A Systematic Study of Cubic Equations of State with van der Waals Mixing Rules and Different Combining Rules in Predicting the Densities of LNG and Natural Gas Model Systems

Authors : Monther AL-MANTHARİ, Majid AL-WADHAHİ, Khashayar NASRİFAR, G. Reza VAKİLİ-NEZHAAD

Pages : 107-116

Doi:10.5541/ijot.528164

View : 11 | Download : 2

Publication Date : 2019-05-23

Article Type : Research Paper

Abstract :Cubic equations insert ignore into journalissuearticles values(EoSs); of state are successfully used in petroleum and natural gas industry. In order to extend these equations to mixtures, van der Waals mixing rules with Lorentz-Berthelot insert ignore into journalissuearticles values(LB); combining rules are often employed; however, the accuracies of these EoSs in predicting the densities of hydrocarbon mixtures are not adequate. The main objective of this study was comparing 13 EoSs coupled with 10 combining rules in predicting the densities of hydrocarbon mixtures. Binary and ternary liquid mixtures, LNG mixtures and synthetic natural gas mixtures comprising 752 data points were collected and used in this study. Results revealed that for predicting the liquid densities of binary and ternary mixtures, the Schmidt and Wenzel insert ignore into journalissuearticles values(SW); EoS coupled with Hudson-McCoubrey insert ignore into journalissuearticles values(HMC); or LB combining rules are the best among the others. The SW EoS coupled with the LB combining rules were also the best in predicting the densities of the LNG mixtures. Additionally, the LB combining rules are the best in predicting natural gas mixtures densities using the Patel and Teja insert ignore into journalissuearticles values(PT);, SW and Patel-Teja-Valderrama insert ignore into journalissuearticles values(PTV); EoSs. In general, it was found that the Redlich-Kwong insert ignore into journalissuearticles values(RK); family EoSs, SW and Trebble-Bishnoi-Salim insert ignore into journalissuearticles values(TBS); EoSs are best coupled with the LB combining rules. However, the Peng and Robinson insert ignore into journalissuearticles values(PR); family EoSs with Halgren insert ignore into journalissuearticles values(HHG); combining rules were in better agreement with experimental data. The Waldman-Hagler insert ignore into journalissuearticles values(WH); combining rules lacked predictability when coupled with the most EoSs.
Keywords : Density, Natural Gas, Hydrocarbon, Equation of State