Experimental simulation of distillation concentration profiles using batch apparatus: Column stripping section

It has been shown that distillation column rectifying profiles can be measured experimentally in a batch boiling apparatus using a combination of equilibrium boiling, vapour removal and the addition of material of the distillate composition (Chemical Engineering Science, 2003, 58, 479). The problem of using this concept for stripping profiles is that in order to follow the concentration profiles one needs to remove material of the bottom composition while retaining equilibrium boiling conditions. This cannot be effectively implemented as the bottoms composition is not produced in the apparatus and that the removal of this material would not be possible under equilibrium conditions.In this paper, we re-examine the differential description of the distillation stripping section and using vector concepts show that the removal of material of the bottoms compositions is equivalent to the addition of material of a composition that varies in a mathematically predictable manner with time.This feed policy has been implemented experimentally and it is shown that stripping section profiles can be measured with reasonable accuracy in a batch still. This work verifies and validates experimentally the concept that separation and mixing are opposite vectors phenomena (On the behaviour of reactive distillation systems. Ph. D. Thesis Norwegian University of Science and Technology, Trondheim.) and also offers an opportunity to combine computer software and experimental simulation to simplify troublesome calculations and help reduce computational time.