Dr. L. Antonio Estévez |
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University of Puerto Rico, Mayaguez College of Engineering Chemical Engineering ProfessorAppointed: 1995 Mississippi State University (On sabbatical leave from UPRM) Dave C. Swalm School of Chemical Engineering Visiting ProfessorAppointed: 2007 |  |
Mailing AddressMississippi State University Dave C. Swalm School of Chemical Engineering Mississippi State, Mississippi 39762-9595United States | Contact InformationPhone: (662) 325-0211 Fax: (662) 325-2482 Mobile: (787) 604-8819 lae71@msstate.edu http://inqu.uprm.edu/faculty/estevez.html |
Expertise and Research Interests
- Natural-Convection Heat Transfer in Supercritical Fluids
The main objective of this study is to estimate the heat-transfer coefficients for natural convection from a heated, vertical flat plate into a supercritical fluid. In the first part of this study, an equation for the coefficient of thermal expansion or thermal expansivity for a van der Waals gas was derived. The van der Waals expansivity and the expansivity from accurate, tabulated PVT data were calculated for carbon dioxide, butane, and water. The trends of both expansivities were similar and both diverged at the critical point. These features confirm the validity of the equation obtained in this work.
In the second part of this study, the van der Waals expansivity was used in the momentum equation, which, along with the energy and continuity equations, forms a set of coupled equations. This set of equations was solved numerically by finite differences. A FORTRAN code was written to obtain the velocity and temperature profiles along the plate. The local Nusselt number was then calculated and plotted as a function of the local Rayleigh number for five pre-selected supercritical conditions and one low-pressure condition far from the critical point. A curve corresponding to the Churchill and Chu's empirical correlation was added as a reference to all plots. It was observed in these plots that the curve obtained at conditions far from the critical point approaches the empirical-correlation curve. But most importantly, the curves at supercritical conditions are significantly above the empirical-correlation curve, indicating that the natural convection heat-transfer phenomenon is considerably enhanced in the critical region.
- Molecular Simulation of the Sorption and Swelling Phenomena for Polymer-Supercritical Fluid Systems
Contact between polymers and supercritical fluids occurs in several new technologies such as polymer impregnation. There is ample experimental evidence that polymers swell upon absorbing a supercritical fluid (SCF). Attempts to use fundamental or basic principles to describe these phenomena have not been fully satisfactory. Molecular simulation is becoming an increasingly popular tool in various fields such as in phase-equilibrium calculations. In this project, Monte Carlo simulations is being used to describe the sorption and swelling processes that occur when a polymer is brought into contact with a supercritical fluid, e.g., supercritical carbon dioxide. In a first stage, a bead-spring model has been used in the simulations to study the thermodynamics of simple polymer systems. Properties such as mean radius of gyration, mean end-to-end distance, and phase transitions have been studied using a parallel tempering Monte Carlo algorithm. In a second stage, the Monte Carlo Gibbs ensemble method will be used to model the sorption of supercritical fluids in polymers.
- Solubility of Pharmacologcial Drugs in Supercritical Fluids
Supercritical fluids (SCFs) have attracted variable attention during the last 30 years. Recent developments in SCF technology have shown that it is capable of solving challenging specialty separations. An interesting application of particular interest in Puerto Rico is related to the pharmaceutical industry. A possible application could be visualized as the substitution of a series of conventional processes by a simpler stage involving supercritical fluids. To this end, an extensive database of basic properties has to be developed. These properties include phase equilibria or solubility data as well as transport properties (i.e.,viscosities, and diffusivities). The supercritical-fluids group at University of Puerto Rico has engaged in a number of challenging projects in this area. These include the measurement of solubility of a number of drugs in supercritical carbon dioxide, the development of various models based on equations of states to describe these solubilities, and the measurement of diffusion coefficients of liquid species in supercritical carbon dioxide.
