2-D Modeling of Underground Coal Gasification (UCG)

S. Mahajani[1], S. Srikantiah[1], G. Samdani[1], A. Ganesh[1], P. Aghalayam[2]
[1]Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
[2]Indian Institute of Technology Madras, Chennai, India

UCG is a process which converts coal to syn gas at the underground coal seam itself. UCG can help meeting the rising energy demand by utilizing coal resources that otherwise would be too deep, or of poor quality, or simply not economical to mine. As UCG takes place, a cavity is formed underground in the coal seam which grows three-dimensionally. The objective of this work is to develop a two-dimensional model of the cavity to analyze its growth and product gas composition. COMSOL Multiphysics® is used to simultaneously solve momentum, mass and energy balance equations taking into account both diffusive and convective transport. The model can foresee the growth of the cavity even after it has hit the overburden, which will be the reality for the UCG of thin coal seam.