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对负载Pt催化剂的微圆管内CH_4的催化着火进行了实验研究,比较了三种点火方式下的催化着火温度,即:1)加热反应器外壁、2)预热进口气体、3)H_2辅助催化着火,确定了最优的点火方式,并采用CFD方法对H_2辅助CH_4催化着火的深层原因进行了分析,结果表明:点火方式1)具有最高的CH_4催化着火温度,方式2)的着火温度略低于1),而方式3)的着火温最低,特别是在较高的CH_4浓度条件下,H_2可以显著地降低CH_4催化着火所需要的温度,在CH_4的催化着火过程中,O_2占据催化活性中心(O(s)),抑制了CH_4的吸附,因此着火发生在较高的温度条件下;当掺入H_2以后,H_2的燃烧消耗O(s),为CH4的吸附提供了空位活性中心(Pt(s)),从而降低了CH_4的催化着火温度.
Catalytic ignition of CH_4 in micro-tubes loaded with Pt catalyst was studied. The catalytic ignition temperatures were compared among three ignition modes, namely: 1) heating the outer wall of the reactor, 2) preheating the inlet gas, and 3) After ignition, the optimal ignition mode was determined and the deep cause of H2-assisted CH4-catalyzed ignition was analyzed by CFD method. The results showed that ignition mode1) had the highest CH4 catalytic ignition temperature, and ignition temperature of mode2) was slightly lower In 1), while in mode 3), the ignition temperature was the lowest. Especially at higher CH 4 concentration, H 2 could significantly reduce the temperature required for CH 4 -based catalysis. During the catalytic ignition of CH 4, O 2 occupied the catalytic activity center (O (s)) inhibited the adsorption of CH 4, so the ignition occurred at higher temperature. When H 2 was added, the combustion of H 2 consumed O (s), providing a vacancy active center for the adsorption of CH 4 (s)), thus reducing the catalytic ignition temperature of CH 4.