Plasma Reforming for H2-Rich Synthesis Gas

Plasma has been used in fuel conversion and combustion systems for over a century; however, only in the recent decades has non-thermal plasma and the idea of a plasma catalysis effect been investigated as a possible means to enhance or replace traditional thermal or catalytic reforming systems. Plasma is described as the fourth state of matter, and this refers to the chemical, thermal, or electrical breakdown of a gas, often forming a luminous ionized state comprised of a mix of particles: positive and negative ions, electrons, radicals, and neutral gas atoms and molecules. Plasmas are categorized as thermal or nonthermal, with the primary difference being how energy is deposited into the plasma gas stream. Both thermal and non-thermal plasmas have many commercial and industrial applications. The most effective plasma discharges used in fuel conversion applications have the ability to simultaneously provide high electron temperature and density with a high degree of non-equilibrium to support selective chemical processes. Such plasma discharges include gliding arc plasmas (transitional arcs) and microwave plasmas. This chapter presents a brief introduction of each type of discharge to highlight its characteristics and demonstrate the benefits for fuel conversion applications. There are several interesting research areas still being explored within the realm of plasma-assisted fuel conversion that may hold great promise in the near future.