Process Parameters; Operation In Laboratory Tests - ELECTOR PUREval MX-G Manuel De L'utilisateur

PUREval MX-G
also provides the necessary information about the loading of the column.
The samples should not be taken from the collecting container, but rather at the time of sampling from
the drip nozzle of the ion exchange column. Following this principle you can record exact breakthrough
curves.

4.10 Process parameters

The ideal process conditions vary widely depending on the application. For processes that have not
yet been fully developed or for which no empirical values exist, the optimal specific flow rate should
first be determined as part of a laboratory test.
In most low load applications and conventional ion exchangers, the flow rate can be up to 50 BV
/ h. Even higher flow rates are sometimes used. In special process applications, particularly in
applications with selective exchange resins, the flow rates should be at a level of 1 - 10 BV / h.
In order to achieve maximum regeneration of the resins, the regeneration process is always carried
out at low flow rates of 1 - 6 BV / h. The regeneration process is followed by a slow displacement
rinse and a final rinse to ensure the best possible removal of the regenerant.
In water-free process applications, the resin is usually regenerated using water. In this case, the
process medium must first be displaced with water. This process is called „sweetening off" and after
regeneration, when water is again displaced with the process medium, called „sweetening on". These
terms come from the sugar industry, where ion-exchange resins and absorber resins are used in a
variety of ways.

4.11 Operation in laboratory tests

Once the laboratory test has started, it should not be interrupted or paused, but should be carried
out until the resins are completely exhausted. The experiment should not be paused. Most ion-
exchange processes are reversible and once the flow is stopped the resin bed tries to reach a state
of equilibrium. As soon as this happens, ions can move back from the resin into the liquid. This can
cause the resins to run out prematurely and result in incorrect test results.
Under normal conditions the resin should always be covered with liquid. The column should never be
emptied so far that air bubbles creep into the resin bed. Air bubbles are difficult to remove and worsen
test results.
Three consecutive cycles should be performed with reproducible results before changing any
operating conditions to optimize performance.
It typically takes two to three test cycles to get reliable results.
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