From kiva Tue Jan 14 13:20:36 1997

Hello,
This is the title and the abstract of my presentation on
PROST-seminar.
The aim of this report is to present the problem under my study now
for the discussion.

   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.

Regards,
Valeri