Catalyst supports containing hollow microspheres

Abstract

The present invention relates to a calcined medium, in particular a catalyst or catalytic medium or adsorbent / absorbent mass, in particular in the form of extrudates, pellets, granules or beads, comprising a microporous matrix, the medium comprising carbonates, clays, zeolites, oxides or metals and / or silicon hydroxides, the matrix incorporating hollow mineral microspheres of different compositions in a content of 0.3 to 50% by weight, in particular 0.5 to 15% by weight, based on the weight of the matrix.

Description

[Technical Field]

[0001] The present invention relates to supports, catalyst type supports, catalyst supports or also absorbent masses or capture mass type adsorbent masses, which are used in the petroleum and petrochemical industry, including natural gas, or also in the field of biomass conversion. The invention also relates to their mode of production and all their uses. [Background technology]

[0002] In known processes, catalysts normally employed for the synthesis, conversion or processing of hydrocarbons, natural gas or petrochemical intermediates consist of a support on which is optionally deposited one or more compounds selected in particular from metal oxides, such as oxides of cobalt, nickel, molybdenum, iron, ruthenium etc., heteropolyanions, or noble metals, such as palladium, platinum, rhodium etc. The deposited compounds constitute the active phase of the catalyst after an optional sulfiding and / or reduction step.

[0003] The support, whether intended to be impregnated with such an active phase or not, is generally based on porous oxides (alumina, silica, titanium oxide, magnesia), clays and mixtures of at least two of these materials. The support is chosen to exhibit a porosity profile / distribution appropriate to the type of reaction to be carried out. It may be shaped in the form of beads, pellets, granules or especially extrudates (reference will be made later to "grain" to define them generally, and this term will be retained for the granules once provided with the catalytically active phase for the sake of brevity).

[0004] The reasoning is generally based on the weight of catalyst to fill a given reactor volume. It is generally sought to reduce the weight of the catalyst support, since a lighter support allows for a lower weight of catalyst to be loaded into a given reactor volume, which is advantageous in several ways (economically as well as for industrial implementation, less weight to be loaded into the reactor, and for the life of the support, less crushing of the support loaded at the bottom, for example, in a fixed catalyst bed).

[0005] In fact, the density of a support depends on its morphology: both external (i.e., due to the shape and size of the granules) and internal (due to its pore volume). If the internal morphology of the granules is changed, the weight of the catalyst support can be reduced by increasing its pore volume. In doing so, the number and / or size of the pores, i.e., the pore volume of the granules, is generally increased, which has a negative impact on the mechanical strength of the granules and tends to weaken them. However, mechanical strength is an important property of granules, especially since it determines their resistance to crushing and also to friction phenomena, for example, when the support forms part of a moving bed. Furthermore, modifying the porosity texture (pore volume, pore distribution) can have an undesirable impact on catalyst performance, especially since this modification of porosity can lead to modifications in the diffusion of reactants and products of the reactions occurring in a given reactor, together with possible modifications of the access of the reactants to the active sites of the support.

[0006] Therefore, it is a challenge to reconcile the need for weight reduction, the need for mechanical strength and preserving the performance qualities of the catalyst.

[0007] According to a first solution for reducing the weight of granules, it is known to add "pore-forming" compounds during the mixing of the various compounds or compound precursors of the support, followed by shaping and calcination: these pore-forming agents burn off / disappear during the calcination and therefore create the desired porosity in the granules once calcined, in particular additional porosity, which makes it possible to reduce the weight of the support. Reference may be made, for example, to Patent Document 1, which relates to catalysts for catalytic reforming starting from an alumina support, and which describes the use of pore-forming agents, in particular solid pore-forming agents of the starch type or liquid pore-forming agents of the oil type, added during the preparation of the spherical alumina particles before their calcination.

[0008] According to an alternative form described in US Pat. No. 5,999,149, during the preparation of the catalyst support in the form of alumina or aluminosilicate beads, hollow glass spheres, the diameter of which is between 50 and 175 micrometers and which act as pore formers, are added: the hollow spheres create porosity in the beads by dissolving during the final calcination.

[0009] Furthermore, catalyst supports based on porous hollow microspheres are known from US Pat. No. 5,629,999: here, hollow microspheres constitute the support and are intended to be impregnated with a catalytically active phase, which at least partly fills the central cavity of the microspheres.

[0010] The object of the present invention is therefore to improve supports as defined above. The invention is aimed in particular at reducing their weight whilst maintaining their mechanical properties. The invention is even more particularly aimed at maintaining the pore distribution of the support, and in particular the catalytic performance qualities of the support once the catalytic phase has been added. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] European Patent Application Publication No. 3090986 [Patent Document 2] U.S. Patent No. 4,292,206 [Patent Document 3] U.S. Patent No. 4,637,990 Summary of the Invention [Means for solving the problem]

[0012] (Summary of the Invention) The subject of the present invention is first of all a calcined support, in particular in the form of extrudates, pellets, granules or beads, which comprises a porous matrix based on metal carbonates, clays, zeolites, oxides or hydroxides and / or silicon, which matrix incorporates hollow inorganic microspheres of different composition in a content of 0.3% to 50% by weight, in particular 0.5% to 20% by weight, based on the weight of the matrix.

[0013] Weight content of microspheres should be understood by considering dry matter content throughout this specification.

[0014] Advantageously, the maximum content of hollow microspheres is chosen so as to make it possible to maintain the catalytic and mechanical performance qualities of the support obtained.

[0015] Preferably, the content is less than or equal to 15% by weight, in particular between 0.5% and 10% by weight of the matrix, more particularly between 0.5% and 4.5% by weight, even more particularly between 1% and 4.5% by weight or between 1% and 4% by weight of the matrix.

[0016] According to the present invention, the term "support" is understood to mean a support which exhibits catalytic properties itself, or a catalyst support intended to receive a catalytically active phase, the resulting catalyst being able to have variable properties between the support and the active phase, or alternatively an adsorbent or absorbent mass, used in the petroleum or petrochemical industry, in particular for the processing or conversion of hydrocarbons, petroleum or also natural gas (but also for the processing or conversion of biomass to give clean fuels), and also for the production and refining of key petrochemical intermediates.

[0017] This is because it has been found that calcined supports containing this content of hollow microspheres are lighter than similar supports lacking such hollow microspheres, due to the closed porosity they impart to the support. Unlike previous uses of hollow microspheres, here, according to the present invention, the microspheres are incorporated into the calcined support, where they still exhibit their closed cavities, which were not destroyed during the preparation of the support. Furthermore, neither will they replace the porous matrix with respect to the active catalytic phase: their cavities remain closed and inaccessible to the active phase. Moreover, as will be seen below, their outer walls lack sufficient porosity for the active phase to be deposited thereon or are significantly impregnated on their surface.

[0018] The presence of these hollow microspheres confers a reduced density on the carrier of the present invention, but does not substantially alter the pore distribution of the matrix itself. The inventors can also show that the mechanical strength of the carrier is not adversely affected to a significant extent by these microspheres, and that catalysts using the carrier according to the present invention likewise exhibit similar characteristics and performance qualities. It should be noted that it is the choice of the content of microspheres in the matrix provided by the present invention that makes it possible to combine weight reduction and preservation of mechanical properties. This is because everything happens as if these hollow microspheres had been incorporated into the carrier, without affecting the properties of the carrier apart from, inter alia, its reduced density.

[0019] Preferably, according to the invention, the content of hollow microspheres is at most 15% by weight of the matrix, in particular at least 1% by weight, in particular 0.5% to 20% by weight or 1.5% to 5% by weight. Preferably, the content is 0.5% to 4.5% by weight of the matrix, and even more particularly 1% to 45% by weight or 1% to 4% by weight of the matrix.

