Utilization of the heat generated by ion membrane electrolysis of wet chlorine gas
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Our company uses natural circulation electrolyzers produced by Beihua Ji. In the design, the brine treatment unit is located at a distance from the electrolysis unit; the brine that enters the chelating resin tower is heated using steam. After passing through the resin tower, it goes into the concentrated brine tank, from where it is pumped into the concentrated brine sump. There is no heat exchanger between the concentrated brine tank and the concentrated brine sump. The wet chlorine gas produced by ion membrane electrolysis enters the chlorine water scrubber tower in the chlorine drying section via valve 216. The heat from this wet chlorine gas is not being fully utilized. How can this heat be put to use? Can it be used to heat the brine fed into the electrolyzer? Feel free to give your advice.
It’s a great suggestion; this latent heat can be utilized in the design of other electrolyzers. On one hand, it allows for the recovery of the heat contained in the water vapor in chlorine gas, and on the other hand, it reduces the volume of chlorine gas, which facilitates its transportation, enables smaller diameter chlorine gas pipes, and thus reduces costs. This portion of heat can be entirely used to heat the brine fed into the cell, and it has been successfully applied in the design of other types of electrolyzer processes.
Heating brine is less effective than heating filtered salt water; by using the wet chlorine gas produced in the electrolyzer to exchange heat with the filtered salt water, some of the moisture in the chlorine gas can be condensed. After exchanging heat with the wet chlorine gas through a heat exchanger, the temperature of the filtered salt water can generally meet the requirements for entering the resin tower in summer, thereby saving some steam as well. The disadvantage is that when the brine supply is suddenly interrupted, there is no heat exchange between the material and the wet chlorine, resulting in fluctuations in chlorine levels within the system.
It can be used to heat the filtered brine fed into the resin tower; some companies do use this approach. The heat exchanger must be of high quality, as any leakage of fluids can have serious consequences
Using the same Beihua Machinery process as the original poster, we are considering using wet chlorine gas to heat the brine; the chosen solution is a fully titanium tubular heat exchanger to be installed before the E-153 plate heat exchanger. According to theoretical calculations, this setup should be able to raise the temperature of 61.31 m3 of brine by 5°C using wet chlorine gas in quantities of 50,000 tons. It’s possible to save around 0.5 tons of steam per hour, which can be put to good use.
The idea is good, but I’m not sure what the actual results will be When wet chlorine gas passes through the plate exchanger, it is necessary to consider whether the discharge of chlorinated water is smooth; if liquid accumulates, it will inevitably cause fluctuations in the gas phase pressure of the electrolyzer, which will have some impact on production and the equipment. Therefore, I think this matter should be considered carefully...
The wet chlorine gas for heat exchange with brine solution is not widely used at present, and its reliability is low; poor drainage of chlorinated water can cause fluctuations in chlorine gas pressure or lead to automatic shutdowns. Currently, work is being done on improving the reliability of this process design
This improvement requires careful consideration, with a plan in place for how to handle any abnormalities that may arise.