Abstract: A method for removing organic foulants such as organic sulfonates from an anion exchange resin comprises treating the anion exchange resin at an elevated temperature with a defouling solution containing at least 6% ammonium sulfate (wt/wt sulfate). The method is useful for removing organic foulants from the anion exchange resin used for polishing condensate water in power plants.

Abstract: Water is demineralized by passage through a water demineralization system. The water demineralization system comprises a series of at least three ion exchange resin zones. The sequential series comprises a strong acid cation (SAC) resin zone, a first anion resin zone, and a weak acid cation (WAC) resin zone. The SAC resin zone comprises a SAC resin for removing cations from the water, the first anion resin zone comprises an anion resin for removing anions from the water, and the WAC resin zone comprises a WAC resin for removing cations from water without substantially splitting any salts present in the water. Means for connecting each resin zone in the series are provided so that water can pass sequentially through the system. A method is also provided for regenerating the WAC resin from sodium and ammonium exhaustants. This method comprises contacting the WAC resin with an aqueous solution of a regenerant that is substantially devoid of sulfur and halogen groups.

Abstract: Water is demineralized by passage through a water demineralization system. The water demineralization system comprises a series of at least three ion exchange resin zones. The sequential series comprises a strong acid cation (SAC) resin zone, a first anion resin zone, and a weak acid cation (WAC) resin zone. The SAC resin zone comprises a SAC resin for removing cations from the water, the first anion resin zone comprises an anion resin for removing anions from the water, and the WAC resin zone comprises a WAC resin for removing cations from water without substantially splitting any salts present in the water. Means for connecting each resin zone in the series are provided so that water can pass sequentially through the system. A method is also provided for regenerating the WAC resin from sodium and ammonium exhaustants. This method comprises contacting the WAC resin with an aqueous solution of a regenerant that is substantially devoid of sulfur and halogen groups.

Abstract: A process for regenerating the anion and cation exchange resins used for polishing water for steam generation allows the polishers to be operated with reduced effluent levels of sodium, chloride and sulfate to prevent corrosion of the steam turbine power plant system. In the process, both the cation and anion exchange resins are treated only with neutral or alkaline aqueous solutions including ammonium sulfate.