Erratum to “Henry's law constants of methane, nitrogen, oxygen and carbon dioxide in ethanol from 273 to 498 K: Prediction from molecular simulation” [Fluid Phase Equilib. 233 (2005) 134–143

Henry’s law constants of methane, nitrogen, oxygen and carbon dioxide in ethanol from 273 to 498 K: Prediction from molecular simulation

Determination of Henry's law constants through transition matrix Monte Carlo simulation

Erratum to Henry’s law constants of methane, nitrogen, oxygen and carbon dioxide in ethanol from 273 to 498 K: Prediction from molecular simulation [Fluid Phase Equilib. 233 (2005) 134–143

Configurational-bias Monte Carlo simulations in the Gibbs ensemble were used to calculate Henry’s law constants, Ostwald solubilities, and Gibbs free energies of transfer for oxygen, nitrogen, methane, and carbon dioxide in ethanol at 323 and 373 K. These three solubility descriptors can be expressed as functions of mechanical properties that are directly observable in the Gibbs ensemble approach, thereby allowing for very precise determination of the descriptors. Additionally, the Henry’s law constants of multiple solutes can be computed from a single simulation. Most of the simulations were carried out for systems containing 1,000 solvent and up to 8 solute molecules, and further simulations using either 500 or 2,000 solvent molecules point to negligible system size effects. A comparison with experimental data shows that the united-atom version of the transferable potential for phase equilibria force field yields Henry’s law constants that reproduce well the differences between the four solutes and the changes upon increase of the temperature.

We present a novel molecular-based approach for the determination of the osmotic second virial coefficients of gaseous solutes in dilute binary solutions, according to a recently proposed molecular thermodynamic formalism of gas solubility [A. A. Chialvo, J. Chem. Phys. 148, 174502 (2018) and Fluid Phase Equilib. 472, 94 (2018)]. We discuss relevant solvation fundamentals and derive new expressions including (i) the relations among infinite-dilution solvation quantities leading to a novel self-consistent route to the calculation of the osmotic second virial coefficients, (ii) the new microstructural interpretation of the resulting osmotic second virial coefficients based on Kirkwood-Buff integrals, the unambiguous discrimination between short- and long-range contributions, and their limiting behavior as the solvent approaches its critical conditions, (iii) new rigorous expressions for the calculation of the osmotic second virial coefficients using standard reference thermodynamic data, and (iv) their underlying interdependence based on the constrained state variable invoked in the density expansion. We then invoke the proposed formalism to shed some light on the inaccuracies behind current calculations of osmotic second virial coefficients from molecular theory and simulation as well as macroscopic correlations. To advance the microscopic understanding and illustrate the functional relationship between the osmotic second virial coefficients, Henry's law constant, and the solute-solvent intermolecular asymmetry as a source of solution non-ideality, we use data for the microstructural and thermodynamic behavior of infinitely dilute Lennard-Jones systems obtained self-consistently via integral equations calculations. The newly derived relationships leading to the proposed formalism offer novel routes for the accurate determination of osmotic second virial coefficients of any type of solutes in dilute solutions regardless of the type and nature of the intermolecular interactions. However, for illustration purposes in the current work, we dealt with aqueous solutions of simple gases to exploit the abundance of standard thermodynamic data for the orthobaric Henry's law constant and solute distribution coefficients, as well as the availability of results from molecular-based calculations and macroscopic correlations.

