How should Asahi Kasei’s cathode-type natural circulation electrolyzers be maintained after being shut down in winter?
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This post was last edited by sunjl1981 on 2013-1-6 at 21:47. Hello everyone, our facility has stopped operations in winter. We are wondering whether it is reasonable and feasible to proceed in this way with the electrolyzers during this period of inactivity; we would appreciate any advice from those with more experience. Below is an overview of our current maintenance practices: the electrolyzer is in a locked state, the oil pressure is at 7 MPa; the membrane is moistened once every seven days. The room temperature is around 5°C. Is this temperature suitable, and what impact does it have on the membrane? Additionally, we compress the gaskets of the electrolyzer again at pressures of 7 MPa–9 MPa–7 MPa once a week. Could this cause damage to the electrode grids and the membrane over time? O(∩_∩)O Thank you! # hcbbs
This post was last edited by 181128425 on 2010-1-18 at 23:24. Shutting down the electrolyzer in winter is probably the worst solution (it has many drawbacks); it should not be done unless absolutely necessary. Doing so causes a lot of problems and is difficult to handle, especially when the entire system is shut down – that’s even worse. You’ll know when you start it, hehe. It’s still necessary to apply a coating film; as for squeezing the electrolyte cell again, I don’t think it’s necessary to do so. Is it fear that the gasket will contract due to the cold weather? We usually squeeze it when opening the electrolyte tank and when using new gaskets; it’s easier to squeeze at higher temperatures, while it’s more difficult at lower temperatures. We’ve never encountered such a situation before.
Thank you for your guidance, sir. So we shouldn’t compress the gasket at this point. We have stopped the operation and flushed all of the cathode systems clean, but there is still saltwater in the anode systems. The resin tower has been regenerated and is now soaked in saltwater. Also, we didn’t use nitrogen when cleaning the tanks, as the operation was stopped; is it okay to drain the liquid without using nitrogen? I opened valve No. 18 to allow air to be drawn in for draining – is this approach acceptable? 2# Jianao BuXun
The room temperature had better be a bit higher, as ion membranes are also sensitive to freezing. It’s best to be over 10°
If your gasket inserts last for a long time, be careful when squeezing them. If the gasket has aged, during operation of the machine, with a cell temperature of around 88 degrees, pressing to 9 MPa might not cause any problems. However, after the machine is stopped in winter, as the temperature drops, pressing to 9 MPa may damage the aged gasket. Therefore, it is essential to closely monitor the cell while applying pressure and adjust it gradually.
Prolonged immersion in saturated salt water tends to cause crystallization, right? I think it’s not good to keep something in salt water for too long. It doesn’t matter if there’s no nitrogen; just pay attention to the pressure difference gauge and release the gas slowly – it’s no big issue.
To prevent freezing in resin towers, pure water should be used for flushing, not saline water； To prevent the membrane from drying out, it is recommended to clean the tank once a day.
Ion exchange resins should be soaked in saltwater of a certain concentration to prevent freezing from damaging the resins.
Thank you. Our brine isn’t saturated, but it still has a certain concentration, which prevents crystallization at low temperatures. In the absence of nitrogen, when cleaning the tank, the valve numbered 18 should be fully opened to allow air to enter the tank so that the liquid can be drained; that’s what I do by opening this valve. I’m not sure if there’s a better way; I hope the expert can give some advice. 7# Uncooperative
Thank you for your valuable advice. I think, given our current situation, we should reduce the pressure – perhaps keeping it around 4 or 5 MPa. Do you think that’s okay? I don’t see any need for such high pressure; high pressure isn’t good for the gaskets. It’s always beneficial to learn more