Numerical study on thermal oxidation of lean coal mine methane in a thermal flow-reversal reactor

This paper presents a three-dimensional numerical investigation on thermal oxidation of lean coal mine methane in a thermal flow-reversal reactor by the finite volume method. The effects of channel length, feed methane concentration, inlet velocity and cycle time on the reactor behavior were analyzed. Results show that the temperature distributions and methane concentration profiles in the reverse-flow semicycle are mirror images of the ones in the forward-flow semicycle. Thus the cycle for the cyclic steady state is symmetrical. The maximum temperature of the reactor rises significantly with the increases of methane concentration and inlet velocity, and it is nearly unchanged with the increases of the channel length and cycle time. Long channel length, high feed methane concentration, low inlet velocity and short cycle time could achieve a wider high temperature zone in the reactor. The minimum feed methane concentration for self-maintained running rises dramatically with the decrease of channel length and the increase of inlet velocity, and it is almost not affected by the change in cycle time. For a desired minimum feed methane concentration of 0.18 vol.% when vin = 1 m/s, the required channel length should not be less than 1.8 m.