What effect will adding chlorine water to a diaphragm electrolyzer have?

The chlorine water you mentioned is salt-containing chlorine water, right? It shouldn’t have a significant impact. The important thing is to control the concentration of the saltwater properly; in our company, the concentration of the saltwater used in the tanks is kept at around 250 g/l.

In my opinion, the presence of free chlorine in diaphragm alkaline brine should have no effect on the electrolysis reaction, but the following points should be taken into consideration: 1. Increased pipe corrosion. Because the chlorine water produced by the chlorine addition wash contains free chlorine, which may lead to increased pipe corrosion ； 2. There are increased requirements for controlling the saltwater concentration. The salt content must be adjusted continuously based on the chlorine water flow rate; otherwise, a low concentration of saline water may cause the tank voltage to rise and increase power consumption ； 3. The location where it is added must be chosen carefully; otherwise, uneven saltwater concentration may cause abnormal voltage in a single tank.

In my opinion, the presence of free chlorine in diaphragm alkaline brine should have no effect on the electrolysis reaction; the following should be considered: 1. Lining the salt water pipe with rubber. 2. Control the concentration of the saline solution; it is best to add a small container before it enters the electrolytic cell to ensure even mixing.

Be careful of corrosion in the brine preheater; most brine preheaters using diaphragm alkalis are made of carbon steel, and chlorine water will cause rapid corrosion, so it is better to use titanium material instead. The brine fed into the diaphragm cell should be saturated; after adding chlorine, it is necessary to check whether it remains within the specified technical parameters. It is advisable to use steel-lined pipes for the brine main lines.

Chlorine water has little effect on diaphragm alkalis; it can be added to the diaphragm brine, but it must be added after the brine heater to prevent corrosion of the heater by chlorine water. Additionally, a static mixer must be installed in the brine pipeline to ensure even mixing of chlorine water with the brine. The pipeline should also have good corrosion resistance; it is recommended to use rubber-lined pipes. The concentration of the refined brine should be increased accordingly based on the amount of chlorine water added, in order to fully ensure the concentration of the brine fed into the tank.

1. Generally speaking, the amount of chlorine water produced is not very large, compared to the amount of water containing salt that enters the tank； 2. This is indeed an optimization effort for energy conservation and emission reduction ； 3. Has your organization stopped carrying out this operation? Do you have any relevant experience to share? ； 4. Ion exchange membranes are definitely not suitable, as they contain impurities; they are also not viable before the resin column. This post was last edited by yzhms on 2008-1-18 12:22]

Does the concentration of 250 g/l mentioned above refer to ion-exchange membrane cells?

The 250 g/l mentioned above does not refer to ion exchange membranes (where the concentration of brine is between 200–210 g/l); for membrane caustic, the brine concentration is between 310–320 g/l. There might be a mistake here.

The diaphragm will have no effect. . . . . . . . However, it is important to note that corrosion protection of pipeline equipment is of the utmost importance. .

I don’t agree with the claim that there is no impact. I wonder what the purpose of adding chlorine water to the brine at your factory is? In my opinion, chlorine water contains a large amount of free chlorine and hypochlorite ions, with only a small amount of salts. There are generally only two sources of chlorine water: one is the chlorine water cooled by the cooler, and the other is the recycled chlorine water from the chlorine water scrubber tower. The amount of salt is not high; generally, manufacturers use post-treatment processes to recover chlorine. There are two drawbacks to adding it directly to saltwater: 1. It affects the concentration of the saltwater in the tank. 2. It increases the concentration of hypochlorite on the anode side, which can easily lead to excessive levels of chlorate in the electrolyte. However, there is one case in which it can be added directly to saltwater, but post-treatment is still required; that is, if the ammonia content in the saltwater is too high, chlorine water can be added to oxidize the ammonia present in it. Generally, it is mainly used before heating the brine, and a dechlorination device is also required to add sulfite to remove free chlorine and hypochlorites. This is a method for removing ammonia using saltwater.

Disagree. Although chlorine water is limited, it can still be harmful. 1. Corrosion – no need to go into detail here. 2. It causes concentration differences, as mentioned by a few people upstairs as well. 3. It causes a decrease in the concentration of brine, which in turn leads to a reduction in the electrolyte concentration and an increase in steam consumption. 4. A brine concentration below 300 may increase side reactions and reduce chlorine concentration (while increasing oxygen content) ； Oxygen has a significant corrosive effect on the anode sheet coating. Taken together, this may have a certain impact on production costs. Perhaps considering the use of chlorine water to produce sodium hypochlorite as a by-product could be an option. (Your factory surely has a dechlorination tower, right?) ) The above are merely personal opinions.

It can be tried out; although there will be many side effects, it can increase the production of chlorine and reduce the formation of by-products