EP3870362A1

EP3870362A1 - Hydrogenation process comprising a catalyst prepared by addition of an organic compound in the gas phase

Info

Publication number: EP3870362A1
Application number: EP19786341.8A
Authority: EP
Inventors: Anne-Claire Dubreuil; Vincent Coupard; P-Louis Carrette; Florent Guillou; Bertrand Guichard
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2018-10-25
Filing date: 2019-10-15
Publication date: 2021-09-01
Also published as: US20210331145A1; FR3087787B1; CN113242766A; FR3087787A1; WO2020083714A1

Abstract

A process for hydrogenation of a polyunsaturated compound contained in a hydrocarbon feedstock in the presence of a catalyst comprising a porous support and an active phase comprising a metal of group VIII, wherein said catalyst is prepared according to the following steps: a) an organic compound containing oxygen and/or nitrogen but not comprising sulfur is added to the porous support; b) said porous support is brought into contact with a solution containing a salt that is a precursor of the active phase; c) the porous support obtained at the end of step b) is dried; characterized in that step a) is carried out before or after steps b) and c) and is carried out by placing said porous support in the presence of said organic compound under temperature, pressure and time conditions such that a fraction of said organic compound is transfer in the gaseous state to the porous support.

Description

HYDROGENATION PROCESS COMPRISING A CATALYST PREPARED BY THE ADDITION OF AN ORGANIC COMPOUND IN THE GASEOUS PHASE

Technical area

The subject of the invention is a process for the selective hydrogenation of polyunsaturated compounds in a hydrocarbon feedstock, in particular in C2-C5 steam cracking cuts and steam cracking essences, or a process for the hydrogenation of at least one aromatic or polyaromatic compound contained in a hydrocarbon feedstock allowing the transformation of aromatic compounds from petroleum or petrochemical cuts by conversion of aromatic rings into naphthenic rings. The process for selective hydrogenation or for hydrogenation of aromatics is carried out in the presence of a catalyst prepared according to a particular procedure.

State of the art

Catalysts for the selective hydrogenation of polyunsaturated compounds or for the hydrogenation of aromatic compounds are generally based on group VIII metals of the periodic table, such as nickel. The metal is in the form of nanometric metallic particles deposited on a support which can be a refractory oxide. The group VIII metal content, the possible presence of a second metallic element, the size of the metal particles and the distribution of the active phase in the support as well as the nature and porous distribution of the support are parameters which can have a importance on the performance of catalysts.

The rate of the hydrogenation reaction is governed by several criteria, such as the diffusion of the reactants on the surface of the catalyst (external diffusion limitations), the diffusion of the reactants in the porosity of the support towards the active sites (internal diffusion limitations) and the intrinsic properties of the active phase such as the size of the metal particles and the distribution of the active phase within the support.

As regards the size of the metal particles, it is generally accepted that the catalyst is more active the smaller the size of the metal particles. In addition, it is important to obtain a particle size distribution centered on the optimal value as well as a narrow distribution around this value. The most conventional way of preparing these catalysts is the impregnation of the support with an aqueous solution of a nickel precursor, generally followed by drying and calcination. Before their use in hydrogenation reactions these catalysts are generally reduced in order to obtain the active phase which is in metallic form (that is to say in the state of zero valence). The nickel-based alumina catalysts prepared by a single impregnation step generally make it possible to reach nickel contents of between 12 and 15% by weight of nickel approximately relative to the total weight of the catalyst, depending on the pore volume of the alumina used. When it is desired to prepare catalysts with a higher nickel content, several successive impregnations are often necessary to obtain the desired nickel content, followed by at least one drying step, then optionally a calcination step between each impregnation .

Furthermore, with a view to obtaining better catalytic performance, in particular better selectivity and / or activity, it is known in the prior art to use additives of the organic compound type for the preparation of metal catalysts, in particular for catalysts which have been prepared by impregnation optionally follow a maturing step and followed by a drying step. Numerous documents describe the use of different ranges of organic compounds such as nitrogen-containing organic compounds and / or oxygen-containing organic compounds. For example, application FR2984761 discloses a process for the preparation of a selective hydrogenation catalyst comprising a support and an active phase comprising a group VIII metal, said catalyst being prepared by a process comprising a step of impregnating a solution containing a group VIII metal precursor and an organic additive, more particularly an organic compound having one to three carboxylic acid functions, a step of drying the impregnated support, and a step of calcining the dried support in order to obtain the catalyst.

