Effect of Contact Time on Carbon Deposition and Catalytic Activity of Nickel Alumina Catalysts for Dry Reforming of Methane

Dry reforming of methane (DRM) reaction is advantageous in producing syngas with a low H-2/CO, relevant to many industries. Effect of contact time on catalytic activity and carbon deposition is studied for DRM using Ni-Al catalysts, along with the effect of metal loading, reaction temperature, and reactant partial pressure (CO2/CH4). Maximum CH4 conversion (58 %) and CO2 (59 %) were achieved at a higher contact time of 4.009 kg-cat . h/kg(CH4). A maximum of 46 % CH4 conversion was achieved at 1023 K with a contact time of 0.134 kg-cat . h/kg(CH4). Higher CH4 and CO2 conversion were achieved with an excellent H-2 and CO yield due to the RWGS reaction with increased metal (Ni) loading (10-30 wt . %). When the reactant partial pressure (CO2) changed from 0.1-0.3, the CH4 conversion increased whereas CO2 conversion decreased. FESEM images revealed the formation of whisker-like carbon fibers for all loadings. For the best syngas output and stability in a Ni-based catalyst, a combination of a basic support (alumina) at a higher contact time (similar to 4.009 kg-cat . h/kg(CH4)) and a CO2/CH4 ratio of 1-1.5 at a moderate temperature of 873 K may provide best CO2 adsorption with minimal coking.