Ion membrane electrolyzer coating
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This post was last edited by sunjl1981 on 2013-1-7 00:00. Under what conditions does the coating on the cathode/anode plates of ion membrane electrolyzers need to be repainted? # , , &
Generally, the coating life is determined by analyzing the chlorination and hydrogen evolution potentials of the polarization curve. The end of the coating’s lifespan is reached when the anodic chlorine evolution potential is ≥1.172 V vs SCE, or when the cathodic hydrogen evolution potential is ≥1.30 V vs SCE. Of course, it is also possible to determine this by analyzing the composition of the coating layer (although this is not commonly done)
When the anode potential decreases by more than +1.25 volts vs. SCE (3 kA/m2, 90ºC, and 210 g/L-NaCl), the lifespan of the anode coating is considered to be exhausted. The lifespan of the cathode coating is considered to be exhausted when the cathode potential declines below -1.29 volts vs. Hg/HgO (3 kA/m2, 80ºC, and 30 wt%-NaOH).
1. I remember the electrolyzer manufacturer for our company saying that the coating needs to be repainted when the cathode/anode voltage exceeds 300 mV. 2. Generally, manufacturers ensure the lifespan of the coating; within this range, if the cell voltage remains normal or shows no significant changes, it can be used while under observation and replaced upon expiration. Of course, it’s best to return the electrolyzer to the manufacturer for analysis so that the results can be determined. 3. During normal production, if it is found that the cell voltage is abnormally low and the current efficiency has decreased significantly, the possibility of damage to the coating should also be considered. This post was last edited by limingshuguang on 2007-11-29 at 15:21
Under normal circumstances, the electrochemical properties of the coatings on the cathode/anode plates of ion membrane electrolyzers cannot be measured by the units using them, as they lack specialized testing equipment. To conduct such tests, a portion of the electrode must be cut off from the electrolyzer and sent to a specialized facility, which is quite troublesome. Here is a simple method: first, compare the voltage increase after each membrane replacement with that of the previous membrane; second, check the temperature of the electrolyzer. If the temperature is abnormally high, then reapplying the coating to the electrodes should be considered.