In recent years, substantial progress has been made in the theoretical treatment of hydrocarbon dissolution in water, near the critical point of water (374 °C). At these temperatures, water becomes a solvent for gases including the lower hydrocarbons, and possibly, the higher hydrocarbons. The SAGD process is currently the only viable method for in situ recovery of Canada's Athabasca oil sands deposit, a deposit of high viscosity oil in unconsolidated sand. Recent studies have sought to understand modifications at lower steam pressures and gas injection. Most recently, the idea of solvent co-injection has been under discussion. In the present paper, the predictive capabilities that have been developed for gas production in the SAGD process are studied in conjunction with the chemical kinetics and mechanisms of solvolytic reactions. The reactions that produce hydrogen sulphide and carbon dioxide, generally referred to by the name "aquathermolysis, are thought to be solvolytic reactions by their nature. The results of this work suggest strongly that the production of the acid gases, hydrogen sulphide, and carbon dioxide will be suppressed in SAGD operations if a solvent is co-injected. The work has implications for the need for sulphur recovery plants in SAGD projects that are considered for solvent co-injection. Recently published thermodynamic data have made possible the prediction of individual solvent component production or retention in the steam zone. Introduction In 2001, Thimm(1) proposed that gas production in SAGD proceeds via a dissolution mechanism. Gases are dissolved in the produced liquids, and break out of solution in the wellbore and facilities. There has been no case reported so far where it is necessary to assume free gas production in SAGD in order to account for observed gas production or composition. The rationale is as follows. The distribution coefficient (K-value) of a solute gas in equilibrium with a solvent is given by: Equation (Available In Full Paper) In this form, the unit of the Henry's Law coefficient is that of pressure, as is evident from inspection. For the purpose of this work, all Henry's Law constants are given in units of MPa. The equation shows that the K-values are related to the Henry's Law constant. Determination of Henry's Law Constants Henry's Law coefficients for gases in water normally follow a power law known as the Valentiner Equation: Equation (Available In Full Paper) However, at elevated temperatures, this equation begins to fail at about 175 °C, and could only be used for the lowest steam pressure situations. Above this temperature, deviations become progressively larger, because an asymptotic behaviour of the Henry's Law constant near the critical point of water makes an increasingly important contribution. Above 175 °C, the specific volume of water begins to fall significantly from the normal 55.56 mole/L, and Harvey and Levelt Sengers(2) have shown a linear relationship between: Equation (Available In Full Paper) in the range 175 °C and the critical point of water at 374 °C. For small, non-polar molecules and noble gases, Harvey and Levelt Sengers(2) have shown that the use of the equation: Over the last 25 years there have been a number of reports in the literature of planned or executed field tests of the electric heating process, mostly based on the ohmic dissipation of electric energy in the formation. Electrothermic Co., for example, stimulated four wells of the Little Tom field in South Texas

Henry's law constants of tetrachloroethylene, trichloroethylene, cis-dichloroethylene, and trans-dichloroethylene in air−aqueous surfactant systems were experimentally determined by the equilibrium partitioning in closed systems method. Polyoxyethylene (10) octylphenol, sodium dodecyl sulfate, and cetyltrimethylammonium bromide were used as surfactants. The effects of temperature and surfactant concentration were investigated, and the results demonstrated that the Henry's law constants increased as temperature was increased and decreased as surfactant concentration was increased. The decrease in the Henry's law constants became obvious above the critical micelle concentration. The effect of surfactant addition on the Henry's law constant was larger for the more hydrophobic species. The micelle−water partitioning coefficients (Kmw) for the chlorinated ethylene-surfactant pairs were estimated from the Henry's law constants. The values of Kmwestimated from the Henry's law constants at high surfactant concentrations had a small standard error. On the basis of the experimental data, equations to estimate Henry's law constants in air−aqueous surfactant systems as a function of temperature and surfactant concentration were constructed. All of the equations estimated the experimental data with R2 values above 0.96.

