초록 ▼

A method and apparatus in accordance with the invention is described which comprises treating an engine exhaust gas stream containing hydrocarbons and other pollutants. The method of this invention comprises the steps of flowing the exhaust gas stream through a catalytic member comprising a monolith

A method and apparatus in accordance with the invention is described which comprises treating an engine exhaust gas stream containing hydrocarbons and other pollutants. The method of this invention comprises the steps of flowing the exhaust gas stream through a catalytic member comprising a monolith body having a first catalyst zone and a second catalyst zone therein to contact a catalyst in a first catalyst zone to convert at least some of the pollutants in the exhaust gas stream into innocuous products. The exhaust gas stream is then discharged from the catalytic member and flowed through an adsorbent zone to adsorb at least some of the hydrocarbon pollutants with an adsorbent composition. The exhaust gas stream is then discharged from the adsorbent zone and flowed to the second catalyst zone to convert at least some of the pollutants into innocuous products. The exhaust gas stream, so treated, is then discharged to the atmosphere through suitable discharge means. A preferred adsorbent is a zeolite, having a relatively high silica to alumina ratio and a low relative Bronsted acidity. The preferred adsorbent compositions comprise Beta zeolites. An oxidant such as air may be added to the exhaust gas stream at a point upstream of the second catalyst zone.

대표청구항 ▼

[ What is claimed is:] [1.] An exhaust gas purifying apparatus for converting noxious components such as hydrocarbons and other pollutants from an engine exhaust gas into innocuous products, the apparatus comprising:a flow path for conveying engine exhaust gases containing hydrocarbons and other pol

[ What is claimed is:] [1.] An exhaust gas purifying apparatus for converting noxious components such as hydrocarbons and other pollutants from an engine exhaust gas into innocuous products, the apparatus comprising:a flow path for conveying engine exhaust gases containing hydrocarbons and other pollutants from an engine and comprising;a first catalyst zone in the flow path and downstream of the engine comprising a first catalyst effective for the conversion of at least some of the other pollutants into innocuous substances,an adsorbent zone disposed in the flow path in gas flow communication with and downstream of the first catalyst zone and comprising an adsorbent, which comprises H Beta zeolite material havina a relative Bronsted acidity of less than 0.5, for adsorbing at least some hydrocarbons in the engine exhaust gas, at least during a cold-start period of engine operation, anda second catalyst zone disposed in gas flow communication with and downstream of the adsorbent zone and comprising a second catalyst for at least converting unburned hydrocarbons into innocuous substances; andheat exchange means disposed in a heat transfer relation between the first catalyst zone and the second catalyst zone for providing heat transfer by indirect heat exchange from the first catalyst zone to the second catalyst zone.