How to transform and recycle hydrogen chloride exhaust gas
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This post was last edited by sunjl1981 on 2013-1-6 at 20:10. At present, our factory generates a large amount of hydrogen chloride exhaust gas in the hydrochloric acid electrolysis section, and an absorption tower (using alkaline solution as the neutralizing agent) is used to treat this hydrogen chloride exhaust gas. Could some expert advise on whether it’s possible to modify the system so that water is used to absorb this hydrogen chloride exhaust gas, thereby allowing it to be recycled? # ， ， &
★I believe the absorption unit should consist of two stages in series: the first stage can use water for absorption, with water being produced as a byproduct, while the second stage uses an alkali to destroy the hydrogen chloride gas that has not been absorbed. ★95% of the hydrogen chloride gas is used to produce by-product hydrochloric acid through a recovery unit, while the remaining 5% enters an alkali absorption tower via flues for destruction; an ammonia spraying device is installed behind the alkali absorption tower. This post was last edited by yzhms on 2009-3-6 22:32]
1. Absorption should be no problem; you can refer to the moderator’s suggestions. 2. It is recommended to move the post to the chlor-alkali forum, where there are many experts in this field. This post was last edited by yzhms on 2009-3-6 at 22:31.]
1. The absorption of hydrochloric acid occurs in two ways: isothermal absorption and adiabatic absorption; it’s not clear which one the original poster is referring to； 2. Based on the poster’s question, it is assumed here that adiabatic absorption is involved; based on current production experience, water can be used for absorption, although its efficiency is lower than that of alkaline solutions ； 3. It is recommended to use water for absorption first, followed by an alkaline solution, in order to ensure air quality and increase the amount of hydrogen chloride that can be recovered ； 4. When considering the absorption tower, appropriately increase the packing arrangement to improve the initial absorption efficiency, thereby reducing the amount of exhaust gas first.
It might be a problem with the manufacturing process; could you share the details? The hydrochloric acid synthesis units provided by our company to our customers typically use two-stage falling film absorption along with one stage of packed-bed absorption; as a result, the concentration of HCl in the exhaust gas is below 10 PPm, which fully meets **environmental regulations. For further communication, please call: :call: 13962096400 :handshake b13962096400@126.COM This post was last edited by yzhms on 2009-3-8 00:20 ]
It can be completely transformed. The key issue is that it’s not known what shape the existing absorption tower has, what its diameter and height are, how much exhaust gas it can handle per day, and what the hydrogen chloride content in the exhaust gas is What material is the tower made of? Is it a packed tower or a plate tower, and what kind of packing is used? If you provide these parameters, people can offer you some advice. Regarding the process route, what was said earlier is quite accurate. First, a packed tower is used to absorb hydrogen chloride with water, and then an absorption tower employs an alkaline solution for absorption (this tower can be designed simply). The first packed tower can be made of fiberglass or other acid-resistant materials; two stages of spraying are used, and ceramic packing is the best choice.
Ceramic fillers are fragile during use, so other materials are being considered; currently, we are using different Saddle ring. Durable and long-lasting.
I think it’s entirely possible to use water to absorb hydrogen chloride and then carry out electrolysis again. Moreover, this hydrochloric acid has a high chlorine content, making regenerative electrolysis suitable. Not many companies in China produce hydrogen chloride by electrolyzing hydrochloric acid; are you conducting experiments? Large-scale production can use the existing absorption equipment for hydrochloric acid production; testing will be considered separately.
Could anyone provide some calculation examples for HCl absorption? For example, knowing the gas flow rate, HCl content, and temperature, along with the remaining calculation steps
Study Chemical Engineering Principles and Physical Chemistry thoroughly!