| abstract |
The method is implemented in a boiler (1) comprising a fluidized bed hearth (10) surmounted by an after-combustion chamber (13). The fumes cross the paths (16, 17, 19 and 21), alternately ascending and descending, where they cool in contact with walls (35, 36, 37, 38, 39) equipped with water tubes. Lime is injected (at 28) into the bed (10) to fix the sulfur oxides and halogenated compounds, and a spray of lime powder, which neutralizes, is injected (at 20), at the start of the third course (19) residues of halogenated compounds; the flying particles deposited (in 18) are recycled in the hearth (10). The temperature of the bed is maintained between 800 ° and 900 ° C, and the injection of secondary air is adjusted for an oxygen level in the fumes of between 5.5 and 7.5%, to minimize the formation of nitrogen oxides, dioxins and furans. |