Nitrogen and oxygen are the main components of air. Liquid nitrogen is an alternative to fossil fuels. However, little attention has been paid to this energy resource. Liquid oxygen is not a fuel in itself, however, it can be used as an oxidizer to run vehicles. In this respect, gas hydrate technology can be of interest, as applicable media for nitrogen/oxygen transport or nitrogen/oxygen separation

In this work, we have derived rigorous expressions for the thermodynamic description of the solvation behavior of a model solute in highly-compressible environments of a real solvent, in order to address the question posed in the title of this manuscript. Toward that end, we first provide the essential statistical thermodynamic foundations to support a fundamentally-based approach for the determination

The purpose of this work is to study the dissolution behavior of chlorfenapyr in different solvents, and to screen out the solvents in which chlorfenapyr is purified by crystallization. In this work, the solubility of chlorfenapyr in five mono-solvents (methanol, ethanol, isopropanol, cyclohexane and ethyl acetate) and two mixed solvents (ethanol + ethyl acetate and isopropanol + ethyl acetate) was

R1234yf and R1234ze(E) as green refrigerants have attracted wide attention. Phase behavior of refrigerant/oil and oil circulating mass fraction are critical to the performance and reliability of refrigeration systems. Using isochoric saturation method, the solubilities were measured for R1234yf and R1234ze(E) in POE75 from 278.15 to 348.15 K. The pressure–enthalpy–vapor quality diagrams for pure refrigerants

This paper is a continuation of study focused on thermodynamic properties of isomeric and quasi-isomeric ionic liquids. In this work 5 novel ionic liquids were synthesized, namely 1-(2-(2-ethoxyethoxy)ethyl)-3-alkylimidazolium bis(trifluoromethylsulfonyl)imides, where the alkyl stands for different C5 substituents. These species were characterized as to their isobaric molar heat capacity and thermal

We here report a three-parameter correlation for the temperature T dependent thermal conductivity λ of different kinds of saturated liquids including n-alkanes, refrigerants and others such as argon and nitrogen. The correlation is proven to be more accurate than other known correlations. Compared with the REFPROP data in NIST, the proposed correlation reproduces the corresponding data with the average

A comparative study is conducted to find that there are significant prediction deviations of single liquid desiccants vapor pressure at high concentration and regeneration temperature (high temperature) based on existing typical models. Some factors affecting water activity are not taken into account in these models, and they become more significant at high temperature and high concentration. This

One of the major issues in the oil industry is asphaltene precipitation. Modeling asphaltene precipitation is still considered as a complex problem due to various characteristics of different heavy components existing in the crude oil. Thermodynamic models have been found as accurate models for studying asphaltene precipitation in the past few years and a great deal of effort has been devoted to model

The paper is the first of a series of two articles on molecular models for alkanes with air components and combustion products. This article reports simulations of the vapor-liquid equilibrium phase diagram for mixtures of linear hydrocarbons with nitrogen, carbon dioxide and water. We consider four alkanes: methane, propane, octane and dodecane as characteristic components of natural gas, liquefied

The adsorption equilibria of propylene glycol monomethyl ether acetate (PGMEA), a major volatile organic compound (VOC) used in the semiconductor industry, on activated carbon were measured in the presence of supercritical carbon dioxide (scCO2) at temperatures from 313 K to 353 K and pressures from 10.0 MPa to 20.0 MPa. The amount of adsorbed PGMEA considerably depended on the pressure and temperature

An equation of state (EOS) in the form of Helmholtz free energy for fluid mixtures was improved by using four mixing parameters. It can calculate the pressure-volume-temperature-composition (PVTx) and vapor-liquid equilibrium (VLE) properties of the CO2–N2 fluid mixture. This EOS is based on highly accurate EOSs of pure CO2 and N2 fluids and contains a simple generalized departure function of Lemmon

The solubility of methane in water decreases when a small amount of salt is present. This is usually denoted as the salting out effect (i.e., the methane is expelled from the solution when it contains small amounts of salt). The effect is important, for instance the solubility is reduced by a factor of three in a 4 m (mol/kg) NaCl solution. Some years ago we showed that the salting out effect of methane

Asphaltene deposition is a common flow assurance problem in the oil and gas industry. During oil production, changes in pressure, temperature, and composition may induce precipitation as asphaltenes become unstable in the oil. Precipitated asphaltenes can then deposit on the inner walls of the production tubing and restrict or even completely block the flow of oil. In this work, we propose a novel

We present a novel approach for the calculation of the Krichevskii parameter AKr of solutes in dilute mixtures according to a universal thermodynamic expression that links the solute-solvent intermolecular asymmetry, as described by the Henry's law constant of the solute species in a pure solvent, to the desired AKr. The derived expression obeys two key thermodynamic constraints, i.e., corresponding

