What impacts do low cell temperature and low load operation have on the electrolyzer cells and ion exchange membranes?

This post was last edited by huawei on 2009-11-4 at 11:09. For further information, it is a Bitac cell from the chlorine engineering sector; the operating current is 7 KA, the current density is less than 2.2 kA/m2, and the cell temperature is 72 degrees

The current density for chlorine engineering electrolyzers is preferably around 5 KA/m2. Low current has no adverse effect on electrolysis; theoretically, a low current helps improve current efficiency, and it also has no negative impact on the membrane. However, too low a temperature has a significant impact on electrolysis, mainly on current efficiency; the current efficiency at 70°C is lower than under normal conditions. As for low temperatures, they do not have a significant impact on the ion membrane itself. The lifespan of the ion membrane is primarily related to the quality of the saltwater, as well as the stability of the operation process. Of course, it is also greatly influenced by the skill level of the workers in terms of installation and operation.

A low tank temperature results in a high tank voltage, higher power consumption, and lower current efficiency. The higher the temperature, the lower the tank voltage; above 90 degrees, the voltage increases again, and this is due to the gas-liquid ratio

Please do not doubt the conclusion that a low current level is beneficial for improving current efficiency; this was the result of my experiments in my master’s thesis. The main reason is that at low current densities, fewer side reactions occur, meaning that the potential required for such side reactions (such as the oxygen evolution potential) is not reached. At the same time, at low current densities, the concentration of chlorine gas at the anode also increases (provided there are no leaks). Of course, there are also certain limits.

If the tank temperature remains the same, the power consumption is also much lower compared to when a high current is used.

1# 181128425: Generally, no acid is added when operating at low load； The service life of the anode active coating will be reduced ； At low trough temperatures and under low-load operation, the membrane resistance increases, electrolysis efficiency drops, the salt content in caustic soda rises, and the purity of the gas is reduced. Operating at low load for a long time not only results in low output but also high power consumption. The ion membrane experiences overload, which affects its performance and service life. The operating current of chlorine engineering cells is very high; it can reach 14.5 KA at full load. Operating at 7 KA means that the current level is on the low side. I believe that during the current-raising process, the time during which the cell operates at a low current should be minimized, so as to reach the planned operating current as soon as possible and then operate normally.

When the tank temperature is low, the tank voltage must be high, resulting in high power consumption and reduced current efficiency. There are also more side reactions at the anode, leading to an increase in chlorate levels; this increases the corrosiveness toward the anode electrodes. Meanwhile, the dechlorination system does not function properly, and operating at a low current level is definitely not beneficial