基于过渡金属氧化物载氧体的煤矿通风瓦斯处理性能

采用反应管对基于过渡金属氧化物载氧体的煤矿通风瓦斯(VAM)处理性能展开了研究.结果表明,经活化后的三种载氧体均能将CH4完全转化为CO2,其活性顺序为CuO60/γ-Al2 O3>NiO60/γ-Al2 O3>Fe2 O360/γ-Al2 O3;基于CuO60/γ-Al2 O3的CH4转化率随空速的增加而减小,随CuO负载量和床层温度的升高而增大;煤矿通风瓦斯中的CH4浓度越低,CH4转化率达到90%所需的床层温度就越低;对活性物质低分散高负载的CuO60/γ-Al2 O3和活性物质高分散低负载的CuO5.5/γ-Al2 O3两种CuO/γ-Al2 O3系载氧体进行了比较,发现两种载氧体的CH4转化机理均包含有化学链燃烧和催化燃烧两种机理,基于催化燃烧机理的CH4转化率在一定温度下存在极大值,当床层温度高于该极大值温度时,化学链燃烧对CH4转化率的贡献明显大于催化燃烧对CH4转化率的贡献;相同条件下,CuO5.5/γ-Al2 O3的初期活性优于Cu60/γ-Al2 O3,但CuO60/γ-Al2 O3的活性稳定性优于CuO5.5/γ-Al2 O3.

Performance of ventilation air methane combustion over transition metal oxide oxygen carriers

The performance of combustion of ventilation air methane ( VAM) over transition metal oxide oxygen carriers was stud-ied through experiments with using tube reactors. The results show that the activity of activated oxygen carriers in converting CH4 to CO2 is as follows:CuO60/γ-Al2 O3 >NiO60/γ-Al2 O3 >Fe2 O360/γ-Al2 O3 . CH4 conversion based on CuO60/γ-Al2 O3 decreases with increasing gas hourly space velocity, but increases with increasing bed temperature and CuO loading. The lower the initial CH4 con-centration of ventilation air methane, the lower is the temperature for the CH4 conversion of 90%. There are catalytic combustion mechanisms and chemical-looping combustion mechanisms for CH4 combustion over both CuO60/γ-Al2 O3 , for which dispersion of the active component is low but loading is high, and CuO5. 5/γ-Al2 O3 , for which dispersion of the active component is high but loading is low. There exists a maximum for CH4 conversion based on the catalytic combustion mechanism at some temperatures, and when the bed temperature is higher than this temperature, the contribution of chemical-looping combustion is greater than that of catalytic com-bustion. The initial activity of CuO5. 5/γ-Al2 O3 is higher than that of CuO60/γ-Al2 O3 , while the stability of CuO60/γ-Al2 O3 activity is better than that of CuO5. 5/γ-Al2 O3 activity under the same conditions.