The stable phase equilibrium data of Mg2+, NH4+//Cl−, SO42−−H2O quaternary interaction system and its four ternary subsystems at 363.15 K were determined by isothermal dissolution equilibrium method, and the corresponding stable phase diagrams of the above systems were plotted. According to the phase diagram, there are seven solid phase crystalline regions, which correspond to MgSO4·(NH4)2SO4·6H2O

In this work we have developed an equation for correlating the kinematic viscosities of binary mixtures of ionic liquids with organic solvents and with water in a wide range of temperature at atmospheric pressure. The new correlation uses the molecular surface fraction as composition variable. The performance of the new equation to correlate the viscosity has been tested using 5746 literature viscosity

A general formulation of association theory is presented which, unlike Wertheim's association theory as proposed in the Statistical Associating Fluid Theory, allows association strengths to vary with different sizes of oligomer. It is shown that association theory is governed by a few simple relationships which apply in all cases. The formulation is compatible with any equation of state. Potential

The purpose of this research is the study of aqueous two-phase systems (ATPSs) composed of (1-propanol or 2-propanol + choline bitartrate + water) at T = (298.15, 308.15 and 318.15) K and atmospheric pressure (≈85 kPa). The use of these systems for separation of acetaminophen, as a model drug was also examined. Partitioning of acetaminophen was also studied in aqueous two-phase systems containing choline

The phase equilibrium and thermodynamic properties of potassium dihydrogen phosphate (KDP) in the binary water-ethanol system are of critical significance for the salting-out crystallization of KDP production using ethanol as anti-solvent. The solubility of KDP in water-ethanol solvent was determined by the static equilibrium method under constant pressure at temperatures ranging from 293.2 to 323

In this work, the equilibrium conditions of xenon hydrates have been measured within wide pressure and temperature ranges. Various experimental equipment have been used for this purpose, namely the tensimeter, the Cailletet apparatus, and the high-pressure autoclave. A number of three-phase equilibrium data points were measured for liquid water-hydrate-vapor (Lw-H-V) and the ice-hydrate-vapor (I-H-V)

Hydrodynamic simulation of fluids in vessels is often based on the internal energy (U), volume (V), and the number of moles of all components (reN=N1,N2,…,Nn) as the working variables to determine the thermodynamic state by finding the global maximum of entropy. The procedure of finding the equilibrium state may be divided into two steps: stability analysis and phase-split computations. Stability analysis

The large availability of glycerol on the market and EU directives in the field of automotive fuels prompt Eni S.p.A to develop a technology for producing biofuels from glycerol. This work focuses on determining isobaric vapor-liquid equilibrium data at different pressures of binary systems constituted by 3-ethoxy-1,2-propanediol, an intermediate product, and some of the other compounds involved in

The purpose of this study was to measure and model isothermal binary vapour-liquid equilibrium (VLE) data for the water + butane-1,4-diol/butane-2,3-diol system to aid in the design of separation processes. P-T-x-y phase equilibrium measurements were determined at three temperatures from approximately 353 to 373 K, utilizing a dynamic-analytic apparatus. The vapour-liquid phase equilibrium data were

Images of water clusters have been reported recently. In this paper, the dynamics of water clusters when dissolving crystals of sodium chloride is studied under a microscope. Images of water clusters have two different colours, a dark outer layer and a shallow inner layer as a water cluster is composed of two phases. Since the experiments were conducted at room temperature there should be no solid

The hydrogen bonding structure of water and its dynamics in aqueous ammonia solution is investigated by using classical molecular dynamics simulations. We have considered eight different mole-fraction of ammonia, ranging from xNH3 = 0.02 to 0.30, and the pressure variation is carried out on the concentrated ammonia solution (xNH3=0.30), ranging from P = 0.1 MPa to 800 MPa, at 293K. The radial distribution

Application of classical density functional theory in cylindrical coordinates requires a fast Hankel transform algorithm of order zero and its inverse, when the involved convolution integrals are solved in Fourier space. Vector-valued fundamental measure theory requires a fast Hankel transform of first order and its inverse. Compared to naïve real space convolution, this not only reduces complexity

A semi-empirical power law-based theory has been developed to model the crystallization kinetics in precipitating systems for CO2 capture. A more reliable activity-based theory and simplified concentration-based crystallization kinetics have also been derived for a gas-liquid-solid system in which CO2 evolution might be unavoidable during the experiments performed to determine crystallization kinetics

Few studies have been reported on optimizing the energy consumption of the CO2 capture process. Thus neglecting that the scale of industrial application of adsorption technology depends on the energy consumption of the process. In this work, 98 different types of porous carbon materials were constructed. The quantitative relationship between the material properties and structure was established through

