High-Pressure Phase Equilibria for the Carbon Dioxide + 3-Pentanol and Carbon Dioxide + 3-Pentanol + Water Systems

Abstract

High-pressure vapor−liquid equilibria for the binary carbon dioxide + 3-petanol system were measured at 313.2 K. The phase equilibrium apparatus used in this work was of the circulation type in which the coexisting phases were recirculated, on-line sampled, and analyzed. The critical pressure and corresponding mole fraction of carbon dioxide at 313.2 K were found to be 8.22 MPa and 0.974, respectively, for this binary system. The phase equilibria for the ternary carbon dioxide + 3-pentanol + water system were also measured at 313.2 K and pressures of 2.00, 4.00, 6.00, 8.00, and 8.25 MPa. This ternary system showed the liquid−liquid−vapor (LLV) phase behavior over the range of pressure up to the critical pressure of 8.25 MPa. The binary equilibrium data were all reasonably well-correlated with the Redlich−Kwong, Soave−Redlich−Kwong, Peng−Robinson, and Patel−Teja equations of state incorporated with the eight different mixing rules: the van der Waals, Panagiotopoulos−Reid, and six modified Huron−Vidal mixing rules with UNIQUAC parameters. For the prediction of high-pressure phase equilibria for the systems containing carbon dioxide and alcohols, the SRK-MHV2 might reproduce many features of the measured behavior although further tests are needed with other systems.

Measurement and modeling of high-pressure (vapor+liquid) equilibria of (CO2+alkanol) binary systems

“…The vapor phase mole fractions showed negative differences and were <3%, also decreasing at higher pressures for the same pressure range. The measured critical point reported in Lee et al [13] was in good agreement with the value observed in this work. In general for the three (CO 2 + C 5 alcohol) systems studied in this work, the main differences with the literature were observed at low pressures (2 to 6) MPa for the vapor phase mole fraction, and they may be due to uncertainties in the gravimetric analysis used to determine phase compositions.…”

“…Additionally, data reported by Silva-Oliver et al [12] at T = 332 K were not included in figure 3, nevertheless, they showed qualitative consistence with the results of this contribution. For the system (CO 2 + 3-pentanol) at T = 313 K, and at the pressure range of (2 to 8) MPa, the differences of the liquid phase mole fractions, between this contribution and Lee et al [13] were positive and <15% near 2 MPa, decreasing significantly at higher pressures. The vapor phase mole fractions showed negative differences and were <3%, also decreasing at higher pressures for the same pressure range.…”

“…For the (CO 2 + ethanol) binary system experimental high-pressure (vapor + liquid) equilibria (VLE) data have been extensively reported at temperatures from (283 to 373) K and pressure range of (0.5 to 14.3) MPa by several authors [2,[6][7][8][9]. However, little information of the systems studied in this work was available in the literature, selected experimental information for high-pressure VLE of the three systems measured in this contribution: (CO 2 + 3-methyl-2-butanol) [10], (CO 2 + 2-pentanol) [11,12], and (CO 2 + 3-pentanol) [13], is summarized in table 1.…”

“…Critical temperatures and pressures (T c , p c ) and acentric factor (x) of the substances used in the experimental measurements[10,13,21,22].…”

Development of a Kinetic Model for Supercritical Fluids Fischer−Tropsch Synthesis

“…The primary reason for choosing the SRK EOS in this analysis is the ability of SRK EOS in predicting the phase behavior of FTS reaction mixture which has been well-demonstrated in the literature. ,, Water is one of the major FTS products; the amount of water present in the reaction mixture is relatively small compared to amounts of hydrocarbon solvent present in the system. The advantages of the Peng−Robinson EOS over SRK EOS have been demonstrated only for CO 2 - or water-rich supercritical reaction systems. , However in near critical and supercritical FTS, the reaction mixture is rich in hydrocarbon solvent(hexane) where the SRK EOS accurately represents phase behavior. The fugacity parameters and fugacity coefficients for this model represent all components in the FTS reaction mixture including reactants (CO and H 2 ) and typical products (olefins (C 2 −C 22 ), paraffins (C 1 −C 25 ), water) in addition to the solvent in SCF-FTS that has been represented by hexanes (C 6 mixture).…”