| 摘要 |
1481066 Removing S02 from gases; sulphates NIPPON OIL CO Ltd 30 Aug 1974 [3 Sept 1973 14 Sept 1973 5 Oct 1973] 38043/74 Heading C1A In a process for oxidizing SO 2 by contact with O 2 in presence of an aqueous solution containing at least 3 p.p.m. each of V<SP>5+</SP> and Mn<SP>2+</SP>, the catalyst is regenerated by withdrawing from the oxidation reaction at least 0À5% of the solution, adjusting its pH to 2-7 by adding Ca, Ba or Sr oxide, hydroxide and/or carbonate to precipitate the corresponding sulphate, adding H 2 O 2 or a source thereof or a gas containing O 2 <SP>-</SP> in an amount to oxidize to V<SP>5+</SP> at least 40% of the V<SP>4+</SP> in the withdrawn solution, which V<SP>4+</SP> has been formed by reduction during oxidation of SO 2 , separating the sulphate and recycling the regenerated aqueous solution to the oxidation reaction. Re Ca, Ba or Sr compound and oxidizing agent may be added together, or in either order. The source of H 2 O 2 may be a substance capable of generating H 2 O 2 upon addition to H 2 O or aqueous acid, e.g. per-compounds. Before recycle, the regenerated solution may be treated with V- and iron-containing soot to make up V and Mn adsorbed on the precipitated sulphates. The catalytic solution may also contain at least 3 p.p.m. Fe<SP>+++</SP>. In examples, SO 2 is removed from fine gas. |
