The second common procedure for VLE calculations is the equation-of-state approach. Here, fugacity coefficients replace the fugacities for both Hquid and vapor phases, and equation 220 becomes equation 226 [Pg.499]

The general low-pressure VLE calculation procedure for mixtures with more than two species is the same as for two species we attempt to find equations for the fugacities in gas and liquid phases that present/] as a function of T, P, and the mol fractions in that phase. As the number of species goes up, the mathematical complexity increases and the intuitive [Pg.153]

This chapter discussed VLE and the calculation procedures for binary and multiconponent flash distillation. At this point you should be able to satisfy the following objectives [Pg.100]

MODIFICATION OF PROGRAM TO CaLCJLATE PHASE EQUILIBRIA BY PROCEDURES AND COEFFICIENTS USED IN VLE PROGRAM, USES MODIFIED VAN L A COEFFICIENTS AT 3 TEMPS. CALCULATES ThETAS. GAMMAS AND COMPLETE PHASE EQUILIBRIA AT EACH STAGE. [Pg.84]

Because of the complex concentration functionality of the m-values, VLE calculations in general require iterative procedures suited only to computer solutions. However, in the case of mixtures of light hydrocarbons, we may assume as a reasonable approximation that both the liquid and the vapor phases are ideal. This allows m-values for light hydrocarbons to be calculated and correlated as functions of T and P. Approximate values can be determined from the monographs prepared by DePriester (1953). The DePriester charts have been fit to the following equation (McWilliams, 1973) [Pg.408]

Current process design computer programs mostly calculate high-pressure VLE using cubic EOSs, of which the SRK is one of the most popular. The procedure is as illustrated in Example F.5/10.3. [Pg.178]

Once procedures for calculating pure-component parameters and mixing rules are established, the calculation of component fugacity coefficients 4>i for both vapor and liquid phases follows standard procedures (see e.g. (4)). For VLE calculations, the distribution of components between phases is expressed generally as the K-value—the vapor mole fraction divided by the liquid mole fraction—related to fugacity coefficients for each component by [Pg.258]

In VLE correlation (data reduction), one again requires values for the By, and t, but here the goal is to determine from VLE data bret values for the parameters in an assum expression for g in effect, to find liquid-phase activity coefficients from VLE data. Data reduction procedures combine VLE calculations with nonlinear regression techniques and again require use of a computer this topic is discussed by Van Ness and Abbott and by Prausnitz et al. [Pg.37]

F. Generalize. If K values depend on conposition, then an extra loop in the trial-and-error procedure will be required. When K values are in equation form such as Eq. (2=30), bubble-point calculations are easy to solve with a spreadsheet. With a process simulator, one of the vapor-liquid equilibrium (VLE) correlations (see Table 2-41 will be used to find the bubble-point tenperature and they,- [Pg.235]

With the help of the binary parameters kn or g -model parameters now the phase equilibrium behavior, densities, enthalpies, Joule-Thomson coefficients, and so on, for binary, ternary and multicomponent systems can be calculated. For the calculation of the VLE behavior the procedure is demonstrated in the following example for the binary system nitrogen-methane using classical mixing rules. The same procedure can be applied to calculate the VLE behavior of multicomponent systems and with g -mixing rules as well. [Pg.243]

Both mass transfer resistances are interconnected in a rather complex manner. The structure of these interconnections was made visible by the presentation of analytical solutions which could be easily handled on a spreadsheet calculation tool, even for much more complicated VLE equations with variable relative volatilities and chemical equilibrium equations of any complexity because no integration procedure is necessary, but just finding roots. [Pg.126]

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