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Chakib Bouallou - One of the best experts on this subject based on the ideXlab platform.
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Carbon dioxide absorption by ammonia intensified with membrane Contactors
Clean Technologies and Environmental Policy, 2016Co-Authors: Carol Toro Molina, Chakib BouallouAbstract:Membrane gas absorption technology is a promising alternative for CO2 removal from post-combustion coal-fired flue gases. This study examines an alternative which consists in absorbing carbon dioxide by ammonia aqueous solution in a membrane Contactor to improve the capture processes and to intensify the gas–liquid transfer. Absorption measurements through a membrane Contactor have been made. The influence of the material nature constituting the membrane and operating parameters on the capture efficiency has been studied. The potentialities of dense skin membrane Contactors are discussed with regard to both increased CO2 mass transfer performances and mitigation of ammonia volatilization. The results have shown that it is possible to capture CO2 from ammonia through a membrane with capture efficiency greater than 90 %. The membrane limits ammonia losses but does not eliminate it. The experimental results are used to calculate an intensification factor of 5, which represents the comparison between the membrane overall absorption rate to that of the column.
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Comparison of post-combustion CO2 capture by solutions of ammonia and organic amines: Assessment using direct and indirect Contactors
Energy Procedia, 2014Co-Authors: Carol Toro-molina, Chakib BouallouAbstract:Simulation results of the thermal power plant fed with pulverized coal (PC) including CO2 capture have been performed using the Aspen Plus software. The flue gases containing CO2 from post-combustion have been captured by ammonia and monoethanolamine solvents. Ammonia solvent has been used in two processes by direct Contactor (without a membrane Contactor) and by indirect Contactor (membrane). A parametric study has been conducted to clarify the optimal conditions to capture CO2 by ammonia. The comparative study suggests that the use of ammonia as a solvent in chemical absorption is the most interesting process for the PC thermal power plant. The capture process by indirect Contactor (membrane Contactor) reduces efficiency decrease to only 6.3 points.
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Experimental study of CO2 absorption in a hollow fiber membrane Contactor
2009Co-Authors: Thérèse Kallas, Elodie Chabanon, Guillaume Garmain, Chakib BouallouAbstract:A new experimental setup achieved by the CEP-Paris is presented. A hollow fiber membrane (Poly-3-OP) was used as gas-liquid Contactors for CO2 removal from CO2N2 feed gas stream. CO2 is transferred from gas phase through the hollow fiber membrane Contactor into a liquid phase under condition of high or low pressure. CO2 concentration is measured inlet and outlet the module by gas chromatograph. CO2 removal efficiency was given for chemical solvents monoethanolamine (MEA), Nmethyldiethanolamine (MDEA) and promising blend of methyldiethanolamine and triethylene tetramine (MDEA+TETA) will be tested. The results show that an increase of solvent's flow lead to an increase of CO 2 removal efficiency which is appreciably the same as well in the case of MEA as in that of MDEA+TETA when gas flow is lower than 20L/h. Effect of CO2 inlet mass percentage on removal efficiency depends on the solvents used. An important increase of CO2 removal efficiency is reached by using MDEA+TETA solutions as solvents, as well as MEA under specific operating parameters.
Eric Favre - One of the best experts on this subject based on the ideXlab platform.
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3.9 Membranes Contactors for Intensified Gas–Liquid Absorption Processes
Comprehensive Membrane Science and Engineering, 2017Co-Authors: Elodie Chabanon, Eric FavreAbstract:The absorption of a gaseous solute in a liquid is a classical unit operation with a large number of applications in numerous industrial sectors. A direct contact between the gas and liquid phase in order to promote mass transfer is classically applied for industrial equipment (trays, packings, stirred tanks, Venturi scrubbers, etc.). The concept of membrane Contactor for gas–liquid absorption (or stripping, i.e., gaseous-solute removal from a liquid), which makes use of a gas-permeable membrane interposed between the gas and liquid phase, has been recently proposed and shows several advantages: possibility to independently control the gas and liquid flow rates, no sensitivity to orientation, no foaming or entrainment problems, and larger compactness. The latter characteristic, also named intensification, is of major interest. It is potentially achievable due to the very large specific gas–liquid interfacial area provided by membrane modules, but it also requires the membrane mass-transfer resistance to be as low as possible. The different types of membrane materials (microporous hydrophobic and dense-skin composite) are detailed, and the associated properties and mechanisms, which govern mass-transfer properties, are presented. Wetting, fouling, and degradation issues are more specifically discussed, with the associated impact on membrane mass-transfer performances. The different levels of modeling that can be proposed for the simulation of a membrane-Contactor module are shown, with a gradual complexity approach. The key role of the membrane mass-transfer coefficient is highlighted. The different applications of membrane Contactors are finally presented: blood oxygenators, oxygen removal (food, microelectronics, and pharma), carbonated beverages, aromas or volatile compounds recovery, effluent treatment, bioreactors, etc. Postcombustion carbon capture and natural-gas treatment could generate important new markets for which process intensification is of key interest. The challenges and perspectives of membrane Contactors, with a particular emphasis on process intensification framework, are finally discussed.
