含氧煤层气流化床催化燃烧脱氧特性研究

利用自制的铜基球形甲烷催化燃烧催化剂,在小型流化床反应器中对模拟含氧煤层气进行了流化床催化燃烧脱氧的实验研究,考察了床层温度、催化剂粒径、空速对脱氧效率和CO₂选择性的影响。结果表明,较高的反应床层温度使催化剂活性增强,进而提高催化脱氧效率。床层温度在450 ℃以上,脱氧效率可稳定保持在95%以上。较小的催化剂粒径降低了内扩散阻力对催化反应的影响,提高催化反应的CO₂选择性。床层温度在450 ℃以下时,降低空速可提高氧气转化率,但温度高于450 ℃时,脱氧反应速率加快,空速变化对脱氧效率影响不明显。此外,通过调节CH₄/Air比例模拟不同含氧量的煤层气,考察流化床反应器及催化剂对含氧煤层气中O₂浓度变化的适应性。模拟含氧煤层气中氧气体积分数在5%~15%,该催化剂均表现出高的脱氧活性和选择性,反应器出口气体中氧气体积分数低于0.2%,CO₂选择性高于98%。

Catalytic deoxidization characteristic 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 raising bed temperature could promote the O₂ conversion due to the high activity of the catalyst. The O₂ conversion could reach more than 95% when the temperature was above 450 ℃. The smaller particle size was beneficial to the CO₂ selectivity of the catalyst because of the decreasing inner diffusion resistance. The lower space velocity also could improve the O₂ removal efficiency when the bed temperature was below 450 ℃ although the improvement almost disappears above 450 ℃ due to the increasing catalytic combustion rate. Additionally, by adjusting the CH₄/Air ratio, the catalytic deoxygenation adaptability of the fluidized bed reactor and the catalyst was 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.