• 专利附录
  • 专利说明
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    • 专利摘要:
    Filter for the filtration of a liquid, comprising or consisting of a support element made of a porous ceramic material and a membrane separating layer for the filtration of said liquid, said support element being covered on the part of its surface in contact with the liquid to be filtered by said membrane separating layer, said separating layer being made of a material comprising at least 70% by weight of silicon carbide SiC with respect to the total weight of all the inorganic compounds present in said separating layer, said filter being characterized in that the ratio between the molar SiC content in the beta form and the molar SiC content in the alpha form is greater than 0.5.
    公开号:FR3052682A1
    申请号:FR1655733
    申请日:2016-06-20
    公开日:2017-12-22
    发明作者:Adrien Vincent；Jerome Sant；Marc Roubin
    申请人:Saint Gobain Centre de Recherche et dEtudes Europeen SAS；
    IPC主号:
    专利说明:

    Tableau 1
    Les résultats regroupés dans le tableau 1 qui précèdent indiquent que les exemples 2 à 5 selon l'invention présentent les meilleures performances combinées aux différents tests et mesures pratiquées.
    En particulier les filtres 2 à 5 dotés d'une membrane filtrante et en particulier d'une couche séparatrice membranaire selon l'invention présentent en particulier une résistance mécanique élevée (scratch test). En particulier le taux de rayures des couches selon l'invention reporté dans le tableau qui précède est comparable à celui obtenu lorsque le matériau de la membrane est constitué uniquement de Sic recristallisé obtenu à très haute température (voir exemple 6 comparatif). Au contraire, la couche séparatrice membranaire du filtre selon l'exemple comparatif 1, constituée d'un mélange d'alpha et de béta SiC selon un ratio massique α/β trop faible de 0,25, présente un taux de rayures très supérieur, propre à en faciliter l'arrachement et l'abrasion sous la pression du liquide.
    Si on se référé à la comparaison des exemples selon l'invention avec les exemples comparatifs let 6, on remarque qu'il devient possible par application de la présente invention de proposer des filtres très sélectifs, c'est-à-dire comprenant une membrane de filtration dont la taille médiane des pores est très fine, et dont l'étendue de la distribution en taille de pores est minimisée. Une telle propriété permet d'envisager l'utilisation de tels filtres jusque dans le domaine de l'ultrafiltration, c'est-à-dire pour la séparation de particules polluantes dans un liquide dont la taille médiane d50 est inférieure à 500 micromètres, notamment comprise entre 100 et 500 micromètres.
    En outre, on peut voir, à la lecture des résultats reportés dans le tableau 1, que les filtres selon les exemples 2 à 5 présentent comparativement non seulement un diamètre médian de pores d50 très faible, de l'ordre de 300 nm voire même de l'ordre de 100 nm, mais également une sélectivité très élevée, c'est-à-dire une capacité des filtres selon l'invention à limiter le risque de colmatage irréversible de la membrane.
    Au final, les résultats regroupés dans le tableau indiquent que le matériau utilisé selon l'invention pour fabriquer la couche séparatrice membranaire permet d'obtenir le meilleur compromis entre la résistance mécanique et des propriétés de porosité permettant de travailler dans le domaine de l'ultrafiltration. Le matériau constituant la membrane selon l'invention se caractérise en particulier par la présence d'une proportion importante, voire majoritaire de béta-SiC.
    FILTERS COMPRISING BETA-BASED SEPARATING LAYERS
    SIC The invention relates to the field of filtering structures made of an inorganic material, intended for the filtration of liquids, in particular structures coated with a membrane in order to separate particles or molecules from a liquid, more particularly from the water. The invention finds, for example, its application for the purification of production water resulting from oil extraction or shale gas. It is also used in various industrial processes for the purification or even separation of liquids in the field of chemistry, pharmaceuticals, food or agri-food.
    Filters have long been known using ceramic or non-ceramic membranes for filtering various fluids. These filters can operate according to the principle of frontal filtration, this technique involving the passage of the fluid to be treated through a filter medium, perpendicular to its surface. This technique is limited, in case of highly polluted waters, by the accumulation of particles and the formation of a cake on the surface of the filter media, and gives rise to a relatively rapid drop in permeate flow. On the other hand, this configuration allows the use of a simple system and with a lower energy consumption.
    According to another technique, tangential filtration is used, which, on the contrary, makes it possible to limit the accumulation of particles, thanks to the longitudinal circulation of the fluid on the surface of the membrane. The particles remain in the flow of circulation whereas the liquid can cross the membrane under the effect of the pressure. This technique provides stability of performance and filtration level.
    The strengths of the tangential filtration are its ease of implementation, its reliability through the use of organic membranes and / or inorganic porosity adapted to perform said filtration, and its continuous operation. In contrast, the tangential configuration ideally requires the use of at least two pumps, one pressurizing (or feeding) and the other recirculation. The recirculation pump often has a significant energy consumption.
    Tangential filtration uses little or no adjuvants and provides two separate fluids that can be both valuable, the concentrate (also called retentate) and the filtrate (also called permeate). It is a clean process that respects the environment. Tangential filtration techniques are particularly used for microfiltration, ultrafiltration, nanoflltratlon.
    Thus, many filter structures operating according to the principles of frontal or tangential filtration are known from the present technique.
    According to a configuration, a tangential filter may be configured so that the fluid to be treated initially passes through a porous wall, the permeate being collected by a collecting system which provides a seal and prevents contamination of the permeate by the fluid to be treated or the retentate.
    A configuration that responds to this mode is called FSM (for Fiat Sheet Membrane). Reference can be made to the publication available on the website: http: //www.liqtech.corn/img/user/file/FSM Sheet F 4 260 214V2.pdf. Another configuration may be a solid or hollow disk, fixed or mobile. Other configurations comprise or consist of tubular or parallelepipedal supports of a porous inorganic material formed of walls delimiting longitudinal channels parallel to the axis of said supports. The filtrate passes through the walls and is evacuated at the peripheral outer surface of the porous support in the case of tangential filtration or mainly at the outlet channels in the case of frontal filtration.
    The surface of said channels is also usually covered with at least one coating of a porous inorganic material, called a membrane, whose nature and morphology are adapted to stop molecules or particles whose size is close to or greater than the median pore diameter. of said membrane, when the filtered fluid is spread in the porosity of the porous support. The membrane is conventionally deposited on the inner surface of the support material by a process for coating a porous inorganic material with a slip followed by a consolidation heat treatment, in particular drying and optionally sintering of the ceramic membranes. The advantage of ceramic membranes, and more particularly silicon carbide membranes is their resistance to abrasion and corrosion. However, the method of manufacture and deposition of said membranes strongly impacts its properties and the realization of this type of membrane can be expensive and complex to master.
