Process for desulphurizing flue gases

US4670235A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gunter Lailach · Krefeld, DE
• Rudolf Gerken · Krefeld, DE
• Karl-Heinz Schultz · Krefeld, DE

Key dates

• Filing date: Sep 12, 1985
• Grant date: Jun 2, 1987
• Expiry date: Sep 12, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B17/775
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In the desulphurizing of SO.sub.2 - and hydrogen halide-containing flue gases by catalytically oxidizing the sulphur dioxide on moist active carbon at a temperature of from 45.degree. to 70.degree. C. with the formation of 3 to 20% dilute sulphuric acid, the improvement which comprises contacting the dilute sulphuric acid with the hot flue gases to be desulphurized so as to evaporate water resulting sulphuric acid of a concentration of from 60 to 85%, and removing by evaporation the hydrogen chloride and hydrogen fluoride dissolved in the dilute sulphuric acid. Advantageously evaporation is carried out in two scrubbing stages, the hydrogen chloride and hydrogen fluoride being removed, by vacuum evaporation or by stripping with air or flue gas, from a mixture of the dilute sulphuric acid from the second scrubbing stage with the concentrated sulphuric acid from the first scrubbing stage, the mixture having the H.sub.2 SO.sub.4 concentration of from 40 to 70%.