| 摘要 |
<p>1493980 Treating exhaust gas MITSUBISHI JUKOGYO KK 16 April 1975 [19 April 1974] 15726/75 Heading C1A Exhaust gas is treated to remove oxides of nitrogen and of sulphur by washing with a lime or limestone slurry containing alkali metal iodide or alkaline earth metal iodide. It is desirable that the exhaust gas is subjected to a pre-cooling to 90‹ C. or less and a pre-oxidizing step, preferably using ozone, hydrogen peroxide or nitric acid, to convert nitrogen monoxide to dioxide before the washing step. After washing, the excess lime may be converted to calcium sulphate (in the form of gypsum) by adding sulphuric acid, and keeping the pH below 6, and the resultant calcium sulphite is then oxidized to Ca sulphate with a free-oxygen containing gas. The solid components may be separated from the slurry by filtration or centrifuge and the separated liquor containing the iodide may be recycled.</p> |
