Method for preparing catalysts based on MFI zeolites having improved density and mechanical strength

Abstract

The present invention relates to an original process for preparing a catalyst in the form of extrudates, comprising an acidic zeolite with the structural code MFI, and a binder, and optionally containing a hydrogenation-active phase, the zeolite content being between 45% and 90% relative to the total mass of the catalyst, the process comprising at least: a) mixing the MFI zeolite and the binder, the average size of the elementary particles of the MFI zeolite being between 110 and 800 nm, b) adding a peptizing agent to the mixture, c) adding a neutralizing agent to the mixture, d) shaping the mixture by extrusion, e) optionally drying the solid, f) subjecting the solid obtained to a thermal treatment in the presence of water vapor at a temperature of 400 to 1000° C. in the presence of an air stream containing 1 to 60% by volume of water, and g) optionally introducing onto the solid one or more precursors of the hydrogenation-active phase.

Description

Field of the Invention

[0001] The present invention provides an original method for preparing a catalyst in the form of extrudates based on an acidic MFI zeolite (preferably H-ZSM-5) incorporated in high concentrations, an alumina-containing binder, and optionally a hydrogenation-active phase. The resulting catalyst type can be used in numerous heterogeneous catalytic applications requiring acid functionality, in particular for hydrocarbon conversions: methanol conversion (to olefins, to gasoline, etc.), olefin conversion (to olefins, to gasoline, to diesel, etc.), various processes for converting paraffins to aromatics, alkylation processes, and processes for dewaxing diesel, oils, plastic pyrolysis products, biomass pyrolysis products, etc. Existing technology

[0002] Patent US 3702886 claims solid ZSM-5 and a method for its preparation.

[0003] Patents US Pat. No. 5,063,187 and US Pat. No. 7,229,941 disclose catalysts based inter alia on ZSM-5 zeolite, which have a zeolite primary crystal structure and a specific agglomerate size of the primary crystals of the zeolite.

[0004] Patent US 4206085 discloses a catalyst based on a zeolite / binder matrix having improved attrition resistance.

[0005] Patent application US 2019 / 0247837 discloses a method for preparing a hydrocracking catalyst containing ZSM-5 zeolite, a binder and a hydrogenation phase.

[0006] Patent CN1 06608779 discloses a catalyst for producing propylene by catalytic cracking, wherein the catalyst comprises ZSM-5 zeolite, a binder and a rare earth element.

[0007] US Patent No. 4,788,377 discloses a method for producing olefins from alcohols using steam-treated ZSM-5 zeolite.

[0008] In order to ensure high catalytic performance, a high zeolite content must generally be achieved.The role of the binder in shaped zeolite catalysts is to ensure cohesion of the units and thus sufficient mechanical strength for use as a catalyst.

[0009] Thus, a high content of zeolitic phase may lead to brittleness in the units, or a high binder content in order to ensure good mechanical strength may limit the catalytic performance.

[0010] Subject matter of the invention

[0011] The present invention provides an original process for preparing a catalyst in the form of extrudates, comprising an acidic MFI zeolite, preferably H-ZSM-5, and a binder, preferably alumina, and optionally a hydrogenation-active phase, the zeolite content being between 45% and 90% relative to the total mass of the catalyst, the process comprising at least the following steps:

[0012] a) mixing the MFI zeolite and a binder, the average size of the elementary particles of the MFI zeolite being between 110 and 800 nm, preferably between 120 and 700 nm, very preferably between 150 and 500 nm, as measured by scanning electron microscopy,

[0013] b) adding to the mixture obtained in step a) a peptizing agent selected from nitric acid and a carboxylic acid selected from acetic acid, citric acid and butyric acid, alone or as a mixture,

[0014] c) adding to the mixture obtained in step b) a neutralizing agent selected from inorganic bases selected from sodium hydroxide, potassium hydroxide and ammonia, alone or as a mixture, and organic bases in solution, selected from amines and quaternary ammonium compounds, alone or as a mixture,

[0015] d) shaping the mixture obtained in step c) by extrusion to obtain a solid,

[0016] e) optionally drying the solid obtained in step d),

[0017] f) subjecting the solid obtained in step d) or e) to a thermal treatment in the presence of steam at a temperature of 400 to 1000° C. in the presence of an air stream containing 1 to 60% by volume of water,

[0018] g) optionally, introducing one or more precursors of the hydrogenation-active phase into the solid obtained in step f).

