Reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma

Abstract

In this work, a two-dimensional fluid model is built up to numerically investigate the reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma. The calculation results indicate that the electron collisions with CH4 are the key pathways to produce the neutral particles CH2 and CH as well as the charged particles e and CH3+. CH3, H2, H, C2H2, and C2H4 primarily result from the reactions between the neutral particles and CH4. The charge transfer reactions are the significant pathways to produce CH4+, C2H2+, and C2H4+. As to the neutral species CH and H and the charged species CH3+, the reactions between themselves and CH4 contribute to substantial losses of these particles. The ways responsible for losing CH3, H2, C2H2, and C2H4 are CH3 + H → CH4, H2 + CH → CH2 + H, CH4+ + C2H2 → C2H2+ + CH4, and CH4+ + C2H4 → C2H4+ + CH4, respectively. Both electrons and C2H4+ are consumed by the dissociative electron-ion recombination reactions. The essential reaction pathways of losing CH4+ and C2H2+ are the charge transfer reactions.

Numerical investigation on the CH4/CO2 nanosecond pulsed dielectric barrier discharge plasma at atmospheric pressure

“…With the emergence and development of advanced processing techniques, CH 4 has received extensive attentions and applications in such fields as nanomaterial synthesis, crop fertilization, and syngas (H 2 +CO) production. [1][2][3] Meanwhile, carbon dioxide (CO 2 ) lies in atmosphere, marsh gas, and oilfield associated gas, playing the significant role in both natural ecological balance and modern society operation by ways of photosynthesis, fuel combustion, and organic decomposition. 4,5 It is well known that CH 4 and CO 2 are undesirable greenhouse gases, so the simultaneous utilization of CH 4 and CO 2 is essential to ensure the energy security of fossil fuels and reduce the greenhouse effect caused by climate changes.…”

Numerical Investigations on Methane–Air Nanosecond Pulsed Dielectric Barrier Discharge Plasma-Assisted Combustion

“…The maximum heat production rate hits 3 W/cm 3 in methane−air combustion without plasma assistance, and it rises to 6.2 or 14 W/cm 3 in methane−air combustion with plasma assistance with an applied voltage amplitude of 9 or 10 kV. As the applied voltage amplitude increases from 11 to 13 kV, the maximum heat production rate varies around 2 W/cm 3 .…”

Non‐oxidative methane conversion in diffuse, filamentary, and spark regimes of nanosecond repetitively pulsed discharge with negative polarity

“…It is widely accepted that methane is activated by electron impact reactions and thermal reactions . The electrons are accelerated in the electric field, and frequently collide with methane or its products into vibrationally or electronically excited states, C x H y radicals (CH 3 , CH 2 , CH, C, and H), and ions (, , , CH + , and C + ) . Among these reactions, the electron dissociation reactions of the methane are the fundamental processes as shown in Equation , in which the electron threshold energy is 6.6–12 eV .…”