- Measuring and Modeling the Axial Dispersion Coefficient in a Bubble Column with a Non-Newtonian Liquid Phase
The experimental characterization and modeling of the mixing in bubble columns when the liquid phase has a non-Newtonian rheological behavior undoubtedly needs more attention given the broad range of industrial applications of bubble columns, e.g., as bioreactors and for hydrotreatment of petroleum fractions. The non-Newtonian nature of the liquid phase is usually caused by the presence of live microorganisms and/or micro- or nanoparticles. Despite the relevance of the subject, studies emphasizing the non-Newtonian behavior of the liquid phase have been investigated only sparsely through the years. Therefore, the objective of the this research is to perform a holistic study of the mixing phenomenon in the liquid phase of bubble columns with a non-Newtonian liquid phase. In this approach, all aspects are to be taken into account: rheology, careful experimentation, and rigorous mathematical analysis.
The experimental part will include: (a) the measurement of the rheological properties of the solutions or suspensions to be used (e.g., carboxymethylcellulose solutions or micro or nanosuspensions); and (b) experimentation to characterize the mixing of the liquid phase and to measure the gas-phase holdup. This approach will allow relating the hydrodynamic behavior of the liquid phase to its rheological properties.
- Hydrodynamic Studies of Slurry Bubble Columns for Water Treatment Applications
There is no question that water quality is of utmost importance to society and that good quality water is becoming a precious commodity. These facts have prompted creativeness in developing ways to recycle and reuse water, and therefore existing water treatment techniques must be in continuous improvement and new, more effective techniques have to be developed. Many of the emerging and classical techniques involve the contact of water with a gas phase (e.g., aeration) or with a gas and solid phases. On the other hand, bubble columns are devices extensively used in chemical industry and their potential has not been fully exploited in the water-treatment field. Many of the techniques involve three-phase contact, and slurry bubble columns are particularly suitable for that type of application. Therefore, the use of slurry bubble columns for water treatment is being explored. This will be done in two stages: first, the hydrodynamics of slurry bubble columns will be studied, and then actual treatment techniques using slurry bubble columns will be proposed. Three-phase processes are probably more relevant to high-BOD waters, such as industrial wastewaters coming from industries such as pharmaceutical, food, or the like. Therefore, places or regions such as Puerto Rico, with a high concentration of this type of industries, will be particularly benefited.
- Stripping VOCs from Water Bubble Columns
The presence of volatile organic components (VOC's) in water is a problem that has been considered since more than three decades. There are many technologies that offer different approaches to solve this problem. Some of these technologies are packed-tower aeration, granular activated carbon, and powered activated carbon. An experimental setup has been used to carry out experiments on the removal of THM from water. The apparatus consists of a 2.5-m-high, 20-cm-diameter, Plexiglas bubble column where steady-state concentration profiles were measured. A mathematical model with no adjustable parameters was developed. The experimental results and the model prediction coincided very nicely.
- Model of Efficiences of Distillation Sieve Trays
Despite the development of new separations processes, distillation remains as the most important one based on the use and impact on the economy of the chemical process industry. Design and simulation of distillation columns require accurate algorithms to compute the number of theoretical stages and accurate methods to predict the Murphree tray efficiency in terms of the operating conditions. While plate-to-plate computational methods are well developed, estimation models for tray efficiencies available today are not necessarily accurate enough. Fair (1987) states that this has long been a nebulous area for the design of distillation columns, and it would appear that improved models for contacting efficiency can represent major advances in the state of distillation design technology. The main difficulty in the prediction of distillation tray efficiencies results from the complexity of the gas-liquid contact in the tray, and from the high number of variables and effects affecting the efficiency. One of the most difficult effects to account for is the liquid phase velocity pattern. This has been subjected to numerous studies since Kirschbaum (1934) first pointed out that liquid flow maldistribution could cause a reduction on tray efficiency.
