Model Comparison for Thermally Coupled Distillation Columns Developed for Optimization Objectives

Distillation accounts for a significant amount of separation processes industrially used with large energy consumption. This has led to extensive work over the recent years on new column sequencing routines developed with energy and capital investment savings in mind. Based on experience thermally coupled sequences of distillation columns compared to other direct and indirect sequences can lead to 30% energy saving for three component systems. Thermally coupled column sequences require detail optimization studies as the optimum operating conditions is greatly problem dependant. For any optimization study numerous runs of the process model would be required resulting in extensive computational time and cost. Saving CPU time in a simulation can make proper optimization studies possible. Two possible simulation approaches are available. An iterative series approach solving each column independently in consecutive loops, and a parallel approach solving a single matrix only once. In this paper having developed both simulation programs a comparative study has been carried out to nominate the better approach of the two for different operation conditions.