    Filters with silicon carbide membranes are known. For example, EP0219383A1 discloses a filter body whose membrane layer formed of SiC particles is directly calcined under nitrogen at a temperature of 1050 ° C or 1100 ° C. Given the particles and the sintering temperature employed, however, the abrasion resistance of the membrane is far too low.
    US Pat. No. 7,699,903 B2 describes membrane separation layers essentially made of recrystallized alpha-SiC except for unavoidable impurities. The process consists in preparing a mixture of two powders of very pure alpha-SiC particles with the exception of unavoidable impurities. This mixture is then shaped and then sintered between 1750 and 1950 ° C so as to obtain a crystallized SiC membrane filter in alpha form, or in "Sic alpha", with an interconnected porosity allowing, for a relatively low transmembrane pressure, to obtain a flow of filtered liquid several times greater than that of a filter, this time equipped with a ceramic membrane consisting of an oxide and having an equivalent pore diameter, especially between 0.1 and 0.8 microns.
    In industrial practice, however, it is extremely difficult to produce recrystallized SiC membranes with a very small median pore diameter, ie less than 0.8 microns, or even less than 500 nanometers or even less than 300. nanometers. Such an embodiment requires the use of extremely fine SiC powders, which pose problems of handling and packaging. In addition, the use of such fine powders entails considerable additional cost, since they can only be obtained by sophisticated and expensive selection and grinding processes.
    The pore size distribution of these industrially produced Sic alpha membranes, however, still remains too wide to access a domain such as ultrafiltration.
    Alternatively, the international application WO03 / 024892 has proposed a method for preparing a membrane support made from a mixture of Sic alpha particles, a silicon powder and a carbon precursor in order to obtain a porous body ( ie a support) formed essentially of Sic alpha grains.
    Moreover, many other publications indicate different configurations which aim at obtaining a filter presenting the optimal properties for the application and in particular: a low pressure drop, a highest and most homogeneous outgoing permeate flow possible; one channel to another in the cross-sectional plane of the filter; high mechanical strength and in particular high abrasion and resistance as measured by a scratch resistance test; high vis-a-vis selectivity; pollutant species to be filtered, ideally a high chemical resistance including acidity.
    In practice, the optimization of all or part of these parameters depends substantially on the properties of the membrane used as a separation layer in such filters and in particular its structural and mechanical characteristics.
    There is therefore a need for an abrasion-resistant and tear-off membrane which further has fine pores and as narrow a pore size distribution as possible in order to obtain a very selective filter.
    Such a membrane must also lead to a filter whose fouling (or "fouling") is low and whose flow recovery capacity after cleaning or backwashing is as high as possible.
    The work carried out by the applicant company has shown, according to another approach, that within such filtering structures, it was useful to act on the chemical composition of the membrane separator or membrane separator layer, to solve such a problem and improve further filtration performance of the structure, or even the life of the filter. The object of the present invention is more particularly to provide a filter incorporating a resistant filter membrane regardless of its conditions of use and whose longevity is thus improved, for identical or substantially improved filtration performance vis-à-vis -vis previous achievements.
    In particular, it has been demonstrated by the work of the applicant company, described below, a filter whose membrane has a high resistance to abrasion and tearing, and a small median pore diameter, adapted to its use for microfiltration, or preferably allowing a use for ultrafiltration, that is to say in particular comprising a membrane separator layer whose median pore diameter is less than or equal to 500 nanometers (nm), preferably less than 300 nm, while still retaining a very good selectivity. Such an objective could be achieved by an appropriate selection of the material constituting said layer, said material being able to be obtained by a method also object of the present invention. The invention thus relates in a first aspect to a filter for the filtration of a liquid, comprising or consisting of a support element made of a porous ceramic material and a membrane separating layer for the filtration of said liquid, said support element being covered on the part of its surface in contact with the liquid to be filtered by said membrane separating layer, said separating layer being made of a material comprising at least 70% by weight of SiC silicon carbide relative to the total weight of all the inorganic compounds present in said separating layer, said filter being characterized in that the ratio between the molar content of SiC in the beta form and the molar content of SiC in the alpha form (beta-SiC / alpha-SiC) is greater than 0.5, preferably greater than 0.7, more preferably greater than 1.0 and most preferably greater than 2.0.
    According to a possible mode, the part in contact with the liquid to be filtered is the outer surface of the filter and the membrane separating layer is advantageously deposited on this surface.
    According to another embodiment, said element has a tubular or parallelepipedal shape bounded by an external surface and comprising in its internal portion a set of adjacent channels, axes parallel to each other and separated from each other by walls of said porous ceramic material, at least a portion of said channels being covered on their inner surface with the membrane-separating layer and optionally at least a part of said outer surface is covered with the membrane-separating layer.
    According to another alternative mode, the element has a solid shape constituted by said porous ceramic material, said shape being straight or curved, for example a plate, said separating layer covering the outer surface of the element in contact with the liquid to be filtered.
    The total mass of all the inorganic compounds present in said separating layer corresponds very preferably to the mass of said separating layer.
    According to other optional and advantageous additional characteristics of the membrane-separating layer: the SiC represents more than 90%, preferably more than 95% or even more than 98% of the mass of the material constituting said separating layer. The content of Sic in its beta form in the separating layer is greater than 30%, greater than 50%, even greater than 70%, preferably greater than 75%, even greater than 80% or even greater than 95%. Said separating layer is made of a material comprising at least 25% by weight and more preferably at least 50% by weight of silicon carbide in the crystallographic form beta (β-SiC) relative to the sum of the inorganic compounds present in said layer. . The SiC constituting the grains of the separating layer is essentially, or even entirely, in beta crystallographic form. When SiC alpha is present, the ratio of the SiC beta content to the SiC alpha content in the membrane is less than 50, or even less than 20 and in particular between 0.5 and 50, preferably between 1, 0 and 20, even more preferably between 2 and 10. The porosity of the separating layer is between 10 and 70%, especially between 30 and 60%. - The mass oxygen content of the material constituting the separating layer is less than 1.0%, preferably less than 0.5%.
    The residual silicon content in the material constituting the separating layer is less than 1%, more preferably less than 0.5% by mass. Such a content leads indeed to a better chemical resistance of the layer. In order to avoid a too important residual silicon content, it is possible according to the invention to treat the sintered separating layer by annealing under nitrogen, typically between 1200 and 1500 ° C., while avoiding the oxidation of the membrane.
    The Al mass content of the material constituting the separating layer is less than 1.0%, more preferably less than 0.5%. - The nitrogen mass content (N) of the material constituting the separating layer is less than 1.0%, preferably less than 0.5%. - The mass content of Fe (Fe), expressed as Fe 2 O 3, of the material constituting the separating layer is between 0.01 and 2.0%, preferably between 0.1 and 1.0%. Such a content makes it possible to reduce the pore size dispersion of the separating layer after baking.
