GB902347A - Improvements relating to the ion-exchange treatment of water - Google Patents

Abstract

902,347. Ion-exchange. PERMUTIT CO. Ltd. April 14, 1960 [April 20, 1959], No. 13416/59. Class 46. When water is being treated for the removal of dissolved salts, it enters the vessel 2 through a pipe 7 and leaves through the device 6. When regeneration is required the mixed bed, and the top layer 3 of cation-exchange material, is washed by upward flow of water from a pipe 13, this water flowing to waste through a pipe 14. The valves 8 and 11 are then shut and the materials are allowed to stratify into layers 15 and 16 as shown in Fig. 2, all the cationexchange material forming the bottom layer 16. Next a volume of material equal to that of the layer 3 is moved into a vessel 21, which acts as a measuring vessel; valves 17 and 18 are opened and water flows under pressure through the opened valve 17 into the vessel, and carries with it enough material to form a bed 22, (not shown), in vessel 21. The valves 17 and 18 are then shut again; the layers 15 and 16 move downwards and regeneration of the materials now takes place in the usual way, an alkali being introduced from a source 25 and passing out through the device 5. When the layer 15 has been regenerated the valve 8 is shut, the valve 10 is opened to connect the pipe 9 to a pipe 27, and the valve 11 is set to connect a source 47 of acid or brine to the pipe 12. The acid flows downwards through the layer 16 in the vessel 2 and then through the pipe 27 to the device 28 in the vessel 21, and thence through the material that has been moved into this vessel. The effluent acid regenerant flows to waste through the device 23 and pipe 24. At the end of this step the valve 11 is set to allow water to flow from a pipe 48 through the layer 16 in the vessel 2 and then through the material in the vessel 21 to rinse away excess regenerant. Next the valves 11 and 10 and a valve 29 in the pipe 24 are shut, and the layers 15, 16 are formed into a fresh mixed bed 1 by the upward flow of compressed air introduced through the valve 10 and device 6 and escaping through the pipe 34. Then the valve 18 is set to connect a pipe 30 to the vessel 21, while a valve 31 in a pipe 32 at the bottom of the vessel is opened. Water under pressure flows through the pipe 30 into the vessel 21 and carries the cationexchange material 22 through the pipe 32 back to the vessel 2 to form a new layer 3. The process may also be modified in that the device 5 may be at a higher point in the main vessel 2, that is to say at the level of the top of the cation-exchange layer. In such a case there is no regeneration outside the vessel 1 at all, and the bottom layer of regenerated cationexchange material is moved from the vessel 2, to the vessel 21 only to allow remixing to take place and is immediately thereafter returned to the vessel 2 to form the top layer 3. The vessel 21 therefore needs no device 28. A process in which the regeneration takes place outside the vessel in which the water is treated is also described. A second vessel of substantially the same size as the vessel 2 is provided instead of the vessel 21.