Numerical model of coal gasification in a packed bed

Modelling Underground Coal Gasification—A Review

“…Initially, around 1976, several 1D transient packed bed models [42,47,48] with the finite-difference approach were developed in parallel, supported by the Lawrence Livermore National Laboratory (LLNL) program. However, there is no basic difference between the models developed by Thorsness et al [48] and Thorsness and Rozsa [42].…”

“…On the other hand, Winslow [47] did not approximate any stationary phase for the basic conservation equation, although he followed the physical and chemical model of Thorsness et al [48]. The following governing equations for mass and energy balance for both the gas and solid phases were used by Winslow [47]:…”

“…Winslow [47] also followed their work, except using a different numerical solution scheme. Thorsness et al [48] considered all the main reactions for gasification (reaction 1 to reaction 10); however, for homogeneous reactions, only the water-gas shift reaction was considered by Winslow [47].…”

“…Thorsness et al [48] considered all the main reactions for gasification (reaction 1 to reaction 10); however, for homogeneous reactions, only the water-gas shift reaction was considered by Winslow [47]. Although, for convenience, most of the researchers represent char as a molecule containing one carbon, they considered the chemical formula of char and dry coal as CH a1 O b1 and CH a2 O b2 , respectively, where the composition parameters a1, b1, a2, b2 depend on the type of coal (usually obtained from the ultimate analysis).…”

“…In their models, the fluid flow was described by the Darcy equation, in which permeability was set to change with the extent of the reactions. From the experimental data of drying and pyrolysis of subbituminous Wyodak coal, they formulated a functional relationship relating permeability to porosity that was used later by a number of researchers [12,47,50] who developed their model using subbituminous coal. The relationship is as follows:…”