The main objective of this study is to estimate the heat-transfer coefficients for natural convection from a heated, vertical flat plate into a supercritical fluid. In the first part of this study, an equation for the coefficient of thermal expansion or thermal expansivity for a van der Waals gas was derived. The van der Waals expansivity and the expansivity from accurate, tabulated PVT data were calculated for carbon dioxide, butane, and water. The trends of both expansivities were similar and both diverged at the critical point. These features confirm the validity of the equation obtained in this work.
In the second part of this study, the van der Waals expansivity was used in the momentum equation, which, along with the energy and continuity equations, forms a set of coupled equations. This set of equations was solved numerically by finite differences. A FORTRAN code was written to obtain the velocity and temperature profiles along the plate. The local Nusselt number was then calculated and plotted as a function of the local Rayleigh number for five pre-selected supercritical conditions and one low-pressure condition far from the critical point. A curve corresponding to the Churchill and Chu's empirical correlation was added as a reference to all plots. It was observed in these plots that the curve obtained at conditions far from the critical point approaches the empirical-correlation curve. But most importantly, the curves at supercritical conditions are significantly above the empirical-correlation curve, indicating that the natural convection heat-transfer phenomenon is considerably enhanced in the critical region.
- Molecular Simulation of the Sorption and Swelling Phenomena for Polymer-Supercritical Fluid Systems
Contact between polymers and supercritical fluids occurs in several new technologies such as polymer impregnation. There is ample experimental evidence that polymers swell upon absorbing a supercritical fluid (SCF). Attempts to use fundamental or basic principles to describe these phenomena have not been fully satisfactory. Molecular simulation is becoming an increasingly popular tool in various fields such as in phase-equilibrium calculations. In this project, Monte Carlo simulations is being used to describe the sorption and swelling processes that occur when a polymer is brought into contact with a supercritical fluid, e.g., supercritical carbon dioxide. In a first stage, a bead-spring model has been used in the simulations to study the thermodynamics of simple polymer systems. Properties such as mean radius of gyration, mean end-to-end distance, and phase transitions have been studied using a parallel tempering Monte Carlo algorithm. In a second stage, the Monte Carlo Gibbs ensemble method will be used to model the sorption of supercritical fluids in polymers.
- Solubility of Pharmacologcial Drugs in Supercritical Fluids
Supercritical fluids (SCFs) have attracted variable attention during the last 30 years. Recent developments in SCF technology have shown that it is capable of solving challenging specialty separations. An interesting application of particular interest in Puerto Rico is related to the pharmaceutical industry. A possible application could be visualized as the substitution of a series of conventional processes by a simpler stage involving supercritical fluids. To this end, an extensive database of basic properties has to be developed. These properties include phase equilibria or solubility data as well as transport properties (i.e.,viscosities, and diffusivities). The supercritical-fluids group at University of Puerto Rico has engaged in a number of challenging projects in this area. These include the measurement of solubility of a number of drugs in supercritical carbon dioxide, the development of various models based on equations of states to describe these solubilities, and the measurement of diffusion coefficients of liquid species in supercritical carbon dioxide.
- Measuring and Modeling the Axial Dispersion Coefficient in a Bubble Column with a Non-Newtonian Liquid Phase
The experimental characterization and modeling of the mixing in bubble columns when the liquid phase has a non-Newtonian rheological behavior undoubtedly needs more attention given the broad range of industrial applications of bubble columns, e.g., as bioreactors and for hydrotreatment of petroleum fractions. The non-Newtonian nature of the liquid phase is usually caused by the presence of live microorganisms and/or micro- or nanoparticles. Despite the relevance of the subject, studies emphasizing the non-Newtonian behavior of the liquid phase have been investigated only sparsely through the years. Therefore, the objective of the this research is to perform a holistic study of the mixing phenomenon in the liquid phase of bubble columns with a non-Newtonian liquid phase. In this approach, all aspects are to be taken into account: rheology, careful experimentation, and rigorous mathematical analysis.
