Process and device for reducing pollutants, especially nitrogen oxides in combustion exhaust gases

US6132693A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Werner Gruenwald · Gerlingen, DE
• Klaus Dieterich · Stuttgart, DE
• Steffen Franke · Schwieberdingen, DE

Key dates

• Filing date: Oct 6, 1997
• Grant date: Oct 17, 2000
• Expiry date: Oct 6, 2017

Classification

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

Abstract

A process for reducing pollutants, particularly nitrogen oxides from combustion gases during a combustion process that takes place while oxygen is supplied, includes providing oxygen needed for the combustion process by separating oxygen from a gas mixture containing oxygen and nitrogen in a two-step process including (a) enriching the gas mixture with oxygen in a first step to provide an enriched gas mixture; and (b) separating oxygen out of the enriched gas mixture in a second step, wherein, during at least one step oxygen depleted gas mixture is removed via an outlet provided with permeability means that cause the outlet to have a higher permeability for nitrogen than oxygen. A device for carrying out this process includes a device for separating oxygen out of a gas mixture containing oxygen and nitrogen including a housing having an inlet for the gas mixture; an outlet for the oxygen separated out of the gas mixture; and first and second apparatuses which have a respectively different permeability for oxygen and nitrogen, and which divide the device into first, second, and third chambers, wherein at least the second chamber is connected to an outlet provided with a permeability…