[0020] This minimum content makes it possible to obtain a weight reduction significant enough to be truly advantageous on an industrial scale. The maximum content ensures the preservation of the cohesion of the support and its mechanical properties. Furthermore, the proposed maximum content minimizes the modification of the pore texture (pore volume, pore distribution) compared to an identical support but without microspheres. Therefore, the catalytic performance of catalysts based on the calcined support according to the invention or on the support used directly as catalyst or adsorbent is maintained.

[0021] Advantageously, the ratio of the smallest dimension of the pellets or granules or extrudates or beads to the (external) diameter of the hollow microspheres is at least 5 / 1, in particular at least 8 / 1, in particular at least 20 / 1, and in some cases can range from at least 100 / 1 to at most 2000 / 1. The support granules therefore preferably have dimensions larger than those of the hollow microspheres, which ensures preservation of the properties of the support with microspheres compared to a support without microspheres.

[0022] As a non-limiting example, use may be made of microspheres in the form of aluminosilicate cenospheres (phyllites) having a diameter of 100 micrometers, with a matrix to produce granules, in particular extrudates, having a diameter of 1.6 mm. For granules of the same size, it is also possible to use hollow glass microspheres having a diameter of 20 micrometers.

[0023] Preferably, the hollow microspheres have a median diameter D 50is 150 micrometers or less, particularly 110 micrometers or less, 100 micrometers or less, 80 micrometers or less, or 50 micrometers or less, and preferably at least 1 micrometer, or at least 5 micrometers, or at least 10 micrometers. These ranges are selected to withstand extrusion while sufficiently lightweighting the resulting support and ensuring the preservation of the properties of the support with microspheres compared to a support without microspheres.

[0024] Preferably, the smallest dimension of the carrier of the pellet, granule or bead or granule type is at least 0.3 mm, in particular 0.5 to 6 mm.

[0025] Preferably, the wall thickness of the hollow microspheres is at least 5% of their diameter, in particular at least 10% of said diameter. A sufficient thickness of their wall makes them sufficiently mechanically resistant, while their density is low enough to allow targeted weight reduction.

[0026] Advantageously, the carrier according to the invention exhibits a porous texture similar to that of a carrier lacking hollow microspheres.

[0027] Preferably, the absolute density of the hollow microspheres is 0.1 to 1.3 g / cm 3 , especially 0.25 to 0.85 g / cm 3 Therefore, even a low content of hollow microspheres in the carrier allows for a significant reduction in the density of the carrier in view of their low absolute density.

[0028] Preferably, the melting point of the microspheres is at least 500° C., in particular at least 600° C., in particular at least 800° C. or at least 1000° C., and preferably at most 1500° C., in particular at most 1450° C. Due to these high melting points, their integrity can be preserved during calcination of the support into which they are incorporated. Conventional calcination temperatures for catalyst supports are generally below these values.

[0029] Advantageously, the wall of the hollow microspheres is not porous, i.e., it is continuous and lacks porosity: the active catalytic phase would not want to be deposited there and would not be able to impregnate these smooth walls (this term must be understood in comparison with the rest of the support, for some of which it is porous and has porous / rough walls).

[0030] According to one embodiment, the gas contained inside the hollow microspheres is nitrogen or CO2 or any gas, inert or not, and in particular, sulfur-based.

[0031] The hollow microspheres are made, for example, from borosilicate glass type glass or from ceramic, since this type of material presents many advantages within the scope of the present invention: it is largely chemically inert and it can withstand very high temperatures without melting, which means that it can withstand normal firing temperatures without deterioration (thus preserving its closed porosity).

[0032] Advantageously, the oxides or hydroxides of the metals of the matrix are chosen from at least one of the following compounds: carbonates / oxides / hydroxides of titanium, aluminum, copper, zirconium, zinc or silicon, alone or in mixtures.

[0033] Preferably, the support according to the invention is chosen from alumina, silica, titanium dioxide, zeolites, copper oxide, zirconium oxide and metal oxides or mixtures of at least two of these materials, and may involve carbonate(s) or clay(s).

[0034] Advantageously, the calcined support according to the invention comprises a porous matrix consisting essentially of a zeolite or an oxide or hydroxide of aluminium and / or silicon or titanium oxide, alone or in admixture, in particular a silica-alumina mixture.

[0035] Another subject of the invention is a catalyst comprising a support as defined above and at least one element or compound active for catalytic action (also called active phase), impregnated and / or deposited on the matrix, and chosen in particular from at least one element from groups VIIIB or IB or IIB, and in particular from one of the following elements: cobalt, molybdenum, nickel, palladium, platinum, rhodium, ruthenium, iron or tin.

[0036] Another subject of the invention is the use of the above-mentioned supports as catalysts, since for certain types of processes the support itself can act as a catalyst. A non-limiting example therefore consists of a titanium-based support for the recovery of sulfur in hydrocarbon streams of the Claus process type.

[0037] Another subject of the invention is the use of the above carriers as adsorption / absorption masses, since for certain types of impurities the carriers themselves can act as adsorbents.

[0038] Another subject of the invention is the use of the catalysts described above as catalysts in processes for the synthesis, processing or conversion of hydrocarbons, natural gas, vegetable oils and / or biomass, in particular for hydrotreating, hydroconversion, selective hydrogenation, hydrocracking, reforming, isomerization, NOx treatment, selective catalytic reduction or dehydrocyclization.

[0039] Another subject of the invention is a method for the production by extrusion of the above-mentioned supports, which method comprises the steps of preparing a paste containing, on the one hand, hollow microspheres and, on the other hand, clay and / or zeolite or also metal or silicon carbonates / oxides and / or hydroxides, extruding said paste to give extrudates, drying the extrudates, calcining the extrudates at a temperature below the melting point of the hollow microspheres, and optionally (subsequent) a hydrothermal treatment.

[0040] Another subject of the invention is a process for the production of the above-mentioned supports by coagulation to give beads (a technique also known as the oil drop technique), which comprises the steps of preparing a liquid suspension containing, on the one hand, clays and / or zeolites or also metal and / or silicon carbonates / oxides and / or hydroxides, and, on the other hand, hollow microspheres, followed by a step of coagulation of said suspension to give beads, followed by a step of calcining the beads at a temperature below the melting point of the hollow microspheres, and an optional (subsequent) step of hydrothermal treatment.

[0041] Another subject of the invention is a method for producing the above-mentioned carriers by granulation, which method comprises the steps of preparing a paste containing, on the one hand, hollow microspheres and, on the other hand, clay and / or zeolite or also metal and / or silicon carbonates / oxides and / or hydroxides, granulating the paste to give granules, drying the granules, followed by calcining the granules at a temperature below the melting point of the hollow microspheres, and optionally (subsequent) a hydrothermal treatment.

[0042] Whatever the shaping of the support, it generally involves a calcination step, which is why the material of the microspheres is chosen so that it exhibits a melting point that is preferably at least 20° C., and in particular at least 50° C., higher than the calcination temperature of the pellets, extrudates, beads or granules: their integrity during calcination to preserve closed porosity is therefore guaranteed. DETAILED DESCRIPTION OF THE INVENTION

[0043] (Description of the embodiment) The invention will be described in detail below using non-limiting embodiments.

