Tesi sul tema "Colmatage de filtre"
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Benmachou, Kader Schmitz Philippe Meireles-Masbernat Martine. "Étude et modélisation du colmatage d'un filtre plissé". Toulouse : INP Toulouse, 2008. http://ethesis.inp-toulouse.fr/archive/00000698.
Benmachou, Kader. "Étude et modélisation du colmatage d'un filtre plissé". Toulouse, INPT, 2005. https://hal.science/tel-04582023.
The purpose of this work is to develop an approach to simulate numerically the behaviour of the pleated filters, and thus limit the number of experimental tests. The first part of this work concerns the analysis and the modelling of filtration through fibrous media. An experimental study relating to the microstructure of fibrous media and its filtration capacities was carried out. Then, assuming that the particles are captured by sieving, a clogging model was developed. This model describes well the two successive phases of clogging observed in the experiments namely depth filtration and cake filtration. In a second part, the fluid flow, the particle transport and capture are studied and modelled in an elementary pleat and within the complete filter. The validation of the model is carried out by considering both experimental results and CFD simulations using Fluent®. The results are discussed according to the geometrical characteristics of the filter element
Gervais, Pierre-Colin. "Études expérimentale et numérique du colmatage de filtre plissé". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0007/document.
Pleated filters are widely used in air treatments because of the advantageous effective surface to overall dimension ratio they offer. Their major drawback though resides in their reduced lifetime which still needs to be controlled. Indeed, when clogging, the pressure drop considerably increases, the filtration flow is then no longer maintained which might lead to the deterioration of the media. It is then crucial to characterize the evolution of the pressure drop under operating conditions in order to best design these equipments. Part of our work consisted in studying how the operating conditions influence the geometry of the deposit. To do so, we used Single-Photon Emission Computed Tomography (SPECT), a non-destructive imaging technique that keeps intact the particle structuring. The visualization of aerosol deposit at the beginning of the filtration process allows observing preferential particle deposition on the whole height of the pleat. A numerical approach was used to study the permeability of bimodal fibrous media and we experimentally studied the local velocity as well as the biphasic flow inside pleated filter media. Comparison between experiments and simulations allowed us to validate the Geodict code for a wide range of media properties and velocities. Regarding bimodal fibrous media, the fast data acquisition has allowed testing several existing models which resulted in classifying them in a unique way. If the experimental results on the initial deposition in pleated filters are encouraging, those related to beforehand clogging point to several improvements regarding the technique we used
Rolland, Laurence. "Analyses comparatives de systèmes d'infiltration-percolation : colmatage et outils de diagnostics". Montpellier 2, 2009. http://www.theses.fr/2009MON20132.
Seepage beds are widely used for on-site and small communities wastewater treatment. These extensive systems present the advantages of both an easy management and good treatment performances. However, they are sensitive to the physical and biological clogging. Clogging alter the treatment performances but also reduce the service life. The role of materials and conception of filters on the control of the permeability of the filtering bed and regulation of the biomass accumulated remain badly understood. In addition, there is a lack of non-destructive tools in order to perform diagnosis on operating systems. The aim of this thesis is to analyse (at various scales and with different tools, especially non-destructive) the answer of infiltration systems to varying operating conditions that are, namely: (i) the composition of the influent, the seepage bed design (type of sand and its implementation, the presence of a geogrid at the bottom), but also (ii) of the operating parameters (hydraulic load, organic load, and mode of feeding). Results highlight the determining roles (i) of the grain size distribution on hydraulic behaviour and the retention of suspended solids, (ii) and of the feeding mode and organic loads. We estimate the operating state of the systems at different time. We distinguish several non-destructive tools fitted for the diagnosis: the measurement of the gaseous oxygen within soil porosity, the measurement of electrical resistivity. In addition, we determine threshold values that allow to differentiate the different state of the system operation
Rebaï, Mehdi. "Analyse et modélisation de l'écoulement et du colmatage d'un filtre à air pulsé". Toulouse, INPT, 2007. http://ethesis.inp-toulouse.fr/archive/00001553/.
The main objective of this work is the development of a numerical tool allowing the prediction of the clogging of a pleated fibrous filter for air filtration. The study is based on a multi-scale approach from the fiber scale to the pleated filter scale. The work is divided into two parts. The first one deals with the flow field (without particles) inside the fibrous medium and the pleat. The flow model inside a pleat is based on the assumption of a similarity solution. The second part is devoted to the clogging model of a pleated filter, which is obtained by combining the clogging model for a flat fibrous media with the flow model inside the pleat. Clogging of pleated filter is studied with this model, which can also be considered as a computational sizing and design tool. Using the model will reduce the number of trials and therefore the overall time of pleated filter design
Gaillard, Fabrice. "Etude du comportement d'un filtre à gaz autonettoyant par fluidisation". Chambéry, 2003. http://www.theses.fr/2003CHAMS022.
