A cubic equation of state with a new alpha function and a new mixing rule

Improvements of the Patel-Teja equation of state

“…Many of these forms have been shown to give the correct asymptotic behavior for the vs temperature curve to overcome the deficiency present in the original form used by the S-R-K, P-R, P-T, and other popular equations of state. As mentioned elsewhere [1][2][3]15 ], the original functional form containing .only one adjustable parameter is good for the reduced temperature range of 0.7 and higher but gives large errors at lower reduced temperatures. To improve the accuracy of the vapor pressure representation, two or more adjustable parameters are required to describe the a vs temperature relationship.…”

“…It is also possible to extend the use of the equation of state to calculate vapor pressure in the temperature range where experimental measurement of vapor pressure is difficult but the heat capacity data can be easily measured, e.g., high-boiling compounds at or near room temperature. The use of liquid heat capacity data is not new; Ambrose and Davies [ 13] and King and A1-Najjar [ 14] have used low-temperature heat capacity data to extend vapor pressure equations, and recently Twu et al [2] recommended the use of heat capacity data to improve the temperature dependence of the S-R-K equation of state.…”

“…First, the improvement in the temperature dependent term, often called the "alpha (oc)" term, has led to better .matching of the pure component vapor pressure curve along the saturation line and, second, the improvement in the representation of mixtures through better and more versatile mixing rules has led to correlation of vapor-liquid equilibrium data with the same quality usually found with the activity coefficient approach. Both of these topics have received significant attention in the last few years [1][2][3].…”

Thermodynamic Models for the Prediction of Petroleum-Fluid Phase Behaviour

“…Compared to the original PR EoS, this alpha function uses a higher order polynomial function in the acentric factor for the m parameter that allows a better modelling of heavy-hydrocarbon phase behaviour. Twu et al, 1991Twu et al, , 1995aTwu et al, , 1995b proposed two different alpha functions. The first one requires -for each pure component -to fit the model parameters (N, M and L) on experimental pure-component VLE data:…”

An extended corresponding states equation of state (EoS) for CCS industry

“…The SRK-HV implementation used in this work has parameters regressed over a wide range of CO 2 -water data, and the regression work is described in detail by Austegard et al (2006). The SRK-HV evaluated in this work uses the Twu-Bluck-Cunningham (TBC) (Twu et al, 1991) formulation for computing the alpha parameter.…”