Method for removal of ammonia from a gas mixture

US5230877A · kind A · utility

Assignee

• NORSK HYDRO ASA · NO

Inventors

• Dag Arne Eimer · Porsgrunn, NO
• Lars E. Oi · Porsgrunn, NO

Key dates

• Filing date: Jun 27, 1991
• Grant date: Jul 27, 1993
• Expiry date: Jun 27, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/52
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention relates to a method of catalytic production of ammonia, where a gas mixture consisting mainly of unconverted synthesis gas, some ammonia, inert gases and possibly also water is recirculated to the synthesis reactor being first freed from the main part of the ammonia and possibly also water by absorption. The gas mixture is brought in contact with a hygroscopic abosrption agent having two or more OH-groups for absorption of ammonia and possibly also water. The absorption is carried out at a pressure being substantially the same as the ammonia synthesis pressure, and ammonia being desorbed from the absorption agent at a lower pressure and higher temperature than at the absorption. At least part of the possibly present water is removed from the absorption agent before it is supplied to the absorption column. Preferably it si applied ethylene glycol, diethylene glycol or triethylene glycol alone or in mixture as absorption agent. Possible water can be removed form the absorption agent by inert stripping gas before it is returned to the absorption column.