Entrained-bed coal gasification modelling

A mathematical model was developed to simulate the Texaco Inc. Downflow Entrained Bed Pilot Plant Gasifier (5 ft dia, 20 ft. long steel vessel) with coal liquefaction residues as feedstocks. The gasifier was conceptually divided into three zones; the pyrolysis and volatile combustion zone, the gasification and combustion zone, and the gasification zone. The gas phase was assumed to be completely mixed at the entrance region followed by a region approximating plug flow. The solid phase was assumed to be a plug flow throughout the reactor. Temperature and concentration profiles along the reactor were obtained by solving the material and energy balances and taking into consideration the gasification kinetics, the transport rates, and the hydrodynamics of the gasifier. Good agreement was obtained between computations from the proposed model and the experimental pilot-plant data. Sensitivity of the parameters used in the model was tested and optimum operating conditions were determined by simulating reactor performance under various operating conditions. 21 references.