The conventional pyrolysis of waste plastics, carried out in a tank reactor or kiln, yields fuel oil with a wide boiling range. To improve the economic process of feedstock recycling of waste plastics, a new thermal process for fuel-gas production is proposed. Considering the role of sand as an effective heating medium and by using a reactor structure for suitably controlling the reaction temperature and reaction time, a new type of reactor equipped with a screw conveyor has been developed; this reactor is termed the moving-bed reactor. The formation of gaseous hydrocarbons was achieved at 82 wt % (pyrolysis) and 94 wt % (catalysis) in the operations research of the new process using polypropylene as feed.