Pitzer

Lewis G N and Randaii M 1961 Thermodynamics 2nd edn, ed K S Pitzer and L Brewer (New York McGraw-Hiii)... 

Pitzer K S 1995 Ionic fluids near-critical and related properties J. Phys. Chem. 99 13 070... 

The corresponding states approach suggested by Pitzer et al. requires only the critical temperature and acentric factor of the compound. For a close approximation, an analytical representation of this method proposed by Reid et al. " for 0.6 [Pg.394]

For prediction of vapor density of pm e hydi ocaihon and nonpolar gases, tbe corresponding states method of Pitzer et al. is tbe most accurate method, witb errors of less than 1 percent except in tbe critical region where errors of up to 30 percent can occur. Tbe method correlates tbe compressibibty factor by Eq. (2-75), after which tbe density can be calculated by Eq. (2-75) ... 

FIGt 2-35 Generalized compressibility factors—Pitzer Method, simple fluid term. 

Lee and Kesler fit the entire Pitzer method to equations, rewriting the basic Eq. (2-75) with respect to a heavy reference fluid (n-octane) as shown by Eq. (2-78). 

For hydrocarbon and nonpolar gas mixtures, the Pitzer pure component method can be used to predict vapor density by replacing the true critical properties with pseudocritical properties defined in... 

Pitzer s Corresponding-States Correlation A three-parameter corresponding-states correlation of the type developed by Pitzer, K.S. Thennodynamic.s, 3ded., App. 3, McGraw-HiU, New York, 1995) is described in Sec. 2. It has as its basis an equation for the compressibility factor ... 

Although the Pitzer correlations are based on data for pure materials, they may also be used for the calculation of mixture properties. A set of recipes is required relating the parameters T, Pc, and (0 for a mixture to the pure-species values and to composition. One such set is given by Eqs. (2-80) through (2-82) in Sec. 2, which define pseudopa-rameters, so called because the defined values of T, Pc, and (0 have no physical significance for the mixture. 

Perhaps the most useful of all Pitzer-type correlations is the one for the second virial coefficient. The basic equation (see Eq. [2-68]) is... 

Here 1/ is the effective potential and a>i i is a nodeless pseudo-orbital that can be derived from Xi, in several different ways. For first-row atoms, Christiansen, Lee and Pitzer (1979) suggest... 

---