Phase diagrams pressure-temperature

So far we have considered only a single component. However, reservoir fluids contain a mixture of hundreds of components, which adds to the complexity of the phase behaviour. Now consider the impact of adding one component to the ethane, say n-heptane (C7H.,g). We are now discussing a binary (two component) mixture, and will concentrate on the pressure-temperature phase diagram. 

Figure 5.20 Pressure-temperature phase diagram mixture of ethane and n-heptane...

Figure A2.5.11. Typical pressure-temperature phase diagrams for a two-component fluid system. The fiill curves are vapour pressure lines for the pure fluids, ending at critical points. The dotted curves are critical lines, while the dashed curves are tliree-phase lines. The dashed horizontal lines are not part of the phase diagram, but indicate constant-pressure paths for the T, x) diagrams in figure A2.5.12. All but the type VI diagrams are predicted by the van der Waals equation for binary mixtures. Adapted from figures in [3].

Figure 9.1. Carbon dioxide pressure-temperature phase diagram adapted from McHugh and Krukonis (1994).

Brady et al. [52] have discussed pressure-temperature phase diagrams for carbon dioxide polychlorobiphenyls and examined the rate process of desorption from soils. Supercritical carbon dioxide was used to extract polychlorobiphenyls and DDT and Toxaphene from contaminated soils. 

Figure 5.37. Pressure/temperature phase diagram of carbon.

Schirber JE, Overmyer DL, Carlson KD, Williams JM, Kini AM, Wang HH, Charlier FIA, Love BJ, Watkins DM, Yaconi GA (1991) Pressure-temperature phase diagram, inverse isotope effect, and superconductivity in excess of 13 K in /c-(BEDT-TTF)2Cu[N(CN)2]Cl, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene. Phys Rev B44 4666-4669... 

Only for U, Np and Pu sufficient experimental work was carried out so that a pressure-temperature phase diagram can be constructed. 

In fact, iron exhibits all three common metallic crystal structures bcc, fee, and hep within its pressure-temperature phase diagram, as is shown by the inset of Fig. 8.14. The transition from the bcc a phase to the hep e phase... 

Figure 2.14 Pressure-temperature phase diagram for cyclopropane. (Reproduced from Majid, Y.A., Garg, S.K., Davidson, D.W., Can. J. Chem., 47,4697 (1969). With permission from the National Research Council of Canada.)...

What is a typical pressure-temperature phase diagram for sH hydrates ... 

In Figure 4.2c for natural gases without a liquid hydrocarbon (or when liquid hydrocarbons exist below 273 K), the lower portion of the pressure-temperature phase diagram is very similar to that shown in Figure 4.2a. Two changes are (1) the Lw-H-V line would be for a fixed composition mixture of hydrocarbons rather than for pure methane (predictions methods for mixtures are given in Section 4.2 and in Chapter 5) and (2) quadruple point Qi would be at the intersection of the Lw-H-V line and 273 K, at a pressure lower than that for methane. The other three-phase lines of Figure 4.2a (for I-Lw-H and I-H-V) have almost the same slope at Qj. Otherwise, the same points in Section 4.1.1 apply. 

Figure 15.5. Pressure-temperature phase diagram of pure C02 with a superimposed flow diagram for a closed-loop supercritical fluid treatment process.

Fig. 45. (b) Pressure-temperature phase diagram below room temperature for Lao 86 r0.l4MnO3, after Zhou and Goodenough (2000). 

Fig. 2 Approximate pressure-temperature phase diagram showing the boundaries between the three phases of molecular C60. Dashed lines in the simple cubic field show coordinates corresponding to 30,50,65,80, and 92% H-oriented molecules...

Fullerenes with more than 70 atoms have been very little studied under pressure. The pressure-temperature phase diagram of molecular C76 was investigated up to 5 GPa near room temperature by Nakao et al. [166] but polymerization was... 

Mn3+, estimated to be about 198 kJ/g.ion in the andalusite Ml site, is that it increases the stability field of viridines in the pressure-temperature phase diagram for the system Al2Si05-(Al1 Mnx)2Si05 where x < 0.2 (Abs-Wurmbach et al., 1981 Langer, 1988). The influence of CFSE on the stability field of Mn3+ andalusite is discussed in chapter 7 ( 7.7.4.1). 

Fig. 11. A typical pressure-temperature phase diagram for a single-component system, e.g., xenon, showing the supercritical region, which can he accessed from either the liquid or gas phase without crossing a phase boundary.

Figure 14 Structure of the monoclinic phase of cristobalite viewed down [010] revealing the puckered six-member rings of Si04 tetrahedra. On the right, a schematic pressure-temperature phase diagram...

Bundy E. P. (1965) Pressure—temperature phase diagram of iron to 200kbar, 900 °C. J. Appl. Phys. 36, 616-620. 

Fig. 1 Pressure-temperature phase diagram of a pure component indicating the supercritical region. (From...

Sketch the pressure-temperature phase diagram for a typical substance and identify the lines, areas, and singular points (Section 10.6, Problems 43-52). 

Bundy, F.P. Bassett, W.A. Weathers, M.S. Hemley, R.J. Mao, H.K. Goncharov, A.F. The pressure-temperature phase diagram and transfonna-tion diagram for carbon Updated through 1994. Carbon 1996, 34, 141-153. 

Figure 1 Pressure-temperature phase diagram for a single component.

The pressure-temperature phase diagrams also serve to highlight the fact that the polymorphic transition temperature varies with pressure, which is an important consideration in the supercritical fluid processing of materials in which crystallization occurs invariably at elevated pressures. Qualitative prediction of various phase changes (liquid/vapor, solid/vapor, solid/liquid, solid/liquid/vapor) at equilibrium under supercritical fluid conditions can be made by reference to the well-known Le Chatelier s principle. Accordingly, an increase in pressure will result in a decrease in the volume of the system. For most materials (with water being the most notable exception), the specific volume of the liquid and gas phase is less than that of the solid phase, so that... 

Typical changes in a pressure/temperature phase diagram after adding a nonvolatile solute are found here ... 

Fig. 6.2. Pressure-temperature phase diagrams of a few representative elements (adapted from Young (1991)).

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