| 摘要 |
An input water stream containing a water-soluble sulfite compound is treated to produce elemental sulfur, while minimizing the formation of undesired sulfate by-products by the steps of: (a) selectively converting the sulfite compound to the corresponding thiosulfate compound; (b) reacting a portion of the resulting thiosulfate-containing stream with a reducing agent to form a sulfide-containing stream; (c) reacting the remaining portion of the thiosulfate-containing stream with the sulfide-containing stream to form the corresponding polysulfide compound; and thereafter, subjecting the resulting stream containing the polysulfide compound to decomposition conditions selected to form elemental sulfur, hydrogen sulfide, and a substantially sulfate-free treated water stream. The principal utility of this treatment procedure is associated with the clean up, or regeneration, of sulfite-containing aqueous streams such as are produced by contacting SO2 -containing flue gas with a suitable aqueous absorbent stream. Key features of this process are the selective conversion of the sulfite compound to the corresponding thiosulfate compound, the subsequent reduction of a portion of this thiosulfate compound to the corresponding sulfide compound and the use of this sulfide compound to selectively reduce the remaining portion of the thiosulfate compound to elemental sulfur.
|
