Process of removing pollutants from exhaust gases

US4670237A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Rolf Graf · Königstein, DE
• Lothar Reh · Zumikon, CH
• Michael Schroter · Remscheid, DE

Key dates

• Filing date: Feb 26, 1986
• Grant date: Jun 2, 1987
• Expiry date: Feb 26, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D53/501
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In a process of removing pollutants consisting substantially of sulfur oxides from exhaust gases at temperatures below 150.degree. C. by means of a sorbent which contains calcium carbonate, calcium oxide and/or calcium hydroxide and which is included in a circulating fluidized bed system consisting of a fluidized bed reactor, a separator and a return line, a complete utilization of the sorbent is achieved in that a partial stream of laden sorbent is withdrawn from the circulating fluidized bed and is subjected at a temperature of 600.degree. to 1200.degree. C. to an oxidizing treatment, a major part of the sorbent that has been subjected to an oxidizing treatment is recycled to the circulating fluidized bed, and a partial stream which contains the sorbent mainly in the form of calcium sulfate is removed from the process. Fresh sorbent is supplied to the circulating fluidized bed and/or to the stage for the oxidizing treatment at the rate at which said partial stream is removed from the process.