The experimental part will include: (a) the measurement of the rheological properties of the solutions or suspensions to be used (e.g., carboxymethylcellulose solutions or micro or nanosuspensions); and (b) experimentation to characterize the mixing of the liquid phase and to measure the gas-phase holdup. This approach will allow relating the hydrodynamic behavior of the liquid phase to its rheological properties.
- Hydrodynamic Studies of Slurry Bubble Columns for Water Treatment Applications
There is no question that water quality is of utmost importance to society and that good quality water is becoming a precious commodity. These facts have prompted creativeness in developing ways to recycle and reuse water, and therefore existing water treatment techniques must be in continuous improvement and new, more effective techniques have to be developed. Many of the emerging and classical techniques involve the contact of water with a gas phase (e.g., aeration) or with a gas and solid phases. On the other hand, bubble columns are devices extensively used in chemical industry and their potential has not been fully exploited in the water-treatment field. Many of the techniques involve three-phase contact, and slurry bubble columns are particularly suitable for that type of application. Therefore, the use of slurry bubble columns for water treatment is being explored. This will be done in two stages: first, the hydrodynamics of slurry bubble columns will be studied, and then actual treatment techniques using slurry bubble columns will be proposed. Three-phase processes are probably more relevant to high-BOD waters, such as industrial wastewaters coming from industries such as pharmaceutical, food, or the like. Therefore, places or regions such as Puerto Rico, with a high concentration of this type of industries, will be particularly benefited.
- Stripping VOCs from Water Bubble Columns
The presence of volatile organic components (VOC's) in water is a problem that has been considered since more than three decades. There are many technologies that offer different approaches to solve this problem. Some of these technologies are packed-tower aeration, granular activated carbon, and powered activated carbon. An experimental setup has been used to carry out experiments on the removal of THM from water. The apparatus consists of a 2.5-m-high, 20-cm-diameter, Plexiglas bubble column where steady-state concentration profiles were measured. A mathematical model with no adjustable parameters was developed. The experimental results and the model prediction coincided very nicely.
- Model of Efficiences of Distillation Sieve Trays
Despite the development of new separations processes, distillation remains as the most important one based on the use and impact on the economy of the chemical process industry. Design and simulation of distillation columns require accurate algorithms to compute the number of theoretical stages and accurate methods to predict the Murphree tray efficiency in terms of the operating conditions. While plate-to-plate computational methods are well developed, estimation models for tray efficiencies available today are not necessarily accurate enough. Fair (1987) states that this has long been a nebulous area for the design of distillation columns, and it would appear that improved models for contacting efficiency can represent major advances in the state of distillation design technology. The main difficulty in the prediction of distillation tray efficiencies results from the complexity of the gas-liquid contact in the tray, and from the high number of variables and effects affecting the efficiency. One of the most difficult effects to account for is the liquid phase velocity pattern. This has been subjected to numerous studies since Kirschbaum (1934) first pointed out that liquid flow maldistribution could cause a reduction on tray efficiency.
Funding Received
- National Science Foundation (NSF): The Central New York to Puerto Rico-Mayaguez (CNY-PR) Alliance for Graduate Education, $350,000, 2004 to 2007.
- NSF through the ERC at University of Arizona: A New Partnership between the ERC and the University of Puerto Rico Addressing Issues of Interest to both the Semiconductor and Pharmaceutical Industries, $120,000, 2004 to 2006.
- National Science Foundation (NSF): Northeast Alliance for Graduate Education and the Professoriate - NEAGEP, $249,974, 2004 to 2009.
- MRSEC-NSF-University of Massachusetts: Molecular Simulation of the Sorption and Swelling Phenomena for Polymer-Supercritical Fluid Systems, $124,814, 1999 to 2004.
- R&D Center, UPR, Mayagüez Campus: Measurement of Axial-Dispersion Coefficients in a Bubble Column with a Non-Newtonian Liquid Phase, $2,800, 1998 to 1999.
- National Science Foundation (NSF): Solid Solubilities in Supercritical Fluids for Pharmacological Applications, $112,657, 1997 to 2000.
