Patent GB-1392208-A (GB)
Title: Enrichment systems
IPC: B01D59/32
Filed: 1972-03-22
Abstract: 1392208 Fluid phase enrichment systems DEUTERIUM CORP 22 March 1972 [22 March 1971] 13480/72 Heading C1A A fluid phase containing a first material concentrated therein is formed by exchanging, at different temperatures, said first material with a second material between chemically different first and second fluid phases which are physically separable from each other and which are each capable of containing each of said materials; the method is of the type in which: said second fluid phase is passed through each of second and first units, in that order, of a pair of exchange units; said first fluid phase is caused to flow in countercurrent contact with said second fluid phase in each of said first and second units in said pair; said first and second units are maintained at different temperatures to cause said second fluid phase to become progressively enriched in said first material in said second unit, and to become progressively impoverished in said first material in said first unit of said pair, and said first fluid phase to become progressively enriched in said first material in said first unit, and to become successively impoverished in said first material in said second unit of said pair; and enriched fluid passing between said units is withdrawn. The method particularly comprises increasing, in a part of said second unit, the proportionate amount of first fluid phase in contact with the second fluid phase after said second fluid phase has reached an increased level of enrichment of said first material therein, while decreasing, in a part of said first unit, the proportionate amount of first fluid phase in contact with the second fluid phase after said second fluid phase has reached an increased level of impoverishment of said first material therein. In a specified embodiment of the process, the first material is deuterium, the first fluid is water, the second fluid is another compound of hydrogen physically separable from water (preferably a gas partially soluble in water, and most preferably hydrogen sulphide), and the deuterium-enriched water withdrawn from one pair of exchange units is fed to a second pair of exchange units, so as to produce a more highly enriched water containing up to 99À8 mol percent deuterium as deuterium oxide. Apparatus suitable for the process of the invention comprises : first and second direct contact exchange units forming a pair; means connected to said exchange units for passing said second fluid phase through each of said second and first exchange units, in that order, of said pair; means connected to said exchange units for causing said first fluid phase to flow in countercurrent contact with said second fluid phase in each of said first and second units of each pair; means for maintaining said first and second units at different temperatures so as to cause the progressive enrichment and impoverishment of said first material in said fluid phases described above; and means connected to said units for withdrawing from the apparatus enriched fluid passing between the units. The apparatus further comprises means for varying the proportionate amount of said first fluid phase in contact with said second fluid phase in said first and second units as described above. The variation in the proportionate amount of said first fluid phase in contact with said second fluid phase in said first and second units is preferably effected by withdrawing from part of said second unit a portion of the first fluid phase in contact with the second fluid phase therein, and adding to part of said first unit a further quantity of first fluid phase of substantially the same concentration of said first material as the portion of said first fluid phase withdrawn from said second unit. In a preferred embodiment, the means for withdrawing said first fluid phase from said second unit and the means for adding said first fluid phase to said first unit are connected, so that the portion of said first fluid phase which is withdrawn from said second unit is added to said first unit.