How to stably control the cell voltage of an ion membrane electrolyzer

The 2400 you mentioned refers to the AC power consumption, right?

Also, try to minimize the number of starts and stops

In addition to controlling the quality of brine, increasing the amount of acid added, raising the temperature of the electrolytic cell, and appropriately increasing the gas phase pressure. Also, it is necessary to control the concentration of the catholyte well, as an increase in concentration will raise the cell voltage.

Is your power consumption close to 2400? It seems higher; ours is around 2150.

In addition to the various indicators mentioned by the original poster, I believe safe and stable operation is very important; efforts should be made to minimize the number of starts and stops, as well as the fluctuations in current. Parameters such as concentration and acid addition also need to remain stable, so that power consumption will be stable or even decrease.

First, let’s take a look at the components of the cell voltage: theoretical decomposition voltage, anode potential, cathode potential, anode hydraulic drop, cathode hydraulic drop, membrane pressure drop, and first-type conductor pressure drop. The level of the theoretical decomposition voltage is primarily influenced by the cell itself； The anode potential takes into account, on the one hand, the condition of the coating; on the other hand, it relates to the impurities attached to the coating; and furthermore, it is related to some side reactions that occur during the discharge of the electrode ； The cathode potential is the same as well ； The anode hydraulic drop is mainly influenced by the NaCl content, cell temperature, and certain impurities in the brine ； The catholyte potential is the same as well ； The membrane pressure drop is primarily influenced by the quality of the brine, the addition of acid, operating time, tank temperature, etc. Starting and stopping (especially sudden stops) have a particularly significant impact on the performance of the membrane.

Frequent fluctuations in current are strictly prohibited, as such fluctuations have a severe impact on the lifespan of the anode coating (no tests have been conducted on the cathode).

The electrolyzers in our company often stop operating, and many membranes have had to be replaced, resulting in significant financial losses. After reading your responses, it seems that there can be substantial benefits. I am currently conducting statistical analysis on the voltage of each electrolyzer, but I’m not sure what use that will be

1. Minimize the number of start-up and shutdown cycles. 2. Ensure the quality of brine to maintain the current efficiency of the ion exchange membrane and minimize contamination of this membrane. 3. Guarantee the quality of the coatings on the anode and cathode. 4. Control the parameters of the medium fed into the cell. 5. Select the most appropriate current density

The 2400 kwh/t figure I mentioned refers, of course, to the AC power consumption, and it’s quite high indeed. Our membranes and cells have been in use for a long time now; I’m not sure what model of ion exchange membranes everyone is using. Also, should the saltwater concentration be kept high or low? In fact, the cells shouldn’t operate continuously for too long, as even high-quality saltwater still contains certain impurities. Under certain conditions, after the cells have been running for a long period, it’s necessary to stop them for cyclic cleaning, and after restarting them, the cell voltage will decrease as well. What is the acidity level at the inlet and outlet of the anodes in your cells? Here, no matter how much acid is added at the inlet, the acidity there does increase, but the acidity at the outlet remains very low.

I fully agree with the views of my colleagues above. But I think there is one more factor that cannot be ignored—the selection of ion membrane models. Different types of membranes have varying voltage drops, and companies should choose the appropriate ion membrane based on the design of their electrolyzers as well as the characteristics of their chlor-alkali systems (such as the quality of the brine and whether the systems are started and stopped frequently).

The quality of the membrane, whether there is any damage to the frame, as well as the stability of the current in the slots mentioned earlier, along with the control of concentration, temperature, and the amount of acid added. This post was last edited by limingshuguang on 2008-1-14 at 13:26.]

Current efficiency and voltage reflect the operational management level of a device; when it comes to voltage specifically, we need to pay attention to the following issues. I. Quality control of secondary brine: The contamination of membranes by metal ions is, in essence, a cumulative process; therefore, the parameters of secondary brine should be kept as low as possible. In particular, magnesium and nickel have a significant impact on voltage, so attention should be paid to the analysis of these two elements. II. Protection of cathodic and anodic coatings: Taking the cathodic coating as an example, attention must be paid to the effect of reverse current on it. When reverse current is present, the cathode becomes the electrode that undergoes dissolution, the active coating gradually wears off, and the cell voltage rises accordingly. Another issue is the corrosion of the anode caused by pinholes in the membrane; ion exchange membranes with pinholes should be replaced promptly. Adding acid to the anode also helps to reduce the corrosion of the anode coating caused by the reverse migration of OH-. III. Minimizing the number of stops as much as possible is beneficial for maintaining the stable performance of the electrolytic cells and membranes.