The following is a list of the publications of John Carroll. Copies of these papers can be obtained by contacting John Carroll via E-mail or by regular mail at:
FlowPhase Inc.
#330, 2749 - 39 Avenue NE
Calgary, Alberta, CANADA T1Y 4T8Many of these papers are directly related to the development and application of AQUAlibrium. A significant fraction of the papers are applicable to the gas processing industry. In addition, several of these papers are on the solubility of natural gas components (particularly hydrogen sulfide and carbon dioxide) in aqueous solutions of alkanolamines. Others report measurements and correlations of vapor-liquid equilibria in systems of importance to the natural gas industry.
A report on the water content of sour natural gas and acid gases is now available. This report summarizes virtually all of the available experimental data for these systems and demonstrates the accuracy of AQUAlibrium to predict them. For information about obtaining a copy of this report, please contact us. Copies of this report we provided free of charge to registered users of AQUAlibrium.
We are pleased that the work by John Slupsky, Alan Mather, and myself on the solubility of carbon dioxide in water is quoted in recent editions of the CRC Handbook of Chemistry and Physics (ed. David R. Lide). The CRC Handbook is a standard reference book consulted by many scientists and engineers working in a wide range of disciplines. The system carbon dioxide + water has been studied often and we believe that the inclusion of our work in the CRC Handbook is demonstrative of our thorough treatment of the subject.
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Abstract - The solubility of methane in 3 kmol/m³ solutions of monoethanolamine, diethanolamine, and triethanolamine was measured from 25° to 125°C and pressures up to about 13 MPa. Measurements were also made for the solubility of methane in water at 25° to 125°C and pressures up to 18 MPa in order to confirm the accuracy of the experimental technique. It is demonstrated that methane is more soluble (in terms of mole fraction) in the amine solution than in pure water. Furthermore, the solubility is an increasing function of the size of the alkanolamine. The solubility data are modeled using a Henry's law approach and the results are summarized in terms of salting-in coefficients.
Abstract - In this study experimental data are presented for the solubility of methane in 3.0 and 6.0 kmol/m³ (30.5 and 59.5 wt%) solutions of 2-(2-aminoethoxy)ethanol (which is also called diglycolamine®). Temperatures in this study ranged from 25° to 125°C and pressures to 13 MPa. The data were incorporated into a rigorous thermodynamic model that has been applied to other similar systems. The new data were then compared with the data available in the literature.
In pure water and low amine concentrations it is demonstrated that the isobaric solubility exhibits a minimum. However, for high amine concentration there is a somewhat surprising result - the isobaric solubility is an increasing function of the temperature over the range of temperature studied here.
Abstract - Data are presented for the solubility of methane and of ethane in a 3 kmol/m³ (34.7 mass %) solution of methyldiethanolamine. Temperatures in this study ranged from 25° to 130°C and pressure to 13 MPa. The data were incorporated into a rigorous thermodynamic model that has been applied to other similar systems. The model is a combined Henry's law-Raoult's law approach. The solubilities in the alkanolamine solution are correlated in terms of the salting-in ratio, the ratio of the mole fraction solubility in the amine solution to that in pure water.
Abstract - Although the phase equilibria in the system n-butane + water have been studied frequently, a review of the experimental results has revealed serious disagreement among the various investigators. In this work, the data from the literature are supplemented with some new solubility data. These data are then used with a model based on Henry's law to construct a model for the phase equilibria.
Abstract - The isoenergetic-isochoric (specified internal energy - specified volume, UV) flash is required in order to simulate the dynamic filling of a process vessel. Unlike other types of flashes, such as the isenthalpic-isobaric or isothermal-constant phase fraction flash calculations, for example, none of the intensive variables (temperature and pressure) is known in the UV flash. This fact introduces a higher degree of difficulty in solving the particular flash calculation than that of the other types. In this paper, we will share our experience in solving the UV flash problem.
Abstract - A model is presented for correlating the solubility of methane, ethane, and propane in pure water and aqueous solutions of alkanolamines. The model, which can be applied to both liquid and gaseous hydrocarbons, uses a form of Henry's law for the aqueous phase and an equation of state for the non-aqueous phases. It is demonstrated that only a relatively simple modification of the pure water model is required to extend the model for the solubility of hydrocarbons in alkanolamine solutions.Note - This model is used in our subsequent work for the solubility in other hydrocarbon + amine + water systems studied in the laboratory.
