How does ion membrane leakage affect cell voltage?
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This post was last edited by sunjl1981 on 2013-1-6 19:52 How does ion membrane leakage affect the cell voltage? We had a film leak. The cell voltage was about 0.6V lower than other unit cells at the initial stage of current increase. Within two days after the current was fully increased, the cell voltage rose all the way to about 0.2V higher than other unit cells. Why does the tank voltage increase first and then decrease? If the cell voltage decreases in the initial stage of leakage, it is just because the ion membrane voltage drop is reduced. In that case, it will not be lower than about 0.6V, because the membrane voltage drop is far less than 0.6V. There should be other reasons besides the membrane voltage drop. If the cell voltage rose again later because the membrane leakage corroded the electrode coating, thereby increasing the anode overvoltage and increasing the chlorine evolution potential, then why has the cell voltage remained normal and stable after replacing a new membrane for more than 24 hours? The coating did peel off but it was not serious. It should be caused by reasons other than the coating that caused the tank voltage to increase. Help ~ hcbbs hcbbs
“Within two days after the current was fully charged, the cell voltage rose to about 0.2V higher than other unit cells." This means that the damage to the electrode coating of the anode is not very serious. This 0.2V should be caused by the oxygen evolution caused by the change in the PH of the anode. Where is the author's electrolytic cell? Can the chlorine be taken out of the unit cell to check the purity? If the anode electrode is corroded, it is irreversible!
From Beihua Chemical Machinery, the purity of chlorine at that time was about 97%
The reason why the cell voltage is low is because the membrane leaks, causing the anode to contain a large amount of alkali, and the anolyte resistance is reduced. I think the reason why the tank pressure is high is because the membrane leakage gradually becomes serious, the negative reaction in the anode chamber intensifies, the temperature is too high, the anolyte is close to boiling, and the aeration degree increases, which causes the tank voltage to rise.
I don’t know if this problem of the Wei family has been solved. We all drive the car and if the tank voltage differs by 0.6v when increasing the current, we will just stop the car and deal with it!
A difference of 0.6V is considered quite large. For safety reasons, it is better to stop the battery. Regarding the rise in tank pressure in the later period, there are many influencing factors. 1. Due to membrane leakage, the migration of OH- into the anode chamber increases, which promotes the oxygen evolution reaction (the influence of concentration on the oxygen evolution reaction). 2. The tank temperature rises, and the temperature that should be taken away by the catholyte returns to the anode chamber due to membrane leakage. If the temperature of the tank frame rises, the metal resistance will increase. Regarding the increase in bubble rate, this may also be the reason. 3. Side reactions increase, and clo- will also discharge.
Our company is also a Beihua electromechanical tank. If the voltage of a single tank is 0.6V lower than the average tank voltage, stop directly and replace the ion membrane.
For an ion membrane with a low cell voltage, when doing a membrane leak test, does the air leakage amount not exceed the standard?