Process for the purification of exhaust gases

US5122358A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gunter Lailach · Krefeld, DE
• Rudolf Gerken · Krefeld, DE

Key dates

• Filing date: Nov 23, 1988
• Grant date: Jun 16, 1992
• Expiry date: Nov 23, 2008

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B17/74
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A process for the purification of hot exhaust gases containing dust, sulphur dioxide and/or hydrogen chloride and/or hydrogen fluoride and having a water vapor partial pressure of at least 15 volume %, wherein PA0 a) the hot exhaust gases are cooled to temperatures below 135.degree. C. by scrubbing with 60-75% sulphuric acid, PA0 b) the exhaust gases from a) are cooled to 60.degree.-80.degree. C. by contact with 5-20% sulphuric acid, PA0 c) the exhaust gases from b) are desulphurized in contact with moist active charcoal to form sulphuric acid, PA0 d) the sulphuric acid formed in c) is raised to a concentration of 5 to 20% H.sub.2 SO.sub.4 in contact with the hot exhaust gases, PA0 e) the 5 to 20% sulphuric acid formed in d) is evaporated to a concentration of 60 to 80% H.sub.2 SO.sub.4 by the heat obtained from cooling the exhaust gases of a) and PA0 f) prior to stage e) HCl and/or HF is removed from a mixture of 5 to 20% H.sub.2 SO.sub.4 from d) with 60 to 80% sulphuric acid.