Abstract - Aqueous solutions of alkanolamines are often used to remove the acid gas components (CO2 and H2S) from hydrocarbon streams. The application of the absorption process to liquid hydrocarbons is not as well developed as its use for gaseous hydrocarbons streams. As well, experimental data for systems of amine solutions and liquefied petroleum gases are scarce. New data are presented for the equilibria in the system n-butane-water-methyldiethanolamine (MDEA). A knowledge of the phase behavior in this system is needed to model the equilibria encountered in the quaternary and quinary systems of industrial importance. In this work vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibria have been measured at temperatures between 25°C and 150°C at pressures up to 20 MPa for a 3 M solution of MDEA.
Abstract - The model of Deshmukh and Mather (1981) is a popular method for correlating and predicting vapor-liquid equilibria in systems containing acid gases (hydrogen sulfide and carbon dioxide) and aqueous solutions of alkanolamines. The model includes phase equilibrium between an aqueous liquid and a gas as well as chemical equilibrium in the aqueous phase. A recent review by Weiland et al. (1993) demonstrated the accuracy of the correlation. Presented here is a model based on that of Deshmukh and Mather (1981) for calculating the distribution of acid gases between two liquid phases - an aqueous phase and a non-aqueous liquid (typically propane- or butane-rich liquid).
In the new model the phase equilibrium is modeled using a modified Henry's law approach. Fugacities of the components in the non-aqueous phase are calculated using the Peng-Robinson (1976) equation of state. All parameters in the model are taken from the literature. Thus the model represents a prediction of the behavior. It is demonstrated that the prediction are in good agreement with the available experimental data.
This paper is a follow up to an earlier paper.
Abstract - There is a large discrepancy in the values reported in the literature for the azeotrope in the system propane-hydrogen sulfide. Previous investigations did not measure the azeotrope directly, but inferred it from other equilibrium measurements. In this work the azeotrope was measured directly. Correlations based on the new data were developed. In addition the binary critical locus was determined. The new values for the critical locus are in good agreement with the values reported in the literature. A comparison was made with several simple correlations for binary critical loci. The results of these comparisons showed that while good correlations exist for the critical temperature, the correlations for the critical pressure are not as good.
Abstract - Measurements of the phase equilibria in the carbon dioxide - propane - 3 M MDEA system have been made at 35° and 40°C at pressures up to 15.5 MPa. Vapor-liquid, liquid-liquid and vapor-liquid-liquid equilibria were determined. The vapor-liquid equilibrium data were compared with the model of Deshmukh and Mather.
Abstract - A review of the literature reveal a paucity of data for the vapor-liquid equilibrium of systems containing hydrogen sulfide and paraffin hydrocarbons. In order to estimate the vapor-liquid equilibrium of systems for which no data exist, a correlation of the interaction parameter for the Peng-Robinson equation of state is provided.
Abstract - Henry's law is often used to correlate the solubility of a gas in water. Such an approach is frequently employed to calculate the solubility of hydrogen sulphide in water. However, Wright and Maass clearly demonstrated that the strict Henry's law did not apply to the solubility of hydrogen sulphide in water. That is, the solubility of hydrogen sulphide is not proportional to its partial pressure, even at seemingly low pressure. By accounting for the non-idealities in the vapour phase, Carroll and Mather showed how a simple modification of Henry's law could be used for moderate pressure (up to 1 MPa). In this paper, a further extension of Henry's law is used to model the vapor-liquid equilibrium at higher pressures and temperatures. It is also applied to liquid-liquid and vapor-liquid-liquid equilibria, areas where Henry's law is rarely used.
Abstract - In this work, new data are presented for the equilibrium in the system hydrogen sulfide-propane-water-methyldiethanolamine (MDEA). The concentration of the MDEA in the aqueous phase was 3 M. Data for the equilibrium between an aqueous liquid, a non-aqueous liquid and a vapor were obtained for five temperatures between 0° and 100°C and for pressures up to 8.8 MPa.
Abstract - The solubility of hydrogen sulfide and carbon dioxide in an aqueous solution containing 35 wt% methyldiethanolamine (MDEA) has been measured at 40° and 100°C at partial pressure of the acid gas up to 530 kPa. Some data for hydrogen sulfide in a 50 wt% solution of MDEA were also obtained. Also, densities of CO2-aqueous MDEA solutions were measured at 40°C.
