Oxidation of lean methane by dielectric barrier discharge plasma and Mn–Ce catalyst

Abstract

The synergistic dielectric barrier discharge plasma and Mn-Ce catalysts are employed to facilitate the low temperature and highly efficient oxidation of lean methane. The effect of the catalyst alone, plasma alone, and their synergistic effect on CH4 conversion are experimentally analyzed. It shows that the CH4 conversion rate under plasma catalysis is more than three times that of catalyst alone and plasma alone, with a maximum of 66.7% at 375 °C and 21 W, revealing a significant synergistic effect of plasma catalysis. The influence of Mn/Ce mass ratios (11Mn/Ce and 45Mn/Ce) and operational conditions (CH4/O2 molar ratio, preheating temperature, and discharge power) on CH4 conversion by plasma catalysis are also investigated. The CH4 conversion rate increases with the decrease of the CH4/O2 molar ratio and the increase in preheating temperature and discharge power. Meanwhile, the Mn/Ce mass ratio affects the CH4 oxidation and the synergistic effect of plasma catalysis. The oxidation activity of the 11Mn/Ce catalyst is mostly affected by the power at the preheating temperature below 325 °C. However, the 45Mn/Ce catalyst is affected by both preheating temperature and power. In addition, as the discharge power increases, the CH4 conversion rate exhibits a linear increase for 11Mn/Ce but exponential for 45Mn/Ce.