(220f) Recombination after the Plasma and Product Distribution

Plasma has proven to be an effective medium to promote highly endothermic chemical reactions with reasonable energy efficiency. Two notable examples are carbon dioxide splitting into carbon monoxide and oxygen, and nonoxidative methane reforming into acetylene and hydrogen. These reactions can be carried out with energy efficiencies, based on the enthalpy of reaction, in the range 20 to 50%, at high volumetric productivity. Understanding of the key plasma process parameters that are required to promote exothermic reactions, by contrast, is much less developed. In this presentation, the focus will be on the background temperature in the recombination zone following the plasma. The hypothesis is that a lower background temperature after the plasma promotes the formation of products from relatively exothermic reactions and suppresses products from relatively endothermic reactions. Results will be presented from an experimental test of this hypothesis using nonoxidative methane reforming as an example system.