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Adiabatic modelling of CO 2 capture by amine solvents using membrane Contactors
Journal of Membrane Science, 2015Co-Authors: David Zaidiza, Denis Roizard, Sabine Rode, Christophe Castel, Bouchra Belaissaoui, Thibaut Neveux, Camel Makhloufi, Eric FavreAbstract:The modelling of CO 2 chemical absorption using hollow fiber membrane Contactors is addressed. A one-dimensional, multicomponent adiabatic model for the CO 2 absorption using an aqueous solution of monoethanolamine is established. The model is validated using both, laboratory and pilot-scale experiments. The simulation results are compared to those from an isothermal model in order to investigate the influence of heat release on Contactor performance. When industrial relevant operating conditions are applied, the adiabatic simulations show significant axial temperatures peaks, up to 30 °C. Correspondingly, local gas-phase vapor molar fractions values of up to 0.4 are attained. If compared to simulations from an isothermal model, deviations of about 60% were obtained, thus clearly demonstrating the necessity of adiabatic modelling under industrial conditions. Intensification factors comprised of between 2 and 10, for external fiber radiuses in the range of 300–100 μm are attained. The mass transfer coefficient is varied from 10 À 4 to 10 À 3 m s À 1 which corresponds to experimentally observed values of microporous membranes that are presumably resistant to liquid breakthrough. However, wetting remains a major problem in microporous as well as composite membranes, as capillary condensation is likely to occur.
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Evaluating the intensification potential of membrane Contactors for gas absorption in a chemical solvent: A generic one-dimensional methodology and its application to CO2 absorption in monoethanolamine
Journal of Membrane Science, 2012Co-Authors: S. Rode, Denis Roizard, P.t. Nguyen, Roda Bounaceur, Christophe Castel, Eric FavreAbstract:A generic one-dimensional model was developed, leading to a better comprehension of the intensification potential of hollow fiber membrane Contactors for gas absorption in a chemical solvent. The methodology was applied to an illustrative case study, namely the chemical absorption of CO2 in industrially relevant operating conditions for post-combustion capture. These conditions introduce numerous constraints, thereby leading to an estimate of the dimensions of the hollow fiber membrane Contactor as a function of its geometrical characteristics. In the parametric range that was considered, the flow regime is laminar, and the concentration profiles are fully developed both for the gas and liquid flows that lead to mass-transfer coefficients that are independent of the flow velocities. The influence of the external fiber radius and the membrane permeability and thickness on overall process performance are clearly evident. Liquid flow around the fibers that proceeds with gas flowing through the lumen of the fibers is shown to be particularly effective. Under favorable conditions (i.e., an external fiber radius of 2 × 10−4 m and sufficient membrane permeability), the overall Contactor volume can be divided by a factor of approximately twenty relative to the volume of an absorption column. Under these conditions, the superficial gas velocity can be maintained at a high level (i.e., greater than 1 m s−1) with a drop in gas and liquid pressure of only approximately 50 mbar.
Sanjeev Jain - One of the best experts on this subject based on the ideXlab platform.
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Performance characteristics of cross-flow membrane Contactors for liquid desiccant systems
Applied Energy, 2015Co-Authors: Sanjeev JainAbstract:Membrane based indirect contact liquid desiccant dehumidification technology subsides the serious concern of liquid desiccant droplet carryover observed in conventional direct contact liquid desiccant systems. In the membrane Contactor the air and liquid desiccant streams flow in alternate channels in cross-flow arrangement, separated by micro-porous semi-permeable hydrophobic membranes. Only water vapor can pass through the membranes but liquid desiccant cannot permeate. A two-dimensional steady-state mathematical model for semipermeable membrane based indirect Contactors as dehumidifiers for liquid desiccant dehumidification applications has been developed. The model can predict the air and desiccant parameters inside the dehumidifier and the outlet parameters for a given input parameters. Five different membrane Contactors have been fabricated and series of experiments have been conducted to validate the mathematical model. Aqueous solution of lithium chloride has been used as desiccant. The maximum deviations between experimental and predicted values are within ±10% for outlet specific humidity and outlet enthalpy of air, ±15% deviation in dehumidification effectiveness and ±20% deviation in enthalpy effectiveness. The distributions of major parameters viz. temperature, humidity, concentration, etc., within the Contactor have been presented. Parametric analysis has been carried out to study the effects of membrane characteristics, Contactor design, fluid flow rates, ambient conditions and desiccant concentration on the performance of the Contactors.
Hikaru Kitamura - One of the best experts on this subject based on the ideXlab platform.
