CATALYTIC REFORMING CATALYST WITH OPTIMIZED ACIDITY

Abstract

The present invention relates to a catalyst for reforming comprising: - a porous support essentially comprising alumina; - platinum at a content of between 0.2 and 0.6% by mass; - at least one element from group VA chosen from antimony, bismuth and phosphorus, at a content of between 0.2 and 0.8% by mass; - at least one element from group IA chosen from lithium, sodium and potassium, at a content of between 0.004 and 0.2% by mass; - at least one element from group IIIA chosen from gallium, indium and thallium, at a content of between 0.02 and 0.6% by mass.

Description

Title of the invention: CATALYTIC REFORMING CATALYST HAVING OPTIMIZED ACIDITY Technical field

[0001] The invention relates to the field of catalysis of the conversion of paraffins and naphthenes into aromatics by means of a catalyst comprising an alumina-based support having optimized acidity.

[0002] The present invention relates to reforming catalysts used in the petroleum and petrochemical industry.

[0003] It relates more particularly to a catalyst comprising an alumina having an optimized alkali metal content.

[0004] The invention also relates to a process for preparing the catalyst and its use for the catalytic reforming reaction. Prior art

[0005] The catalytic reforming process is a process very widely used by refiners to upgrade heavy gasoline obtained by distillation. The hydrocarbons in the heavy gasoline feedstock (paraffins and naphthenes) containing approximately 6 to 12 carbon atoms per molecule are transformed during this process into aromatic hydrocarbons or, failing that, into branched paraffins. This transformation is obtained at high temperature (of the order of 500°C), at low to medium pressure (3.5.105 to 45.105 Pa) and in the presence of a catalyst. Catalytic reforming produces reformate which makes it possible to improve the octane number of petroleum cuts. The reformate is mainly formed of C5+ compounds (containing at least 5 carbon atoms). This process also produces hydrogen-rich gas, combustible gas (formed by C1-C2 compounds) and liquefied gases (formed by C3-C4 compounds).Finally, coke formation also occurs, particularly through condensation of aromatic rings, forming a solid, carbon-rich product that is deposited on the active sites of the catalyst. Reactions that produce C1-C4 compounds, also called C4- (containing at most 4 carbon atoms) and coke are detrimental to the reformate yield and the stability of the catalyst. It is important to seek to increase the selectivity of the catalysts to obtain high C5+ yields, while maintaining, if possible, the activity of said catalyst in order to operate the reaction at the lowest possible temperature and thus maximize the catalyst cycle time. The high activity of the catalyst must be combined with the greatest possible selectivity, i.e. cracking reactions leading to light products containing 1 to 4 carbon atoms (C4-) must be limited.

[0006] Reforming catalysts are porous solids in the form of extrudates, beads or grains and generally comprise pure alumina as a support, chlorine, platinum and at least one additional metal selected from the group consisting of metals from groups 7, 8, 9, 10, 13 and 14. They are bi-functional catalysts, that is to say they consist of two functions, one metallic and one acid, each of the functions having a well-defined role in the activity of the catalyst. The metallic function essentially ensures the dehydrogenation of naphthenes and paraffins and the hydrogenation of coke precursors. The acid function ensures the isomerization of naphthenes and paraffins and the cyclization of paraffins. The acid function is provided by the support itself, most often a pure halogenated alumina.The metallic function is provided by a noble metal from the platinum family and at least one additional metal, mainly tin for the continuous process (moving bed), and rhenium in the semi-regenerative process (fixed bed).

[0007] Document US6864212 discloses paraffinic feedstock reforming catalysts which comprise a gamma alumina-based support, bismuth, phosphorus, platinum, chlorine and optionally rhenium.

[0008] Document US4003852 discloses non-acidic hydrocarbon dehydrogenation catalysts which contain a porous support material with 0.01 to 2% by weight of platinum or palladium, 0.01 to 2% by weight of iridium, 0.01 to 5% by weight of tin or lead, and 0.1 to 5% by weight of an alkali or alkaline earth metal uniformly dispersed in the porous support material. The porous support is for example a gamma alumina and the alkali metal may be selected from the elements cesium, rubidium, potassium, sodium, and lithium.

[0009] Document EP0749779 describes catalysts for reforming paraffinic compounds. The catalysts comprise a mesoporous support (gamma alumina) on which the following active elements are deposited: from 0.1 to 5.0% of a noble metal, for example Pt; from 0.1 to 5.0% of a group IVA metal, for example Sn; from 0.1 to 6.0% of a group IIIA metal, for example In; from 0.1 to 10.0% of an alkali or alkaline earth metal element, for example Li; from 0.01 to 10.0% of a halogen, for example Cl; and from 0.1 to 5.0% of a group VIII metal selected from Fe, Co and Ni.

[0010] Document EP0020240 relates to reforming catalysts comprising platinum, tin and metals from group IA or IIA. It thus claims hydrocarbon hydrotreatment catalysts comprising: a refractory mineral oxide support; a halogen element present in combined form; from 0.02 to 2%, preferably from 0.10 to 0.70% by weight relative to the total weight of the catalyst of at least one metal M1 belonging to the platinum group in free or combined form; from 0.02 to 2%, preferably from 0.05 to 0.60% by weight relative to the total weight of the catalyst, of tin in free or combined form; said catalysts being characterized in that they contain, in combined form, at least one metal M2 chosen from groups IA and IIA of the periodic table of elements, in an amount such that the ratio M2 / M1 of the number of atoms of the metal M2 to the number of atoms of the metal M1 is between 0.2 and 10, preferably between 0.5 and 5.