Abstract - The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol/m³) aqueous solution of N-methyldiethanolamine at 40° and 100°C have been measured. Partial pressures of the acid gases ranged from 0.006 to 101 kPa at 40°C and 4 to 530 kPa at 100°C.
Abstract - Henry's law is an important part of the modern science of physical chemistry. However, it is used in all branches of science where the solubility of a gas in a liquid is an important phenomenon. Notwithstanding, many people are surprised by the age of Henry's law. This paper places Henry's law in a historical context. Henry's law is as old as the science of modern chemistry.
Abstract - The solubility of nitrous oxide in water was measured for temperatures in the range 10° to 140°C at pressures to 20 MPa. A few points for the solubility of liquid N2O in water at 25°C were obtained. The solubility data were correlated using a Henry's law-type model.
Abstract - A review of the literature for the system propane-hydrogen sulfide revealed significant discrepancies between the various experimental investigations. This is particularly true for the location of the azeotrope. This paper investigates the problems with the experimental data for this system. Each investigation is reviewed in detail to determine sources of error. The Peng-Robinson equation of state is used as a tool for this interpretation. What is revealed is a clearer picture of the phase equilibrium that is consistent with the data of the major investigations of this system.
Abstract - The system carbon dioxide-water has been studied often. However, there is some controversy about the thermodynamic description of the behavior of this system. Some researchers indicate that the system CO2-H2O is accurately modeled by the Krichevsky-Kasarnovsky equation. Others say that it is not. This paper investigates this controversy. As a part of this study an overview of Henry's law and a discussion of the limitations of the Krichevsky-Kasarnovsky equation are presented. From the analysis presented in this paper, it must be concluded that for temperatures lower than about 100°C, the system CO2-H2O is accurately modeled by the Krichevsky-Kasarnovsky equation. On the other hand, at 100°C and higher it is not. In order to arrive at this conclusion, four models of the solubility were investigated. Using these models, it is clearly demonstrated that the activity coefficients are not negligible and hence the Krichevsky-Kasarnovsky equation is not applicable at higher temperatures.
Abstract - Aqueous solutions of alkanolamines are commonly used to strip acid gases (CO2 and H2S) from hydrocarbon streams. Process for stripping acid gases from gaseous streams are well understood; however, the application to liquids is not as advanced. Experimental data available are scarce for systems containing aqueous amine solutions and the constituents of liquefied petroleum gases. To this end, new data are presented for the equilibria in the system propane-water- methyldiethanolamine (MDEA). A knowledge of the phase behavior in this system is required to model the equilibria encountered in the more complex systems of industrial importance.
This work is a comprehensive study of the phase equilibria in the system propane - 3 M MDEA, including vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibria. Experimental measurements were made for temperatures between 0° and 150°C at pressures up to 20 MPa. The data were correlated using the Stryjek-Vera modification of the Peng-Robinson equation of state. In addition, a composition-dependent mixing rule was required to fit the data adequately.
Abstract - The vapor pressure of aqueous N-methyldiethanolamine (MDEA) solutions were measured using a modified ebulliometer. The concentration of MDEA ranged from 10 wt% to 70 wt% and temperatures from about 55°C to 108°C. The measured vapor pressures were compared with those predicted by Raoult's law. The maximum deviation between the predicted values and experiment is only 5.3 kPa.
Abstract - The system carbon dioxide-water is of great scientific and technological importance. Thus, it has been studied often. The literature for the solubility of carbon dioxide in water is vast and interdisciplinary. An exhaustive survey was conducted and approximately 100 experimental investigations were found that reported equilibrium data at pressures below 1 MPa. A model based on Henry's law was used to correlate the low pressure data (those data up to 1 MPa).Note - This work is quoted in recent editions of CRC Handbook of Chemistry and Physics (ed. David R. Lide).
