Patent ID: 6428760
Filing Date: 2002-08-06
Classification: B01D

Abstract:
A method for desulfurizing an exhaust gas in a system comprising: (i) a desulfurization tank, (ii) an oxidization tank, (iii) a double decomposition tank, and (iv) a magnesium hydroxide recovery tank, said method comprising:(a) desulfurizing an exhaust gas in the desulfurization tank; (b) oxidizing a liquid drawn from the desulfurization tank in an oxidation tank; (c) subjecting a liquid drawn from the oxidization tank to double decomposition reaction; (d) storing magnesium hydroxide and gypsum formed in the double decomposition tank in the magnesium hydroxide recovery tank; (e) supplying a slurry from the magnesium hydroxide recovery tank to the desulfurization tank and/or the oxidization tank; (f) discharging accumulated impurities as blow water from the system, said blow water containing magnesium; (g) adding a magnesium compound and water at a mixing ratio to one of (I) the desulfurization tank, (II) the oxidization tank, or (III) the magnesium hydroxide recovery tank; and (h) adjusting the mixing ratio in accordance with the molar concentration of magnesium in the blow water.