METHOD AND APPARATUS FOR TREATING WASTE MATERIAL

摘要

Method and apparatus for treating waste material in a counter flow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in countercurrent direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone. According to one aspect of the invention the secondary exhaust gases are passed in heat exchange relationship with respect to the air being added to the furnace.