A new equation of state for the thermodynamic properties of natural gases, similar gases, and other mixtures, the GERG-2008 equation of state, is presented in this work. This equation is an expanded version of the GERG-2004 equation. GERG-2008 is explicit in the Helmholtz free energy as a function of density, temperature, and composition. The equation is based on 21 natural gas components: methane, nitrogen, carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, hydrogen, oxygen, carbon monoxide, water, hydrogen sulfide, helium, and argon. Over the entire composition range, GERG-2008 covers the gas phase, liquid phase, supercritical region, and vapor–liquid equilibrium states for mixtures of these components. The normal range of validity of GERG-2008 includes temperatures from (90 to 450) K and pressures up to 35 MPa where the most accurate experimental data of the thermal and caloric properties are represented to within their accura...

The GERG-2008 Wide-Range Equation of State for Natural Gases and Other Mixtures: An Expansion of GERG-2004

In a preceding project, functional forms for “short” Helmholtz energy equations of state for typical nonpolar and weakly polar fluids and for typical polar fluids were developed using simultaneous optimization. In this work, the coefficients of these short forms for the equations of state have been fitted for the fluids acetone, carbon monoxide, carbonyl sulfide, decane, hydrogen sulfide, 2-methylbutane (isopentane), 2,2-dimethylpropane (neopentane), 2-methylpentane (isohexane), krypton, nitrous oxide, nonane, sulfur dioxide, toluene, xenon, hexafluoroethane (R-116), 1,1-dichloro-1-fluoroethane (R-141b), 1-chloro-1,1-difluoroethane (R-142b), octafluoropropane (R-218), 1,1,1,3,3-pentafluoropropane (R-245fa), and fluoromethane (R-41). The 12 coefficients of the equations of state were fitted to substance specific data sets. The results show that simultaneously optimized functional forms can be applied to other fluids out of the same class of fluids for which they were optimized without significant loss of a...

Short Fundamental Equations of State for 20 Industrial Fluids

A compendium of phase change enthalpies published in 2010 is updated to include the period 1880–2015. Phase change enthalpies including fusion, vaporization, and sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds. Part 1 of this compendium includes organic compounds from C1 to C10. Part 2 of this compendium, to be published separately, will include organic and organometallic compounds from C11 to C192. Sufficient data are presently available to permit thermodynamic cycles to be constructed as an independent means of evaluating the reliability of the data. Temperature adjustments of phase change enthalpies from the temperature of measurement to the standard reference temperature, T = 298.15 K, and a protocol for doing so are briefly discussed.

Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2015. Part 1. C1-C10

Extension of the PPR78 model (Predictive 1978, Peng-Robinson EOS with temperature dependent kij calculated through a group contribution method) to systems containing naphtenic compounds

Determination of the excess volumes of (cyclohexane + benzene) between 293.15 and 303.15 K by use of a vibrating densimeter

Determination of excess volumes in cyclohexane + benzene and + n-hexane with a vibrating-tube densimeter

(Solid + liquid) and (vapor + liquid) phase equilibria and excess enthalpies for (benzene + n-tetradecane), (benzene + n-hexadecane), (cyclohexane + n-tetradecane), and (cyclohexane + n-hexadecane) at 293.15, 298.15, and 308.15 K. Comparison of GmE calculated from (vapor + liquid) and (solid + liquid) equilibria

Excess volumes of n-hexane +n-heptane, +n-octane, +n-nonane, and +n-decane at 283.15, 298.15, and 313.15 K

(Solid+liquid) and (vapor+liquid) phase equilibria and excess enthalpies for (benzene+n-tetradecane), (benzene+n-hexadecane), (cyclohexane+n-tetradecane), and (cyclohexane+n-hexadecane) at 293.15, 298.15, and 308.15 K

Excess enthalpies and excess volumes were determined over the entire composition range and at the three temperatures 283.15,298.15 and 313.15 K for mixtures of n-hexane with the three isomeric hexanes: 2- methylpentane, 3-methylpentane and 2,3-dimethylbutane. The excess enthalpies were measured with a microflow calorimeter and the excess volumes with a vibrating-tube densimeter. The results are correlated with the molecular shape of the isomeric hexane.

J.R Goates

Papers

Determination of excess volumes in cyclohexane + benzene and + n-hexane with a vibrating-tube densimeter

Excess volumes of n-hexane +n-heptane, +n-octane, +n-nonane, and +n-decane at 283.15, 298.15, and 313.15 K

(Solid+liquid) and (vapor+liquid) phase equilibria and excess enthalpies for (benzene+n-tetradecane), (benzene+n-hexadecane), (cyclohexane+n-tetradecane), and (cyclohexane+n-hexadecane) at 293.15, 298.15, and 308.15 K

Excess enthalpies and excess volumes for n-hexane + 2-methylpentane, + 3-methylpentane and + 2,3-dimethylbutane at 283.15, 298.15 and 313.15 K