A pyrolyzer capable of generating synthesis gas from carbon-based feedstock comprises an oven including an oven shell defining an interior and at least one conveyor configured to move the feedstock through the interior from a feed inlet to a discharge outlet. An outer shell surrounds the oven shell defines a space between the oven shell and the outer shell and a plurality of longitudinally extending dividers are connected to the outer shell and span to the oven shell within the space so as to define multiple temperature control zones therein where each temperature control zone includes one or more heaters.