| 摘要 |
The present invention relates to a flue-gas desulfurization system in which a discharge-gas heat recovery device 2 has been disposed in a discharge-gas passage that precedes a desulfurization device 1, wherein wastewater from heat recovery device 2 cleaning is neutralized with a large excess of limestone in a limestone slurry tank 7, and Al matter dissolved away from the coal ash contained in the wastewater from cleaning is solidified. Since the limestone slurry contains no fluorine matter, the limestone is not masked even when the wastewater from heat recovery device 2 cleaning is supplied to the limestone slurry tank 7. Furthermore, since the wastewater from heat recovery device 2 cleaning has been neutralized in the limestone slurry tank 7, no local decrease in pH occurs in the absorption liquid even when the limestone slurry within the tank 7 is supplied to the desulfurization device 1. Hence, the Al matter in the desulfurization/absorption liquid can be inhibited from reacting with fluorine matter. Consequently, in the present invention, the wastewater from gas-cooler cleaning can be treated in a desulfurization device with a minimum equipment configuration at low cost without lowering the reactivity of the limestone, thereby enabling the desulfurization device to be continuously operated. |