The production of gas of great purity usually requires use of high effectiveness filters, wich change with the time, imposing the need for periodic replacement when they are clogged or their sequential unclogging. Some researches developed on the adjustment of processes allow to control or to limit the clogging of the filter. It is for example the case of the tangential filtration and continuous cleaning by ultrasounds or shock waves. In our study, the process considered is the coupled use of fluidization and filtration. The interest of this process lies in the fact it allows the filtration of a gas while controling the clogging of the filter medium by the action of the fluidized particles friction on it. As a result, only a fraction of the gas is filtered, whereas the remaining one goes over through the bed to maintain the fluidization. The filter zone can occupy the whole or part of the fluidized bed. It can consist of filter elements immersed in the bed or by elements forming the walls of the bed. So, a parallel assembly, like a filter press employed in water treatment, can be used. The flow of a part of the gas through the filter medium leads to a vertical velocity gradient, which modifies the aspect of the fluidization and leads to a particular hydrodynamics of this process. The principle of the process is the following : the gas to be treated enters the lower part of the module. The grains of the bed, fluidized by the inflowing gas, are imparted a random movement. Some grains therefore come into contact with the filter wall. By rubbing on this wall they scrape the particle cake, therby limiting its formation on the filter surface. The aggregates of particles removed from the filter wall are then entrained towards the top of the bed. Consequently, part of the gas passing trough the filtering element is totally purified while the remaining fraction of the gas crosses the entire heigh of the fluidized bed and it concentrates in particles
Le, Maout-Alvarez Coralie. "Étude expérimentale des effets chimiques sur le colmatage des filtres dans l’industrie nucléaire". Electronic Thesis or Diss., Université de Lorraine, 2023. http://docnum.univ-lorraine.fr/ulprive/DDOC_T_2023_0015_ALVAREZ.pdf.
During a LOCA accident (Loss Of Coolant Accident) occurring to a nuclear Pressurized Water Reactor (PWR), debris are generated and can be partially transported to the RIS-EAS filter in the sumps located in the bottom of the nuclear reactor containment. These debris can contribute to the « physical » clogging of the filters. Another effect called « chemical effects » corresponds to the presence of cations in solution resulting from the debris' corrosion and the possible corrosion of the metal surface present in the reactor containment vessel. In the case of a severe accident with core fuel meltdown, additional loads debris are to be considered as presence of particles formed of structural materials, control rod material, fission products and concrete particles resulting from corium-concrete interaction. To ensure the long term liquid recirculation functionality, the chemical effect have to be understood: nature of these chemical effects, conditioning parameters and potential effect on the clogging. The thesis aims at studying the chemical effects after designing a dedicated experimental loop: a parametric approach , coupled with several chemical and pressure drop measurements. Chemical speciation in solution and precipitate characterizations will/can be respectively performed by ICP and MEB-EDX, DRX and XPS techniques
Bessière, Yolaine. "Filtration frontale sur membrane : mise en évidence du volume filtre critique pour l'anticipation et le contrôle du colmatage". Toulouse 3, 2005. http://www.theses.fr/2005TOU30142.
Castaing, Jean-Baptiste. "Procédés de traitement de l'eau de mer en conchyliculture pour la sauvegarde et le maintien de la qualité des mollusques bivalves". Nantes, 2011. http://archive.bu.univ-nantes.fr/pollux/show.action?id=4e84b101-063c-4e23-81e3-061f5f18860e.
The aim of this work is the study of seawater filtration process to preserve commercial bivalves and maintain their quality during harmful algal blooms. The originality of this work is based on the study of rustic processes, capable of removing toxic microalgae from seawater. Two filtration processes have been studied, the immersed hollow fibres membranes and a sand filter. The origin and nature of fouling mechanisms have been identified in connection with the selectivity and energy consumption. Suspensions of toxic and nontoxic microalgae were reconstituted and then filtered through 10 kDa, 300 kDa and 0. 2 μm membranes and a sand filter (mean grain diameter “dg” equal to 250-520 μm). Microfiltration membrane 0. 2 μm has emerged as the most suitable for the filtration of seawater : more than 99 % of micro-algae were eliminated for a specific energy consumption below 0. 5 kWh/m3. Fouling mechanisms were investigated by membranes autopsies and the use of membrane filtration models. Sand filtration does not allow to retain all microalgae. Nevertheless, a decrease in the average size of sand grains significantly increases the toxic micro-algae retention (Rejection rate equal to 90 % after 6 h of filtration with dg = 256 μm). Sand filtration does not allow a total retention of toxic microalgae, then it can only be proposed as a seawater pretreatment system before membrane filtration. Despite a higher cost, immersed hollow fibres membranes can be considered for the protection of shellfish basins
Farkouh, Bassam. "Le filtre géosynthétique dans les ouvrages de drainage : essais de laboratoire et observations in situ". Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10204.
