Accurate modeling of supercritical CO2 for sustainable processes: Water + CO2 and CO2 + fatty acid esters mixtures

Abstract Supercritical fluid technology has allowed significant improvements in several industrial processes, and there are still many opportunities for further applications in new emergent areas. This contribution provides some perspectives on drivers and opportunities for new or advanced applications of supercritical fluids, including the search for sustainable processes and healthy products. It also addresses some of the needs, such as using refined modeling tools with a specific treatment taking into account the long range fluctuations in the density (or composition for the case of mixtures) as one approaches the critical point to accurately design the process in this region. New results are presented on the application of the crossover soft-SAFT equation of state to two motivating systems involving supercritical CO2, the CO2–water mixture and the solubility of supercritical CO2 in fatty acid esters. Both systems are challenging from a modeling perspective as they are highly non-ideal. Crossover soft-SAFT gives very accurate results, compared to available experimental systems, for the CO2–water mixtures. The equation is also able to predict the critical line in quantitative agreement with experimental data with one constant binary parameter, being a step forward in modeling the behavior of this mixture. The equation also gives excellent results when modeling the solubility of supercritical CO2 in fatty acid esters, with two binary parameters, independent of the temperature and composition, in this case.

[1]  Liming W. Salvino,et al.  Calculation of density fluctuation contributions to thermodynamic properties of simple fluids , 1992 .

[2]  S. Enders,et al.  Phase equilibrium and interfacial properties of water + methane mixtures , 2012 .

[3]  K. Wilson.  Renormalization Group and Critical Phenomena. I. Renormalization Group and the Kadanoff Scaling Picture , 1971 .

[4]  A. Galindo,et al.  Modelling the phase equilibria and excess properties of the water + carbon dioxide binary mixture , 2007 .

[5]  Lourdes F. Vega,et al.  Prediction of Binary and Ternary Diagrams Using the Statistical Associating Fluid Theory (SAFT) Equation of State , 1998 .

[6]  K. Gubbins,et al.  Thermodynamics of polyatomic fluid mixtures—II , 1978 .

[7]  J. Gross,et al.  Modeling the phase equilibria of hydrogen sulfide and carbon dioxide in mixture with hydrocarbons and water using the PCP-SAFT equation of state , 2010 .

[8]  P. H. van Konynenburg,et al.  Critical lines and phase equilibria in binary van der Waals mixtures , 1980, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[9]  F. Llovell,et al.  Capturing the solubility minima of n-alkanes in water by soft-SAFT. , 2009, The journal of physical chemistry. B.

[10]  George Jackson,et al.  SAFT: Equation-of-state solution model for associating fluids , 1989 .

[11]  Michael E. Fisher,et al.  Renormalization of Critical Exponents by Hidden Variables , 1968 .

[12]  F. Llovell,et al.  Phase equilibria, surface tensions and heat capacities of hydrofluorocarbons and their mixtures including the critical region , 2010 .

[13]  K. Arai,et al.  Vapour—liquid equilibria for binary mixtures of carbon dioxide and fatty acid methyl esters , 1989 .

[14]  Xiaoyan Ji,et al.  SAFT1-RPM Approximation Extended to Phase Equilibria and Densities of CO2−H2O and CO2−H2O−NaCl Systems , 2005 .

[15]  S. Al-Athel,et al.  Report of the World Commission on Environment and Development: "Our Common Future" , 1987 .

[16]  Michael E. Fisher,et al.  Critical Exponents in 3.99 Dimensions , 1972 .

[17]  U. Maeder.  H 2 O-CO 2 mixtures; a review of P-V-T-X data and an assessment from a phase-equilibrium point of view , 1991 .

[18]  Gerd Brunner,et al.  The 20th anniversary of the Journal of Supercritical Fluids-A special issue on future directions in supercritical fluid science and technology , 2009 .

[19]  A. Galindo,et al.  Phase equilibria, excess properties, and henry's constants of the water + carbon dioxide binary mixture , 2007 .

[20]  V. Gerbaud,et al.  Modeling the vapor–liquid equilibrium and association of nitrogen dioxide/dinitrogen tetroxide and its mixtures with carbon dioxide , 2008 .

[21]  Walter G Chapman,et al.  Application of Dipolar Chain Theory to the Phase Behavior of Polar Fluids and Mixtures , 2001 .

[22]  K. Gubbins,et al.  Thermodynamics of polyatomic fluid mixtures—I theory , 1978 .

[23]  E. A. Brignole,et al.  Modeling and optimization of supercritical fluid processes , 2009 .

[24]  J. Gallagher,et al.  The Thermodynamic Behavior of the CO2‐H2O System from 400 to 1000 K, up to 100 Mpa and 30% Mole Fraction of CO2 , 1993 .

[25]  M. M. Piñeiro,et al.  Interfacial properties of water/CO2: a comprehensive description through a Gradient Theory-SAFT-VR Mie approach. , 2010, The journal of physical chemistry. B.

[26]  João A. P. Coutinho,et al.  Densities and Viscosities of Fatty Acid Methyl and Ethyl Esters , 2010 .

[27]  Fèlix Llovell,et al.  Global fluid phase equilibria and critical phenomena of selected mixtures using the crossover soft-SAFT equation. , 2006, The journal of physical chemistry. B.

[28]  Sheng Zhang,et al.  Renormalization group theory for fluids , 1993 .

[29]  R. Privat,et al.  Development of a Predictive Equation of State for CO2 + Ethyl Ester Mixtures Based on Critical Points Measurements , 2014 .

