Process of purifying flue gases

US4842835A · kind A · utility

Assignees

• Metallgesellschaft AG · DE
• Stadtwerke Munster GmbH · DE

Inventors

• Karl-Heinz Dorr
• Hugo Grimm
• Heinz Neumann · Riedstadt, DE
• Wolfgang Fennemann · Karben, DE
• Norbert Ohlms · Munster, DE

Key dates

• Filing date: Jul 17, 1987
• Grant date: Jun 27, 1989
• Expiry date: Jul 17, 2007

Classification

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

Abstract

Flue gases or other contaminated humid exhaust gases which contain SO.sub.3 are cooled by an indirect heat exchange in a heat exchanger to a temperature below the dew point temperature of sulfuric acid and are cooled further to a predetermined temperature in an SO.sub.3 condenser by means of dilute sulfuric acid, which is sprayed to flow in a countercurrent to the gas, whereby dilute sulfuric acid having a predetermined concentration is condensed. The gas leaving the SO.sub.3 condenser is scrubbed and cooled to a temperature from 40.degree. to 55.degree. C. in a fine scrubber by a treatment with a sprayed aqueous liquor. The exit gas is reheated to a predetermined temperature in a reheater by a treatment with sprayed dilute sulfuric acid from the SO.sub.3 and after the condensation of SO.sub.3 is passed through a filter. Dilute sulfuric acid from the reheater is sprayed into the SO.sub.3 condenser. The temperature of the gas in the reheater is so selected that the water which has been absorbed is not condensed but remains in the gaseous effluent. The exit temperature of the gas leaving the heat exchanger is approximately so selected that the temperature at which dilute sulfuric aci…