Read the abstract of Prof. Gmehling's plenary lecture at ICSST 2013

Prof. Gmehling is an invited speaker at the 7th International Conference on Separation Science and Technology (ICSST) from July 2nd to July 4th 2013 in Chengdu, Sichuan, China. The abstract of his plenary lecture is as follows:



The application of predictive thermodynamic models and the Dortmund Data Bank for the synthesis and design of chemical processes - in particular separation processes.


The synthesis, design and simulation of chemical processes, in particular separation processes, is carried out by solving the resulting balance equations of a mathematical model of the considered unit operation or the whole chemical plant using commercial process simulators.

The reliability and correctness of the simulation results is mainly influenced by the reliability and correctness of the thermophysical property parameters used for the pure compounds and their mixtures. For the description of the required phase equilibria, gE-models and equations of state were developed. These models allow the calculation of the phase equilibrium behavior of multicomponent systems using binary experimental data only.

However, since the number of experimental binary data is limited, these methods often cannot be applied. Therefore in particular for process development reliable predictive models with a large range of applicability are most important.

With the help of the worldwide largest factual data bank (Dortmund Data Bank, DDB) for pure component properties, phase equilibria and excess properties, powerful group contribution methods (UNIFAC, modified UNIFAC) have been developed in my research group. By combination of cubic equations of state with the group contribution concept, as in PSRK and VTPR, even the phase equilibrium behavior with supercritical compounds can be predicted. At the same time other important properties (e.g. densities, enthalpies, heat capacities, etc.) can directly be obtained. With the development of an adequate electrolyte model (LIQUAC, LIFAC) the group contribution equation of state approach was even extended to systems with strong electrolytes. These reliable predictive thermodynamic tools with a large range of applicability in combination with factual data banks are ideal tools for the development of chemical processes.

In the lecture the status of the factual data bank and the different predictive models will be shown. Besides typical results of the predictive thermodynamic models important ap­plications of industrial interest, e.g.:

  • examination of model parameters prior to process simulation
  • determination of separation problems (azeotropic points)
  • construction of residue curves
  • selection of suitable solvents for separation processes (azeotropic and extractive distillation extraction, absorption, ..)
  • consideration of the real behavior on the chemical equilibrium conversion
  • …….

using the predictive thermodynamic models and/or the Dortmund Data Bank will be presented.

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