Exhaust Gas Reforming of Methane in a Catalytic Microchannel Reactor

Abstract

Oxidative steam reforming (OSR) of methane is investigated under exhaust gas reforming conditions in a wallcoated catalytic microchannel reactor. The process is run over different combinations of Pt-and Rh-based catalysts, namely 0.2% (by weightIn each combination, coated catalysts are locked on the opposite walls of a rectangular microchannel to face each other. Parametric study is conducted in order to observe the effects of feed compositions (molar steam-to-carbon (H 2 O/C) and oxygen-to-carbon (O 2 /C) ratios) and temperature on methane conversion and on product distribution. The results show that methane conversion is enhanced with the increase in temperature and in the amounts of O 2 and H 2 O in the feed stream. When the temperature is raised from 600 to 700 °C, methane conversion is found to improve by ca. 25% in all catalyst configurations. Increasing H 2 O/C and O 2 /C ratios improved methane conversion at most by 7% and by 23%, respectively. H 2 production also increased with temperature, with the highest increase of 5% is observed over the 2%Rh/Al 2 O 3 −2%Rh/Al 2 O 3 combination. Higher O 2 /C ratios improved the extent of methane total oxidation but decreased H 2 production. The catalyst combination involving 2% Rh/Al 2 O 3 coated oppositely onto the inner walls of the microchannel is found to exhibit the best performance in terms of methane conversion and H 2 and CO amounts in the product stream. A 10% increase in methane conversion is observed either by changing the Pt content from 0.2% to 2% or by replacing 2%Pt with 2%Rh. The results show that Rh is superior to Pt in terms of oxidation and steam reforming activities.

Oxidative steam reforming of glycerol to synthesis gas in a microchannel reactor

“…Despite the presence of oxidative conditions, exothermic temperature rise was not observed and isothermal conditions were satisfied in the tests due to small reactant flow rates and catalyst loadings, and presence of metallic housing that helped in immediate suppression of any possible hot-spots. This behavior was in alignment with the previous studies that involved similar catalytic microchannel reactor configurations for oxidative conversion of methane [16,31]. Moreover, in both coated and packed microchannel configurations pressure drop remained negligible, which was confirmed by the pulse-free flow of the reactor effluent stream that was monitored by means of a soap-bubble meter.…”

“…Considering that CO 2 was a primary product of total oxidation, increased amounts of inlet O 2 seemed to promote oxidative conversion of H 2 , C 1 -C 2 hydrocarbons and other carbon containing surface species. Possibility of this route became stronger by the inherently high activity of Rh/Al 2 O 3 towards total oxidation of light hydrocarbons that was reported in previous studies [31,38].…”