Durable ? Soutenable ? Sur le long terme ? Le développement durable est aujourd hui un enjeu qui ... more Durable ? Soutenable ? Sur le long terme ? Le développement durable est aujourd hui un enjeu qui préoccupe la société, mais aussi les scientifiques, et cela depuis de nombreuses années. Il concerne toutes les disciplines qui, chacune et ensemble, apportent les éléments pour observer, comprendre, modéliser et mieux anticiper l'avenir que réserve le changement global. C est donc avec enthousiasme que j ai soutenu ce projet, qui est l expression de l une des missions de l organisme de recherche, qu est le CNRS.
Numerous publications on the transport of pollutants in a fixed bed, in particular in the treatme... more Numerous publications on the transport of pollutants in a fixed bed, in particular in the treatment of waters still use two-parameter models: a capacity parameter measuring the delay of the breakthrough curve (CP) and a transfer kinetics parameter to translate the dispersion observed (Thomas model and Yoon-Nelson model), The authors totally neglect the role of the hydrodynamic dispersion which however largely contributes to the spread of the curves and thus the adjustments made on the analyzed breakthrough curves are invalid, Using three examples involving fixed beds of homogeneous adsorbent beads or sand, one of Lin et al [2013] with biochar-alginate grains (diameter 2.0 mm), the following from Jang et al. [2018] with resin beads (diameter 0.8 mm), and the last of our own work with a clay-limestone quartz sand of mean diameter 0.4 mm (Benaouag et al., 2018) we analyzed the validity of these models, For this we used as reference model a model with 4 parameters (Mixers in Cascade wit...
Modeling the non-equilibrium transport of linearly interacting solutes in porous media The transp... more Modeling the non-equilibrium transport of linearly interacting solutes in porous media The transport of linearly interacting solutes in porous media is investigated with the help of residence time distributions, transfert functions, methods of system dynamics, and time-moment analyses. The classical one-dimensional convection-dispersion equation is extended to two-region (mobile-immobile water) transport by including diffusional mass transfert limitations characteristic of aggregated porous media. The two region model is further revised by incorporating the effects of multiple retention sites (in parallel or in series), multiple porosity levels, and arbitrary but steady flow fields. It is shown that different physical situations can be represented by a relatively small number of transfert functions containing only two types of parameters : distribution coefficients to account for equilibrium properties, and characteristic times reflecting kinetic processes. Relevant kinetic processe...
Process engineering for environment protection The concepts and methodologies of the process engi... more Process engineering for environment protection The concepts and methodologies of the process engineering are useful and carry out for environment protection and sustainable development. Instead of an exhaustive presentation of the purification and treatment systems, this paper illustrates this approach by examples in the fields of water, air, wastes and sols.
est une notion anthropocentrique ; le même type d'événement peut, selon les époques, les milieux ... more est une notion anthropocentrique ; le même type d'événement peut, selon les époques, les milieux socioculturels, les stratégies ou les rôles individuels, être non souhaité pour les uns, paraître indiffèrent à d'autres et même souhaité par certains. » 2 Ce mot ne fait pas nécessairement référence à un unique individu. District minier Municipalités Département Produit minier Barrancas Barrancas,
Le terme « usine du futur » recouvre un certain nombre de concepts propres aux industries de tran... more Le terme « usine du futur » recouvre un certain nombre de concepts propres aux industries de transformation de la matière et de l’énergie par voies physico-biochimiques (industrie chimique, pharmacie, cosmétique, pétrole, métallurgie). Ces nouveaux concepts proviennent de la prise de conscience des pays développés de la nécessité de respecter l’environnement, tout en résistant à la compétition et à la globalisation des économies, et d’accompagner la société dans une transition postindustriell..
