Synthesis Gas from Methane by Using a Plasma-Assisted Gliding Arc Catalytic Partial Oxidation Reactor

Abstract

In this work, the potential for the catalytic partial oxidation (CPOX) of methane (CH4) to produce synthesis gas (H2 and CO) was studied both experimentally and thermodynamically at a fixed pressure (1 bar) and electric power (0.3 kW). The investigations were performed in a partially adiabatic plasma-assisted (nonthermal) Gliding Arc (GlidArc) reactor, using a Ni-based catalyst. Two cases were studied: in the first, normal air (molar ratio of O2/N2 = 21/79) was used, whereas enriched air (O2/N2 = 40/60) was utilized in the second. The individual effect of the O2/CH4 molar ratio, gas hour space velocity (GHSV), and bed exiting temperature (Texit) was studied for both cases. The main trends of the CH4 conversion, the synthesis gas yield, and the thermal efficiency of the reactor based on the LHV (lower heating value) were analyzed and compared, and any deviations from equilibrium could be explained by temperature gradients and an irregular gas flow. In the findings from the studies, the results revealed that an H2/CO ratio of 2 could be obtained. For the normal air case, an optimal value of the O2/CH4 molar ratio of 0.7, a GHSV of 1.8 NL/(gcat.h), and a maximum temperature (Tmax) of 1065 °C were good reforming choices, whereas for enriched air, these values were 0.7, 1.8, and 1105 °C, respectively.