Plasma catalytic steam reforming of a model tar compound by microwave-metal discharges

Electrical discharges triggered by microwave radiation on certain metals can induce remarkable heating and plasma effects that open up new opportunities for enhancing chemical reactions in a variety of fields through plasma catalysis. In this work, the steam reforming of toluene, a model tar compound, was investigated in a microwave-metal (MW-metal) discharge reactor by using nitrogen as carrier gas. Compared with MW-metal discharge cracking of toluene where most carbon ends up as soot, the plasma-catalytic steam reforming can effectively convert toluene into useful syngas with the in-situ elimination of soot formation and an overall toluene conversion efficiency of over 88%. The optimal S/C ratios for the reforming of medium-concentration toluene (17-25 g/Nm(3)) and high-concentration toluene (100 g/Nm(3)) were 1.7 and 2 respectively, with the outcome of rare soot formation and syngas yielded as main product. The distinguished advantage of MW-metal discharge steam reforming in converting toluene efficiently to syngas product with in-situ soot elimination demonstrates a giant application prospect in tar elimination in biomass gasification processes.