[0019] The proposed preparation scheme makes it possible to obtain a catalyst having a porosity different from that of the prior art by combining the various steps of preparing the support / catalyst in an original way. Specifically, despite the introduction of a high content of zeolite, the method for preparing the catalyst obtains an optimized pore volume (with minimized macroporosity and control of mesopore distribution), making it possible to fine-tune the volume content of the zeolite in the reactor (i.e., the density in kg / m3). The volume content of the zeolite in the reactor is defined as the product of the TPD (tapped bulk density) of the catalyst and the mass content of the zeolite in the catalyst. In addition, the method according to the present invention makes it possible to improve the mechanical properties that are crucial to supports with high zeolite content.

[0020] The catalyst type obtained according to the invention can be used in many heterogeneous catalytic applications requiring acid functions, in particular those for hydrocarbon conversion: for the conversion of methanol (into olefins, into gasoline, etc.), for the conversion of olefins (into olefins, into gasoline, into diesel, etc.), for various processes for converting paraffins into aromatics, alkylation processes, processes for the dewaxing of diesel, oils, plastic pyrolysis products, biomass pyrolysis products, etc.

[0021] Terminology and characterization techniques

[0022] The catalyst and support of the present invention have a specific pore distribution, wherein the macropore and mesopore volumes are measured by mercury intrusion porosimetry, and the micropore volume is measured by nitrogen adsorption.

[0023] The term "macroporous" is understood to mean pores with openings larger than 50 nm.

[0024] The term "mesopores" is understood to mean pores having an opening between 2 nm and 50 nm, inclusive.

[0025] The term "micropore" is understood to mean pores with an opening smaller than 2 nm.

[0026] In the following description of the present invention, the specific surface area is understood to mean the BET specific surface area determined by nitrogen adsorption according to standard ASTM D3663-78, which is based on the Brunauer-Emmett-Teller method described in the journal "Journal of American Society", 60, 309, (1938).

[0027] The macropore volume and the mesopore volume were measured by mercury intrusion porosimetry according to standard ASTM D4284-83 at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dynes / cm and a contact angle of 140°. The wetting angle used was taken to be equal to 140°, according to the recommendation of the publication “Techniques de l'ingénieur, traitéanalyse et caractérisation” (Techniques of the engineer, analysis and characterization treatise), by the authors Jean Charpin and Bernard Rasneur, pages 1050-5.

[0028] The value at which mercury fills all intercrystalline voids is set to 0.2 MPa, and it is considered that mercury penetrates into the pores of the sample above this value.

[0029] The macroporous volume of the catalyst or support is defined as the cumulative volume of mercury introduced at a pressure between 0.2 MPa and 30 MPa, corresponding to the volume contained in pores with an apparent diameter greater than 50 nm.

[0030] The mesopore volume of the catalyst or support is defined as the cumulative volume of mercury introduced at a pressure between 30 MPa and 400 MPa, corresponding to the volume contained in pores with an apparent diameter between 3.6 and 50 nm.

[0031] The micropore volume was measured by nitrogen porosimetry. The quantitative analysis of the microporosity was carried out by means of the "t" method (Lippens-De Boer method, 1965), which corresponds to a modification of the initial adsorption isotherm as described in the publication "Adsorption by powders and porous solids. Principles, methodology and applications" by F. Rouquérol, J. Rouquérol and K. Sing, Academic Press, 1999.

[0032] In the following description of the invention, the "total pore volume" of the alumina or the support or the catalyst is understood to mean the sum of the mesopore volume, the macropore volume (measured by mercury intrusion porosimetry) and the micropore volume (measured by nitrogen porosimetry).

[0033] The mechanical strength of the materials according to the invention is determined by the Single Particle Crush Strength (SPCS) test. This is a standardized test (standard ASTM D4179-01) which involves subjecting a material in the form of millimeter-sized units, such as beads, pellets, or extrudates, to a compressive force that causes the material to fracture. The analysis is repeated for a certain number of solids removed individually, typically between 10 and 200 solids. The average value of the measured lateral forces that cause the material to fracture constitutes the average SPCS, which is expressed in units of force (N) in the case of granules and in units of force per unit length (daN / mm or deca Newtons / mm of extrudate length) in the case of extrudates.

[0034] The loss on ignition (LOI) of a solid is the relative mass loss (expressed in %) of the solid after heating to 1000°C in a muffle furnace for 3 hours.

[0035] Tapped bulk density (TPD) is defined as the bulk density (bulk density) of the sample after the tapping. It is measured as follows: the carrier or material of a given weight are introduced into a graduated cylinder, to keep the agglomerates under a given volume. The cylinder is then vibrated until all sedimentations stop and reach constant volume. The weight of the agglomerates occupying a unit volume is then calculated. The bulk density (TPD) under the tapped state is measured according to standard NF EN ISO 787-11.

