The UNIFAC Consortium was founded at the
Carl von Ossietzky University of Oldenburg
The Carl von Ossietzky University of Oldenburg (german: Carl von Ossietzky Universität Oldenburg) is a university located in Oldenburg, Germany. It is one of the most important and highly regarded educational facilities in northwestern Germany ...
at the chair of industrial chemistry of Prof.
Gmehling to invite private companies to support the further development of the
group-contribution methods
UNIFAC and its successor modified UNIFAC (Dortmund). Both models are used for the prediction of thermodynamic properties, especially the estimation of phase equilibria.
The UNIFAC consortium is a successful example of private sponsorship of a public university in Germany.
History
The consortium was founded in 1997 when the public financing of the further development of the models became unlikely. The models UNIFAC and mod. UNIFAC (Dortmund) have already been used widely in software for the
simulation
A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the ...
and synthesis of chemical processes. Many companies doing process development in the field of
chemical engineering
Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials in ...
had announced their support for a new way to subsidize the further development. This is facilitated through the support of over 40 companies, and is particularly aided by the DDBST GmbH, which supplies the complete
Dortmund Data Bank
The Dortmund Data Bank (short DDB) is a factual data bank for thermodynamic and thermophysical data. Its main usage is the data supply for process simulation where experimental data are the basis for the design, analysis, synthesis, and optimizat ...
(DDB) and several software tools for free. The DDB, a factual data bank for
thermodynamic
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of t ...
data, especially
phase equilibrium data, is the main source for the work of the consortium.
Objectives
The normal work of the consortium includes
* the creation of new and the improvement of older model parameters
* the measurement of experimental data (partly own work, partly given to contractors)
* holding annual member meetings
The consortium has e. g. added or modified 404 interaction parameters in the original UNIFAC matrix compared to the 635 parameters from the latest publication.
Image:UNIFAC_Parameter_Matrix_Published.PNG, Latest published parameters
Image:UNIFAC_Parameter_Matrix_Consortium_2008.PNG, UNIFAC consortium parameters September 2008
Image:UNIFAC_Parameter_Matrix_New_or_Changed_in_Consortium_2008.PNG, In the UNIFAC consortium added or modified parameters
The major goals are to
* improve the quality of the predictions
* extend the range of applicability of the models. This include the support for further component types with new functional groups.
* supply the parameters to process simulation and DDB software (for consortium members only)
The model parameters are confidential and only accessible to consortium members for at least two and a half year after the first delivery. After this time the university can publish the model parameters.
Supported models
The UNIFAC consortium supports the development of three different models,
* original UNIFAC,
* mod. UNIFAC (Dortmund), and,
*
PSRK[Holderbaum T., Gmehling J., "PSRK: A Group-Contribution Equation of State based on UNIFAC", Fluid Phase Equilib., 70, 251-265, 1991] (since 2005).
Both UNIFAC models are estimating
activity coefficient
In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (o ...
s, PSRK (short for Predictive Soave-Redlich-Kwong) however is a combination of the original UNIFAC model with an
equation of state
In physics, chemistry, and thermodynamics, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or intern ...
.
External links
Official web site
References
Thermodynamic models