Removal of chlorobenzene from HCl gas
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Sea friends: During the synthesis of the target product using chlorobenzene as a solvent, a large amount of HCl gas is produced as a by-product. Our idea is to absorb this HCl gas via falling film absorption and sell it as hydrochloric acid, but how can we remove the small amount of chlorobenzene carried in the gas? Are there any forum members familiar with this process? Or is anyone looking to provide a complete set of processes (equipment) that can solve this problem?
One is cryogenic cooling, and the other is adiabatic absorption and reanalysis
Cooling and separation should be a good method; the vapor pressures of the two substances are likely to differ significantly, making separation easy. There shouldn’t be any major issues with producing crude salt or acid
At cryogenic temperatures, only crude salt and acid can be produced; they cannot be sold as by-products. Adiabatic absorption reanalysis should be feasible, but I’m not sure what the specific process entails
Thank you for your guidance~~ For ordinary cooling and separation, the purity of the salt and acid produced is not sufficient to be sold as by-products. If deep condensation is used, the costs are too high. Is there any better method?~
The difference in molecular diameter and polarity between the two substances should be significant; hydrogen chloride should be more easily adsorbed, so pressure swing adsorption could be an option to consider. This requires experiments or specialized design
{:3_60:} Add a washing tower before your clean salt-acid absorption system; the amount of washing fluid required isn’t large, and the washing solution can be a salt-acid saturated solution. After absorption for a certain period, the mixture is sent to a tank for separation – chlorobenzene is returned to the previous system, while the salt and acid go back to your washing system. If the amount of chlorobenzene contained in the gas is high, add a stage using circulating water, chilled water, or cold brine. The amount of cooling required needs to be calculated by someone who specializes in such design work; I haven’t dealt with such designs before.
{:3_65:} You can also add a salt and acid buffer tank dedicated for washing, and regularly separate the chlorobenzene from it
Thank you for your participation, but what you mentioned will still introduce chlorobenzene into the salt acid; it is not possible to achieve complete removal of chlorobenzene
If the conditions permit, it is recommended to use: 1. cryogenic treatment, 2. activated carbon adsorption, 3. washing with saturated salt acid solution. 4. HCL water washing to produce salt acid.
1. Chlorobenzene can first be cooled and separated through cryogenic methods, thereby purifying hydrogen chloride. 2. The chlorobenzene contained in the hydrogen chloride gas is then adsorbed using an activated carbon tank; once adsorption reaches saturation, regeneration can be carried out