Tao-Mason Equation Of State Research Articles

PVT Properties of Pure Lubricants Using Equations of State and Artificial Intelligence

Statistical mechanical and artificial intelligence models are developed to predict the volumetric properties of lubricants under different conditions. It is shown that the knowledge of just liquid density at room temperature is satisfactory to approximate the PVT properties of pure lubricants in various conditions. As well, the performance of an artificial neural network (ANN) based on back propagation training with 7 neurons in a hidden layer for forecasting of behavior of lubricants was investigated. The average absolute deviations from literature for 1269 data points of pure lubricants using the improved Ihm-Song-Mason equation of state, Tao-Mason equation of state and ANN at different conditions are calculated to be 0.75%, 0.25% and 0.17%, respectively.

Application of modified Tao-Mason equation of state to refrigerant mixtures

In our previous work, we modified the Tao-Mason EOS [1] to predict the volumetric properties of pure refrigerants [2]. In the present study, we have successfully extended the modified Tao-Mason EOS to refrigerant mixtures. The second virial coefficient, B2(T), and the temperature-dependent correction factor α(T) and van der Waals co-volume b(T) were calculated from a two-parameter corresponding-states correlation along with the enthalpy of vaporization and the molar density, both at the normal boiling point. Then the cross parameters B12(T), α 12(T), and b12(T), were determined with the help of simple combining rules. The constructed Tao-Mason EOS was employed to predict the densities and vapor pressures of several HFC, hydrocarbons and HFO mixtures. The calculated results were compared with literature data. The overall agreement between our results and literature values is remarkable.

Volumetric properties of ionic liquids and their binary mixtures from improved Tao–Mason equation of state

In this work, the Tao–Mason (TM) equation of state (EOS) has been employed to model the pressure–volume–temperature (PVT) properties of ionic liquids (ILs) by the help of an alternative corresponding state correlation based on the measurable scaling constants, i.e., surface tension and liquid density both at room temperature. Performance of model has been assessed against 2207 experimental data points over a wide temperature range within 293–472K and pressure range from ambient up to 200MPa for 17 imidazolium-based ILs. The average absolute deviation (AAD in %) of the calculated densities from literature values was found to be 0.79%. Generally, this work shows that TM EOS based on the surface tension property of ILs outperforms the previous version of TM EOS which uses normal boiling point properties, i.e. the heat of vaporization and liquid density. Improved TM EOS has also been extended to binary systems formed by ionic liquids to predict their volumetric properties. The performance of the mixture version of improved TM EOS has been assessed against 385 experimental data points, and AAD was found to be 0.78%.

Modification of Tao-Mason equation of state: application to polymer melts

The present work addresses a simplified procedure for the calculation of certain parameters in the Tao-Mason (TM) equation of state (EOS) needed to calculate the volumetric properties of polymer melts using surface tension γf and liquid density at freezing temperature ρf, with scaling parameters at compressed state and in the temperature range of 298.15 to 423.15 K and pressures up to 200 MPa. The polymers in question are polyethylene glycol (PEG), polypropylene glycol (PPG), polypropylene (PP) and polyvinyl choloride (PVC). The calculated densities were in good agreement with the ones obtained from the experimental specific volumes as well as polymer chain-of-rotator (PCOR) EOS. The accuracies were found to be of the order of 1.5%. Finally, the modified TM EOS was further assessed through comparing with the Ihm-Song-Mason (ISM) EOS.

Modification of a statistical mechanically-based equation of state: Application to ionic liquids

It is the purpose of this paper to determine the volumetric properties of some ionic liquids (ILs) using the modified version of Tao–Mason (TM) equation of state (EOS). The studied ILs include the cations: imidazolium, phosphonium, pyridinium, pyrrolidium and anions: tetrafluoroborate, bis(trifluoromethylsulfonyl) imide, and hexafluorophosphate. The densities of these compounds were calculated by the usage of the modified TM EOS at several temperatures and pressures. The most important parameter in this EOS is the second virial coefficient which is calculated from a two-parameter corresponding states correlation along with two constants enthalpy of vaporization and molar density both at 298K. The other remaining parameters (i.e., α(T) and b(T)) that appeared in the EOS were calculated from simple equations. Novelty of this work is the modification of the original TM EOS and usage of enthalpy of vaporization and molar density instead of critical and Boyle parameters in the original TM EOS. The good harmony between the calculated and literature density values of ILs confirms the ability of the modified TM EOS in predicting volumetric properties of this class of fluids. Overall average absolute deviation (AAD) of the calculated densities from 3394 experimental data points is 1.48%.