[0036] Description of SEM for particle size measurement

[0037] The size of the zeolite particles is measured by scanning electron microscopy at a magnification of 10,000 to 100,000 on a Zeiss Supra 40 instrument. The equivalent diameter is calculated for a number of units greater than 200 by any method known to those skilled in the art. The units are clearly demarcated from one another, without regard to agglomerates. The average size of the elementary zeolite particles is then calculated as the arithmetic mean of the measured equivalent diameters of each unit. The average size of the elementary particles is the number-average size.

[0038] In the following, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by DRLide, 81st edition, 2000-2001). For example, Group VIII according to the CAS classification corresponds to the metals of Groups 8, 9 and 10 according to the new IUPAC classification.

[0039] For the purposes of the present invention, the various embodiments presented can be used individually or in combination with one another, without any restrictions on their combination, as far as technically feasible.

[0040] For the purposes of the present invention, various ranges of parameters of a given step, such as pressure ranges and temperature ranges, may be used alone or in combination. For example, for the purposes of the present invention, a preferred range of pressure values may be combined with a more preferred range of temperature values. Detailed Description of the Invention

[0042] The present invention provides an original process for preparing a catalyst in the form of extrudates, comprising an acidic MFI zeolite, preferably H-ZSM-5, and a binder, preferably alumina, and optionally a hydrogenation-active phase, the zeolite content being between 45% and 90% relative to the total mass of the catalyst.

[0043] Catalyst preparation

[0044] According to the present invention, the catalyst comprises at least one MFI zeolite and a binder.

[0045] According to step a), the MFI zeolite is mixed with a binder. According to a preferred preparation method, the MFI zeolite and the binder can be mixed in the form of a powder, a ground powder, a suspension, or a suspension that has been subjected to a depolymerization treatment, but is not limited thereto. The zeolite and the binder can be advantageously mixed by mechanical mixing or by using a suspension whose concentrations are adjusted to the target final zeolite content and the target final binder content in the catalyst prepared according to the present invention.

[0046] MFI zeolite

[0047] MFI-type zeolites are crystalline microporous solids and have been described in the literature (GT Kokotailo, SL Lawton, DH Olson, WM Meiier, Nature, Vol. 272, pp. 437-438, 1978; DH Olson, G.T Kokotailo, SL Lawton, WM Meiier, J. Phys. Chem., Vol. 85, pp. 2238-2243, 1981; H. van Koningsveld, JC Jansen, H. van Bekkum, Zeolites, Vol. 10, pp. 235-242, 1990). The crystal structures of these materials are described in "Collection of simulated XRD powder patterns for zeolites", edited by MMJ Treacy and JB Higgins, 5th revised edition, 2007, pp. 280-281 and in "Atlas of zeolite framework types", C. Baerlocher, LB McCusker, DH Olson, 6th revised edition, 2007, pp. 212-213.

[0048] A process for preparing MFI-type zeolites is also described in said document.

[0049] The MFI zeolite has a chemical composition expressed in moles of oxides on an anhydrous basis, which is defined by the following general formula: (96-a)XO2:a / 2Y2O3:a / 2M 2 / n O, wherein X represents at least one tetravalent element, Y represents at least one trivalent element, M is at least one n-valent alkali metal and / or alkaline earth metal, and x<27.

[0050] X is preferably selected from silicon, germanium, titanium, and mixtures of at least two of these tetravalent elements; X is very preferably silicon, and Y is preferably selected from aluminum, boron, iron, indium, and gallium; Y is very preferably aluminum. M is preferably selected from lithium, sodium, potassium, calcium, magnesium, and mixtures of at least two of these metals, and M is very preferably sodium. Preferably, X represents silicon; when element Y is absent from the composition of the MFI zeolite, the MFI zeolite according to the present invention is a completely siliceous solid. It is also advantageous to use a mixture of several elements as element X, in particular a mixture of silicon with another element X selected from germanium and titanium, preferably germanium. Thus, when silicon is present as a mixture with another element X, the MFI zeolite according to the present invention is a crystalline metallosilicate that, in its calcined form, exhibits an X-ray diffraction pattern identical to that described in "Collection of simulated XRD powder patterns for zeolites," edited by MMJ Treacy and JB Higgins, fifth revised edition, 2007, pp. 280-281. Even more preferably and in the presence of element Y, wherein X is silicon and Y is aluminium: said MFI-type zeolite according to the present invention is an aluminosilicate.Preferably, said MFI-type zeolite according to the present invention is in the form of an aluminosilicate.

