Velkommen til aarets foerste PROST-seminar:
Foredragshoder: Valeri Kiva, Karpov Institute of Physical Chemistry, Moscow
Tittel: Batch Distillation at Finite Reflux Ratio: Approach to Prediction
Abstract: Se vedlegg. Se ogsaa: http://www.kjemi.unit.no:80/prost/seminars.html
Sted: Kjemiteknikk - Lunchrommet (som vanlig)
Tid: Onsdag 22/1 kl. 13.00. Foredraget starter kl. 13.30.
Hilsen,
Frode Martinsen
[ text/plain ] :
Batch Distillation at Finite Reflux Ratio: Approach to Prediction
Abstract
Batch distillation is one of the most widely used separation
operations in the small-scale chemical industry. It is well-known
that non-ideality and especially azeptropy of the mixtures hinders
its separation. We need a method to predict the feasible product
sequences early in the design process to save time and resousces.
It was proclaimed that the product sequence for rectifier or
stripper can be predicted by using analysis of residue curve map
of the simple distillation. The method of prediction is quite
simple and visual, however, it is based on the assumption of the
infinite reflux (reboil) ratio and an infinite number of
trays. Validity of this prediction at the finite reflux (reboil)
ratios is open to question.
We propose the new approach to predict the sequence of products
and cuts at finite reflux (reboil) ratios. This approach is based
on some ideas presented in Russian literature of 70s.
Using the information about the phase portrait of distillation
lines we find the still composition sets from which certain
product compositions can be obtained at all values of reflux
(reboil) ratio and then determine the structure of the diagram of
isoreflux (isoreboil) lines for various separations. For any given
reflux (reboil) ratio these isolines split the still composition
triangle into the regions of different product composition and
define the course of the still and the product composition change
lines.
The prediction of the isoreflux line diagram and of batch
distillation lines was made for the ternary mixtures of different
type with one simple distillation region. Prognosis was proved by
the simulation of the batch distillation process, a good agreement
is shown.
The comparison of results with the prognosis based on the infinite
reflux ratio shows that proposed approach gives more correct
prediction of the feasible separations.