Plasma activation of methane for hydrogen production in a N2 rotating gliding arc warm plasma: A chemical kinetics study

Abstract

In this work, a chemical kinetics study on methane activation for hydrogen production in a warm plasma, i.e., N 2 rotating gliding arc (RGA), was performed for the first time to get new insights into the underlying reaction mechanisms and pathways. A zero-dimensional chemical kinetics model was developed, which showed a good agreement with the experimental results in terms of the conversion of CH 4 and product selectivities, allowing us to get a better understanding of the relative significance of various important species and their related reactions to the formation and loss of CH 4 , H 2 , and C 2 H 2 etc. An overall reaction scheme was obtained to provide a realistic picture of the plasma chemistry. The results reveal that the electrons and excited nitrogen species (mainly N 2 (A)) play a dominant role in the initial dissociation of CH 4 . However, the H atom induced reaction CH 4 + H → CH 3 + H 2 , which has an enhanced reaction rate due to the high gas temperature (over 1200 K), is the major contributor to both the conversion of CH 4 and H 2 production, with its relative contributions of >90% and >85%, respectively, when only considering the forward reactions. The coexistence and interaction of thermochemical and plasma chemical processes in the rotating gliding arc warm plasma significantly enhance the process performance. The formation of C 2 hydrocarbons follows a nearly one-way path of C 2 H 6 → C 2 H 4 → C 2 H 2 , explaining why the selectivities of C 2 products decreased in the order of C 2 H 2 > C 2 H 4 > C 2 H 6 .

Carbon Nanosheets Synthesis in a Gliding Arc Reactor: On the Reaction Routes and Process Parameters

“…Therefore, the estimated temperatures represent for gas temperature in the two reactions. These numbers coincide with the reported gliding arc gas temperature in a range of 1000-4000 K [40,41]. Further, the gas temperatures from the reactor outlet were also measured, which were lower than 310 K in both of cases.…”

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

“…Both electron dissociation and thermal pyrolysis are able to produce the H radicals as Equations . When the gas temperature is high enough, the H radicals become so reactive that they can extract H atoms from the hydrocarbons (Equation ) and thus trigger a radical chain reaction, which explains the high‐conversion rate and hydrogen selectivity in the spark discharge …”

Selective Flotation of Pyrite from Arsenopyrite by Low Temperature Oxygen Plasma Pre-Treatment

“…The pre-treatment time of the oxygen plasma had a negative correlation with the flotation recovery. The reactions of excitation, dissociation and ionization of oxygen took place at the plasma ignition, through which the reactive species were produced [39]. With the increase in plasma pre-treatment time, more reactive species have the opportunity to bombard the mineral surfaces, thereby breaking the original covalent bonds of the crystals and promoting the oxidation and increasing the hydrophilic of mineral surfaces by binding O with Fe-, As-and S- [40].…”