Asahi Kasei 140 cell membrane leakage problem
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This post was last edited by sunjl1981 on 2013-1-6 22:58. I have a question and I would like to ask everyone for advice. Asahi Kasei 140 piece natural circulation tank. During operation, a piece of the tank was found to be discolored and leaking, and the tank was stopped to change the membrane. After the replacement, when the membrane leakage was measured, 10 membranes were found to be leaking, and sometimes even 20 or 50 membranes were leaking. Please help. What is the reason for so many membrane leaks? Why are these membrane leaks not shown during operation? (The premise is that all analyzes are qualified and there are no human reasons) # hcbbs
It is not clear how long the membrane has been used, whether it is the first time to replace the membrane or whether it has been replaced several times. If it is the first time to replace the membrane, ask the electrolytic cell supplier and the membrane supplier to jointly analyze and solve the problem. If the electrolytic cell has been repaired, it is caused by the cathode or anode. Find a repair unit to solve it, otherwise it will still leak even if the membrane is replaced with a new one.； If no leakage is found during operation, it must be a slight leak. It will gradually disappear.···
There are some contradictions mentioned by the poster. If all the analyzes are qualified and there is no human reason, there cannot be so many membrane leaks. It should be that there is a problem during membrane replacement or membrane leak testing.
Is it a large tear? Did you find the membrane building as soon as it was filled with liquid? If so, it is probably a quality problem with the membrane, probably the F4402 membrane. This kind of membrane has no problem in water leak test and membrane leak test. However, once filled with liquid, the membrane begins to shrink when encountering alkali solution, and the stress increases. If the tensile strength of the membrane is exceeded, long cracks will easily appear.
The performance of membrane aging, which generally does not occur with new membranes
The new tank has been open for more than a year, and they are all new molds. They have not been replaced in the middle. It is possible that they are aging. Why is it that only one film is found to be leaking? After replacing this membrane, you need to perform a membrane leak test. At this time, you will find that several membranes are also leaking. Replace these membranes. After replacing them, do a membrane leak test and replace them again if there are still membrane leaks. That's it. I suspect it's a problem with squeezing and retracting the trough.
I think the possible reason: At first, if one membrane leaks a lot or is even torn, the amount of leakage is very large, and other membranes with small leakage cannot be detected. Only after the membrane with severe leakage is replaced can the other membranes be detected. Measures taken: If it is found that there is a large leakage, try to block the anode outlet with something, and then check whether other membranes are leaking.
It may be pinholes or blisters. During operation, the membrane will not behave in high-concentration alkali solution, but it will appear after shutdown. I haven't touched it yet, just for reference.
The membrane leak test pressure is unstable and misjudged.
It may be caused by not arranging the unit slots neatly during extrusion. We also encountered this problem. The gaskets and ion membranes of several unit slots were broken! Therefore, this problem will inevitably occur in electrolytic cells with extruders. Especially when there are many novices, this kind of mistake can easily occur if the operation is not careful. Therefore, you must pay attention to the detailed operation of the maintenance tank, and try to conduct theoretical and practical training on operating procedures before maintenance!
Personally, I think there is one membrane that leaks badly, and other membranes also have pinholes, which have less impact during operation and are not easy to detect.