[0011] The catalysts currently available on the market do not have sufficiently optimized acidity and lead to the production of cracking by-products.

[0012] Prior art catalysts doped with alkali metals are generally limited in activity and stability. An aim of the present invention is to provide a catalyst with improved properties in terms of selectivity while maintaining its activity and stability, which makes it possible to limit, for example, the formation of coke and thus improve the cycle time of the catalyst before its regeneration. This regeneration essentially involves a controlled combustion step of the coke and an oxychlorination step in order to redisperse the metals in the presence of chlorine or a chlorinated compound.

[0013] The applicant has surprisingly demonstrated that the presence in the catalyst of a combination: element from group VA chosen from antimony, bismuth and phosphorus / element from group IA chosen from lithium, sodium and potassium / element from group IIIA chosen from gallium, indium and thallium; makes it possible to obtain a catalyst having an optimized acidity allowing it to acquire a high selectivity towards C5+ superior to the catalysts of the prior art in processes for reforming naphtha-type feedstocks. Summary of the invention

[0014] The present invention relates to a catalyst for reforming comprising:

[0015] - a porous support essentially comprising alumina; - platinum with a content of between 0.2 and 0.6% by mass; - at least one element from group VA chosen from antimony, bismuth and phosphorus, at a content of between 0.2 and 0.8% by mass; - at least one element from group IA chosen from lithium, sodium and potassium, at a content of between 0.004 and 0.2% by mass; - at least one element from group IIIA chosen from gallium, indium and thallium, at a content of between 0.02 and 0.6% by mass.

[0016] The present invention also relates to a process for preparing the catalyst according to the invention comprising at least the following steps:

[0017] a) shaping a support essentially comprising alumina from a mixture comprising an alumina precursor;

[0018] b) depositing one or more elements on the support obtained in step a) and obtaining of a doped support, the element(s) being able to be deposited on said support in any order, simultaneously or successively, the elements being the following: - platinum, - at least one element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, - at least one element from group IIIA chosen from gallium, indium and thallium, preferably Indium, - at least one element from group IA chosen from lithium, sodium and potassium, preferably lithium or potassium,

[0019] c) drying, followed by calcination of the doped support obtained in step b) to obtain a catalyst in oxide form;

[0020] d) reduction under hydrogen of the catalyst in oxide form obtained in step c) preferably at a temperature between 100 and 600°C for a duration between 0.5 and 6 hours to obtain a reduced catalyst. DETAILED DESCRIPTION OF THE INVENTION

[0021] According to the present invention, the expression "between ... and ..." and "between .... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this is not the case and the limit values ​​are not included in the range described, such precision will be provided by the present invention.

[0022] In the sense of the present invention, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, in the sense of the present invention, a preferred pressure value range may be combined with a more preferred temperature value range.

[0023] In the following, particular embodiments of the invention may be described. They may be implemented separately or combined with each other, without limitation of combinations when this is technically feasible.

[0024] In the present application, the term "comprise" is synonymous with (means the same as) "include" and "contain", and is inclusive or open and does not exclude other elements not recited. It is understood that the term "comprise" includes the exclusive and closed term "consist".

[0025] In the present description, the term "Cx" designates hydrocarbon compounds containing x carbon atoms. The term "Cx+" designates hydrocarbon compounds containing at least x carbon atoms. The term "Cx-" designates hydrocarbon compounds containing at most x carbon atoms. The term "Cx to "Cy" denotes hydrocarbon compounds having between x and y carbon atoms.

[0026] Throughout this text, all metal and dopant contents in the catalysts are expressed in mass in non-oxide form. For a calcined catalyst, the mass content of metal or dopant in non-oxide form corresponds to the content on the catalyst itself.

[0027] Throughout this text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIIIB according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUP AC classification, and group IB according to the CAS classification corresponds to the metals of column 11 according to the new IUP AC classification.

[0028] In the following description of the invention, the term specific surface area means the BET specific surface area determined by nitrogen adsorption in accordance with ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "Journal of the American Chemical Society", 60, 309, (1938). The representative pore distribution of a mesopore population is determined by the Barrett-Joyner-Halenda (BJH) model. The nitrogen adsorption-desorption isotherm according to the BJH model obtained is described in the periodical "The Journal of American Society", 1951, 73, 373, written by EP Barrett, LG Joyner and PP Halenda.

[0029] In the present invention the terms “reforming” or “reforming” or “catalytic reforming” are used equivalently. Catalyst composition

[0030] The present invention relates to a catalyst for reforming comprising: - a porous support comprising essentially alumina; - platinum at a content of between 0.2 and 0.6%, preferably between 0.22 and 0.35% by mass; - at least one element from group VA chosen from antimony, bismuth and phosphorus, at a content of between 0.2 and 0.8%, preferably between 0.25 and 0.4% by mass; - at least one element from group IA chosen from lithium, sodium and potassium, at a content of between 0.004 and 0.2%, preferably between 0.01 and 0.1% by mass; - at least one element from group IIIA chosen from gallium, indium and thallium, at a content of between 0.02 and 0.6%, preferably between 0.03 and 0.08% by mass.

[0031] Advantageously, the porous support comprises a content of at least 98%, preferably at least 99% by mass of alumina.

