微细通道内甲烷部分催化氧化的反应特性

Investigation on the reaction characteristics of methane catalytic partial oxidation in a micro-channel

基于详细基元反应机理,对微细通道内Rh催化剂表面低浓度CH4部分催化氧化的反应特性进行了数值研究,重点考察了进口温度、CH4/O2体积比以及H2O对CH4部分催化氧化的影响。结果表明:在Rh催化剂表面,CH4的反应为动力学控制,而O2的反应为扩散控制;由于O2的高反应性,CH4首先与O2发生氧化反应,完全氧化产物和部分氧化产物均有生成;当O2被消耗以后,CH4与H2O发生重整反应,而CO2的重整反应没有发生;C/O体积比的增加会导致重整区积碳量的增加,从而CH4的转化率以及部分氧化产物的生成量降低,甚至重整反应停止;添加H2O能够有效地抑制积碳,并促进H2和CO2的生成。

The reaction characteristics of fuel-lean CH4 catalytic partial oxidation over Rh are investigated numerically in a micro-channel,by using detailed elementary mechanism,focusing on the effects of inlet temperature,equivalence ratio of CH4/O2 and added H2O on catalytic partial oxidation of CH4.The results show that over Rh surface reaction of CH4 is kinetically controlled,while that of O2 is controlled by mass transport.Duo to the high reactivity of O2,CH4 is firstly oxidized and both complete and partial oxidation products are generated.After O2 is consumed,steam reforming begins,however,CO2 reforming does not appear.Increase of the equivalence ratio of C/O leads to increase of carbon deposition at reforming zoon,as thus both conversion of CH4 and production of syngas decrease,even the reforming process is stopped.The added H2O could dramatically inhibit carbon deposition,and promote the formation of H2 and CO2.