Determination of derived volumetric properties and heat capacities at high pressures using two density scaling based equations of state. Application to dipentaerythritol hexa(3,5,5-trimethylhexanoate)

2018 ◽  
Vol 20 (5) ◽  
pp. 3531-3542 ◽  
Author(s):  
E. R. López ◽  
O. Fandiño ◽  
D. Cabaleiro ◽  
L. Lugo ◽  
J. Fernández
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Heat Capacities ◽  
Volumetric Properties ◽  
Complex Behavior ◽  
Derived Properties ◽  
Temperature And Pressure

Scaling based EoSs describe the complex behavior of derived properties for broad temperature and pressure ranges from diPEiC9 experimental densities.

scholarly journals Modeling of pure components high pressures densities using CK-SAFT and PC-SAFT equations

2018 ◽  
Vol 83 (3) ◽  
pp. 331-343
Author(s):  
Jovana Ilic-Pajic ◽  
Mirko Stijepovic ◽  
Gorica Ivanis ◽  
Ivona Radovic ◽  
Jasna Stajic-Trosic ◽  
...  
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Model Parameters ◽  
Calculated Density ◽  
Average Percentage ◽  
Pure Compounds ◽  
Density Values ◽  
Temperature And Pressure ◽  
Good Agreement

SAFT equations of state have been widely used for the determination of different thermo-physical and phase equilibria properties. In order to use these equations as predictive models it is necessary to calculate the model parameters. In this work CK-SAFT and PC-SAFT equations of state were applied for the correlation of pure compounds densities in the wide ranges of temperature and pressure (288.15?413.15 K and 0.1?60 MPa, respectively). The calculations of densities for n-hexane, n-heptane, n-octane, toluene, dichloromethane and ethanol, under high pressure conditions, were performed with the new sets of parameters determined in this paper by CK-SAFT and PC-SAFT. Very good agreement between experimental and calculated density values was achieved, having absolute average percentage deviations lower than 0.5 %.

scholarly journals Thermoelastic properties of magnesiowüstite, (Mg1−xFex)O: determination of the Anderson–Grüneisen parameter by time-of-flight neutron powder diffraction at simultaneous high pressures and temperatures

2008 ◽  
Vol 41 (5) ◽  
pp. 886-896 ◽  
Author(s):  
Ian G. Wood ◽  
Lidunka Vočadlo ◽  
David P. Dobson ◽  
G. David Price ◽  
A. D. Fortes ◽  
...  
Keyword(s):  
Equation Of State ◽  
Powder Diffraction ◽  
High Pressures ◽  
Equations Of State ◽  
Time Of Flight ◽  
Neutron Powder Diffraction ◽  
Grüneisen Parameter ◽  
Gruneisen Parameter ◽  
Measured State

The ability to perform neutron diffraction studies at simultaneous high pressures and high temperatures is a relatively recent development. The suitability of this technique for determiningP–V–Tequations of state has been investigated by measuring the lattice parameters of Mg1−xFexO (x= 0.2, 0.3, 0.4), in the rangeP < 10.3 GPa and 300 <T< 986 K, by time-of-flight neutron powder diffraction. Pressures were determined using metallic Fe as a marker and temperatures were measured by neutron absorption resonance radiography. Within the resolution of the experiment, no evidence was found for any change in the temperature derivative of the isothermal incompressibility, ∂KT/∂T, with composition. By assuming that the equation-of-state parameters either varied linearly or were invariant with composition, the 60 measured state points were fitted simultaneously to aP–V–T–xequation of state, leading to values of ∂KT/∂T= −0.024 (9) GPa K−1and of the isothermal Anderson–Grüneisen parameter δT= 4.0 (16) at 300 K. Two designs of simultaneous high-P/Tcell were employed during this study. It appears that, by virtue of its extended pressure range, a design using toroidal gaskets is more suitable for equation-of-state studies than is the system described by Le Godec, Dove, Francis, Kohn, Marshall, Pawley, Price, Redfern, Rhodes, Ross, Schofield, Schooneveld, Syfosse, Tucker & Welch [Mineral. Mag.(2001),65, 737–748].

