E. D. Sloan

Vapor-liquid equilibria in the carbon dioxide-ethane system

Abstract Vapor—liquid equilibria for the binary system carbon dioxide-ethane were measured at eight temperatures from 207 to 270 K. The data were modeled with three equations of state: the Peng-Robinson, the Soave-Redlich-Kwong, and the Fuller modification of the Soave-Redlich-Kwong. All of the equations gave satisfactory results with the use of one binary interaction parameter. However, the interaction parameters varied substantially with temperature.

Vapor-liquid equilibria in the nitrogen + carbon dioxide + ethane system

Abstract Vapor-liquid equilibria (VLE) for the binary systems nitrogen + carbon dioxide, nitrogen + ethane, and carbon dioxide + ethane were measured at 220 K and 270 K. Measurements were also made on the carbon dioxide + ethane system at six other temperatures from 207 to 263.15 K. The ternary system was studied at 220 K and 0.803, 4.000, and 9.000 MPa and at 270 K and 3.450, 6.000, 8.400, 9.000, and 9.600 MPa. The data were modeled with both the Peng-Robinson (1976) and Soave-Redlich-Kwong (1972) equations of state. Both equations fit the data well at low pressures but failed near the critical regions of the binary and ternary systems.

The melting curve of tetrahydrofuran hydrate in D2O

Melting points for the tetrahydrofuran/D2O hydrate in equilibrium with the airsaturated liquid at atmospheric pressure are reported. The melting points were measured by monitoring the absorbance of the solution. Overall, the meltingpoint phase boundary curve is about 2.5 K greater than the corresponding curve for the H2O hydrate, with a congruent melting temperature of 281±0.5 K at a D2O mole fraction of 0.936. The phase boundary is predicted to within 5% if the assumption is made that the THF occupancy in the D2O and H2O hydrates is the same. We measure an occupancy of 99.9%. The chemical potential of the empty lattice in D2O is estimated to be 5% greater than in H2O.

A computer-controlled transient needle-probe thermal conductivity instrument for liquids

A computerized system utilizing the transient needle-probe technique has been developed for thermal conductivity measurements on solids and liquids. Thermal conductivities are determined to an accuracy of better than 5%. The instrument is unique in that it uses “off the shelf” components such as a personal computer and analog-to-digital conversion devices, together with software developed in our laboratory. The initial expense and time required to begin measurements are less than 20% of those for normal transient hot-wire measurements. Typical results are presented for liquid tertiary butyl alcohol, 1-methylnaphthalene, and glycerin.

A Review and Evaluation of the Phase Equilibria, Liquid‐Phase Heats of Mixing and Excess Volumes, and Gas‐Phase PVT Measurements for Nitrogen+Methane

The available experimental data for vapor–liquid equilibria, heat of mixing, change in volume on mixing for liquid mixtures, and gas‐phase PVT measurements for nitrogen+methane have been reviewed and where possible evaluated for consistency. The derived properties chosen for analysis and correlation were liquid mixture excess Gibbs free energies, and Henry’s constants.

Thermal conductivity and heat capacity of synthetic fuel components

As part of a group contribution study on the liquid thermal conductivity of synthetic fuel components, experiments were performed to study the effects of dimethyl and ethyl-group additions to cyclohexane. A transient hot-wire apparatus was used to measure the thermal conductivity of these three fluids between ambient pressure and 10.4 MPa over a temperature range of 300 to 460 K. Thermal conductivities measured with this instrument have been assigned an accuracy of ±2% based upon a standard deviation comparison with a toluene standard established by Nieto de Castro et al. (1986). The thermal conductivities and excess thermal conductivities of the naphthenes investigated have been successfully linearized by plotting the data versus reduced density exponentiated to the power of five. By using data previously reported by Perkins (1983) and Li et al. (1984), this linear reduced density method is demonstrated for methyl, dimethyl, and ethyl additions to cyclohexane, as well as methyl and dimethyl additions to benzene. The naphthenes have been shown to have similar intercepts, with slope changes dependent upon the functional group attached to cyclohexane. The aromatics have a less pronounced slope change with additional functional groups attached to the benzene base. This instrument was also used to determine heat capacities, via the thermal diffusivity, to within ±10%.