Regeneration; Advantages Of The Laboratory Tests - ELECTOR PUREval MX-G Manuel De L'utilisateur

Glass column for laboratory tests with ion exchange resins

4.12 Regeneration

Many different processes have been developed for the regeneration of ion-exchange resins.
The simplest and most common method is DC regeneration. With this method, the regeneration agent
and the process medium flow through the resin bed in the same direction.
The first step in cocurrent regeneration is always backwashing the resin with fully demineralized water
in order to loosen the compaction of the resin bed and remove impurities. In general, the entry of
particles into the resin bed should be prevented by prefiltration of the process solution.
After the backwash, the regeneration is carried out, followed by the slow displacement rinse and the
final rinse.
A more effective regeneration of the resins can be achieved with countercurrent regeneration. With
countercurrent regeneration, the regenerant flows through the resin bed against the normal operating
direction, which results in significantly less slip. With the PUREval MX-G ion exchange column,
countercurrent regeneration can be easily implemented with an additional pump.
In the case of countercurrent regeneration, which is normally carried out using the upflow principle,
turbulence in the resins must be avoided. In order to stabilize the resin bed, the resins have to be
driven to the upper filter plate at high speed. Alternatively, the free space above the resin bed can be
filled with cotton wool or special inert resins.
In laboratory tests, deionized water is always used to dilute regeneration agents and for the rinsing
processes. This simplifies the calculation of the capacity and also avoids additional loading of the
resin bed with other ions.

4.13 Advantages of the laboratory tests

With controlled laboratory tests, a large amount of data and experience can be collected for individual
process applications before an ion-exchange system is implemented in real operation.
The evaluation of all individual steps under controllable, reproducible conditions is the most reliable
and economically sensible way to evaluate the behavior of the ion-exchange resins and to gather
knowledge for a final ion-exchange system.
The laboratory tests are used to proactively optimize processes. With the data collected in the
experiment, the concentration of regeneration agents, the flow rate and other decisive parameters can
be optimized in advance before an ion-exchange system goes into operation on a real scale.
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