[0044] (definition) Throughout this specification: - the term "tapped bulk density" of powders, also written as "TBD", expressed in grams per millimeter (g / mL), is understood to mean the weight of the catalyst support that can be introduced into a unit volume; - the term "micropores" is understood to mean all pores having a diameter strictly less than 2 nm; the term "mesopores" is understood to mean all pores having a diameter between 2 and 50 nm; - the term "macropores" is understood to mean all pores having a diameter strictly greater than 50 nm; - the term "hollow microsphere" is understood to mean a particle of substantially spherical geometry with a diameter of the order of micrometers (1 μm to 1 mm), which is hollow and whose cavity / cavities are filled with gas; - The term "diameter of the hollow microspheres" refers to the volume median diameter D of the hollow microspheres. 50 is understood to mean; - the term "absolute density" is understood to mean the weight divided by the total volume of the sample minus the accessible (or open) pore volume, the accessible pore volume being measured by helium picometry; The term "volume median pore diameter Dp" refers to the pore volume V Hg is understood to mean a pore diameter of which half is in larger pores and the other half is in smaller pores, as measured by mercury intrusion porosimetry; - The term "mercury intrusion pore volume per grain volume V" Hg / V 粒体 " is the mercury intrusion pore volume V Hg (mL / g) multiplied by the granular density of this same material; - the term "monomodality" is understood to mean a characteristic that reflects the narrowness of the pore distribution and corresponds to the ratio of the pore volume of pores having a size between the volume median diameter plus or minus 15 Å to the pore volume of pores having a size between the volume median diameter plus or minus 30 Å, which is the pore volume at different pore diameters: (D 中位+15A Volume at -D 中位-15A (Volume at the location) / (D 中位+30A Volume at -D 中位-30A (Volume at It is calculated using

[0045] The textural and structural properties of the supports and catalysts described below are determined by characterization methods known to those skilled in the art. The total pore volume and pore distribution are determined in the present invention by mercury porosimetry (see Rouquerol F., Rouquerol J. and Singh K., "Adsorption by Powders & Porous Solids: Principles, Methodology and Applications", Academic Press, 1999). More specifically, the mercury intrusion pore volume V Hg is measured by mercury porosimetry according to standard ASTM D4284-12, for example with a Micromeritics® brand Autopore III® model device. The total pore volume TPV (i.e., the pore volume between 1 Å and 8 μm) is calculated by the mercury intrusion pore volume V Hg and is deduced from the measurement of the accessible volume by helium porosimetry. The specific surface area is determined in the present invention by the BET method (which is described in the same reference book as mercury porosimetry), more particularly by standard ASTM D3663-03.

[0046] The grain-to-grain crushing (GGC) value is obtained through a standard test (standard ASTM D4179-01), which consists in subjecting millimeter bodies, for example, carriers in extruded form or in the form of beads or pellets, to a compressive force that, in the present case, causes fracture. This test is used to indirectly measure the strength of a material. The analysis is repeated individually and for a given number of particles, typically between 50 and 200, preferably between 100 and 200 particles. The average of the measured lateral crushing forces during crushing constitutes the average GGC, expressed in units of force (N) for spherical particles.

[0047] Selection of hollow microspheres according to the present invention Preferably, the hollow microspheres contained in the carrier according to the invention are selected from hollow microspheres obtained as by-products of other processes, in particular combustion by-products, or industrially produced hollow microspheres, in particular made from glass.

[0048] Therefore, according to one embodiment, they may be a by-product of coal combustion, particularly in coal-fired power plants; they are sometimes designated under the term "cenospheres." Formed from hollow microspheres of aluminum silicate, a material similar to glass, their cavities are filled with a mixture of nitrogen, oxygen, and carbon dioxide. These are the lightest particles contained in fly ash.

[0049] According to another embodiment, they may be industrially produced hollow microspheres, in particular hollow microspheres made from glass, such as the hollow glass microspheres sold by 3M under the name "3M® Glass Bubbles", which are made from soda-lime borosilicate glass.

[0050] (Selection of the matrix of the catalyst support according to the present invention) Preferably, the matrix of the support of the catalyst support according to the invention comprises at least one of the following carbonates / oxides / hydroxides: aluminium, titanium, silicon, zirconium, zinc, magnesium, copper, nickel, iron or cerium oxide.

[0051] According to one embodiment, it is prepared from the corresponding oxide or hydroxide.

[0052] According to one embodiment, the support of the catalyst support according to the invention is made essentially of clay and / or zeolite, alone or in a mixture with the preceding ones.

[0053] According to one embodiment, the support of the catalyst support according to the invention is made essentially of alumina and / or silica, alone or in a mixture with the preceding ones.

[0054] According to one embodiment, the support of the catalyst support according to the invention is made essentially of titanium oxide, alone or in a mixture with the preceding ones.

[0055] According to yet another embodiment, the support of the catalyst support according to the invention may also be made from carbonates, for example copper, zinc or nickel carbonates, alone or in mixture with the preceding ones.

[0056] Optionally, the support of the catalyst support according to the invention may also contain doping compounds, for example oxides selected from the group consisting of boron oxide, zirconia, titanium oxide and phosphorus pentoxide, the content of which is between 0.1% and 3% by weight.

[0057] Alumina-based supports include, for example: - from alumina gel or pseudoboehmite gel; or - from alumina derived from the rapid dehydration of hydrargillite, known as "flash" alumina; or - From a mixture of these different types of alumina It is prepared.

[0058] Flash alumina or alumina derived from rapid dehydration of hydrargillite is derived from the rapid dehydration of Bayer hydrate (hydrargillite) using a flow of hot gas, the inlet temperature of the gas in the apparatus typically varying from approximately 400 to 1200°C, and the contact time of the alumina with the hot gas typically being between less than 1 second and 4-5 seconds.

[0059] Pseudoboehmite gel or alumina gel can be obtained by basic precipitation of aluminum salts, such as aluminum chloride, aluminum sulfate, aluminum nitrate or aluminum acetate, or by hydrolysis of aluminum oxides, such as aluminum trioxide.

[0060] The alumina gel can be used as is or can be subjected to treatment prior to the paste preparation step to adjust the alkali content in the paste. A NaO content of less than 0.5% by weight may be suitable.

[0061] The catalyst support according to the present invention also retains a pore distribution that is substantially the same / similar to the pore distribution of a support lacking hollow microspheres.

[0062] A catalyst support according to the present invention has a matrix incorporating hollow microspheres, which has a pore distribution that is substantially the same / similar to the pore distribution of a support having the same matrix but lacking the hollow microspheres and which would be produced by the same method.

[0063] Therefore, by maintaining the same type of porosity, the matrix maintains the same properties related to porosity, in particular its capacity for impregnation with the active catalytic phase in the case of a support intended to receive the active catalytic phase, and its ability to obtain the desired catalyst / adsorbent performance qualities.

[0064] For example, if a catalyst support lacking hollow microspheres (and therefore consisting only of a matrix according to the terminology of the present invention) does not contain macropores, a catalyst support containing porous microspheres will also lack macroporous pores. If a catalyst support lacking hollow microspheres exhibits a unimodal or bimodal pore distribution, a catalyst support containing hollow microspheres will retain this unimodal or bimodal distribution, respectively.

[0065] The term "substantially the same / similar porous texture" is understood herein to mean: - Parameter V Hg / V 粒体 The "mercury intrusion pore volume / granular volume" is substantially the same; the pore distribution is substantially identical, i.e. the difference in the pore diameter corresponding to each pore volume is between plus or minus 30 Å, preferentially between plus or minus 15 Å.

[0066] Preferentially, when the catalyst support according to the invention contains mainly, in particular essentially, alumina, it exhibits a total pore volume (TPV) of 0.60 cm 3 or less. 3 / g or more, preferably 0.65 cm 3 / g or more.

[0067] Preferentially, when the catalyst support according to the invention mainly, in particular essentially, contains titanium dioxide, it exhibits a total pore volume TPV of 0.25 cm 3 3 / g or more, preferably 0.35 cm 3 / g or more, especially when the support contains only titanium dioxide.

[0068] Preferentially, when the support contains mainly, in particular essentially, alumina, the catalyst support according to the invention exhibits a specific surface area of ​​at least 10 m 2 / g, at least 50m 2 / g, at least 120m 2 / g, preferably at least 150m 2 / g. The maximum specific surface area is 1000m2 / g.