- College of Engineering, Cornell University, Ithaca, NY: Separation of Gases using Zeolites: Simulation and Experiments, $1,765, 1997 to 1997.
- The Procter and Gamble Fund, Cincinnati, OH: Manufacturing Engineering Option for Chemical Engineering, $150,000, 1996 to 1998.
- National Science Foundation (NSF): ARI: Renovation of Research Facilities at the College of Engineering, University of Puerto Rico, Mayagüez, $225,150, 1996 to 1997.
- INDUNIV, San Juan, PR: A Combined Strategy for the Reduction of THM Concentrations in Drinking Waters of Puerto Rico, $60,000, 1989 to 1991.
- National Science Foundation (NSF): Selectivities in the Dissolution of High-Molecular-Weight Solids in Supercritical Fluids, $152,054, 1989 to 1993.
Honors and Awards
2007, 2007 Distinguished Alumnus,
University of Santiago, Chile
2000, Víctor Márquez Award,
Interamerican Confederation of Chemical Engineering
Keywords
COS Keywords:
Chemical Engineering, Heat Transfer, Petroleum Chemistry, Pharmaceuticals, Process Simulation and Control, Thermodynamics, Thermodynamics Engineering, Transport Phenomena.Additional Terms:
Bubble-Column Reactor Performance, Chemical Engineering, Distillation, Environmental Control, Freeze Drying, Lyophillization, Multiphase Reactors, Pharmaceutical Engineering, Process Simulation, Reverse Osmosis, Separation Processes, Supercritical Fluids.Qualifications
Ph.D., University of California, Davis, Chemical Engineering, 1983.
M.Sc., Universidad Central de Venezuela, Petrochemical Processes, 1977.
B.S., Universidad de Santiago de Chile, Chemical Engineering, 1975.
Publications
- Estévez, L. A. (2008) An Equation for the Mean Driving Force in Reverse Osmosis, In Preparation
- María G. Gómez, L. Antonio Estévez (2008) Rheometry and Rheology of Aqueous Solutions of Carboxymethylcellulose, In Preparation
- Lesette Monroig-Adames, David Suleiman, L. Antonio Estévez (2008) Adjusting Solute Critical Properties and Sublimation Pressure in the Correlation of Solubilities of Solids in Supercritical Fluids, In Preparation
- Alexander Ogando, L. Antonio Estévez (2008) Measurement of Diffusion Coefficients of Bromobenzenes in Supercritical Carbon Dioxide, In Preparation
- Margarita García, L. Antonio Estévez (2008) Modeling the Phase Equilibrium of Multicomponent Systems Involving Solids, Supercritical Fluids, and Cosolvents, In Preparation
- Darrel L. Sparks, L. Antonio Estévez, Rafael Hernandez, Keith Barlow, Todd French (2008) Solubility of Nonanoic (Pelargonic) Acid in Supercritical Carbon Dioxide, Journal of Chemical Engineering Data, 53 (2), 407-410
- Eduardo Vyhmeister, Anthony J. Muscat, David Suleiman, L. Antonio Estévez (2008) High-Pressure Phase Equlibria for Chlorosilane + Carbon Dioxide Mixtures, Fluid Phase Equilibria, Submitted
- María G. Gómez, L. Antonio Estévez (2008) Experimental Study of the Liquid-Phase Mixing in a Bubble Column with a Non-Newtonian Liquid, In Preparation
- María G. Gómez, L. Antonio Estévez (2008) Measurement of Gas Holdup and Two-Phase Friction Factor in a Bubble Column with a Non-Newtonian Liquid Phase, In Preparation
- Eduardo Vyhmeister, Lischen Choate, David Suleiman, L. Antonio Estévez, Anthony J. Muscat (2008) Study of low-k film repair and pore sealing using chlorosilanes dissolved in supercritical carbon dioxide, In Preparation