Boudhan, Rachid. "Performance of pulse-jet bag filter regarding particle removal for nano-waste incineration conditions". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0022/document.
Filtration performance of a pulse-jet bag filter was evaluated at the laboratory-scale regarding submicronic particles with a nanosized fraction during clogging/unclogging cycles. The particle size distribution was representative to those encountered at the outlet of a nano-waste incineration device at laboratory-scale. The bag filter was operated in conditions as similar as possible to those found in flue gas treatment of waste incineration plants, in terms of temperature, humidity, filtration velocity, injection of sorbent reagents and unclogging conditions. The air flow and the bag filter were heated to 150°C, the water content was maintained in the air flow in the range of 10-12% (3% of relative humidity RH), and filtration velocity throughout the bag filter was fixed at 1.9 cm.s⁻¹. A mixture of submicronic suspended particles of activated carbon and sodium bicarbonate, both used in flue gas treatment systems mainly for the removal of dioxins/furans and acid gases, was generated simultaneously with the aerosol representative of combustion emissions.The study focused on the filtration performance at the beginning of the bag filter’s lifetime filter for the 11 first clogging-unclogging cycles before stabilizing the residual pressure drop reached after pulse-jet unclogging. The maximum pressure drop was set at 150 Pa for all filtration cycles. Once the maximum pressure drop was reached, the filter was unclogged using the pulse-jet system. The performance of the bag filter was evaluated in terms of the evolution of pressure drop, fractional and total particle collection efficiencies, during the clogging/unclogging cycles.Moreover, an experimental and theoretical study was carried out on the influence of different parameters on the filtration performance of bag filter and flat filter, such as influence of humidity (3% RH versus 0% RH at 150°C), temperature (150°C versus 24°C), filtration velocity (1.9 cm.s⁻¹ versus 1.4 cm.s⁻¹) and the influence of the injection of sorbent reagents.The main results of this study are: (i) high collection efficiency of the bag filter in representative conditions of flue gas treatment of waste incineration: minimun particle collection efficiency of 98.5% for particle diameter of 74 ± 15 nm (electrical mobility diameter), (ii) influence of residual particle cake at the beginning of the filtration cycles on the bag filter performance, (iii) significant influence of humidity on the porosity of the particle cake due to the capillary condensation of water between the particles in presence of humidity (150°C - 3% RH i.e. almost 100 g of water per kg of dry air). Faster increase of bag filter pressure drop in presence of humidiy (150°C - 3% RH) as compared to the dry conditions (150°C - 0% RH)
Bourrous, Soleiman. "Étude du colmatage des filtres THE plans et à petits plis par des agrégats de nanoparticules simulant un aérosol de combustion". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0301/document.
In nuclear facilities, airborne particles are the vector of most of the radiological contamination. For this reason, pleated HEPA filters are one of the containment devices which are actively studied by the IRSN (Institut de Radioprotection et de Sûreté Nucléaire) to ensure the safety of nuclear exploitation. To avoid contamination of the environment, the understanding of the behavior of the filters especially in accidental situation has to be as exhaustive as possible. The most probable accident and the most penalizing for the containment devices is fire which leads to a massive soot particle production. In this case, the clogging of the filters is a problematic which has to be taken into account. Up to now, an empirical correlation has been developed to predict the pressure drop increase. The empirical nature of this correlation doesn’t allow its use in all situations. A phenomenological understanding and model of the clogging is then necessary. The following PhD work aims to reduce the pressure drop evolution to physical observations for each step of the clogging in order to model it on the most physical basis as possible. To do so, the study has been divided in two parts. The first one focusing on the behavior of flat filter by measuring the penetration of particles inside the medium and the porosity of the deposit formed on its surface. In the second part a small scale experiment based on a single pleat has been developed. Accumulation of the particles inside the pleat has been directly observed, deformation of the pleat as well as airflow in the pleat (using a PIV method) has been measured. During these experiments, pressure drop has been monitored and the measured parameters have been linked to the pressure drop evolution. Finality is to build a simple analytical model to predict the pressure drop evolution of the filters as a function of the deposited mass, the aerosol characteristics and the ventilation conditions. The main perspective opened by these results is the validation of complete numerical models to overcome the experimental limits. The logical extension of this work will be the study of the interaction of a clogged filter with temperature, air moisture and chemical aggression
Lecoq, Marie. "Étude du colmatage de filtres métalliques par un aérosol liquide". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0006.
