A reactor with two reaction zones (pyrolyzer and combustor) is developed, which is proposed for the thermal disposal of solid wastes, especially RDFs (refuse-derived fuels). A model RDF was used to evaluate the performance of the reactor. The RDF is continuously fed to the spouting-moving bed pyrolyzer in which the RDF partially combusts to supply heat for pyrolysis of the RDF at low temperature, then the pyrolysis product burns with secondary air at high temperature in the upper combustor. A special connector cascades the two parts to a vertical configuration, where secondary air is introduced. The effect of operating parameters, such as spouting air and auxiliary air, as well as secondary air flow rate on the pyrolyzer temperature, pyrolysis gas composition at different positions, combustor temperature, and emissions of CO and NOx in flue gas, are studied.