The volumetric and thermodynamic functions correlated by Pitzer and co-workers analytically represented with improved accuracy by a modified BWR equation of state. The representation provides a smooth transition between the original tables of Pitzer et al. and more recent extensions to lower temperatures. It is in a form particularly convenient for computer use.

A generalized thermodynamic correlation based on three‐parameter corresponding states

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

The published experimental data for n-alkanes are critically reviewed and the parameters of the Tait equation are given. This equation allows the calculation of smoothed values of liquid density of n-alkanes from pentane to hexadecane over a temperature and pressure range.

Liquid Densities at Elevated Pressures of n-Alkanes from C5 to C16: A Critical Evaluation of Experimental Data

The sound velocity in toluene has been measured up to 2634 bar and at temperatures from 173 to 320 K using the pulse-echo overlap method. The sound velocity in n-heptane has been measured up to 2634 bar and at temperatures from 185 to 310 K by the phase comparison pulse-echo method. The density, the isothermal compressibility, the isobaric thermal expansion and the specific heat at constant pressure of both liquids have been evaluated from the measured sound velocity, following the method of Davis and Gordon. From a comparison of the calculated densities with those obtained previously from direct measurements, it is concluded that the method is very suitable for precise determination of liquid densities under elevated pressures.

The effect of pressure on the sound velocity and density of toluene and n-heptane up to 2600 bar

Primary oil recovery from fractured unconventional formations, such as shale or tight sands, is typically less than 10%. The development of an economically viable enhanced oil recovery (EOR) techni...

A Literature Review of CO2, Natural Gas, and Water-Based Fluids for Enhanced Oil Recovery in Unconventional Reservoirs

Phase Equilibria in Hydrocarbon Systems - Volumetric Behavior of n-Heptane

In spite of the importance of hydrogenation procesing operations in the refining of petroleum there are only limited experimental volumetric and phase equilibrium data concerning mixtures of hydrocarbons and hydrogen. An investigation of the volumetiric and phase behavior of the hydrogen–n-hexane system was therefore undertaken.

The experimental study involved measurements of the specific volume of four mixtures of hydrogen and n-hexane at eight temperatures between 40° and 460°F. for pressures up to 10,000 lb./sq. in In addition, the composition of the gas phase in heterogeneous mixtures was determined at six temperatures within the interval mentioned above for pressures as high as 10,000 lb./sq. in.

Little about this system was found to be qualitatively unusual except that the critical pressure exceeded 10,000 lb/sq. in. at all temperatures below 340°F. As would be expected, the dew-point gas was rather lean in n-hexane for temperatures below 220°F. and at pressures above 100 times the vapor pressure of n-hexane throughout the pressure range covered by this study.

Volumetric and phase behavior in the hydrogen–n‐hexane system

Diffusion Coefficients in Hydrocarbon Systems. The n-Butane-n-Decane System in the Liquid Phase.

The production and refining of petroleum involve many processes in which conditions deviate markedly from equilibrium. For prediction of the behavior of such nonequilibrium systems, information concerning the molecular-transport characteristics of the paraffin hydrocarbons is of practical interest.

Fick diffusion coefficients for methane were measured in the liquid phase of the methane–n-heptane system at temperatures between 40° and 340°F. at pressures up to 3,500 lb./sq. in., but the pressure range was limited at the higher temperatures by approach to the critical state of this binary system.

The measurements obtained confirmed the fact that the Fick diffusion coefficients for methane decrease with an increase in the concentration of this component and increase rapidly with an increase in temperature for a constant composition. These data together with similar information for other binary paraffin hydrocarbon systems indicate that the Fick diffusion coefficients for methane decrease with an increase in the molecular weight of the less volatile component.

H. H. Reamer

Papers

Phase Equilibria in Hydrocarbon Systems - Volumetric Behavior of n-Heptane

Volumetric and phase behavior in the hydrogen–n‐hexane system

Diffusion Coefficients in Hydrocarbon Systems. The n-Butane-n-Decane System in the Liquid Phase.

Diffusion coefficients in hydrocarbon systems: Methane in the liquid phase of the methane–n-heptane system

Duffusion Coefficients in Hydrocarbon Systems. Ethane in the Liquid Phase of the Ethane-n-Decane System.