The processes for preparing the additive catalysts typically use an impregnation step in which the organic compound is introduced, optionally in solution in a solvent, so as to fill all the porosity of the support, whether or not it is impregnated with precursors metallic, in order to obtain a homogeneous distribution. This inevitably leads to the use of large quantities of organic compound or to diluting the organic compound in a solvent. After impregnation, a drying step is then necessary to remove the excess compound or the solvent and thus release the porosity necessary for the use of the catalyst. At the additional cost related to the excess of the compound organic or the use of a solvent is added the cost of an additional step of preparation of drying, consuming energy. During the drying step, evaporation of the solvent can also be accompanied by a partial loss of the organic compound by vaporization and therefore a loss of catalytic activity.

The Applicant has surprisingly discovered that a catalyst comprising an active phase based on at least one group VIII metal, preferably nickel, supported on an oxide matrix, prepared from a preparation process comprising at least a step of adding an organic compound to the porous support by impregnation in the gaseous phase makes it possible to obtain performance in terms of activity in selective hydrogenation of polyunsaturated compounds or in hydrogenation of aromatic compounds at least as good, or even better, than the known processes of the state of the art. Without wishing to be bound by any theory, it seems that the gaseous addition of the organic additive during the preparation of the catalyst makes it possible to obtain performance in hydrogenation in terms of activity at least as good, or even better, than known catalysts, the preparation process of which comprises a step of adding the same organic additive by liquid means (for example by dry impregnation) even though the size of the active phase particles obtained on the catalyst (measured in their forms oxide) is equivalent.

Objects of the invention

The subject of the present invention is a process for the hydrogenation of at least one polyunsaturated compound containing at least 2 carbon atoms per molecule, such as diolefins and / or acetylenics and / or aromatic or polyaromatic compounds, contained in a filler of hydrocarbons having a final boiling point less than or equal to 650 ° C, which process being carried out at a temperature between 0 and 350 ° C, at a pressure between 0.1 and 20 MPa, at a hydrogen molar ratio / (compound to be hydrogenated) between 0.1 and 1000 and at an hourly volume velocity VVH of between 0.05 and 40,000 h ¹ in the presence of a catalyst comprising a porous support and an active phase comprising at least one group VIII metal , said active phase not comprising any group VIB metal, said catalyst being prepared according to at least the following steps:

a) adding to the porous support at least one organic compound containing oxygen and / or nitrogen but not comprising sulfur; b) carrying out a step of bringing said porous support into contact with at least one solution containing at least one salt of a precursor of the phase comprising at least one group VIII metal;

c) the porous support obtained at the end of step b) is dried;

characterized in that step a) is carried out before or after steps b) and c) and is carried out by bringing said porous support and said organic compound into contact under temperature, pressure and duration conditions such as fraction of said organic compound is transferred in the gaseous state to the porous support.

In an embodiment according to the invention, step a) is carried out by placing said porous support and said organic compound in the liquid state and without physical contact simultaneously, at a temperature below the boiling temperature of said organic compound and under conditions of pressure and duration such that a fraction of said organic compound is transferred in the gaseous state to the porous support.

Advantageously, step a) is carried out by means of an addition unit of said organic compound comprising first and second compartments in communication so as to allow the passage of a gaseous fluid between the compartments, the first compartment containing the porous support and the second compartment containing the organic compound in the liquid state.

Advantageously, the unit comprises an enclosure including the first and second compartments, the two compartments being in gas communication.

Advantageously, the unit comprises two enclosures respectively forming the first and the second compartments, the two enclosures being in communication by gas.

Advantageously, step a) is carried out in the presence of a flow of a carrier gas flowing from the second compartment into the first compartment. In a second embodiment according to the invention, step a) is carried out by bringing said porous support into contact with a porous solid comprising said organic compound under conditions of temperature, pressure and duration such that a fraction of said organic compound is transferred by gas from said porous solid to said porous support. Preferably, step a) is carried out by bringing said porous support into contact without physical contact with a porous solid comprising said organic compound.