[0032] Preferably the alumina of the porous support is a gamma alumina.

[0033] Advantageously, the element of group VA is phosphorus.

[0034] Advantageously, the element of group IA is lithium or potassium.

[0035] Advantageously, the element of group IIIA is indium.

[0036] In one embodiment, the alumina of the porous support is a gamma alumina, the group VA element is phosphorus, the group IA element is lithium or potassium, the group IIIA element is indium.

[0037] In one embodiment, the alumina of the porous support is a gamma alumina, the group VA element is phosphorus, the group IA element is lithium, the group IIIA element is indium.

[0038] In one embodiment, the alumina of the porous support is a gamma alumina, the group VA element is phosphorus, the group IA element is potassium, the group IIIA element is indium.

[0039] In one embodiment, the catalyst according to the invention further comprises at least one element from group VIIB chosen from manganese and rhenium, at a content of between 0.01 and 0.8%, preferably between 0.01 and 0.5% by mass.

[0040] Advantageously, the catalyst further comprises manganese and rhenium.

[0041] In one embodiment, the catalyst comprises a porous support essentially comprising gamma alumina, platinum, lithium or potassium, phosphorus, indium, manganese and / or rhenium.

[0042] In one embodiment, the catalyst comprises a porous support essentially comprising gamma alumina, platinum, lithium, phosphorus, indium, manganese and rhenium.

[0043] In one embodiment, the catalyst comprises a porous support comprising essentially gamma alumina, platinum, potassium, phosphorus, indium, manganese and rhenium.

[0044] In one embodiment, the catalyst according to the invention further comprises at least one halogen chosen from fluorine, chlorine, bromine and iodine, at a content of between 0.05 and 15%, preferably between 0.1 and 2%, preferably between 0.9 and 1.2% by mass, preferably the halogen is chlorine.

[0045] In one embodiment, the catalyst further comprises iridium at a content of between 0.05 and 0.6%, preferably between 0.2 and 0.3% by mass.

[0046] Advantageously, the catalyst has a BET surface area of ​​between 160 and 240 m2 / g, preferably between 180 and 210 m2 / g.

[0047] Advantageously, the catalyst has a pore volume with a diameter of less than 10 microns, between 0.2 and 1 cmVg, preferably between 0.4 and 0.9 cmVg.

[0048] Advantageously, the catalyst has an average mesopore diameter (pores with a diameter between 2 and 50 nm) of between 5 and 20 nm, preferably between 7 and 16 nm.

[0049] The catalyst according to the invention is advantageously in the form of particles which may be beads, extrudates, possibly polylobed (for example with three or four lobes), pellets or any other commonly used form. Preferably, the catalyst is in the form of extrudates. Preparation of the catalyst

[0050] The present invention also relates to a process for preparing the catalyst according to the invention comprising at least the following steps:

[0051] a) shaping a support essentially comprising alumina from a mixture comprising an alumina precursor;

[0052] b) depositing one or more elements on the support obtained in step a) and obtaining a doped support, the element(s) being able to be deposited on said support in any order, simultaneously or successively, the elements being the following: - platinum, - at least one element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, - at least one element from group IIIA chosen from gallium, indium and thallium, preferably Indium, - at least one element from group IA chosen from lithium, sodium and potassium, preferably lithium or potassium, - optionally at least one element from group VIIB chosen from manganese and rhenium,

[0053] c) drying, followed by calcination of the doped support obtained in step b) to obtain a catalyst in oxide form;

[0054] d) reduction under hydrogen of the catalyst in oxide form obtained in step c) preferably at a temperature between 100 and 600°C for a duration between 0.5 and 6 hours to obtain a reduced catalyst.

[0055] According to another embodiment, the process for preparing the catalyst according to the invention comprises at least the following steps:

[0056] a') incorporation of at least one element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, and / or at least one element of group IIIA chosen from gallium, indium and thallium, preferably indium, to a mixture comprising an alumina precursor;

[0057] a”) shaping of a support essentially comprising alumina from the alumina precursor obtained in step a'); or

[0058] a'”) shaping of a support essentially comprising alumina from of an alumina precursor in the presence of at least one element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, and / or at least at least one element from group IIIA chosen from gallium, indium and thallium, preferably indium,

[0059] b) depositing one or more elements on the support obtained in step a”) or a'”) and obtaining a doped support, the element(s) being able to be deposited on said support in any order, simultaneously or successively, the elements being the following: - platinum, - optionally at least one element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, - optionally at least one element from group IIIA chosen from gallium, indium and thallium, preferably indium, - at least one element from group IA chosen from lithium, sodium and potassium, preferably lithium or potassium, - optionally at least one element from group VIIB chosen from manganese and rhenium,

[0060] c) drying, followed by calcination of the doped support obtained in step b) to obtain a catalyst in oxide form;

[0061] d) reduction under hydrogen of the catalyst in oxide form obtained in step c) preferably at a temperature between 100 and 600°C for a duration between 0.5 and 6 hours to obtain a reduced catalyst.

[0062] The alumina precursor used is advantageously chosen from the group consisting of hydrargillite, bayerite, boehmite, amorphous gels, so-called transition aluminas which comprise at least one phase taken from the group comprising the rho, chi, eta, gamma, delta, kappa, theta and alpha phases. Preferably, the alumina precursor is a boehmite.

