Stratification of mixed-bed resin with reversed resin layers
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Our company’s mixed-bed resin reactor has recently experienced a leak in the middle section, which caused some of the resin to leak out. Now, when the layers separate, the anion and cation resins have switched places – the anion resin is at the bottom while the cation resin is on top. What could be the reason for this?
It should be impossible; if the washing is done correctly and for long enough, this problem won’t occur. The most serious issue is merely that the anionic and cationic resins stick together and cannot be separated; I’ve actually never encountered a situation where the anionic resin is on the bottom and the cationic resin on top. It is unreliable to judge male and female resins solely based on color.
After the backwashing is complete, drain the water quickly; the cationic and anionic resins will settle naturally, forming a distinct separation interface. If the resins clump together, introduce a small amount of alkali into the resins in the bed before they separate. After regeneration, the resin layers on the anion and cation sides may become contaminated, resulting in color variations, which is a normal phenomenon.