Equipment for the Experimental Determination of Thermal Properties of Fluids at Elevated Pressures

1972 ◽  
Vol 94 (4) ◽  
pp. 757-764 ◽  
Author(s):  
P. R. Bishnoi ◽  
D. B. Robinson
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Heat Exchanger ◽  
Experimental Determination ◽  
High Pressures ◽  
Heat Capacities ◽  
Compressible Fluids ◽  
Flow Calorimetry ◽  
Elevated Pressures

The available methods for determining the thermal properties of compressible fluids by flow calorimetry are reviewed and an analysis is given for the method of determining heat capacity ratios by passing the fluid at low and high pressures through a heat exchanger. The design of the heat exchanger calorimeter and its associated equipment are described in detail. The performance of the equipment in determining the heat capacities of nitrogen was evaluated at temperatures of 60.2, 75.7, and 150.4 deg C and at pressures up to 2200 psi. The results were compared where possible with those of other workers. Agreement was within about ±0.5 percent which is the anticipated accuracy of the method.

scholarly journals Modeling of density and calculations of derived volumetric properties for n-hexane, toluene and dichloromethane at pressures 0.1-60 MPa and temperatures 288.15-413.15 K

2015 ◽  
Vol 80 (11) ◽  
pp. 1423-1433 ◽  
Author(s):  
Gorica Ivanis ◽  
Aleksandar Tasic ◽  
Ivona Radovic ◽  
Bojan Djordjevic ◽  
Slobodan Serbanovic ◽  
...  
Keyword(s):  
Isothermal Compressibility ◽  
Constant Pressure ◽  
Thermal Expansivity ◽  
Volumetric Properties ◽  
Density Data ◽  
Tait Equation Of State ◽  
Derived Properties ◽  
Temperature And Pressure ◽  
The Difference ◽  
Isobaric Thermal Expansivity

Densities data of n-hexane, toluene and dichloromethane at temperatures 288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work, were fitted to the modified Tait equation of state. The fitted temperature-pressure dependent density data were used to calculate the derived properties: the isothermal compressibility, the isobaric thermal expansivity, the difference between specific heat capacity at constant pressure and at constant volume and the internal pressure, over the entire temperature and pressure intervals specified above. In order to assess the proposed modeling procedure, a comparison of the obtained values for the isothermal compressibility and the isobaric thermal expansivity with the corresponding literature data were performed. The average absolute percentage deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric thermal expansivity: for n-hexane 1.31-4.17%, for toluene 0.71-2.45% and for dichloromethane 1.16-1.61%. By comparing the obtained deviations values with those found in the literature it can be concluded that the presented results agree good with the literature data.

Properties of Refrigerants from Cubic Equations of State

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Viorel Feroiu ◽  
Dan Geana ◽  
Catinca Secuianu
Keyword(s):  
Experimental Data ◽  
Vapor Pressure ◽  
Equations Of State ◽  
Ternary Mixtures ◽  
Volumetric Properties ◽  
Mixing Rules ◽  
Saturation Curve ◽  
Equilibrium Thermodynamic ◽  
Liquid Equilibrium ◽  
Binary And Ternary Mixtures

Vapour � liquid equilibrium, thermodynamic and volumetric properties were predicted for three pure hydrofluorocarbons: difluoromethane (R32), pentafluoroethane (R125) and 1,1,1,2 � tetrafluoroethane (R134a) as well as for binary and ternary mixtures of these refrigerants. Three cubic equations of state GEOS3C, SRK (Soave � Redlich � Kwong) and PR (Peng � Robinson) were used. A wide comparison with literature experimental data was made. For the refrigerant mixtures, classical van der Waals mixing rules without interaction parameters were used. The GEOS3C equation, with three parameters estimated by matching several points on the saturation curve (vapor pressure and corresponding liquid volumes), compares favorably to other equations in literature, being simple enough for applications.