Preferably, in step a), the porous support and the porous solid comprising said organic compound are of different porosity and / or chemical nature (s).

Preferably, at the end of step a), the porous solid containing the organic compound is separated from said porous support and is returned to step a).

Advantageously, said organic compound is chosen from compounds comprising one or more chemical functions chosen from a carboxylic acid, alcohol, ester, aldehyde, ketone, ether, carbonate, amine, azo, nitrile, imine, amide, carbamate, carbamide, acid function. amine, ether, dilactone, carboxyanhydride.

In an embodiment according to the invention, the process is a process for the hydrogenation of at least one aromatic or polyaromatic compound contained in a hydrocarbon feed having a final boiling point less than or equal to 650 ° C, said process being carried out in the gas phase or in the liquid phase, at a temperature between 30 and 350 ° C, at a pressure between 0.1 and 20 MPa, at a hydrogen / hydrogen (aromatic compounds to be hydrogenated) ratio between 0.1 and 10 and at an hourly volume speed VVH of between 0.05 and 50 h ¹ .

In an embodiment according to the invention, the process is a process for the selective hydrogenation of polyunsaturated compounds contained in a hydrocarbon feedstock having a final boiling point less than or equal to 300 ° C., which process being carried out at a temperature between 0 and 300 ° C, at a pressure between 0.1 and 10 MPa, at a hydrogen / hydrogen (polyunsaturated compounds to be hydrogenated) ratio between 0.1 and 10 and at an hourly volume speed between 0, 1 and 200 h ¹ when the process is carried out in liquid phase, or at a hydrogen / (polyunsaturated compounds to be hydrogenated) molar ratio between 0.5 and 1000 and at an hourly volume speed between 100 and 40 000 h ¹ when the process is performed in the gas phase.

Brief description of the figures

FIG. 1 schematically illustrates an embodiment of step a) of the process for preparing the catalyst used in the context of the hydrogenation process according to the invention. detailed description

Definitions

By "macropores" is meant pores with an opening greater than 50 nm.

By "mesopores" is meant pores with an opening of between 2 nm and 50 nm, limits included.

By "micropores" is meant pores with an opening of less than 2 nm.

By total pore volume of the catalyst or of the support used for the preparation of the catalyst according to the invention is meant the volume measured by intrusion with a mercury porosimeter according to standard ASTM D4284-83 at a maximum pressure of 4000 bar (400 MPa), using a surface tension of 484 dyne / cm and a contact angle of 140 °. The wetting angle was taken equal to 140 ° following the recommendations of the book "Engineering techniques, treatise analysis and characterization", pages 1050-1055, written by Jean Charpin and Bernard Rasneur.

In order to obtain better accuracy, the value of the total pore volume corresponds to the value of the total pore volume measured by intrusion with a mercury porosimeter measured on the sample minus the value of the total pore volume measured by intrusion with the mercury porosimeter measured on the same sample for a pressure corresponding to 30 psi (about 0.2 MPa).

The specific surface of the catalyst or of the support used for the preparation of the catalyst according to the invention is understood to mean the specific surface B.E.T. determined by nitrogen adsorption in accordance with standard ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "The Journal of American Society", 60, 309, (1938).

The size of nickel nanoparticles is understood to mean the average diameter of the nickel crystallites measured in their oxide forms. The average diameter of the nickel crystallites in oxide form is determined by X-ray diffraction, from the width of the diffraction line located at the angle 2theta = 43 ° (that is to say according to the crystallographic direction [ 200]) using Scherrer's relation. This method, used in X-ray diffraction on powders or polycrystalline samples which relates the width at half-height of the diffraction peaks to the size of the particles, is described in detail in the reference: Appl. Cryst. (1978), 1 1, 102- 1 13 "Scherrer after sixty years: A survey and some new results in the determination of crystallite size", JI Langford and AJC Wilson. In the following, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, CRC press publisher, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification. Description of the catalyst preparation process

In general, the process for the preparation of the catalyst used in the context of the hydrogenation process according to the invention comprises at least the following steps:

a) adding on a porous support at least one organic compound containing oxygen and / or nitrogen, but not comprising sulfur;

b) carrying out a step of bringing said porous support into contact with at least one solution containing at least one salt of a precursor of the active phase comprising at least one metal from group VIII;

c) the porous support obtained at the end of step b) is dried;

characterized in that step a) is carried out:

- before or after steps b) and c); and

- By bringing said porous support and said organic compound into contact, under conditions of temperature, pressure and duration such that a fraction of said organic compound is transferred in the gaseous state to the porous support.

