Two-dimensional Numerical Simulation of Continuous Reverse-flow Oxidation of Ultralow Heating Value Coalbed Methane

Abstract In order to investigate the continuous reverse-flow oxidation of ultralow heating value coalbed methane, a two-dimensional mathematical mode for the continuous reverse-flow oxidation of ultralow heating value coalbed methane was set up. The software FLUENT was used to simulate the thermal structure of the oxidation bed and the effect of operating conditional parameters. The result indicates that: the temperature field of oxidation bed presents trapezium. There exists obvious difference in temperature at the both ends of oxidation bed, and it is helpful to preheat the fresh gas and recover the flue gas heat. Comparing with the conventional porous media combustion, the continuous reverse-flow oxidation has lower peak temperature and outlet temperature, and the methane conversion rate remains high. With the increase of methane concentration, the high-temperature zone widens, the both of temperature and outlet temperature rise, and the reaction area moves to inlet continuously. As the inlet velocity increases, the peak of temperature and outlet temperature both rises significantly, and the reaction area shifts toward to outlet continuously. With the increase of wall heat loss, the peak of temperature and the whole temperature of oxidation bed both reduce, the high-temperature zone becomes narrow obviously, and the reaction area is far away from the inlet.