Abstract - In this paper the effects of three impurities (methanol, methanethiol, and nitrogen) on the liquid-liquid-vapour (LLV) locus of hydrogen sulphide-water are estimated using an equation of state. The location of the LLV locus limits the pressure at which the Girdler-Sulphide process can operate; the highest pressure being the point where a second, non-aqueous liquid (L2) forms. Thus it is important to be able to estimate the effect that various impurities will have on the pressure where a second liquid will form. A seemingly small amount of methanethiol is predicted to have a dramatic effect on the L2-dew point. From this analysis, the addition of 1 mol% of thiol reduces the L2-dew point of an equimolar water-hydrogen sulphide mixture by as much as 1 MPa. Methanol also lowers the L2-dew point, but the effect is less dramatic than with the thiol. Finally, the presence of nitrogen is predicted to increase the L2-dew point. One reason for the different effect of the various components is the phase in which they are present in the largest concentration. methanol tends to concentrate in the aqueous phase, CH3SH in the non-aqueous liquid, and nitrogen in the vapour.
Abstract - Recently revealed problems with the fluid phase equilibria data for the system H2S-H2O as presented by Selleck et al. (1952) prompted this review of the hydrate-forming conditions. The smoothed tables of Selleck et al. (1952) along the three-phase loci are replaced with equations which are based on a critical review of all of the experimental data.Note - A pressure-temperature diagram, similar to that in this paper, except to scale, is given on the Hydrates Page.
Abstract - In the light of the information presented by Carroll and Mather (1989), a new interpretation is presented for the often-quoted, smoothed data of Selleck, Carmichael, and Sage (1952) for the phase equilibrium in the system water-hydrogen sulphide. The data of Carroll and Mather show that the liquid-liquid-vapour locus extends to higher temperatures than believed by Selleck et al. Experimental data from several sources are correlated using the Stryjek-Vera (1986) modification of the Peng-Robinson (1976) equation of state. It is demonstrated that the fit of the raw data via the equation of state is as good as the smoothing of Selleck et al.
Abstract - There exist some controversy about the solubility of hydrogen sulphide in water - notably the effect of pressure on the solubility. This paper reviews the experimental data for this system for temperatures between 0° and 90°C and for pressures up to 1 MPa. A simple model is used to correlate all of the data, including data that had previously been rejected as inaccurate. It is demonstrated that observed deviations from the strict Henry's law can be explained by the non-ideality of the vapour phase. Also non-idealities in the liquid phase are negligible for the stated range of temperature and pressure.
Abstract - Experimental data are presented for the liquid-liquid-vapor (LLV) equilibrium for the system water-hydrogen sulphide. Conditions ranged from the hydrate-liquid-liquid-vapour quadruple point (29.4°C and 2.23 MPa) to beyond the critical temperature of hydrogen sulphide (100.3°C). The maximum temperature at which three phases can exist is 106.2°C at 9.39 MPa. This is 6°C higher than previously believed.
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A study on predicting acid-gas densities for the pressure and temperature ranges relevant to acid-gas injection schemes found that only one common equation of state gave unsatisfactory results.
While rigorous equations of state are reliable tools for getting physical properties, real-time plant needs often demand a simpler approach. This paper offers practical guidance for using simple equations and models to estimate properties over a narrowly defined range of pressure, temperature, and composition.
To many process engineers, the Joule-Thomson effect implies the cooling of a gas upon expansion. However, there are cases where a fluid actually warms upon expansion. Those cases are the subject of this paper.
Previous articles on Herny's Law generated several additional questions, which are answered here.
For acid-gas injection systems, pressure composition diagrams indicate the significant phase changes that H2S and water mixtures can undergo when going from an amine unit to downhole in an injection well. Note - A version of this paper is available on-line.
Examination of phase equilibria in a binary hydrogen sulfide and water system explains some nuances of acid-gas injection.Note - A pressure-temperature diagram, similar to that in this paper, except to scale, is given on the Hydrates Page.
Acid gas injection requires an understanding of the complexities of gas phase behavior and physical properties.
Note - Copies of the computer program listed in this paper can be obtained by contacting John Carroll.
It enables data from relatively simple studies to be applied to more-complex industrial situations.
It certainly is one of the most often used principles of physical chemistry, but it is also one of the most misused.
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Note - A version of this paper is available on-line.
Note - A version of this paper is available on-line.
Note - A version of this paper is available on-line.
Note - A version of this paper is available on-line.
Note - A version of this paper is available on-line.
Note - Supplemental material promised at the time of the conference is available on-line.
Note - A version of this paper is available on-line.
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This page, and all its contents, are Copyright © 1998 by John J. Carroll, Alberta, CANADA.