[0051] Preferably, the average size of the elementary particles of the MFI zeolite, measured by scanning electron microscopy, is between 110 and 800 nm, preferably between 120 and 700 nm, very preferably between 150 and 500 nm.

[0052] Preferably, the MFI-type zeolite is ZSM-5.

[0053] Preferably, the molar ratio Si / Al of the number of silicon atoms to the number of aluminum atoms is less than 100, preferably less than 70 and very preferably less than 50.

[0054] The MFI zeolite contained in the catalyst composition according to the invention is advantageously exchanged by at least one treatment with a solution of at least one ammonium salt, so as to obtain the ammonium form of the MFI zeolite which, upon calcination, gives the acid form (H + This exchange step can be carried out at any stage of the catalyst preparation, i.e. after the step of preparing the MFI zeolite, after the step of shaping the MFI zeolite with a porous mineral binder, or even after the step of optionally introducing the hydrogenation-dehydrogenation phase.

[0055] The MFI zeolite comprised in the catalyst composition used in the process according to the invention is advantageously at least partially, preferably substantially completely, in the acid form, i.e. H + form.

[0056] According to the invention, the zeolite content is between 45% and 90% and preferably between 50% and 80% by weight and very preferably between 55% and 75% by weight, relative to the total mass of the catalyst.

[0057] Adhesives

[0058] According to the invention, the catalyst used also contains a binder. The binder can advantageously be amorphous or crystalline. Preferably, the binder is advantageously selected from the following oxides or their hydrated forms: aluminum oxide, silicon dioxide, silicon dioxide / aluminum oxide, clay, titanium oxide, boron oxide and zirconium oxide, selected individually or as a mixture. Preferably, the binder is aluminum oxide or aluminum hydroxide, selected individually or as a mixture. Preferably, the binder is aluminum oxide in any form known to those skilled in the art, for example α-, γ-, η- or δ-aluminum oxide or a hydroxide such as boehmite, bayerite or gibbsite. The aluminum oxides differ in their specific surface area and their pore volume. The binder advantageously has a loss on ignition greater than 15%.

[0059] Preferably, the catalyst comprises from 10% to 60% by weight of binder, preferably from 20% to 50% by weight, relative to the total mass of the catalyst.

[0060] According to step b), a peptizing agent selected from nitric acid and carboxylic acids selected from acetic acid, citric acid and butyric acid, alone or as a mixture, is added to the mixture obtained from step a).Preferably, the peptizing agent is nitric acid.

[0061] The amount of peptizing agent can advantageously be defined as the total acid content, expressed as a percentage relative to the mass of dry binder introduced in step a), and is between 0.1% and 12% by weight. Preferably, the total acid content is between 0.1% and 6% by weight, very preferably between 0.1% and 4% by weight.

[0062] Water may also be introduced during step b) so that the loss on ignition of the mixture is between 20 and 80%, and preferably between 30 and 70%.

[0063] According to step c), a neutralizing agent is added to the mixture obtained from step b), the neutralizing agent being selected from an inorganic base selected from sodium hydroxide, potassium hydroxide, and ammonia, alone or in mixture, and an organic base in solution, the inorganic base being selected from amines and quaternary ammonium compounds, alone or in mixture. Preferably, the organic base in solution is selected from alkylethanolamines and ethoxylated alkylamines. The organic base is preferably used as a solution in water. Very preferably, the neutralizing agent is an inorganic base, and preferably ammonia, and preferably an aqueous ammonia solution (NH4OH).

[0064] The amount of neutralizing agent can be defined as the degree of neutralization, expressed as a molar percentage of base relative to the amount of acid introduced in step b), and is between 1 and 200%. Preferably, the degree of neutralization expressed as a molar percentage of base relative to the amount of acid is between 10 and 100%.

[0065] According to step d), the mixture obtained in step c) is formed by extrusion to obtain a solid. To facilitate this step, various additives can be added. Examples of additives include, in particular, cellulose, carboxymethyl cellulose, carboxyethyl cellulose, tall oil, xanthan gum, surfactants, flocculants such as polyacrylamide, carbon black, starch, stearic acid, polyacrylic alcohol, polyvinyl alcohol, biopolymers, glucose, polyethylene glycol, etc.

[0066] Extrusion can advantageously be carried out with any conventional commercially available tool. The mixture obtained from step c) is advantageously extruded through a die, for example using a piston or a single-screw or twin-screw extruder. This extrusion step can advantageously be carried out by any method known to those skilled in the art to obtain a solid or raw material.

[0067] The process according to the invention may also optionally comprise a step e) of drying the solid obtained in the shaping step d). Said drying step is advantageously carried out by any technique known to a person skilled in the art.