    The content of Bore (B), expressed in B2O3 form, of the material constituting the separating layer is between 0.01 and 1.5%, preferably between 0.05 and 1.0%. Such a content makes it possible to improve the resistance to corrosion of the membrane after cooking. The ceramic material constituting the separating layer comprises sintered SiC grains whose size distribution is between 20 nm and 10 microns.
    The membrane-separating layer comprises a binder phase comprising dense grains of beta-SiC of average size of between 20 nanometers and 5 microns. These dense SiC grains come from the initial carbon particles in the suspension before deposition on the porous monolithic support. These grains result from the reaction of these carbon particles with the molten silicon or in gaseous form, in particular in SiO 2 form, originating from the silicon particles introduced initially to the suspensioïi. They are scattered in the heat of the air and provide the essential cohesion of tnatriee. The binder phase cong> also preferably makes bumps of beta Sic of average size between 1 and 10 micrometers. These grains of SiC pecrèux provieiihèht presumably initial silicon particles in suspensioh avSnt deposit on the porous monolithic support. The inventor considers that these grains result from the reaction of these particles of silicon partially melted or gaseous soda, especially in SiO form, with the carbon particles initially introduced to the suspension. They are dispersed in the binder matrix and contribute to obtaining a maximum porosity of. Thus, the presence of these porous bepa Sic grains is particularly advantageous in reducing the loss of filler; while at the same time having the necessary selectivity of this separating layer; a granular fraction bound by the binder phase. This granular fracture preferably comprises particles of $ iC * in alphd or beta form, preferably crista: l..liS: ée under foime alpha, 't ^ iquemeht size between 0.5 and 50 micidmètres , whose median diameter of distribution is between 2 and 10 miCrottetrès. The median pore diameter of the separating layer is less than 500 nm and is preferably between 10 and 500 nanometers, especially between 50 and 500 nanometers, in particular between 100 and 500 nanometers. ·
    The diameter range of pore diameters is about 2: 3, the diameter of a pore population being the pore diameter of the separating layer for which the maximum volume of intrusion of, meecured on the pore distribution curve measured by pCfCsettetfie to the fIfure according to ISO 15901-1.2005 part 1, Dmin corresponding to the smallest pore diameter obtained by such a measurement under a mercury pressure of 2068 bar. Such a criterion is representative of the ability of the membrane to resist fouling and to be cleaned more easily by backwashing. It is considered that if this ratio is greater than 2/3, the membrane will tend to have a high rate of irreversible blockage, making it unusable or seriously limit its service life.
    The median diameter of pores can be considered as representative of the selectivity of the membrane: it will thus be possible to use the filter according to the invention in the fields of microfiltration or ultrafiltration as a function of this value of the median pore diameter.
    As regards the porous support, the following indications are given concerning preferred but non-limiting embodiments of the present invention: The porosity of the material constituting the porous support is between 20 and 70%, preferably between 30 and 60% . - The median pore diameter of the material constituting the porous support is between 5 and 50 microns, more preferably between 10 and 40 microns. - The porous support comprises and preferably consists of a ceramic material, preferably a non-oxide ceramic material, preferably selected from Si silicon carbide, in particular sintered Sic in liquid phase or solid phase, the recrystallized Si, silicon nitride, in particular SisN4, silicon oxynitride, in particular Si20N2, silicon and aluminum oxynitride, or a combination thereof. Preferably the support is made of silicon carbide, even more preferably of recrystallized SiC. The base of the tubular or parallelepipedal shape is polygonal, preferably square or hexagonal, or circular. The tubular or parallelepipedal shape has a central longitudinal axis of symmetry (A). - Especially in the case of a filter with frontal filtration, the channels are plugged at one end, preferably alternately, to define input channels and output channels so as to force the liquid entering through the channels of input to the surface of which is deposited the membrane through which the liquid passes before being discharged through the outlet channels.
    If the filter is tangential, the end of the tubular support may be in contact with a plate which is impervious to the liquid to be filtered and perforated at the place of the channels which face it so as to form a filter support placed in a tubing or a system filtration. Another possibility may be to introduce the tangential filter into the tubing a sealed peripheral seal at each end and around the filter so as to ensure the permeate flow independently of the concentrate flow. - The elements are of hexagonal section, the distance between two opposite sides of the hexagonal section being between 20 and 80 mm. - The ducts of the filter elements are open on both ends. - The conduits of the filter elements are alternately plugged on the insertion face of the liquid to be filtered and on the opposite side. - The ducts of the filter elements are open on the liquid introduction face and closed on the recovery face. A majority of the ducts, in particular more than 50% or even more than 80%, are of square, round or oblong section, preferably round, and more preferably have a hydraulic diameter of between 0.5 mm and 10 mm, preferably between 1mm and 5mm. The hydraulic diameter Dh of a channel is calculated, in a plane of any cross section P of the tubular structure, from the surface of the section of the channel S of said channel and its perimeter P, according to said section plane and by application of the following classic expression:
    Dh = 4 XS / P
    As indicated above, the filter according to the invention may comprise, in addition to the membrane separating layer, one or more primary layers disposed between the material constituting the support element and the material constituting the membrane. The role of this (these) layer (s) called (s) primary (s) is to facilitate the attachment of the separator layer and / or to prevent the particles of the separator layer pass through the support, especially when a deposit by coating.
    The filter may further comprise one or more primary layers disposed between the material constituting the support member and the material constituting the membrane separator layer.
    According to other advantageous but nonlimiting characteristics of this support layer: the average thickness of the membrane layers (separating and primary layer) is preferably between 1 μm and 150 μm, preferably between 10 μm and 100 μm, more preferably between 20 μm and 100 μm. pm and 80pm. the thickness ratio of the primary layer to that of the separating membrane layer is typically from 1 to 5, preferably from 1 to 2, the pore size of the primary layer is greater than that of the membrane separator layer typically a ratio 2 to 40 times higher, preferably 3 to 20 times higher.
    In the present description, unless otherwise specified, all percentages are by weight.
    The crystallized phases of alpha or beta SiC previously described and their respective proportions, in particular in the membrane-separating layer, can be determined by X-ray diffraction and Rietveld analysis.
    Classically, beta-SiC is understood to mean any phase corresponding to the crystallized polytype in the cubic form and in particular in the form 3C according to the Ramsdell notation.
    Similarly, the term alpha-SiC phase conventionally means any crystallized phase in the hexagonal or rhombohedral form and may be in different polytypes, most commonly 4H, 6H, 15R. The invention also relates to a membrane-separating layer as previously described, made of a material comprising more than 70% by weight of silicon carbide (SiC), said silicon carbide being at least partly present, especially for at least 25% by weight. % of the weight of the membrane separator layer, in the beta form and preferably for a major part, that is to say for at least 50% of the weight of the membrane separator layer, in beta form.