Industrial installations often contain hazardous materials in aerosol form. High efficiency filters (HEPA) are usually the last barrier that ensure the containment of these airborne particles. In the nuclear industry, a large amount of radioactivity is handled in liquid form, that may release, in few scenarios, liquid aerosols. These particles may affect the performance of HEPA filters with a huge increase of the pressure drop, which lead in return to a significant reduction of the ventilation flowrate. In such scenarios the pressure drop increase may exceed the filter mechanical strength and induce degradations of the media and leading to a deterioration of its capacity to retain aerosol pollutants. To overcome this problem, and to protect HEPA filter, one of the solutions is to use pre-filter (more mechanically resistant but less efficient) made up with metallic fibers. To validate this approach, it is necessary to study the behavior of these prefilters, composed of a stack of different monolayers of media. In my work, I first focused on the clogging of industrial prefilters with liquid aerosol particles. Then, for a more analytical study, I study the clogging each layer separately, in order, to model, on the future, the behavior of the assembly. The microphysical of each media (thickness, packing density, and fiber size distribution) are determined. The evolution of both filter collection efficiency and pressure drop are studied along the clogging by a submicron liquid aerosol DEHS, for different filtration velocity (0,9 à 18 cm/s). For monolayer filters, I measure pressure drops in line with the previous results found in the literature. These experiments first highlight a quasi-linear increase of the pressure drop, associate with a collection of the droplets by the fibers. Then an exponential growth is measures, that corresponds to the clogging of the pores. And finally, an abrupt stabilization is observed corresponding a liquid film formation and its continuous drainage by the airflow. However, I show a more gradual stabilization for multilayer filters. A clogging scenario is proposed, and a simplistic model is established to forecast the pressure drop as a function of the mass of liquid accumulated. To this aim, I develop a new method to freeze the liquid accumulation using resin, that where further analyze using X-ray tomography
DEL, FABBRO LAETITIA. "Modelisation des ecoulements d'air et du colmatage des filtres plisses par des aerosols solides". Paris 12, 2001. http://www.theses.fr/2001PA120010.
Bessiere, Yolaine. "Filtration frontale sur membrane : mise en évidence du volume filtré critique pour l'anticipation et le contrôle du colmatage". Phd thesis, Université Paul Sabatier - Toulouse III, 2005. http://tel.archives-ouvertes.fr/tel-00143769.
Penicot-Bauge, Pascale. "Étude de la performance de filtres à fibres lors de la filtration d'aérosols liquides ou solides submicroniques". Vandoeuvre-les-Nancy, INPL, 1998. http://docnum.univ-lorraine.fr/public/INPL_T_1998_PENICOT_BAUGE_P.pdf.
Burešová, Hana. "Výzkum regenerace filtračního materiálu zemních filtrů a kořenových čistíren odpadních vod". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225490.
Blais-Gagnon, Arianne. "Évaluation de la performance des drains et des matériaux filtrants à ralentir le colmatage et l'ensablement en sol sableux et ferreux". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27123.
In Quebec, drains installed in sandy loam soils are susceptible to clogging by silt and/or by iron ochre. In the past, drains with slot widths smaller than 2 mm were used with a woven filter of 110 microns or knitted filter of 450 microns. Recently, drains with slot widths larger than 2 mm and a filter of 250 microns were introduced on the market but have never been tested. The project aimed to determine the speed at which silting and iron clogging will happen for different combinations of drains (slot widths 1,8 mm and 3 mm) and filters (110 μm, 250 μm et 450 μm) in a Becancour’s sandy soil. An experimental randomized complete block (3) design was used. The flow rates were measured at the outlet of each experimental plot and the heights of water table were measured with a bubbler in piezometers. The monitoring of physicochemical parameters (pH, redox potential and Fe2+ content) was performed in ground water and water from the drain outlet. The drains excavated 13 months after their installation only show traces of sediments and of iron ochre. Concentrations in Fe2+ are significantly lower in the water from the outlet drains than water from the ground water table. Iron clogging process seems to begin and its impacts are not measurable in terms of flow rates at the drain outlets.
