Steam reforming of methane over Ni catalyst in micro-channel reactor

A comprehensive study on the catalytic performance of Ni catalyst to implement millisecond steam reforming of methane (SRM) reaction in micro-channel reactors was conducted in this work. A new method to manufacture the metal–ceramics complex substrate as catalyst support was presented, that is, a layer of nano-particles, α-Al2O3, was thermally sprayed on a metallic substrate, usually FeCrAlloy. Ni or Rh catalyst was then impregnated on the substrate, forming firm and active catalyst coatings. The fall-off rate of the catalyst can be neglected after the plates experienced the high-temperature SRM reaction, showing the reliability in long-term use and the excellent catalytic performance for SRM reaction in micro-channel reactors. In comparison with the expensive Rh catalyst, Ni also showed wonderful performance to catalyze the SRM reaction in micro-reactors within milliseconds. Using the appropriate reactor design, CH4 conversion reached above 90% when the residence time was as short as 32 ms for catalyst loading of 6.8 g/m2. When the residence time was longer than 100 ms, CH4 conversion was above 98%. Besides, catalyst deactivation was not detected for 500 h on stream with S/C ratio of 3.0, and for 12 h with S/C of 1.0 as well. Extensive characterizations on these Ni catalyst plates using XRD, SEM, TEM and XPS demonstrated that Ni catalysts prepared in this work did not show any sign of deactivation after being used in the micro-channel system under high-temperature operation.