- María G. Gómez, L. Antonio Estévez (In preparation) Models for Stripping VOCs from Water in Bubble-Column Aerators, Canadian Journal of Chemical Engineering
- Rolando Carreńo, L. Antonio Estévez (2008) Thermal Expansivities in Supercritical Fluids From Equations of State, In Preparation
- Nazario D. Ramírez-Beltrán, Harry Rodríguez, L. Antonio Estévez (2008) Drug Stability, Pharmaceutical Manufacturing Handbook: Regulations and Quality, New York, NY, John Wiley & Sons, Inc., 581-637 pages, In Press (bookchapter)
- Darrell L. Sparks, Rafael Hernandez, L. Antonio Estévez (2007) Evaluation of Density-Based Models for the Solubility of Solids in Supercritical Carbon Dioxide and Formulation of a New Model, Chemical Engineering Science, Submitted
- Nazario D. Ramírez-Beltrán, Harry Rodríguez Vallés, L. Antonio Estévez (2007) Use of Neural Networks to Estimate Activity Coefficients, Computación Aplicada a la Industria de Processos, CAIP 2007, La Serena, Chile, Centro de Información Tecnológica, In Press
- Darrell L. Sparks, Rafael Hernandez, L. Antonio Estévez, Nicholas Meyer, Todd French (2007) Solubility of Azelaic Acid in Supercritical Carbon Dioxide, Journal of Chemical Engineering Data, 52 (4), 1246
- L. Antonio Estévez, Zalleris O. Escobar (2007) A New Mixing Rule to Model the Solubility of Solids in Supercritical Fluids, AIChE Spring Meeting, American Institute of Chemical Engineers, New York, NY, American Institute of Chemical Engineers
- L. Antonio Estévez, Harry Rodríguez-Vallés, Nazario D. Ramirez-Beltran (2007) Estimation of Activity Coefficients in Binary Systems Using Neural Networks, AIChE Spring Meeting, American Institute of Chemical Engineers, New York, NY, American Institute of Chemical Engineers
- Darrell L. Sparks, L. Antonio Estévez, Nicholas Meyer, Rafael Hernandez (2007) Solubility of Azelaic Acid in Supercritical Carbon Dioxide, I Iberoamerican Conference on Supercritical Fluids, PROSCIBA 2007
- Nazario D. Ramírez-Beltrán, Harry Rodríguez Vallés, L. Antonio Estévez (2006) A Neural Network Approach to Estimate Activity Coefficients in Binary Systems, XXII Interamerican Congress of Chemical Engineering, Interamerican Confederation of Chemical Engineering
- L. Antonio Estévez, María G. Gómez (2006) Liquid Mixing and Hydrodynamic Parameters in Bubble Columns with a Non-Newtonian Liquid Phase, XXII Interamerican Congress of Chemical Engineering, Interamerican Confederation of Chemical Engineering
- María G. Gómez, L. Antonio Estévez (2005) Mathematical Models to Describe the Stripping of Volatile Components from Water by Aeration in Bubble Columns, 7th World Congress of Chemical Engineering, European Federation of Chemical Engineering, London, England, UK, Institution of Chemical Engineers
- D. Suleiman, L. A. Estévez, J. C. Pulido, J. E. García, C. Mojica (2005) The Solubility of Anti-Inflammatory, Anti-Cancer, and Anti-HIV Drugs in Supercritical Carbon Dioxide, J. Chem. Eng. Data, 50 (4), 1234-1241
- María G. Gómez, L. Antonio Estévez (2005) Models for Stripping Volatile Solutes from Water in Bubble-Column Aerators, Latin American Congress of Heat and Mass Transfer, LATCyM 2005, Caracas, Venezuela, Universidad Simón Bolívar
- J. R. Maury-Evertsz, L. A. Estévez, G. E. López (01 Nov 2004) Effect of branching and confinement on star-branched polymeric systems, Journal of Chemical Physics, 121 (17), 8652-8657
