Method and device for reducing the number of particles in an exhaust gas

US6941742B1 · kind B1 · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Ronald Neufert · Aichach, DE
• Frank Witzel · Saratoga Springs, US
• Stefan Fischer · Lichtenfels, DE
• Gunther Pajonk · Zapfendorf, DE

Key dates

• Filing date: May 10, 2000
• Grant date: Sep 13, 2005
• Expiry date: May 10, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

To reduce the number of particles in an exhaust gas (A), in particular in the exhaust gas (A) from an internal-combustion engine, sulfur dioxide SO2 which is contained in the exhaust gas (A) is at least partially catalytically oxidized, in the presence of ammonia NH3 in a catalytic converter system having a catalytic activity which increases in the direction of flow, to form sulfur trioxide SO3. The simultaneous presence of sulfur trioxide SO3 and ammonia NH3 in the exhaust-gas stream which is brought about in this way results in an agglomeration of the small and very small particles and reduction in the number thereof.