Numerical Simulation study of Underground Coal Gasification using the CRIP method

Mojtaba Seifi, Zhangxing Chen, and Jalal Abedi

Underground coal gasification (UCG) is a process to convert unminable underground coal, especially in deep and thin coal seams, into combustible gases by gasifying the coal in-situ. The coal reacts with injected air or oxygen and steam, to form gases, liquids, and ash. The produced combustible gases can be used either as a fuel or as a feedstock. In this work, a three-dimensional numerical simulation of the UCG process is studied in terms of the heat and mass transport phenomena and chemical kinetics in a coal seam during coal combustion and by applying the controlled retracting injection point (CRIP) technique. The STARS module of the Computer Modeling Group software (CMG) is used in this study. The gas species flow rate, cavity shapes, cavities series, and temperature profiles in the coal seam during gasification are investigated. The main motivation behind this study is to provide a numerical simulation methodology by using a comprehensive porous media flow approach to understand the critical aspects of the UCG process.