Heat exchange between chlorine gas and secondary brine
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This post was last edited by sunjl1981 on 2013-1-6 at 19:56. The original process design for our electrolysis workshop included a heat exchanger between chlorine gas and the secondary brine; the chlorine gas needed to be cooled while the brine needed to be heated, and exchanging heat between them worked well for this purpose. Later, perhaps due to considerations regarding installation progress or the cost of heat exchangers, this design element was not adopted, after all a heat exchanger made of titanium is required. I would like to ask if there are any manufacturers that use this design How effective is it? hcbbs hcbbs
All four electrolysis units in our company use this process. It is possible to calculate how many years it will take for the cost of the titanium cooler to be recouped (through savings on steam costs). It can also reduce the heat exchange load on the scrubber tower.
Is the cathode cooled by hydrogen and circulating alkali? All that’s needed is to modify the hydrogen pipeline; there’s no need to change the heat exchanger either. However, it’s likely that an additional heat exchanger will be required, as hydrogen isn’t available during operation, and steam is still needed.
Circulating alkali heating is not commonly used during startup, right, while brine needs to be heated continuously. Here, during winter when we are operating at full capacity, there is no need to heat the circulating alkali; in other seasons, however, circulating water is definitely required for cooling.
We’ve been heating all along! For those of us in the chlorine engineering field, heating is always required; the DCS setpoint for the temperature of the circulating alkali is between 93 and 94 degrees, while the temperature of the electrolytic cell is between 87 and 88 degrees under full-load operation.
Mm-hm. A temperature of 93 to 94°C might be a bit high; hydrogen itself is around 90 degrees, and the heat exchanged isn’t sufficient to heat the base to such a high temperature. The temperature requirement for saltwater is much lower, around 60°C.
We have had this heat exchange equipment for some time; it works well for exchanging heat between saltwater and chlorine, but not effectively for exchanging heat between alkali solution and hydrogen, so its use is not recommended.
I would like to ask about the amount of chlorine produced as a result of heat exchange between brine and chlorine, as well as by how many degrees the temperature of the brine can increase
We considered this option at the time as well, but later found that the heat exchanger was expensive and difficult to maintain, so we did not go with it. We use the by-product steam generated by the synthesis furnace to power the entire caustic soda production facility; only a small amount is supplemented from the external steam network when it is not sufficient, so the actual steam consumption is not high.
The brine flow rate is approximately 100 m³/h, the production capacity is around 100,000 tons, and the brine temperature varies between 6-10 degrees depending on the season℃
It can be used. However, the effect of temperature increase varies slightly depending on the different cell systems. Chlorine produced in the tanks of chlorine production plants achieves a better temperature rise when used to heat brine.