Steps a) to c) of the process for preparing the catalyst used in the context of the hydrogenation process according to the invention are described in more detail below.

Step a)

Any organic compound containing oxygen and / or nitrogen but not comprising sulfur which is in the liquid state at the temperature and at the pressure used in the step of adding the organic compound to the porous support can be used in the catalyst preparation process.

Preferably, said organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic acid, alcohol, ester, aldehyde, ketone, ether, carbonate, amine, azo, nitrile, imine, amide, carbamate, carbamide function, amino acid, ether, dilactone, carboxyanhydride. When said organic compound comprises at least one carboxylic function, said organic compound can be chosen from formic acid, ethanedioic acid (oxalic acid), propanedioic acid (malonic acid), pentanedioic acid (glutaric acid), hydroxyacetic acid (glycolic acid), 2-hydroxypropanoic acid (lactic acid), 2-hydroxypropanedioic acid (tartronic acid), 2-hydroxybutanedioic acid (malic acid), 2-hydroxypropane-1 acid , 2,3-tricarboxylic acid (citric acid), 2,3-dihydroxybutanedioic acid (tartaric acid), 2,2'-oxidiacetic acid (diglycolic acid), 2-oxopropanoic acid (pyruvic acid), l 4-oxopentanoic acid (levulinic acid).

When said organic compound comprises at least one alcohol function, said organic compound can be chosen from methanol, ethanol, phenol, ethylene glycol, propane-1, 3-diol, butane-1, 4-diol , pentane-1, 5-diol, hexane-1, 6-diol, glycerol, xylitol, mannitol, sorbitol, pyrocatechol, resorcinol, hydroquinol, diethylene glycol, triethylene glycol, polyethylene glycol having an average molar mass of less than 600 g / mol, glucose, mannose, fructose, sucrose, maltose, lactose, in any of their isomeric forms.

When said organic compound comprises at least one ester function, said organic compound can be chosen from a g-lactone or a d-lactone containing between 4 and 8 carbon atoms, g-butyrolactone, g-valerolactone, d-valerolactone , g- caprolactone, d-caprolactone, g-heptalactone, d-heptalactone, g-octalactone, d- octalactone, methyl methanoate, methyl acetate, methyl propanoate, butanoate methyl, methyl pentanoate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl laurate, methyl dodecanoate, ethyl acetate, ethyl propanoate, butanoate d , pentanoate, ethyl hexanoate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl oxalate, diethyl malonate, diethyl succinate, diethyl glutarate, adipate diethyl, dimethyl methyl succinate, dimethyl 3-methylglutarate, methyl glycolate, ethyl glycolate, butyl glycolate, benzyl glycolate, methyl lactate, ethyl lactate, butyl lactate , tert-butyl lactate, ethyl 3-hydroxybutyrate, ethyl mandelate, dimethyl malate, diethyl malate, diisopropyl malate, dimethyl tartrate, diethyl tartrate, tartrate diisopropyl, trimethyl citrate, triethyl citrate, ethylene carbonate, propylene carbonate, trimethylene carbonate, diethyl carbonate, diphenyl carbonate, dimethyl dicarbonate, diethyl dicarbonate, di-tert-butyl dicarbonate, in any of their isomeric forms.

When the organic compound comprises at least one amine function, said organic compound can be chosen from ethylenediamine, diaminohexane, tetramethylenediamine, hexamethylenediamine, tetramethylethylenediamine, tetraethylethylenediamine, diethylenetriamine, triethylenetetramine.