- J. R. Maury-Evertsz, L. A. Estévez, G. E. López (8 Nov 2003) Equilibrium properties of confined single-chain homopolymers, Journal of Chemical Physics, 119 (18), 9925-9932
- E. Jara-Morante, D. Suleiman, L. A. Estévez (2003) Solubilities of Imipramine HCl in Supercritical Carbon Dioxide, Industrial & Engineering Chemistry Research, 42 (8), 1821-1823
- C. González, K. Bentil, F. D. Boudinot, A. Carlozzi, L. A. Estévez, R. Y. Johnson, J. A. Koropchak, L. B. Martin, C. Mitchell-Kernan, L. Olion, S. Ortega, G. Smith, F. Talamantes, V. Vidoli, D. W. Stewart, C. B. Lynch, Vol. 3 - Ensuring Success, Inclusiveness Series, Washington, DC, Council of Graduate Schools, Vol. 3, 2003
- C. González, K. Bentil, F. D. Boudinot, A. Carlozzi, L. A. Estévez, R. Y. Johnson, J. A. Koropchak, L. B. Martin, C. Mitchell-Kernan, L. Olion, S. Ortega, G. Smith, F. Talamantes, V. Vidoli, D. W. Stewart, C. B. Lynch, Inclusiveness Series, Vol. 2 - Recruiting for Success, Washington, DC, Council of Graduate Schools, Vol. 2, 2003
- C. González, K. Bentil, F. D. Boudinot, A. Carlozzi, L. A. Estévez, R. Y. Johnson, J. A. Koropchak, L. B. Martin, C. Mitchell-Kernan, L. Olion, S. Ortega, G. Smith, F. Talamantes, V. Vidoli, D. W. Stewart, C. B. Lynch, Inclusiveness Series, Vol. 1 - Achieving An Inclusive Graduate Community, Washington, DC, Council of Graduate Schools, Vol. 1, 2003
- L. A. Estévez, E. Jara-Morante, D. Suleiman (8 Apr 2000) Solubilities of Imipramine HCl in Supercritical Carbon Dioxide, Proceedings of the Fifth International Symposium on Supercritical Fluids, Atlanta, GA
- C. L. McCallum, L. A. Estévez (Winter 1999) Introducing Process-Design Elements in the Unit Operations Lab, Chemical Engineering Education, 33 (1), 66-70
- C. M. Mojica, J. E. García, L. A. Estévez, D. Suleiman (16 Nov 1997) An Apparatus to Measure the Solubility of Pharmaceutical Drugs in Supercritical Fluids, Preprints of Topical Conference on Separation Science and Technologies (©AIChE), W. S. W. Ho and R. G. Luo, Editors; 1997 AIChE Annual Meeting, American Institute of Chemical Engineers, pp. 508-513 pages
- C. M. Rinaldi, L. A. Estevez, D. Nicholson, M. Maddox, K. E. Gubbins (1996) Monte Carlo Simulations of Adsorption of Nitrogen/Methane Mixtures in Zeolites, Preprints of the Fifth World Congress of Chemical Engineering, American Institute of Chemical Engineers, pp. 885-890 pages
- Á. C. Caballero, L. A. Estévez (1992) Comments on "A Comparative Study of Mixing Rules in the Prediction of Solid-Vapor Equilibria", Industrial and Engineering Chemistry Research, 31 (9), 2256
- Á. C. Caballero, L. N. Hernández, L. A. Estévez (December 1992) Interaction Parameters for Binary Solid-SCF Equilibria using several EOS and Mixing Rules, Journal of Supercritical Fluids, 5 (4), 283-295
- L. Z. Pino, R. B. Solari, S. Siquier, L. A. Estévez, M. M. Yépez, A. E. Sáez (1992) Effect of Operating Conditions on Gas Holdup in Slurry Bubble Columns with a Foaming Liquid, Chemical Engineering Communications, 117, 367-382
- C. Velázquez, L. A. Estévez (February 1992) Stripping of Trihalomethanes from Drinking Water in a Bubble- Column Aerator, AIChE Journal, 38 (2), 211-218
- Á. C. Caballero, L. A. Estévez (1991) Comments on "A Comparative Study of Mixing Rules in the Prediction of Solid-Vapor Equilibria", Industrial and Engineering Chemistry Research, 30 (3), 601-605
