Influence of the Objective Function on Parameter Estimation for VLE Calculation of a Binary System

Influence of the Objective Function on Parameter Estimation for VLE Calculation of a Binary System

YOUNG, A. F; PESSOA, F. L. P; AHÓN, V. R. R

Pôster:

When different objective functions are used in parameter estimation, quite different results can be obtained for the same system. In this work, to exemplify this issue, the vapor-liquid equilibrium (VLE) of the tetrachloromethane - acetic acid system was modeled with a ϕ-ϕ approach by means of EoS/G E type models. The models combine the potentialities of the Peng-Robinson cubic equation of state and the UNIQUAC local composition model through three different mixing rules: HeidemannKokal, LCVM and Wong-Sandler. The binary interaction parameters of the UNIQUAC model were estimated taking into account or not the molar fraction of both components in the vapor phase. The performance of these models was then compared with the performance of the traditional Peng-Robinson equation. The results obtained with the two objective functions were shown to be different not only quantitatively but also qualitatively. In this way, it is demonstrated that it is very important to be attentive to the choice of the objective function so that the results of the modeling could be correctly analyzed.

When different objective functions are used in parameter estimation, quite different results can be obtained for the same system. In this work, to exemplify this issue, the vapor-liquid equilibrium (VLE) of the tetrachloromethane - acetic acid system was modeled with a ϕ-ϕ approach by means of EoS/G E type models. The models combine the potentialities of the Peng-Robinson cubic equation of state and the UNIQUAC local composition model through three different mixing rules: HeidemannKokal, LCVM and Wong-Sandler. The binary interaction parameters of the UNIQUAC model were estimated taking into account or not the molar fraction of both components in the vapor phase. The performance of these models was then compared with the performance of the traditional Peng-Robinson equation. The results obtained with the two objective functions were shown to be different not only quantitatively but also qualitatively. In this way, it is demonstrated that it is very important to be attentive to the choice of the objective function so that the results of the modeling could be correctly analyzed.

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DOI: 10.5151/cobeq2018-PT.1009

Referências bibliográficas

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Como citar:

YOUNG, A. F; PESSOA, F. L. P; AHÓN, V. R. R; "Influence of the Objective Function on Parameter Estimation for VLE Calculation of a Binary System", p-3833-3836. In: . São Paulo: Blucher, 2018.
ISSN 23591757, DOI 10.5151/cobeq2018-PT.1009