[0069] Preferentially, when the support mainly, in particular essentially, contains titanium dioxide, the catalyst support according to the invention exhibits a specific surface area of ​​at least 20 m 2 / g and up to 1000m 2 / g, preferentially up to 450m 2 / g.

[0070] Process for the preparation of extrudates according to the invention In a first alternative form, the support according to the invention is produced by an extrusion method, i.e. a method comprising an extrusion step. In this case, the method for preparing the support according to the invention comprises the following steps: - step i of preparing a paste containing hollow microspheres; - step ii of extrusion of said paste; - Drying stage iii; - baking stage iv; - optional hydrothermal treatment step v Includes:

[0071] Step i of the preparation of the paste containing hollow microspheres can then comprise different steps according to different embodiments, in particular the three embodiments described below.

[0072] (Step i of paste preparation) (First embodiment) In a first embodiment, step i of the preparation of the paste comprises the following steps: a1 The starting material is a powder that can be used for the production of a catalyst support; b1 rehydrating the powder; c1. Kneading the rehydrated powder in the presence of hollow microspheres.

[0073] Advantageously, in this first embodiment, the powder is chosen from alumina derived from the rapid dehydration of hydrargillite, alumina gel, hydroxides of alumina, carbonates, titanium dioxide, clay, silica, zeolites, copper oxide or zirconium oxide, used alone or in mixtures.

[0074] The step b1 of rehydration of powders that can be used for the manufacture of catalyst supports comprises: Step b11 of contacting the powder and water. This step is preferentially carried out in a kneader-type equipment, in which the powder is brought into contact with water. Optionally, complexing and / or dispersing agents may be employed. Preferably, the temperature during this step is between 50 and 100°C, and its duration is between 3 and 72 hours.

[0075] Step b12 of filtration of the suspension obtained at the end of step b11. This step is carried out in a filter and a cake is recovered, which can optionally be washed with water.

[0076] Optionally, step b13 is drying under conditions that allow the rehydrated powder, e.g., rehydrated alumina, to remove the impregnated water but not the water bound to the powder, e.g., alumina powder. For this reason, the drying temperature is up to 250°C. For example, the cake can be dried at a temperature of 60-150°C. Preferably, the cake is dried so that the dried rehydrated powder, e.g., dried alumina powder, exhibits a loss on ignition of 20%-40%, measured by calcination at 1000°C.

[0077] Step c1 of kneading the optionally dried rehydrated powder from step b1 is preferentially carried out directly in the presence of hollow microspheres, optionally in the presence of pseudoboehmite gel and / or in the presence of an acid. The kneading step is carried out by any method known to those skilled in the art, in particular by means of a Z-arm kneader or a twin-shaft mixer.

[0078] Optionally, the kneading stage c1 is carried out in the presence of additives making it possible to improve the efficiency of the kneading known to those skilled in the art, such as plasticizers or binders.

[0079] In a first alternative form, the step c1 of kneading the rehydrated powder is carried out in the presence of the rehydrated powder, for example pseudoboehmite gel, preferably in a content of 1% to 30% by weight relative to the rehydrated powder, for example rehydrated alumina.

[0080] A second alternative, which may possibly be combined with the first, is that the step c1 of kneading the rehydrated powder is carried out in an acidic medium. In this case, it is preferable to neutralize the paste at the end of the kneading step. This neutralization can be carried out using a base, which is usually introduced at the end of kneading into the kneader.

[0081] Typically, the content of the acid used is about 0.1% by weight to 15% by weight relative to the content of the oxide.

[0082] Typically, the content of the base used is about 0.1% by weight to 10% by weight relative to the content of the oxide.

[0083] Preferentially, in this first embodiment, the powder that can be used for the manufacture of the support is alumina. The steps of preparing the paste then comprise the following steps: a1 The starting material is an alumina powder derived from the rapid dehydration of hydrargillite; b1 Rehydrating the starting alumina; c1. Mixing rehydrated alumina in the presence of hollow microspheres.

[0084] (Second embodiment) In a second embodiment, step i of the preparation of the paste comprises the following steps: a2 The starting material is pseudoboehmite gel; b2 Kneading the pseudoboehmite gel in the presence of water and hollow microspheres.

[0085] In this embodiment, the pseudo-boehmite gel contains alumina hydrate and is therefore already partially hydrated.

[0086] The step b2 of kneading the pseudo-boehmite gel is carried out in the presence of water and hollow microspheres, and optionally in the presence of a pore-forming agent and / or an acid. The kneading step can be carried out in any manner known to those skilled in the art, in particular by means of a Z-arm kneader or a twin-shaft mixer.

[0087] Optionally, the kneading stage b2 is carried out in the presence of additives making it possible to improve the efficiency of the kneading, such as plasticizers or binders, known to those skilled in the art.

[0088] The step b2 of kneading the rehydrated powder is preferentially carried out with a water content necessary to obtain a paste with a rheology compatible with the subsequent extrudate.

[0089] Typically, the acid content is about 0.1% by weight to 15% by weight relative to the oxide content.

[0090] In some cases, step b2 of kneading the rehydrated powder is carried out in an acid medium. In this case, it is preferable to neutralize the paste at the end of the kneading step. This can be done with a base. The neutralizing agent is usually introduced into the kneader at the end of the kneading.

[0091] Typically, the acid content is about 0.1% to 15% by weight relative to the oxide content.

[0092] Typically, the content of the base used is about 0.1% by weight to 10% by weight relative to the content of the oxide.

[0093] (Third embodiment) A third embodiment of the paste containing hollow microspheres comprises the following steps: a3 The starting material is a powder, in particular an alumina powder derived from the rapid dehydration of hydrargillite; b3 forming the powder into beads in the presence of a pore-forming agent; c3 aging the beads; d3 After aging, the beads are kneaded in the presence of hollow microspheres.

[0094] The step b3 of forming into beads can be carried out by any technique known to those skilled in the art. It is carried out directly on the powder, in particular on the alumina powder, by means of a rotating technique. The term "rotating technique" is understood to mean any device on which the agglomeration is carried out by contacting and rotating the product to be granulated. As a device of this type, mention may be made of a rotary granulator or a rotating drum.

[0095] The size of the resulting beads is not critical: it is generally between 1 and 5 mm.

[0096] Step c3, maturing the beads from step b3, is carried out by maintaining the alumina beads in an atmosphere with controlled humidity. The temperature is preferentially between 30 and 100°C, preferably between 80 and 100°C. The duration of maturation can vary between a few hours and several tens of hours, preferably between 6 and 24 hours.

[0097] A practical embodiment of aging consists of injecting steam over the alumina beads.

[0098] The step d3 of kneading the beads resulting from the maturation step b3 is carried out in the presence of water and an acid to break them down and obtain a homogeneous paste that can be extruded. The acid used can be a strong or weak acid.

[0099] The amount of acid relative to the alumina is generally between 0.1% and 15% by weight, more preferentially between 0.5% and 10% by weight, relative to the oxide content.

[0100] The kneading can be carried out by any method known to those skilled in the art, in particular by means of a Z-arm kneader or a twin-shaft mixer.

[0101] (pore-forming agent) Optionally, in the three preceding embodiments of step i, the kneading step is carried out in the presence of one (or more) pore-forming agents. As pore-forming compounds used, mention may be made, for example, of wood flour, charcoal, sulfur, tar, plastics or plastic emulsions, such as polyvinyl chloride, polyvinyl alcohol, naphthalene, etc., and generally all organic compounds that are easily removed by calcination. Neither the amount of pore-forming compounds added nor their size is critical. Generally, the amount of pore-forming agent is between 1% and 30% by weight relative to the rehydrated powder under consideration, for example, rehydrated alumina.

