Coupled reforming of methane to syngas (2H2-CO) over Mg-Al oxide supported Ni catalyst

Abstract

We report bi-reforming and coupled reforming of methane with carbon dioxide, steam and/or oxygen to produce syngas over Ni supported on Mg-Al mixed oxide. The catalyst has been characterised in terms of specific surface area, TPR, XRD, TGA-DTG, SEM and TPO-MS analysis. Ni/Mg-Al mixed oxide exhibited Ni particle size range (11–30nm) with a mean of 20.7nm. Syngas H2/CO=2.0, suitable for methanol/Fischer-Tropsch fuel synthesis, has been achieved for both reactions (T=1048K, P=1atm). The impact of process parameters including temperature, feeding concentration and GHSV on conversion and H2/CO ratio has been demonstrated. The Ni catalyst suffered temporal activity decline in bi-reforming that can be linked to formation of carbon whiskers encapsulated Ni particles resulting in a loss of active sites. Coupled reforming delivered higher CH4 conversion and enhanced stability, but lower CO2 conversion than bi-reforming under similar conditions. The enhanced stability in coupled reforming can be attributed to lower carbon deposition on Ni particles due to combustion of carbon by oxygen.