A low temperature plasma reactor for the treatment of particulate material. A housing is provided having an exit for treated material. Within the housing, the particulate material, and any desired additional reactants, undergo thermo-chemical reaction while being subjected to cyclonic action. The particulate material migrates or is driven toward the housing walls as it travels through the housing toward the housing exit. A plasma generator subjects that material that passes through the housing exit to plasma action. In a preferred embodiment, the housing includes a first portion wherein the cyclonic conditions are established, a throat portion through which treated material exits the housing and an adaptive portion extending between the first portion and the throat portion. An offgas duct withdraws gas and entrained particulate material generally at the junction of the first and adaptive housing portions while the plasma generator establishes a thermal barrier to the passage of entrained particulate material from the throat portion. The offgases may be employed in cogeneration while the inlet gases, by which cyclonic action is established, may have their constituents controlled with cogeneration in mind.