Parmi les reacteurs de generation IV, le GFR et le VHTR utilisent l'helium comme caloporteur.... more Parmi les reacteurs de generation IV, le GFR et le VHTR utilisent l'helium comme caloporteur. Il est necessaire de controler sa qualite chimique. Outre des impuretes radiochimiques et particulaires, il peut contenir H2, CO, CH4, CO2, H2O, O2 et des composes azotes, et doit etre purifie en permanence. Au CEA, un pilote permet d'etudier cette purification, realisee en trois etapes: oxydation de H2 et CO sur CuO, puis deux etapes d'adsorption. L'objectif est de fournir une analyse detaillee des deux premieres etapes, en les mettant en oeuvre a l'echelle du laboratoire. On montre a l'aide d'une premiere modelisation que la consommation du lit de CuO est totale, et en regime chimique. Les particules de CuO sont constituees de grains d'environ 200 nm de diametre. Un deuxieme modele, defini a l'echelle de ces grains, permet de trouver des resultats en accord avec les precedents. Un facteur d'echelle lie a la geometrie entre les constantes cinetiques ...
Cette these est consacree a l'etude du role de l'heterogeneite chimique dans le transport... more Cette these est consacree a l'etude du role de l'heterogeneite chimique dans le transport de solutes interactifs en milieux poreux satures. Il s'agit plus precisement de mettre en evidence l'augmentation de la dispersion d'un traceur lineairement interactif par rapport a la dispersion du traceur de l'eau. La methodologie experimentale consiste au tracage a l'echelle chromatographique de milieux modeles chimiquement heterogenes. Ces milieux, de sont constitues de deux phases solides : des grains inertes, et des grains impregnes de phase active disperses uniformement parmi les premiers. L'heterogeneite chimique depend de leur proportion en nombre dans le milieu. Plus ils sont nombreux, moins le milieu est heterogene. Les resultats experimentaux montrent que pour un comportement hydrodynamique similaire, la dispersion du traceur reactif est differente de la dispersion hydrodynamique, mais n'en est pas decouplee. Elle augmente lineairement avec l'echelle de l'heterogeneite chimique. Les termes dans la dispersion globale, dus respectivement a l'heterogeneite et a la cinetique de transfert sont decouples et simplement additifs. L'approche de modelisation des melangeurs en cascade a ete appliquee au transport en milieux heterogenes. La taille d'un melangeur qui determine la valeur du coefficient de dispersion du reactif est superieure a la taille d'un melangeur dans le cas du transport de l'eau. Les resultats obtenus par le modele sont tres coherents avec les constatations experimentales.
The demand for the new development of speci"c separation techniques for the treatment of drinking... more The demand for the new development of speci"c separation techniques for the treatment of drinking water leads to reexamining the use of cyclic operations in ion exchange processes. Establishing stable limit fronts inside the column is the required condition to allow the use of two-way chromatography methods and insure the process e$ciency. This paper presents numerical simulations and experimental validation at a laboratory pilot scale showing the development of a set of stationary composition pro"les during a cyclic operation of a chromatographic ion-exchange cyclic process. It has been shown numerically that stable cycles are obtained in the case where the cut points are chosen following a criterion based on the breakthrough volumes. The properties displayed by means of numerical simulations were experimentally validated. Reconstituted waters were treated by the cyclic process in order to selectively eliminate #uoride ion. The process uses two anion-exchange columns pre-equilibrated with the hydrogen carbonate anion in excess in the feed solution. After some cycles, steady concentrations of the major species (chloride and sulphate ions) are measured: a stable limit cycle is reached and the condition to (i) eliminate #uoride anion, (ii) restore the matrix of the other anions is ful"lled.
Selenium is a known toxic element released in the environment by anthropogenic activities. The pr... more Selenium is a known toxic element released in the environment by anthropogenic activities. The present study is devoted to the aqueous sorption behaviour of selenium oxyanions (selenate and selenite) on a reference oxide surface, namely rutile TiO(2). Batch sorption kinetics and isotherms have been studied using different physico-chemical conditions of the solution (changes of pH and ionic strength). The sorption was favoured for both anions in acidic conditions, in agreement with a surface complexation mechanism and CD-MUSIC predictions. Spectroscopic investigations of the sorbed rutile powder were also consistent with such a mechanism. EXAFS spectra confirmed that for selenite anions, an inner-sphere mechanism was the most probable process observed. Dynamic sorption experiments using a column filled with rutile powder also substantiated that a part of the surface complexes follows the inner-sphere mechanism, but also evidenced that an outer-sphere mechanism cannot be excluded, especially for selenate anions.
