During a continuous vacuum crystallization (forced circulation process) from a fermented broth, there are intense bubble formations by evaporation. These bubbles often hit a condensor and then the continuous process should be stopped. I want to set a bubble shield, like sieves or packing materials, at the upper part of the crystallizer. Do you have any advise and examples?
I am not clear about your question because you say it is under vacuum then from where the gas is coming inside the system. Is it air leaking or any other leaking point during crystallization. You have also not provided information about the crystallizing materials and method used here.
In my opinion, I am assuming your system vacuum tight then only probability is impurity or prime materials degassing from crystallization process which cannot be avoided.
Bubbling in vacuum is a common occurrence when a medium containing gas particles (also air) is involved. In your case (fermenting broth) the bubbling can be quite extreme. It’s due to the fact that in the vacuum, the smallest amount of gas trapped in the broth, will immediately expand to its maximum volume allowed by the residual pressure. Increasing the partial pressure may be an answer but it may be in contrast with a vacuum crystallization process.
An effective shield should be made of a micro-porous (or meso-porous?) material capable of physically shielding your condenser but also capable of trapping the broth spray produced by the bubbling. The actual gas emitted should not be a problem as the vacuum system itself should remove it quite effectively.
Thank you very much for replays
I'm sorry that I can't open the systems and materials bacuase of security reason.
I decide to operate the crystallizer at low pressure and tempearature.
I have experienced the same (not on large scale) during Vertical Directional Solidification of semiconductor material. But the it was reduced by increasing temperature gradient at the solid-liquid interface. The large temperature gradient helps in the reduction of gas trapping by fast flow of the latent heat from the crystallizing (solid) region to the liquid region.
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