Journal article
Modeling phase equilibria of alkanols with the simplified PC-SAFT equation of state and generalized pure compound parameters
Center for Phase Equilibria and Separation Processes, Department of Chemical and Biochemical Engineering, Technical University of Denmark1
Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Center for Energy Resources Engineering, Centers, Technical University of Denmark3
The simplified PC-SAFT equation of state has been applied to liquid-liquid, vapor-liquid and solid-liquid equilibria for mixtures containing 1-or 2-alkanols with alkanes, aromatic hydrocarbons, CO2 and water. For the alkanols we use generalized pure compound parameters. This means that two of the physical pure compound parameters, in (segment number) and or (segment diameter), are obtained from linear extrapolations, since m and m sigma(3), increase linearly with respect to the molar mass, and moreover, the two association parameters (association energy and association volume) were assumed to be constant for all alkanols.
Only the dispersion energy is fitted to experimental data. Thus it is possible to estimate parameters for several 1-and 2-alkanols. The final aim is to develop a group contribution approach for PC-SAFT which is suitable for complex compounds, considering that the motivation of this project is to obtain a thermodynamic model which can be used in the development of sophisticated products such as pharmaceuticals, polymers, detergents or food ingredients.
One of the severe limitations in applying SAFT-type equations of state to these compounds is that the procedure for obtaining the pure compound parameters is usually based on fitting to saturated vapor pressure and liquid density data over an extended temperature range. However, such data are rarely available for complex compounds.
To verify the new pure compound parameters, comparisons to ordinary optimized alkanol parameters, where all five pure compound parameters were fitted to experimental liquid density and vapor pressure data, were made. The results show that the new generalized alkanol parameters from this work perform at least as well as other alkanol parameter sets. (c) 2007 Elsevier B.V.
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Language: | English |
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Year: | 2007 |
Pages: | 83-94 |
ISSN: | 03783812 and 18790224 |
Types: | Journal article |
DOI: | 10.1016/j.fluid.2007.05.009 |
ORCIDs: | Kontogeorgis, Georgios and von Solms, Nicolas |
AAD; absolute average deviation AAD(%)=100/np?((Zicalcd-Ziexptl)/Zicalcd) where np is the number of data points and Z represents P or x Alkanols EoS; equation of state GC-SAFT; group contribution SAFT LLE; liquid-liquid equilibria Liquid-liquid equilibria PC-SAFT; perturbed chain-SAFT equation of state SAFT; statistical associating fluid theory SLE; solid-liquid equilibria Simplified PC-SAFT Solid-liquid equilibria VLE; vapor-liquid equilibria Vapor-liquid equilibria