Method and system for the purification of exhaust gas from an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9561468-B2
Application number	US-201214391926-A
Country	US
Kind code	B2
Filing date	Apr 27, 2012
Priority date	Apr 27, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The invention provides a method and system for the purification of exhaust gas from an internal combustion engine, comprising a filter and a SCR catalyst. The filter is periodically regenerated increasing the temperature of the exhaust gas up to 850° C. and the water vapor content up to 100% by volume. The SCR catalyst comprises a hydrothermally microporous stable zeolite and/or zeotype having the AEI type framework and being promoted with copper.

First claim

The invention claimed is:

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 3 -SCR;
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.

2. The method of claim 1 , wherein the atomic copper to aluminium ratio is between about 0.01 and about 1 for the zeolite and the atomic copper to silicon ratio is between 0.01 and about 1 for the zeotype.

3. The method of claim 1 , wherein the atomic ratio of silicon to aluminium is between 5 and 50 for the zeolite and between 0.02 and 0.5 for the zeotype.

4. The method of claim 1 , wherein 80% of the initial reduction of nitrogen oxides at 250° C. is maintained after the catalyst has been exposed to a temperature of 750° C.

5. The method of claim 1 , wherein at least 80 to 90% of the initial microporosity is maintained after aging at 600° C., and at least 30 to 40% is maintained after aging at 750° C.

6. The method of claim 3 , wherein the catalyst is an aluminosilicate zeolite SSZ-39 and/or silicoaluminum phosphate SAPO-18.

Assignees

• Marin Manuel Moliner
• Marti Cristina Franch
• Gimeno Antonio Eduardo Palomares
• Canós Avelino Corma
• Vennestrøm Peter N R
• Grill Marie
• Kustov Arkady
• Thøgersen Joakim Reimer
• Haldor Topsoe As

Inventors

• Marin Manuel Moliner
• Marti Cristina Franch
• Gimeno Antonio Eduardo Palomares
• Canós Avelino Corma
• Vennestrøm Peter N R
• Grill Marie
• Kustov Arkady
• Thøgersen Joakim Reimer

Classifications

• B01D53/9418 Primary

  for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas · CPC title

• B01D2255/915

  Catalyst supported on particulate filters · CPC title

• B01D2257/404

  Nitrogen oxides other than dinitrogen oxide · CPC title

• F01N13/001

  Exhaust gas flow channels or chambers being at least partly formed in the structural parts of the engine or machine (using structural parts of the vehicle B60K13/06) · CPC title

• B01D2255/20761

  Copper · CPC title