The membrane acceptance test procedure will provide the end user at a fixed feed flow a permeate quantity per element, normalized for pressure and temperature. Membrane testing will give many insights for the user. Also by measuring the conductivity in the feed water and permeate the salt rejection can be calculated. More specific demands of the end user concerning the maximum levels of chloride, conductivity, Boron or others in the permeate can be monitored per element using this test.
Membrane elements sold by membrane manufacturers are within well defined specifications. Performance data of production and salt rejection are linked to a specific membrane type and mentioned in the membrane manufacturers brochures. Selection of which element, how many and in what optimal configuration they should be used, can be done by clients with the aid of the manufacturers calculation programs. Once this process is followed by an order at a certain time the elements will be delivered to be placed in the clients plant. Before doing so a membrane acceptance test is recommendable. Checking the values of production and salt rejection of every single element and registration of these data will be helpful in loading the pressure vessels and stages. In this way the elements can be also followed in their performance over time and projections can be made if and when to replace them.
The acceptance test and Global Membrains
In order to conduct a membrane acceptance test there is a need for a registration system at which Global Membrains can help. Also a testrig to test one or two elements should be available. This test rig needs to be equipped with flowmeters, manometers, thermometers and conductivity measurements. The membrane acceptance test includes the comparison of the data provided by the manufacturer and the data found on the testrig. By registering the performance data of every uniquely numbered element, over time an element can be extracted to compare the previous data with the actual data in a new membrane acceptance test. In this way the lifetime of an element can be roughly determined and replacement can be projected.
The data of the membrane acceptance test can also be helpful in checking the effectiveness of cleaning procedures by comparing the actual data against the original data. Even more the test rig used for the acceptance test can be used in this case to conduct tests to find the most effective cleaning procedures, which per definition are not necessarily the same for front and last end elements.
Global Membrains can assist in a membrane acceptance test by bringing in our know how on set up of the test rig, the normalization of the data and its registration.