What about my softeners?

Water pretreatment for boilers operating below 1,000 psig (6.89 MPA) requires removal of scale-producing cations (calcium and magnesium) from filtered water. The common term for calcium and magnesium ions in water is ?hardness.?

The most common boiler pretreatment technology in refineries and chemical plants is sodium zeolite softening due to the relatively low cost and tolerance for changes in influent water quality. Synthetic zeolites, also known as cation exchange resin (Fig. 1) reversibly exchanges hardness for sodium or hydrogen ions.

The cation resin shown in Fig. 1 is a conventional resin; there is a Gaussian distribution of bead diameters. Resin suppliers now offer uniform particle size resin with higher regeneration efficiencies and a greater physical strength. The dark discoloration of some of the resin beads shows that dissolved iron in the influent water exchanged onto...


Huchler, L. A.

May 01, 2004

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