When pH buffers are used in frontal anion exchange chromatography, it is known that important tra... more When pH buffers are used in frontal anion exchange chromatography, it is known that important transient pH variations may occur, even if pHs are identical in preequilibration and feed. This effect was earlier studied with the aid of equilibrium theory extended to the case where dissociation reactions are involved. In the present paper, the sodium acetate/acetic acid system has been
Fast pyrolysis is a promising process for the preparation of bio-oil dedicated to energy valoriza... more Fast pyrolysis is a promising process for the preparation of bio-oil dedicated to energy valorization. The effects of inorganic species (K, Na, Ca, and Mg) on bio-oil stability are known, such as deposits, fouling or slagging issues. This study focuses on determination of the repartition of inorganic species in all pyrolysis products. Then we established an inorganic balance on liquid products in order to characterize the mass transfer of inorganic species from the insoluble residue to the bio-oil. Our data suggest that Na behavior is typically different from Ca, K and Mg. (Resume d'auteur)
It is shown how a simple gas tracer technique can contribute to the determination of transport ch... more It is shown how a simple gas tracer technique can contribute to the determination of transport characteristics of tight rock formations. Main obtained parameters are intrinsic permeability and the Klinkenberg coefficient; permeability as low as 10-21 m2 is easily attainable. Some information is also gained on diffusion characteristics and porosity. An example of application is given using caprocks from a deep saline aquifer in the Paris basin.
La directive europeenne, relative a la qualite des eaux destinees a la consommation humaine, impo... more La directive europeenne, relative a la qualite des eaux destinees a la consommation humaine, imposera une concentration maximale admissible pour le bore, dans les annees a venir, dont la valeur exacte est en cour de discussion, et sera vraisemblablement comprise entre 0,3 et 1 mg/l. Cet article recense la plupart des moyens d'eliminations du bore ayant ete testes. Les donnees presentees sont, soit le fruit d'une synthese bibliographique, soit les resultats d'experimentations menees conjointement par le L.H.R.S.P. et le L.S.G.C., soit enfin issues d'analyses d'echantillons preleves en entree et en sortie d'usine de potabilisation. Il en ressort que la plupart des traitements ne realisent que de faibles taux d'abattement, qui sont difficilement compatibles avec le respect de la future norme europeenne. Il n'existe, par consequent, a ce jour aucun procede d'elimination applicable de facon universelle, a l'echelle d'une filiere de potabilisati...
This paper presents a comparison between some numerical methods and techniques for solving the no... more This paper presents a comparison between some numerical methods and techniques for solving the nonlinear advection-dispersion equation, which may be used to describe the adsorption of phenol into a granular activated carbon fixed bed under local equilibrium conditions. The adsorption is described by the Langmuir isotherm, which makes the advection-dispersion equation nonlinear. This equation is solved successively by using the approximation and linearization techniques. For each technique, two types of numerical algorithms are used. Concerning the first one, the Implicit and the Runge Kutta schemes are used. As for the second one, the Modified Picard iteration and the Newton Raphson scheme are applied. Simulation results have been compared to each other and to the experimental data as well. Both of the Implicit and the Runge Kutta algorithms have led to superimposed simulated breakthrough curves. Both of the modified Picard and Newton Raphson schemes have given identical results too...
Soil and Sediment Contamination: An International Journal
ABSTRACT The transient transport of naphthalene through low organic matter content soil columns w... more ABSTRACT The transient transport of naphthalene through low organic matter content soil columns was investigated in different water-saturation and flow conditions. Some parameters were tested as flow rate, column height, and water saturation conditions. The soil was a clayed sandy soil from the Algerian coast near Boumerdes. The organic carbon content was 0.13% and the main mineral components were quartz (88%), clays minerals (7%) and calcite (3%). The height of the packing of the soil column (5.1 cm in diameter) varied from 15 to 40 cm. Simultaneous step injections of inert tracer (calcium chloride) and naphthalene at 10 mg L−1 were performed. Tracer and naphthalene breakthrough curves (BTCs) were measured continuously by conductimetry and UV – 220 nm, respectively. The BTCs were simulated using the classical mixing cells in series with exchange model (MCE). In unsaturated conditions the comparison of the mean residence time of tracer BTCs with the geometrical pore volume gave us access to average water saturation along the column as a function of height. The higher the soil bed was, the higher the mean water saturation. The comparison of naphthalene distribution coefficients (Kd) in different flow conditions with the theoretical value from the Karickhoff law showed that in saturated conditions the obtained value was close to the theoretical one. In unsaturated conditions, the measured naphthalene Kd's were much lower than the theoretical value and correlated to the water saturation.