[0068] Preferably, drying is carried out in an air stream, which can be dry or moist. Drying can also advantageously be carried out in a stream of any oxidizing, reducing or inert gas. Drying is preferably carried out at a temperature between 50° C. and 180° C., preferably between 60° C. and 150° C., and very preferably between 80° C. and 130° C. Preferably, the drying step is carried out for a period of 2 to 10 hours.

[0069] According to step f), the heat treatment step of the solid obtained in step d) or e) in the presence of steam is carried out in the presence of an air stream containing 1 to 60% by volume of water at a temperature between 400 and 1000° C. for an advantageous period of 1 to 24 hours.

[0070] Preferably, step f) is carried out in the presence of an air stream having a water content of 1% to 50% by volume, and very preferably 1% to 10% by volume. Preferably, step f) is carried out at a temperature between 450° C. and 850° C. Preferably, step f) is carried out for a period of 2 to 10 hours.

[0071] The process according to the invention may also optionally comprise a step g) of introducing one or more precursors of the hydrogenation-active phase into the solid obtained in step f).

[0072] Preferably, the precursor(s) of the hydrogenation-active phase comprises at least one element from Group VIII and optionally at least one element from Group VIB. Preferably, the element from Group VIII is selected from nickel and cobalt, and very preferably, the element from Group VIII is nickel. When the hydrogenation phase comprises an element from Group VIB, it is preferably molybdenum or tungsten, very preferably molybdenum.

[0073] The precursor of the hydrogenated phase can advantageously be introduced by any method known to a person skilled in the art, such as dry impregnation, excess impregnation, ion exchange, and the like.

[0074] Preferably, the precursor of the hydrogenated phase is introduced by dry impregnation. The precursor of the hydrogenated phase can advantageously be introduced by one or more operations of impregnating the solid obtained in step f) with a solution containing at least one precursor of at least one metal selected from the elements of Group VIII and optionally at least one precursor of at least one metal selected from the elements of Group VIB. When more than one precursor is used, they are preferably introduced simultaneously. In the preferred variant in which the Group VIII element is nickel or cobalt and the Group VIB element is molybdenum or tungsten, examples of precursors that can be used in the catalyst preparation method are nickel nitrate, nickel dihydroxide, nickel acetate, nickel carbonate, cobalt nitrate, cobalt dihydroxide, cobalt acetate, cobalt carbonate, ammonium heptamolybdate, molybdic acid, molybdenum oxide, ammonium metatungstate, tungstic acid, or tungsten oxide. Any other compound known to those skilled in the art with sufficient solubility may also be used.

[0075] The impregnation of the precursor of the element chosen from the elements of group VIII and optionally the elements of group VIB may advantageously be facilitated by adding phosphoric acid to the aqueous solution.

[0076] In the case where step g) is included, the content of group VIII elements is advantageously between 0.1% and 10% by weight of oxides, preferably between 0.5% and 8% by weight of oxides and very preferably between 1% and 6% by weight of oxides relative to the total mass of the catalyst.

[0077] In the variant in which the hydrogenation-active phase comprises an element of group VIB, the content of the element of group VIB is advantageously from 1% to 40% by weight of oxide, preferably from 2% to 35% by weight of oxide and very preferably from 5% to 30% by weight of oxide, relative to the total mass of the catalyst.

[0078] The catalyst may also advantageously contain phosphorus: the phosphorus content is advantageously between 0.5% and 15% by weight of oxide P2O5, preferably between 1% and 10% by weight of oxide, relative to the total mass of the catalyst.

[0079] After impregnation with the constituent elements of the hydrogenated phase, the solid thus filled with the impregnation solution may optionally be subjected to a step h) of aging at room temperature for a period of 0.5 to 24 hours, preferably 1 to 6 hours.

[0080] After the impregnation and optional aging step, the solid is subjected to step i): drying for a period of 0.5 to 24 hours, preferably 1 to 12 hours. Drying is preferably carried out in an air stream, which may be dry or wet. Drying is preferably carried out at a temperature between 50° C. and 180° C., preferably between 60° C. and 150° C.

[0081] The dried, optionally aged solid is then optionally subjected to step j): calcination for a period of 0.5 to 24 hours, preferably 1 to 12 hours. The calcination step is advantageously carried out in the presence of molecular oxygen at a temperature advantageously ranging from 200° C. to 600° C., preferably from 300° C. to 500° C., for example by purging with air, which may be dry or wet.

