Summary of EDI membrane unit failures

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This post was last edited by hesonchang214 on 2020-2-7 21:44. 1. Typically, the EDI module operates for extended periods under conditions of high current and low flow rate, which prevents the heat generated from dissipating. As a result, the membranes near the electrodes become heated and deformed, the pressure difference in the concentrated water increases, and the quality and quantity of water decrease to varying degrees. 　　2. If the EDI module is not maintained for an extended period, scaling occurs on the diaphragms and channels, the pressure difference between the inlet and outlet water increases, which also leads to a decline in the quality of the produced water. Additionally, the voltage rises and the current cannot be adjusted, resulting in the module becoming unusable in the end. 　　3. When the EDI equipment is shut down, no protective measures are taken for the EDI modules, and regular maintenance is not carried out over time; as a result, organic substances accumulate on the membranes and channels of the EDI system, leading to an increase in the pressure difference between the inlet and outlet water. This causes a decline in the quality of the produced water, an increase in voltage, and an inability to regulate the current, ultimately rendering the system unusable.

4. When the EDI industrial ultra-pure water system is operated manually, powering it up when there is a lack of water directly causes the membranes and resins to overheat and carbonize. Cleaning efforts prove ineffective, and the system becomes unusable.

5. During the cleaning process, the cleaning and disinfection agents used can damage or break the EDI resins, resulting in an increased pressure difference between the inlet and outlet water. This leads to a decline in both the quality and quantity of the produced water.

6. The current and voltage exceed the specified values, or there are human errors in operation; improper system maintenance and management occur, with failure to comply with the operating conditions required for the EDI system.

7. The absence of a pre-filter before the water enters the EDI system allows foreign objects to block the channels, increasing the pressure difference between the inlet and outlet water. This results in a significant reduction in the amount of water produced, and cleaning efforts are ineffective. Other issues include inadequate pretreatment (such as softeners, sulfite addition systems, RO units), control system failures/disfunctions (such as safety interlocks and low-flow protection problems), and improper system design (e.g., failure to discharge the initial output water from the RO unit).