Steady-state operation analysis of an ideal heat integrated distillation column

A systematic approach for the steady-state operation analysis of chemical processes is proposed. The method affords the possibility of taking operation resilience into consideration during the stage of process design. It may serve the designer as an efficient means for the initial screening of alternative design schemes. An ideal heat integrated distillation column (HIDiC), without any reboiler or condenser attached, is studied throughout this work. It has been found that among the various variables concerned with the ideal HIDiC, feed thermal condition appears to be the only factor exerting significant influences on the interaction between the top and the bottom control loops. Maximum interaction is expected when the feed thermal condition approaches 0.5. Total number of stages and heat transfer rate are essential to the system ability of disturbance rejection. Therefore, more stages and higher heat transfer rate ought to be preferred. But, too many stages and higher heat transfer rate may increase the load of the compressor, and hence a trade-off between system resilience and energy saving has to be taken care of. Much strong interaction would be expected for the ideal HIDiC because of the high degree of structure symmetry between the rectifying and the stripping sections. However, it could still be possible to operate it smoothly with decentralized PI controllers.