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Modeling Binary perfluoroalkane + alkane mixtures belong to the type II phase behavior in the classification of Konynenburg and Scott (1990), characterized by a continuous vapor- liquid critical line and the presence of liquid-liquid phase separation, when the difference in chain length between the two components is not very large (symmetric or close to symmetric systems). Because of the nonideal interactions in these mixtures, the unlike energy parameter was treated as adjustable, and it was set at the optimum value ξ = 0.9146 for the correct prediction of the experimental azeotrope of the perfluoro-n- hexane + n-hexane mixture at 298.15 K. The unlike size parameter was not adjusted (η = 1), because it was verified that the simple Lorentz combination rule provided satisfactory results. It is important to notice that the value of the unlike energy parameter agrees well with the values found by other authors using different models to describe these systems. In a transferable manner, the same optimized energy parameter value was used to predict the rest of the mixtures at different thermodynamic conditions. Composition diagrams of binary mixtures of perfluoro-n-hexane + n-alkane from (C5 - C8) and of n-hexane + n-perfluoroalkane from (C5 - C8) modeled in this work are presented in Figures III.25 and III.26, respectively. Figure III.27 and III.28 depicts P-x-y diagrams of the systems shown in Figure III.25 and III.26. Very good agreement is obtained between soft-SAFT predictions and experimental data in all cases, considering that the average uncertainty of the experimental compositions is 4%. In all cases the azeotropic point is correctly predicted and deviations from experimental data are lower than 5%, except in the case of the perfluoro-n-hexane + octane mixture. According to the authors (Duce et al., 2002), at 313.15 K the mixture was not completely miscible in the entire studied composition range and for perfluorohexane mole fractions between 0.189 and 0.709 they obtained demixed mixtures indicating that they were very close to a liquidliquid region as predicted in fact by the soft-SAFT EoS (Figure III.25b). The UCST calculated by the authors for this mixture is 324 K. - 155 -
y C6F14 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 x C6F14 Modeling Figure III.25. Vapor-phase mole fraction versus the liquid mole fraction for n-perfluorohexane + n-alkane mixtures: n = 5 at 293.65 K (circles), n = 6 at 298.15 K (squares), n = 7 at 317.65 K (diamonds), and n = 8 at 313.15 K (triangles). Symbols represent experimental data (Duce et al., 2002) and lines correspond to the predictions from the soft-SAFT EoS. y C6H14 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 x C6H14 Figure III.26. Vapor-phase mole fraction versus the liquid mole fraction for n-hexane + n- perfluoroalkane mixtures: n = 5 at 293.15 K (circles), n = 6 at 298.15 K (squares), n = 7 at 303.15 K (diamonds), and n = 8 at 313.15 K (triangles). Symbols represent experimental data (Duce et al., 2002) and lines correspond to the predictions from the soft-SAFT EOS. - 156 -
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Ana Maria Antunes Dias Universidade
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o júri presidente Prof. Dr. Joaqui
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palavras-chave resumo perfluoroalca
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Contents Notation List of Tables Li
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Notation Abbreviations AAD EoS LCST
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List of Tables Table I.1 Average Bo
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Table III.6 Adjusted Binary Paramet
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Figure II.9 Comparison between corr
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Figure III.8 Temperature-density di
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Figure III.25 Vapor-phase mole frac
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I.1. Fluorine Properties General In
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Table I.2. Physicochemical Properti
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General Introduction order to compa
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General Introduction the numerous a
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General Introduction carbon dioxide
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General Introduction animals. That
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General Introduction Table I.3. Lit
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References General Introduction Ban
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General Introduction Hildebrand, J.
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General Introduction Rowinsky EK. N
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II. Part EXPERIMENTAL METHODS, RESU
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Experimental Methods, Results and D
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Table II.3. (continued) T K ρexp g
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ρ / g.cm-3 1.750 1.730 1.710 1.690
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I. 3. Vapour pressure I.3.1. Biblio
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I.3.2. Apparatus and Procedure Expe
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I.3.3. Experimental Results and Dis
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Table II.8. (continued) T K Pexp kP
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ΔH vap = TΔS vap 2⎛ d ln P ⎞
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I.4. Solubility at atmospheric pres
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x2 (T,P2) 7.0E-03 6.0E-03 5.0E-03 4
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L 2,1 0.70 0.60 0.50 0.40 0.30 285
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P / MPa 6 5 4 3 2 1 0 P / MPa 14 12
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II.6. Liquid - Liquid Equilibrium I
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0 τ β Δ1 2Δ1 [ 1+ B τ + B τ +
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References Experimental Methods, Re
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III.1. Introduction Modeling Most c
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Modeling The pioneering work of Wer
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III.2. Soft-SAFT Model Modeling A S
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Modeling The equation of state is w
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Chain Term Modeling Originally Wert
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Modeling The model is easily extend
Page 123 and 124: ( ) ( ) ∑∑∑ 3 2 2 2 2 qq 32π
Page 125 and 126: Modeling HRT is a promising theory,
Page 127 and 128: ( ρ) ρ , 0 ≤ ρ ( ρ) 2 Modelin
Page 129 and 130: III.3. Application to Pure Compound
Page 131 and 132: Modeling From the optimised paramet
Page 133 and 134: T / K 400 350 300 250 200 150 100 5
Page 135 and 136: ln Pvap 1.0E+01 1.0E+00 1.0E-01 1.0
Page 137 and 138: Modeling Table III.2. Absolute Aver
Page 139 and 140: Modeling The correlation coefficien
Page 141 and 142: Pvap (MPa) 4.00 3.50 3.00 2.50 2.00
Page 143 and 144: Modeling The mixture parameters a a
Page 145 and 146: Modeling the assumptions made by th
Page 147 and 148: Modeling between oxygen and perfluo
Page 149 and 150: xSolute 5.5E-03 5.0E-03 4.5E-03 4.0
Page 151 and 152: Modeling previous work, dealing wit
Page 153 and 154: Modeling These results confirm that
Page 155 and 156: Modeling CO2 binary mixtures using
Page 157 and 158: Modeling average deviation (AAD) be
Page 159 and 160: P / MPa 14 12 10 8 6 4 2 0 0 0.2 0.
Page 161 and 162: Modeling Figures III.16, III.17 and
Page 163 and 164: Modeling calculations from the orig
Page 165 and 166: Table III.9. References for VLE exp
Page 167 and 168: P / MPa 20 18 16 14 12 10 8 6 4 2 0
Page 169 and 170: Modeling Finally, Figure III.24 pre
Page 171 and 172: III.4.4. VLE and LLE of Alkane and
Page 173: Modeling number of perfluro-n-alkan
Page 177 and 178: P / MPa 0.08 0.07 0.06 0.05 0.04 0.
Page 179 and 180: P / MPa 0.12 0.10 0.08 0.06 0.04 0.
Page 181 and 182: Modeling approach based on the meth
Page 183 and 184: Modeling Blas, F. J.; Vega, L. F.,
Page 185 and 186: DIPPR, Thermophysical Properties Da
Page 187 and 188: Modeling Hildebrand, J. H.; Fisher,
Page 189 and 190: Modeling McCabe, C.; Jackson, SAFT-
Page 191 and 192: Modeling Poling, B.; Prauznitz, J.;
Page 193 and 194: Modeling Wertheim, M. S., Fluids wi
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