Combined silicon carbide and zirconia open cell foams for the process intensification of catalytic methane combustion in lean conditions: impact on heat and mass transfer

For catalytic process intensification, a series of open cell foams (OCFs) made of silicon carbide (SiC) and zirconia (Zir) with pore density of 30 ppi coated with 3 wt.% PdO/Co3O4 as catalyst were combined together and tested toward methane oxidation in lean conditions. In each combination, the SiC OCF was positioned in the reactor on the inlet side of the reactant gases followed by the Zir OCF. The reactor was fed at different weight hourly space velocities (WHSV, 30 and 90 NL h−1 gcat−1) and inlet methane concentrations (0.5 and 1 vol.%). The best results are obtained with the combination where two supports of same length but with different thermal conductivity (higher at the inlet of the reactor, SiC, and lower at the outlet, Zir) are used in series. For all OCF combinations, mass transfer effects were evaluated using the characteristic resistances (kinetic, internal and external mass transfer). The external and internal heat transfer effects were analyzed using the Mears and Anderson criteria. Furthermore, a comparison in terms of volumetric heat transfer coefficient and heats of removal/reaction was performed.