    Without the need to postpone them again here, it is obvious that the invention also relates to membranes meeting all the preferred characteristics described above, in relation to the filter structure in which said layer is incorporated.
    Finally, the invention relates to a method of manufacturing a membrane separating layer as previously described, in an element serving in particular for a tangential or frontal filter, preferably a tangential filter, comprising the following steps: preparation of a slurry to from a powder comprising a carbon source, in particular carbon particles and a silicon source preferably selected from metal silicon and silicon oxide, application of said slip on the support element, under conditions allowing the formation of a thin layer of said slip on the inner part of the channels of said filter, drying and then firing under a non-oxidizing atmosphere at a temperature of between 1350 ° C. and 1680 ° C., preferably between 1400 ° C. and 1650 ° C. C.
    The present invention thus also finds its particularity because of the method for the deposition and implementation of the membrane as described above. This can thus be obtained from a deposit of a suspension comprising precursors of SiC, that is to say leading to the synthesis of the SiC phase in beta form in the final layer, after firing at temperatures previously described.
    In particular, according to a method according to the invention, it is possible to deposit successively or concomitantly a precursor comprising the carbon element and a precursor comprising the silicon element. The layer (s) deposited (s) are then sintered (s) under a non-oxidizing atmosphere at a temperature below 1650 ° C, especially between 1350 and 1650 ° C.
    Preferably, the precursor of Si is a silicon metal powder having a median diameter of between 1 and 10 microns. Below 1 micrometer the powder of
    Slicium is very reactive and difficult to disperse in an aqueous suspension. Above 10 microns, the pore diameter generated in the membrane after firing is high and it is very difficult to maintain a separating layer having a median pore diameter of less than 500 nanometers.
    Preferably, the carbon precursor is a carbon powder having a median diameter of between 3 and 5 microns.
    If the sintering is carried out at a maximum temperature below the threshold of transformation or formation in Sic in its alpha form (1700 ° C.), it is nevertheless possible to envisage according to the invention additions of Sic particles in alpha form. in the suspension for the deposition of the membrane separator layer. The addition of SiC particles in alpha form makes it possible to reinforce the abrasion resistance of the separating layer.
    According to the inventor, however, the content of Sic alpha must preferably remain less than 25%, more preferably less than 20% or even less than 15%, or even less than 10% or even 5%, by weight and with respect to total mass of said separator layer after baking. Preferably, the alpha-SiC particles added, for at least 90% by weight of them, have a size of 0.1 micrometers, or even greater than 0.2 micrometers.
    In addition, the following indications are given:
    The open porosity and the median pore diameter of the porous support described in the present description are determined in known manner by mercury porosimetry, according to ISO 15901-1.2005 part 1.
    The porosity and the median pore diameter of the membrane layer, in particular the separating layer, are advantageously determined according to the invention by means of a scanning electron microscope. For example, sections of a wall of the support are made in cross-section, as illustrated in FIGS. 2 to 5 attached, so as to visualize the entire thickness of the coating over a cumulative length of at least 1.5. cm. The acquisition of the images is performed on a sample of at least 50 grains. The area and the equivalent diameter of each of the pores are obtained from the images by conventional image analysis techniques, possibly after a binarization of the image to increase the contrast. A distribution of equivalent diameters is thus deduced, from which the median diameter of pores is extracted. Similarly, this method can be used to determine a median size of the particles constituting the membrane layer.
    An example of determination of the median pore diameter or the median size of the particles constituting the separating layer, as an illustration, comprises the succession of the following steps, conventional in the field:
    A series of SEM images is taken from the support with its observed membrane layer in a cross-section (i.e. throughout the thickness of a wall). For more clarity, the pictures are taken on a polished section of the material. The acquisition of the image is performed over a cumulative length of the membrane layer at least equal to 1.5 cm, in order to obtain values representative of the entire sample.
    The images are preferably subjected to binarization techniques, well known in image processing techniques, to increase the contrast of the particle or pore contour.
    For each particle or each pore constituting the membrane layer, a measurement of its area is carried out. An equivalent diameter of pores or grain is determined, corresponding to the diameter of a perfect disk of the same area as that measured for said particle or for said pore (this operation may possibly be carried out using software especially dedicated Visilog® marketed by Noesis). a size distribution of particles or grains or pore diameter is thus obtained according to a standard distribution curve and a median particle size and / or a median pore diameter constituting the membrane layer are thus determined, this median size or median diameter respectively corresponding to the equivalent diameter dividing said distribution into a first population comprising only particles or pores of equivalent diameter greater than or equal to this median size and a second population comprising particles of equivalent diameter less than this median size or this median diameter.
    For the purposes of the present description and unless otherwise indicated, the median particle size or the median pore diameter measured by microscopy refers respectively to the diameter dso of the particles or pores below which 50% by number of the population is found.
    On the other hand, with regard to the pore diameter measured on the support by mercury porosimetry, the median diameter corresponds to a threshold of 50% of the population by volume.
    The term "sintering" is conventionally used in the field of ceramics (that is to say in the sense indicated in International Standard ISO 836: 2001, item 120), a consolidation by thermal treatment of a granular agglomerate. The heat treatment of the particles used as starting charge for obtaining the membrane layers according to the invention thus allows the junction and the development of their contact interfaces by movement of the atoms inside and between said particles.
    The sintering between the carbon grains and the metallic silicon grains according to the invention is normally essentially carried out in the liquid phase, the sintering temperature being greater than or close to the melting point of the metallic silicon.
    The sintering can be carried out in the presence of a sintering additive, such as an iron oxide. By sinter additive is meant a compound usually known to allow and / or accelerate the kinetics of the sintering reaction.
    The median diameter D50 of the particle powders used to produce the support or the layer or layers of the membrane is conventionally given by particle size distribution characterization, for example by means of a laser granulometer.
    The nitrogen and oxygen elemental mass contents of the separating layer can be determined after melting under an inert gas, for example by means of an analyzer marketed under the reference TC-436 by LECO Corporation.
    The SiC content can also be measured according to a protocol defined according to the ANSI standard B74.15-1992- (R2007) by difference between total carbon and free carbon, this difference corresponding to the carbon fixed in the form of silicon carbide.
    The residual metal silicon is measured according to the method known to those skilled in the art and referenced in ANSI B74-151992 (R2000).
    The nature and the content of the various mineral materials constituting the membrane are conventionally determined by ray diffraction and Rietveld analysis, according to techniques well known in the art. In particular, the various forms of silicon carbide, more particularly the level of beta-SiC in the membrane-separating layer, can be determined by this method.
    The following is a nonlimiting example for the realization of a filter according to the invention, of course also not limiting methods for obtaining such a filter and the method according to the present invention:
    In a first step, the filter support is obtained by extrusion of a paste through a die configured according to the geometry of the structure to be produced according to the invention. The extrusion is followed by drying and firing to sinter the inorganic material constituting the support and to obtain the characteristics of porosity and mechanical strength necessary for the application.
