(341e) Process Intensification in Multicomponent Distillation

Distillation is, and continues to be, the predominant choice for separation of mixtures in chemical and petrochemical industries. Given its ubiquity and energy intensive nature, it is surprising to note that the basic distillation flowsheet for a majority of separations involving multicomponent mixtures remain almost the same for decades. However, the recent push for process intensification is driving the research towards designing novel distillation flowsheets that reduce the overall energy requirement and equipment size. In this talk, we consolidate recent advancements and present an easy-to-follow recipe for industrial practitioners to design novel intensified distillation flowsheets.

Though the term ‘process intensification’ is relatively new, a handful of intensified distillation arrangements have been reported in the literature. Well known examples include Wright’s [1] dividing wall column (DWC), Agrawal’s [2] DWC arrangements for side-rectifier and side-stripper, Brugma’s [3] configuration, Kaibel’s [4] column, etc. Nevertheless, a systematic approach to draw such arrangements is missing in the literature. Here, we discuss the following aspects of process intensification for a general zeotropic n–component distillation: (1) Improving operability of thermally coupled columns by means of eliminating vapor streams in thermal couplings with only liquid transfers or column section rearrangement; (2) double and multi-effect arrangements for thermally coupled configurations; (3) simultaneous heat and mass integration to reduce column sections and overall heat duty; (4) systematic consolidation of column shells to draw novel operable DWC configurations with shells ranging between 1 to n – 2. We demonstrate these aspects through examples and illustrate how they lead to compact, easy-to-operate, energy-efficient and cost-effective multicomponent distillation system designs.

1. Wright, R. O. Fractionation Apparatus. U.S. Patent 2,481,134, 1949.
2. Agrawal, R., 2001. Multicomponent distillation columns with partitions and multiple reboilers and condensers. Industrial & engineering chemistry research, 40(20), pp.4258-4266.
3. Johan, B.A. Process and device for fractional distillation of liquid mixtures, more particularlypetroleum. U.S. Patent 2,295,256, 1942.
4. Kaibel, G., Miller, C., Klass, K., Kindler, A., Aquila, W., Dobler, W., Breuer, K., Pommer, A. and Dirnsteiner, T., BASF SE. Dividing-wall column with feed in whole or in part in the vaporous state and/or side stream take off in whole or in part in the vaporous state. U.S. Patent 7,090,748, 2006.