Fugacity correction parameters

The ideal gas model cannot be used at high pressures. Under these conditions, as pointed out in section 2.9, we have to deal with fugacities. Neglecting this and other correction parameters may lead to large errors. The point can be illustrated with results obtained by Oldani and Bor, who studied equilibrium 14.21 in hexane over the temperature range of -21.5 to 19.6°C and under a CO pressure of 198 bar [317],... 

The Lee-Erbar-Edmister method is of the same type, but uses different expressions for the fugacity and activity coefficients. The vapor phase equation of state is a three-parameter expression, and binary interaction corrections are included. The liquid phase activity and fugacity coefficient expressions were derived to extend the method to lower temperatures and to improve accuracy. Binary interaction terms were included in the liquid activity coefficient equation. 

In a significant departure from conventional practice, Chueh and Prausnitz (11,12) proposed that the critical constraints on the RK equation be relaxed, and that parameters b and c be treated as empirical constants, determined separately for the liquid phase and for the vapor phase of a given substance. The conventional RK expression for (T) was retained the application was to vapor-liquid equilibrium calculations, in which the vapor-phase version of the equation was used for computation of vapor-phase fugacity coefficients, but in which the liquid-phase version was used only for Poynting corrections. Thus, they proposed that... 

Coefficient in Wohl Eq.(13) y = Constant used in BWR-11 Eq. (Table II) y = Activity coefficient of a component in liquid 6 = Solubility parameter v(0) = Simple fluid liquid fugaclty coefficient v(l) = Liquid fugacity coefficient correction term TT = System pressure... 

Add a species to the mixture by using the Add button. Choose the desired fugacity and activity coefficient corrections at the bottom of the window. If the multicomponent Wilson model is used, the model parameters should entered by choosing Edit in the Wilson Model Parameters frame. Once everything is set, choose Solve Unknowns to perform the bubble-point or dew-point calculation. Choose More Information to see the values of the correction factors at equilibrium. 

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