    For example, in the case of a SiC support, it may in particular be obtained according to the following manufacturing steps: - mixing of a mixture comprising particles of silicon carbide with a purity greater than 98% and presenting a particle size such that 75% by weight of the particles has a diameter greater than 30 microns, the median diameter by mass of this particle size fraction (measured by laser granulometer) being less than 300 microns. The mixture also comprises an organic binder of the cellulose derivative type. Water is added and kneaded to obtain a homogeneous paste whose plasticity allows extrusion, the die being configured to obtain the monoliths according to the invention. drying the green monoliths by microwave for a time sufficient to bring the water content not chemically bound to less than 1% by weight. baking up to a temperature of at least 1300 ° C in the case of a liquid-phase sintered Sic-based filter medium, silicon nitride, silicon oxynitride, silicon oxynitride and aluminum, or same BN and at least 1900 ° C and less than 2400 ° C in the case of a filter support based on recrystallized Sic sintered or solid phase. In the case of a nitride or oxynitride filter medium, the baking atmosphere is preferably nitrogenous. In the case of a recrystallized Sic filter medium, the baking atmosphere is preferably neutral and more particularly argon. The temperature is typically maintained for at least 1 hour and preferably for at least 3 hours. The obtained material has an open porosity of 20 to 60% by volume and a median pore diameter of about 5 to 50 microns.
    The filter support is then coated according to the invention with a membrane. One or more layers may be deposited in order to form a membrane according to various techniques known to those skilled in the art: deposition techniques from suspensions or slips, chemical vapor deposition (CVD) or thermal spraying techniques, by example plasma projection (plasma spraying).
    Preferably the layer or layers constituting the membrane are deposited by coating from slips or suspensions. A first layer (called primary or primary layer) is preferably first deposited in contact with the porous material constituting the substrate, acting as a bonding layer.
    Although preferentially present, in certain filter configurations, this primary layer may be absent, without departing from the scope of the invention.
    In order to control the rheology of the slips used for deposition of the successive layers (primary and membrane separating layer) and to respect an adequate viscosity (typically between 0.01 to 1.5 Pa.s, preferably 0.1 to 0.8 Pa. s under a shear rate of ls "^ measured at 22 ° C according to the standard DINC33-53019), thickening agents (in proportions typically between 0.02 and 2% of the body of water). Binding agents (typically between 0.5 and 20% of the SiC powder mass), dispersing agents (between 0.01 and 1% of the SiC powder mass) can also be added. The thickening agents are preferably cellulosic derivatives, the binding agents preferably PVA or acrylic derivatives and the dispersing agents are preferably of the ammonium polymethacrylate type.
    Organic additions expressed by weight of the slurry, in particular Dolapix A88 as a deflocculating agent, for example in a proportion of 0.01 to 0.5%, of Tylose, for example of the MH4000P type, as a thickener in a proportion of 0.01 to 1%, PVA as a tackifier at a rate of 0.1 to 2%, expressed by mass of solids; monoethylen glycol as plasticizer and 95% ethanol as surface tension reducer, are more particularly suitable.
    If the filter is configured for tangential filtration application, it can be attached to a perforated plate at the channel openings in a sealed manner to be installed in a tubing or filtration system. The heat treatment used to fix the perforated plate to the filter support must be performed at a temperature below the decomposition temperature of the composite membrane.
    According to the invention, several modes are possible in the process of depositing and baking a membrane according to the invention:
    According to a first embodiment, the preferably sintered filter medium is coated with an alpha-SiC or beta-SiC primer or a mixture of the two forms. The support provided with the layer is then sintered at high temperature.
    It is then deposited on the primer a suspension comprising the precursors of Si and C described above in order to form the membrane separator layer. The support thus coated is then sintered under a non-oxidizing atmosphere at a temperature of between 1350 and 1680 ° C. As indicated above, the silicon precursor may be fumed silica or silicone or its derivatives [or preferably a metal silicon powder and the carbon source is preferably a graphite or amorphous carbon powder.
    According to a second embodiment, the procedure is the same as for the first mode, but the primer layer is sintered at the same time as the separating layer. According to a third embodiment, the precursors are deposited separately in two successive layers.
    If the filter has alternately clogged channels in order to obtain a membrane filter operating according to the principles of the frontal filtration and if the clogging is performed after the deposition of the membrane at least for one face of the filter, or on the side of the channels of either on the outlet side, the plugging can be carried out with an SiC slip, the plugs being sintered at a temperature below the decomposition temperature of the composite membrane, preferably at the same time as the membrane.
    The figures associated with the following examples are provided to illustrate the invention and its advantages, without of course that the embodiments thus described can be considered as limiting the present invention.
    In the attached figures: FIG. 1 illustrates a conventional configuration of a tubular filter according to the current technique, according to a transverse sectional plane P. FIG. 2 is a microscopy plate of the membrane essentially in alpha Sic (FIG. a-SiC) according to Comparative Example 1. FIG. 3 is a microscopy view of the membrane essentially made of beta Sic (b-SiC) according to example 2 according to the invention. FIG. 4 is an electron micrograph of the filter according to example 4, showing the support, the primer and the membrane. - Figure 5 is another microscope slide according to Example 4 according to the invention, centered and enlarged on the membrane separator layer in beta Sic.
    Figure 1 illustrates a tangential filter 1 according to the current technique and according to the present invention, as used for the filtration of a fluid such as a liquid. FIG. 1 represents a schematic view of the transverse cross-section plane P. The filter comprises or most often consists of a support element 1 made of a porous inorganic material that is preferably non-oxide. The element conventionally has a tubular shape of longitudinal central axis A, delimited by an external surface 2. It comprises in its inner portion 3 a set of adjacent channels 4, axes parallel to each other and separated from each other by 8. The walls are made of a porous inorganic material passing the filtrate from the inner part 3 to the outer surface 2. The channels 4 are covered on their inner surface with a membrane 5 deposited on a primer, such as illustrated by the electron microscopy picture shown in Figure 1. This membrane 5 comes into contact with said fluid flowing in said channels and allows filtration.
    FIG. 4 shows an electron microscopy photograph taken on a channel 4 of FIG. 1, on the filter of example 4 which follows. This figure shows the porous support 100 of greater particle size, the primer layer 102, of intermediate granulometry, allowing the attachment of the membrane separator layer 103 of fine particle size.
    The following examples are for illustrative purposes only. They are not limiting and allow to better understand the technical advantages related to the implementation of the present invention:
    The supports according to all the examples are identical and are obtained according to the same experimental protocol which follows:
    3000 g of a mixture of the two powders of silicon carbide particles with a purity greater than 98% in the following proportions are mixed in a kneader: 75% by weight of a first particle powder having a median diameter of order of 60 micrometers and 25% by weight of a second particle powder having a median diameter of the order of 2 micrometers. (For the purposes of this description, the median diameter dso denotes the diameter of the particles below which 50% by weight of the population of said particles). 300 g of an organic binder of the cellulose derivative type.