[0082] The hydrogenation active phase of the catalyst used in the method according to the present invention is preferably used in a sulfided form. The sulfidation of the catalyst can be carried out in situ or non-situ by any method known to those skilled in the art. In the case of an in-situ sulfidation step, the catalyst is sulfided by treating it with a raw material containing at least one sulphur compound, which, once decomposed, causes sulphur to be fixed to the active phase. This raw material can be gaseous or liquid, such as hydrogen-containing H2S, or a liquid containing at least one sulphur compound. In the case of non-situ sulfidation, the sulphur compound can optionally be introduced into the catalyst in the presence of another compound. Subsequently, the catalyst is dried and then transferred to a reactor for implementing the method of the present invention. In this reactor, the catalyst is then treated with hydrogen to convert at least a portion of the main metal into a sulfide. A procedure particularly suitable for the present invention is the procedure described in patents FR-B-2 708 596 and FR-B-2 708 597.

[0083] Characteristics of the obtained catalyst

[0084] The preparation process according to the invention has the significant advantage that a porous zeolite catalyst is obtained which has a completely satisfactory mechanical strength in terms of its pore volume, as reflected in a single particle crushing strength (SPCS) value of preferably at least 0.8 daN / mm, very preferably at least 0.9 daN / mm.

[0085] The preparation process according to the invention makes it possible to obtain catalysts with a high zeolite content, said catalysts advantageously having a total pore volume, as measured by mercury intrusion porosimetry, of between 0.25 and 0.8 ml / g and preferably between 0.35 and 0.7 ml / g.

[0086] The mesopore volume of the catalyst prepared according to the invention, i.e. the volume contained in pores with a diameter between 2 and 50 nm (inclusive) as measured by mercury intrusion porosimetry, is between 0.1 and 0.6 ml / g and preferably between 0.2 and 0.5 ml / g.

[0087] The macropore volume of the catalyst prepared according to the invention, ie the volume contained in pores with a diameter greater than 50 nm as measured by mercury intrusion porosimetry, is between 0 and 0.4 ml / g and preferably between 0 and 0.2 ml / g.

[0088] The catalyst according to the invention generally has a mass fraction greater than 250 m 2 / g, preferably greater than 300m 2 / g, and preferably greater than 320m 2 / g specific surface area.

[0089] According to the present invention, the content of MFI zeolite in the catalyst according to the present invention is between 45% and 90% by weight, and preferably between 55% and 80% by weight, relative to the total mass of the catalyst.

[0090] The zeolite volume content of the catalyst according to the invention is advantageously greater than 350 kg / m 3 , preferably greater than 400kg / m 3 .

[0091] The TPD of the catalyst according to the invention is advantageously between 0.5 and 1.0 g / ml and preferably between 0.6 and 0.9 g / ml.

[0092] The catalyst types obtained can be used in many heterogeneous catalytic applications requiring acid functionality, in particular those for hydrocarbon conversions: for the conversion of methanol (to olefins, to gasoline, etc.), for the conversion of olefins (to olefins, to gasoline, to diesel, etc.), for various processes for converting paraffins to aromatics, alkylation processes, and processes for the dewaxing of diesel, oils, plastic pyrolysis products, biomass pyrolysis products, etc.

[0093] The present invention is illustrated by the following examples, which are in no way limiting. Example

[0094] Example 1: Preparation of Catalyst A (not of the present invention)

[0095] To prepare catalyst A, a ZSM-5MFI type zeolite having an average primary particle size of about 1 to 3.5 μm, a Si / Al atomic ratio of 22 and in the NH4 form was used. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 30 / 70. They are then introduced into a double sigma paddle kneader of the MX series. The mixture was placed in a closed tank. The peptizing agent nitric acid (HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a homogeneous and cohesive paste. After mixing for 30 minutes, the neutralizing agent ammonia (NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 40%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined at 540°C for 4 hours in moist air with a water content equal to 6% by volume.

[0096] The characteristics of the resulting catalyst are given in Table 1 below.

[0097] Example 2: Preparation of Catalyst B (Not of the Present Invention)

[0098] To prepare catalyst B, a ZSM-5MFI type zeolite having an average primary particle size of about 150 to 500 nm, a Si / Al atomic ratio of 25 and in the NH4 form was prepared. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 30 / 70. They are then introduced into a double sigma paddle kneader of the MX series. The mixture was placed in a closed jar. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of approximately 50%, this value being adjusted according to the recipe to obtain a homogeneous and cohesive paste. No neutralizing agent was added to the paste. The paste was extruded using a piston extruder through a die with a diameter of 3 mm. The extrudate thus obtained was dried (120°C in a ventilated oven in air for one night) and then calcined at 540°C for 4 hours in moist air with a water content equal to 6% by volume.

[0099] The characteristics of the resulting catalyst are given in Table 1 below.

