Thomas J. Hughes

Thomas J. Hughes
Monash University (Australia) · Department of Civil Engineering, Clayton

Ph.D.

About

49
Publications
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572
Citations

Publications

Publications (49)
Article
The interfacial tension (IFT) between a liquid and a gas is essential in the design of liquid-gas separators as it determines the size of liquid droplets which can become entrained in the gas phase. In liquefied natural gas (LNG) plants, the scrub column is designed to remove components heavier than propane. However, if this column is poorly design...
Article
Heat capacities for single-phase mixtures of the natural gas components methane (1), propane (2) and n-heptane (3) have been determined at temperatures (197 to 421) K and pressures up to 32 MPa using two differential scanning calorimeters with a combined standard uncertainty of (2.0 to 2.6) % (k = 1). In addition, measurements were performed at pre...
Article
Prediction of thermophysical properties for natural gas mixtures close to the mixture's critical point and cricondenbar (the maximum pressure at which two fluid phases can co-exist) is challenging but important as often natural gas processes operate close to these conditions. Here we present a comprehensive study of the viscosity of (CH4 + C3H8 + C...
Article
Full-text available
The prediction of thermophysical properties for hydrocarbon mixtures at high pressures, and conditions near the phase boundary or critical point is challenging. However, natural gas processing applications have an increasing need for reliable property predictions at such conditions. In this work, thermal conductivity measurements of three ternary m...
Article
The liquefaction of natural gas is an energy intensive process, requiring at least 5% of the energy associated with methane's lower heating value. Key to estimating and optimizing these energy requirements are process simulations which rely upon calculated thermophysical properties of the natural gas. In particular, the prediction of thermophysical...
Article
Heat capacities of pure methane (1), propane (2) and n-heptane (3), and binary mixtures of (methane or propane + n-heptane) at n-heptane mole fractions of (0.070 to 0.750), were measured at temperatures (313 to 42) K and pressures (6.00 to 31.10) MPa using a Tian-Calvet-type differential scanning calorimeter with a combined standard uncertainty of...
Article
Isobaric heat capacity data are needed to test and improve thermodynamic models of natural gas over wide ranges of temperature and pressure. Measurements are reported here at temperatures between (184 and 421) K and pressures between (5 and 32) MPa for supercritical mixtures of methane (1) + propane (2) at x1 = 0.950 (±0.005). Estimated relative un...
Article
In this work, the lowest operational temperature of a commercial vibrating tube densimeter (VTD calibrated using robust physically-based model was carefully extended down to 203 K. The VTD was calibrated under vacuum and filled with pure gaseous methane and liquid propane as calibration reference fluids at temperatures from (203 to 423) K and press...
Article
To prevent possible freeze out in the main cryogenic heat exchanger (MCHE) used in liquefied natural gas (LNG) plants, new and accurate phase equilibrium data are required to improve the predictive reliability of existing models, in particular cubic equations of state (EOS). In this work, the vapor-liquid equilibrium (VLE) of a ternary methane + pr...
Article
Thermal conductivities of binary refrigerant mixtures (R125 + R152a), (R125 + R1234ze(E)), (R143a + R1234ze(E)), (R143a + R1234yf), (R1234ze(E) + R1234yf), (R125 + R1234yf), and (R134a + R1234ze(E)) were measured in the homogeneous liquid and vapour phases using the transient hot-wire technique. The measurements span temperatures from (260 to 414)...
Article
The formation and deposition of solids during the cryogenic processing of natural gas is a perennial risk for operators. Several tools are available for predicting the temperatures at which heavy hydrocarbon solids will form in cryogenic processing equipment; of these the Kohn and Luks Solids Solubility Program (KLSSP)from GPA Midstream has become...
Article
Full-text available
Even at trace concentrations the presence of heavy hydrocarbons such as BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) in liquefied natural gas (LNG) production streams poses a significant risk of blockage and eventually plant shutdown. However, although p-xylene has the highest melting temperature of all the BTEX compounds, no data a...
Article
Liquid and vapor viscosities are reported for the binary refrigerant mixtures (R125 + R152a), (R125 + R1234ze(E)), (R143a + R1234ze(E)), (R143a + R1234yf), and (R1234ze(E) + R1234yf). The measurements were made with a vibrating wire viscometer and span temperatures from (252 to 403) K and pressures from (0.9 to 4.0) MPa. The performance of the vibr...
Article
Full-text available
Liquid-phase and vapour-phase densities are reported for the binary refrigerant mixtures (R125 + R1234ze(E)), (R134a + R1234ze(E)), (R143a + R1234ze(E)), (R1234ze(E) + R1234yf), (R125 + R1234yf), (R143a + R1234yf) and (R125 + R152a). The measurements span temperatures from (252 to 294) K and pressures from (0.8 to 4.2) MPa. Vapour-liquid equilibria...
Article