Abstract Applications of microparticle systems in the oil industry are numerous: Microbial Enhanc... more Abstract Applications of microparticle systems in the oil industry are numerous: Microbial Enhanced Oil Recovery (MEOR), clay stabilization, fines migration and plugging of water injection wells are some of them. This paper addresses the importance of microparticle transient transport through natural porous media by proposing a new approach to quantify such transport. Under a slow flow regime, which is often the case in petroleum operations, particle retention due to mechanical effects can be neglected in comparison with colloidal interactions. Nevertheless, colloidal theory is mainly descriptive and quantitative prediction of particle adsorption in natural porous media has often led to a failure, particularly since homogeneous and heterogeneous equilibria were not taken into account. Batch and column experiments have been performed using a natural sand from Entraygues (France) and a living, non motile and no proliferating bacteria of the species Leuconostoc mesenteroides (L.m.) , dispersed in solutions with different ionic compositions. In addition, we modeled microparticle adsorption thanks to three phenomenological mechanisms: surface ionization, ion exchange and interfaces condensation (adsorption) at equilibrium. Most of batch experiments were successfully predicted by the model which provided a comprehensive and predictive approach for microparticle adsorption. The model was used to predict bacterial transport in a column (sandpack), assuming local equilibrium in conjunction with a lumped parameter flow model taking into account hydrodynamical dispersion in the porous medium. Though passable agreement was found between experimental and predicted elution curves, we discuss the validity of the model for predict in bacterial transport in natural porous media.
Durable ? Soutenable ? Sur le long terme ? Le développement durable est aujourd hui un enjeu qui ... more Durable ? Soutenable ? Sur le long terme ? Le développement durable est aujourd hui un enjeu qui préoccupe la société, mais aussi les scientifiques, et cela depuis de nombreuses années. Il concerne toutes les disciplines qui, chacune et ensemble, apportent les éléments pour observer, comprendre, modéliser et mieux anticiper l'avenir que réserve le changement global. C est donc avec enthousiasme que j ai soutenu ce projet, qui est l expression de l une des missions de l organisme de recherche, qu est le CNRS.
Numerous publications on the transport of pollutants in a fixed bed, in particular in the treatme... more Numerous publications on the transport of pollutants in a fixed bed, in particular in the treatment of waters still use two-parameter models: a capacity parameter measuring the delay of the breakthrough curve (CP) and a transfer kinetics parameter to translate the dispersion observed (Thomas model and Yoon-Nelson model), The authors totally neglect the role of the hydrodynamic dispersion which however largely contributes to the spread of the curves and thus the adjustments made on the analyzed breakthrough curves are invalid, Using three examples involving fixed beds of homogeneous adsorbent beads or sand, one of Lin et al [2013] with biochar-alginate grains (diameter 2.0 mm), the following from Jang et al. [2018] with resin beads (diameter 0.8 mm), and the last of our own work with a clay-limestone quartz sand of mean diameter 0.4 mm (Benaouag et al., 2018) we analyzed the validity of these models, For this we used as reference model a model with 4 parameters (Mixers in Cascade wit...
Modeling the non-equilibrium transport of linearly interacting solutes in porous media The transp... more Modeling the non-equilibrium transport of linearly interacting solutes in porous media The transport of linearly interacting solutes in porous media is investigated with the help of residence time distributions, transfert functions, methods of system dynamics, and time-moment analyses. The classical one-dimensional convection-dispersion equation is extended to two-region (mobile-immobile water) transport by including diffusional mass transfert limitations characteristic of aggregated porous media. The two region model is further revised by incorporating the effects of multiple retention sites (in parallel or in series), multiple porosity levels, and arbitrary but steady flow fields. It is shown that different physical situations can be represented by a relatively small number of transfert functions containing only two types of parameters : distribution coefficients to account for equilibrium properties, and characteristic times reflecting kinetic processes. Relevant kinetic processe...
