Influence of flow regime on the decomposition of diluted methane in a nitrogen rotating gliding arc

Abstract

This work reports the operation of rotating gliding arc (RGA) reactor at a high flow rate and the effect of flow regimes on its chemical performance, which is not explored much. When the flow regime was changed from transitional to turbulent flow (5rightarrow 50~hbox {SLPM}), operation mode transitioned from glow to spark type; the average electric field, gas temperature, and electron temperature raised (106rightarrow 156~hbox {V}cdot hbox {mm}^{-1}, 3681rightarrow 3911~hbox {K}, and 1.62rightarrow 2.12~hbox {eV}). The decomposition’s energy efficiency (eta _E) increased by a factor of 3.9 (16.1rightarrow 61.9~hbox {g}_{{text{CH}}_{4}}cdot hbox {kWh}^{-1}). The first three dominant methane consumption reactions (MCR) for both the flow regimes were induced by text {H}, CH, and text {CH}_3 (key-species), yet differed by their contribution values. The MCR rate increased by 80–148% [induced by e and singlet—text {N}_2], and decreased by 34–93% [CH, text {CH}_3, triplet—text {N}_2], due to turbulence. The electron-impact processes generated atleast 50% more of key-species and metastables for every 100 eV of input energy, explaining the increased eta _E at turbulent flow. So, flow regime influences the plasma chemistry and characteristics through flow rate. The reported RGA reactor is promising to mitigate the fugitive hydrocarbon emissions energy efficiently at a large scale, requiring some optimization to improve conversion.