One-dimensional model for in situ coal gasification

Abstract

This report presents a calculational model that describes certain aspects of the in situ gasification process. The primary aim of this preliminary work was to predict and correlate reaction and thermal-front propagation rates and product-gas composition as a function of coal bed properties and process operating conditions. We restricted initial efforts to a one-dimensional transient Darcy flow in a permeable packed bed. The numerical calculations include a detailed description of the reacting systemchemistry (13 species), with appropriate reaction rates and overall heat and mass transport in the system. A comparison of calculated results with experimental data from a packed-bed combustion tube showed good agreement for reaction-zone propagation rates and produced-gas compositions. However, we believe the sensitivity of the calculations to other reaction-rate and transport-coefficient models needs to be investigated.