Will a gas phase region form inside the electrolyzer after it loses power, due to the inability to add liquid in time?
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After a sudden power outage of the electrolyzer, two possible scenarios can be imagined. The first is that there is a large amount of gas inside the electrolyzer; since no more gas is being produced due to the power outage, the remaining gas escapes instantly, causing the liquid level to drop suddenly and creating an upper gas phase region, which results in a disruption in flow at the outlet of the electrolyzer. The second case is one in which there is relatively little gas inside the electrolyzer, with liquid making up the majority. If power is cut suddenly, the electrolyzer stops generating gas; this hardly affects the liquid level inside the electrolyzer, no gas bubbles are formed within it, and there is no interruption in the flow at the outlet of the electrolyzer. You feel that that scenario is more realistic. The reason for raising this question is that the operating procedures of Beihua Machinery state that in the event of a complete power loss, pure water should be poured into the electrolyzer for 10 minutes before the tank contents are drained and the tank is cleaned. So the question is: are these 10 minutes mainly required because a weathering zone will form and water needs to be added to displace the gas in the tank, or will no such weathering zone arise, with the water being used primarily to dilute the saltwater?
Modern naturally circulating electrolyzer designs all include a head tank, so the outlet of the electrolyzer does not experience a flow interruption for a certain period of time
Theoretically, it is like this, but if the first situation occurs, there will be a brief interruption in flow even with a high-level tank; this does not happen in the second case.
It seems that the operation of the North Chemical Machine is based on determining whether there is a power outage in the anode and cathode fluids. If the entire system loses power, it’s not possible to inject pure water either; one can only use a high-level tank to replace the fluid for a few minutes, then seal the tank and wait for power to be restored. If it’s the level of the fluid in the high-level tank that increases, it means that the circulation of the anode and cathode fluids has stopped, and pure water needs to be used to displace the gases inside the tank
Regarding sudden power outages, it is necessary to check whether there is a gas phase space. During such outages, observe whether the discharge pipe overflows; no overflow indicates the first scenario, while overflow indicates the second scenario
This time period is short; if it can be detected directly, then the time is relatively long. In such cases, when chlorine comes into direct contact with the ion membrane, there are noticeable changes in the voltage and current efficiency after the system starts operating.
I’m not sure about other people’s situations, but our electrolyte tanks do not overflow in the event of a sudden power outage
That means the first scenario is more in line with reality.
It depends on the power outage situation – do both the liquid supply pump and the electrolysis system lose power at the same time? If that’s the case, a process without a high-level tank is very dangerous. In processes that use a high-level tank, these two possibilities are less likely, as the volume of the high-level tank is generally sufficient to ensure the safety of the electrolytic cell in the event of a power outage. Of course, if too many unit cells are added or if the volume of the high-level tank is altered, things become more uncertain.