Furnace for the selective incineration or carbonization of waste

Abstract

A furnace for the selective incineration or carbonization, by a process of distillation to remove its volatile components, of waste materials, the furnace consisting of an elongated, slightly inclined, rotatable cylindrical kiln, waste material being introduced into its upper end, moved along the length thereof in the form of a tumbling bed at its lower portion by rotation thereof either at higher rates to produce higher turbulence of the material as is useful in the incineration mode of operation, or at lower rates for less turbulence of the material as is useful in the carbonization mode. Air is introduced into the kiln either in large amounts supplying ample oxygen for full combustion as is useful in the incineration mode, or in sub-stoichiometric amounts as is necessary in the carbonization mode. The air is introduced into longitudinally successive zones of the kiln in independently regulated amounts to coincide with the amounts of combustible gas produced in each zone in the carbonization mode, and is circulated in a longitudinal vortex pattern, either in alternately opposite directions in successive zones to supply air-gas turbulence useful in the incineration mode, or in the same direction in all zones as required in the carbonization mode. An afterburner receiving effluent from the kiln is supplied with large amounts of turbulent air for burning the combustible components of the effluent, but has a zone of greatly reduced turbulence allowing solid particulate matter to drop from the effluent by gravity.