[0063] The alumina precursor can also be obtained from a mixture of an acidic source of aluminum and a basic source of aluminum so as to precipitate a boehmite-type aluminum monohydrate. The acidic source of aluminum can be, for example, chosen from at least one of the following compounds: aluminum chloride, aluminum sulfate, aluminum nitrate. The basic source of aluminum can be chosen from basic aluminum salts such as sodium aluminate, potassium aluminate. The reagents are usually used in the form of aqueous solutions. The precipitation of the aluminum hydrate is, for example, obtained by controlling the pH in the following manner: - In a first step, an aqueous solution of aluminum sulfate is added simultaneously to an aqueous solution of sodium aluminate at a pH between 6 and 10 while stirring. The mixing is carried out at a temperature kept constant throughout the duration of the addition of the solutions, this temperature is generally between 40 and 70°C. The pH is also controlled during the mixing of the two solutions, for example by the choice of flow rates and concentrations of the two solutions introduced. Stirring allows the product resulting from the reaction, i.e. the aluminum hydrate precipitate, to be in contact with the starting reagents which continue to be introduced and with the precipitate previously formed. These conditions make it possible to obtain a suspension of an alumina precursor or aluminum hydrate precipitate which is in the form of boehmite. - In a second step, the alumina precursor suspension is aged. This step is preferably carried out with stirring and at a temperature between 60 and 250°C for a period of 5 min to 24 hours. The pH during this step is adjusted to between 8.5 and 10. During this aging step, the pH is controlled by the addition of a base preferably selected from the group consisting of sodium hydroxide, potassium hydroxide, a quaternary ammonium hydroxide, ammonia, sodium aluminate and potassium aluminate. - In a third step, the aged suspension is filtered. Filtration is carried out using filtration techniques well known to those skilled in the art. A filter cake is obtained which is then washed with water. This washing step removes certain unwanted impurities and produces an alumina precursor.

[0064] Alternatively, the alumina precursor may be a commercial boehmite powder or may be obtained by hydrolysis of aluminum alcoholates. Examples of boehmite powder prepared by hydrolysis of aluminum alcoholates may be found in patents FR 1391644 or US 5,055,019. The powder obtained is shaped, for example, by kneading / extrusion and is subjected to a heat treatment step which leads to obtaining the alumina support.

[0065] According to another embodiment, the alumina precursor is prepared from a boehmite powder synthesized from an acid attack of aluminum metal shavings leading to the formation of a boehmite sol, which is spray-dried in order to obtain said alumina precursor powder. The powder is then shaped, for example by kneading / extrusion, and is subjected to a heat treatment step which leads to obtaining the alumina support.

[0066] The alumina precursor is advantageously used for the manufacture of the catalyst support. This operation consists of shaping said alumina precursor (optionally combined with an alumina precursor sol), then calcining it. The shaping can be carried out by any known method such as, for example, kneading / extrusion, oil-drop shaping, granulation, compaction, atomization. Any of the conventional support shapes, such as spheres, extruded cylinders and trilobes, quadrilobes etc. can be used.

[0067] The shaped alumina precursor is then calcined at a temperature which is generally between 500°C and 830°C, preferably between 500 and 600°C. A support is thus obtained essentially comprising alumina which is preferably in the form of gamma alumina. Drying and calcination can be carried out by any methods known to those skilled in the art.

[0068] The support obtained in step a) advantageously has a specific surface area of ​​between 160 and 300 m2 / g, preferably between 160 and 280 m2 / g, even more preferably between 180 and 220 m2 / g.

[0069] Advantageously, the volume of pores with a diameter of less than 10 microns of the support obtained in step a) is between 0.2 and 1 cmVg, preferably between 0.4 and 0.9 cm3 / g.

[0070] Advantageously, the average diameter of the mesopores (pores with a diameter between 2 and 50 nm) of the support obtained in step a) is between 5 and 20 nm, preferably between 7 and 16 nm.

[0071] Advantageously, the group VA element chosen from antimony, bismuth and phosphorus, preferably phosphorus, is deposited on the support by impregnating said support with a solution containing at least one group VA element chosen from antimony, bismuth and phosphorus, preferably phosphorus, so as to obtain a mass content of group VA element of between 0.2 and 0.8%, preferably between 0.25 and 0.4%, based on the mass of the finished catalyst.

[0072] Advantageously, to deposit on the support the desired quantity of element from group VA, said element being phosphorus, a solution of phosphorus precursor is used. The solution can be prepared by any of the methods known to those skilled in the art. The phosphorus precursor is advantageously chosen from the group comprising acids and salts containing phosphorus, for example, H3PO4, H3PO3, H3PO2, NH4H2PO4, (NH4)2HPO4, preferably H3PO4.

[0073] In one embodiment, to deposit the desired amount of Group VA element onto the support, said element being bismuth, a number of bismuth precursors may be employed, including, but not limited to, Bi(NO3)3.5H2O, BiCl3, BiOCl, BiBr3, Bi acetate, Bi citrate and various Bi alkoxides may be used, with Bi citrate being preferred. Solutions of these precursors in water, optionally in admixture with a complexing agent (to improve the solubility of bismuth), acidified aqueous solutions as well as various surfactants or organic solvent solutions may all be used.

