Patent ID: 9403698
Filing Date: 2016-08-02
CPC Classification: B01J,C02F

Claim Text:
1. A process for purification of produced water, the process comprising: providing a closed loop cation exchange unit and a closed loop anion exchange unit, the cation exchange unit and the anion exchange unit connected in series through an intermediate degasifier, the cation exchange unit comprising a cation resin bed, the anion exchange unit comprising an anion resin bed, each of the exchange units further comprising a plurality of treatment zones, the treatment zones comprising at least an adsorption zone, a rinse zone, a regeneration zone, a pulsing zone and a backwash zone; flowing a volume of the produced water through the adsorption zone of the cation exchange unit to remove cations comprising Na+ from the produced water and produce an acidic decationized effluent; in the regeneration zone of the cation exchange unit, regenerating the cation resin bed by contacting it with an acid regenerant; in the degasifier, releasing carbon dioxide gas from the acidic decationized effluent to produce an acidic degasified effluent; producing deionized treated water having a neutral pH by flowing a volume of the acidic degasified effluent through the adsorption zone of the anion exchange unit, and in the regeneration zone of the anion exchange unit, regenerating the anion resin bed by contacting it with a caustic regenerant, wherein the regenerated anion resin bed is rinsed in a two-stage process, comprising: i) in a first stage, piping a slip stream flow of the acidic degasified effluent through the rinse zone of the anion exchange unit; and ii) in a second stage, passing a stream of the deionized treated water through the rinse zone of the anion exchange unit, wherein after the anion resin bed is regenerated, acidic degasified effluent and the deionized treated water which were used in the anion resin rinsing zone are collected and discharged through a rinse tail outlet collector as a rinse tail stream, wherein the rinse tail outlet collector is positioned within the rinse zone and above a caustic regenerant inlet distributor to prevent dilution of the caustic regenerant while rinsing the anion resin bed, wherein the rinse tail outlet collector and the caustic regenerant inlet distributor are located in a portion of the closed loop anion exchange unit where the resin moves upwardly, and wherein the rinse zone is positioned between the adsorption zone and the regeneration zone.