PURPOSE: To enhance the sealing performance and to prevent the splashing and back flow of fine powder by placing the space part which is present between the fine powder-charging part in the kneader and the charging port of a conveyer in the cylindrical body provided by the partition plate acting as a screw-type vane.

CONSTITUTION: The dewatered sludge 16 carried by a dewatered sludge conveyer 13 passes through a dewatered sludge-charging port 4 and is put into the kneader 1. The dewatered sludge 16 is pushed out by a paddle-type vane 31a and a screw-type vane 9, and said sludge 16 is sent toward the outlet side by the paddle-type vane 31b while being mixed with the pulverized coal and the desulfurizing agent-fine powder introduced from a fine powder charging port 5. Meanwhile, the phenomenon of the back flow of high-temperature air to the kneader 1 side occurs by the pulsation of the internal pressure of an incinerator, however a certain degree of sealing effect is displayed by a quantitative feeding machine 7 and the rubber-made pending seal 3 (gas back flow-preventing member) provided at several parts in the kneader 1.