Catalytic deoxygenating characteristics of oxygen-bearing coal mine methane in the fluidized bed reactor

The catalytic deoxygenating experiment of oxygen-bearing coal mine methane (CMM) was carried out in a bench-scale fluidized bed reactor with the spherical Cu-based catalyst. The effects of the bed temperature, the particle size and the space velocity were investigated on the oxygen removal efficiency and CO2 selectivity. The rise of bed temperature could promote the oxygen conversion due to the high activity of the catalyst. The O2 conversion could reach more than 95% when the temperature was above 450°C. The smaller particle size was beneficial to the CO2 selectivity of the catalyst because of the decrease in inner diffusion resistance. The lower space velocity also could improve the oxygen removal efficiency when the bed temperature was below 450°C although the improvement almost disappears above 450°C due to the increase catalytic combustion rate. Additionally, by adjusting the CH4/Air ratio, the catalytic deoxygenation adaptability of the fluidized bed reactor and the catalyst were evaluated for the variable oxygen content in CMM. The results indicate that the process has a perfect oxygen removal performance with the O2 concentration less than 0.2% and the CO2 selectivity more than 98% for the O2 content from 5% to 15% in the simulated CMM.