2 replies to this topic

[kylene28]

Hi, is there someone here familiar with the process of crystallization? I'm doing P&ID of crystallizer and I need to know why condenser is needed and the reason why condensate needs to go back to the vessel.  Hope you can help me. Thanks.

[GSaikrishn]

dear kylene, could you please share a small sketch for better understanding. because it may so happen that all the crystallizer units may not have the same configuration. Like what is the material that is being crystallized, what is the source of refrigerant. etc..

[fseipel]

In some processes, vacuum crystallization is performed.  In this case, the slurry is concentrated by solvent evaporation.  The solvent boils, which not only concentrates the solution causing more solids to precipitate, but also cools it, decreasing the solubility of the material being crystallized.  If the solvent (reflux) is returned to crystallizer, instead of being collected  to a receiver or storage tank, it will not have the concentrating effect, but will still have the cooling effect.  The reason for doing this is that you can typically achieve much more surface area for a condenser than a cooling jacket, and you don't have to worry about forming a thick layer of cake on the sidewalls of say, a jacketed crystsallizer.  If you must use a jacket, split pipe is preferred in my opinion, especially multi-zone split pipe.