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CO2 removal by hollow-fiber gas-liquid Contactor
Energy Conversion and Management, 1995Co-Authors: Nobuyuki Nishikawa, Michio Ishibashi, Nobuo Akutsu, Hiroyo Matsumoto, Toshihiro Kamata, Hikaru KitamuraAbstract:We have conducted a series of basic experiments for CO2 removal from the flue gas of thermal power plants by use of hollow-fiber gas-liquid Contactors. It was confirmed that the stability of PTFE membrane having a high degree of hydrohobicity is more than 6,600 hours and that by improving the degree of hydrophobicity on the surface of the membrane, the durability and performance of the membrane can be improved. Furthermore, we have confirmed that flow characteristics of fluid in hollow-fiber can be estimated based on Hagen-Poiseuille law. The overall volumetric mass transfer coefficient Ka(=K×a) of the hollow-fiber gas-liquid Contactor is more than 5 times larger than that of a conventional packed bed, which suggests that adoption of the present method has the advantage of making the absorber more compact.
Denis Roizard - One of the best experts on this subject based on the ideXlab platform.
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Effects of water condensation on hollow fiber membrane Contactor performance for CO2 capture by absorption into a chemical solvent
Journal of Membrane Science, 2018Co-Authors: Kévin Villeneuve, Alicia Andrea Torres Hernandez, David Albarracin Zaidiza, Denis Roizard, Sabine RodeAbstract:The present study investigates the impact of water vapor condensation on the performance of hollow fiber membrane Contactors for CO2 capture by absorption into a chemical solvent. A one-dimensional adiabatic transfer model for CO2 absorption in Monoethanolamine (MEA) has been implemented in a commercial simulation environment and condensation experiments have been performed in a laboratory scale membrane Contactor module. The results from these experiments show that water vapor condensation occurs in the gas phase or at the gas-membrane surface inside the fiber lumen, but not in the membrane pores. This condensation had no effect on the carbon capture efficiency, but did lead to an increase of the gas-side pressure drop and to liquid water at the gas outlet. Using simulations permitted us to better understand why condensation occurs in the fiber lumen. Indeed, it is the combined conditions of rapid heat-transfer within the membrane and relatively slow mass transfer that lead to vapor oversaturation in the gas phase promoting condensation. In industrial conditions for membrane Contactor applications where water condensation is most likely to occur, membrane wetting due to condensation may thus not happen, which is an encouraging result for the membrane technology
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Adiabatic modelling of CO 2 capture by amine solvents using membrane Contactors
Journal of Membrane Science, 2015Co-Authors: David Zaidiza, Denis Roizard, Sabine Rode, Christophe Castel, Bouchra Belaissaoui, Thibaut Neveux, Camel Makhloufi, Eric FavreAbstract:The modelling of CO 2 chemical absorption using hollow fiber membrane Contactors is addressed. A one-dimensional, multicomponent adiabatic model for the CO 2 absorption using an aqueous solution of monoethanolamine is established. The model is validated using both, laboratory and pilot-scale experiments. The simulation results are compared to those from an isothermal model in order to investigate the influence of heat release on Contactor performance. When industrial relevant operating conditions are applied, the adiabatic simulations show significant axial temperatures peaks, up to 30 °C. Correspondingly, local gas-phase vapor molar fractions values of up to 0.4 are attained. If compared to simulations from an isothermal model, deviations of about 60% were obtained, thus clearly demonstrating the necessity of adiabatic modelling under industrial conditions. Intensification factors comprised of between 2 and 10, for external fiber radiuses in the range of 300–100 μm are attained. The mass transfer coefficient is varied from 10 À 4 to 10 À 3 m s À 1 which corresponds to experimentally observed values of microporous membranes that are presumably resistant to liquid breakthrough. However, wetting remains a major problem in microporous as well as composite membranes, as capillary condensation is likely to occur.
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Evaluating the intensification potential of membrane Contactors for gas absorption in a chemical solvent: A generic one-dimensional methodology and its application to CO2 absorption in monoethanolamine
Journal of Membrane Science, 2012Co-Authors: S. Rode, Denis Roizard, P.t. Nguyen, Roda Bounaceur, Christophe Castel, Eric FavreAbstract:A generic one-dimensional model was developed, leading to a better comprehension of the intensification potential of hollow fiber membrane Contactors for gas absorption in a chemical solvent. The methodology was applied to an illustrative case study, namely the chemical absorption of CO2 in industrially relevant operating conditions for post-combustion capture. These conditions introduce numerous constraints, thereby leading to an estimate of the dimensions of the hollow fiber membrane Contactor as a function of its geometrical characteristics. In the parametric range that was considered, the flow regime is laminar, and the concentration profiles are fully developed both for the gas and liquid flows that lead to mass-transfer coefficients that are independent of the flow velocities. The influence of the external fiber radius and the membrane permeability and thickness on overall process performance are clearly evident. Liquid flow around the fibers that proceeds with gas flowing through the lumen of the fibers is shown to be particularly effective. Under favorable conditions (i.e., an external fiber radius of 2 × 10−4 m and sufficient membrane permeability), the overall Contactor volume can be divided by a factor of approximately twenty relative to the volume of an absorption column. Under these conditions, the superficial gas velocity can be maintained at a high level (i.e., greater than 1 m s−1) with a drop in gas and liquid pressure of only approximately 50 mbar.