How reflux works
by Paul Morehead
In a distillation column, a liquid reflux is introduced near the top of the column to clean the upflowing vapor. This stream has a high concentration of the light key component and is often nearly pure.
As the reflux flows down the column, a disequilibrium exists between the reflux and the upflowing vapor. As a result, heavy compounds leave the upflowing vapor and enter the clean reflux. The upflowing vapor becomes progressively more pure, i.e., less tainted with the heavy key.
Just as clean water is used to remove dirt from hands, so is liquid reflux used to remove heavy compounds from the upflowing vapor.
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