Tao-Mason equation of state for refractory metals

Tao-Mason equation of state for refractory metals

Modeling vapor–liquid equilibrium of various binary mixtures with a statistically based equation of state

The present study is a continuation of previous work (F. Yousefi, J. Moghadasi, M. M. Papari, A. Campo, Ind. Eng. Chem. Res. 48 (2009) 5079–5084) related to the assessment of the ability of the Tao-Mason (TM) equation of state (EOS) in predicting thermodynamic properties of fluid mixtures. In our previous study, we extended the TM EOS to predict pressure–volume–temperature–composition of fluid mixtures. The present paper aims to model vapor–liquid equilibria of some binary mixtures of ionic liquids, refrigerants, hydrocarbons, and monatomic fluids. In this study, the Sheikh-Papari-Boushehri (SPB) correlations have been employed to predict temperature-dependent parameters appeared in the EOS. The novelty of the present work is the application of Tao-Mason (TM) EOS to fluid phase equilibria of mixtures. The outcomes of the computations are compared with the experimental data. Our results demonstrate that the TM EOS can properly model phase equilibria of fluid mixtures with acceptable accuracies.

Performance assessment of Tao–Mason equation of state: Results for vapor–liquid equilibrium properties

The present work evaluates the performance of a molecular-based equation of state in predicting thermodynamic properties of several fluids in a very wide range of temperatures encompassing 100 K < T < 1100 K and pressures ranging from zero to 3200 bar. The theoretical equation of state (EOS) is that of Tao–Mason (TM) which is based on statistical mechanical perturbation theory. The 21 fluids including: argon (Ar), krypton (Kr), xenon (Xe), nitrogen (N 2), oxygen (O 2), carbon dioxide (CO 2), methane (CH 4), ethane (C 2H 6), propane (C 3H 8), normal butane (n-C 4H 10), isobutene (i-C 4H 10), ethene (C 2H 4), benzene (C 6H 6), toluene (C 7H 8) as well as refrigerants consisting of 1,1,1,2 tetra fluoroethane (R134a), tetrafluoromethane (R14), chlorodifluromethane (R22), 1,1,1-trifluoroethane (R143a), 1,1,1-trifluoro,2,2-dichloroethane (R123), octafluoropropane (R218), and 1,1-difluoroethane (R152a) are selected and compared with literature data. The calculations cover the ranges from the dilute vapor or gas to the highly compressed liquid and supercritical regions. The thermodynamic properties are the vapor and liquid densities, the vapor pressure, the internal energy, the enthalpy, the entropy, the heat capacity at constant pressure and constant volume, and the speed of sound. It was found that the overall agreement with literature in all phases especially the vapor/gas phase is remarkable. Furthermore, the Zeno line regularity can be well represented by the TM EOS. Finally, the TM EOS is further assessed through comparing with the Ihm–Song–Mason (ISM) equation of state. In general, the TM EOS outperforms the ISM equation of state.

Modification of Tao-Mason equation of state: Application to refrigerant fluids

The present work addresses a simplified procedure for the calculation of certain parameters in the Tao-Mason (TM) equation of state needed to estimate thermodynamic properties of 12 ozone–friendly refrigerants fluids. The calculations cover wide ranges extending from the dilute vapor or gas to highly compressed liquid and supercritical region. The theoretical equation of state (EOS) is that of Tao and Mason which is based on statistical mechanical perturbation theory. The novelty of the present work is that we use two scaling constants, the enthalpy of vaporization and the molar density, both evaluated at the normal boiling temperature. This approach contrasts with the original procedure that employs five scaling constants including the critical temperature, the critical pressure, the Boyle temperature, the Boyle pressure and the acentric factor for calculating three parameters second virial coefficient and temperature-dependent parameters. The modified TM EOS predicts thermodynamic properties with equal or better accuracy than those emerging from the original TM EOS.