- L. A. Estévez, L. Z. Pino, I. Cavicchioli, A. E. Sáez (1991) Effect of Surfactant Concentration on Gas Holdup in a Bubble Column with an Organic Liquid, Chemical Engineering Communications, 105, 231-239
- E. A. Müller, L. A. Estévez (December 1990) Mixing Expansivities and Grashof Numbers in Supercritical Fluids using Cubic Equations-of-State, Journal of Supercritical Fluids, 3 (3), 136-142
- E. A. Müller, C. Olivera-Fuentes, L. A. Estévez (1989) General Expressions for Multicomponent Fugacity Coefficients and Residual Properties from Cubic Equations of State, Latin American Applied Research, 19, 99-109
- E. A. Müller, A. Cavero, L. A. Estévez (1988) Improving Flow Patterns in a Distillation Tray by Modifying Downcomer Apron Shape, Chemical Engineering Communications, 74, 195-208
- O. Rivas, G. A. Bresolin, L. A. Estévez, X. Santamaría, I. Cavicchioli (1987) Effect of Gas Distribution on the Fluid Dynamics of Three-Phase Bubble Columns, Revista Técnica INTEVEP, 7 (2), 97-102
- L. A. Estévez, J. M. Smith (1985) Pseudosteady State Approximation for Fluid-Solid Reaction and for Extraction in Cylindrical Geometry, AIChE Journal, 31 (7), 1220-1222
- R. Ludwig, L. A. Estévez, J. M. Smith (1985) The Differential Reactor Approximation under Dynamic Conditions, Chemical Engineering Science, 40 (5), 759-767
Previous Positions
2006-2006, Summer Visiting Professor,
Mississippi State University,
Engineering,
Dave C. Swalm School of Chemical Engineering
2001-2003, Associate Dean,
University of Puerto Rico, Mayaguez,
Academic Affairs and Director of Graduate Studies
2000-2000, Summer Visiting Professor,
Cornell University,
Engineering,
Chemical Engineering
1999-1999, Summer Visiting Professor,
Cornell University,
Engineering,
Chemical Engineering
1998-1998, Summer Visiting Professor,
Cornell University,
Engineering,
Chemical Engineering
1996-1997, Visiting Professor,
Cornell University,
Engineering,
Chemical Engineering
1995-1995, Summer Visiting Professor,
Cornell University,
Engineering,
Chemical Engineering
1991-1995, Associate Director,
University of Puerto Rico, San Juan,
Chemical Engineering
1990-1995, Associate Professor,
University of Puerto Rico, San Juan,
Chemical Engineering
1990-1990, Associate Professor (Part-Time),
University of Puerto Rico, San Juan,
Medical Sciences Campus,
School of Pharmacy
1987-1990, Visiting Professor,
University of Puerto Rico, San Juan,
Chemical Engineering
1984-1987, Associate Professor,
Simón Bolívar University,
Caracas, Venezuela,
Thermodynamics and Transport Phenomena
1976-1984, Assistant Professor,
Simón Bolívar University,
Caracas, Venezuela,
Thermodynamics and Transport Phenomena
1975-1975, Part-time Instructor,
University of Chile,
Chemical Technology
1973-1975, Instructor,
University of Santiago,
Chemical Engineering
Languages
(Reading, Writing, Speaking)
English: (Fluent, Fluent, Fluent)
Spanish: (Fluent, Fluent, Fluent)
French: (Fluent, Basic, Functional)
Portuguese: (Functional, Basic, Functional)
Memberships
American Institute of Chemical Engineers
Interamerican Confederation of Chemical Engineering
Puerto Rico Local Section of the AIChE
Profile Details
Last Updated: 3/5/2008
COS Expertise ID #410312
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