Abstract:
Method for the preparation of a wall flow particulate filter catalysed at its inlet side with a first catalyst having activity in the removal of residual hydrocarbons and carbon monoxide and catalysing at rich burn engine operation conditions the reaction of nitrogen oxides with hydrogen and/or carbon monoxide to ammonia and catalysed at its outlet side with a second catalyst having activity in the selective reduction of NOx by reaction with ammonia being formed in the inlet side. The method involves the provision of a first catalyst having a particle size larger than the filter wall mean pore size, and a second catalyst having a particle size smaller than the filter wall mean pore size, and mixing the first and second catalyst into one suspension, which is used for washcoating from the inlet end. The second catalyst thereby diffuses into the partition wall.
Abstract:
Method for the preparation of a wall flow particulate filter catalysed at its inlet side with a first catalyst having activity in the removal of residual hydrocarbons and carbon monoxide and catalysing at rich burn engine operation conditions the reaction of nitrogen oxides with hydrogen and/or carbon monoxide to ammonia and catalysed at its outlet side with a second catalyst having activity in the selective reduction of NOx by reaction with ammonia being formed in the inlet side. The method involves the provision of a first catalyst having a particle size smaller than the filter wall mean pore size, and a second catalyst having a particle size larger than the filter wall mean pore size, and mixing the first and second catalyst into one suspension, which is used for washcoating from the outlet end. The first catalyst thereby diffuses into the partition wall.
Abstract:
Wall flow particulate filter catalysed at its inlet side with a catalyst having activity in the removal of residual hydrocarbons and carbon monoxide and catalysing at rich burn engine operation conditions the reaction of nitrogen oxides with hydrogen and/or carbon monoxide to ammonia and catalysed at its outlet side with a catalyst having activity in the selective reduction of NOx by reaction with ammonia being formed in the inlet side.
Abstract:
Method and system for the removal of noxious compounds from exhaust gas of a lean burning internal compression ignition engine, the method comprising passing the exhaust gas through a particulate filter being catalysed with a first SCR catalyst for selective reduction of nitrogen oxides; wherein aqueous ammonium nitrate is injected into the exhaust gas upstream the catalysed particulate filter during a cold start phase of the engine when the gas has a temperature of below 250°C, and wherein - when the exhaust gas has reached a temperature of about 220-250°C - injection of ammonium nitrate is discontinued and urea is injected into the gas, either upstream the first SCR catalyst or downstream the first SCR catalyst and upstream a second SCR catalyst for the selective reduction of nitrogen oxides.
Abstract:
The invention provides a method for purification of exhaust gas from a diesel engine in a system, which comprises a device for selective catalytic reduction and a diesel particulate filter preferably at least partially covered by a catalytic layer installed downstream of the device for selective catalytic reduction. A device for catalytic oxidation is installed upstream of the device for selective catalytic reduction and/or between the device for selective catalytic reduction and the diesel particulate filter. A device for injection of a controlled amount of reductant is installed inlet of the device for selective catalytic reduction, and a device for injection of a controlled amount of hydrocarbon is installed inlet of the catalytic oxidation.
Abstract:
The invention pertains to a catalysed particulate filter provided in its entire dispersion side and within its partition walls with a first catalyst being active in selective catalytic reduction of nitrogen oxides, and in its entire permeate side with a second catalyst combination with a catalyst being active in oxidation of ammonia mixed with a catalyst being active in oxidation of carbon monoxide and hydrocarbons and a method for its preparation. The mean particle size of the first catalyst is smaller than the mean pore diameter of the longitudinal porous walls, and the mean particle size of the second catalyst combination is larger than the mean pore diameter of the longitudinal walls. In the example, the first catalyst is a silica aluminium phosphate SAPO-34 promoted with 2% copper and the second catalyst is a mixture of platinum and palladium (molar ratio 3:1) supported on alumina particles and beta zeolite powder with 1.0% copper.
Abstract:
The invention provides a process for purification of an exhaust gas comprising nitrogen oxides, carbon monoxide, hydrocarbons and particulate matters from an internal combustion engine comprising the step of contacting the exhaust gas with one or more catalysts on one or more cross corrugated wire mesh sheets (5) being arranged between two or more gas impermeable cross corrugated sheets (4). The exhaust gas is contacted with one or more catalysts being coated in different zones on the one or more cross corrugated wire mesh sheets (5). Particulate matters in the exhaust gas are retained in a zone of the gas impermeable sheets (4), where the zone is porous and optionally coated with an oxidation catalyst. The exhaust gas from the combustion engine can be heated by the purified exhaust gas. The invention further comprises an apparatus for the purification process of an exhaust gas from an internal combustion engine.
Abstract:
Method and system for the removal of noxious compounds from lean burning engines, the method comprising in series the steps of contacting the exhaust gas with a catalyst being active in oxidation of volatile organic compounds and carbon monoxide, passing the treated exhaust gas through a particulate filter catalysed with a first SCR catalyst, and passing the exhaust gas leaving the particulate filter through a second SCR catalyst, wherein ammonia is injected into the exhaust upstream of the catalysed particulate filter at a temperature below or at about 220°C and wherein urea is injected into the exhaust gas between the first and the second SCR catalyst when the exhaust gas has reached a temperature of about 200°C.
Abstract:
Method for the preparation of a catalysed particulate fil- ter and a particulate filter. The method comprises the steps of a) providing a catalyst wash coat with a first catalyst ac- tive in burning off of soot and a second catalyst active in selective catalytic reduction of nitrogen oxides; b) coating a particulate filter body with the catalyst wash coat on the dispersion side and the permeate side of the filter body and within partition walls of the filter body; and c) drying and heat treating the coated filter body to ob- tain the catalysed particulate filter.