[0102] (Step ii) of extrusion of the paste Step ii) of extrusion of the paste resulting from preparation step i) is carried out in an extrusion die, for example using a piston or extrusion screw, preferentially without intermediate steps, to give the catalyst support according to the invention in the form of extrudates.

[0103] This extrusion step can be carried out by any method known to those skilled in the art.

[0104] The extrusion step is preferentially carried out in a temperature range of 5°C to 100°C, preferentially at ambient temperature. The extrusion step is carried out so that the paste leaves the extrusion die at a pressure of 1.0 to 20.0 MPa, preferentially at a pressure of 3.0 to 9.5 MPa. The skilled person will adjust the viscosity of the paste to the extrusion pressure range, if necessary, by adjusting the water content of the paste.

[0105] Preferably, the extrudates of the catalyst support according to the invention have a diameter of at least 0.3 mm, preferably at least 0.8 mm, and / or at most 10 mm, preferably at most 4.0 mm. Their length is preferentially between 1 and 20 mm, preferably between 2 and 10 mm. Due to these dimensions, the extrudates of the catalyst support according to the invention, when employed in a catalyst bed, produce a limited pressure drop while possessing satisfactory mechanical properties.

[0106] Preferentially, the extrudates of the catalyst support according to the invention have a grain-to-grain comminution (GGC) of at least 0.5 kg / mm, preferentially at least 0.8 kg / mm ​​and / or preferentially at most 10.7 kg / mm.

[0107] (Step iii) of drying the extrudate Step iii, drying the extrudates resulting from the extrusion step, is preferentially carried out directly after the extrusion step, for example in a stove or oven, the drying temperature being preferentially between 80 and 200°C, typically for a period of between 3 and 24 hours.

[0108] (Step iv) of calcining the extrudates Step iv of calcining the extrudates resulting from the drying step is preferentially carried out directly after the drying step in a stove or oven at a calcination temperature of 200°C to 1400°C, preferentially 400 to 1200°C, more preferentially 450 to 800°C, typically for a period of 1 to 8 hours. Typically, the humidity during this step is 0 to 800 g of water per kg of dry air. The calcination step is carried out at a temperature below the melting point of the hollow microspheres, preferentially at least 20°C below, more preferentially at least 50°C below.

[0109] Advantageously, the material of the hollow microspheres, and therefore the type of hollow microspheres, is chosen according to the calcination temperature of the catalyst support so that the melting point of the hollow microspheres is at least 20° C., preferentially at least 50° C., higher than the calcination temperature of the catalyst support.

[0110] Advantageously, if the hollow microspheres are industrially produced hollow microspheres, in particular those made from glass, the firing temperature is between 450° C. and 800° C. With microspheres made from borosilicate glass, even higher firing temperatures, up to 900° C., can be achieved. However, it is preferable to choose a firing temperature sufficiently below the melting point of the microspheres, not only to prevent them from melting, but also to prevent them from starting to soften; this therefore ensures that the microspheres do not deform.

[0111] Advantageously, when the hollow microspheres are hollow microspheres from by-products of combustion, in particular from coal-fired power plants, the calcination temperature is between 800°C and 1400°C.

[0112] The nature of the microspheres is therefore chosen according to the temperatures "seen" / experienced by the carrier in which they are incorporated during a calcination-type heat treatment.

[0113] The calcination temperature depends on the matrix targeted for the support and the properties targeted for the support, in particular those relating to porosity: thus, if the matrix of the support is based on alumina, calcination can be carried out at approximately 500°C to have a high accessible surface area and a relatively small pore size, whereas calcination at 900°C will lead to a smaller accessible surface area and a larger pore size.

[0114] Calcination stage iv is preferentially carried out, for example in a muffle furnace or traversing bed, by first creating a temperature gradient to control the temperature rise in the extrudates. The temperature gradient is typically 1-10°C per minute, starting from ambient temperature. The temperature of the calcination stage is then kept fixed, for example at a temperature of 450-800°C: for glass spheres, for a period of 1-3 hours. Finally, the drop in temperature of the calcination stage is carried out freely and gradually.

[0115] (>Optionally, step v of acid-water heat treatment in a closed atmosphere) The optional step v of hydrothermal treatment of the extrudates resulting from the calcination step, preferably in a closed atmosphere, is also called "autoclaving" and is preferentially carried out directly after the calcination step in an autoclave, in particular an autoclave of the type described in patent application EP 0387 109.

[0116] The temperature during autoclaving may be 150-250°C for a period of 30 minutes to 3 hours.

[0117] The treatment can be carried out under the saturated vapor pressure corresponding to the treatment temperature or under a water vapor partial pressure at least equal to 70% of the saturated vapor pressure.

[0118] This hydrothermal treatment in a closed atmosphere therefore consists here of a treatment by passage through an autoclave in the presence of water at a temperature higher than ambient temperature. During this hydrothermal treatment, the alumina, or more generally the shaped support according to the invention, can be treated in different ways. Thus, the alumina can be impregnated with an acid before its passage through the autoclave, the autoclaving of the alumina being carried out either in the gas or liquid phase, the gas or liquid phase of the autoclave being possible or not being acidic. This impregnation can be carried out dry or by immersion of the alumina in an acidic aqueous solution prior to autoclaving. The term "dry impregnation" is understood to mean bringing the alumina into contact with a volume of solution that is less than or equal to the total pore volume of the alumina to be treated. Preferably, the impregnation is carried out dry.

[0119] (Method for the production of beads / spheres by oil droplet solidification) In a second alternative form, the support according to the invention is produced by the oil drop congealing method. In this case, the method for preparing the support according to the invention preferentially comprises the following steps: - stage v of the preparation of the suspension; - step vi of adding microspheres and / or pore formers; - step vii of mixing the suspension; - step viii) of forming spherical particles by oil droplet solidification starting from the mixture obtained in step c); - stage ix of drying; - Baking stage x.

[0120] Document US 2 422 499 describes the principle of a method for producing spherical particles (or beads) by oil droplet solidification. This technique consists of preparing an aqueous carrier sol, in particular an aqueous carrier sol of alumina (boehmite), and discharging it as fine droplets through a nozzle into a column containing an upper water-immiscible phase and a lower aqueous phase. The particles are shaped during their passage through the water-immiscible phase and then solidify in the aqueous phase. Once collected, the particles are washed, dried and calcined. Spherical alumina particles are thus obtained.

[0121] The macropore median diameter D of the spherical alumina particles according to the present invention 50 is between 0.05 μm (50 nm) and 30 μm (30,000 nm), as seen by electron microscopy. According to a first alternative form, in particular when a solid pore former is used for the preparation of spherical alumina particles, the macropore median diameter is between 0.05 μm (50 nm) and 30 μm (30,000 nm), preferably between 1 μm (1,000 nm) and 5 μm (5,000 nm).

[0122] It can be, for example, 500 micrometers to 5 mm for hollow microspheres on the order of 20 to 100 micrometers in diameter.

[0123] The spherical particles according to the invention exhibit a degree of intraparticle macroporosity that is advantageously less than 30%, preferably less than 25%, particularly preferably less than 20% of the total pore volume.

[0124] (Step V of the preparation of the suspension) The suspension of step v is prepared by mixing one or more types of boehmite powder in an acidic aqueous solution under vigorous stirring.

[0125] During the preparation of the boehmite suspension, it is possible to add an alumina filler. The amount of filler employed, expressed as weight percent of Al2O3, is not more than 30% by weight relative to the total weight of the suspension in terms of Al2O3. This filler may be selected from the group formed by the "transition" aluminas, including at least one of the rho, chi, eta, gamma, kappa, theta, delta and alpha phases. The alumina filler may be in the form of a powder or particles of alumina obtained by grinding and sieving shaped alumina bodies; these particles have a median diameter D 50 is, after grinding, no greater than 50 μm, preferably less than 30 μm, even more preferably less than 20 μm.

