Process for purifying an aqueous methyldiethanolamine solution

US5607594A · kind A · utility

Assignee

• Krupp Koppers GmbH · DE

Inventors

• Werner Pohl · Neubulach, DE
• Johannes Menzel · Oberhausen, DE

Key dates

• Filing date: Sep 5, 1995
• Grant date: Mar 4, 1997
• Expiry date: Sep 5, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S423/14
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In the process for purifying an aqueous MDEA-solution the formate content of the MDEA-solution circulated in a main stream between the absorber and desorber of a hydrogen sulfide wash unit for gas produced by gasification of a carbonaceous material, e.g. coal, is measured. A partial stream of MDEA-solution is withdrawn from the main stream, passed over an ion exchange medium which removes some formate present to form a partially purified partial stream and subsequently the purified partial stream is returned to the main stream. The amount of the withdrawal from the main stream is controlled so that the formate content of the main stream is maintained between 10 and 30 g/l. Only from 0.5 to 0.08% by volume need be withdrawn from the main stream to form the partial stream. The ion exchange medium can be regenerated with a hydroxide-containing solution, which is subsequently fed to an ammonia separator column of a hydrogen sulfide wash apparatus.