This study reports the newVLE data of n-hexadecane in pure propane at 403 Kand in the supercritical solvent mixture (0.527 propane+0.473 n-butane mole fraction) at 403 K, 423 K, and 443 K over the pressure range from (1.22–6.31) MPa. The measurements were made using a high-temperature and high-pressure optical cell.The combined expanded uncertainty of the temperature, pressure, and concentration measurements

Thermodynamically consistent phase equilibrium data at 101.3 kPa and boiling conditions were determined for the ternary systems water + Na2SO4 + 1-propanol, water + Na2SO4 + 2-propanol, water + K2SO4 + 1-propanol and water + K2SO4 + 2-propanol. In contrast to the systems with Na2SO4, the salting-out effect of K2SO4 was not sufficient to split the miscible propanol + water mixture into two liquid phases

Surfactant-laden liquid/liquid interfaces mediate numerous chemical processes, from commercial applications of microemulsions to chemical separations. Classical molecular dynamics simulation is a prevalent method for studying microscopic and thermodynamic properties of such interfaces. However, the extent to which these features can be reliably predicted, and the variations in predicted behavior, depend

This paper presents an experimental and modeling study of the systems pure AMP, AMP/H2O and AMP/CO2/H2O. All available data in the literature is collected and new experimental data for the ternary AMP/CO2/H2O system are presented. Modeling was performed using an Antoine model for the pure component VLE and an NRTL model for the binary AMP/H2O system. The parameters in the two model were fitted together

The hydrogen sulfide (H2S) absorption capacity of a 70 wt% aqueous methyldiethanolamine (MDEA) solution was investigated in a static-analytic apparatus at temperatures of 283, 353 and 393 K and pressures of 2000, 6000 and 10000 kPa in the presence of methane. New experimental data were also produced for a 50.1 wt% aqueous MDEA at 323 K and pressures of 500 and 3000 kPa as part of the apparatus validation

New isothermal vapor–liquid equilibrium (VLE) data for the carbon dioxide + 2-octanol system are measured at five temperatures between 298.15 and 333.15 K and pressures up to 103 bar. The experimental method used is the static-analytical one with phases sampling. The new experimental data obtained in this study are compared with all available literature data and discussed. The new and all available

Perturbed-Chain Statistical Associating Fluid Theory Equation of State (PC-SAFT EoS) requires cross interaction parameter for each binary pair in the mixture. For real mixtures, these parameters should be corrected by binary interaction coefficients (kij's). The values of kij's are tuned by an optimization method in order to minimize the deviation from equilibrium data. The Particle Swarm Optimization

In this study, the phase transition of confined argon in slit by Lennard-Jones (12-6) potential for fluids-fluids and walls-fluids interactions is investigated. The effects of temperature, pressure, and distance between the two walls on the phase transition were investigated by using the molecular dynamics simulation and LAMMPS software. It was found that wall distances had a significant effect on

An algorithm is presented for the estimation of the UNIQUAC interaction parameters for liquid-liquid equilibrium of ternary systems. The algorithm is based on two optimization levels. In the inner level the algorithm performs the minimization of an objective function based on the isoactivity conditions. The outer level aims to minimize the error between calculated and experimental compositions. The

This work is a continuation of the investigations on desulfurization processes, by assessing the applicability of two ionic liquids (ILs), 1-butyl-1-methylpiperidynium dicyanamide, [BMPIP][DCA] and tri-iso-butylmethylphosphonium tosylate, [Pi4,i4,i4,1][TOS], for the separation of thiophene from octane, or hexadecane. The latter two components are used as model substances of the fuel stream. Experimental

Wax precipitation is a major flow assurance issue for petroleum production, oil blending, downstream processing, and oil products usage. While numerous thermodynamic models have been proposed to calculate wax appearance temperature (WAT) and precipitation profile at temperatures below WAT, the existing models are correlative in nature and fail to comply with phase behavior experimentally observed for

In order to develop a new process to eliminate acid gases from natural gas, it is important to consider phase equilibrium properties. New solid-liquid equilibrium data were determined concerning the ternary system CO2 + H2S + CH4. The experimental technique is based on visual synthetic method. The new experimental data were compared to predictions given by the Predictive Peng-Robinson equation of state

A group contribution method is developed for estimating the electrical conductivity of ionic liquids (ILs). Based on 1578 collected experimental data covering 57 ILs in a wide range of temperature (248.05–468.15 K) and electrical conductivity (0.0017–9.1670 S m−1), the parameters of each group (cation, anion, substituent) in the method are optimized. A deterministic algorithm-based on multivariate