METHOD AND APPARATUS FOR HEAT TREATMENT USING DOWNWARDLY SWIRLING HOT GAS FLOW

摘要

This invention relates to and discloses a novel apparatus for the heat treatment of a bed of material. The apparatus includes an upright cylindrical furnace with an inlet for the bed-forming material and a gas outlet at the top. It comprises a plurality of gas nozzles above the bed which are oriented at a downward angle a between the axis of each nozzle and a horizontal sectional plane through the furnace defined by 0.degree.< a ? 30.degree., and at a skew angle .beta. between the axis of each nozzle and a horizontal line tangent to the furnace circumference at the point where the nozzle axis intersects the furnace wall defined by 45.degree. ? .beta. ? 85.degree.. Gas streams introduced through the nozzles produce a downwardly swirling flow having a truncated conical configuration to confine the bed material. This apparatus allows both the steps of heat treatment and separation and recovery to be accomplished for minute solid particles within the same apparatus in a compact and efficient system. The apparatus is suitable for soots and sludges which have remained untreated in the prior art, asbestos, industrial sludge, wastes and like material.