Ion membrane leakage
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This post was last edited by sunjl1981 on 2013-1-6 at 23:38. These days, taking advantage of the low load, repairs were carried out on individual electrolyzers; 7 new membranes were installed in one of them, and membrane leak tests were conducted three times. At a pressure of 4.9 M water columns at the anode outlet, no bubbles were detected during all three tests, confirming that the electrolyzer was in good condition. Four days later, before integrating this electrolyzer into the system, two more membrane leak tests were performed, with no signs of leakage found again. However, when current was applied to this electrolyzer, new leakage points were discovered. The coloring of the hoses happened late, and the cell voltage was low – it’s frustrating! I hope fellow experts can help find a solution and discuss this issue. # &
This situation is quite common, as it is difficult to detect leaks in membranes when there are small pinholes in them. Also, is it correct to say that the cathode outlet pressure is 4.9 mH2O? Asahi Kasei requires nitrogen to be introduced into the cathode at a pressure of 0.5 mH2O.
A slow change in color does not necessarily mean there are defects in the membrane; this can be determined by measuring the chlorine purity and hydrogen content in the unit cell, as well as the voltage of the unit cell
A slow change in color indicates leaks in the membrane; since the cathode pressure is higher than the anode pressure, the anodic chlorine generated during electrification reacts with the NaOH that seeps back from the cathode. The color at the anode outlet changes only when the amount of chlorine exceeds that of the NaOH seeping back.
It’s not necessarily a problem if the color change of the newly installed film is slow, as the new film also changes color more slowly while driving compared to older films