Phase Equilibria in Hydrocarbon Systems. Volumetric and Phase Behavior of the Methane-Propane System.

A re-entrant resonator for the measurement of phase boundaries: dew points for {0.4026CH4+0.5974C3H8}

“…The next most significant contribution to dp arises from dp d /dT, the slope of the dew-curve, which was estimated from a preliminary analysis of our results. At T = 330 K our results gave dp d /dT % 0.15 MPa AE K À1 and this resulted in an additional contribution to the uncertainty dp between (0.0065 and 0.012) MPa {for k = 2 (0.013 and 0.024) MPa} that was also included in the uncertainty listed in table 1; at T % 320 K and x % 0.4 the results reported in [9] gave dp d /dT % 0.10 MPa AE K À1 while at T % 339 K we estimated from an equation of state dp d /dT % 0.30 MPa AE K À1 . The dew pressures were estimated for {0.4026CH 4 + 0.…”

“…23 2.871 ± 0.026 uncertainties, listed in table 1 at a confidence of 0.995 (k = 2), for the phase boundary temperature and pressure were obtained by combining in quadrature uncertainties arising from the determination of the phase boundary location (that is 0.25 times the step size) with uncertainties arising from dT/dx, dp/dx, dp d /dT, and the individual measurements of temperature, pressure and frequency. The contribution to the uncertainty arising from the uncertainty in composition was estimated from the phase border measurements reported by Reamer et al [9] that give dT/dx % À81 K while dp/dx % 8.4…”

“…The p d predicted by NIST14 differ from PR SPECS by between 0.67 and 0.96 % while both SRK estimates lie 0.4 % above at T = 315 K and these differences diverge from PR SPECS and our results to be À2.5 % at T = 337 K that is about a factor of 5 greater than the estimated expanded uncertainty of our measurements. To our knowledge, there are only eight publications [8][9][10][11][12][13][14][15] that report the dew pressure of {(1 À x)CH 4 + xC 3 H 8 } as a function of (1 À x) at temperatures in the range (273 to 363) K and all are shown in figure 7 with those listed in table 1. The results reported by May et al [14], from measurements with a dual-sinker densimeter, and those of May et al [15], with a version of the re-entrant cavity optimised to determine ratio of the gas-to-liquid volume within the two-phase region, are both for (1 À x) > 0.75 and cannot be compared directly with our results.…”

“…The operation of the re-entrant cavity is demonstrated with measurements of the dew pressure for {0.4026CH 4 + 0.5974C 3 H 8 } at temperatures in the range (315 to 340) K. There are eight publications [8][9][10][11][12][13][14][15] that report the phase behaviour of {(1 À x)CH 4 + xC 3 H 8 } at temperatures in the range (273 to 363) K. References [8][9][10][11][12][13] report results obtained from (p, V, T, x) measurements, while [14] reports dew pressures obtained with a dual-sinker densimeter. May et al [15] used a re-entrant cavity modified to optimise the determination of liquid drop-out-volume with a resonance at frequencies of GHz.…”

Calculation of vapor–liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part III. Extension to water–light hydrocarbons systems

“…CH 4 -C 2 H 6 system Gomes de Azevedo and Calado (1989) 90-104 0.03-0.51 15 Wichterle and Kobayashi (1972a) 130-200 0.01-52 135 Davalos et al (1976) 250 13-66 8 Gupta et al (1980) 260-280 17-71 52 Wei et al (1995) 210-270 3-65 54 CH 4 -C 3 H 8 system Wichterle and Kobayashi (1972b) 130-213 2-65 105 Reamer et al (1950) 277-361 7-102 128 Akers et al (1954) 158-273 3-100 81 Sage et al (1934) 293-363 10-96 55 CH 4 -nC 4 H 10 system Sage et al (1940) 294-394 2-132 124 Roberts et al (1962) 211-411 2-132 83 Wiese et al (1970) 278-378 14-133 25 Chen et al (1974) 144-278 1-129 173 Kahre (1974) 166-283 1-110 71 CH 4 -CO 2 system Donnelly and Katz (1954) 200-271 11-79 110 Kaminishi et al (1968) 233-273 37-82 14 Arai et al (1971) 253-288 26-85 28 Davalos et al (1976) 230-270 9-86 34 Mraw et al (1978) 153-219 7-65 51 Neumann and Walch (1968) 173-220 27-69 64 Al-Sahhaf et al (1983) 219-270 9-84 32 Xu et al (1992) 288-293 57-82 21 Wei et al (1995) 230-270 11-84 49 H 2 O-CH 4 system at temperatures between 600 and 647.2 K (the critical temperature of water), but it is beyond the scope of this paper. Among the experimental data for the vapor-liquid equilibria of the H 2 O-C 2 H 6 system, the ethane solubility data measured by and the water content data measured by Reamer et al (1943) and Yarrison et al (2006) cover larger P-T range.…”