[0126] The content of acid contained in the suspension is such that the ratio of the weight of said acid to the dry weight of the source(s) of boehmite and filler (if present in the suspension) is 0.5% to 20% by weight, preferably 1% to 15% by weight. By way of example, the aqueous acid solution is a solution of a strong inorganic acid, such as HNO or HSO. The proportion of water contained in the suspension is calculated so that the ratio of the dry weight (corresponding to the weight of the boehmite powder plus any filler, expressed as AlO equivalent) to the total weight of water in the mixture is 10% to 50% by weight, preferably 15% to 40% by weight.

[0127] Optionally, the suspension may contain salts of one or more elements selected from groups IA, IIA, IIIA, IVA and VA, which act as promoters in the catalyst described below. These elements will therefore be incorporated into the final spherical particles after drying and calcination. The proportion of metal salt(s) is calculated so that the content by weight of elements from groups IA, IIA, IIIA, IVA and VA in the final product, after calcination, is between 0.01% and 2% by weight, preferably between 0.05% and 1% by weight.

[0128] (Step 6 of adding microspheres and pore formers) Step vi of adding microspheres and pore formers consists of: - adding to the suspension hollow microspheres, preferably having a diameter of less than or equal to 100 μm, more preferentially less than or equal to 80 μm; - A pore former is added to the suspension.

[0129] Pore-forming agents are in particular those described in patent EP 3 090 986.

[0130] This stage is simultaneous with the preceding stage, stage v.

[0131] In a first alternative form, the pore-forming agent is a solid pore-forming agent having a particle size of 0.05 to 30 μm in the suspension obtained in step a).

[0132] A second alternative, which may optionally be combined with the first, is that the pore-forming agent is a liquid pore-forming agent, in which case an emulsion comprising a liquid pore-forming agent, at least one surfactant and optionally water, or at least one liquid pore-forming agent, at least one surfactant and water in suspension of step a) is added to the suspension.

[0133] It is also possible to add the liquid pore-forming agent, surfactant and optional water directly to the aqueous suspension containing boehmite, i.e., by adding them simultaneously or in successive steps, without prior emulsion formation, in which case the same proportions of the various components described below are used.

[0134] (Step vii) Forming spherical particles by solidifying oil droplets According to step vii of the preparation method, spherical particles are shaped by oil droplet solidification starting from the mixture obtained in step vi.

[0135] This method consists of passing the mixture obtained in step vi, for example the (alumina + pore former suspension) mixture, through a discharge jar consisting of a nozzle with an orifice of calibrated size to form droplets. The discharge jar is placed at the top of a column containing an upper organic phase and a lower phase consisting of a basic aqueous phase. The organic phase is chosen so that it exhibits a density slightly lower than that of water.

[0136] Preferably, step vii of shaping the particles comprises the steps of: vii1) transferring the mixture to a discharge jar equipped with a nozzle, the orifice of the nozzle being calibrated to form droplets of at least 500 micrometers; vii2) The mixture is drained by gravity into a column containing an organic phase on top and a basic aqueous phase on the bottom, collecting the spherical particles at the bottom of the basic aqueous phase.

[0137] The shaping of the spheres occurs during the passage of the droplets through the organic phase, while gelation (or solidification) occurs in the aqueous phase. Surfactant-type additives may be added to the aqueous phase to facilitate the passage of the droplets through the interface and the solidification of the particles in the basic aqueous phase.

[0138] In the context of the present invention, the immiscible organic phase may be selected from fats, mineral oils and waxes, fatty substances, hydrocarbons and petroleum fractions. Preferably, the organic phase is a paraffinic fraction formed from normal paraffins and isoparaffins, having 10 to 14 carbon atoms, and exhibiting a boiling point of 220 to 350°C.

[0139] The basic aqueous phase is, for example, a solution of aqueous ammonia, ammonium carbonate or an amine. Preferably, the basic aqueous phase is a solution of aqueous ammonia.

[0140] Compounds such as urea can also be introduced into the suspension of step a) and then decomposed in the lower aqueous phase of the column, which compound allows easier control of the increase in viscosity according to patent US 4 542 113.

[0141] At the end of the step of forming spherical particles, the particles are recovered and separated from the aqueous phase, for example on a sieve. As taught in application EP 0 001 023, the particles thus formed can also be subjected to one or more maturation steps.

[0142] (>Drying stage ix) According to step ix of the preparation process, the particles obtained in step viii are dried.

[0143] Step ix of drying the spherical particles according to the method of the present invention is carried out at a temperature of 40 to 150°C under dry or humid air, typically for 30 minutes to 20 hours. The drying protocol can optionally include one or more static temperature phases. It can optionally require variable humidity during drying, preferably 10 to 1000 g of water per kg of dry air, and even more preferably 40 to 1000 g of water per kg of dry air.

[0144] (>Baking stage x) According to step x of the preparation method, the particles obtained in step ix are calcined.

[0145] The stage x of calcination of the spherical particles is carried out at a temperature between 450 and 900° C., preferentially between 550 and 800° C., for a period of 0.5 to 12 hours, preferably between 1 and 8 hours, more preferably between 1 and 5 hours. This calcination stage can include one or more stationary temperature phases.

[0146] Advantageously, the calcination step is carried out at a temperature below the melting point of the hollow microspheres, preferentially by at least 20°C, more preferentially by at least 50°C.

[0147] Advantageously, when the hollow microspheres are industrially produced hollow microspheres, in particular those made from glass, the firing temperature is between 450°C and 900°C, preferentially between 550°C and 800°C, for a period of 0.5 to 12 hours, preferably between 1 and 8 hours, more preferably between 1 and 5 hours.

[0148] Calcination stage iv is preferentially carried out by first creating a temperature gradient, for example in a muffle furnace or a traversed bed, to control the temperature rise in the extrudate. The temperature gradient is typically 1-10°C per minute, starting from ambient temperature. The temperature of the calcination stage is then kept fixed, for example at a temperature of 500-650°C, for a period of 1-3 hours. Finally, the drop in temperature of the calcination stage is carried out freely and gradually.

[0149] (Manufacturing method by granulation to give fine granules) In a third alternative form, the carrier according to the invention is shaped into the form of granules by a granulation method. In this case, the method for preparing the carrier according to the invention preferentially comprises the following steps: Step xi of granulating the paste containing hollow microspheres; Drying stage xii, Firing stage xiii, Optionally, hydrothermal treatment step xiv.

[0150] Granulation step xi comprises the following steps: the starting material is a powder in the presence of hollow microspheres and optionally a pore former (the same type of pore former as in the preparation of the support by extrusion described above); - forming the powder into beads; - Allowing the beads to age.

[0151] The step of shaping the powder in the form of granules in the presence of hollow microspheres can be carried out by any technique known to those skilled in the art. It is carried out directly on the powder by a rolling technique. The term "rolling technique" is understood to mean any device on which agglomeration is carried out by contacting and rolling the product to be granulated. As devices of this type, mention may be made of rotary granulators or rotary drums.

[0152] The size of the resulting granules is not critical: it is generally between 1 and 5 mm.

[0153] The stage of maturing the granules from the preceding stage is carried out by maintaining the alumina beads in an atmosphere with controlled humidity. The temperature is preferentially between 30 and 100°C, preferably between 80 and 100°C. The duration of maturation can vary between a few hours and several tens of hours, preferably between 6 and 24 hours.

[0154] A practical embodiment of aging consists in injecting vigorous steam onto the alumina beads.

