Consider upflow regeneration as demineralization alternative
This article describes how a new countercurrent upflow technique simplifies regeneration, enhances efficiency, and reduces costs. Uniform-particle-size resin augments product quality improvement, reduces waste effluent. Boiler-makeup demineralizers use separate ion-exchange-resin columns to remove cationic and anionic contaminant from raw water. Starting with fresh or completely regenerated resin, high-quality water can be produced until the resin beds are exhausted. Regenerant chemicals then passed through the beds -- acidic solution for cation-exchange resin, caustic for anion -- remove contaminant ions attached to resin-bead exchange sites by reverse ion exchange, preparing beds for reuse. Direction of regenerant flow is either the same as the service flow -- ``co-current`` or ``co-flow`` -- or in the countercurrent direction. While most US powerplants use co-current regeneration, it consumes more chemicals and involves higher cost. Countercurrent flow has the advantage of placing the most highly regenerated resin nearest the bed exit for the next cycle. This precludes early leakage of impurity ions -- usually sodium (Na+) from the cation bed, for example -- to the product stream and lengthens the service run.
- OSTI ID:
- 100679
- Journal Information:
- Power (New York), Vol. 139, Issue 7; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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