[0100] Example 3: Preparation of Catalyst C (not of the present invention)

[0101] To prepare catalyst C, a ZSM-5MFI type zeolite having an average elementary particle size of about 150 to 500 nm, a Si / Al atomic ratio of 25 and in the NH4 form was prepared. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 30 / 70. They are then introduced into a double sigma paddle kneader of the MX series. The mixture was placed in a closed tank. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a uniform and cohesive paste. After mixing for 30 minutes, a neutralizing agent (ammonia, NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 40%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined in dry air at 540°C for 4 hours.

[0102] The characteristics of the resulting catalyst are given in Table 1 below.

[0103] Example 4: Preparation of Catalyst D (Not of the Present Invention)

[0104] To prepare catalyst D, a ZSM-5MFI type zeolite having an average primary particle size of about 1 to 2 μm, a Si / Al atomic ratio of 22 and in the NH4 form was used. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 40 / 60. They are then introduced into a double sigma paddle kneader of the MX series. The mixture was placed in a closed tank. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a homogeneous and cohesive paste. After mixing for 30 minutes, a neutralizing agent (ammonia, NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 40%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined at 540°C for 4 hours in moist air with a water content equal to 6% by volume.

[0105] The characteristics of the resulting catalyst are given in Table 1 below.

[0106] Example 5: Preparation of Catalyst E (Not of the Present Invention)

[0107] To prepare catalyst E, a ZSM-5MFI type zeolite having an average primary particle size of about 150 to 500 nm, a Si / Al atomic ratio of 25 and in the NH4 form was prepared. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a 50 / 50 mass ratio. They are then introduced into the MX series double sigma paddle kneader. The mixture was placed in a closed tank. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a uniform and cohesive paste. After mixing for 30 minutes, a neutralizing agent (ammonia, NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 40%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined in dry air at 540°C for 4 hours.

[0108] The characteristics of the resulting catalyst are given in Table 1 below.

[0109] Example 6: Preparation of Catalyst F (Present Invention)

[0110] To prepare catalyst F, a ZSM-5MFI type zeolite having an average elementary particle size of about 150 to 500 nm, a Si / Al atomic ratio of 25 and in the NH4 form was prepared. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 30 / 70. They are then introduced into the MX series double sigma paddle kneader. The mixture was placed in a closed tank. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a homogeneous and cohesive paste. After mixing for 30 minutes, a neutralizing agent (ammonia, NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 100%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined at 540°C for 4 hours in moist air with a water content equal to 6% by volume.

[0111] The characteristics of the resulting catalyst are given in Table 1 below.

[0112] Example 7: Preparation of Catalyst G (Present Invention)

[0113] To prepare catalyst G, a ZSM-5MFI type zeolite having an average primary particle size of about 150 to 500 nm, a Si / Al atomic ratio of 25 and in the NH4 form was prepared. Boehmite adhesive Molding. Boehmite and zeolite powders are dry mixed in a mass ratio of 40 / 60. They are then introduced into the MX series double sigma paddle kneader. The mixture was placed in a closed tank. A peptizing agent (nitric acid, HNO3) was added to achieve an acid content of 4%. Water was also gradually introduced to achieve an LOI of about 50%, this value being adjusted according to the recipe to obtain a homogeneous and cohesive paste. After mixing for 30 minutes, a neutralizing agent (ammonia, NH4OH) was added to the paste. The amount of neutralizing agent used was adjusted to achieve a neutralization degree of 40%. The paste was kneaded for another 15 minutes and then extruded through a die with a diameter of 3 mm using a piston extruder. The extrudate thus obtained was dried (in a ventilated oven in air at 120°C for 1 night) and then calcined at 540°C for 4 hours in moist air with a water content equal to 6% by volume.

[0114] The characteristics of the resulting catalyst are given in Table 1 below.

[0115] Example 8: Preparation of Catalyst H (Present Invention)

[0116] The solid H obtained in the form of extrudates according to Example 7 was dry impregnated with an impregnation solution prepared by mixing nickel nitrate (Ni(NO3)2.6H2O, The extrudates were prepared by dissolving nickel nitrate (>98%) in demineralized water. After dry impregnation, the extrudates were aged for 2 hours in a water-saturated atmosphere, then dried at 120°C for 12 hours, and finally calcined at 450°C for 2 hours in a stream of dry air. The amount of nickel nitrate in the impregnation solution was adjusted to obtain a nickel content equivalent to 3% by weight of NiO oxide.

[0117] The characteristics of the resulting catalyst are given in Table 1 below.

[0118] Example 9: Properties of Catalysts A to H

[0119] Table 1 below summarizes the characteristics of the synthesized catalysts A to H.

