Purification of waste gases by combustion - at widely varying rates and concentrations without backward flame propagation risk

摘要

Methods of, and appts. for purifying by decomposition at 800-1000 degrees C., waste gases contg. organic or mineral substances, in which the flow of gas varies between wide limits is claimed. The concn. of O2 and of combustible substances varies so that the explosive limit is sometimes exceeded; supplementary combustible is added to maintain the decomposition temp. According to the invention, air or waste gas which contains no combustible substances, is added to the waste gases, the flow regime is made laminar and the gas mixt. is sent to the combustion chamber, with no boundary layer on the wall of the inlet duct. The quantity or combustible-free waste gas is added in a constant proportion which maintains the rate at a value defined on a curve determined experimentally, between 3 and 20% of the max. flow rate of the waste gases. The invention ensures direct combustion of flammable waste gases in a burner which prevents propagation of a backward flame and reduced explosion risk, to a greater extent than is possible with existing methods, and without incurring the high capital and running costs associated with existing methods.