(277c) Synthesis of Distillation-Based Separation Networks Using Block Superstructure
Previously, building block superstructure  has been applied to address systematic process intensification, e.g., membrane reactors, reactive distillation systems, etc., by utilizing fundamental phenomena building blocks instead of equipment-based representation. Later on, this approach is applied to address general process synthesis and integration problems [9-11]. In this work, we apply the block-based approach for systematic synthesis of distillation networks. Block superstructure is comprised of blocks positioned on a two-dimensional structure. Interaction of blocks with material and energy flow is facilitated by the direct connecting streams between adjacent blocks and âjump connecting streamsâ among all blocks. The boundary between each block can be used to represent vapor-liquid equilibrium phenomena, or designated as completely restricted boundary indicating restriction of material flow (i.e. wall). Also this boundary can be unrestricted for achieving splitting composition requirements. With this, distillation column trays and dividing walls separating different regions of the distillation columns can be represented with multiple adjacent blocks. To achieve heat integration among all separation alternatives, each stream connecting adjacent blocks is assigned with heaters/coolers. The ensemble of these blocks leads to various type of distillation network representations. We formulate this block superstructure for distillation network synthesis as a mixed integer nonlinear programming optimization (MINLP) problem to minimize the total annual cost. The proposed model is applied to various distillation network synthesis problems, involving simple distillation sequences and heat-integrated distillation networks. Among these case studies, various type of distillation alternatives can be identified such as dividing wall columns and thermally coupled columns.
 Humphrey, Jimmy L. Separation processes: playing a critical role. Chemical Engineering Progress, 1995, 91:10.
 Demirel, S. E., Li, J., Hasan, M. M. F. Systematic process intensification using building blocks. Computers & Chemical Engineering, 2017, 105: 2â38.
 Tian, Y., Demirel, S. E., Hasan, M. M. F., Pistikopoulos, E. N. An Overview of Process Systems Engineering Approaches for Process Intensification: State of the Art. Chemical Engineering and Processing: Process Intensification, Submitted.
 Torres-Ortega, C. E., & Segovia-Hernandez, J. G. The importance of the sequential synthesis methodology in the optimal distillation sequences design. Computers & Chemical Engineering, 2014, 62: 1-9.
 Leeson, D., Fennell, P., Mac Dowell, N., & Shah, N. Simultaneous design of separation sequences and whole process energy integration. Chemical Engineering Research and Design, 2017, 125: 166-180.
 Caballero, J. A., & Grossmann, I. E. Optimal synthesis of thermally coupled distillation sequences using a novel MILP approach. Computers & Chemical Engineering, 2014, 61: 118-135.
 Madenoor Ramapriya, G., Tawarmalani, M., & Agrawal, R. A systematic method to synthesize all dividing wall columns for nâcomponent separationâPart I. AIChE Journal, 2018, 64(2): 649-659.
 Lutze, P., Gani, R., Woodley, J. M. (2010). Process intensification: a perspective on process synthesis. Chemical Engineering Processing: Process Intensification, 49(6): 547â558.
 Li, J.; Demirel, S.E.; Hasan, M.M.F. Process Synthesis using Block Superstructure with Automated Flowsheet Generation and Optimization. AIChE Journal, 2018, under review.
 Li J., Demirel S.E., Hasan M.M.F. Process Integration using Block Superstructure. Industrial & Engineering Chemistry Research, 2018, 57: 4377â4398.
 Li J., Demirel S.E., Hasan M.M.F. Fuel Gas Network Synthesis Using Block Superstructure. Processes. 2018, 6(3): 23.