The softening resin needs to be regenerated after the internal ions are exhausted, but most users are not familiar
with regeneration, which shortens the service life of the resin and affects its use. The regeneration method of
softening resin is usually divided into co-current regeneration, counter flow regeneration and parallel flow.
Co-current regeneration: Co-current regeneration refers to the cleaning and soaking process of the regeneration
liquid after reverse flushing and configuration. It is called co-current regeneration because the cleaning and soak-
ing process is carried out in the direction of the water flow during operation. It is usually carried out from top to
bottom.
Countercurrent regeneration: Countercurrent regeneration refers to the regeneration liquid flowing in the oppo-
site direction of operation, and the regeneration liquid flows upward. It is also called reverse regeneration. It can
effectively improve the regeneration degree and improve the quality of the produced water.
Parallel flow regeneration: Parallel flow regeneration refers to the regeneration liquid entering from the top and
bottom of the exchanger at the same time and being discharged from the drainage device in the resin layer. It is
equivalent to the upper half using countercurrent regeneration and the lower half using reverse regeneration.
Regeneration process of softening resin:
Backwashing: When the ion exchange capacity of the softening resin is exhausted, after prolonged use, the surf-
ace of the resin contains a large amount of impurities. Before regeneration, it is necessary to remove the impuri-
ties adsorbed on the surface so that the resin can have better contact with the regeneration liquid. Backwashing
is usually performed from the bottom inlet and top outlet, with a backwash flow rate of 5-10 m/h. The backwa-
shing time is about 10-15 minutes.
Brine absorption: After the water is drained, open the acid inlet valve and the upper outlet valve, and inject the
regeneration solution prepared into the system (softening resin is usually regenerated with HCL solution). After
the acid liquid level exceeds 500px above the resin, open the lower outlet, and clean the resin with the regener-
ation solution. The flow rate is controlled at 600-1000 L/h, and the cleaning time is about 40 minutes. If necess-
ary, you can soak for a while.
Slow rinsing: Clean the resin with clean water at a flow rate of 600-1000 L/h to remove the residual regeneration
solution on the surface and prevent pollution of the produced water. The usual slow rinsing time is 30 minutes.
Fast rinsing: Usually, to completely remove the regeneration solution and other impurities on the surface of the
resin, it is necessary to rinse with clean water using the working flow rate. The outlet water should be qualified
soft water. The usual fast rinsing process is 5-15 minutes.
Regeneration precautions: 1. When preparing the regeneration solution, use clean water for mixing, and do not
use tap water to prevent hardness ions and particles from being carried into the resin. 2. When the softening resin
is contaminated by impurities, it can be regenerated with twice the regenerant to effectively solve the problem of
resin contamination. 3. Different resins use different regeneration methods, and softening resin is recommended
to use countercurrent regeneration.
