The kinetic studies of direct methane oxidation to methanol in the plasma process

Abstract

The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma process yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO(2) as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO(2) were produced in plasma process than in thermal process. The selectivity of CO and CO(2) by plasma was 47% and 20%, respectively. Ethane (C(2)H(6)) was detected as the only higher hydrocarbon with a significant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.