| 摘要 |
<p>PURPOSE:To obtain a high desulfurization rate in a single absorbing tower and to directly recover high purity gypsum from an absorbing liquid slurry, by specifying a liquid-gas ratio, a liquid staying time and the pH of the absorbing liquid slurry in the absorbing tower. CONSTITUTION:Exhaust gas 1 containing 1,000ppm or less of SO2 and 4% or more of O2 is introduced into an absorbing tower 2 and SO2 is removed by a basic Ca-compound slurry to discharge the treated gas to the atmosphere. In this case, the liquid-gas ratio in the absorbing tower 2 is set to 13l/m<2> or more and the liquid stay time therein is set to 13hr or more. The pH of the absorbing liquid slurry is adjusted to 4-6 by regulating the flow amount of the absorbent from an absorbent preparing apparatus 6. A part of the absorbing liquid slurry is sent to a gypsum separating apparatus 13 from a flowline 9 through a concn. apparatus 10 separate gypsum.</p> |
