Enhancement of coal char gasification using a pyrolyzer–gasifier isolated circulating fluidized bed gasification system

Abstract

In the present study, we attempted to promote the steam gasification of coal char at low temperatures (below 1173K). A novel circulating fluidized bed gasification reactor was developed. This reactor consisted of three units: a pyrolyzer, a gasifier, and a combustor. The main feature of the reactor was that the pyrolyzer was physically isolated from the gasifier. Such physical isolation of the pyrolysis zone (pyrolyzer) from the char gasification zone (gasifier) in the reactor can prevent char gasification from being inhibited by contact of the char with hydrogen gas or the tar vapor formed by pyrolysis. Therefore, char gasification was certainly promoted by the physical isolation of the pyrolyzer from the gasifier in comparison with the conventional gasification reactor, in which pyrolysis and subsequent char gasification proceed in one unit.