Process engineering for environment protection The concepts and methodologies of the process engi... more Process engineering for environment protection The concepts and methodologies of the process engineering are useful and carry out for environment protection and sustainable development. Instead of an exhaustive presentation of the purification and treatment systems, this paper illustrates this approach by examples in the fields of water, air, wastes and sols.
est une notion anthropocentrique ; le même type d'événement peut, selon les époques, les milieux ... more est une notion anthropocentrique ; le même type d'événement peut, selon les époques, les milieux socioculturels, les stratégies ou les rôles individuels, être non souhaité pour les uns, paraître indiffèrent à d'autres et même souhaité par certains. » 2 Ce mot ne fait pas nécessairement référence à un unique individu. District minier Municipalités Département Produit minier Barrancas Barrancas,
Le terme « usine du futur » recouvre un certain nombre de concepts propres aux industries de tran... more Le terme « usine du futur » recouvre un certain nombre de concepts propres aux industries de transformation de la matière et de l’énergie par voies physico-biochimiques (industrie chimique, pharmacie, cosmétique, pétrole, métallurgie). Ces nouveaux concepts proviennent de la prise de conscience des pays développés de la nécessité de respecter l’environnement, tout en résistant à la compétition et à la globalisation des économies, et d’accompagner la société dans une transition postindustriell..
Parmi les reacteurs de generation IV, le GFR et le VHTR utilisent l'helium comme caloporteur.... more Parmi les reacteurs de generation IV, le GFR et le VHTR utilisent l'helium comme caloporteur. Il est necessaire de controler sa qualite chimique. Outre des impuretes radiochimiques et particulaires, il peut contenir H2, CO, CH4, CO2, H2O, O2 et des composes azotes, et doit etre purifie en permanence. Au CEA, un pilote permet d'etudier cette purification, realisee en trois etapes: oxydation de H2 et CO sur CuO, puis deux etapes d'adsorption. L'objectif est de fournir une analyse detaillee des deux premieres etapes, en les mettant en oeuvre a l'echelle du laboratoire. On montre a l'aide d'une premiere modelisation que la consommation du lit de CuO est totale, et en regime chimique. Les particules de CuO sont constituees de grains d'environ 200 nm de diametre. Un deuxieme modele, defini a l'echelle de ces grains, permet de trouver des resultats en accord avec les precedents. Un facteur d'echelle lie a la geometrie entre les constantes cinetiques ...
Cette these est consacree a l'etude du role de l'heterogeneite chimique dans le transport... more Cette these est consacree a l'etude du role de l'heterogeneite chimique dans le transport de solutes interactifs en milieux poreux satures. Il s'agit plus precisement de mettre en evidence l'augmentation de la dispersion d'un traceur lineairement interactif par rapport a la dispersion du traceur de l'eau. La methodologie experimentale consiste au tracage a l'echelle chromatographique de milieux modeles chimiquement heterogenes. Ces milieux, de sont constitues de deux phases solides : des grains inertes, et des grains impregnes de phase active disperses uniformement parmi les premiers. L'heterogeneite chimique depend de leur proportion en nombre dans le milieu. Plus ils sont nombreux, moins le milieu est heterogene. Les resultats experimentaux montrent que pour un comportement hydrodynamique similaire, la dispersion du traceur reactif est differente de la dispersion hydrodynamique, mais n'en est pas decouplee. Elle augmente lineairement avec l'echelle de l'heterogeneite chimique. Les termes dans la dispersion globale, dus respectivement a l'heterogeneite et a la cinetique de transfert sont decouples et simplement additifs. L'approche de modelisation des melangeurs en cascade a ete appliquee au transport en milieux heterogenes. La taille d'un melangeur qui determine la valeur du coefficient de dispersion du reactif est superieure a la taille d'un melangeur dans le cas du transport de l'eau. Les resultats obtenus par le modele sont tres coherents avec les constatations experimentales.
