M. J. Hiza

Measurements of the orthobaric liquid densities of methane, ethane, propane, isobutane, and normal butane☆

Abstract The orthobaric liquid densities of the major components of natural gas have been determined with a magnetic suspension densimeter. This paper reports results for methane (105 to 160 K), ethane (100 to 270 K), propane (100 to 288 K), isobutane (115 to 300 K), and normal butane (135 to 300 K). The imprecision of the measured densities is approximately 0.015 per cent; the estimated overall uncertainty is 0.1 per cent at low temperatures and decreases to 0.06 per cent at 300 K. A simple expression has been used to represent the densities as a function of temperature. Comprehensive comparisons with the experimental results of other investigators are presented.

Orthobaric liquid densities and excess volumes for binary mixtures of low molarmass alkanes and nitrogen between 105 and 140 K

Abstract A magnetic suspension densimeter has been used to determine orthobaric liquid densities of gravimetrically prepared binary mixtures of the major components of liquefied natural gas (LNG) i.e. nitrogen, methane, ethane, propane, i-butane, and n-butane, generally between 105 and 140 K. All binary combinations were included in this study, with the exception of nitrogen + i-butane and nitrogen + n-butane. Uncertainties in the reported liquid-mixture densities are discussed in detail. Comparisons are made between excess volumes computed from the present results and comparable values from the literature. It was found that the volumetric properties of binary liquid mixtures of the heavy hydrocarbons (those mixtures not containing nitrogen or methane) are closely approximated by ideal mixing. Some observations are included on the use of excess volumes of the heavy hydrocarbon systems to determine effective molar volumes of n-butane in liquid mixtures below its triple-point temperature. For mixtures containing nitrogen or methane, approximate total vapor pressures are given.

Liquid + vapor equilibria in methane + ethene and in methane + ethane from 150.00 to 190.00 K

Abstract Liquid + vapor equilibrium compositions and pressures are reported for methane + ethane at 160.000 and 180.00 K and for methane + ethene at 150.00, 160.00, 170.00, 180.00, and 190.00 K. Liquid-phase G E values have been estimated from the experimental results. Liquid-mixture G E ( x = 0.5) values are compared with the results of previous investigations at temperatures less than 190 K. For methane + ethane, G E values from 11 of the 16 isotherms analyzed agree within approximately 20 J mol −1 . Of the 13 available methane + ethene isotherms 11 yield G E ( x = 0.5) values that agree within the same limits.

Liquid-vapour phase equilibria in the N2CH4 system from 130 to 180 K

Abstract Isothermal composition measurements for both the equilibrium liquid and vapour phases have been determined for the nitrogen + methane system at eight temperatures between 112.00 and 180.00 K, and at pressures from 1 to 49 atm (1 to 50 bar). The internal consistency of these data is checked by comparing experimental and calculated thermodynamically consistent vapour phase compositions. Derived Henrys constants are used to provide a comparison between these data and those of other investigators.

Orthobaric liquid densities and excess volumes for multicomponent mixtures of low molar-mass alkanes and nitrogen between 105 and 125 K☆

Abstract A magnetic suspension densimeter has been used to determine orthobaric liquid densities of gravimetrically prepared multicomponent mixtures containing the major components of liquefied natural gas, i.e. nitrogen, methane, ethane, propane, isobutane, and normal butane, between 105 and 125 K. These results were obtained to provide a test of the capability of mathermatical models to predict the densities of liquefied natural-gas mixtures. Combinations of the subject components were chosen to provide the most severe test of the models and the possibility of using the measured densities to optimize parameters of the models. Deviations are given between the experimental densities for each mixture and values predicted with an extended corresponding-states model optimized to binary-mixture and pure-component orthobaric liquid densities obtained with the same apparatus. Uncertainties of the present results are discussed in relation to the experimental technique, the knowledge of the compositions of the liquid mixtures, and the comparisons between the experimental and predicted results. Approximate total vapor pressures are also given for each mixture at the temperatures studied.

The solid + vapor and liquid + vapor phase equilibrium properties of neon + krypton☆

Abstract A vapor-recirculation equilibrium cell was used to investigate the solid + vapor and liquid + vapor equilibria and the three-phase curve (equilibrium between solid, liquid, and vapor) for neon + krypton. Gas phase compositions were measured above solid krypton at 100.00, 110.00, and 115.00 K and at pressures to 95 atm (9.6 MPa). Both gas and liquid phase compositions were determined at 120.00, 130.00, 140.00, and 150.00 K at pressures to 106 atm (10.7 MPa). Comparison of cross second virial coefficients from the experimental gas phase results with values obtained from a corresponding states correlation indicate that a deviation parameter from the geometric mean mixing rule for energy parameters of approximately 0.23 is necessary to reconcile the experimental and predicted virial coefficients. Analysis of the Henrys law constants obtained from the liquid phase results indicates a deviation parameter of approximately 0.21.

A review, evaluation, and correlation of the phase equilibria, heat of mixing, and change in volume on mixing for liquid mixtures of methane + propane

The available experimental data for liquid‐vapor equilibria, heat of mixing, and change in volume on mixing for the methane+ethane system have been reviewed and where possible evaluated for consistency. The derived properties chosen for analysis and correlation were liquid mixture excess Gibbs energies, Henry’s constants, and K values. Data sets, selected on the basis of the consistency tests applied, were correlated as functions of temperature and composition to provide internally consistent sets of property values suitable for engineering design calculations.

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.

Status of Thermophysical Properties Data for Pure Fluids and Mixtures of Cryogenic Interest

The importance of thermophysical properties data for fluids involved in cryogenic processing is generally recognized within the engineering community. Cryogenic fluid properties have played significant roles in the development of technologies in such areas as follow: aerospace program, air separation plants, liquefied natural and petroleum gases, fuels, food freezing, ethylene production, ethane recovery, natural gas processing, health and medicine, chemical process plants, and electric power generating systems. With the spiraling inflation in the costs of energy, materials, feedstocks, labor, and environmental compliance and with the increase in capacity of individual plants, there has been a growing awareness of the importance of the accuracy of the thermophysical properties data for fluids in process design and operation. Recently there have been numerous studies1–13 published on the importance of thermophysical properties data of fluids, and many of the examples cited deal with cryogenic systems.1–7 The economic impact of uncertainties in fluid properties data has been presented in many of these papers.1–7

Liquid—vapour equilibria research on systems of interest in cryogenics — a survey

Abstract This survey provides a convenient summary of available data on liquid—vapour equilibria for systems of interest in cryogenics. An annotated bibliography of 392 references has been compiled, current to January 1973. These references have been scanned individually with few exceptions, and cross-indexed by system with notation of extent of data and other significant features. The systems included are those made up of the possible combinations of H 2 (D 2 , HD), N 2 , O 2 , F 2 , CO, H 2 S, He(He 3 ), Ne, Ar, Kr, Xe, and the saturated and unsaturated hydrocarbons through the C 4 s.