| 摘要 |
<p>1324809 Purifying gas streams CIT COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS 9 Dec 1970 [9 Dec 1969] 58522/70 Heading B1R [Also in Division C1] Exhaust gas containing particles and oxides of sulphur and nitrogen is passed from burner 1 to and through column 2 cocurrent with wash liquor introduced at 3, and thence to and through column 6 countercurrent with wash liquor at 35-45‹C introduced at 7, before being vented to the atmosphere. The packing material 4 in columns 2, 6 is suitably chips of polyamide. The wash liquor used in both columns is supplied by pumps 14, 15 from bath 10 in which is contained finely divided iron or ferrous or ferric carbonate or oxide. In the case of gas containing oxides of sulphur, ferrous sulphate forms in the wash liquor and is returned from bath 9 to bath 10 while entrained particles are run off from bath 9. Part of the ferrous sulphate which is formed is eliminated in bath 12 by blowing air and possibly also a catalyst into the liquor at 16; ferric sulphate collects at 17 and is run off while solution is returned by pump 13 to bath 12. The ferric sulphate may thereafter be hydrolysed to sulphuric acid and ferric oxide, which latter may be returned to bath 10. Alternatively, excess ferrous sulphate in the liquor in bath 10 may be removed by cooling the liquor to below 30‹C and removing the crystallised salt which forms. If preferred, the liquor supplied to columns 2, 6 may be taken from bath 12 instead of bath 10, in which case the line returning liquor from bath 12 to bath 10 is unnecessary. Oxides ofnitrogen are removed in an analogous manner.</p> |
