GB1283523A - Process of and apparatus for the ion-exchange treatment of liquids - Google Patents

Abstract

1283523 Ion exchange; softening/demineralising water PERMUTIT CO Ltd 13 Aug 1969 [22 Aug 1968 17 March 1969] 40239/68 and 13926/69 Heading B1J An ion exchange process wherein ion exchange material in an absorber is traversed by liquid, whereby exchange of ions takes place between the ion exchange material and. the liquid, and intermittently is removed from the absorber at the liquid inlet end thereof, is moved through a closed circuit which includes a regenerator in which ions taken up by the ion exchange material when in the absorber are removed by regenerant and, after such regeneration and subsequent rinsing in either the regenerator or a separate rinser to remove excess regenerant and products of regeneration, is returned through the closed circuit to the absorber at the liquid outlet end thereof is characterized in that, at each such intermittent movement of ion exchange material, a quantity of ion exchange material occupying a space in the absorber defined by a transverse device through which the ion exchange material can pass and by one end of the absorber is passed from the absorber to the regenerator, ion exchange material in the absorber is moved towards and into the space vacated by ion exchange material, a quantity of ion exchange material occupying a space in the regenerator (or rinser, if separate from the regenerator) defined by a transverse device through which the ion exchange material can pass and by one end of the regenerator (or rinser) is passed from the regenerator (or rinser) to the absorber and ion exchange material in the regenerator (or rinser) is moved towards and into the space vacated by ion exchange material, the defined space in the absorber being such as to hold the same quantity of ion exchange material as the defined space in the regenerator (or rinser) and provision of treated liquid by flow of liquid through the absorber being maintained during movement from the absorber of ion exchange material occupying the defined space therein. As exemplified, the process is effected in plant comprising an absorber and a regenerator in which regenerated ion exchange material is rinsed, the flow of liquid being either upward in both the absorber and the regenerator, see Figures 1 to 5 (not shown), or downward in both the absorber and the regenarator, see Figures 6 to 8 (not shown), or upward in the absorber and downward in the regenerator, see Figure 9 (not shown), or downward in the absorber and upward in the regenerator, see Figure 10 (not shown); in such plant, the transverse device defining the space in each of the absorber and regenerator may be a liquid distributing system occupying at least 60 per cent of the cross-sectional area of the absorber or regenerator. The rate of flow into the absorber of liquid to be treated may be increased during movement of ion exchange material from the defined space in the absorber in order to maintain the rate of flow of treated liquid during such movement. Liquid to be treated may be passed through regenerated ion exchange material in the regenerator during movement of ion exchange material into the defined space in the absorber in order to provide treated liquid during such movement which, when flow of liquid is upward in the absorber, may be effected or accelerated by introducing, into the top of the absorber, liquid under pressure, for example treated liquid delivered from the regenerator. The process may be used to soften water or to demineralize water in a plant comprising an absorber and regenerator employing cation exchange material and an absorber and regenerator employing anion exchange material; reference also is made to the use of the process in the recovery of uranium.