Rectisol

When Rectisolverfahren is a physical gas purification process (especially for systems following ) gas components such as carbon dioxide, hydrogen sulfide, and also HCN, COS or ammonia by means of the washing medium to be removed from the crude gas produced unwanted methanol. The Rectisolverfahren was independently developed in the mid 20th century by the company Linde and Lurgi. Patents and trademarks are used in common.

Process

The Rectisolverfahren is usually from 3 to 4 process steps, namely from the absorption of hydrogen sulphide, COS and HCN, the absorption of carbon dioxide, the desorption of carbon dioxide ( coarse regeneration) and desorption of the remaining adsorbed gas components in the heat regeneration. The absorption is carried out under pressure of 30 to 60 bar and at about -40 ° C.

• Absorption of hydrogen sulfide ( COS also, HCN and ammonia ): With the help of easy -laden carbon dioxide and cold methanol, these Gaskomponnenten away in a high scrubbing tower from the raw gas by absorption.
• Absorption of carbon dioxide: With the help of easy -laden carbon dioxide and regenerated, cold methanol is removed in a high carbon dioxide scrubbing tower from the raw gas by absorption.
• Desorption of carbon dioxide: the carbon dioxide is separated from the laden methanol over several stages mainly by expansion and stripping gases again. Due to the desorption of carbon dioxide to methanol is further cooled. The carbon dioxide is relatively pure and can be used in other chemical processes.
• Root Regeneration: The gases dissolved in the methanol as hydrogen sulfide, COS, HCN, and ammonia, and residual carbon dioxide are removed by heating in a distillation column again. The hydrogen sulphide-containing exhaust gas must be treated in a subsequent Claus plant.

The heat generated in the absorption must be compensated by the use of a refrigeration plant, for example. The purified crude gas can be used for example as a synthesis gas in other chemical processes.