Parallel electrodes gliding plasma: Working principles and application in dry reforming of methane

Abstract

A parallel electrodes gliding plasma (PEGP) is developed and applied for the dry reformation of methane. It consists of a pair of parallel wire-plate electrodes that is fed by repetitive nanosecond electrical pulses and placed into a divergent acoustic waveguide. The waveguide conducts the plasma-produced acoustic shock waves forward, causing sparking at the low pressure moving nodes of the waves. Consequently, PEGP provides a high plasma mobility within the volume of the parallel electrodes where constant reduced field (E/N), optimized for molecular dissociation, is applied. This is in contrast to the case of the conventional glide plasma, where E/N covers a range of values. Besides, the energy of the mobile plasma is mostly dissipated in the layers of fresh reactants gas, instead of overheating or dissociating the products. Consequently, higher conversion rates and energy efficiencies are obtained. The performances of PEGP and different pulsed plasmas, are examined and compared in this study. Conversion rates of almost 50% for both reactants (CO2, CH4) with ECE exceeding 70%, at temperature of about 100 °C, are provided by PEGP. The cold PEGP has comparable conversion performance with the high temperature thermal plasmas while performs much better compared to the other reported cold plasmas.