APOR-LIQUID EQUILIBRIUM

Figure 14.9 V apor-liquid equilibrium data and calcidated values for the diethyl-amine-water system. Calculations were done using parameters from simplified CLS estimation [reprinted from Computers Chemical Engineering with permission from Elsevier Science].

Calculate the volume of packing required for the desorption column. V apor-liquid equilibrium data from Example 16.4 can be used and KaO = 4 Ibmole/hr ft atm (partial pressure). 

Alternatively, after selecting flie set of correlated data, choose the menu entry Ffle/XML FfteA apor-liquid equilibrium or File/XML Ffle /Excess Gibbs energies command (Fig. 3.21). 

V apor pressure is an important property of liquids, and to a much lesser extent, of solids. If a liquid is allowed to evaporate in a confined space, tlie pressure of tlie vapor phase increases as tlie amount of vapor increases. If tliere is sufficient liquid present, tlie pressure in tlie vapor space eventually comes to equal exactly tlie pressure exerted by the liquid at its own surface. At tliis point, a dynamic equilibrium exists in wliich vaporization and condensation take place at equal rates and tlie pressure in tlie vapor space remains constant. The pressure exerted at equilibrium is called tlie vapor pressure of the liquid. Solids, like liquids, also exert a vapor pressure. Evaporation of solids (sublimation) is noticeable only for tlie few solids characterized by appreciable vapor pressures. 

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