    About 20% by weight of water is added relative to the total weight of SIC and of organic additive and kneaded to obtain a homogeneous paste whose plasticity allows the extrusion of a tubular structure, the die being configured to obtain monolithic blocks whose channels and outer walls have a structure according to the desired configuration and as shown in Figures 1 to 2 attached.
    More specifically, the fired monoliths have round channels of 2mm hydraulic diameter, the peripheral half-moon channels shown in the figures having a hydraulic diameter of 1.25mm. The average thickness of the outer wall is 1.1 mm and the OFA (Open Front Area) of the inlet face of the filter is 37%. The open front area (OFA) is obtained by calculating the ratio of the area covered by the sum of the cross sections of the channels to the total area of the corresponding cross-section of the channel. porous support.
    For each configuration, raw supports of 25 mm in diameter and 30 cm in length are synthesized.
    The green monoliths thus obtained are dried by microwave for a time sufficient to bring the water content not chemically bound to less than 1% by weight.
    The monoliths are then fired to a temperature of at least 2100 ° C which is maintained for 5 hours. The obtained material has an open porosity of 43% and a mean pore distribution diameter of about 25 microns, as measured by mercury porosimetry.
    Example 1 (comparative);
    According to this example, a silicon carbide membrane is deposited on the inner wall of the channels of a support structure as obtained previously, according to the method described below:
    A primer of attachment of the membrane consists initially of a slip whose mineral formulation comprises 48% by weight of a black Sic grain powder (SIKA DPF-C) whose median diameter D50 is about 10 micrometers, 32% by weight of a black Sic grain powder (SIKA FCP-07) whose median diameter D50 is about 2 micrometers, 13% by weight of a silicon grain powder metal whose median diameter D50 is about 4 micrometers, 7% of an amorphous carbon powder whose median diameter D50 is about 1 micrometer. The mixture is mixed in a deionized water solution, the amount of water representing approximately 50% of the total mass of the mixture.
    A slip of the material constituting the membrane separating layer is also prepared to be deposited on the primer, whose formulation comprises 80% by weight of alpha-SiC grains whose dso is of the order of 0.5 micrometer, 13% by weight of a metal silicon grain powder whose median diameter D50 is about 4 microns, 7% of an amorphous carbon powder whose median diameter D50 is about 1 micrometer. The mixture is mixed in a deionized water solution, the amount of water representing approximately 50% of the total mass of the mixture.
    The rheology of the slips was adjusted by adding organic additives at 0.5-0.7 Pa.s under a shear gradient of Is measured at 22 ° C. according to the DINC33-53019 standard.
    These two layers are deposited successively according to the same method described below: the slip is introduced into a tank with stirring (20 rpm). After a light vacuum de-aerating phase (typically 25 millibars) while maintaining stirring, the tank is pressurized approximately 0.7 bar in order to coat the interior of the support from its lower part until at its upper end. This operation takes only a few seconds for a support of 30 cm in length. Immediately after coating the slip on the inner wall of the support channels, the excess is removed by gravity.
    After the deposition of each layer, the supports are dried at ambient temperature for 10 minutes and then at 60 ° C. for 12 hours.
    Finally, after deposition of the layers and drying, the supports are baked under argon at a temperature of 1470 ° C. for 4 hours at ambient pressure.
    A cross section is performed on the filters thus obtained. The structure of the membrane is observed and studied under a scanning electron microscope. FIG. 2 shows the photograph obtained for the cross-section of the membrane. In this photograph, alpha-SiC grains predominate by weight and surrounded by very fine particles of beta-SiC.
    Example 2 (according to the invention);
    According to this example, the same procedure is carried out in Comparative Example 1 (identical and identical primary support) but the separating layer is obtained from a slip whose mineral composition is as follows: 20% by weight of grains of the alpha-SiC powder whose dso is of the order of 0.5 micrometer, 53% by weight of the powder of metallic silicon grains whose median diameter D50 is about 4 micrometers, 27% of the carbon powder amorphous whose median diameter D50 is about 1 micrometer.
    As for Example 1, the two layers (primary then membrane) are deposited successively on the support.
    The dried supports as previously described are finally baked under Argon at a temperature of 1470 ° C. for 4 hours at ambient pressure.
    FIG. 3 shows the photograph obtained for the cross-section of the membrane. We can see in this picture grains of alpha-SiC minority in weight and surrounded by very fine particles of beta-SiC, in this quantity the majority.
    Example 3 (according to the invention);
    According to this example, the procedure is identical to Example 2 but the separating layer is obtained from a slip whose mineral composition is as follows: 67% by weight of the powder of metallic silicon grains whose median diameter D50 is about 4 micrometers, 33% of the amorphous carbon powder whose median diameter D50 is about 1 micrometer. As for the previous examples, the two layers (primary and then separator) are successively deposited in the support.
    The dried supports as previously described are finally baked under argon at a temperature of 1470 ° C. for 4 hours at ambient pressure.
    Example 4 (according to the invention):
    According to this example, the same procedure as in Example 3 above is carried out, but the dried supports are finally baked under Argon at a higher temperature of 1600 ° C. for 4 hours at ambient pressure.
    FIG. 4 shows an electron microscopy of the filter according to this example, showing the support 100, the primary 102 and the separating layer 103 as previously described.
    FIG. 5 shows another photograph obtained for an enlarged section centered on the separating layer 103. Beta-SiC grains of different sizes, and in particular larger sized grains from the reaction of the metallic silicon grains by the carbon, these large grains being separated by grains of much smaller size resulting from the transformation of the carbon grains initially added to the suspension and forming a binder phase around said grains of larger cut.
    Example 5 (comparative):
    According to this example, the same procedure as in Example 3 above is carried out, but the dried supports are finally baked under argon at an even higher temperature of 1680 ° C. for 4 hours at ambient pressure. Such a temperature results in the conversion of a major part of beta-SiC to alpha-SiC.
    Example 6 (comparative):
    According to this example, the same procedure is carried out as in Example 1 above, but only a mineral part consisting of an initial alpha-SiC powder whose dso is of the order of 1 micrometer is used for making the slip. The dried supports are finally baked under Argon at a temperature of 1800 ° C. for 4 hours at ambient pressure.
    The properties and characteristics of the filters thus obtained are measured as follows:
    On the basis of the electron microscopy photographs, the average thickness of the successive layers obtained for each example is measured by image analysis. The average thickness of the primer is of the order of 30 microns and that of the membrane separator layer of the order of 30 microns for all the examples. The median pore diameter of the membrane layer varies between 100 and 1100 nm according to the examples, as shown in Table 1 which follows.