[0120]

[0121]

[0122] Table 1: Characteristics of the synthesized catalysts

[0123] The measured characteristics of the various catalysts given in Table 1 show that the solids prepared according to the present invention can achieve improvements compared to the known methods of the prior art. In particular, the combination of a neutralization step (solids F, G, H vs. B) and a steam treatment step (solids F, G, H vs. C and E) in combination with the use of elementary particles of small-sized MFI zeolites (solids F, G, H vs. A and D) allows for a higher zeolite loading per unit volume while maintaining good mechanical properties.

Claims

1. A process for preparing a catalyst in the form of extrudates, comprising an acidic MFI zeolite and a binder, and optionally a hydrogenation-active phase, the zeolite content being between 45% and 90% relative to the total mass of the catalyst, the process comprising at least the following steps: a) mixing the MFI zeolite and the binder, wherein the average size of the elementary particles of the MFI zeolite measured by scanning electron microscopy is between 110 and 800 nm, b) adding to the mixture obtained in step a) a peptizing agent selected from nitric acid and a carboxylic acid selected from acetic acid, citric acid and butyric acid, alone or as a mixture, c) adding to the mixture obtained in step b) a neutralizing agent selected from inorganic bases selected from sodium hydroxide, potassium hydroxide and ammonia, alone or as a mixture, and organic bases in solution, selected from amines and quaternary ammonium compounds, alone or as a mixture, d) shaping the mixture obtained in step c) by extrusion to obtain a solid, e) optionally drying the solid obtained in step d), f) subjecting said solid obtained in step d) or e) to a thermal treatment in the presence of steam at a temperature ranging from 400 to 1000° C. in the presence of an air stream containing from 1% to 60% by volume of water, g) Optionally, introducing one or more precursors of the hydrogenation-active phase into the solid obtained in step f).

2. The method according to claim 1, wherein the MFI zeolite is H-ZSM-5.

3. The method according to claim 1, wherein the average size of the elementary particles of the MFI zeolite measured by scanning electron microscopy is between 120 and 700 nm.

4. The method according to claim 1, wherein the average size of the elementary particles of the MFI zeolite measured by scanning electron microscopy is between 150 and 500 nm. The method according to claim 1 , wherein the MFI-type zeolite is ZSM-5.

6. The process according to claim 1, wherein the zeolite content is between 55% and 80% by weight relative to the total mass of the catalyst. The method of claim 1 , wherein the binder is alumina.

8. The method according to claim 1, wherein the peptizing agent used in step b) is nitric acid.

9. The process according to claim 1, wherein the amount of peptizing agent used in step b) is defined as the total acid content, expressed as a percentage relative to the mass of dry binder introduced in step a), and is between 0.1% and 12% by weight.

10. The method according to claim 9, wherein the amount of the peptizing agent used in step b) is between 0.1 wt% and 6 wt%.

11. The method according to claim 9, wherein the amount of the peptizing agent used in step b) is between 0.1 wt% and 4 wt%.

12. The process according to claim 1, wherein the neutralizing agent used in step c) is an inorganic base.

13. The process according to claim 12, wherein the neutralizing agent used in step c) is ammonia.

14. The method according to claim 12, wherein the neutralizing agent used in step c) is an aqueous ammonia solution (NH4OH).

15. The process according to claim 1, wherein the amount of neutralizing agent used in step c) is defined as the degree of neutralization, expressed as a molar percentage of base relative to the amount of acid introduced in step b), and is between 1 and 200%.

16. The method according to claim 15, wherein the amount of neutralizing agent used in step c) is between 10 and 100%.

17. The process according to claim 1, wherein step f) is carried out in the presence of an air stream having a water content of 1 to 50% by volume at a temperature between 450°C and 850°C and for a period of 2 to 10 hours.

18. The process of claim 1, wherein step f) is carried out in the presence of an air stream having a water content of 1 to 10% by volume at a temperature between 450°C and 850°C and for a period of 2 to 10 hours.

19. The process of claim 1, wherein, when step g) is included, the one or more precursors of the hydrogenation-active phase comprise at least one element from Group VIII and optionally at least one element from Group VIB. 20 . The method according to claim 19 , wherein the content of the Group VIII element is 0.1 to 10 wt % of oxide relative to the total mass of the catalyst. 21 . The method according to claim 19 , wherein the content of the Group VIII element is 0.5 to 8 wt % of oxide relative to the total mass of the catalyst.

22. The method according to claim 19, wherein the content of the Group VIII element is 1 to 6 wt% of oxide relative to the total mass of the catalyst.

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