Within the two-phase envelope, the R-K equation has continuity, but it fails badly to predict an isobaric condition. This has no serious practical implications. If the molal volume for a two-phase mixture is required, it can be computed directly from individual phase volumes. [Pg.469]

Figure 5. The two phase envelopes of the binary DiPA-H20 and DMiPA-H20 systems and of the ternary DiPA-H20-NaClsat and DMiPA-H20-NaClsat systems. Below the phase lines there is one single liquid phase and above there are two liquid phases present. |

In the P,7-section the two-phase envelope is tangent to the binary critical curve in the critical point. [Pg.29]

Figure 5.23 shows the phase envelopes for the different types of hydrocarbons discussed, using the same scale on the axes. The higher the fraction of the heavy components in the mixture, the further to the right the two-phase envelope. Typical separator conditions would be around 50 bara and 15°C. [Pg.104]

Methane, a common impurity in acid gas, tends to broaden the phase envelope because it is lighter than the acid gas components. Figure 3.6 shows two phase envelopes. The first is the phase envelope for an equimolar mixture of hydrogen sulfide and carbon dioxide. This is the same phase envelope shown in figure 3.2. The other phase envelope is for a mixture with 2 mol% methane. [Pg.78]

An equation of state is an algebraic expression that can represent the phase behavior of the fluid, both in the two-phase envelope (i.e., inside the binodal curve), as was demanded above, on the two-phase envelope, and outside the binodal curve. The equations of state are divided into two main groups cubic and noncubic. Cubic equations have three roots when T and only one root when T > T. At T = T, there are three equal roots. Figure. 3.4 portrays the deficiency with most of the cubic equations of state. In this plot, the solid circles show measured data and the solid line represents the predictions from an EOS. The flatness around the critical point can not be adequately described by most cubic equations. The liquid phase description is also not so good as the description of the gas phase. Later, we will discuss how the volume- [Pg.133]

In addition, the separator temperature and pressure of the surface facilities are typically outside the two-phase envelope, so that no liquids form during separation. This makes the prediction of the produced fluids during development very simple, and gas sales contracts can be agreed with the confidence that the fluid composition will remain constant during field life in the case of a dry gas. [Pg.102]

When the two components are mixed together (say in a mixture of 10% ethane, 90% n-heptane) the bubble point curve and the dew point curve no longer coincide, and a two-phase envelope appears. Within this two-phase region, a mixture of liquid and gas exist, with both components being present in each phase in proportions dictated by the exact temperature and pressure, i.e. the composition of the liquid and gas phases within the two-phase envelope are not constant. The mixture has its own critical point C g. [Pg.100]

The experiment could be repeated at a number of different temperatures and initial pressures to determine the shape of the two-phase envelope defined by the bubble point line and the dew point line. These two lines meet at the critical point, where it is no longer possible to distinguish between a compressed gas and a liquid. [Pg.99]

No, a straight line from the point 35 mole percent methane, 65 mole percent ethane plus to the apex at pure carbon dioxide passes through the two-phase envelope. [Pg.80]

The density effect can also be examined in terms of liquid-liquid phase equilibria thermodynamics Increasing the continuous phase density Increases the entropy of mixing by lowering the free volume difference between the constituents. Thus the various two-phase envelopes (water-oil, oil-surfactant, and water-surfactant) that combine to affect the emulsion stability will shrink upon increasing density (2H) [Pg.190]

The four vertical lines on the diagram show the isothermal depletion loci for the main types of hydrocarbon gas (incorporating dry gas and wet gas), gas condensate, volatile oil and black oil. The starting point, or initial conditions of temperature and pressure, relative to the two-phase envelope are different for each fluid type. [Pg.102]

Using the Peng-Robinson equation-of-state programs or MATHCAD worksheets described in Appendix B, we obtain the results in Table 7.5-1. The vapor pressure as a function of temperature is plotted in Fig. 7.5-3. The specific volumes and molar enthalpies and entropies of the coexisting phases have been added as the two-phase envelopes in Figs. 6.4-3, 6.4-4, and 6.4-5.B [Pg.308]

Example 4.1. Thermodynamic properties of isobutane were measured at subcritical temperatures from 70°F (294.29°K) to 250°F (394.26°K) over a pressure range of 10 psia (68.95 kPa) to 3000 psia (20.68 MPa) by Sage and Lacey. Figure 4.1 is a log-log graph of pressure (psia) versus molal volume (fP/lbmole) of the experimental two-phase envelope (saturated liquid and saturated vapor) using the tabulated critical conditions from Appendix I to close the curve. Shown also is an experimental isotherm for 190°F (360.93°K). Calculate and plot 190°F isotherms for the R-K equation of state and for the ideal gas law and compare them to the experimental data. [Pg.468]

In Fig. 3.3a, we present the Txy diagram for binary mixtures of cyclohexane and toluene at a pressure of 1 atm, which is below the critical pressure of both pure species. Point A denotes the boiling temperature of pure toluene, and point C is the boiling temperature of pure cyclohexane. Connecting these two points are two curves that form the two-phase envelope. The upper curve (with the open symbols) is the dew point curve, and the lower curve (with the filled symbols) is the bubble point line. [Pg.27]

For both volatile oil and blaok oil the initial reservoir temperature is below the critical point, and the fluid is therefore a liquid in the reservoir. As the pressure drops the bubble point is eventually reached, and the first bubble of gas is released from the liquid. The composition of this gas will be made up of the more volatile components of the mixture. Both volatile oils and black oils will liberate gas in the separators, whose conditions of pressure and temperature are well inside the two-phase envelope. [Pg.104]

See also in sourсe #XX -- [ Pg.800 , Pg.806 , Pg.818 ]

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