[0155] Drying step xii is carried out in the same manner as drying step iii of the extrusion process.

[0156] The calcination step xiii is carried out in the same manner as the drying step iv of the extrusion process.

[0157] The optional hydrothermal treatment step xiv is carried out in the same manner as the hydrothermal treatment step v of the extrusion process.

[0158] Method for the preparation of catalysts from supports according to the invention and their use The carrier according to the invention or the carrier derived from the process according to the invention can be used as a catalyst, a carrier for a catalyst or an adsorbent. Those skilled in the art will know that the catalyst carrier can then be converted into a catalyst; details will therefore not be considered.

[0159] The catalyst support according to the present invention can be particularly used for producing catalysts for hydrotreating, hydroconversion, selective hydrogenation, hydrocracking, reforming, isomerization, DeNOx or selective catalytic reduction (SCR) processes, and / or Claus processes in the steam reforming, cracking, dehydrogenation, or dehydrocyclization of hydrocarbons or other organic compounds. Generally, metals are deposited / impregnated on the catalyst support according to the present invention by techniques well known to those skilled in the art, for example, by impregnation starting from a solution of the metal precursor. Impregnation can be carried out, for example, by the known form of dry impregnation, in which the desired amount of the element in the form of a soluble salt is introduced into a selected solution, for example, demineralized water, filling the porosity of the support as precisely as possible. The support thus filled with the solution is preferably dried. A suitable support is alumina, which can be prepared from any type of precursor and shaping tool known to those skilled in the art.

[0160] The metals may be deposited by co-impregnation or by sequential addition.

[0161] Typically, metals, such as cobalt and molybdenum, are deposited on the support in a single step by dry impregnation of the support with a solution containing the desired amounts of metals, in this example cobalt and molybdenum.

[0162] Alternatively, according to a second embodiment, in a first step, a first metal is deposited by impregnation, followed by a second metal, for example, cobalt and then molybdenum, or vice versa, molybdenum and then cobalt, by impregnation. According to a third embodiment, a first step of impregnation of two metals, for example, cobalt and molybdenum, on a support is carried out. A second impregnation of only one of the two metals is then carried out to adjust the molar ratio between the two metals. In this second or third embodiment, the impregnated support is dried and optionally calcined prior to the second impregnation.

[0163] Optionally, doping elements, such as phosphorus or boron, may be added to the impregnation solution.

[0164] After the introduction of the metal and optional doping agent, the support according to the invention is preferentially subjected to a calcination treatment. The purpose of this treatment is to convert the molecular precursor of the metal into an oxide phase. In this case, it is an oxidation treatment, but simple drying of the support can also be performed. Preferably, the support according to the invention is subjected to a calcination treatment before its use in the method according to the invention. The calcination treatment is advantageously carried out in air or diluted oxygen at a temperature between 200°C and 550°C, preferably between 300°C and 500°C. Here again, it should be noted that, according to the invention, the calcination temperature remains below the melting point of the hollow microspheres and is preferably chosen to have the same temperature difference as the calcination carried out on the support before impregnation with the metal.

[0165] It should be noted that the catalysts prepared from the supports according to the invention exhibit a reduced density compared to catalysts produced from conventional supports without hollow microspheres, and their porous texture is substantially the same as that of catalysts from supports lacking hollow microspheres.

[0166] (Example) The following examples illustrate the present invention but do not, however, limit the scope of the invention.

[0167] A series of catalyst supports are prepared with and without hollow microspheres. The hollow microspheres used according to the present invention are of several types, which are described in detail below: The indicated thermal stability should be understood as the temperature above which the microspheres undergo a significant change in their properties, but do not melt (hence, a temperature below the melting point).

[0168] [Table 1]

[0169] (Series 1 of Examples) A first series of catalyst supports with and without hollow microspheres is prepared by an extrusion method comprising step i of the preparation of a paste according to the second embodiment.

[0170] The starting material is an ultrafine, tabular pseudoboehmite gel or alumina gel, which is kneaded in the presence of an aqueous solution and hollow microspheres of a content according to the test, without the addition of acid, and the loss on ignition during acid kneading, i.e., after the addition of the acid solution (measurement known under the acronym PAFa), is 59% to 60%.

[0171] The resulting paste is kneaded for 15 minutes, after which it is neutralized with a basic solution and kneaded again for 5 minutes.

[0172] The resulting paste is forced through a 2.1 mm three-lobe die of a laboratory piston extruder at an extrusion pressure of 6.0-9.5 MPa.

[0173] The carrier is then dried in an oven at 140°C for 2 hours and then calcined at 600°C for 2 hours under humid air containing 40 g of water per kg of dry air, to obtain the carrier referred to as "Carrier 1" in Table 2 below.

[0174] The characteristics of the extruded supports obtained are summarized in Table 2 below (msp = spherical hollow microspheres).

[0175] [Table 2]

[0176] The pore size Dp is measured by conventional mercury porosimetry according to standard ASTM D4284-12 at a maximum pressure of 4000 bar, with a surface tension of 484 dyne / cm and a contact angle of 140° on the amorphous alumina support, to determine the pore size distribution of the sample.

[0177] Carriers 3 to 8 according to the present invention have absolute densities lower than those of comparative carriers 1 and 2, which do not contain hollow microspheres. The absolute density decreases as the absolute density difference ΔD abs As shown by the comparison of Fig. 1, the weight-saving power of microsphere A is greater than that of microsphere C due to the lower absolute density of microsphere A compared to that of microsphere C.

[0178] The preparation of Carriers 3 to 8 according to the invention is carried out at extrusion pressures in a range similar to that of Comparative Carriers 1 and 2, ie, 6.5 to 9.5 MPa.

[0179] The supports 3 to 8 according to the invention have a volume median pore diameter, noted as Dp, that is slightly less than or equal to that of the comparative supports 1 and 2.

[0180] The absolute densities of Carriers 3 to 8 according to the present invention are much lower than those of Comparative Carriers 1 and 2, but the mercury intrusion pore volume per particle volume (V Hg / V 粒体 ) are substantially identical to those of comparative carriers 1 and 2.

[0181] For all carriers, the results of the grain-grain crushing (GGC) test are good (greater than 0.8 kg / mm).

[0182] (Series 2 of Examples) A second series of catalyst supports with and without hollow microspheres is prepared by an extrusion method comprising step i of the preparation of a paste according to the second embodiment.

[0183] The starting material is an ultrafine plate-like pseudoboehmite gel or alumina gel, which is kneaded in the presence of an aqueous solution and hollow microspheres with a content according to this test, without added acid.

[0184] The resulting paste is kneaded for 15 minutes, after which it is neutralized with a base and kneaded again for 5 minutes.

[0185] The resulting paste is passed through a 2.1 mm four-lobe die of a prototype single-screw extruder to obtain extrudates.

[0186] The extruded support is subsequently dried in an oven at 140° C. overnight and then calcined at a temperature of 580° C. for 2 hours under humid air containing 40 g of water per kg of dry air.

[0187] The characteristics of the resulting extruded supports are summarized in Table 3 below; they are designated "Support 2" lacking the addition of hollow microspheres.

[0188] [Table 3]

[0189] The inventive carriers 10 and 11 exhibit lower specific densities and tapped bulk densities (TBD) than the comparative carrier 9, while exhibiting similar pore volumes per granule volume (V Hg / V 粒体 ) is maintained.

[0190] Furthermore, comparative support 9 and supports 10 and 11 according to the present invention have essentially unimodal pore distributions, with similar median pore diameters, and the percentage of pores of the same size (%) is approximately 80% by volume, as indicated by the % Unimodality column in Table 3 above. (D median+15A Volume in -D median-15A volume at (D median+30A Volume in -D median-30A This means that 80% of the volume median pore diameter + / - 30 Å falls within the median diameter + / - 15 Å range.

