Observations on the multiphase equilibria behavior of CO2-rich and ethane-rich mixtures

The application of a shear mode piezoelectric sensor to monitoring the high-pressure phase behaviour of asymmetric binary systems

“…The heptane + CO 2 system has been studied in the literature over a wide temperature and pressure region [48][49][50][51][52][53]. The experimental results have shown that this system has a three phase (LLV) coexistence line starting from 215.9 K, and ending at 222.6 K [48].…”

Phase behaviour in the vicinity of the three-phase solid–liquid–vapour line in asymmetric nonpolar systems at high pressures

“…The results obtained make it possible to formulate general rules according to which the basic fluid phase diagrams are modified by the appearance of solid phases. Solid-fluid equilibria have been comprehensively investigated and described by Peters [12], Koningsveld and Diepen [13] and Miller and Luks [14]. In this chapter only types of phase diagrams, which are relevant for the discussion of phase behaviour presented further in this work, are described in more detail.…”

“…(14) means that the enthalpy of condensation of a gaseous mixture with the solute mole fraction x V vanishes. The high temperature branch of the solid-liquid-vapour line emerges at the triple point of the solute and runs to higher pressures and lower temperatures up to the point of temperature minimum.…”

“…In this intermediate state, the low-temperature part of the LLV line is covered by the formation of the solid phase. The reader not familiar with these phenomena is referred to the work of Peters [12], Koningsveld and Diepen [13] and Miller and Luks [14] where the transition phase diagrams have been described in details. Beyond a certain difference in size between the solute and the solvent, the system shows a phase diagram with the formation of solid phase at high temperatures.…”

Determination of Three-Phase Boundaries of Solvent(s)–CO2–Heavy Oil Systems under Reservoir Conditions

“…Figure 3 also includes the measured K points (where the L 2 phase and V phase become critically identical 28 ) for four CO 2 −heavy alkane binaries, i.e., CO 2 −n-C 14 H 30 binary, CO 2 −C 15 H 32 binary, CO 2 −n-C 19 H 40 binary, and CO 2 −n-C 21 H 44 binary. 29 Similar to the CO 2 −heavy alkane binaries, emergence of three-phase coexistence in a CO 2 −heavy oil binary is attributed to the presence of an excessive CO 2 concentration in the binary mixture. The estimated end point of the L 1 L 2 V phase boundary (i.e., the K point) is also shown in Figure 3.…”