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Gabrielsen J, Svendsen HF, Michelsen ML, Stenby EH, Kontogeorgis GM. Experimental validation of a rate-based model for CO2 capture using an AMP solution. Chem Eng Sci 2007. [DOI: 10.1016/j.ces.2007.01.034] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Berg RW, Brunsgaard Hansen S, Shapiro AA, Stenby EH. Diffusion measurements in binary liquid mixtures by Raman spectroscopy. APPLIED SPECTROSCOPY 2007; 61:367-73. [PMID: 17456254 DOI: 10.1366/000370207780466316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
It is shown that Raman spectroscopy allows determination of the molar fractions in mixtures subjected to molecular diffusion. Spectra of three binary systems, benzene/n-hexane, benzene/cyclohexane, and benzene/acetone, were obtained during vertical (exchange) diffusion at several different heights (z) as a function of time. A procedure to determine time-dependent concentration profiles and diffusion coefficients is described in detail for one system, and results are given for the two other cases. For the system benzene/cyclohexane, much lower diffusion coefficients than reported in the literature were found, even in a thermostatically controlled diffusion cell, recording spectra through circulating water. For the system benzene/acetone, the determined diffusion coefficients were in good agreement with the literature data. The limitations of the Raman method are discussed, and it is concluded that many more systems ought to be studied. It is pointed out that diffusion profiles can be obtained in ternary and higher systems, where proper measurements are almost nonexistent.
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Kontogeorgis GM, Michelsen ML, Folas GK, Derawi S, von Solms N, Stenby EH. Ten Years with the CPA (Cubic-Plus-Association) Equation of State. Part 1. Pure Compounds and Self-Associating Systems. Ind Eng Chem Res 2006. [DOI: 10.1021/ie051305v] [Citation(s) in RCA: 310] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kontogeorgis GM, Michelsen ML, Folas GK, Derawi S, von Solms N, Stenby EH. Ten Years with the CPA (Cubic-Plus-Association) Equation of State. Part 2. Cross-Associating and Multicomponent Systems. Ind Eng Chem Res 2006. [DOI: 10.1021/ie051306n] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Folas GK, Kontogeorgis GM, Michelsen ML, Stenby EH. Application of the Cubic-Plus-Association Equation of State to Mixtures with Polar Chemicals and High Pressures. Ind Eng Chem Res 2006. [DOI: 10.1021/ie0509241] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gabrielsen J, Michelsen ML, Stenby EH, Kontogeorgis GM. Modeling of CO2 absorber using an AMP solution. AIChE J 2006. [DOI: 10.1002/aic.10963] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Folas GK, Kontogeorgis GM, Michelsen ML, Stenby EH. Application of the Cubic-Plus-Association (CPA) Equation of State to Complex Mixtures with Aromatic Hydrocarbons. Ind Eng Chem Res 2005. [DOI: 10.1021/ie050976q] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Broholm MM, Christophersen M, Maier U, Stenby EH, Höhener P, Kjeldsen P. Compositional evolution of the emplaced fuel source in the vadose zone field experiment at Airbase Verløse, Denmark. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:8251-63. [PMID: 16294861 DOI: 10.1021/es048557s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A field experiment was performed in a sandy vadose zone, studying the fate of an emplaced fuel-NAPL source, composed of 13 hydrocarbons and a tracer. The UNIFAC model was used to testthe nonideal behavior of the source, and the numerical model MIN3P was used for assessing the effect of biodegradation on source evolution. The diffusive loss to the surrounding vadose zone and the atmosphere created temporary gradients in mole fractions of the individual compounds within the source NAPL. The evolution of the source composition corresponded in general with expectations based on Raoult's Law, with the exception thatthe mole fractions of aromatic compounds in the source NAPL decreased faster than fractions of aliphatic compounds of similar volatility. Calculation of activity coefficients (y) using the UNIFAC model implied nonideal conditions, with composition-dependent gammas different from 1. Positive deviations were calculated for the aromatic compounds. The effect of biodegradation on source depletion, evaluated by numerical modeling, was greater for the aromatic as compared to the aliphatic compounds. Hence, the faster depletion of the aromatic relative to aliphatic compounds of similar volatility is both a result of the nonideality of the mixture and a result of partitioning and biodegradation in the pore-water. Vapor concentrations of the compounds in the source were in reasonable agreement with predictions based on the modified Raoult's Law with the UNIFAC predicted gammas and the NAPL composition for the most volatile compounds. For the less volatile compounds, the measured vapor concentrations were lower than predicted with the largest deviations for the least volatile compounds. This field experiment illustrated that nonideal behavior and bioenhanced source depletion need to be considered at multicomponent NAPL spill sites.
