Comparing Four Compound-specific Cohesion Factor Relationships for Soave–Redlich–Kwong Equation of State

Abstract

The approach described in one of our previous papers (Jr. Taiwan Inst. Chem. Eng., 41, pp. 570Á578, 2010) was applied to the SoaveÁRedlichÁKwong equation of state to develop compound-specific parameters for four different types of cohesion factor models. Compoundspecific parameters for nearly 300 compounds are listed in the paper and can be utilized for the modelling of phase equilibrium of the mixtures of these compounds. Performance of the models was compared based on the accuracy in predicting various pure compound properties as well as vapour liquid equilibrium of binary systems. The modified Trebble Bishnoi (mGAS) type of cohesion factor model emerged as the best amongst the compared models. Generalization of compound-specific models was also done. These expressions would be useful in the absence of compound-specific parameters.

The Patel–Teja and the Peng–Robinson EoSs performance when Soave alpha function is replaced by an exponential function

“…The Joshipura et al function [38] = exp(J(1 − T r )) (11) The functionality of the Joshipura et al alpha function was proposed by Trebble and Bishnoi [18]. A switching function depending of the acentric factor magnitude can be found in the literature [45].…”

“…(36), A 12 , A 21 and ˛1 2 in Eq. (38). For ˛1 2 a value of 0.47 can be fixed according to the literature taking in account that systems are formed by an alcohol (associative polar) and an alkane or an aromatic (non-polar) [75].…”

“…Vapor pressure, saturated liquid volume, saturated vapor volume and vaporization enthalpy experimental data have been employed to make the evaluation. The chosen alpha functions are: the Soave alpha function [6] and the exponential alpha functions proposed by Haghtalab et al [1], Gasem et al [32], Melhem et al [36], Joshipura et al [38] and Heyen [39]. The last five functions were selected to determine how the EoSs performance changes when the number of the parameters in the exponential alpha function is altered.…”

“…To solve this problem, some exponentials alpha functions has been proposed [9]. In the literature, there are different exponential functions available [1,14,18,32,[35][36][37][38][39].…”