Patent ID: 9561468
Date: 2017-02-07
CPC Classifications: B01D,B01J,F01N,Y02T

Claim:
1. Method for the purification of exhaust gas from an internal combustion engine, comprising reducing the content of soot in the exhaust gas by passing the gas through a filter; subsequently reducing the content of nitrogen oxides in presence of ammonia or a precursor thereof in contact with a catalyst being active in NH periodically regenerating the filter by burning of soot captured in the filter and thereby increasing temperature of the exhaust gas up to 850° C. and water vapour content up to 100% by volume; and passing the exhaust gas from the filter through the catalyst during the regeneration of the filter, wherein the catalyst comprises a hydrothermally microporous stable zeolite and/or zeotype having the AEI type framework and being promoted with copper, and maintains 80% of the initial reduction of nitrogen oxides at 250° C. after the catalyst has been exposed to a water vapour content of 100% in the exhaust gas for 13 hours.