Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-IV-16and MCP3) was 1.6 and 2.4 times respectively lower than that with foamed copper plates(MCP2). Specific hydrogen production (relative to the catalyst mass) for MCP1 and MCP3was 1.6 and 1.2 times respectively lower than that for MCP2 due to lower catalyst mass inMCP3. Thus, from the practical standpoint, foamed copper is the best material formicrochannel plates used in the above microreactor (then comes foamed nickel).In the high-temperature region (400-450 °C), the SMR process probably goes throughhydrolysis of methylformate (the activation energy of the reaction is 132 kJ/mole) and doesnot depend on the microchannel plate material where a catalyst is deposited. The reactionorder α =0.5 does not also depend on the type of microchannel plates. For comparison, theactivation energy of the SMR process on the copper catalyst is lower than100 kJ/mole.Long-term tests showed that stability of Zn/TiO 2 catalyst supported on the differentmicrochannel plates in the SMR process depends on the material of the microchannel plateused. The highest operation stability of the catalyst was observed for the foamed coppermicrochannel plates. Thus, during a 160-hour continuous operation of a microreactor suppliedwith the foamed copper microchannel plates, the initial methanol conversion of 80%decreased by 8%. During 500-hour tests, the methanol conversion decreased by 32%. Themain reason of the catalyst deactivation is sintering of zinc microparticles which areresponsible for the catalyst activity, at that the rate of the catalyst deactivation directlydepends on heat conductivity of a material of the microchannel plates. It was shown thatactivity of the deactivated catalyst can be restored by annealing it in air. An increase in theconcentration of water and addition of oxygen in the inlet mixture improves the catalystactivity and reduces its deactivation.425