Solubilities and diffusivities of various gases (helium, nitrogen, carbon dioxide, argon, neon, krypton, and monochlorodifluoromethane) in molten or thermally softened polymers (polyethylene, polypropylene, polyisobutylene, polystyrene, and polymethylmethacrylate) have been correlated with structural characteristics, temperature, and pressure. Temperature dependence of both Henry's Law constants and diffusivities were of the Arrhenius equation form. No appreciable effect of pressure was found for either Henry's Law constants or diffusivities up to 300 atm. Earlier correlations for Henry's Law constants in solid polymer systems were found to be inapplicable for molten and thermally softened polymers. New correlations were developed individually for the latter systems. The correlating factor used was the gas Lennard‐Jones force constant. Existing correlations for diffusivities were also found not to apply to molten and thermally softened systems. New correlations were again developed on an individual polymer basis. These related diffusivity to gas Lennard‐Jones collision diameter or molecular diameter. Generalized correlations were also developed that held for a number of polymers. These were for both Henry's Law constants and diffusivities.

The modelling of gas solubility in the aqueous phase is important in CO(2) flooding. In this paper, an efficient method for modelling this effect in a compositional simulator is presented. The oil and gas phases are modelled with an equation-of-state and the aqueous phase with Henry's Law. By assuming that the water component is present only in the aqueous phase and by all appropriate choice of primary variables, a compositional simulator with a two-phase flash-calculation module can be modified to handle gas solubility in the aqueous phase without the need of a three-phase flash-calculation module. Example runs of CO(2) flooding and WAG processes show that gas-solubility effects on the recovery are significant. Introduction Because water exists abundantly in hydrocarbon reservoirs either as a fluid originally in place or as an injected fluid, it becomes important [0 model the effects or gas solubility in the aqueous phase during miscible displacements, This is particularly important for CO(2) injection because CO(2) is more soluble in water than the other light gases. Most compositional simulators assume thermodynamic equilibrium between the hydrocarbon phases (oil and gas) only and consider water as an inert fluid that does not contribute to the phase behaviour. This limits the utility of these simulators especially for CO(2)-injection studies where a significant portion of the injection CO(2): may dissolve in the aqueous phase. It was shown by Li and Nghiem(1) that the solubility of gases in the aqueous phase can be modelled successful using Henry's Law. They also provided correlations for the calculation of Henry's Law constant for reservoir gases. In this paper, an efficient method for modelling the gas solubility using Henry's Law is presented. The advantage of using Henry's Law for modelling gas solubility in water is that it eliminates the need for a tedious and time consuming three-phase (oil-gas-aqueous) equation-of-state (EOS) fIash-calculation module. This is accomplished by modelling the oil and gas phases with an EOS and the aqueous phase with Henry's Law. By assuming that the water component is present only in the aqueous phase and by an appropriate choice of primary variables, a compositional simulator with a two-phase flash-calculation can be modified to handle gas solubility in the aqueous phase without the requirement of a three-phase flash-calculation module. Formulation and Equations In all subsequent discussions, the gas and oil phases are modelled with a cubic EOS and the solubility in the aqueous phase is modelled with Henry's Law. It is further assumed that the water component exists only in the aqueous phase. Henry's Law Henry's Law gives the following expression for the fugacity or Component i in the aqueous phase: Equation (1) Available In Full Paper. where the subscript i denotes a non-water component, and w the water component. Hi is the Henry's Law constant of Component i, yia is the mole fraction of Component i in the aqueous phase and fia is the fugacity of Component i in the aqueous phase. The variation of Henry's Law constant, Hi with respect to pressure and temperature is given by

The Henry's law constant defines the solubility of a gas in a liquid solution. In this study, a new method for measuring the Henry's law constant is described. This new colorimetric method is suited for gases which react with water to form acidic or basic solutions when they dissolve, and makes use of measuring the concentration of two forms of a colorimetric pH indicator. By measuring the concentration of the protonated and deprotonated forms of the indicator with UV-visible absorption spectroscopy, the concentration of the hydronium in solution was determined. After determining the hydronium concentration, the equilibrium expression for the dissolved gas reacting with water was solved to determine the concentration of the dissolved gas. The concentration of the dissolved gas and the measured partial pressure of the dissolved gas at equilibrium were then used to calculate the Henry's law constant for the gas. The efficacy of the method is demonstrated by measuring the Henry's law constant for carbon dioxide in water over a range of pressures (0.680 - 5.10 atm). The results obtained with this method are comparable to the value for the Henry's law constant that have been previously reported via more traditional methods, and yielded values for the Henry's law constant for carbon dioxide that ranged from 3.45 × 10-2 to 3.99 × 10-2 M atm-1.

