Method for reducing the nitrogen oxide concentration in gases

US7744839B2 · kind B2 · utility

Assignee

• UHDE GMBH · DE

Inventors

• Meinhard Schwefer · Meschede, DE
• Rolf Siefert · Rheda-Wiedenbrück, DE
• Michael Groves · Gevelsberg, DE

Key dates

• Filing date: Apr 27, 2006
• Grant date: Jun 29, 2010
• Expiry date: Jul 20, 2026

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02C20/10
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The method comprises passing an N2O- and NOx-containing gas over a sequence of two catalyst beds, adding reducing agents for NOx and for N2O between the catalyst beds in such an amount that not only NOx but also a predetermined proportion of N2O is reduced. The reaction conditions are set so that the N2O content of the gas is reduced by not more than 95%, based on the N2O content at the entrance of the first catalyst bed, by decomposition to nitrogen and oxygen in the first catalyst bed and that not only chemical reduction of NOx but also chemical reduction of N2O occurs in the second catalyst bed so that the N2O content of the gas is reduced by at least 50%, based on the N2O content at the entrance of the second catalyst bed.