Computer Modeling of Fixed Bed Underground Coal Gasification Using the Permeation Method

A two-dimensional computational model has been developed as a pilot study for the multidimensional simulation of fixed bed underground coal gasification (UCG). The analysis is based on the finite element method and incorporates a moving boundary algorithm to model the permeation linked vertical well in a forward gasification mode. In order to account for the motion of the combustion front with time, an immobilization transformation of coordinates technique is introduced in the finite element formulation. A numerical case study is included to illustrate the capability of the model. Predictions on temperatures, gas composition, pressure, and coal consumption in space and time are possible by using this model.