths for tar-absorbing particle and fuel. Pyrolyzer and gasifier each have a two-stage fluidized bed. In the pyrolyzer, tar is formed together with gas produced during pyrolysis of the fuel in the lower stage, and the tar is absorbed by the tar-absorbing particle in the upper stage, that is, tar can be treated in the gasifier. The inhibition of char gasification can be reduced because the pyrolyzer and the steam gasifier are separated. Additionally, since two circulation paths each have an independent combustor, mixing of the tar-absorbing particle with the bottom ash can avoided. Running cost can be greatly reduced.