When the organic compound comprises at least one amide function, said organic compound can be chosen from formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, acetamide, N- methylacetamide, N, N-dimethylmethanamide, N, N-diethylacetamide, N, N- dimethylpropionamide, propanamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, y-lactam, caprolactam, acetylleucine, N-acetylaspartic acid, aminohippuric acid, N-acetylglutamic acid, 4-acetamidobenzoic acid, lactamide and glycolamide, urea, N-methylurea, N, N ' -dimethylurea, 1, 1 -dimethylurea, tetramethylurea according to any one of their isomeric forms.

When the organic compound comprises at least one amino acid function, said organic compound can be chosen from alanine, arginine, lysine, proline, serine, a threonine, EDTA (ethylene diamine tetraacetic acid).

When the organic compound comprises at least one ether function, said organic compound can be chosen from the group of linear ethers consisting of diethyl ether, dipropyl ether, dibutyl ether, methyl tert-butyl ether, diisopropyl ether, di -tert-butyl ether, methoxybenzene, phenyl vinyl ether, isopropyl vinyl ether and isobutyl vinyl ether, or in the group of cyclic ethers consisting of tetrahydrofuran, 1,4-dioxane, and morpholine

When the organic compound comprises a dilactone function, said organic compound can be chosen from the group of 4-membered cyclic dilactones constituted by 1, 2-dioxetanedione, or from the group of 5-membered cyclic dilactones constituted by 1, 3- dioxolane-4,5-dione, 1,5-dioxolane-2,4-dione, and 2,2-dibutyl-1,5-dioxolane-2,4-dione, or in the group of cyclic dilactones of 6 links consisting of 1, 3-dioxane-4,6-dione, 2,2-dimethyl-1, 3-dioxane-4,6-dione, 2,2,5-trimethyl-1, 3-dioxane- 4,6-dione, 1,4-dioxane-2,5-dione, 3,6-dimethyl-1,4-dioxane-2,5-dione, 3,6-diisopropyl-1,4-dioxane -2.5- dione, and 3,3-ditoluyl-6,6-diphenyl-1, 4-dioxane-2,5-dione, or in the group of 7-membered cyclic dilactones consisting of 1,2-dioxepane-3,7 -dione, 1,4-dioxepane-5,7- dione, 1,3-dioxepane-4,7-dione, and 5-hydroxy-2,2-dimethyl-1,3-dioxepane-4,7 -dione. When the organic compound has a carboxyanhydride function, said organic compound can be chosen from the group of O-carboxyanhydrides consisting of 5-methyl-1,3-dioxolane-2,4-dione and 2,5-dioxo- acid 1, 3-dioxolane-4-propanoic, or in the group of N-carboxyanhydrides consisting of 2,5-oxazolidinedione and 3,4-dimethyl-2,5-oxazolidinedione. Carboxyanhydride is understood to mean a cyclic organic compound comprising a carboxyanhydride function, that is to say a -CO-O-CO-X- or -X-CO-O-CO- chain within the cycle with -CO- corresponding to a carbonyl function and X can be an oxygen or nitrogen atom. For X = O we speak of O-carboxyanhydride and when X = N we speak of A / -carboxyanhydride.

The organic compound can be added to the porous support by two alternative embodiments described in detail below.

Variant 1

According to a first embodiment according to the invention, the hydrogenation process is carried out in the presence of a catalyst obtained by a preparation process in which step a) is carried out by bringing said porous support and said compound together organic in the liquid state, and without physical contact, at a temperature below the boiling temperature of said organic compound and under conditions of pressure and duration such that a fraction of said organic compound is transferred in the gaseous state to porous support.

In this embodiment, the method of adding the organic compound does not involve a conventional impregnation step using a solution containing a solvent in which the organic compound is diluted. Consequently, it is not necessary to carry out a step of drying the porous support in order to remove the solvent, hence a more economical process in terms of hot utility and raw material. In addition, according to this embodiment, the step of adding the organic compound is carried out at a temperature below the boiling temperature of said organic compound, hence a substantial gain from the energy point of view and in terms of safety. Indeed, for many organic compounds, such as, for example, ethylene glycol, the flash point is lower than the boiling point. There is therefore a risk of fire when working at a temperature higher than the boiling point of the organic compound. In addition, a high temperature can also lead to partial or total decomposition of the organic compound greatly reducing its effect. For example, citric acid, commonly used as an organic additive (US2009 / 0321320) decomposes at 175 ° C while its boiling point is 368 ° C at atmospheric pressure. The preparation process is also characterized in that the addition of the organic compound to the porous support is carried out without physical contact with the organic compound in the liquid state, that is to say without impregnation of the porous support by the liquid. The process is based on the principle of the existence of a vapor pressure of the organic compound which is generated by its liquid phase at a given temperature and pressure. Thus, part of the molecules of organic compound in the liquid state passes to the gaseous state (vaporization) and is then transferred (by gaseous route) to the porous support. This step a) of contacting is carried out for a sufficient time to reach the targeted content of organic compound in the porous solid which is used as a catalyst support.