Alilou, Youssef. "Impact sur le colmatage en régimes transitoire et permanent des écoulements d’air induits par le plissage des médias filtrants THE". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0047/document.
High Efficiency Particulate Air (HEPA) pleated filters are used to ensure the containment of airborne contamination within nuclear facilities. These filters are often the last barrier before a potential release of radioactive substances into the environment. Predicting their performances (pressure drop and efficiency) is a main thrust of research for IRSN which aims at avoiding any unexpected failure of those devices on French nuclear facilities. The clogging phenomenon is mainly influenced, on one side, by the flow conditions imposed in the ventilation network and, on the other side, by the media characteristics and the particles properties which are collected by the filter. Consequently, the work carried out has been divided into two parts. In the first part, we focused on the study of the airflow behavior within a HEPA pleated filter with an experimental and numerical approach. An experimental bench has been developed to measure the airflow field at the entrance channel of a HEPA filter pleat. Then, the experimental measurements have been used to validate GeoDict® and ANSYS CFX® simulations. The combination of the experimental and the numerical results have been used to develop a model to predict the evolution of the initial HEPA filter pressure drop. The work performed in the second part deals with the clogging of the filter. An experimental bench, dedicated to the characterization of the parameters that intervene in the clogging models such as the porosity, the pressure drop and the particles size, has been developed. Then, numerical simulations conducted with GeoDict® have been realized to describe the cake formation on the surface of a HEPA pleated filter. Finally, we developed a model to predict the evolution of HEPA pressure drop during clogging with micronic particles
Grippari, Florence. "Caractérisation et filtration des aérosols nonastructurés : application aux fumées de projection thermique des métaux". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0158/document.
This study deals with the filtration of metallic particles contained in the metallization fumes. Experience feedback specific to the filtration of metallization fumes by dust collectors report a rapid clogging of filters and the inefficiency of pneumatic cleaning techniques commonly used. This leads to a high reduction in filters lifetime. The objective of this study is characterize clogging then unclogging in order to improve the performance of dust cartridge filter against metallization fumes. Three research axes were explored on a dedicated bench : - Metallization fumes characterization. It allows describing the spatial structure of the particle by the fractal dimension and the dynamic shape factor with the DMA-ELPI serial coupling and thanks to an original data analysis methodology validated on various aerosols. The characteristics obtained explain the clogging properties of metallization fumes. - Characterization of the cake generated during the filtration phase (or clogging). It shows a incompressible structure in the velocities filtration range of industry. The experimental porosity of the cake formed by filtering metallization fumes is estimated thanks to these studies. - Study on cleaning. It describes and explains the inefficiency of pneumatic cleaning techniques employed in industry. It appears that only a very small surface of the pleated media is unclogged. The precoating alternative is shown to be very efficient provided that it is combined with off-line cleaning procedures
Gaveau, Arthur. "Etude des mécanismes de transfert de bactéries déformables en microfiltration frontale". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30046/document.
Membrane filtration is a separation technique commonly used as a method for removing and extracting microorganisms present in a fluid. The selectivity mechanism is size exclusion. However, our work has highlighted transfer of microorganisms through the porous membrane structure during filtration operations, even if the size of the living cell in suspension is greater than the average pore size of the membrane, resulting in lowering of the accumulation rate of the microorganisms and thus contamination of the permeate phase. Morphological and nanomechanical characterization of selected bacteria cells used for our work were performed and the properties of the model membrane were analyzed. With this information, the transfer of bacteria dunring the first moments of the dead-end filtration has been evaluated and the role of operating parameters (type of bacteria strains, physicochemical composition of filtered fluid, TMP) has been studied. Thus, our results have clarified the selectivity mechanisms applied to Gram-positive and Gram-negative bacteria strains because of different structural characteristics of the bacterial cell wall (thickness and elasticity of the peptidoglycan layer). Finally, evolution of cells transfer to the permeate phase has also been followed, and the bacterial deposit clogging the membrane was observed. The role of the structured deposit on the variations in flow and transfer has been demonstrated for the three selected bacterial models. Our results have defined critical conditions (physical, chemical and biological) where the transfer of bacterial cells is amplified by deformation during a frontal membrane filtration
Benmachou, Kader. "Etude et modélisation du colmatage d'un filtre plissé". Phd thesis, 2005. http://oatao.univ-toulouse.fr/7750/1/benmachou.pdf.
Rebaï, Mehdi. "Analyse et modélisation de l'écoulement et du colmatage d'un filtre à air plissé". Phd thesis, 2007. http://oatao.univ-toulouse.fr/7085/1/rebai1.pdf.