Supersonic Hybrid Non-equilibrium Plasma Reactor for Co-Production of Hydrogen and Value-Added Solid Carbons from Methane*

The increasing concern of climate change requires immediate action to reduce CO₂ emissions from directly burning fossil fuels. At the same time, the recent increase of renewable electricity and the need of large scale electricity storage provide a great opportunity to produce hydrogen and valuable carbon from natural gas by taking advantage of its abundant resource. The predominant commercial method for production of hydrogen and carbon from natural gas is the high temperature thermal cracking process. However, the thermal cracking method has low yield and produces less valuable carbon but large amounts of polluting emissions. The objective of this work is to develop and optimize an innovative supersonic hybrid non-equilibrium plasma reactor for efficient and tunable co-production of hydrogen and value-added solid carbons with negative CO₂ footprint. The reactor for controlled methane reforming and H₂/carbon synthesis is designed and assembled. Plasma modeling shows that a pulsed gliding arc can reach to 4000 K for transient chemical reforming. Supersonic nozzle provides rapid reaction quenching to enable non-equilibrium chemical synthesis to achieve higher yield and selectivity.