Rebai M.,National Polytechnic Institute of Toulouse |
Rebai M.,French National Center for Scientific Research |
Prat M.,National Polytechnic Institute of Toulouse |
Prat M.,French National Center for Scientific Research |
And 5 more authors.
Chemical Engineering Science | Year: 2010
A semi-analytical model of gas flow in pleated fibrous filters is developed for large filtration velocities. This case presents two main new and distinguishing features compared to the low filtration velocity situations studied in previous works: the velocity profiles are not parabolic within the pleat channels and the filtration velocity is not uniform along the pleated filter element and this has a great impact on the filter loading. The model relies on similarity solutions to the Navier-Stokes equations in the channels formed by pleating the filter medium. After validation by comparison with direct CFD simulations and experimental data, the model is used to determine the optimal pleat density, i.e. the pleat density minimizing the overall pressure drop across the filter for given flow rate, pleat length and given filter medium properties. As illustrated in the paper, this model greatly facilitates the study of flow within the pleated filter compared to a standard CFD approach. It represents an excellent basis for the more involved problem of filter loading computation. In particular, no remeshing across the width of the pleated filter entrance channels is needed when a filtration cake forms at the channel walls. © 2010 Elsevier Ltd. All rights reserved.
Liu Y.,National Polytechnic Institute of Toulouse |
Liu Y.,French National Institute for Agricultural Research |
Liu Y.,French National Center for Scientific Research |
Tourbin M.,Laboratoire Of Genie Chimique |
And 5 more authors.
Powder Technology | Year: 2014
The increasing use of nanoparticles will inevitably result in their release into the aquatic environment and thereby cause the exposure of living organisms. Due to their larger surface area, high ratio of particle number to mass, enhanced chemical reactivity, and potential for easier penetration of cells, nanoparticles may be more toxic than larger particles of the same substance. Some researchers have been showing some relations between nanoparticles and certain diseases. However, the doses, surface shapes, material toxicity and persistence of nanoparticles may all be factors in determining harmful biological effects. In order to better evaluate their risks, potential exposure route of nanoparticles has to be taken into consideration as well. Finally, a brief summary of techniques for nanoparticle removal in waters and wastewaters is presented, but it seems that no treatment can absolutely protect the public from exposure to a large-scale dissemination of nanomaterials. © 2013.
Botet R.,University Paris - Sud |
Roger K.,CNRS Chemical Engineering Laboratory |
Roger K.,Laboratoire Of Genie Chimique
Current Opinion in Colloid and Interface Science | Year: 2016
Nanoprecipitation provides colloidal dispersions through successive recombination events between nanometric objects. In the present article, we explain why the nanoprecipitation pathways induced through solvent-shifting - the Ouzo effect -, are fascinating study-cases. Indeed, they allow to address the question of how the interactions between the colloidal particles control the dynamics of the process, thus the particle size distribution. Experimental monitoring of the precipitation dynamics demonstrates that the colloidal dispersion polydispersity decreases over time as the droplets coalesce. Monte Carlo simulations within the Smoluchowski framework agree quantitatively with these observations, and show how the interactions between the particles naturally force the system to become nearly monodisperse. The mechanistic understanding gained from the solvent-shifting experiments is also relevant to other nanoprecipitation processes. © 2016 Elsevier Ltd.
Gomez A.,Laboratoire Of Genie Chimique |
Pibouleau L.,Laboratoire Of Genie Chimique |
Azzaro-Pantel C.,Laboratoire Of Genie Chimique |
Domenech S.,Laboratoire Of Genie Chimique |
And 2 more authors.
Energy Conversion and Management | Year: 2010
Development of a technico-economic optimization strategy of cogeneration systems of electricity/hydrogen, consists in finding an optimal efficiency of the generating cycle and heat delivery system, maximizing the energy production and minimizing the production costs. The first part of the paper is related to the development of a multiobjective optimization library (MULTIGEN) to tackle all types of problems arising from cogeneration. After a literature review for identifying the most efficient methods, the MULTIGEN library is described, and the innovative points are listed. A new stopping criterion, based on the stagnation of the Pareto front, may lead to significant decrease of computational times, particularly in the case of problems involving only integer variables. Two practical examples are presented in the last section. The former is devoted to a bicriteria optimization of both exergy destruction and total cost of the plant, for a generating cycle coupled with a Very High Temperature Reactor (VHTR). The second example consists in designing the heat exchanger of the generating turbomachine. Three criteria are optimized: the exchange surface, the exergy destruction and the number of exchange modules. © 2009 Elsevier Ltd. All rights reserved.
Haddou B.,Oran University of Science and Technology - Mohamed Boudiaf |
Guitri N.,Oran University of Science and Technology - Mohamed Boudiaf |
Debbab A.,Oran University of Science and Technology - Mohamed Boudiaf |
Gourdon C.,Laboratoire Of Genie Chimique |
Derriche Z.,Oran University of Science and Technology - Mohamed Boudiaf
Separation Science and Technology | Year: 2011
The aim of this work was to compare two synthetic dyes, Orange G (7-Hydroxy-8-(phenylazo)-1,3-naphthalenedisulfonic acid, disodium salt) and Orange II (p-(2-Hydroxy-1-naphthylazo) benzenesulfonic acid, sodium salt), towards cloud point extraction from colored water. Three commercial non-ionic surfactants were used in this work: Oxo-C15E7, Oxo-C10E3, and Triton X-100. The experimental extraction results were expressed by the following three responses: percentage of the extracted dye (E), residual concentrations of dye in the dilute phase (Xs,w), and the volume fraction of coacervate (φC) at the equilibrium. The results obtained for each parameter were represented on three dimensional diagrams using an empirical smoothing method. In optimal conditions Orange II concentration in the effluent was reduced to about 227 times, whereas E did not exceed 55% using Oxo-C15E7 in the case of Orange G extraction. However, when a small amount (0.025 wt.%) of cetyltrimethylammonium bromide (CTAB) was combined with Oxo-C10E3 as a mixed micelles system, the results showed that the extraction percentage of Orange G increased from 55 to 98%. Indeed, the concentration of this dye in the effluent was reduced to about 400 times. Finally, the extraction extent of both dyes was found to be low at basic pH, which may be useful for surfactant regeneration. © Taylor & Francis Group, LLC.
