| 摘要 |
PURPOSE:To produce fly ash of excellent quality, by a method wherein coal ash, collected by a dust collector, is introduced to a classifying device to classify it into coarse powder and fine powder, a part of the fine powder is circulated and charged to a combustion furnace for coal togetherwith high temperature combustion exhaust gas or a preheated air to burn it, and the remaining fine powder is removed as a product out of a system. CONSTITUTION:A high temperature electric dust collector 2a, an air preheater 5, a gas.gas heater 6, a desulfurizing device 7 and a chimney 8 are connected to the exhaust duct of a combustion boiler 1 for pulverized coal. After coal ash, collected by a dust collector, is stowed in an ash disposing part 10 once, it is introduced to a classifying device 3 to classify it into coarse powder and fine powder. A part of the fine powder, classified by the classifying device 3, is charged into a preheating air line 11, an exhaust gas circulating line 12, or an exhaust gas mixing line 13 to return it to a combustion furnace for pulverized furnace for combustion, and the remaining fine powder is removed as on-specification ash fly out of a system. |
