US 4,904,383 A · System for demineralizing water

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. The regenerant is selected from the group consisting of (a) organic acids, (b) inorganic acids, (c) amine salts of (a) and (b), (d) amines, and (e) combinations thereof.

Claims34

Dependent claims

A system for use in demineralizing source water for subsequent use in a water-using apparatus, the system comprising (a) a series of at least three ion exchange resin beds arranged in sequential order comprising (i) a strong acid cation resin bed comprising a strong acid cation resin for removing cations from the source water passing therethrough to yield a first effluent, (ii) a first anion resin bed comprising an anion resin for removing anions from the first effluent passing therethrough to yield a second effluent, and (iii) a weak acid cation resin bed comprising a weak acid cation resin for removing cations from the second effluent passing therethrough without substantially splitting any salts present in the second effluent to yield a third effluent, (b) means for introducing the source water into the strong acid cation resin bed, (c) means for passing the first effluent from the strong acid cation resin bed to the first anion resin bed, (d) means for passing the second effluent from the first anion resin bed to the weak acid cation resin bed, and (e) means for delivering the third effluent from the weak acid cation resin bed to the apparatus without passing the third effluent through any additional ion exchange resin beds.

A system for polishing water comprising the following arranged in sequential order:

(a) a strong acid cation resin bed comprising a strong acid cation resin for removing cations from water passing through the strong cation resin bed to yield a first effluent;
(b) a first anion resin bed comprising a strong base anion resin for removing anions from water of the first effluent passing through the first anion resin bed to yield a second effluent;
(c) a weak acid cation resin comprising a weak acid cation resin for removing cations from water of the second effluent passing through the weak acid cation resin bed without substantially splitting any salts present in the water to yield a third effluent,
the first anion resin bed being between the strong acid cation resin bed and the weak acid cation resin bed;
(d) means for passing the first effluent to the first anion resin bed;
and
(e) means for passing the second effluent to the weak acid cation resin bed.

4 more elements

Dependencies are inferred from the claim text.

System for demineralizing water

Life of this patent

System for demineralizing water

Life of this patent

Abstract

Claims34