Klamklang S.,Laboratoire Of Genie Chimique |
Klamklang S.,Chulalongkorn University |
Vergnes H.,Laboratoire Of Genie Chimique |
Senocq F.,CNRS Inter-university Material Research and Engineering |
And 3 more authors.
Journal of Applied Electrochemistry | Year: 2010
In this research, the specific electrodes were prepared by metal-organic chemical vapor deposition (MOCVD) in a hot-wall CVD reactor with the presence of O2 under reduced pressure. The Ir protective layer was deposited by using (Methylcyclopentadienyl) (1,5-cyclooctadiene) iridium (I), (MeCp)Ir(COD), as precursor. Tetraethyltin (TET) was used as precursor for the deposition of SnO2 active layer. The optimum condition for Ir film deposition was at 300 C, 125 of O2/(MeCp)Ir(COD) molar ratio and 12 Torr of total pressure. While that of SnO2 active layer was at 380 C, 1200 of O2/TET molar ratio and 15 Torr of total pressure. The prepared SnO2/Ir/Ti electrodes were tested for anodic oxidation of organic pollutant in a simple three-electrode electrochemical reactor using oxalic acid as model solution. The electrochemical experiments indicate that more than 80% of organic pollutant was removed after 2.1 Ah/L of charge has been applied. The kinetic investigation gives a two-step process for organic pollutant degradation, the kinetic was zero-order and first-order with respect to TOC of model solution for high and low TOC concentrations, respectively. © Springer Science+Business Media B.V. 2009.
Elgue S.,Safran |
Conte A.,Safran |
Gourdon C.,Laboratoire Of Genie Chimique |
Bastard Y.,Axyntis Group
Chimica Oggi/Chemistry Today | Year: 2012
Direct fluorination of an Axyntis® 1,3-dicarbonyl compound is investigated at industrial scale in a commercial continuous flow reactor under gas-liquid conditions. The considered flow reactor manufactured by Boostec®, is made of silicon carbide that offers relevant heat transfer performances with regards to reaction exothermicity, as well as corrosion resistance. A screening of the operating conditions and more precisely on solvent and on catalyst was performed to demonstrate the feasibility of the reaction in a continuous mode. To work in a safe and non-hazardous environment regarding the reaction characteristics, experiments have been carried out at the MEPI facility (Maison Européenne des Procédés Innovants). The results show that in slug flow regime full conversion could be achieved with few seconds residence time while reaching a productivity level about 200 g per hour.
Filali A.,Toulouse 1 University Capitole |
Manas A.,Toulouse 1 University Capitole |
Mercade M.,Toulouse 1 University Capitole |
Bessiere Y.,Toulouse 1 University Capitole |
And 2 more authors.
Biochemical Engineering Journal | Year: 2012
Two granular sludge sequencing batch reactors (GSBR) with alternating anoxic/aerobic (R1) and anaerobic/aerobic (R2) conditions were operated with a 4-carbon-source synthetic influent. The physical properties of the granular sludge were very good (SVI≈20mLg -1) and high solid concentrations (up to 35gL -1) were obtained in the bioreactor operated with a pre-anoxic phase with additional nitrate (R1). In contrast, performance and granule settleability were lower in R2 due to the development of filamentous heterotrophic bacteria on the surface of granules. These disturbances were linked to the fact that a fraction of COD remained during the aerobic phase, which was not stored during the anaerobic period. To stabilize a GSBR with a mixture of organic carbon sources, it is thus necessary to maximize the amount of substrate used during the non-aerated, anaerobic or anoxic, phase. Comparable phosphate removal efficiency was observed in both systems; enhanced biological P removal being greater in anaerobic/aerobic conditions, while the contribution of precipitation (Ca-P) was more significant in anoxic/aerobic conditions. © 2012 Elsevier B.V.
Comtat M.,Laboratoire Of Genie Chimique
Actualite Chimique | Year: 2015
With Henri Pitot, Paulin Talabot, Henri Merle and Paul Rivals are evocated some mutations of the society in Provence, the beginning of industrialisation, the history of soap and aluminium and the construction of the Faculty of Sciences in Marseille.
Meklat A.,British Petroleum |
Bouras N.,British Petroleum |
Zitouni A.,British Petroleum |
Mathieu F.,Laboratoire Of Genie Chimique |
And 5 more authors.
Extremophiles | Year: 2012
A halophilic actinomycete strain designated H19T, was isolated from a Saharan soil in the Bamendil region (Ouargla province, South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Actinopolyspora, and 16S rRNA gene sequence analysis confirmed that strain H19T was a novel species of the genus Actinopolyspora. DNA-DNA hybridization value between strain H19T and the nearest Actinopolyspora species, A. halophila, was clearly below the 70 % threshold. The genotypic and phenotypic data showed that the organism represents a novel species of the genus Actinopolyspora for which the name Actinopolyspora algeriensis sp. nov. is proposed, with the type strain H19T (= DSM 45476T = CCUG 62415T). © 2012 Springer.