[0074] Advantageously, the platinum is deposited on the support by impregnation of said support with a solution containing at least one platinum precursor, preferably a precursor chosen from chloroplatinic acid, ammonium chloroplatinate and tetrachloroplatinate, so as to obtain a mass content of Pt element of between 0.2 and 0.6%, preferably between 0.22 and 0.35% based on the mass of the finished catalyst.

[0075] The deposition of platinum can be carried out by conventional techniques, in particular impregnation from an aqueous or organic solution of a platinum precursor or containing a platinum salt or compound. As examples of salts or compounds which can be used, mention may be made of hexachloroplatinic acid, ammonia compounds, ammonium chloroplatinate, platinum chloride, platinum dicarbonyl dichloride and hexahydroxyplatinic acid.The ammonia compounds may be, for example, platinum II tetraamine salts of formula Pt(NH3)4X2, platinum IV halogenopentamine salts of formula (Pt(NH3)5)X3, platinum tetrahalogenodiamine salts of formula PtX4(NH3)2X, platinum complexes with halogen-polyketones and halogenated compounds of formula (Pt(acac)2X) ​​in which the element X is a halogen selected from the group consisting of chlorine, fluorine, bromine and iodine, and preferably chlorine, and the acac group represents the residue of formula C5H7O2 derived from acetylacetone. Among the organic solvents that may be used, mention may be made of paraffinic, naphthenic or aromatic hydrocarbons, and halogenated organic compounds having, for example, from 1 to 12 carbon atoms per molecule. Examples include n-heptane, methylcyclohexane, toluene and chloroform. Mixtures of solvents can also be used.

[0076] Advantageously, the group IA element is deposited on the support by impregnating said support with a solution containing at least one group IA element chosen from lithium, sodium and potassium, preferably lithium or potassium, so as to obtain a mass content of group IA element of between 0.004 and 0.2%, preferably between 0.01 and 0.1%, based on the mass of the finished catalyst.

[0077] In one embodiment, the element of group IA chosen from lithium, sodium and potassium, preferably lithium or potassium, is incorporated into the support during its shaping in step a).

[0078] In one embodiment, the group IA element may be deposited on the support by means of an aqueous solution containing a salt or a hydroxide of said element. The salt may be chosen from carbonate, sulfate, nitrate, chloride.

[0079] Optionally, the at least one element of group VIIB chosen from manganese and rhenium is deposited on the support by impregnating said support with a solution containing at least one element of group VIIB chosen from manganese and rhenium, or containing at least one precursor of said elements, so as to obtain a mass content of element of group VIIB of between 0.01 and 0.8%, preferably between 0.01 and 0.5%, based on the mass of the finished catalyst.

[0080] Advantageously, the at least one element of group IIIA chosen from gallium, indium and thallium is deposited on the support by impregnation of said support with a solution containing at least one group IIIA element selected from gallium, indium and thallium, or containing at least one precursor of one or more of these elements, so as to obtain a mass content of between 0.02 and 0.6%, preferably between 0.03 and 0.08%, based on the mass of the finished catalyst. Preferably the group IIIA element is indium, which is introduced by impregnation using, for example, an indium nitrate solution.

[0081] Alternatively, in step b), the elements can be incorporated by impregnation of a single solution containing all the desired elements or precursors of elements.

[0082] The techniques used in step b) for the incorporation of the element(s) are preferably dry impregnation, impregnation by excess (or by exchange) of solution. Washing and / or drying and / or calcination steps may optionally be carried out before each new incorporation of element.

[0083] In one embodiment, the deposition of the elements can be carried out by conventional techniques from precursor compounds such as halides, nitrates, sulfates, acetates, tartrates, citrates, carbonates, oxalates of the doping metals and amine-type complexes. Any other salt or oxide of these metals soluble in water, acids, or in another suitable solvent, is also suitable as a precursor.

[0084] In one embodiment, the deposition of the elements can be carried out using a solution of an organometallic compound of said metals in an organic solvent. The organometallic compounds are chosen from the group consisting of complexes of said promoter metal and hydrocarbyl metals such as alkyl, cycloalkyl, aryl, alkylaryl and arylalkyl metals. It is also possible to use compounds of the alcoholate type or organohalogenated compounds. Mention may in particular be made of triphenylindium in the case where the doping element is indium. The impregnation solvent may be chosen from the group consisting of paraffinic, naphthenic or aromatic hydrocarbons containing from 6 to 12 carbon atoms per molecule and halogenated organic compounds containing from 1 to 12 carbon atoms per molecule. Mention may be made, for example, of n-heptane, methylcyclohexane and chloroform. Mixtures of the solvents defined above can also be used.

[0085] In one embodiment, the group VA element selected from antimony, bismuth and phosphorus, preferably phosphorus, is incorporated into the support during its shaping. Similarly, the group IIIA element selected from indium, gallium and thallium, preferably indium, is incorporated into the support during its shaping.

[0086] According to one embodiment, the element of group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, is incorporated during the preparation of the alumina precursor before its shaping. Similarly, the group IIIA element chosen from indium, gallium and thallium, preferably indium, is incorporated during the preparation of the precursor before its shaping.

[0087] Advantageously, in step c), the drying step is carried out between 80 and 290°C, preferably between 100 and 280°C and better still between 150 and 250°C, for 15 min and 2 hours and preferably in air. As for the calcination step, it is carried out between 300 and 1000°C, and may comprise only one step at a temperature of 400 to 900°C preferably, in an atmosphere containing oxygen, and preferably in the presence of free oxygen or air.

