Abstract: Method for the preparation of a monolithic catalyst for the reduction of nitrogen oxides VOC and carbon monoxide in an off-gas, the catalyst comprises at least one platinum group metal, vanadium oxide, titania and optionally tungsten oxide.
Type:
Application
Filed:
June 19, 2017
Publication date:
May 16, 2019
Applicant:
Haldor Tøpsoe A/S
Inventors:
Kim Hougaard Pedersen, Viggo Lucassen Hansen, Francesco Castellino
Abstract: A method for the cleaning of exhaust gas from a compression ignition engine, comprising the steps of injecting a first amount of an aqueous urea solution into the gas; in a first mode of operation and at an exhaust gas temperature of between 150 and 220° C. hydrolysing the first amount of urea to ammonia reducing agent in presence of a first catalyst comprising vanadium oxide supported on titania and subsequently removing part of nitrogen oxides contained in the exhaust gas by contacting the gas mixed with the ammonia reducing agent through a second catalyst comprising platinum on titania and/or alumina; and in a second mode of operation and at an exhaust gas temperature above 220° C. removing a part of the nitrogen oxides in presence of the first catalyst and the ammonia reducing agent and subsequently oxidising hydrocarbons, carbon monoxide and remaining amount of the ammonia reducing agent further contained in the exhaust gas by passing the gas through the second catalyst.