Method and apparatus for producing ammonia (NH3)

US6928807B2 · kind B2 · utility

Assignee

• MAN Nutzfahrzeuge AG · DE

Inventors

• Eberhard Jacob · Krailling, DE
• Sebastian Käfer · Kirchheimbolanden, DE
• Werner C. Muller · Harsewinkel, DE
• Andreas Lacroix · Weidenthal, DE
• Andreas Herr · Wolfsburg, DE

Key dates

• Filing date: Feb 14, 2003
• Grant date: Aug 16, 2005
• Expiry date: Feb 14, 2023

Classification

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

Abstract

A method is provided for producing ammonia (NH3) and introducing the produced ammonia (NH3) into an exhaust gas stream as a reduction means for selectively catalytically reducing nitrogen oxides contained in the exhaust gas stream, which is an exhaust stream generated by the combustion process of a motor, a gas turbine, or a burner. The method comprises feeding dry urea from a supply container in a controlled amount to reactor and subjecting the dry urea in the reactor to a sufficiently rapid thermal treatment such that a gas mixture comprising the reaction products of ammonia (NH3) and isocyanic acid (HCNO) is created. Also, the method comprises immediately catalytically treating the thus produced gas mixture in the presence of water such that the isocyanic acid (HCNO) resulting from the rapid thermal treatment is converted, via quantitative hydrolysis treatment, into ammonia (NH3) and carbon dioxide (CO2).