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Cheng H, Kontogeorgis GM, Stenby EH. Correlation and Prediction of Environmental Properties of Alcohol Ethoxylate Surfactants Using the UNIFAC Method. Ind Eng Chem Res 2005. [DOI: 10.1021/ie050096b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Folas GK, Gabrielsen J, Michelsen ML, Stenby EH, Kontogeorgis GM. Application of the Cubic-Plus-Association (CPA) Equation of State to Cross-Associating Systems. Ind Eng Chem Res 2005. [DOI: 10.1021/ie048832j] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gabrielsen J, Michelsen ML, Stenby EH, Kontogeorgis GM. A Model for Estimating CO2 Solubility in Aqueous Alkanolamines. Ind Eng Chem Res 2005. [DOI: 10.1021/ie048857i] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Solms NV, Zecchin N, Rubin A, Andersen SI, Stenby EH. Direct measurement of gas solubility and diffusivity in poly(vinylidene fluoride) with a high-pressure microbalance. Eur Polym J 2005. [DOI: 10.1016/j.eurpolymj.2004.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Saghir MZ, Jiang CG, Derawi SO, Stenby EH, Kawaji M. Theoretical and experimental comparison of the Soret coefficient for water-methanol and water-ethanol binary mixtures. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2004; 15:241-247. [PMID: 15592763 DOI: 10.1140/epje/i2004-10063-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Accepted: 10/21/2004] [Indexed: 05/24/2023]
Abstract
In multicomponent mixtures, a much richer variety of phenomena can occur than in simple (single-component) fluids. Natural convection in single-component fluids is due to buoyancy forces caused by temperature gradients. In multicomponent mixtures, buoyancy forces may also be caused by concentration gradients. Because natural convection, molecular diffusion, and thermal conduction have different relaxation time scales, a wide variety of resulting convective motions and heat and mass distributions might occur. In some fluid mixtures such as water-ethanol system, for instance, ethanol diffuses much more slowly than heat, and because of this difference in time scales oscillatory convection might occur. In a multicomponent mixture, the total molar flux consists of two parts: the convective molar flux and the diffusive molar flux (resulting from the difference between the component velocity and the bulk velocity). The diffusion molar flux of a component depends, not only on its own mole fraction gradient (Fickian diffusion), but also on the gradient of all the components present in the mixture (cross-molecular diffusion). The diffusion flux depends also on the pressure gradient (pressure diffusion; the so-called gravitational effect) and temperature gradient (thermal diffusion; the so-called Soret effect). Firoozabadi's thermal diffusion model was applied to calculate the Soret coefficient, as well as the thermal diffusion coefficient and molecular diffusion coefficient for methanol-water and ethanol-water mixtures at 310.65 K temperature and 1 bar pressure with 10% water mass fraction. The results were compared with experimental data (J.K. Platten, in Proceedings of the 5th International Meeting on Thermodiffusion (IMT5), Lyngby, Aug. 2002, Philos. Mag. 83, Nos. 17-18 (2003)), as well as theoretical predictions with other models. A better agreement with the experimental data using the Firoozabadi model was achieved.
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Heidemann RA, Madsen J, Stenby EH, Andersen SI. Wax precipitation modeled with many mixed solid phases. AIChE J 2004. [DOI: 10.1002/aic.10292] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Derawi SO, Kontogeorgis GM, Michelsen ML, Stenby EH. Extension of the Cubic-Plus-Association Equation of State to Glycol−Water Cross-Associating Systems. Ind Eng Chem Res 2003. [DOI: 10.1021/ie0206103] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cheng H, Kontogeorgis GM, Stenby EH. Prediction of Micelle Formation for Aqueous Polyoxyethylene Alcohol Solutions with the UNIFAC Model. Ind Eng Chem Res 2001. [DOI: 10.1021/ie010072e] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zéberg-Mikkelsen CK, Quiñones-Cisneros SE, Stenby EH. Viscosity Modeling of Light Gases at Supercritical Conditions Using the Friction Theory. Ind Eng Chem Res 2001. [DOI: 10.1021/ie000987d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zéberg-Mikkelsen CK, Quiñones-Cisneros SE, Stenby EH. Viscosity Prediction of Hydrogen + Natural Gas Mixtures (Hythane). Ind Eng Chem Res 2001. [DOI: 10.1021/ie0010464] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Derawi SO, Kontogeorgis GM, Stenby EH. Application of Group Contribution Models to the Calculation of the Octanol−Water Partition Coefficient. Ind Eng Chem Res 2000. [DOI: 10.1021/ie000361n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dandekar AY, Stenby EH. Measurement of Phase Boundaries of Hydrocarbon Mixtures Using Fiber Optical Detection Techniques. Ind Eng Chem Res 2000. [DOI: 10.1021/ie990834u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lindeloff N, Andersen SI, Stenby EH, Heidemann RA. Phase-Boundary Calculations in Systems Involving More than Two Phases, with Application to Hydrocarbon Mixtures. Ind Eng Chem Res 1999. [DOI: 10.1021/ie980415h] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Shapiro AA, Stenby EH. Analysis of Multicomponent Adsorption Close to a Dew Point. J Colloid Interface Sci 1998; 206:546-557. [PMID: 9756667 DOI: 10.1006/jcis.1998.5683] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We develop the potential theory of multicomponent adsorption close to a dew point. The approach is based on an asymptotic adsorption equation (AAE) which is valid in a vicinity of the dew point. By this equation the thickness of the liquid film is expressed through thermodynamic characteristics of the bulk phase. The AAE makes it possible to study adsorption in the regions of both the normal and the retrograde condensation. A simple correlation of the Kelvin radius for capillary condensation and the thickness of the adsorbed film is established. Numerical testing shows good agreement between the AAE and the direct calculations, even if the mixture is not close to a dew point. Copyright 1998 Academic Press.
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