[0191] For all carriers, the grain-grain crushing (GGC) test results are good (greater than 0.8 kg / mm).

[0192] Specific surface area is m per gram of weight 2 As a result, the presence of porous microspheres in the carrier increases the specific surface area of ​​the carrier according to the invention. The specific surface areas of the carriers 10 and 11 according to the invention are comparable to that of the comparative carrier 9.

[0193] In view of the properties of the support 2 containing the microspheres A and C, the catalyst supports 10 and 11 according to the invention can be used for the production of catalysts.

[0194] (Series 3 of Examples) The preparation of a third series of catalyst supports with and without hollow microspheres is carried out by an extrusion method comprising step i of the preparation of the paste according to the second embodiment.

[0195] The starting material is titanium dioxide G5 powder sold by Tronox. It is rehydrated and the mixture is kneaded in the presence of an aqueous solution acidified with a strong inorganic acid, containing organic additives to promote extrusion, and hollow microspheres in a content according to the test. The resulting paste is kneaded for 30 minutes.

[0196] The resulting paste is forced through a 4 mm cylindrical die of a screw extruder to obtain extrudates.

[0197] The extruded supports are subsequently dried overnight in an oven at 140°C and then calcined for 2 hours at a temperature of 450°C under humid air containing 40 g of water per kg of dry air by weight. They are designated "Support 3" lacking the addition of hollow microspheres.

[0198] The characteristics of the resulting extruded supports are summarized in Table 4 below.

[0199] [Table 4]

[0200] The inventive carrier 13 exhibits a lower absolute density and tapped bulk density "TBD" than the comparative carrier 12.

[0201] The support 12 can be used as a first Claus reactor catalyst for the following reaction: 2H2S + SO2⇔3 / xS x + 2H2O CS2 + 2H2O → CO2 + 2H2S

[0202] A gas having the composition by volume set out in Table 5 below is fed into a reactor maintained at 320° C. The contact time between the gas mixture and the catalyst is 0.9 seconds.

[0203] [Table 5]

[0204] The degree of conversion of CS2 was measured at the outlet of the reactor by gas chromatography and is shown in Table 6 below.

[0205] [Table 6]

[0206] Measurement of catalytic activity in the hydrolysis of CS2 to give CO2 under first Claus reactor conditions shows that support 13 according to the invention is at least as effective as support 12 (comparison).

[0207] (Series 4 of Examples) The preparation of a fourth series of catalyst supports with and without hollow microspheres is carried out by the oil drop congealing method.

[0208] The starting material is boehmite of the Pural SB3 type sold by Sasol. A suspension containing 20% ​​inorganic matter (expressed as wt. % of Al2O3) is prepared by mixing a filler of γ-alumina having a volume median diameter of 50 μm and Pural SB3 boehmite powder in an acidified aqueous solution containing 3.6 wt. % HNO3 / Al2O3.

[0209] The Al2O3 solids fraction is contributed by 88 wt% by boehmite and 12 wt% by gamma-alumina filler. The suspension further contains a pore former and a surfactant. The pore former is an organic phase containing a mixture of paraffins containing 10-12 carbon atoms, with a boiling point of about 290°C and a density of 0.75 g / cm3. 3 The surfactant is Galoryl® EM10, a commercially available emulsifier. These compounds are introduced in the following proportions: pore-former / alumina weight proportion=14% and surfactant / pore-former weight proportion=7%. Microspheres are also added to the suspension if appropriate.

[0210] In this example, after the addition of all the compounds, the suspension is directly subjected to mixing until the viscosity of the mixture is 250-400 mPa·s. At this viscosity, the suspension exhibits suitable rheological properties for ejection through a nozzle, resulting in beads / spherical particles.

[0211] The beads are subsequently dried overnight in an oven at 140° C. and then calcined at a temperature of 580° C. for 2 hours under humid air containing 40 g of water per kg of dry air by weight.

[0212] The characteristics of the carriers obtained are summarized in Table 7 below: the carrier in the form of beads without the addition of hollow microspheres is called "carrier 4".

[0213] [Table 7]

[0214] The inventive carrier 15 exhibits a lower absolute density and tapped bulk density "TBD" than the comparative carrier 14.

[0215] In conclusion, the addition of hollow microspheres to supports as prepared according to the present invention is highly flexible in its implementation and allows for extremely significant weight reduction of the support, and hence of the catalysts incorporating them, without this weight reduction being obtained at the expense of the porosity characteristics or mechanical properties of the support.

Claims

1. 1. A calcined support, present in the form of extrudates, pellets, granules or beads, comprising a porous matrix based on clay, zeolite or on carbonates, oxides or hydroxides of metals and / or silicon, wherein the matrix incorporates inorganic hollow microspheres of different composition in a content of 0.3% to 15% by weight of the matrix, the ratio of the smallest dimension of the pellet or granule or extrudate or bead type support to the diameter of the hollow microspheres being at least 5 / 1.

2. 2. The carrier according to claim 1, wherein the content of hollow microspheres is 0.5% by weight to 15% by weight.

3. 3. A carrier according to claim 1 or 2, characterized in that the ratio of the smallest dimension of the carrier of the pellet or granule or extrudate or bead type to the diameter of the hollow microspheres is at least 8 / 1.

4. The median diameter D of the hollow microspheres ５０ The carrier according to any one of claims 1 to 3, characterized in that the particle size is 150 micrometers or less.

5. The median diameter D of the hollow microspheres ５０ The carrier according to any one of claims 1 to 4, characterized in that the particle size is 10 to 150 micrometers.

6. V, which is substantially identical to a carrier lacking hollow microspheres. Ｈｇ / V 粒体 and a pore distribution, i.e., the pore distribution has a difference in pore diameter corresponding to each pore volume of plus or minus 30 Å.

7. V, which is substantially identical to a carrier lacking hollow microspheres. Ｈｇ / V 粒体 and pore distribution, i.e., the pore distribution has a difference in pore diameter corresponding to each pore volume of plus or minus 15 Å.

8. 8. The carrier according to claim 1, wherein the hollow microspheres have an absolute density of 0.1 to 1.3 g / cm 3.

9. 9. The carrier according to claim 1, wherein the hollow microspheres have an absolute density of 0.25 to 0.85 g / cm 3.

10. 10. The carrier according to claim 1, wherein the melting point of the microspheres is at least 500°C.

11. 11. A carrier according to any one of claims 1 to 10, characterized in that the melting point of the microspheres is at most 1500°C.

12. 12. A carrier according to any one of claims 1 to 11, characterized in that the hollow microspheres are made from glass of the borosilicate glass type or from ceramic.

13. 13. Support according to any one of claims 1 to 12, characterized in that the metal carbonates, oxides or hydroxides of the matrix are chosen, alone or in mixtures, from at least one of the following compounds: carbonates / oxides / hydroxides of titanium, aluminium, copper, zirconium, zinc or silicon.

14. Catalyst, characterized in that it comprises a support according to any one of claims 1 to 13 and at least one element or compound which is catalytically active and which is impregnated and / or deposited on the matrix.

15. Catalyst, characterized in that it comprises a support according to any one of claims 1 to 13 and at least one element or compound selected from at least one element from group VIIIB or IB or IIB, which is catalytically active and which is impregnated and / or deposited on the matrix.

16. Catalyst, characterized in that it comprises a support according to any one of claims 1 to 13 and at least one element or compound which is catalytically active and which is chosen from one of the following elements: cobalt, molybdenum, nickel, palladium, platinum, rhodium, ruthenium, iron or tin, and which is impregnated and / or deposited on the matrix.

17. Use of a support according to any one of claims 1 to 13 as a catalyst or adsorption / absorption mass.

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