EXHAUST GAS TREATMENT APPARATUS AND METHOD

摘要

Apparatus and method for filtering combustible particles from an exhaust gas stream, and for periodically rejuvenating the filter bed (19) and catalyst portion (32) thereof, by incinerating retained particles. A portion of an exhaust gas stream is heated (36) upstream of the filter so as to raise the catalyst to a temperature above the temperature at which the catalyst can initiate combustion of said particles. A small amount of a supplementary fuel is injected (52) into the exhaust gas stream prior to the latter entering the catalyst section, thereby causing the heated fuel/gas mixture to ignite. Subsequent to initiation of the oxidation reaction, further preheating energy input can be discontinued without affecting the combustible particle incineration rate. The supplementary fuel is preferably brought into heat exchange contact with the filter to heat the fuel prior to its injection into the exhaust gas stream. A controlled rate of carbon removal from the exhaust gas stream can thus be achieved without damage to the filter by thermal shock.