Patent FR-2893260-A1 (FR)
Title: Device for production of ammonia as reducing agent for the selective catalytic reduction of nitrogen oxides in the exhaust gas of motor vehicle, comprises a nitrogen oxide-production unit, a hydrogen-production unit and a storage catalyst
Inventor: BREUER NORBERT
IPC: B01D53/56
Filed: 2006-11-13
Abstract: A device for production of ammonia as reducing agent for the selective catalytic reduction (SCR) of nitrogen oxides in the exhaust gas of motor vehicle, comprises a nitrogen oxide-production unit (10) and a hydrogen-production unit (11), which are separated by a combustion source and its exhaust gas system, and storage catalyst or nitrogen storage. The ammonia in direction of flow before the SCR-catalyst (26) is mixed with the exhaust gas. The nitrogen oxide storage and the storage catalyst are combined to form a construction unit. A device for production of ammonia as reducing agent for the selective catalytic reduction (SCR) of nitrogen oxides in the exhaust gas of motor vehicle, comprises a nitrogen oxide-production unit (10) and a hydrogen-production unit (11), which are separated by a combustion source and its exhaust gas system, and storage catalyst or nitrogen storage. The ammonia in direction of flow before the SCR-catalyst (26) is mixed with the exhaust gas. The nitrogen oxide storage and the storage catalyst are combined to form a construction unit. A fuel and/or an air/fuel mixture and/or a fuel-air-exhaust gas-mixture or air and/or exhaust gas are supplied to the nitrogen oxide production unit and to the hydrogen-production unit. The hydrogen and the nitrogen oxide production unit are combined for alternating the production of hydrogen and nitrogen oxide. Two storage catalysts (17.1, 17.2) are intended for the storage of nitrogen oxide and for the formation of ammonia. Both the production units are carried out as separate units, are connected alternately with the storage catalysts over reversible gas way (16) and are implemented as a plasma reactor. A fuel-air-mixture with a lambda of 0.33-0.66 is supplied to the hydrogen production unit, which is carried out as thermal evaporator for the fuel with a downstream reformation catalyst. An electrode of the plasma reactor is carried out as thermal evaporator for the fuel, as hollow electrode, in which the fuel is supplied. A counter flow heat exchanger for transmission of heat energy emerging from a product gas from the reformation catalyst or emerging from a gas flow from the plasma reactor, is intended on the thermal evaporator to supply educt gas from air and fuel. During the thermal evaporation of the fuel, the plasma reactor is switched on and the fuel and/or an air/fuel mixture and/or a fuel air exhaust mixture are supplied to an area in direction of flow after the plasma zone. Air guiding webs are arranged in an air supply in direction of flow before the thermal evaporator for the fuel and/or before the reformation catalyst. The SCR-catalyst is formed as ammonia storage. An independent claim is included for a procedure for the production of ammonia as reducing agent for the selective catalytic reduction (SCR) of nitrogen oxides in the exhaust gas of motor vehicle.