Patent GB-1264987-A (GB)
IPC: B01J47/10
Filed: 1969-04-08
Abstract: 1,264,987. Ion exchange. CHEMICAL SEPARATIONS CORP. 8 April, 1969 [8 April, 1968], No. 17801/69. Heading B1J. Contaminant is removed from liquid by contacting the liquid with solid material contained in a column loop, such removal being effected by a process which comprises the steps of (a) passing the liquid containing the contaminant downwardly through solid material contained in a first section of the column loop, whereby contaminant is transferred from the liquid to the solid material, and passing a regenerating agent for the solid material upwardly through solid material contained in a second section of the column loop, whereby contaminant is transferred from the solid material to the regenerating agent thereby to regenerate the solid material, (b) interrupting the passage of the liquid through the first section and of the regenerating agent through the second section and (c) moving solid material in the column loop from one section thereof to another contiguous section thereof by passing solid material regenerated in the second section from the lower portion of the second section and into the lower portion of the first section and by passing solid material which carries contaminant removed from the liquid from the upper portion of the first section and into the upper portion of the second section, steps (a), (b) and (c) being repeated as desired. Step (a) may be carried out for a first predetermined period of time and step (b) may be carried out for a second predetermined period of time. The process may be effected in apparatus which comprises a column loop 10 having a contaminant loading section 12 for removing contaminant from the liquid, a contaminant stripping section 14 for regenerating the solid material, a rinsing section 34 for rinsing regenerated solid material, a reservoir 48 for solid material, a pulsing section 52 for effecting movement of the solid material around the loop, valves 36 and 46 for isolating the contaminant loading section from the remainder of the loop and valves 54 and 56 for isolating the pulsing section from the remainder of the loop, the two legs of the loop being interconnected by an upper end section 20 and a lower end section 32. Liquid which contains contaminant enters the contaminant loading section via line 16, valve 24 and distributor 26, liquid which contains a reduced amount of contaminant leaving the contaminant loading section via collector 28, line 18 and valve 30. Regenerating agent enters the contaminant stripping section via line 44 and valve 42, regenerating agent which contains contaminant leaving the contaminant stripping section via line 22 and valve 64. Rinse liquid for regenerated solid material enters the rinsing section via line 38 which may contain a valve (not shown) actuated by servo mechanism, for example a solenoid valve (not shown), controlled by conductivity probe 40 whereby the interface between the regenerating agent and the rinse liquid is constrained to remain at a predetermined level. During step (a), isolating valves 36, 46 and 56 are closed and isolating valve 54 is open; during step (c), isolating valves 36, 46 and 56 are open and isolating valve 54 initially is closed, the solid material being caused to move around the loop by introduction of liquid into the pulsing section via line 58 and valve 60, excess liquid leaving the loop via overflow 50 from the reservoir and solid material displaced from the contaminant loading section being stored in the reservoir until isolating valve 54 is opened, prior to commencement of the subsequent step (a), to allow such solid material to pass into the now empty pulsing section. The solid material may be backwashed in the pulsing section by liquid entering the pulsing section via line 62.  The process may be used to demineralize or deionize water, to reduce the alkalinity of water, to remove phosphates from water, to remove plating wastes from liquid and to remove colour, odour and organic material from liquid; the solid material may be alumina, activated carbon or ion-exchange material, for example a strong acid cation exchange resin, a weak acid cation exchange resin, a strong base anion exchange resin, a weak base anion exchange resin or a mixture thereof; dependent upon the nature of the solid material, the regenerating agent may be an alcohol, an acid, a base or a water-soluble salt, for example sodium chloride. The process is exemplified with reference to the softening of water by means of ion exchange resin; details are given of suitable type, particle size and amount of resin, type and amount of regenerating agent, flow rates of the feed water and pulse water, flow rate of the resin within the loop during pulsing movement thereof, hardness characteristics of the feed water and product water, and dimensions of the apparatus.