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1. (WO2001032296) METHOD AND APPARATUS FOR BINDING POLLUTANTS IN FLUE GAS

Pub. No.:    WO/2001/032296    International Application No.:    PCT/FI2000/000948
Publication Date: Fri May 11 01:59:59 CEST 2001 International Filing Date: Thu Nov 02 00:59:59 CET 2000
IPC: B01D 53/34
B01D 53/50
F23C 10/10
F23J 7/00
F23J 15/02
Applicants: FOSTER WHEELER ENERGIA OY
Inventors: KUIVALAINEN, Reijo
TSUO, York
Title: METHOD AND APPARATUS FOR BINDING POLLUTANTS IN FLUE GAS
Abstract:
A method of and an apparatus for binding pollutants in flue gas in one or more combustion plants, one of the one or more combustion plants comprising a furnace, a flue gas channel connected to the furnace, a contact reactor provided in the flue gas channel, a dust separator provided in the flue gas channel after the contact reactor, an ash recirculation conduit connecting the dust separator and the contact reactor, the recirculation conduit having a moistening device arranged therein, and a retention tank for ash arranged below the contact reactor. The method includes, among other features, maintaining reactions resulting in the production of flue gas containing pollutants in the furnace, causing flue gas to flow through the flue gas channel to the dust separator, where the ash containing unreacted calcium oxide is separated from the flue gas, conducting a portion of the separated ash to the moistening device, where water amounting up to 50% of the weight of the ash is mixed into the ash, mixing moistened ash into the flue gas flowing in the contact reactor, whereby ash is entrained with the flue gas to the dust separator thus binding pollutants in the flue gas, causing a portion of the moistened ash, which is mixed into the flue gas, to fall down into the retention tank for ash, hydrating at least a portion of the calcium oxide in the ash to form calcium hydroxide in the retention tank and recycling at least a portion of the ash from the retention tank to at least one of the one or more combustion plants.