Performance and SEM characterization of Rh impregnated microchannel reactors in the catalytic partial oxidation of methane and propane

Two different reactor materials (Fecralloy, Nicrofer) have been investigated in the catalytic partial oxidation of methane and propane. The focus of the study was on the stability and applicability of the different reactor materials, in particular their alumina coating related to their catalytic performance. Both reactors were impregnated using a RhCl3 solution, yielding 6.3 and 4.6 mg of Rh deposited on the Fecralloy and Nicrofer, respectively.It is shown that high temperature calcination of Fecralloy established a stable alumina coating. This effectively increased the surface area of the reactor providing sites for the Rh particles. The reactor performance was stable with both methane and propane feeds. SEM images of the Fecralloy reactor revealed significantly larger Rh particles near the reactor exit as compared to inside the reactor.The Nicrofer was wash-coated with alumina using a sol–gel technique. SEM images of the Nicrofer reactor revealed the formation of Cr-layers and Cr-oxide structures covering the impregnated Rh particles. The Cr rich structures coating the Rh particles were found to be detrimental to the reactor performance, and the alumina wash-coating was consequently not successful at stabilizing the Nicrofer reactor material.Methane was found to be more difficult to activate than propane, as expected, but provided the benefit of no formation of C2+ components, with H2 and CO selectivities almost as high as with propane.