PURPOSE: To improve the heating value of the produced gas by a treatment for activating the reduction reaction in a process for thermally cracking particulate organic wastes of a relatively low water content such as bark and rice hulls and utilizing the produced gases by conversion into mechanical or electric power, to utilize the tar by separation and recovery in a gas cooling step, to fully purify the obtained gas, and to enhance the value of the reaction residues and utilize them.

CONSTITUTION: A temperature sensor 11 in an exhaust gas pipe 6 connected to the top of a reaction furnace 2 automatically controls a motor 14 which regulates the amount of the feed. A residue discharge exit 3 is provided on the lower bottom of the furnace 2, and a duct 19 is arranged at the intermediate part of the furnace 2. In one example, a cooling pipe 20, a water feed pipe 22 and a suction pipe 38 are provided on suitable places of the furnace 2 and the exhaust gas pipe 6 is connected through a cooler 7 and a blower 8 to an internal combustion engine 9. In another example, a tar separator 25, a filter 26, etc., are connected, and the cooler 7 and the tar separator 25 are connected to tar storage tanks 32 and 33.