Liquid phases computer program

The calculation of vapor and liquid fugacities in multi-component systems has been implemented by a set of computer programs in the form of FORTRAN IV subroutines. These are applicable to systems of up to twenty components, and operate on a thermodynamic data base including parameters for 92 compounds. The set includes subroutines for evaluation of vapor-phase fugacity... 

VPLQFT is a computer program for correlating binary vapor-liquid equilibrium (VLE) data at low to moderate pressures. For such binary mixtures, the truncated virial equation of state is used to correct for vapor-phase nonidealities, except for mixtures containing organic acids where the "chemical" theory is used. The Hayden-0 Connell (1975) correlation gives either the second virial coefficients or the dimerization equilibrium constants, as required. 

A computer program (TWOPHASE) was developed that uses the Lockliart-Matinelli correlation and determines the total pressure drop based on the vapor phase pressure drop. The total length of the unit depends on the nature of the Reynolds numher. The program also calculates the gas-liquid phase regime employing a modified Baker s map [33]. Table 7-13 gives the results of the two-phase pressure drop. 

In a reversed-phase liquid chromatography system, if the hydrogen-bonding and Coulombic forces are negligible, the retention of molecules depends upon their size, and the presence of n electrons enhances the selectivity. The molecular size, i.e. the van der Waals volume, can be calculated by hand, by Bondi s method,29 or by certain computer programs. 

The most reliable methods for fully developed gas/liquid flows use mechanistic models to predict flow pattern, and use different pressure drop and void fraction estimation procedures for each flow pattern. Such methods are too lengthy to include here, and are well suited to incorporation into computer programs commercial codes for gas/liquid pipeline flows are available. Some key references for mechanistic methods for flow pattern transitions and flow regime-specific pressure drop and void fraction methods include Taitel and Dukler (AIChEJ., 22,47-55 [1976]), Barnea, et al. (Int. J. Multiphase Flow, 6, 217-225 [1980]), Barnea (Int. J. Multiphase Flow, 12, 733-744 [1986]), Taitel, Barnea, and Dukler (AIChE J., 26, 345-354 [1980]), Wallis (One-dimensional Two-phase Flow, McGraw-Hill, New York, 1969), and Dukler and Hubbard (Ind. Eng. Chem. Fun-dam., 14, 337-347 [1975]). For preliminary or approximate calculations, flow pattern maps and flow regime-independent empirical correlations, are simpler and faster to use. Such methods for horizontal and vertical flows are provided in the following. 

This factor should be inputted if you have chosen the two-film method. Enter the value of the chosen light key component liquid phase mole fraction. This value should be obtained from an equilibrium curve, a two-component binary system, or a tray-to-tray computer program printout. The program uses this factor to calculate the slope of the equilibrium curve. Be sure to select the liquid light key mole fraction at the proper curve point or tray condition that corresponds to the K value used. 

Computer simulation programs are useful engineering tools for design, optimization, and control of production and manufacturing processes. A simulator for equilibrium processing of hydrocarbons, petroleum, and associated gases in co-existing vapor and liquid phases will be described in this paper. 

From Equations 1 and 2, the phase equilibria depend upon knowing the pure component vapor pressures P 0, liquid phase activity coefficients ji and imperfection-pressure coefficients ft. The computer program which has been developed uses any of four different vapor pressure equations for providing Pi°. It uses the modified van Laar Equations (5) to give liquid phase activity coefficients and a Modified van der Waals Equation of State (4,6) to give imperfection-pressure coefficients ft. 

Correlation of Liquid Phase Activity Coefficients. For activity coefficients to be used in distillation calculations, they are normally represented as a function of composition. Here a multiple regression computer program was used to determine the coefficients for an equation of the form... 

Thus for bubblepoint calculations, where die liquid-phase composition is known, the problem is to find die set of K-values diat satisfies Eq. (14.53). A block diagram of a computer program forBUBL P calculations is shown by Fig. 14.8. 

In our case a new column was manufactured (J W Scientific, Inc., DB-1301) using a suitable mixture of the 2 stationary phases determined hy a computer program. This liquid phase has been shown to have the same or similar characteristics as the coupled columns [15 ]. This line of investigation shows promise in solving many environmentally related analytical separations. 

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