| 摘要 |
PURPOSE:To efficiently remove an ammonium compound and black coal ash in coal ash respectively to utilize the same effectively by heating coal ash collected from an exhaust gas of a coal boiler in a dust collecting apparatus to a specific temp. CONSTITUTION:An exhaust gas from a coal boiler 1 is successively passed through a denitration apparatus 2, an air preheater 3, a dust collecting apparatus 4, a heat exchanger 5 and a desulfurization apparatus 6 to be treated. Coal ash from which dust is removed in the dust collecting apparatus 4 contains black coal ash and an ammonium compound. Said coal ash is thrown into an ammonium compound pyrolysis furnace 11 and subjected to solid-gas contact at 300-500 deg.C to decompose said ammonium compound and a decomposed gas containing ammonia is separated in a solid-gas separator 13 to be utilized in the denitration apparatus 2. Further, separated coal ash is thrown into a classifier 14 to be classified into a fine powder and a crude powder containing black coal ash such as uncombusted carbon or the like. The crude powder is thrown into a decoloring furnace 15 to be baked at 500- 1,100 deg.C and, after decoloring, transported to an ash treating installation through an ash cooler 16. |
