A simple process modelling for a dry-feeding entrained bed coal gasifier

Abstract

A dry-feeding entrained bed coal gasifier was numerically modelled by simultaneously solving the rate equations for chemical reactions of the solid and gas phases. This model describes simplified physical and chemical processes in the entrained bed coal gasifier. Chemical reaction processes for coal gasification and combustion are considered along with the simplified gas flow passage in the reactor, so that progress of reactions at the designated spatial location is represented. Gasification phenomena of coal particles were separated into devolatilization, gas-phase, and solid-phase reactions. Coal gasifier geometry was simplified to a pseudo-two-dimensional (pseudo-2D) reactor model based on the 1D plug flow concept. The dimension in the pseudo-2D model was conceptually divided by considering the recirculation effect. As a result, carbon conversion, cold gas efficiency, and temperature distribution were obtained at variable oxygen to coal mass ratio, steam to coal mass ratio, and operating pressure. Operating conditions could be appropriately controlled by knowing the degree of reaction in the reactor.