Dry reforming of methane using a novel microreactor fabricated from stacking of stainless steel wire-mesh support catalysts

Abstract

We fabricated a novel microreactor with stainless steel wire-mesh supports coated with Ni-based hydrotalcite catalysts for dry reforming of methane (DRM) reaction. Catalytic performance and long-term stability of microreactor was tested by stacking the stainless steel wire-mesh support catalysts to allow parallel and crosssectional flow to stacking configurations. Conversion rates of CH4 and CO2 were measured and found to be 92% and 95% respectively, and syngas ratio of 0.92 was obtained. Only a small decrease of about 3-4% in conversion rates was observed after 100 h of reaction which could be due to whisker like carbon formation as carbon nanofibers (CNFs). Investigation of spent catalysts revealed that surfaces of support catalysts were not fully covered with CNFs, leaving active sites for reactant gases with little effect on long-term stability. In addition to CNFs, in situ formation of & gamma;-Al2O3 flakes were obtained during long-term DRM reaction from the parent FeAl powder that was used for annealing of stainless steel wire-mesh supports to increase the adhesion of hydrotalcitederived spinel catalysts. Effect of & gamma;-Al2O3 flakes on microreactor's performance turned out to be very useful because sites of & gamma;-Al2O3 flakes further prevented the deposition of carbon on surface and acted as active sites for reactant gases. Moreover, stacking of stainless steel wire-mesh support catalysts for parallel and cross-sectional flow configurations caused the better mixing of reactant gases due to the tortuosity of the narrow porous microstructure of the support. The excellent throughput was verified by numerical calculations using CFD simulations.