GB867469A - Improvements in or relating to method and apparatus for producing purified water from aqueous saline solutions - Google Patents

Abstract

867,469. Purifying sea water. KOPPERS CO. Inc. Sept. 1, 1959, No. 29792/59. Class 46. Ocean water enters hydrateforming vessel 1 by means of line 2 and is maintained in vessel 1 under pressure sufficient for hydrate-formation at the temperature provided by cooling jacket 3, hydrateforming gas, for example, chlorine, argon, ethylene, acetylene, methyl chloride, ethyl fluoride, methane, ethane, propane, nbutane, isobutine, or carbon dioxide, or mixtures of the same, is added under the pressure maintained in vessel 1 through line 6 by means of a distributer or sparger (not shown), and the solid hydrate formed in vessel 1 and floating in the salt solution is removed from it by means of feeder or conveyer 7 and carried into hydrate-decomposition vessel 8. On the inclined part of the feeder 7 connecting vessels 1 and 8, excess water drains to vessel 1. A liquid level in vessel 1 is maintained to permit hydrate removal by feeder 7 by means of valve 9 that controls discharge of water enriched in salts into receiver 10 maintained at atmospheric pressure. Dissolved hydrateforming gas that is released from the enriched salt solution upon depressuring in receiver 10 leaves through line 11 into compressor 12 and is recycled into vessel 1. Make-up hydrateforming gas can be added, if necessary through line 13 or 14. Solid hydrate preferably washed is discharged into the hydrate-decomposing vessel 8 and is decomposed by heat supplied from heating jacket 15. Gas liberated from the hydrate leaves vessel 8 through conduit 18 and is recycled by means of pump 19 and line 6 into vessel 1. The hydrate-forming gas can return from vessel 8 to the vapour space of vessel 1 without use of recycle pump through the housing of the conveyer connecting these two vessels. In this case, the hydrate-forming gas is absorbed at the surface of the solution contained in vessel 1 or by water sprayed into vessel 1. Purified water in vessel 8 is depressured by means of valve 20 into receiver 21. Dissolved hydrate-forming gas which is liberated by the pressure decrease leaves through line 11. Purified water is discharged through line 22 and may be freed of dissolved hydrate-forming gas in an aerating tower (not shown), or by vacuum treatment. Enriched salt water leaves receiver 10 by means of conduit 23 and can be freed of residual dissolved gas similarly. The hydrate may be decomposed by pressure decrease alone as described in the embodiment of Fig. 2 (not shown).