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I am having trouble understanding the difference between a recycled and refluxed stream for the distillation process. If anyone could explain in quick detail what the differences are, I would appreciate it.

[Art Montemayor]

Bucket:

In normal distillation terms, a recycle stream is one that is returned back to the distillation column (or train) in order to "re-distill" it - so to speak.

A reflux stream, on the other hand, is a nessity or a requirement of the distillation column. It constitutes a means of establishing an equilibrium at the top of the column (just below the overhead vapor outlet) such that the purity of the overhead vapor is set. The reflux liquid returned (or "recycled") to the top of the column (usually as a portion of the total overheads condensed vapor product) serves as the liquid that sets the purity level on the top tray. The relux stream is a recycle stream, but it is not recycled for the sake of re-distilling it; rather it is recycled for the purpose of setting the purity of the overheads product. It is a requirement - not an option.

I hope this serves to help you understand the two terms.