A portable, sustainable, and efficient system and apparatus for breaking down processed solid plastic waste and other polymer-based feedstock into fuel oil, sustainable energy, carbon char, and other useful products. With minor modifications, biomass can also be treated. Distributed microwave heating sources and mechanical mixing effectively mix heat in a highly insulated reactor that protects the microwave components, makes fast pyrolysis possible, and thereby enables scaling down to compact and highly portable systems. Products include diesel, gasoline, propane, butane, and char. Product materials are distributed using tight temperature control and mechanical routing.