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

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 . [ABSTRACT FROM AUTHOR]