| 摘要 |
PROBLEM TO BE SOLVED: To provide an economical and practical method and apparatus for seawater desulfurization with less environmental load, enabling equipment costs and running costs to be greatly reduced.SOLUTION: A method for desulfurizing sulfurous acid gas-containing exhaust gas comprises: a sulfurous acid gas absorption step in which seawater is introduced into an exhaust gas desulfurizing tower, gas-liquid contact is made between the seawater and the sulfurous acid gas-containing exhaust gas, the sulfurous acid gas in the exhaust gas is absorbed into the seawater, and after seawater absorption, the exhaust gas is led out of the exhaust gas desulfurizing tower; a first decarbonation step of decarbonizing the seawater that has absorbed the sulfurous acid gas; an oxidation step of oxidizing bisulfite ions in the seawater after the first decarbonation step; and a mixing step of mixing seawater that has not been used for desulfurization with the seawater that has absorbed the sulfurous acid gas, prior to the oxidation step. The pH of the seawater from after the sulfurous acid gas absorption step to before the mixing step is 2.2≤pH≤4.0, and in the mixing step, the mixture ratio of the seawater that has not been used for desulfurization and the seawater that has absorbed the sulfurous acid gas is adjusted on the basis of the pH of the seawater from after the sulfurous acid gas absorption step to before the mixing step. |