[0088] In one embodiment, the process for preparing the catalyst according to the invention further comprises a step of depositing at least one halogenated compound, preferably chlorine. Advantageously, it can be deposited on the support at the same time as another compound, for example in cases where a halide is used as a precursor of platinum, of the element of group VA or of the element of group IA.

[0089] The halogen can also be deposited by means of impregnation with an aqueous solution of the corresponding acid, for example hydrochloric acid. A typical protocol consists of impregnating the solid so as to introduce the desired quantity of halogen. The support is advantageously kept in contact with the aqueous solution for at least 30 minutes to deposit the desired quantity of halogen.

[0090] Chlorine may be deposited on the support by means of an oxychlorination treatment. Such a treatment may for example be carried out between 350 and 550°C for two hours under a flow of air containing the desired quantity of chlorine and optionally containing water. When various precursors used in the preparation of the catalyst according to the invention do not contain halogen or contain halogen in insufficient quantity, it may be necessary to add a halogenated compound during the preparation. Any compound known to those skilled in the art may be used and deposited at any of the stages of preparation of the catalyst according to the invention. In particular, it is possible to use organic compounds such as methyl or ethyl halides, for example dichloromethane, chloroform, dichloroethane, methylchloroform or carbon tetrachloride.

[0091] Processes using the catalyst according to the invention

[0092] The present invention also relates to a process for transforming a naphtha-type feedstock obtained from either oil, biomass via a gasification process or synthesis gas via a Fischer-Tropsch process, in the presence of the catalyst according to the invention.

[0093] The present invention also relates to a method for fixed bed reforming of a hydrocarbon feedstock of naphtha type, in the presence of hydrogen with an H2 / feedstock molar ratio of between 0.2 and 8, at a temperature of between 400 and 700°C, a pressure of between 0.1 and 4 MPa, and a mass flow rate of feedstock treated per unit mass of catalyst and per hour of between 0.1 and 10 h-1, by bringing said feedstock into contact with a catalyst according to the invention.

[0094] Naphtha, alone or in a mixture with other naphthas, is the feedstock that can be treated by the process according to the invention. This feedstock is a hydrocarbon cut rich in paraffinic and naphthenic compounds and relatively poor in aromatic hydrocarbon compounds. A naphtha feedstock is, for example, derived from the atmospheric distillation of crude oil or a natural gas condensate. The process according to the invention also applies to heavy naphthas produced by a catalytic cracking (FCC), coking, hydrocracking, or steam cracking gasoline unit. These feedstocks, which are more or less rich in aromatic hydrocarbon compounds, can be used to feed a catalytic reforming unit for the production of gasoline bases or aromatic bases. Naphtha can also be obtained using a so-called Fischer Tropsch process.

[0095] The naphtha hydrocarbon feedstock may comprise n-paraffinic, naphthenic and aromatic hydrocarbons having from 5 to 12 carbon atoms per molecule. These feedstocks may have an initial boiling point of between 40°C and 70°C and a final boiling point of between 160°C and 220°C. They may also consist of a fraction or a mixture of gasoline fractions having boiling points of between 40°C and 220°C. The feedstock to be treated may thus also consist of a heavy naphtha having a boiling point of between 160°C and 200°C. EXAMPLES

[0096] Example 1 Synthesis of catalysts

[0097] The support is a gamma alumina formed by kneading-extrusion of a commercial boehmite containing less than 20 ppm by weight of elemental sulfur (detection limit by X-ray fluorescence). From this commercial boehmite, 3 types of supports are obtained containing either only phosphorus (support A), or phosphorus and indium (support B), or phosphorus and bismuth (support C). The doping is obtained by incorporating the phosphorus from phosphoric acid, the indium from indium nitrate and the bismuth from bismuth nitrate. After extrusion, the support is dried overnight at 120°C then calcined for 2 hours at 730°C.

[0098] The specific surfaces of supports A, B and C are respectively 220m2 / g, 208m2 / g and 210m2 / g.

[0099] The description of the catalyst synthesis conditions is detailed below as follows: than the composition of the different formulations.

[0100] Each catalyst is activated before testing: it is reduced under hydrogen for 2 hours at 520°C then sulfurized by a hydrogen / H2S mixture (1% vol. H2S) for 14 minutes at 520°C (flow rate 0.15L / min, under normal temperature and pressure conditions).

[0101] Preparation of catalyst 1 (comparative)

[0102] For the preparation of catalyst 1, support C is used.

[0103] 520g of support C are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.42g of Pt. The amount of hydrochloric acid is adjusted to have a mass chlorine content of 1.1% in the final catalyst. After this 3h30 contact, the impregnation solution is withdrawn and the solid is put into contact for 1h30 with a second impregnation solution containing 2.08g of rhenium introduced in the form of ammonium perrhenate. This second impregnation solution is finally withdrawn and the drained catalyst is dried overnight at 120°C in an oven then calcined for 2 h at 520°C.

[0104] Catalyst 1 contains the following mass contents of elements: - 0.250% Pt - 0.242% of Re - 1.1% Cl, -0.071% Bi - 0.294% of P

[0105] 1b / Preparation of catalyst 2 (Comparison)

[0106] For the preparation of catalyst 2, support A is used.

[0107] 520g of support A are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.41g of Pt. The amount of hydrochloric acid is adjusted to have a mass chlorine content of 1.2% in the final catalyst. After contact for 4 hours, the solution is withdrawn and the drained catalyst is dried overnight at 120°C in an oven and then calcined for 2 hours at 520°C.

