Phase equilibrium diagram boiling

FIGURE 15.4 Phase equilibrium diagram for a binary mixture of components C and D forming a minimum boiling azeotrope (from Hewitt et al. [13], with permission. Copyright CRC Press, Boca Raton, FL). 

Figure 3.1 is a schematic one-component, three-phase equilibrium diagram. The three different phase regions are separated by lines D-TP (solid vapor pressure, or sublimation curve), F-TP (melting point curve), and TP-C (liquid vapor pressure or boiling-point curve). Point C is the critical point where the vapor and liquid phases become indistinguishable and TP is the triple point where solid, liquid, and vapor phases can coexist. There are only two in-... 

The Clapeyron equation, Equation (5.1), yields a quantitative description of a phase boundary on a phase diagram. Equation (5.1) works quite well for the liquid-solid phase boundary, but if the equilibrium is boiling or sublimation - both of which involve a gaseous phase - then the Clapeyron equation is a poor predictor. 

Fig. 2.1. p-T diagram showing phase equilibrium lines, the triple point (tp), boiling point (bp) and critical point for water. 

Figure 5.2-5 shows equilibrium diagrams for bionry systems containing maximum boiling (acetone-chiorofoiro) and minimum boiling (ethanol-water) azeotropes. It also shows an example of an azeotrope which, when condensed, forms two liquid phases (n-bulanoi-water) this is called a heterogeneous azeotrope,... 

Fig. 2.1-21 Top row partial pressure and total pressi e vs. the mole fraction in the hquid phase for different binary mixtures. Center row boiling temperature vs. the mole fraction in the liquid, respectively, in the vaporous phase for different mixtures. Lower row equilibrium diagrams for different mixtures at 1 bar in the center column a mixture is shown that behaves ideal. The mixtures to the left show positive, the mixtures to the right show negative deviations from Raoult s law...

The relationship between boiling lens and h/x diagram are graphically presented in Fig. 5.2-12. In principle, the intensive quantity temperature is replaced by the extensive quantity enthalpy. The isotherms drawn between dew point and boiling point lines represent the phase equilibrium. 

Fig. 1-25. Boiling diagram (a) and equilibrium diagrams (b) for a system showing a limited range of coexistance between the vapor and liquid phases.

The diagram refers to the enthalpy relationships of a completely miscible binary system at a constant pressure of 1 atm. The mole fraction of component B is plotted horizontally from left to right and the enthalpy of the mixture, relative to the pure components in chosen reference states, is plotted vertically. Curve CD represents the enthalpy of the liquid phase, at its boiling-point, as a fimction of composition. Curve EF represents the enthalpy of the vapour above the boiling liquid as a function of its own composition. (Thus CE and DF are the enthalpies of vaporization of A and B respectively.) OH and IJ are typical tie-lines, i.e. a boiling liquid of composition ( is in equilibrium with vapour of composition H,... 

The conditions of temperature and pressure under which a substance exists in different phases, gas, liquid and solid, are summarized in a phase diagram. A simple phase diagram is shown in Fig. 7.1. Under suitable conditions of pressure and temperature, two phases may coexist in thermodynamic equilibrium. Thermodynamic study of phase equilibrium leads to many interesting and useful results. For example, it tells us how the boiling point or freezing point of a liquid changes with the applied pressure. 

Normal phase transition temperatures (i.e., freezing point, boiling point) are those temperatures at which two phases coexist with the pressure at Ibar. A horizontal line drawn on a phase diagram corresponding to a pressure of 1 bar crosses the phase equilibrium curves at the normal phase transition temperatures. 

The phase diagram shown is for mixtures of HCl and H2O at a pressure of 1 atm. The red curve represents the normal boiling points of solutions of HCl(aq) of various mole fractions. The blue curve represents the compositions of the vapors in equilibrium with boiling solutions. 

The shaded region is that part of the phase diagram where liquid and vapor phases coexist in equilibrium, somewhat in analogy to the boiling line for a pure fluid. The ordinary liquid state exists on the high-pressure, low-temperature side of the two-phase region, and the ordinary gas state exists on the other side at low pressure and high temperature. As with our earlier example, we can transform any Type I mixture... 

Fig. 3.2. A stylized phase diagram for a simple pure substance. The dashed line represents 1 atm pressure and the intersection with the solid-liquid equilibrium line represents the normal boiling point and the intersection with the liquid-vapor equilibrium line represents the normal boiling point.

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