Three-phase liquid-liquid-vapor equilibria in the binary systems nitrogen + ethane and nitrogen + propane

Abstract

The phase equllibria behavior of the binary mixtures nitrogen + ethane and nitrogen + propane Is studied along their three-phase liquid-liquid-vapor loci at temperatures greater than 117 K. Data presented are pressure, and L, and L, Ilquld-phase compositions and molar volumes as a function of temperature. Comparisons with literature data are made. IntroductlonWe have undertaken an extensive study of liquid-liquid-vapor (L,-L,-V) phenomena in well-defined ternary prototype systems of liquefied natural gas (LNG) (7-6). Many of these ternary systems have exhibited L-L-V immiscibility without having an immiscible constituent binary pair. An example would be the system methane + ethane + n-octane (7), whose three-phase thermodynamic phase space is bounded by loci of K points [L,-L, = V), LCST points (L, = L,-V), and Q points (S-L,-L,-V).By comparison, the systems methane + n-hexane + n-octane (3) and methane + n-hexane + nitrogen ( 5 ) had a constituent binary pair, methane + n-hexane, which exhibited L-Density measurements of the molten CoC1,-KCI mixtures of hlgh CoCI, composith wlth an open vessel are very dlfflcult or aknost ImpOedMe because of their hlgh volatility. The densities of CoCl, and KCI mixtures sealed In a quartz cell have been measured by a dllatometrlc method. The excess molar volume was posltlve around 30 mol % and around 70 mol % of CoC4. The results of the present lnvestlgatlon suggested that the tltle system contains the tetrahedral conttguration, CoC1,2-, at the composition X(CoC1,) = 0.30 and the other unknown species at X(CoC1,) = 0.70.

Solubility of Nitrogen in Methane, Ethane, and Mixtures of Methane and Ethane at Titan-Like Conditions: A Molecular Dynamics Study

“…Cassini’s Radio Detection and Ranging (RADAR) observations further suggested transient bright features on the second largest hydrocarbon sea, Ligeia Mare, known as “Magic Islands”. , Hofgartner et al have argued that these features could not be image artifacts or permanent geophysical structures but are consistent with ephemeral phenomena, such as suspended solids, bubbles, waves, and tides on Titan . Using a numerical model and existing solubility data of nitrogen in methane and ethane, , Cordier et al have hypothesized that these transient bright features may correspond to exsolution of nitrogen, giving rise to large nitrogen bubbles detected as bright objects by Cassini’s RADAR. Motivated by this, laboratory measurements of solubility of nitrogen in liquid methane, ethane, and mixtures of methane and ethane, the primary components of seas and lakes on Titan, have been carried out. , They find that the solubility of nitrogen in methane is much larger compared to ethane.…”

Use of ab initio interaction energies for the prediction of phase equilibria in the system nitrogen–ethane

“…Predictions of the high-pressure VLE and VLLE have been made using the Soave-Redlich-Kwong equation of state (SRK-EOS) with ab initio-NRTL and ab initio-UNIQUAC in the PSRK-mixing rule. 7 The deviations of the calculated pressures from measurements [8][9][10][11][12][13][14][15][16][17] Dp…”

Phase Behavior Prediction and Modeling of LNG Systems with EoSs - What is Easy and What is Difficult?

“…P-T space of the boundaries of the three-phase L 1 -L 2 -V regions for the system nitrogen + methane + ethane. Experimental data from Llave et al (1985Llave et al ( , 1987. Llave et al (1987).…”