PLASMA TECHNOLOGY UTILIZED IN NATURAL GAS CHEMICAL ENGINEERING
With large increases in natural gas reserves proven worldwide, it can be expected that natural gas will play an increasingly important role in energy and chemicals supplies in the 21st century. Methane is used as a fuel for industrial and residential heating, However, much more methane is produced than is required for this purpose and it may be commercially advantageous to convert methane into industrial chemicals. Selective activation of C-H bonds has been the goal of researchers in heterogeneous and homogenous catalysis for over 50 years. Selective reaction of saturated hydrocarbons like methane is difficult due to the similar high dissociation energy of activation. Plasma chemical processing is a promising route for synthesis of chemicals that have high activation energies, because very high energy can be supplied to the plasma and many kinds of reactive particles, electrons, free radicals, ions metastable species and photons, are produced in a plasma chemical processing system. This paper reviews the general situation on the thermal plasma decomposition of methane into acetylene,cold plasma catalytic conversion of methane into C 2, methanol and formaldehyde etc. The cold plasma utilized natural gas chemical engineering is discussed from process, reactor, concerted catalysis, reaction mechanisms and reaction dynamics in detail. However, the elucidation of the reaction mechanisms of reactions in the plasma is largely impeded due to the complex nature. Among all of the plasma generated species, free species are believed to be most important for chemical reactions. Extensive research has to be done in order to reasonably understand the elementary reactions.