STRATEGIES FOR HANDLING MIXTURES IN MULTICOMPONENT BATCH DISTILLATIONS WITH SLOP RECYCLE

A methodology is presented for determining the optimal strategy for a production campaign of several multicomponent batch distillations, inv olving several mixtures having the same components but with different compositions and allowing for the recycling of slop cuts. The methodol ogy involves the construction of a superstructure taking into account all the possible alternatives for handling of different mixtures and t he slop cuts obtained. The corresponding mathematical formulation lead s to NLP problems which are solved using available optimisation softwa re. The decision variables corresponding to this production campaign a re the proportions of each initial mixture and each slop cut introduce d into the reboiler at each batch together with the reflux ratios. A s eries of four problems shows the effectiveness of this procedure. Slop cut recycling allows significant gains in some cases. The optimal str ategy depends on the economic value of the different products.