Reasons for high slot voltage and low current efficiency
Thread Content
This post was last edited by sunjl1981 on 2013-1-7 at 00:26. Electrolyzer: Beihua Machinery ZMBCH-2.7; Ion membrane: Asahi Kasei F6801. This unit came online in September 2008 and operated for over a month before being shut down for 3 months due to the economic crisis. During that time, the membrane was washed once a week to keep it moist. Now that it has been restarted, it has been found that the total voltage of this electrolyzer is higher than that of the others. Experts, please provide some guidance. This post was last edited by yzhms on 2009-3-13 at 14:09. # hcbbs
1) Is the ion membrane moistened regularly in accordance with the technical requirements of the membrane supplier, and is the ion membrane damaged?； 2) Is the electrolyzer properly sealed, and have the iron ions adsorbed on the cathode been oxidized, thereby reducing its cathodic performance? ； 3) Continue to observe whether it can return to its original level after driving for a while ； :P Last edited by yzhms on 2009-3-13 14:23 ]
Is the high cell voltage due to the electrolyzers or a problem with the ion exchange membrane? Our company also uses the ZMBCH-2.7 model from Beihua Machinery, with Asahi Kasei’s F4403D membrane. During testing, two cells were put into operation first; the third cell was started two months later than the first two. Yet now, the total cell voltage of the third cell is about 4V higher than that of the first two. I believe the issue lies in the way the electrodes are stored and maintained in these electrolyzers. I would like to ask if other manufacturers have encountered this problem and if anyone has analyzed its causes.
I don’t know how high the voltage is in the owner’s case. Based on my experience, this situation is likely caused by blisters on the membrane; the voltage will decrease after the device has been running for some time. Also, it would be more appropriate to say a financial crisis at the moment, I think
There are likely two reasons for this: during parking, the cell was not filled with fluid and pressurized, so the membrane may have adhered tightly to the cathode. Nickel from the cathode penetrates into the membrane, and the lower cell temperature during operation leads to an increase in cell voltage. If it is the latter, the trough pressure should recover in about a week.
I think there must be a problem with the electrodes stored in the electrolyzer. We took measures to keep them moist while the system was shut down, and by maintaining a nitrogen atmosphere, the electrodes wouldn’t stick to the cathode side. What exactly caused the problem with the electrodes? Did the coating come off? This post was last edited by haining on 2009-3-13 at 13:10
The electrodes consist of a nickel cathode and a titanium anode; under normal conditions, the coating does not come off, especially in new cell compartments. If there is a problem, it is likely that it has been contaminated by impurity ions.
Is it possible that it’s due to incomplete replacement after draining? To check whether the coating has peeled off, the battery cell can be opened to examine whether there are any debris on the surface of the membrane
After parking, iron deposits on the surface of the coating, which affects the active coating of the cathode.
Reply to the moderator: Cathode contamination in the electrolytic cell is indeed a problem. I have discussed this issue with the manufacturer, and we have also encountered situations where the cell voltage increased after the cell was left idle and moistened; the manufacturer advised us to fill the cell with liquid to maintain moisture levels. I hope everyone will engage in a thorough discussion on this topic.
Our company also uses the Beihua Ji ZMBCH-2.7 model, with Asahi Kasei’s F4403D membrane. Since it was put into operation on May 1, 2006, we have not encountered the problems described by your company. I believe that the issues arise from 1. bubbles forming on the ion membrane, and 2. operators failing to follow the operating procedures, which leads to deformation of the electrolyzer’s electrode grids and an increase in cell voltage.
I agree with the above. In my opinion, the cell voltage is primarily composed of pipeline overvoltage + solution overvoltage + cell overvoltage + constant voltage; therefore, these factors should be taken into consideration: handshake
I agree with what was said above; a high slot voltage is caused by various factors. Excess electrical losses, unless utilized for some purpose, will inevitably lead to a decrease in current efficiency.
First, check the tank temperature; second, check the membrane. The focus should probably be on checking the electrodes as well – conduct an electron microscope or XRD analysis