How can hydrochloric acid be deeply desorbed to below 1%?
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Dear sea friends, I read in the magazine \"Polyvinyl Chloride\" that Nantong Xingqiu’s fully automatic deep desorption system for hydrochloric acid (as advertised) can reduce the concentration of hydrochloric acid to below 1%. As far as I know, hydrochloric acid forms an azeotrope with water at 20.24%, and it is not possible to remove more hydrochloric acid using conventional desorption methods. May I ask: what is the principle behind this? Furthermore, many manufacturers set the target concentration of hydrochloric acid after desorption at 19%-21%. As mentioned earlier, hydrochloric acid forms an azeotrope with water at 20.24%; so how can the concentration be reduced to 19%?
That's how it is. If it is just simple heating to separate water and HCL. So HCL can only reach around 20%. Even if you continue to heat it up, there will be no positive effect. This is regular parsing. In zero resolution, we add calcium chloride, which absorbs water. Under conditions of high calcium chloride concentration, water is not easily vaporized, allowing HCl to be vaporized further. It should be noted, however, that with high concentrations of calcium chloride, if the temperature drops accidentally, crystallization can easily occur and block the pipes. Personally, I think the technology is fairly mature; however, zero-resolution processing imposes certain requirements on the equipment (D% \+ A1 i2 z), it also demands high levels of skill from the operators, and the staff in charge need to worry a lot as well. ======================================================================== I just found it in another post, answered by mtkevingarnett; the original post address is: http://bbs.hcbbs.com/thread-845241-1-5.html. But I still don’t understand how a conventional analysis concentration can reach 19%
Bro, for a detailed analysis, you can check previous posts; our company has been using it for 2 years now. . . . . We can communicate. . . . .
Could you please tell us about the effects of using it? Our company uses conventional analysis; as mentioned in the previous response, in-depth analysis causes significant wear and tear on the equipment, especially on pumps. Could you provide some details on this? Thank you. . .
You mean in-depth analysis! The principle relies on the strong water-absorbing capacity of high-concentration calcium chloride to remove the water from hydrochloric acid! This is a patented technology from Capon Roland! The pressure resistance of graphite equipment must be quite high!
1. Due to the high temperature throughout the system, special attention must be paid when selecting gaskets； 2. The in-depth analysis uses conventional analysis methods, with calcium chloride added as an anti-boiling agent; communication is carried out with the manufacturer to determine the process flow, equipment locations, and elevations ； 3. Due to the high temperatures, graphite pumps are generally chosen; however, they are not recommended as they tend to get damaged easily. It is advised to consult with pump manufacturers to select other high-temperature resistant pumps ； 4. The current processing capacity is 1.2 m3/h, with the acid concentration in the water being around 1%.
The hydrochloric acid resolution process system is divided into conventional resolution and zero-resolution. The conventional decomposition [1] process is the reverse of HCl absorption; its principle involves the transfer of the solute (HCl) from the liquid phase to the gas phase, separating the solution after absorption to regenerate the solvent, and obtaining the recovered solute. When the actual partial pressure of the solute in the gas phase is lower than the equilibrium partial pressure of the solute in the liquid phase, the solute transfers from the liquid phase to the gas phase ； At standard atmospheric pressure, the azeotopic temperature of the hydrochloric acid-water system is 109°C, and the mass fraction of HCl in the azeotic mixture is 20.24%. Therefore, this method can be used to separate hydrochloric acid with a concentration higher than 20.24% into hydrogen chloride. The principle and process of zero-analysis involve mixing dilute hydrochloric acid, with a conventional analysis-quality fraction of 20.24%, with a calcium chloride solution of certain concentration in a cracking tower under medium pressure and high temperature. The high-temperature HCl, heated by a reboiler, comes into continuous contact with water vapor and calcium chloride through counter-current mass transfer and heat transfer; under specific temperature and pressure conditions, the azeotrope point of the dilute hydrochloric acid is broken. Hydrochloric acid and calcium chloride descend along the surface of the packing due to gravity, coming into contact with the rising gases, thereby increasing the HCl content in those gases. At the top of the tower, HCl gas containing saturated water is obtained; after being cooled in a condenser, this gas, with a volume fraction of 99.9% and a temperature of 40°C, is sent to the synthesis system. The wastewater generated, with a concentration of approximately 0.55%, is sent to a water-alkali washing system for the absorption of hydrogen chloride gas ； Our company has been operating the modified hydrochloric acid resolution unit for 2 years, with good performance.
Thank you. I’ve never come across this technology before; even after reading it twice, I still don’t fully understand it. Could you please send me a PID diagram along with a diagram of the equipment?
Thank you for your reply; I’ll get back to you once I understand it. . . Oh, could you share your family’s PID chart? :P
liusj506 (No. 675494): How can the problems associated with calcium chloride crystals be avoided and resolved? Can calcium ions in water affect the water alkaline cleaning system?
Will the purified water returning to the purification system have an impact on the evolution system?