Our previous measurements of the temperature dependencies of Henry's law constants of 26 polychlorinated biphenyls (PCBs) showed a well-defined linear relationship between the enthalpy and the entropy of phase change. Within a homologue group, the Henry's law constants converged to a common value at a specific isoequilibrium temperature. We use this relationship to model the temperature dependencies of the Henry's law constants of the remaining PCB congeners. By using experimentally measured Henry's law constants at 11 degrees C for 61 PCB congeners described in this paper combined with the isoequilibrium temperatures from our previous measurements of Henry's law constants of 26 PCB congeners, we have derived an empirical relationship between the enthalpies and the entropies of phase change for these additional PCB congeners. A systematic variation in the enthalpies and entropies of phase change was found to be partially dependent on the chlorine number and substitution patterns on the biphenyl rings, allowing further estimation of the temperature dependence of Henry's law constants for the remaining 122 PCB congeners. The enthalpies of phase change for all 209 PCB congeners ranged between 10 and 169 kJ mol(-1), where the enthalpies of phase change decreased as the number of ortho chlorine substitutions on the biphenyl rings increased within homologue groups. These data are used to predict the temperature dependence of Henry's law constants for all 209 PCB congeners.

Henry’s Law describes the partitioning of molecules into liquid and gas phases at low concentrations. Henry’s Law, which is based upon a species-dependent constant and the gas phase partial pressure, is useful for predicting phase behavior of dilute solutes. However, Henry’s Law constants are difficult to measure experimentally or to predict using structure-property or thermodynamic models. Herein, molecular simulations were used to calculate Henry’s Law constants for 18 volatile organic compounds (VOCs) present in bourbon. The novel simulations analyzed solvation thermodynamics of small organic molecules in 120 proof ethanol. A fast-growth non-equilibrium free energy method was used in which the VOC of interest was removed or added, thus affecting the overall thermodynamic properties of the system. Work distributions for forward and reverse transitions were analyzed. The Gibbs free energy of solvation for each VOC was thus estimated, which is directly related to the chemical potential of the VOC, thus providing access to Henry’s law constants. Results of models were compared to values of aqueous solvation from literature. The results of the simulations were precise over multiple iterations, but a lack of experimental data with respect to solvation in ethanol-water solutions presents difficulties in assessing the accuracy of presented models.

The Henry's law and diffusion constants of vinyl chloride in poly(vinyl chloride) were determined at temperatures of 24, 90, 120, 150, and 170°C for weight fractions of vinyl chloride between 0.2 × 10−3 and 0.8 × 10−3. Above 90°C, Henry's law applies; values of the constant increase with temperature from 1.8 × 102 to 5.5 × 102 atm per unit weight fraction of dissolved vinyl chloride. The heat of desorption is about 15 kJ/mole. At 24°C, the nominal Henry's law constant was smaller than would have been obtained by extrapolating the values found at higher temperature. The diffusion constants increase with temperature from about 2 × 10−13 to 3 × 10−7 cm2/sec. The activation energy for diffusion is about 110 kJ/mole between 90 and 170°C. Although all values were determined in the absence of air, it is likely that they apply to polymer in air. They may, therefore, be used to calculate the vinyl chloride content in the gas above poly(vinyl chloride) under specific processing conditions.

The Henry's law constant of N 2O and CO 2 in aqueous binary and ternary amine solutions (MEA, DEA, DIPA, MDEA, and AMP)

High-pressure solubility of light gases in heavy n-alkanes from a predictive equation of state: Incorporating Henry's law constant into binary interaction parameter