[30]  M. J. Cocero,et al.  Encapsulation and co-precipitation processes with supercritical fluids: Fundamentals and applications , 2009 .

[31]  Rui Sun,et al.  Prediction of vapor-liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part I: Application to H2O-CO2 system , 2010 .

[32]  M. Wertheim,et al.  Fluids with highly directional attractive forces. IV. Equilibrium polymerization , 1986 .

[33]  L. Ramos,et al.  High-pressure phase equilibrium measurements and thermodynamic modeling for the systems involving CO2, ethyl esters (oleate, stearate, palmitate) and acetone , 2014 .

[34]  A. A. Refaat,et al.  Different techniques for the production of biodiesel from waste vegetable oil , 2010 .

[35]  F. Gironi,et al.  Separation of fish oils ethyl esters by means of supercritical carbon dioxide: Thermodynamic analysis and process modelling , 2006 .

[36]  João A. P. Coutinho,et al.  Evaluation of the CO2 Behavior in Binary Mixtures with Alkanes, Alcohols, Acids and Esters Using the Cubic-Plus-Association Equation of State , 2011 .

[37]  J. A. White,et al.  Contribution of fluctuations to thermal properties of fluids with attractive forces of limited range: theory compared with PϱT and Cv data for argon , 1992 .

[38]  M. Wertheim,et al.  Fluids with highly directional attractive forces. II. Thermodynamic perturbation theory and integral equations , 1984 .

[39]  J. Coutinho,et al.  Development of simple and transferable molecular models for biodiesel production with the soft-SAFT equation of state , 2014 .

[40]  Lourdes F. Vega,et al.  THERMODYNAMIC BEHAVIOUR OF HOMONUCLEAR AND HETERONUCLEAR LENNARD-JONES CHAINS WITH ASSOCIATION SITES FROM SIMULATION AND THEORY , 1997 .

[41]  L. Diamond,et al.  Solubility of CO2 in water from −1.5 to 100 °C and from 0.1 to 100 MPa: evaluation of literature data and thermodynamic modelling , 2003 .

[42]  R. Lugo,et al.  Modeling Liquid–Liquid and Liquid–Vapor Equilibria of Binary Systems Containing Water with an Alkane, an Aromatic Hydrocarbon, an Alcohol or a Gas (Methane, Ethane, CO2 or H2S), Using Group Contribution Polar Perturbed-Chain Statistical Associating Fluid Theory , 2011 .

[43]  John A. Zollweg,et al.  The Lennard-Jones equation of state revisited , 1993 .

[44]  Josep C. Pàmies,et al.  SAFT Modeling of the Solubility of Gases in Perfluoroalkanes , 2004 .

[45]  Dominique Richon,et al.  Vapour-liquid equilibria in the carbon dioxide-water system, measurement and modelling from 278.2 to 318.2K , 2004 .

[46]  Danielle Barth,et al.  Phase Equilibria Measurements and Modeling of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide , 2001 .

[47]  L. Vega,et al.  Critical behavior and partial miscibility phenomena in binary mixtures of hydrocarbons by the statistical associating fluid theory , 1998 .

[48]  K. Gubbins,et al.  Equation of State for Lennard-Jones Chains , 1994 .

[49]  Josep C. Pàmies,et al.  Vapor-Liquid Equilibrium of Carbon Dioxide-Perfluoroalkane Mixtures: Experimental Data and SAFT Modeling , 2006 .

[50]  A. Islam,et al.  Application of SAFT equation for CO2 + H2O phase equilibrium calculations over a wide temperature and pressure range , 2012 .

[51]  M. Wertheim,et al.  Fluids with highly directional attractive forces. I. Statistical thermodynamics , 1984 .

[52]  F. Varaminian,et al.  Modeling the solubility of light reservoir components, HCFCs and HFCs in water using the CPA and sPC-SAFT equations of state , 2013 .

[53]  J. Trusler,et al.  Measurement and modeling of the phase behavior of the (carbon dioxide + water) mixture at temperatures from 298.15 K to 448.15 K , 2013 .

[54]  George Jackson,et al.  New reference equation of state for associating liquids , 1990 .

[55]  Jianwen Jiang,et al.  Equation of state for thermodynamic properties of chain fluids near-to and far-from the vapor–liquid critical region , 1999 .

[56]  Fèlix Llovell,et al.  Thermodynamic properties of Lennard-Jones chain molecules: renormalization-group corrections to a modified statistical associating fluid theory. , 2004, The Journal of chemical physics.

[57]  Yigui Li,et al.  Prediction of phase equilibria for CO2–C2H5OH–H2O system using the SAFT equation of state , 2000 .

[58]  J. Rasaiah,et al.  Thermodynamic perturbation theory for simple polar fluids. II , 1972 .

[59]  Ioannis G. Economou,et al.  Modeling the phase equilibria of a H2O–CO2 mixture with PC-SAFT and tPC-PSAFT equations of state , 2012 .

[60]  A. E. Mather,et al.  The Solubility of Carbon Dioxide in Water at Low Pressure , 1991 .

[61]  M. Wertheim,et al.  Fluids with highly directional attractive forces. III. Multiple attraction sites , 1986 .

[62]  K. Johnston,et al.  Colloids in supercritical fluids over the last 20 years and future directions , 2009 .

[63]  E. Ibáñez,et al.  Deacidification of olive oil by countercurrent supercritical carbon dioxide extraction: Experimental and thermodynamic modeling , 2009 .

[64]  Lourdes F. Vega,et al.  Vapor−Liquid Equilibria and Critical Behavior of Heavy n-Alkanes Using Transferable Parameters from the Soft-SAFT Equation of State , 2001 .