Filtration of crud by powdered ion exchange resin

The filtration mechanism of powdered ion exchange resin, which is used in BWR power plants, was studied through filtration experiments of two type resins. A filtration model was proposed to calculate the increase in pressure drop of a powdered resin layer by crud filtration. According to observations of the sectional appearance of the powdered resin layer, crud was adsorbed in it, and this amount decreased exponentially with increased depth. This meant that filtration in powdered resin could be evaluated by a conventional model for deep bed filtration. But this model includes no consideration of contraction of the powdered resin layer, because it was developed for a deep bed without contraction. Therefore, the effect of contraction was measured by basic compaction experiments, and a new model was proposed to evaluate this effect by modification of the conventional one. The new model provided calculation results which agreed within 5% of the experimental ones. (author)