Method for obtaining ammonia from waste water containing NH3 and acid gases

US6558452B1 · kind B1 · utility

Assignee

• MG Technologies LLC · DE

Inventors

• Hans-Martin Stonner · Eschborn, DE
• Gert Ungar · Frankfurt am Main, DE
• Matthias Linicus · Champigny-sur-Marne, FR

Key dates

• Filing date: May 30, 2001
• Grant date: May 6, 2003
• Expiry date: May 30, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S210/903
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Ammonia is recovered from waste water containing NH3, at least one acid gas (CO2, H2S) and inert gases. Firstly, the waste water is passed through a pretreatment column and then, at least in part, into a total stripping column. The top product from the total stripping column is cooled in a condenser, and an aqueous NH3-containing condensate coming from the condenser is fed to an NH3 stripping column. The top product from the NH3 stripping column is brought into direct contact with circulating aqueous NH3-containing condensate in a wash column, and NH3 is recovered from the top product from the wash column. Some of the bottom product from the wash column is fed back into the NH3 stripping column. The temperature in the bottom region of the pretreatment column is set to from less than 30 to 200° C., a sub-stream of the waste water is introduced into the upper region of the pretreatment column, and a second sub-stream of the waste water is fed into the pretreatment column below the first sub-stream. At least 80% of the NH3 introduced from the total stripping column is condensed in the condenser. A waste-water stream is taken off from the total stripping column, at least part there…