Viscosity measurements of [xCH4 + (1 − x)C3H8] with x = 0.8888 are reported for temperatures between (203 and 424) K and pressures between (2 and 31) MPa using a vibrating wire viscometer clamped at both ends and operating in a steady-state mode. Reliable operation over this range of conditions required a detailed set of calibration and validation...
Article
Accurate predictions and precise control of the allowable water content in CO2-rich fluids are required in large-scale pipeline operations. Especially during transient shut-in and re-start operations, the pressure decrease associated with cooling may cause the CO2-rich mixture to pass through its dew point, producing an aqueous liquid phase. The pH...
Article
The carryover of heavy hydrocarbons into cryogenic heat exchangers, even at low concentrations, represents a significant risk to reliable liquefied natural gas (LNG) production given their propensity to freeze, deposit, and block flow. Calculating blockage risk requires not only freeze-out temperature predictions but also estimates of where solids...
Article
An industrial hydrocarbon dew point detector based on infrared absorption spectroscopy was tested down to a temperature of 243. K and at pressures up to 10. MPa. Dew temperatures were measured isobarically for pure ethane and mixtures of methane + (propane, isobutane, or n-butane). Ethane dew temperatures were within ±0.38. K of the reference equat...
Article
A specialized apparatus designed for visual measurements of solid–liquid equilibrium (SLE) and solid–liquid–vapor equilibrium (SLVE) was constructed and used to measure liquidus (melting) temperatures in binary mixtures of cyclohexane (C6H12) and octadecane (C18H38) across the entire range of composition and at pressures from about (0.004 to 5.3) M...
Article
This paper presents measurements of the enthalpy of vaporization of pure and binary hydrocarbon fluid mixtures using a commercial differential scanning calorimeter (DSC). The DSC was modified to allow the direct measurement of enthalpies of vaporization, ΔvapH, at temperatures as low as 80 K and pressures as high as 10 MPa and was tested by measuri...
Article
Accurate LNG scrub column simulations are challenging, requiring frequent solution of the non-linear equations governing vapor-liquid equilibrium (VLE), material and energy balances for multi-component mixtures. Reliable fluid property predictions at high pressures and low temperatures are thus crucial; however, no high-quality multi-component VLE...
Article
Most of the world’s helium supply is obtained by the cryogenic distillation of natural gas. Modeling the distillation conditions requires equations of state capable of predicting vapor–liquid equilibria over wide ranges of conditions. Equations of state, including cubic equations and multiparameter Helmholtz models, depend on the critical propertie...
Article
Surface tension predictions of hydrocarbon mixtures at vapor-liquid equilibrium are crucially important and used in the design of many unit operations in the production of liquefied natural gas (LNG). Predictive models for surface tension are not well tested for hydrocarbon mixtures at high pressures due to the limited data available at relevant co...
Article
There is a lack of consistency in the literature about how to determine the melting (liquidus) temperature in a hydrocarbon mixture from thermograms recorded by differential scanning calorimetry (DSC). This paper establishes a robust technique for determining liquidus temperatures by DSC by testing the two methods detailed in the literature and ass...
Article
Direct electrical heating (DEH) is one class of active heating technology for subsea pipelines used to prevent hydrate blockages during transient operations. Pipeline heating technologies may also allow for remediation of existing hydrate blockages by raising the local pipeline conditions to a point outside the hydrate equilibrium region prior to r...
Article
The method for the preparation of elemental silicon of sufficient purity for the fabrication of electronic devices is by first converting silicon oxide to silicon-hydrogenchloride compounds, purifying the material as a fluid mixture, and then converting the product to solid silicon. During the purification process a mixture of dichlorosilane (SiH2C...
Article
Formation of water-in-crude oil emulsions is a pervasive problem for crude oil production and transportation. Here we investigate the effectiveness of a comparatively low pressure CO 2 treatment in terms of breaking these water-in-crude oil emulsions. To this end we used unique bench-top Nuclear magnetic resonance (NMR) technology to measure the dr...
Article
High-accuracy equations of state (EOS) are crucial to industrial applications such as natural gas custody transfer and the development of gas processing facilities. The GERG-2008 EOS, which is the ISO standard for calculating the equilibrium properties of natural gas mixtures, has a stated relative uncertainty in density of 0.1% over the temperatur...
Article
Full-text available
The Groupe Européen de Recherches Gazières (GERG) 2008 multi-parameter equation of state (EOS) is considered the reference model for the prediction of natural gas mixture properties. However, the limited quality of thermodynamic property data available for many key binary mixtures at the time of its development constrained both its range of validit...
Article
