Abstract: A high temperature air heater including a heat transfer conduit located in higher temperature gas. The heat transfer conduit is made up of a heat transfer pipe through which the air to be heated flows and a refractory protective pipe covering the heat transfer pipe. A clearance is provided between the heat transfer pipe and the refractory protective pipe. The clearance makes it possible to accommodate the differences in thermal expansion between the heat transfer pipe and the refractory protective pipe to prevent damaging the refractory protective pipe, thus extending the service life of the high temperature air heater.

Abstract: In an air heater for use in recovering, by heat exchange, the heat of an exhaust gas generated from an incinerator for disposing of wastes, prolonged service life and improved working efficiency are attainable with least thermal deformation. The air heater has a heat transfer conduit which is placed in high temperature highly corrosive gas.

Abstract: In an apparatus for heating high-temperature air for use in recovering, by heat exchange, the heat of an exhaust gas of elevated temperature generated from an apparatus for disposing of wastes, prolonged service life, improved working efficiency, improved efficiency of heat recovery on heat exchange are attainable with least thermal deformation and reduced dust deposition.

Abstract: A fluidized bed combustion method for burning wastes using a fluidized bed furnace is not affected by a fluctuation in the quantity and quality of wastes fed into the furnace, if any, thereby preventing CO gas, etc. from discharging out of the furnace. The furnace has a number of air-diffusing tubes for feeding primary air to the fluidized bed in parallel with each other at the bottom of the fluidized bed, and a free space part formed above the fluidized bed for burning unburnt matter with a secondary air. Each air-diffusing tube has a number of nozzles provided along the axis of the tube and a primary air control device including an open-close damper for controlling the quantity of air to be fed through the tube. The primary air is fed into the fluidized bed through the air-diffusing tubes one after another according to a predetermined open-close pattern by the primary air control device so that the ratio of the air quantity Uo to the minimum fluidizing air quantity Umf (Uo/Umf) is in the range of 1.

Abstract: Incineration flyash is treated by reducing the organic chlorine compounds contained in the flyash. A cylindrical body equipped with a rotating shaft having a screw conveyor and agitating blades for conveying and agitating the flyash is filled to at least a 75 vol % charge so that contact of the flyash with oxygen is made as small as possible. The flyash is subjected to agitation and heat-treatment at 300.degree. C. or higher. The cylindrical body has a feeding port for the waste incineration flyash and a discharging port for the discharge of the treated flyash. The screw conveyor is at the introducing part and has a pitch that is successively reduced toward the agitating part for charging the flyash in the agitating part at a greater vol. % than that which occurs in the introducing part.