Ion exchange regeneration plant

A regeneration apparatus for the regeneration of at least partially exhausted cation exchange material and at least partially exhausted anion exchange material, which comprises:

• a first upright enclosed regeneration vessel for effecting regeneration of exhausted cation exchange material therein;
• a second upright cylindrical enclosed regeneration vessel for effecting regeneration of exhausted anion exchange material therein;
• first vacuum aspirator means;
• first conduit means connecting a first inlet to said first vacuum aspirator means to a concentrated acid regenerant chemical storage vessel and second conduit means connecting a second inlet to said first vacuum aspirator means to a source of deionized water;
• third conduit means connecting an outlet from said first vacuum aspirator means to an inlet to said first regeneration vessel located in a top closure thereof for feeding dilute acid regenerant chemical formed by mixing said concentrated acid regenerant chemical and deionized water therein from said first vacuum aspirator means to said first regeneration vessel to effect regeneration of exhausted cation exchange material therein by flowing said dilute acid regenerant chemical downwardly through and in contact with a bed of cation exchange material supported in said first regeneration vessel;
• said first regeneration vessel including conduit means extending downwardly from an outlet in said top closure to a location adjacent the bottom thereof to receive and convey therein spent acid regenerant chemical to said outlet and screen means located at said location adjacent the bottom of the vessel for supporting said bed of cation exchange material in said first regeneration vessel for contact with acid regenerant chemical;
• said first regeneration vessel further including second inlet means located in a lower closure of the regeneration vessel below said screen means and connected to a source of calcium-free water to enable said calcium-free water to flow into the first regeneration vessel, though the screen means and through and in contact with said bed of cation exchange material to a second outlet located adjacent said top closure to effect backwashing of the exhausted cation exchange material to remove particulates therefrom prior to contact with the acid regenerant solution;
• said first regeneration vessel further including a third inlet located above said screen means and above the intended height of the cation exchange material in the bed for feeding a slurry of exhausted cation exchange material to the first regeneration vessel, a fourth inlet located in said top closure connected to a source of deionized water for feeding deionized water to said first regeneration vessel to effect washing of regenerated cation exchange material free of acidic regenerant chemical, a third outlet located in the lower closure for discharge of spent deionized water from the first regeneration vessel and a fourth outlet located adjacent the lower closure for discharge of regenerated cation exchange material from the first regeneration vessel as a slurry in the deionized water;
• second vacuum aspirator means;
• fourth conduit means connecting a first inlet to said second vacuum aspirator means to a concentrated alkaline regenerant chemical storage vessel and fifth conduit means connecting a second inlet to said second vacuum aspirator means to a source of deionized water;
• and
• sixth conduit means connecting an outlet from said second vacuum aspirator means to an inlet to said second regeneration vessel located in a top closure thereof for feeding dilute alkaline regenerant chemical solution formed by mixing said concentrated alkaline regenerant solution and deionized water therein from said second vacuum aspirator means to said second regeneration vessel to effect regeneration of exhausted anions exchange material therein by flowing said dilute alkaline regenerant chemical solution downwardly through and in contact with a bed of anion exchange material supported in said second regeneration vessel;
• said second regeneration vessel including conduit means extending downwardly from an outlet in said top closure to a location adjacent the bottom thereof to receive and convey therein spent alkaline regenerant chemical to said outlet and screen means located at said location adjacent the bottom of the vessel for supporting said bed of anion exchange material in said second regeneration vessel for contact with said alkaline regenerant chemical;
• said second regeneration vessel further including second inlet means located in a lower closure of the regeneration vessel below said screen means and connected to a source of calcium-free water to enable said calcium-free water to flow into the second regeneration vessel, through the screen means and through and in contact with said bed of anion exchange material to a second outlet adjacent said top closure to effect backwashing of the exhausted anion exchange material to remove particulates therefrom prior to contact with the alkaline regenerant solution;
• said second regeneration vessel further including a third inlet located above said screen means and above the intended height of the anion exchange material in the bed for feeding a slurry of exhausted cation exchange material to the second regeneration vessel, a fourth inlet located in said top closure connected to a source of deionized water for feeding deionized water to said second regeneration vessel to effect washing of regenerated anion exchange material free of alkaline regenerant, a third outlet located in the lower closure for discharge of spent deionized water from the second regeneration vessel and a fourth outlet located adjacent the lower closure for discharge of regenerated anion exchange material from the second regeneration vessel as a slurry in deionized water.

A process for the regeneration of at least partially exhausted cation exchange material and at least partially exhausted anion exchange material obtained from a plurality of exhausted service demineralizers employing the mixed bed principle in which each service unit is filled with a bed of exhausted anion and cation exchange materials, which comprises:

• contacting the mixed bed with sodium chloride solution to ensure that said ion-exchange material is completely exhausted;
• contacting the mixed bed with a sanitizing fluid to kill any microorganisms in said bed;
• contacting the mixed bed with hydrochloric acid to effect stripping of calcium salts from anion exchange material and organic materials from anion and cation exchange material in said mixed bed and thereby to cause said anion exchange material to be in chloride form;
• effecting substantially complete hydraulic separation of said anion exchange material from said cation exchange material while simultaneously effecting backwashing of said ion exchange material to remove particulates therefrom,
• separately feeding the hydraulically-separated at least partially exhausted cation exchange material to a first enclosed regeneration zone and the hydraulically-separated at least partially exhausted anion exchange material to a second enclosed regeneration zone physically separate from said first enclosed regeneration zone,
• subjecting said exhausted cation exchange material to backwashing in said first enclosed regeneration zone to remove particulate matter therefrom,
• subjecting said exhausted anion exchange material to backwashing in said second enclosed regeneration zone to remove particulate matter therefrom and contacting said exhausted anion exchange material in the chloride form with sodium hydroxide solution to convert said exhausted anion exchange material in chloride form to hydroxyl form,
• forming a dilute aqueous hydrochloric acid solution by mixing concentrated hydrochloric acid and substantially deionized water in a first mixing zone located externally of said first enclosed regeneration zone;
• feeding said dilute aqueous hydrochloric acid into said first enclosed regeneration zone to effect regeneration of said at least partially exhausted cation exchange material;
• recovering regenerated cation exchange material from said first enclosed regeneration zone;
• collecting partially spent aqueous hydrochloric acid solution from said first enclosed regeneration zone, passing at least part of said collected spent hydrochloric acid to said calcium and organic stripping step as the hydrochloric acid utilized therein, and forwarding the hydrochloric acid so used and any collected hydrochloric acid not so used to a neutralization zone;
• forming a dilute aqueous sodium hydroxide solution by mixing concentrated sodium hydroxide solution and substantially deionized water in a second mixing zone and located externally of said second enclosed regeneration zone;
• feeding said dilute sodium hydroxide solution into said second enclosed regeneration zone to effect regeneration of said at least partially exhausted anion exchange material to effect regeneration of said at least partially exhausted anion exchange material;
• recovering regenerated anion exchange material from said second enclosed regeneration zone;
• collecting partially spent aqueous sodium hyroxide solution from said anion exchange material regeneration, passing at least part of said collected spent sodium hydroxide to effect said chloride conversion step, and forwarding the sodium hydroxide solution so used and any collected sodium hydroxide solution not so used to said neutralization zone,
• monitoring the pH of the solution resulting in said neutralization zone from said forwarding steps, and
• adding neutralizing chemical as required to said resulting solution to effect substantial neutralization thereof for discharge.