Chapter 3 - The Kinetics of Gasification and Reactor Theory

Abstract

The kinetics of coal gasification is a subject of intensive investigation. Despite this, the results of such investigations have to date flowed into the design procedures for commercial gasification reactors to only a limited extent. This chapter discusses kinetic theory wherein the basic ideas and an indication of how and where appropriate application of kinetic theory could help in the design of future reactors are explored. In the section on kinetics, devolatilization, volatiles combustion, and char gasification are discussed. In the coke oven, a batch of coal is indirectly heated via the side walls in a relatively flat vertical oven where devolatilization takes place. Such a batch process can also be made semi-continuous, as is the case in a coal stove for domestic use and a moving-bed gasifier or fully continuous, as in large-scale grate-type furnaces as applied in power stations and industry. Subsequent section discusses plug flow reactors (PFR) and continuously stirred tank reactors (CSTR). Following this, applications to reactor design are explained. Applications are emerging where their incorporation into computational fluid dynamics (CFD) is proving to be of practical material benefit.