Brown coal conversion by microwave plasma reactions under successive supply of methane

Abstract

To develop an innovative method for directly converting brown coal to relatively important fuels and synthesis gases in a single step, while simultaneously upgrading the carbon content of the residue, microwave plasma technology was applied to the direct conversion of brown coal (Yallourn). Methane under reduced pressure was supplied through a quartz reactor into the irradiation zone and reacted with the coal bed placed downstream. Both the coal conversion and the carbon content of the residue were increased with an increase of irradiation time. The yield of oily products showed a maximum value (18 wt.%) at 2 min irradiation, and the fuels were composed mainly of aliphatic hydrocarbons in the range from C13 to C34. Furthermore, carbon monoxide and hydrogen accompanied by a molar fraction of < 16% of acetylene were mainly produced when the irradiation time was varied from 1 to 10 min.