[0108] Catalyst 2 contains the following mass contents of elements: - 0.239% Pt - 1.2% Cl -0.401% of P

[0109] the / Preparation of catalyst 3 (Comparison)

[0110] For the preparation of catalyst 3, support A is used.

[0111] 520g of support A are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.46g of Pt. The amount of hydrochloric acid is adjusted to have a mass chlorine content of 0.86% in the final catalyst. After this 3h30 contact, the impregnation solution is withdrawn and the solid is put into contact for 1h30 with a second impregnation solution containing 2.09g of rhenium, introduced in the form of ammonium perrhenate, 0.46 g of Li (precursor = lithium nitrate) and 1.2 g of Mn (precursor manganese nitrate). This second impregnation solution is finally withdrawn and the drained catalyst is dried overnight at 120°C in an oven then calcined for 2 h at 520°C.

[0112] Catalyst 3 contains the following mass contents of elements: -0.251% of Pt -0.251% of Re - 0.86% Cl - 0.395% of P - 0.0292% Mn - 0.0148% Li

[0113] ld / Preparation of catalyst 4 (according to the invention)

[0114] For the preparation of catalyst 4, support B is used.

[0115] 520g of support B are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.40g of Pt. The amount of hydrochloric acid is adjusted to have a mass chlorine content of 0.9% in the final catalyst. After this 3h30 contact, the first impregnation solution is withdrawn and the solid is put into contact for 1h30 with a second impregnation solution containing 1.86g of rhenium, introduced in the form of ammonium perrhenate, 0.46g of Li (precursor = lithium nitrate) and 1.04g of Mn (manganese nitrate precursor). This second impregnation solution is finally withdrawn and the drained catalyst is dried overnight at 120°C in an oven then calcined for 2h at 520°C.

[0116] Catalyst 4 contains the following mass contents of elements: - 0.240% Pt - 0.224% of Re - 0.9% Cl - 0.058% of In - 0.282% of P - 0.0259% Mn - 0.0152% Li

[0117] the / Preparation of catalyst 5 (according to the invention)

[0118] For the preparation of catalyst 5, support B is used.

[0119] 520g of support B are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.53g of Pt, The amount of hydrochloric acid is adjusted to have a mass chlorine content of 1.06% in the final catalyst. After this 3h30 contact, the first impregnation solution is withdrawn and the solid is brought into contact for 1h30 with a second impregnation solution containing 1.85g of rhenium, introduced in the form of ammonium perrhenate, 2.54g of K (precursor = potassium chloride) and 1.24 g of Mn (manganese nitrate precursor). This second impregnation solution is finally withdrawn and the drained catalyst is dried overnight at 120°C in an oven then calcined for 2 h at 520°C.

[0120] Catalyst 5 contains the following mass contents of elements: - 0.252% Pt - 0.221% of Re - 1.06% Cl - 0.058% of In - 0.282% of P - 0.0257% Mn - 0.0576% K

[0121] the / Preparation of catalyst 6 (according to the invention)

[0122] For the preparation of catalyst 6, support B is used.

[0123] 520g of support B are brought into contact with an aqueous solution of chlorinated acid hydrochloric acid containing 1.40g of Pt and 0.46g of Li (precursor = lithium nitrate). The quantity of hydrochloric acid is adjusted to have a mass chlorine content of 1.2% in the final catalyst. After this 4h contact, the impregnation solution is withdrawn and the drained catalyst is dried overnight at 120°C in an oven then calcined for 2h at 520°C.

[0124] Catalyst 6 contains the following mass contents of elements: - 0.240% Pt - 1.2% Cl - 0.058% of In - 0.282% of P - 0.0152% Li

[0125] Example 2: Catalytic tests

[0126] Catalysts 1, 3, 4 and 5 are tested for the transformation of a naphtha-type hydrocarbon feedstock from petroleum distillation, the characteristics of which are as follows:

[0127] - density at 15°: 0.760 kg / dm3

[0128] - mass content of paraffins / naphthenes / aromatics: 55 / 30 / 15%

[0129] This transformation is carried out in a pilot test unit in a crossed bed in the presence of hydrogen. Before injection of the charge, the catalysts are activated at high temperature under hydrogen for 2 hours. The test is conducted using the following operating conditions:

[0130] - total pressure: 1.5 MPa

[0131] - charge flow rate: 3.5 kg per kg of catalyst per hour

[0132] - research octane number: 102

[0133] - molar ratio of recycled hydrogen to hydrocarbon feedstock: 2.3

[0134] The performances obtained after 100 hours of operation are reported in Table 1 and expressed in relative terms with respect to the reference catalyst 1, namely the temperature necessary to reach the targeted research octane number, representative of the activity of the catalyst, and the weight yields (in % by weight) of C4- (hydrocarbons containing from 1 to 4 carbon atoms), C5+ (hydrocarbons containing at least 5 carbon atoms) and of dihydrogen which are representative of the selectivity of the catalyst.

