The issue of draining liquid when shutting down ion membrane cells!

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This post was last edited by sunjl1981 on 2013-1-6 at 22:44. The “battery effect” that occurs during parking involves the reduction of chlorine atoms to chloride ions at the anode, while at the cathode the metal oxidizes, leading to corrosion. Similar to when the membrane is installed in reverse, this reverse current can also cause bulging in the membrane. Reverse current can occur when power is first applied to a stopped electrolyzer. Since this reverse current causes water molecules to migrate in the opposite direction, it reduces the moisture content of the membrane, which can lead to a deterioration of the physical properties of the carboxylic acid layer and result in an irreversible decrease in current efficiency. Moreover, reverse current can cause NaCl to deposit within the membrane; once such deposits form, they can dissolve and create holes during cleaning procedures when the system is stopped. In situations of unstable operation, this can lead to physical damage and the formation of holes. Therefore, it is necessary to minimize periods of shutdown as much as possible. Frequent starting and stopping cause the membrane to expand and contract due to temperature changes, leading to physical relaxation of the membrane and a decrease in its current efficiency. The contraction and expansion of the membrane cause it to wrinkle, and the electrolytic gas-phase products may penetrate into these wrinkles, blocking part of the membrane’s effective surface area and resulting in an increase in resistance and a rise in cell voltage. The membrane wrinkles, and coupled with unstable pressure differences during startup and shutdown, large positive and negative pressure differences can easily occur. This causes friction between the membrane and the electrodes, leading to pinholes or physical damage. It also continuously disrupts the \"dynamic balance\" within the electrolyzer, resulting in \"over-fatigue\" of the ion membrane and a decrease in its elasticity, which makes pinholes more likely to appear. Asahi Kasei requires that, in the case of a shutdown lasting more than 2 hours, the electrolyte in the cells be quickly drained and washed; for shutdowns of less than 2 hours, the concentrations of the anode and cathode solutions must be strictly controlled. Otherwise, reverse migration of water in the cathode solution can cause damage to the interior of the membrane, while too low a concentration of the anode solution can lead to membrane damage and bubbling. In some domestic factories, the process of stopping operation and draining liquid is not carried out in a timely or thorough manner, which causes the lower part of the membrane to remain submerged in water and results in severe bubbling. Failing to drain the liquid quickly when stopping creates conditions for the formation of reverse current during shutdown, causing the membrane to bubble. This post was last edited by Captain Yang on 2008-5-17 12:55 ] # , , &