    In the following table:
    The overall porosity of the membrane, in percent, and the diameter and D50 of the pores in the separating membrane were determined by observation of images taken under a scanning microscope as previously described.
    In order to determine the selectivity criterion (Dpic-Dmin) / Dpic a pore size curve was obtained by mercury porosimetry.
    The pore volume (Vi) was measured by mercury intrusion at 2000 bar using an Autopore IV 9500 Micromeritics mercury porosimeter, on a sample of 1 cm3 approximately. The applicable standard is ISO I590I-I.2005 part 1. The increase in pressure up to high pressure leads to "push" the mercury into pores of smaller and smaller size. The intrusion of mercury is conventionally done in two stages. Initially, a mercury intrusion is made at low pressure up to 44 psia (about 3 bar), using air pressure to introduce mercury into the larger pores (> 4pm).
    In a second step, a high-pressure intrusion is carried out with oil up to the maximum pressure of 30000 psia (2068 bar). It was possible to determine the pore diameter Dpic of the separating layer for which the volume of mercury is maximum. Similarly it was determined Dmin corresponding to the smallest pore diameter obtained by mercury intrusion.
    The composition of the membrane after firing, including the respective percentages of alpha and beta Sic, were determined as follows:
    The membrane pieces taken from the filter samples of the preceding examples were analyzed with the aid of the PANALALTIC X'Pert equipment in Kam configuration and rapid detection according to the following experimental parameters: -According: Rietveld analysis program -HighScore
    More »: from 5 ° to 80 ° in 2Θ, no 0.017 °, 150 s / step - Front optics: Fixed divergence slot: 1/4 °
    Slot of Soller 0.04 rad Mask: 10mm
    Fixed antidiffusion slot: 1/2 ° - Sample holder: Spinner (rotation of the sample on itself in order to increase the counting statistics and limit the preferential orientations) - Rear optics: Fixed antidiffusion slot: 1/4 °
    Slot of Soller: 0.04 rad Filter Ni
    The diffractograms were analyzed qualitatively with the EVA software and the PDF2-ICDD database (Release 2005) and then analyzed quantitatively with the HighScore Plus software according to a Rietveld refinement.
    The SiC content was measured according to ANSI B74.15-192- (R2007)
    The details of the other experimental protocols followed are additionally given below:
    Measurement of the scratch depth of the membrane separator layer, an essential factor of filter longevity, also called "scratch test", is carried out using a rockwell C conical spherical tip forming a conical angle of 120 °. , the radius of curvature of the tip being 200 microns. The tip is driven at a constant speed of 12mm / min according to an incremental load of IN in steps of 1 mm over a measuring length of 6mm. Several passages can be made. The degradation of the coating is a combination of elastic and / or plastic indentation stresses, frictional stresses and residual internal stresses within the coating material layer. The penetration depth of the indenter is measured after a sixth pass at 4N. The degree of scratch depth was measured as a percentage relative to the reference according to the invention (example 2) set at 100. The resistance ratio of the other examples is calculated by making the depth ratio of the indenter of the example divided by the depth of the indenter measured in Example 2. A rate greater than 100% represents a scratch resistance lower than the reference.
    The characteristics and the properties of the filters and of the membrane separating layer (indicated in the table below by membrane) obtained according to Examples 1 to 6 are given in Table 1 below:
    Table 1
    The results summarized in Table 1 above indicate that examples 2 to 5 according to the invention have the best performance combined with different tests and measurements.
    In particular the filters 2 to 5 with a filter membrane and in particular a membrane separator layer according to the invention have in particular a high mechanical strength (scratch test). In particular, the level of scratches of the layers according to the invention reported in the preceding table is comparable to that obtained when the material of the membrane consists solely of recrystallized Sic obtained at a very high temperature (see Comparative Example 6). On the other hand, the membrane-separating layer of the filter according to Comparative Example 1, consisting of a mixture of alpha and beta SiC in a mass ratio α / β that is too low of 0.25, has a much higher rate of scratches. clean to facilitate tearing and abrasion under the pressure of the liquid.
    Referring to the comparison of the examples according to the invention with Comparative Examples let 6, it is noted that it becomes possible by application of the present invention to provide very selective filters, that is to say comprising a membrane of filtration whose median pore size is very fine, and the extent of the pore size distribution is minimized. Such a property makes it possible to envisage the use of such filters in the field of ultrafiltration, that is to say for the separation of polluting particles in a liquid whose median size d50 is less than 500 micrometers, in particular between 100 and 500 micrometers.
    In addition, it can be seen from the results reported in Table 1 that the filters according to Examples 2 to 5 have comparatively not only a median pore diameter d50 which is very small, of the order of 300 nm or even the order of 100 nm, but also a very high selectivity, that is to say, a capacity of the filters according to the invention to limit the risk of irreversible clogging of the membrane.
    Finally, the results grouped together in the table indicate that the material used according to the invention to manufacture the membrane separator layer makes it possible to obtain the best compromise between the mechanical strength and the porosity properties making it possible to work in the ultrafiltration field. . The material constituting the membrane according to the invention is characterized in particular by the presence of a large proportion, or even a majority of beta-SiC.
    权利要求:
    Claims (16)
    [1" id="c-fr-0001]
    1. Filter for the filtration of a liquid, comprising or consisting of a support element made of a porous ceramic material and a membrane separating layer for the filtration of said liquid, said support element being covered on the part of its surface in contact with the liquid to be filtered by said membrane separating layer, said separating layer being made of a material comprising at least 70% by weight of silicon carb silicon relative to the total weight of all the inorganic compounds present in said separating layer, said filter being characterized in the ratio of the molar SiC content in the beta form to the molar content of SiC in the alpha form is greater than 0.5.
    [2" id="c-fr-0002]
    2. Filter according to the preceding claim characterized in that the ratio between the molar content of SiC in the beta form and the molar content of SiC in the alpha form is greater than 0.7, preferably greater than 1.0 and so preferred greater than 2.0.
    [3" id="c-fr-0003]
    3. Filter according to one of the preceding claims wherein said element having a tubular or parallelepiped shape defined by an outer surface and comprising in its inner portion a set of adjacent channels, axes parallel to each other and separated from each other by walls of said porous ceramic material, at least a portion of said channels being covered on their inner surface with the membrane separating layer and optionally at least a portion of said outer surface is recoviverte of the bridging separable layer,
    [4" id="c-fr-0004]
    4. Filter according to 1-a reemember 1 or 2 in which the element; having a solid fortoe constituted by said material cetattiidU'e pdrer® :, said form being straight or curved, garΟχΟχτ ^ ^ ür ür ür plate, said separating layer recoijidraht the surface of the element in contact with the liquid to be filtered.
