| 摘要 |
<p>PURPOSE:To provide a wet-type exhaust gas desulfurization method by which to reduce the quantity of alkali agent used for separating fluorine and metal ion dissolved in a drained liquid, when discharging a drained absorbent slurry to a drainage treatment device, in a wet-type exhaust gas desulfurization device using a calcium compound absorbent slurry. CONSTITUTION:Part of a calcium compound absorbent slurry which comes in contact with an exhaust gas containing sulfur oxide in an absorption column 2, is extracted through a pump 5, then the extracted slurry is dehydrated using a dehydrator 13 to recover gypsum 14, and part of the water drained by the dehydrator is recycled to the absorption column 2. The other part, of the water drained by the defydrator, which corresponds to the drainage amount of a desulfurization device is supplied to a neutralization tank 6 and an alkali agent 7 is added to adjust the pH value. After that, the drained water with the adjusted pH value is sent to a thickener 8 where a supernatant is discharged to a drainage treatment device. On the other hand, an underflow slurry containing a solid component is supplied to the absorption column or the dehydrator.</p> |
