SYNTHESIS OF FLEXIBLE THERMALLY INTEGRATED DISTILLATION SEQUENCES

A method has been developed to synthesize thermally integrated distillation sequences under conditions of uncertainty. The method minimizes the expected annual cost of the sequence and guarantees feasible operation over the entire uncertain parameter space by using an approach termed 'practical feasibility'. Results are presented which show the effect of uncertainty in feed flowrate, stage efficiency, K-value and heat transfer coefficient on sequence cost and structure for a 5 component light alkane system. The inclusion of uncertainty significantly reduces the cost savings accrued through heat integration because of the increased size of trim reboilers and condensers included to guarantee flexibility.