[0135] [Tables 1] Yield (% weight) Average bed temperature (°C) Catalyst h2 C4- C5+ 1 (comparative) 2.39 13.48 84.13 508 3 (comparative) 2.46 12.74 84.80 517 4 (according to the invention) 2.49 12.35 85.16 507 5 (according to the invention) 2.51 12.17 85.32 511

[0136] It is observed that the tests carried out with catalysts 4 and 5 (which contain in particular an element from group IA being lithium or potassium as well as an element from group IIIA being indium) have improved yields towards the desired products (C5+ and H2) compared to the tests with reference catalysts 1 and 3 not comprising respectively an element from group IA or an element from group IIIA, or no element from group IIIA; the yield of C5+ being higher by more than one point. These figures therefore reflect a better selectivity of the catalysts according to the invention.

[0137] It is also observed that the average temperature of the catalytic bed during the tests carried out with catalysts 4 and 5 remained practically identical to that observed during the tests carried out with reference catalysts 1 and 3, thus showing that the activity of the catalysts according to the invention was maintained compared to the reference catalysts.

Claims

Claims

1. Catalyst for reforming comprising: - a porous support essentially comprising alumina; - platinum at a content of between 0.2 and 0.6% by mass; - at least one element from group VA chosen from antimony, bismuth and phosphorus, at a content of between 0.2 and 0.8% by mass; - at least one element from group IA chosen from lithium, sodium and potassium, at a content of between 0.004 and 0.2% by mass; - at least one element from group IIIA chosen from gallium, indium and thallium, at a content of between 0.02 and 0.6% by mass.

2. The catalyst of claim 1, wherein the group VA element is phosphorus.

3. A catalyst according to any preceding claim, wherein the Group IA element is lithium or potassium.

4. A catalyst according to any preceding claim, wherein the Group IIIA element is indium.

5. The catalyst of claim 1, wherein the alumina of the porous support is gamma alumina, the group VA element is phosphorus, the group IA element is lithium, the group IIIA element is indium.

6. The catalyst of claim 1, wherein the alumina of the porous support is gamma alumina, the group VA element is phosphorus, the group IA element is potassium, the group IIIA element is indium.

7. Catalyst according to any one of the preceding claims, in which the catalyst further comprises at least one element from group VIIB chosen from manganese and rhenium, at a content of between 0.01 and 0.8% by mass.

8. The catalyst of claim 7, wherein the catalyst comprises a porous support comprising essentially gamma alumina, platinum, lithium, phosphorus, indium, manganese and rhenium.

9. The catalyst of claim 7, wherein the catalyst comprises a porous support comprising essentially gamma alumina, platinum, potassium, phosphorus, indium, manganese and rhenium.

10. Catalyst according to any one of the preceding claims, wherein the catalyst further comprises at least one halogen chosen from fluorine, chlorine, bromine and iodine, at a content of between 0.05 and 15% by mass.

11. A catalyst according to any preceding claim, wherein the catalyst has a BET surface area of ​​between 160 and 240 m2 / g.

12. Process for preparing the catalyst according to any one of claims 1 to 11 comprising at least the following steps: a) shaping a support essentially comprising alumina from a mixture comprising an alumina precursor;b) depositing one or more elements on the support obtained in step a) and obtaining a doped support, the element(s) being able to be deposited on said support in any order, simultaneously or successively, the elements being the following: - platinum, - at least one element from group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, - at least one element from group IIIA chosen from gallium, indium and thallium, preferably indium, - at least one element from group IA chosen from lithium, sodium and potassium, preferably lithium or potassium, c) drying, followed by calcination of the doped support obtained in step b) to obtain a catalyst in oxide form; d) reduction under hydrogen of the catalyst in oxide form obtained in step c), preferably at a temperature between 100 and 600°C for a duration between 0.5 and 6 hours to obtain a reduced catalyst.;

13. A process for preparing the catalyst according to any one of claims 1 to 11 comprising at least the following steps: a') incorporation of at least one element from group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, and / or at least one element from group IIIA chosen from gallium, indium and thallium, preferably indium, into a mixture comprising an alumina precursor; a”) shaping a support essentially comprising alumina from the alumina precursor obtained in step a'); or a'”) shaping a support essentially comprising alumina from an alumina precursor in the presence of at least one element from group VA chosen from antimony, bismuth and phosphorus, preferably phosphorus, and / or at least one element from group IIIA chosen from gallium, indium and thallium, preferably indium, b) depositing one or more elements on the support obtained in step a”) or a'”) and obtaining a doped support, the element(s) being able to be deposited on said support in any order, simultaneously or successively, the elements being the following: - platinum, - at least one element from group IA chosen from lithium, sodium and potassium, preferably lithium or potassium, - optionally at least one element from group VIIB chosen from manganese and rhenium, c) drying, followed by calcination of the doped support obtained in step b) to obtain a catalyst in oxide form; d) reduction under hydrogen of the catalyst in oxide form obtained in step c) preferably at a temperature between 100 and 600°C for a duration between 0.5 and 6 hours to obtain a reduced catalyst.

14. Process for transforming a naphtha-type feedstock obtained from either oil, biomass via a gasification process or synthesis gas via a Fischer-Tropsch process, in the presence of the catalyst according to any one of claims 1 to 11.

15. Process for the fixed-bed reforming of a naphtha-type hydrocarbon feedstock, in the presence of hydrogen with an H2 / feedstock molar ratio of between 0.2 and 8, at a temperature of between 400 and 700°C, a pressure of between 0.1 and 4 MPa, and a mass flow rate of feedstock treated per unit mass of catalyst and per hour of between 0.1 and 10 h-1, by bringing said feedstock into contact with a catalyst according to any one of claims 1 to 11.