Liquid Viscosities of the Ternary System Benzene + Cyclohexane + n-Tetradecane from (313 to 393) K and Pressures up to 60 MPa Miguel A. Herna ´ndez-Galva ´n, † Fernando Garcı ´a-Sa ´nchez,* ,† and Ricardo Macı ´as-Salinas ‡ Laboratorio de Termodina ´mica, Programa de Investigacio ´n en Ingenierı ´a Molecular, Instituto Mexicano del Petro ´leo. Eje Central La ´zaro Ca ´rdenas 152, 07730 Me ´xico, D.F., Me ´xico, and Departamento de Ingenierı ´a Quı ´mica, SEPI-ESIQIE, Instituto Polite ´cnico Nacional, Unidad Profesional Adolfo Lo ´pez Mateos, Zacatenco, 07738 Me ´xico, D.F., Me ´xico Liquid viscosities of eight mixtures for the ternary system benzene + cyclohexane + n-tetradecane were experimentally measured using a rolling-ball viscometer from (313.2 to 393.2) K and at pressures up to 60 MPa. We performed the modeling of the measured mixture viscosity data (256 points) by applying the Grunberg-Nissan (GN) and Katti-Chaudhri (KC) correlations and a liquid viscosity model based on Eyring’s theory coupled to a cubic equation of state (ET-EoS) by using a single temperature-independent binary interaction parameter for the benzene + n-tetradecane, benzene + cyclohexane, and cyclohexane + n-tetradecane systems. Results of the modeling process yielded an average absolute deviation of (4.9, 5.3, and 6.7) % for the GN, KC, and ET-EoS viscosity models, respectively, which show that the GN model is superior to the KC and ET-EoS models in predicting the whole viscosity-temperature-pressure-composition surface of the ternary system studied. Introduction Knowledge of the dynamic viscosity of petroleum fluids under reservoir conditions is important for simulating reservoir production systems and designing transport equipments. In this context, a significant number of systematic studies have appeared in the literature that deal with the liquid viscosity of binary mixtures mostly at atmospheric pressure. In an effort to characterize the viscosity behavior of a petroleum fluid or a petroleum cut more realistically, only a few systematic studies have been reported so far for ternary mixtures over wide temperature and pressure ranges. Among these, for example, Iglesias-Silva et al. 1 measured the liquid viscosity of the system pentane + octane + decane using a rolling-ball viscometer at temperatures from (298.15 to 373.15) K and at pressures up to 25 MPa over the entire composition range. The authors compared their experimental results (540 points) to the correla- tion proposed by Assael et al. 2 and obtained an agreement within ( 6 %. In another related work, Zeberg-Mikkelsen et al. 3 reported comprehensive viscosity and density measurements for the ternary system 1-methylnaphtalene + n-tridecane + 2,2,4,4,6,8,8- heptamethylnonane at high pressures (up to 100 MPa) and within the temperature range of (293.15 to 353.15) K. They used a falling-body viscometer to measure the dynamic viscosity above 0.1 MPa. At atmospheric pressure (0.101 MPa), however, a Ubbelohde viscosimeter was used by the authors. Their viscosity results comprised a total of 882 experimental points and were interpreted in terms of various mixing laws and the Eyring theory as well. Similarly, Zeberg-Mikkelsen et al. 4 measured the dynamic viscosity and density of 13 ternary mixtures containing methylcyclohexane + cis-decalin + 2,2,4,4,6,8,8- heptamethylnonane over the temperature range of (293.15 to 353.15) K and up to 100 MPa. Their viscosity measurements yielded a total of 546 experimental points. Two simple mixing laws (Grunberg-Nissan (GN) and Katti-Chaudrhi (KC)) were considered by the authors for correlating purposes. More recently, Zeberg-Mikkelsen et al. 5 revisited their previous viscosity work for the ternary mixture methylcyclo- hexane + cis-decalin + 2,2,4,4,6,8,8-heptamethylnonane (Ze- berg-Mikkelsen et al. 4 ) to perform a comparative study of various viscosity models. In doing so, they considered two mixing laws (GN 6 and KC 7 ), a self-referencing model, 8 the Lohrenz-Bray-Clark (LBC) correlation, 9 a hard-sphere scheme, 10,11 a free-volume viscosity model, 12,13 and the friction theory. 14,15 As demonstrated by the authors, the performance of all of the models in predicting the viscosity of the afore- mentioned ternary mixture was quite similar, with the GN and the friction theory approach giving the smallest deviations between calculated and experimental viscosity values. In an attempt to expand the availability of viscosity measure- ments for pure hydrocarbon and their mixtures over a wide range of temperature and pressure, we previously initiated a systematic study of liquid viscosities of mixtures containing paraffin, aromatic, and naphthenic compounds. Accordingly, we first presented experimental liquid viscosities for n-tetradecane, benzene, and cyclohexane, and its corresponding binary systems at the temperature range of (313.2 to 393.2) K and at pressures up to 60 MPa (Herna ´ndez-Galva ´n et al. 16,17 ). As a continuation of previous work, we report here liquid viscosity measurements for the ternary system benzene + cyclohexane + n-tetradecane from (313.2 to 393.2) K and at pressures up to 60 MPa over the entire composition range. Dynamic viscosity data for this system were determined in a high-pressure rolling-ball viscom- eter using a density Tait-type correlation reported by Assael et al. 18 for n-tetradecane and by Cibulka and Takagi 19,20 for benzene and cyclohexane. * To whom correspondence should be addressed. Tel: +52 55 9175 6574. E-mail: fgarcias@imp.mx. † Instituto Mexicano del Petro ´leo. ‡ Instituto Polite ´cnico Nacional. J. Chem. Eng. Data 2009, 54, 1329–1333 1329 10.1021/je8009122 CCC: $40.75  2009 American Chemical Society Published on Web 03/10/2009