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

Abstract

AbstractThis 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 ($$5\rightarrow 50~\hbox {SLPM}$$ 5 → 50 SLPM ), operation mode transitioned from glow to spark type; the average electric field, gas temperature, and electron temperature raised ($$106\rightarrow 156~\hbox {V}\cdot \hbox {mm}^{-1}$$ 106 → 156 V · mm - 1 , $$3681\rightarrow 3911~\hbox {K}$$ 3681 → 3911 K , and $$1.62\rightarrow 2.12~\hbox {eV}$$ 1.62 → 2.12 eV ). The decomposition’s energy efficiency ($$\eta _E$$ η E ) increased by a factor of 3.9 ($$16.1\rightarrow 61.9~\hbox {g}_{{\text{CH}}_{4}}\cdot \hbox {kWh}^{-1}$$ 16.1 → 61.9 g CH 4 · kWh - 1 ). The first three dominant methane consumption reactions (MCR) for both the flow regimes were induced by $$\text {H}$$ H , CH, and $$\text {CH}_3$$ CH 3 (key-species), yet differed by their contribution values. The MCR rate increased by 80–148% [induced by e and singlet—$$\text {N}_2$$ N 2 ], and decreased by 34–93% [CH, $$\text {CH}_3$$ CH 3 , triplet—$$\text {N}_2$$ 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 $$\eta _E$$ η 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.