Mixed reforming of methane over Ni-K/CeO2-Al2O3: Study of catalyst performance and reaction kinetics

Syngas can be effectively produced by mixed reforming of methane (MRM). In this work, the performance of Ni-K/CeO2-Al2O3 catalyst in this process was investigated in a fixed-bed reactor in the 923-1073 K range. Both potassium and ceria are renowned for improving the performance of Ni catalyst in the reforming process. The influence of reaction conditions (viz. temperature, space time, feed composition and time-on-stream) on the conversion of two reactants CH4 and CO2, yield of the products H-2 and CO and the H-2/CO ratio in syngas were studied. At T = 1073 K and W/Q(0) = 0.17 g-h/L (here, W and Q(0) denote catalyst mass and volumetric flow rate of feed), conversions of CH4 and CO2 were 91.2 and 80.1%. When S/C ratio (or steam-to-carbon ratio) in feed increased from 0.2 to 0.5 mol/mol, H-2/CO ratio at T = 1073 K changed from 1.32 to 2.14 mol/mol. The catalyst performed stably for 50 h of time-on-stream. Reaction kinetics was studied between 973 and 1073 K and power law kinetic model was suggested. The apparent activation energy values for consumption of CH4 and CO2 were found to be 33.3 and 45.5 kJ/mol, respectively. This work is expected to aid catalyst development and reactor design for the MRM process. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.