| 摘要 |
A method and an apparatus for cleaning sulphur-dioxide-containing gases, such as flue gases, are disclosed. The gases are treated in a gas scrubber (2) for the absorption of sulphur dioxide in an aqueous alkaline washing liquid (3), preferably NaOH. A partial flow (10) is drawn off from the washing liquid to be regenerated by the addition of calcium ions (17) for the precipitation and removal of calcium sulphate. The invention is distinguished by the fact that the precipitated calcium sulphate is recycled and admixed (14) with the partial flow of washing liquid before the addition of calcium ions. The apparatus comprises a gas scrubber (2) having means (5, 6, 7, 9) for circulating the washing liquid (3), a conduit (11) for drawing off a partial flow (10) of washing liquid, a vessel (16) for the addition of calcium ions (17), a vessel (18) for the sedimentation of precipitated calcium sulphate, a vessel (22) for the addition of carbonate ions, a vessel (24) for the sedimentation of calcium carbonate, a conduit (26) for recycling regenerated washing liquid to the gas scrubber (2), and a conduit (25) for recycling precipitated calcium carbonate upstream from the vessel (18) for the sedimentation of calcium sulphate. The apparatus is distinguished by a conduit (19) provided for recycling precipitated calcium sulphate and opening into a vessel (14) which is arranged upstream from the vessel (16) for the addition of calcium ions. |
