Process and apparatus for concentrating a solution

US4981555A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Klaus Hohmann · Hofheim, DE
• Manfred Mai · Frankfurt am Main, DE

Key dates

• Filing date: Sep 21, 1989
• Grant date: Jan 1, 1991
• Expiry date: Sep 21, 2009

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S159/901
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The solutions are concentrated by multiple-effect evaporation in indirectly heated evaporators. The highest concentration of the solution is reached in a final evaporator stage, which is heated with live steam. The final evaporators stage includes two to four falling-film evaporators, all of which are heated with live steam. The falling-film evaporators are consecutively flown through by the solution. Vapor is withdrawn from that falling-film evaporator which is the first to be supplied with the solution and at least part of said vapor is directly contacted with the solution as it flows down through the heating zone of at least one other evaporator of the final stage. From that falling-film evaporator of the final stage which is the first to be supplied with the solution the vapor may be fed to all other evaporators of the final stage.