The demand for the new development of speci"c separation techniques for the treatment of drinking... more The demand for the new development of speci"c separation techniques for the treatment of drinking water leads to reexamining the use of cyclic operations in ion exchange processes. Establishing stable limit fronts inside the column is the required condition to allow the use of two-way chromatography methods and insure the process e$ciency. This paper presents numerical simulations and experimental validation at a laboratory pilot scale showing the development of a set of stationary composition pro"les during a cyclic operation of a chromatographic ion-exchange cyclic process. It has been shown numerically that stable cycles are obtained in the case where the cut points are chosen following a criterion based on the breakthrough volumes. The properties displayed by means of numerical simulations were experimentally validated. Reconstituted waters were treated by the cyclic process in order to selectively eliminate #uoride ion. The process uses two anion-exchange columns pre-equilibrated with the hydrogen carbonate anion in excess in the feed solution. After some cycles, steady concentrations of the major species (chloride and sulphate ions) are measured: a stable limit cycle is reached and the condition to (i) eliminate #uoride anion, (ii) restore the matrix of the other anions is ful"lled.
Selenium is a known toxic element released in the environment by anthropogenic activities. The pr... more Selenium is a known toxic element released in the environment by anthropogenic activities. The present study is devoted to the aqueous sorption behaviour of selenium oxyanions (selenate and selenite) on a reference oxide surface, namely rutile TiO(2). Batch sorption kinetics and isotherms have been studied using different physico-chemical conditions of the solution (changes of pH and ionic strength). The sorption was favoured for both anions in acidic conditions, in agreement with a surface complexation mechanism and CD-MUSIC predictions. Spectroscopic investigations of the sorbed rutile powder were also consistent with such a mechanism. EXAFS spectra confirmed that for selenite anions, an inner-sphere mechanism was the most probable process observed. Dynamic sorption experiments using a column filled with rutile powder also substantiated that a part of the surface complexes follows the inner-sphere mechanism, but also evidenced that an outer-sphere mechanism cannot be excluded, especially for selenate anions.
When pH buffers are used in frontal anion exchange chromatography, it is known that important tra... more When pH buffers are used in frontal anion exchange chromatography, it is known that important transient pH variations may occur, even if pHs are identical in preequilibration and feed. This effect was earlier studied with the aid of equilibrium theory extended to the case where dissociation reactions are involved. In the present paper, the sodium acetate/acetic acid system has been
Fast pyrolysis is a promising process for the preparation of bio-oil dedicated to energy valoriza... more Fast pyrolysis is a promising process for the preparation of bio-oil dedicated to energy valorization. The effects of inorganic species (K, Na, Ca, and Mg) on bio-oil stability are known, such as deposits, fouling or slagging issues. This study focuses on determination of the repartition of inorganic species in all pyrolysis products. Then we established an inorganic balance on liquid products in order to characterize the mass transfer of inorganic species from the insoluble residue to the bio-oil. Our data suggest that Na behavior is typically different from Ca, K and Mg. (Resume d'auteur)
It is shown how a simple gas tracer technique can contribute to the determination of transport ch... more It is shown how a simple gas tracer technique can contribute to the determination of transport characteristics of tight rock formations. Main obtained parameters are intrinsic permeability and the Klinkenberg coefficient; permeability as low as 10-21 m2 is easily attainable. Some information is also gained on diffusion characteristics and porosity. An example of application is given using caprocks from a deep saline aquifer in the Paris basin.
La directive europeenne, relative a la qualite des eaux destinees a la consommation humaine, impo... more La directive europeenne, relative a la qualite des eaux destinees a la consommation humaine, imposera une concentration maximale admissible pour le bore, dans les annees a venir, dont la valeur exacte est en cour de discussion, et sera vraisemblablement comprise entre 0,3 et 1 mg/l. Cet article recense la plupart des moyens d'eliminations du bore ayant ete testes. Les donnees presentees sont, soit le fruit d'une synthese bibliographique, soit les resultats d'experimentations menees conjointement par le L.H.R.S.P. et le L.S.G.C., soit enfin issues d'analyses d'echantillons preleves en entree et en sortie d'usine de potabilisation. Il en ressort que la plupart des traitements ne realisent que de faibles taux d'abattement, qui sont difficilement compatibles avec le respect de la future norme europeenne. Il n'existe, par consequent, a ce jour aucun procede d'elimination applicable de facon universelle, a l'echelle d'une filiere de potabilisati...