The viscosity of {xCH4 + (1 - x)C4H10} with x = 0.9484 has been measured at temperatures and pressures in the range (200 to 423) K and (2 to 30) MPa, respectively, corresponding to densities between (20 and 371) kg·m-3. The measurements were made using a vibrating-wire-viscometer with the wire clamped at both ends and operated in steady-state mode...
Article
A specialized cell designed for vapor liquid equilibrium (VLE) measurements at cryogenic temperatures and high pressures was used to measure new (p,T,x,y) data for binary mixtures of methane + ethane, + propane, + 2-methylpropane (isobutane), and + butane from (203 to 273) K at pressures up to 9 MPa. A literature review of VLE data for these binary...
Article
A vibrating wire instrument, in which the wire was clamped at both ends, was used to measure the viscosity of {xCO2 + (1 − x)CH4} with x = 0.5174 with a combined uncertainty of 0.24 μPa · s (a relative uncertainty of about 0.8 %) at temperatures T between (229 and 348) K and pressures p from (1 to 32) MPa. The corresponding mass density ρ, estimate...
Article
New isothermal pTxy data are reported for (methane + benzene) and (methane + methylbenzene (toluene)) at pressures up to 13 MPa over the temperature range (188 to 313) K using a custom-built (vapor + liquid) equilibrium (VLE) apparatus. The aim of this work was to investigate literature data inconsistencies and to extend the measurements to lower t...
Article
The viscosity of {xCH(4) + (1 - x)C3H8} with x = 0.949 was measured at temperatures between (200 and 423) K and pressures in the range (10 to 31) MPa using a vibrating-wire-viscometer with the wire clamped at both ends and operating in steady-state mode. Over these conditions the fluid mass density, which was calculated from the measured temperatur...
Article
The simulation of carbon capture unit operations often involves predicting the vapor liquid equilibrium (VLE) for mixtures containing polar, non-polar and quadrupolar compounds. In this work, we investigate how well a simple cubic equation of state (EOS) can predict the results of new low temperature, high-pressure VLE measurements of the ternary m...
Article
We present a clamped vibrating-wire instrument and the associated methods of measurement and analysis that enabled gas-mixture viscosity measurements at densities up to 110 kg·m–3 with a standard uncertainty of 0.09 μPa·s, which is a relative uncertainty of 0.60 %. The vibrating-wire was clamped at both ends and operated in the steady-state mode to...
Article
Isobaric heat capacity cp measurements are reported at temperatures between (108 and 168) K for liquid mixtures of CH4 (1) + C3H8 (3) at x1 ≈ 0.8 and p ≈ 5 MPa; CH4 (1) + C4H10 (4) at x1 = 0.96, 0.88, and 0.60 and p ≈ 5 MPa; and a five-component mixture that is similar in composition to a commercial mixed refrigerant at p = (1.0 and 5.0) MPa. Measu...
Article
A commercial differential scanning calorimeter (DSC) was adapted to allow accurate isobaric heat capacity, cp, measurements of cryogenic, high-pressure liquids. At (subcritical) temperatures between (108.15 and 258.15) K and pressures between (1.1 and 6.35) MPa, the standard deviation in the measured cp values was 0.005·cp for methane, 0.01·cp for...
Article
The enhanced recovery of natural gas by the injection and sequestration of CO2 is an attractive scenario for certain prospective field developments if the risks of gas contamination or early CO2 breakthrough can be assessed reliably. Simulations of enhanced gas recovery (EGR) scenarios require accurate dispersion parameters at reservoir conditions...
Article
Semiclathrate hydrates (SCH), containing organic salts, typically tetraalkylammonium based, have vacant cages that can be occupied by gas molecules, and some exhibit melting temperatures at atmospheric pressure of greater than 300 K. The aim of this work was to investigate the p, T phase equilibria of the SCH former tetraisopentylammonium fluoride,...
Article
Several previous measurements of the isobaric heat capacity of the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([Hmim][Tf2N]) differ relative to the IUPAC recommended value by ± 8 %. Specifically, the results obtained by differential scanning calorimetry (DSC) showed relative difference from each other and from values...
Article
In studying the relative dissociation times of structure I (sI) and structure II (sII) gas hydrates prepared from methane + ethane mixtures, X-ray diffraction analysis indicated the simultaneous presence of both hydrate structures at conditions where only one hydrate structure was expected. The aim of this work was to develop a model describing the...
Article
Full-text available
Gas hydrates are known to form plugs in pipelines. Hydrate plug dissociation times can be predicted using the CSMPlug program. At high methane mole fractions of a methane + ethane mixture the predictions agree with experiments for the relative dissociation times of structure I (sI) and structure II (sII) plugs. At intermediate methane mole fraction...
Article
Full-text available
The potential for over-pressurization of a pipeline during hydrate plug remediation by direct electrical heating (DEH) for hydrate plugs containing and/or in the presence of liquid and gaseous hydrocarbon phases is being investigated. The two most relevant questions to address are: 1) under what conditions is it safe to heat electrically an oil-fil...

Projects

Project (1)
Project
Solid-Liquid Equilibrium analysis of LNG mixtures