To understand the behavior of the entrained-flow gasification of organic wastes, high calorie value polypropylene (PP) and low calorie value polyethylene terephthalate (PET) were gasified in a single nozzle type Drop Tube Furnace (DTF). In a small scale of gasifier, it is very difficult to obtain as high temperature as 1, 300°C with a low oxygen-carbon molar ratio as being done in larger scale than pilot plants, and it is necessary to operate in high oxygen-carbon molar ratio in order to maintain the reaction temperature 1, 300°C because the heat loss becomes significant in comparison with heating load in the furnace. When methane gas was introduced as an auxiliary fuel under the low oxygen-carbon molar ratio, the reaction temperatures was achieved over 1, 300°C and higher carbon gasification conversion than 80% was attained. The composition of the main gas produced by gasification was correlated by the shift reaction equilibrium at the temperature above 1, 250°C. Then the equilibrium constant, which was almost independent of the temperature in the range, could be approximated about 0.85.
