Collaborative Research Center/Transregio 63

"Integrated Chemical Processes in Liquid Multiphase Systems"

>Research>Completed Projects>Project C3 E

C3 Global Optimization of Integrated Liquid Multiphase Systems (completed)

Sub-Coordinators: Jun.-Prof. Dr. Dennis Michaels, Prof. Dr.-Ing. Achim Kienle
Researcher: M.Sc. Nick Mertens

State of the art 

Determining an optimal design for the synthesis of chemical processes typically gives rise to non-convex mixed-integer nonlinear optimization problems (MINLP). A general approach for (determinis-tic) global optimization makes use of solving strong convex relaxations. In the recent past, significant progress has been made in this direction, and several software packages are nowadays available. It should, however, be noted that current state-of-the-art global optimization software is still not able to solve typical design problems as studied in this research center within a reasonable time limit. This is, in general, even true for problems that are considered to be relatively simple from an engineering point of view.

Research goals

The goal of subproject C3 is to develop new mathematical methods for the deterministic global optimization of liquid multiphase systems. The focus in the second funding period is, in particularly, on

1. Distillation-based (non-) ideal multicomponent separation processes,
2. Reaction processes with temperature controlled catalyst separation,
3. Simultaneous consideration of reaction processes and downstream processing,
4. Global optimization under uncertainty (in cooperation with subproject C1).

More information
  • Mixed-integer non-linear optimization
  • Global optimization
  • Discrete optimization
  • Application on design problems arising from chemical engineering
  • Analysis, synthesis and dynamics of integrated chemical processes (reactive distillation, chromatographic reactors, membrane reactors etc.)
  • Population balance modeling and dynamics of particulate systems (crystallization, granulation, virus infection in cell cultures)
  • Plantwide dynamics and control of chemical processes
  • Nonlinear dynamics of biological systems


Recent Publications

Keßler, T.; Kunde, C.; Mertens, N.; Michaels, D.; Kienle, A. Global optimization of distillation columns using surrogate models. SN Applied Sciences, 1,11, 2018. []

Mertens, N.; Kunde, C.; Kienle, A.; Michaels, D. Monotonic reformulation and bound tightening for global optimization of ideal multicomponent distillation columns. Optim. Eng., 19(2), 479-514, 2018. []


Keßler, T.; Mertens, N.; Kunde, C.; Nentwich, C.; Michaels, D.; Engell, S.; Kienle, A. Efficient global optimization of a novel hydroformylation process. Comput.-Aided. Chem. Eng., 40, 2113-2118, 2017. [doi: 10.1016/B978-0-444-63965-3.50354-8]

Mertens, N.; Kunde, C.; Kienle, A.; Michaels, D. Global optimization of ideal mulit-component distillation columns. Ergebnisberichte des Instituts für Angewandte Mathematik, 567, 2017. []


Kunde, C.; Michaels, D.; Micovic, J.; Lutze, P.; Górak, A.; Kienle, A. Deterministic global optimization in conceptual process design of distillation and melt crystallization. Chem. Eng. Process., 99, 132-142, 2016. [doi:10.1016/j.cep.2015.09.010]

Mertens, N.; Kunde, C.; Kienle, A.; Michaels, D. A Reformulation Strategy for Deterministic Global Optimization of Ideal Multi-component Distillation Processes. Comp. Chem. Eng., 38, 691-696, 2016. []


Ballerstein, M.; Kienle, A.; Kunde, C.; Michaels, D.; Weismantel, R. Deterministic Global Optimization of Binary Hybrid Distillation/Melt-Crystallization Processes Based on Relaxed MINLP Formulations. Optimization and Engineering,  16(2), 409-440, 2015. [doi:10.1007/s11081-014-9267-5]

Kunde, C.; Kienle, A. Deterministic Global Optimization of Multistage Melt Crystallization Processes in Hydroformylation. Comput.-Aided Chem. Eng., 37, 1061–1066, 2015. [doi:10.1016/B978-0-444-63577-8.50022-X]


Ballerstein, M. Convex relaxations for mixed-integer nonlinear programs. Eidgenössische Technische Hochschule Zürich, 2013.

Last updated:18-01-2022