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

On the Negative Excess Isotherms for Methane Adsorption at High Pressure: Modeling and Experiment

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2504-2525 ◽  
Author(s):  
Jing Li ◽  
Keliu Wu ◽  
Zhangxin Chen ◽  
Kun Wang ◽  
Jia Luo ◽  
...  
Keyword(s):  
High Pressure ◽  
Mass Balance ◽  
High Pressures ◽  
Pore Wall ◽  
Void Volume ◽  
Excess Adsorption ◽  
Experimental Conditions ◽  
Accessible Volume ◽  
Adsorbed Phase

Summary An excess adsorption amount obtained in experiments is always determined by mass balance with a void volume measured by helium (He) –expansion tests. However, He, with a small kinetic diameter, can penetrate into narrow pores in porous media that are inaccessible to adsorbate gases [e.g., methane (CH4)]. Thus, the actual accessible volume for a specific adsorbate is always overestimated by an He–based void volume; such overestimation directly leads to errors in the determination of excess isotherms in the laboratory, such as “negative isotherms” for gas adsorption at high pressures, which further affects an accurate description of total gas in place (GIP) for shale–gas reservoirs. In this work, the mass balance for determining the adsorbed amount is rewritten, and two particular concepts, an “apparent excess adsorption” and an “actual excess adsorption,” are considered. Apparent adsorption is directly determined by an He–based volume, corresponding to the traditional treatment in experimental conditions, whereas actual adsorption is determined by an adsorbate–accessible volume, where pore–wall potential is always nonpositive (i.e., an attractive molecule/pore–wall interaction). Results show the following: The apparent excess isotherm determined by the He–based volume gradually becomes negative at high pressures, but the actual one determined by the adsorbate–accessible volume always remains positive.The negative adsorption phenomenon in the apparent excess isotherm is a result of the overestimation in the adsorbate–accessible volume, and a larger overestimation leads to an earlier appearance of this negative adsorption.The positive amount in the actual excess isotherm indicates that the adsorbed phase is always denser than the bulk gas because of the molecule/pore–wall attraction aiding the compression of the adsorbed molecules. Practically, an overestimation in pore volume (PV) is only 3.74% for our studied sample, but it leads to an underestimation reaching up to 22.1% in the actual excess amount at geologic conditions (i.e., approximately 47 MPa and approximately 384 K). Such an overestimation in PV also underestimates the proportions of the adsorbed–gas amount to the free–gas amount and to the total GIP. Therefore, our present work underlines the importance of a void volume in the determination of adsorption isotherms; moreover, we establish a path for a more–accurate evaluation of gas storage in geologic shale reservoirs with high pressure.

Carbon Black. I—A Study of Its Volatile Constituents

1928 ◽  
Vol 1 (3) ◽  
pp. 485-497 ◽  
Author(s):  
C. R. Johnson
Keyword(s):  
Carbon Black ◽  
Volatile Matter ◽  
Original Sample ◽  
Missing Information ◽  
Volatile Constituents ◽  
Vulcanized Rubber ◽  
Rates Of Evolution ◽  
Temperature And Pressure ◽  
The Relationship

Abstract The rates of evolution of gas from carbon black with variation of time, temperature, and pressure have been determined. Complete analyses have been made of five types of carbon black, which involve an organic combustion of the original sample, an organic combustion of the sample after the gases have been removed, a determination of the loss in weight represented by the gases removed, analyses of the gases removed, and finally a complete accounting, or balance, of the carbon in the steps considered. In an attempt to supply some missing information not revealed by the foregoing, some special gas analyses under varying conditions were made. The relationship between the amount and composition of volatile matter evolved from carbon blacks and the properties imparted to vulcanized rubber when compounded with these blacks has been studied.

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