Process and catalyst for reducing nitrogen oxides

A process for reducing the nitrogen oxides present in a lean exhaust gas from an internal combustion engine by selective catalytic reduction on a reduction catalyst using ammonia, wherein a fraction of the nitrogen monoxide present in the exhaust gas is oxidized to nitrogen dioxide before the exhaus...

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Bibliographic Details
Main Authors PFEIFER MARCUS, SPURK PAUL, SCHAEFER-SINDLINGER ADOLF, KREUZER THOMAS, DEMEL YVONNE, LOX EGBERT
Format Patent
LanguageEnglish
Published 18.01.2005
Edition7
Subjects
BLASTING
CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY
CHEMISTRY
COMPOUNDS THEREOF
ENGINE PLANTS IN GENERAL
GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES
GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL
HEATING
INORGANIC CHEMISTRY
LIGHTING
MACHINES OR ENGINES IN GENERAL
MECHANICAL ENGINEERING
METALLURGY
NON-METALLIC ELEMENTS
PERFORMING OPERATIONS
PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
SEPARATION
STEAM ENGINES
THEIR RELEVANT APPARATUS
TRANSPORTING
WEAPONS
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Summary:A process for reducing the nitrogen oxides present in a lean exhaust gas from an internal combustion engine by selective catalytic reduction on a reduction catalyst using ammonia, wherein a fraction of the nitrogen monoxide present in the exhaust gas is oxidized to nitrogen dioxide before the exhaust gas, together with ammonia, is passed over the reduction catalyst. The reduction catalyst contains a zeolite exchanged with transition metals and oxidation of the nitrogen monoxide is performed in such a way that the exhaust gas contains 30 to 70 vol. % of nitrogen dioxide before contact with the reduction catalyst.
Bibliography:Application Number: US20010838119