This paper presents a comparison between some numerical methods and techniques for solving the no... more This paper presents a comparison between some numerical methods and techniques for solving the nonlinear advection-dispersion equation, which may be used to describe the adsorption of phenol into a granular activated carbon fixed bed under local equilibrium conditions. The adsorption is described by the Langmuir isotherm, which makes the advection-dispersion equation nonlinear. This equation is solved successively by using the approximation and linearization techniques. For each technique, two types of numerical algorithms are used. Concerning the first one, the Implicit and the Runge Kutta schemes are used. As for the second one, the Modified Picard iteration and the Newton Raphson scheme are applied. Simulation results have been compared to each other and to the experimental data as well. Both of the Implicit and the Runge Kutta algorithms have led to superimposed simulated breakthrough curves. Both of the modified Picard and Newton Raphson schemes have given identical results too...
Soil and Sediment Contamination: An International Journal
ABSTRACT The transient transport of naphthalene through low organic matter content soil columns w... more ABSTRACT The transient transport of naphthalene through low organic matter content soil columns was investigated in different water-saturation and flow conditions. Some parameters were tested as flow rate, column height, and water saturation conditions. The soil was a clayed sandy soil from the Algerian coast near Boumerdes. The organic carbon content was 0.13% and the main mineral components were quartz (88%), clays minerals (7%) and calcite (3%). The height of the packing of the soil column (5.1 cm in diameter) varied from 15 to 40 cm. Simultaneous step injections of inert tracer (calcium chloride) and naphthalene at 10 mg L−1 were performed. Tracer and naphthalene breakthrough curves (BTCs) were measured continuously by conductimetry and UV – 220 nm, respectively. The BTCs were simulated using the classical mixing cells in series with exchange model (MCE). In unsaturated conditions the comparison of the mean residence time of tracer BTCs with the geometrical pore volume gave us access to average water saturation along the column as a function of height. The higher the soil bed was, the higher the mean water saturation. The comparison of naphthalene distribution coefficients (Kd) in different flow conditions with the theoretical value from the Karickhoff law showed that in saturated conditions the obtained value was close to the theoretical one. In unsaturated conditions, the measured naphthalene Kd's were much lower than the theoretical value and correlated to the water saturation.
Abstract Applications of microparticle systems in the oil industry are numerous: Microbial Enhanc... more Abstract Applications of microparticle systems in the oil industry are numerous: Microbial Enhanced Oil Recovery (MEOR), clay stabilization, fines migration and plugging of water injection wells are some of them. This paper addresses the importance of microparticle transient transport through natural porous media by proposing a new approach to quantify such transport. Under a slow flow regime, which is often the case in petroleum operations, particle retention due to mechanical effects can be neglected in comparison with colloidal interactions. Nevertheless, colloidal theory is mainly descriptive and quantitative prediction of particle adsorption in natural porous media has often led to a failure, particularly since homogeneous and heterogeneous equilibria were not taken into account. Batch and column experiments have been performed using a natural sand from Entraygues (France) and a living, non motile and no proliferating bacteria of the species Leuconostoc mesenteroides (L.m.) , dispersed in solutions with different ionic compositions. In addition, we modeled microparticle adsorption thanks to three phenomenological mechanisms: surface ionization, ion exchange and interfaces condensation (adsorption) at equilibrium. Most of batch experiments were successfully predicted by the model which provided a comprehensive and predictive approach for microparticle adsorption. The model was used to predict bacterial transport in a column (sandpack), assuming local equilibrium in conjunction with a lumped parameter flow model taking into account hydrodynamical dispersion in the porous medium. Though passable agreement was found between experimental and predicted elution curves, we discuss the validity of the model for predict in bacterial transport in natural porous media.
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Papers by Michel Sardin