CFD SIMULATION OF UNDERGROUND COAL GASIFICATION

Abstract

An unsteady state-three-dimensional packed bed model has been developed to estimate gas production and cavity growth in underground coal gasification. The model, incorporates a three-dimensional unsteady-state cavity growth sub-model and models mass transfer and heat transfer from the bulk gas to the coal seam. Simulations with the model reveal that the gas calorific value is , sensitive to coal reactivity and the exposed reactive surface area per unit volume in the channel. A comparison of model results with Perkins et. al. (2008), who has been develop a pseudo-one-dimensional open channel show that the model can make good predictions of the gas production and composition under a range of different operating conditions, including operation with air and steam/oxygen mixtures. Further work is required to determine whether the model formulation is also suitable for simulating critical behavior of cavity growth