In this work, we report high-pressure, high-temperature (HPHT) mixture density and T-p isopleth (bubble (BP) and dew (DP) point) data for hexadecane (HXD) + N2 and heptamethylnonane (HMN) + N2 ...mixtures from ~323 to 523 K and pressures to ~100 MPa. Isothermal, mixture density data for both mixtures are measured in the single–phase region from the BP pressure to ~135 MPa and with ~14–90 mol% N2. A HPHT variable-volume, windowed view cell is used for both density and phase behavior measurements using the synthetic method. Mixture densities are correlated with the modified Tait equation and isothermal BP/DP data are correlated with an Antoine-type equation to allow for reliable interpolation of the data sets. Mixture densities and BP/DP pressures are modeled with the PC-SAFT equation coupled with pure component parameters calculated with two different group contribution methods. Although fairly reasonable predictions of liquid mixture densities are obtained when the binary interaction parameter, kij, is set to zero for both HXD + N2 and HMN + N2 mixtures, a value of kij equal to at least 0.119 is needed for both systems to obtain reasonable predictions of isothermal p-x behavior.
Zinc (II) chloride based deep eutectic solvent (DES) were formed by mixing zinc (II) chloride with phosphoric acid. Fourier‐transform infrared spectroscopy was used to identify any possible shifts ...when the two compounds were assorted, and differential scanning calorimetry (SDT Q600 V20.9 Build 2D) was utilized to evaluate the formation of deep eutectic solvent. Densities,
ρ, and speed of sound, u, of ZnCl2phosphoric acid 1:2.5 with methanol, ethanol, or propanol have been measured at T = (293.15, 303.15, 308.15, and 313.15) K and at atmospheric pressure. Excess molar volumes (
VmE), isentropic compressibilities (
κs), deviation in isentropic compressibility (
Δκs), and intermolecular free length (
Lf) were calculated from the densities, and speed of sound, respectively. To fit the excess molar volumes and deviation in isentropic compressibilities, the Redlich–Kister smoothing polynomial was used. Also, we have used perturbed chain statistical associating fluid theory equation of state (PC‐SAFT EoS) for modeling the densities of the binary mixtures, and Schaaff's collision factor theory (SCFT) and Nomoto's relation (NR) were used for modeling the speed of sounds for the binary mixtures.
•Densities of 3-aminopropan-1-ol and N-(2-hydroxyethyl)morpholine were measured.•Density and speed of sound for 3-aminopropan-1-ol and N-(2-hydroxyethyl)morpholine at ambient condition were ...measured.•Densities were correlated using the PC-SAFT equation of state and modified Tait equation.•Derived thermodynamic properties were predicted by the PC-SAFT and modified Tait equation.
New density data has been reported for 3-aminopropan-1-ol (AP) and N-(2-hydroxyethyl)morpholine (NHEM) at temperatures ranging from (293.15–473.15) K at 19 pressures ranging from (0.1–40) MPa. The experimental measurements were carried out using an Anton Paar high-pressure vibrating tube densimeter with a combined expanded uncertainty of 1 kg m−3 at a 95 % confidence level. Contributions considered in the uncertainty analysis included the impurities in the materials used and apparatus specification. In addition, the density and speed of sound at ambient pressure (81.5 kPa) and temperatures (293.15–343.15) K were measured. The experimental density data were correlated with the modified Tait equation. Values of thermal expansion coefficient (αP ) and isothermal compressibility (κT) were calculated. The work is completed with the modeling of the experimental data using the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EOS). The parameters of the PC-SAFT equation of state, for the pure compounds, were determined by fitting the equation to the liquid PρT experimental data. Thermodynamic properties such as thermal expansion coefficient (αP), isothermal compressibility (κT), isobaric heat capacity (CP), and speed of sound (u) were calculated with the obtain parameters. Good agreement between experimental data and derived properties represented the modeling accuracy with the obtained parameters.
The key to many chemical and energy conversion processes is the choice of the right molecule, for example, used as working fluid. However, the choice of the molecule is inherently coupled to the ...choice of the right process flowsheet. In this work, we integrate superstructure‐based flowsheet design into the design of processes and molecules. The thermodynamic properties of the molecule are modeled by the PC‐SAFT equation of state. Computer‐aided molecular design enables considering the molecular structure as degree of freedom in the process optimization. To consider the process flowsheet as additional degree of freedom, a superstructure of the process is used. The method results in the optimal molecule, process, and flowsheet. We demonstrate the method for the design of an organic Rankine cycle considering flowsheet options for regeneration, reheating, and turbine bleeding. The presented method provides a user‐friendly tool to solve the integrated design problem of processes, molecules, and process flowsheets.
