Ion exchange columns are also known as mixed beds. The so-called ion exchange column is to mix and load a certain proportion of cation and anion exchange resins in the same exchange device to exchange and remove ions in the fluid.
Classification of ion exchange columns (mixed beds): Mixed beds can be divided into three types based on regeneration methods: in vivo regeneration mixed beds, in vitro regeneration mixed beds, and anion resin external migration regeneration mixed beds.
1. Extracorporeal regeneration mixed bed is suitable for enterprises with low flow rates and strict environmental requirements. However, due to the large number of supporting equipment and complex operation of the extracorporeal regeneration mixed bed, it is now rarely used.
2. Internal regeneration mixed bed and anion resin external transfer regeneration mixed bed are suitable for high flow, specialized water treatment operators, and wastewater treatment scenarios. The internal regeneration mixed bed operates and the entire regeneration process is carried out inside the mixed bed. During regeneration, the resin does not move out of the equipment, and both the cation and anion resins are regenerated simultaneously. Therefore, fewer auxiliary equipment are required and the operation is simple.
3. External migration regeneration mixed bed of anion resin: The basic structure of the anion resin external migration regeneration mixed bed and its supporting anion resin regeneration column is roughly the same as that of a small counter current regeneration fixed bed. The thickness of the anion resin regeneration column is smaller than that of the mixed bed, and the required expansion height is 50% to 60% of the resin layer height. Therefore, the regeneration column can be lower, but generally made the same as the mixed bed for uniformity.