ANALYSIS OF ENTROPY PRODUCTION-RATES FOR DESIGN OF DISTILLATION-COLUMNS

The entropy production rate for a distillation column is at a minimum when the driving forces for separation are uniformly distributed along the column. This theoretical result was derived for separation of bin ary mixtures having linear flux-force relations with coefficients whic h vary with temperature and composition. The entropy production rate w as first calculated numerically for separation of an ideal and a nonid eal mixture. The application of the principle, called the principle of equipartition of forces, was then demonstrated by analyzing the effec t of distributed heating in a column with an ideal mixture. A reductio n in the entropy production rate per m(3) of product formed of up to 7 % was found for the system plus surroundings, after seeking equipartit ion of forces with minimum changes in the apparatus.