This study aims to use perturbed‐chain statistical associating fluid theory (PC‐SAFT) to describe the phase behavior of systems containing deep eutectic solvents (DESs) and ionic liquids (ILs). The ...DESs are based on tetrabutylammonium chloride and tetrabutylammonium bromide as hydrogen bond acceptors, and levulinic acid and diethylene glycol as hydrogen bond donors in the mole ratio of 1:2 and 1:4, respectively. Predictions of phase equilibria by PC‐SAFT were compared with the results of COnductor like Screening MOdel for Real Solvents (COSMO‐RS) and non‐random two‐liquid (NRTL). In this work, low viscosity ether‐ and pyridinium‐based ILs EnPyNTf2 and CmPyNTf2 were used for vapor–liquid equilibrium systems, while 1‐(2‐methoxyethyl)‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)‐amide and 1‐propyl‐3‐methylimidazolium bis{trifluoromethylsulfonyl}imide with n‐heptane + thiophene and n‐hexane + ethylbenzene were used in the liquid–liquid extraction, respectively. In the last part, the phase behavior of the mixtures of perfluoroalkylalkanes with their linear alkane counterparts was studied and compared with the SAFT‐Mie pair potential.
•CO2 solubility in a mixture of sulfolane and deep eutectic solvent (DES) was investigated.•DES is composed of choline chloride and methyldiethanolamine (MDEA) in a molar ratio of 1 to 6.•The ...vapor-liquid equilibrium of CO2 was measured in a mixture of the present DES with Sulfolane•Gas solubility results were obtained at various temperatures and DES compositions.•PC-SAFT Equation of State was used to predict the phase behavior of DES+ sulfolane (Piperazine)+CO2 systems.
In recent years, releasing post-combustion CO2 into the atmosphere has led to global warming. Air contamination has appeared as a challenge for governments, so several approaches have been used to overcome this issue. So far, physical and chemical solvents have been employed by researchers for CO2 capture. These years deep eutectic solvents (DES) have emerged as an alternative to traditional solvents. In this study, we have investigated a mixture of DES + a physical solvent for the CO2 solubility measurement using a static vapor-liquid equilibrium cell. In this work, the DES was composed of Choline Chloride and MDEA in a molar ratio of 1 to 6 which is blended with sulfolane in weight percentages of 5,10, and 15. We performed the experiments at temperatures of 323.15, 333.15, and 343.15 K and a pressure range of up to 5 MPa. In our previous work, we had already investigated the influence of piperazine on the present DES that led to enhancing CO2 absorption in the mixture, while adding sulfolane to the DES in the present work does not present a positive effect on CO2 solubility in the DES. Enhancing pressure and reducing temperature also led to increasing CO2 solubility. Finally, we modeled the solubility data with the PC-SAFT equation of state. The modeling results were in excellent agreement with the experimental data for DES-CO2, DES-sulfolane-CO2, and DES-piperazine-CO2 systems, so the PC-SAFT EoS successfully estimated the carbon dioxide solubility in the present systems with the absolute average deviation percent of less than unity.
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Hydrogen is a promising alternative to carbon based energy carriers and may be stored in large quantities in subsurface storage deposits. This work assesses the impact of static (density and phase ...equilibria) and dynamic (viscosity and diffusion coefficients) properties on the pressure field during the injection and extraction of hydrogen in the porous subsurface. In a first step, we derive transport properties for water, hydrogen and their mixture using the Perturbed‐Chain Statistical Associating Fluid Theory equation of state in combination with an entropy scaling approach and compare model predictions to alternative models from the literature. Our model compares excellently to experimental transport coefficients and models from literature with a higher number of adjustable parameters, such as GERG2008, and shows a clear improvement over empirical correlations for transport coefficients of hydrogen. In a second step, we determine the effect of further model reduction by comparing our against a much simpler model applying empirical transport coefficients from the literature. For this purpose, hydrogen is periodically injected into and extracted out of a dome‐shaped porous aquifer under a caprock. Our results show that density and viscosity of hydrogen have the highest impact on the pressure field, and that a thermodynamic model like the new model presented here is essential for modeling the storage aquifer, while keeping the number of coefficients at a minimum. In diffusion‐dominated settings such as the diffusion of hydrogen through the caprock, our developed diffusion coefficients show a much improved dependence on temperature and pressure, leading to a more accurate approximation of the diffusive fluxes.
Key Points
We model the phase behavior of pure hydrogen and the binary hydrogen‐water mixture using the Perturbed‐Chain Statistical Associating Fluid Theory equation of state
New entropy scaling relations for the transport properties of hydrogen and water and diffusion coefficients of their mixture are derived
The impact of the newly derived fluid properties is analyzed for a scenario of hydrogen storage in a porous aquifer
This study provides an analysis of the dissolution mechanism of poorly water‐soluble drugs, indomethacin (IND) and naproxen (NAP), from polyvinyl acetate (PVAc) and polyvinylpyrrolidone/vinyl acetate ...64 (PVPVA 64) formulations under the combination of the Perturbed‐Chain Statistical Associating Fluid Theory (PC‐SAFT) and a chemical‐potential‐gradient model. Moreover, the dissolution kinetics of both drugs from these polymeric formulations were modeled in conformity with the in vitro experimental data obtained by means of a rotating disk system (USP II). The combination of the thermodynamic model PC‐SAFT and a chemical‐potential‐gradient model was demonstrated to be an efficient approach to explain the drug dissolution mechanism from the drug/PVAc and PVPVA 64 formulations. These results have implications in reducing experimental time and resources for the sustained dissolution kinetics profile determination without compromising accuracy, in particular for the system of the drug/PVAc formulation when obtaining continuous drug dissolution in this work.
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