Questions about the zero potential of the electrolyzer

It is necessary; the zero potential is not just used to detect fluctuations in the voltage of the cell compartment

I have a question: What is zero potential? Is it EDI?

This post was last edited by tclvjian on January 5, 2012 at 10:18. Reply to 3# xushuhang: The cell voltage of an electrolyzer is a crucial parameter for its operation; it directly affects the DC power consumption during electrolysis. For ion-exchange membrane electrolyzers, the cell voltage V consists mainly of the theoretical decomposition voltage V0, the voltage drop across the ion-exchange membrane Vm, the anode overvoltage η_anode, the cathode overvoltage η_cathode, the voltage drop in the electrolyte IR_electrolyte, and the voltage drop in the metal conductors IR_metal. V = V0 + Vm + η_positive + η_negative + IR_liquid + IR_gold. There are many factors that affect the cell voltage in ion membrane electrolyzers, including the material of the electrolyzer, the precision of its manufacturing, the quality of the coatings, and the operating conditions; among these, the distance between the anode and the cathode is also one of the important factors affecting the cell voltage. The smaller the pole distance, the lower the voltage drop across the solution between the anode and cathode, the lower the electrolysis voltage for that cell, and accordingly the lower the DC power consumption. When the pole distance reaches its minimum value, it is referred to as a \"zero pole distance,\" or alternatively as a \"membrane pole distance.\"

It is necessary; by observing the drift of the cell’s zero potential, it is possible to determine which cell in which area is having a problem.

I believe there is no need to establish a zero potential anymore, as the voltage interlock alarm system that groups the three cells together is sufficient to protect the cells; if there is a problem with a particular group, it will trigger an alarm or cause the system to shut down accordingly. Therefore, adding another zero potential is unnecessary. Just my personal opinion; I hope it helps the original poster.

It’s very important that the potential difference be maintained; it allows him to detect many issues

By setting zero potential monitoring points, it is possible to identify some of the problems that arise during the operation of ion membrane electrolyzers in a straightforward manner. 1. The zero potential deviation should be kept within +-1.0V. The key to setting the zero potential is to continuously monitor whether its drift exceeds the allowable deviation, thereby effectively monitoring the corrosion of the electrolytic device caused by leakage current. 2. Setting the zero potential allows for an objective determination of which area of the ion membrane electrolyzer has a problem. If the zero potential is exactly at the middle cell of the ion-exchange membrane electrolyzer, it indicates that the cells and the ion-exchange membrane of the electrolyzer are in good condition and operating properly. If the zero potential suddenly shifts, issues such as grounding or damage to the ion-exchange membrane may occur in the half-cell in the direction of the shift, and timely inspection is necessary.

In my opinion, that 0-voltage design is intended for Asahi Kasei’s cells that come with a high-level tank, while the voltage-group design is suitable for those used in chlorine processing. In both cases, the operating condition of the cells is monitored by measuring their voltage; the goal is the same, but the methods differ. That’s just my personal view.

Regarding the principle of the 0-voltage level, I have already replied to it in this post; please refer to http://bbs.hcbbs.com/thread-962750-1-1.html. As for the slot voltage monitoring devices, they come in groups of three, and their purpose is to allow remote monitoring of the voltage in each unit slot. They are used merely for reference, just as we use a multimeter to measure slot voltages on a daily basis. This voltage is not used for control or interlocking purposes; it serves only as a display mechanism, providing managers with data to assess the operating status of the cells. For example, by creating records for each cell, it is possible to analyze trends in cell voltages. If an increase or decrease in cell voltage is detected, it is necessary to go to the site to determine which specific cell is affected. The potential of cell 0 is the device used to detect and identify cell failures earliest; it is essential to incorporate a interlock system to protect the cells from damage and prevent serious accidents. The link below is a typical example: the failure to invest in interconnections led to the battery cells burning out. http://bbs.hcbbs.com/thread-968961-1-1.html

Hello, Mr. Hu Chang. My previous employer used Sumitomo electrolyzers, and interlock shutdown protection for the electrolyzers was implemented by utilizing a drift value of 0 voltage. When I first came into contact with electrolyzers in chlor-alkali production 8 years ago, one thing that puzzled me was the absence of a interlock for a zero potential; there was only an interlock for the cell voltage (for groups of 6 or fewer cells). Later, in discussions with the Japanese side, it was said that voltage interlock and zero potential interlock work on the same principle and can both serve a protective purpose; therefore, electrolyzers used in chlorine production facilities do not have zero potential interlock. The performance over several years of operation has indeed been good, with several interlock shutdowns occurring in a timely manner. :) I’ll still stick to my opinion.