    [5" id="c-fr-0005]
    5. Filter according to uhè previous revehdications, wherein said separating layer is made of a material comprising at least 90% by weight of silicon carbide based on the total weight of the inorganic compounds present in said separating layer.
    [6" id="c-fr-0006]
    6. The filter according to one of the preceding claims, wherein said separating layer is made of a material comprising at least 25% by weight of beta-silicon carbide; to the total weight of the inorganic compounds present in the said separating layer ,. 7. Pillow: according to one of the piécédhtés claims, wherein said separating layer is made in ^ a material comprising at least 50% by weight of silicon crebüre in the crystallographic form: beta relative to the total weight of Com |) 0sés Minerals present in said layer.
    [7" id="c-fr-0007]
    8. Filter according to the preceding claim 1lpha-SiC, wherein said ratio; Beta-Si / / alpha-Sic is less than 50, preferably less than 20. 9. The filter according to one of the preceding awakenings> wherein the mass content of silicon metal in the separating layer is less than 1% by weight. relative to the total weight of the inorganic compounds present in the separating layer.
    [8" id="c-fr-0008]
    10. Filter according to one of the preceding claims, wherein the ratio [dpic-dmin] / dpic pore diameters is less than 2/3, the dpic diameter of a pore population being the pore diameter of the layer. separator for which, on the pore distribution curve measured by mercury porosimetry is measured the maximum mercury intrusion volume, Dmin corresponding to the smallest pore diameter obtained by such a measurement, under a pressure of 2068 bar (3000 psi) and being measured according to ISO 15901-1.2005.
    [9" id="c-fr-0009]
    11. Filter according to one of the preceding claims, wherein the ceramic material of the membrane separator layer comprises sintered SiC grains with a size of 20 nm and 10 microns.
    [10" id="c-fr-0010]
    12. Filter according to one of the preceding claims, wherein the porosity of the separating layer is between 10 and 70%.
    [11" id="c-fr-0011]
    13. Filter according to one of the preceding claims, wherein the median pore diameter of the separator layer is between 10 nanometers and 500 nanometers.
    [12" id="c-fr-0012]
    14. The filter according to one of the preceding claims, wherein the median size of SiC grains in said material is between 20 nanometers and 10 micrometers.
    [13" id="c-fr-0013]
    15. The filter according to one of the preceding claims, wherein the elemental oxygen mass content of the material constituting the separating layer is less than or equal to 1% and preferably less than 0.5%.
    [14" id="c-fr-0014]
    16. Filter according to one of the preceding claims wherein the open porosity of the material constituting the support element is between 20 and 70%, the median pore diameter of the material constituting the porous support element being preferably between 5 and 70%. and 50 micrometers.
    [15" id="c-fr-0015]
    17. Filter according to one of the preceding claims further comprising one or more primary layers disposed between the material constituting the support element and the material constituting the membrane separator layer.
    [16" id="c-fr-0016]
    18. A method of manufacturing a membrane separator layer according to the preceding claim, in an element for a filter according to one of the preceding claims, comprising the following steps: - preparation of a slip from a powder comprising a source of carbon, in particular of carbon particles and of a silicon source preferably chosen from metallic silicon and silicon oxide, - application of said slip on the support element, under conditions allowing the formation of a layer thin of said slip on the inner part of the channels of said filter, drying and baking under a non-oxidizing atmosphere at a temperature between 1350 ° C and 1680 ° C, preferably between 1400 ° C and 1650 ° C.
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    同族专利:
    公开号 | 公开日
    EP3471863A1|2019-04-24|
    WO2017220907A1|2017-12-28|
    CN109310953A|2019-02-05|
    FR3052682B1|2020-11-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2003024892A1|2001-09-21|2003-03-27|Stobbe Tech Holding A/S|Porous ceramic structures and a preparing method|
    US7699903B2|2003-07-09|2010-04-20|Saint-Gobain Industrie Keramik Rödental GmbH|Porous ceramic body and method for production thereof|
    EP2559470A1|2010-04-12|2013-02-20|Sumitomo Osaka Cement Co., Ltd.|Exhaust gas purification filter, and method for manufacturing exhaust gas purification filter|
    US20160121272A1|2014-10-31|2016-05-05|Corning Incorporated|Inorganic membrane filter and methods thereof|WO2020109731A1|2018-11-30|2020-06-04|Saint-Gobain Centre De Recherches Et D'etudes Europeen|Dynamic filtering device with porous ceramic silicon carbide plate|
    WO2021009084A1|2019-07-18|2021-01-21|Saint-Gobain Centre De Recherches Et D'etudes Europeen|Filter comprising a silicone carbide separator layer|FR2587026B1|1985-09-09|1992-02-07|Centre Nat Rech Scient|USE OF SINTERABLE POWDERS OF PARTICULAR SIZE IN THE PRODUCTION OF FILTER ELEMENTS IN POROUS CERAMIC, AND CERAMICS THUS OBTAINED|
    US7867313B2|2005-07-05|2011-01-11|Helsa-Automotive Gmbh & Co. Kg|Porous β-SiC-containing ceramic molded article comprising an aluminum oxide coating, and method for the production thereof|
    EP1741687B1|2005-07-05|2011-10-12|MANN+HUMMEL Innenraumfilter GmbH & Co. KG|Porous ß-SiC containing shaped ceramic body and method of making it.|
    CN1793040A|2006-01-13|2006-06-28|清华大学|Porous ceramic support for high strength inorganic separating film and preparation process thereof|
    KR100913786B1|2007-08-13|2009-08-26|한국세라믹기술원|Silicon carbide membrane, method for producing it and hydrogen separation membrane for high temperature using it|CN111874866B|2020-07-03|2021-10-15|湖南大学|Porous ceramic and preparation method and application thereof|
    法律状态:
    2017-06-23| PLFP| Fee payment|Year of fee payment: 2 |
    2017-12-22| PLSC| Search report ready|Effective date: 20171222 |
    2018-06-25| PLFP| Fee payment|Year of fee payment: 3 |
    2020-06-29| PLFP| Fee payment|Year of fee payment: 5 |
    2021-06-30| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1655733A|FR3052682B1|2016-06-20|2016-06-20|FILTERS INCLUDING SEPARATING LAYERS BASED ON BETA-SIC|FR1655733A| FR3052682B1|2016-06-20|2016-06-20|FILTERS INCLUDING SEPARATING LAYERS BASED ON BETA-SIC|
    PCT/FR2017/051600| WO2017220907A1|2016-06-20|2017-06-19|Filters comprising beta-sic-based separation layers|
    EP17740055.3A| EP3471863A1|2016-06-20|2017-06-19|Filters comprising beta-sic-based separation layers|
    CN201780038313.8A| CN109310953A|2016-06-20|2017-06-19|Filter comprising the separating layer based on β-SIC|
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