In this embodiment, the step of adding the organic compound to a porous support can be carried out in a unit for adding said organic compound. The addition unit used comprises first and second compartments in communication so as to allow the passage of a gaseous fluid between the two compartments, the first compartment being able to contain the porous support and the second compartment being able to contain the organic compound in liquid form. In this embodiment, the method comprises a step a) in which the porous support and the organic compound are brought into contact in liquid form without physical contact between the porous support and the organic compound in liquid form, at a temperature below the boiling point of the organic compound and under conditions of pressure and duration such that a fraction of said organic compound is transferred by gas to the porous solid by circulation of a flow of organic compound in gaseous form from the second compartment to the first compartment, so as to ultimately provide a porous support containing the organic compound.

According to one embodiment, the addition unit comprises an enclosure including the first and second compartments, the compartments being in gas communication. For example, the compartments are arranged side by side and separated by a partition, for example substantially vertical, secured to the bottom of the enclosure and extending only over a fraction of the height of the enclosure so as to allow the sky to diffuse. gaseous of a compartment to the other. Alternatively, the compartments are arranged one above the other and are in communication so as to allow the passage of the organic compound in the gaseous state between the two compartments. Preferably the enclosure is closed.

According to another embodiment, the addition unit comprises two chambers respectively forming the first and the second compartments, the two chambers being in communication by gas, for example by means of a pipe. Preferably, the two enclosures are closed.

Preferably, the compartment intended to contain the liquid organic compound comprises means for setting in motion said liquid in order to facilitate the transfer of the organic compound in the gaseous state from one compartment to the other. According to a preferred embodiment, the two compartments comprise means for respectively moving the liquid and the porous support. Advantageously, the compartment containing the organic compound in the liquid state is equipped with internals intended to maximize the surface of the gas / liquid interface. These interns are for example porous monoliths impregnated with capillaries, falling films, linings or any other means known to the skilled person.

In a preferred embodiment, step a) is carried out in the presence of a gas (vector) flowing from the second compartment into the first compartment so as to entrain the organic molecules in the gaseous state in the compartment containing the porous support . For example, the carrier gas can be chosen from carbon dioxide, ammonia, air with controlled humidity, a rare gas such as argon, nitrogen, hydrogen, natural gas or a refrigerant gas as of the classification published by IUPAC.

According to a preferred embodiment, step a) comprises a step in which a gaseous effluent containing said organic compound is withdrawn from the first compartment and the effluent is recycled in the first and / or the second compartment.

According to another embodiment, a gaseous effluent containing said organic compound in the gaseous state is withdrawn from the first compartment, said effluent is condensed so as to recover a liquid fraction containing the organic compound in the liquid state and said fraction is recycled liquid in the second compartment.

Step a) is preferably carried out at an absolute pressure of between 0.1 and 1 MPa. As specified above, the temperature of step a) is fixed at a lower temperature at the boiling point of the organic compound. The temperature of step a) is generally less than 200 ° C, preferably between 10 ° C and 150 ° C, more preferably between 25 ° C and 120 ° C.

Variant 2

According to a second embodiment according to the invention, the hydrogenation process is carried out in the presence of a catalyst obtained by a preparation process in which step a) is carried out by bringing together said porous support with a solid porous (also called here “carrier solid”) comprising said organic compound under conditions of temperature, pressure and duration such that a fraction of said organic compound is transferred by gas from said solid carrier to said porous support.

The objective of bringing the porous support into contact with the carrier solid comprising the organic compound is to allow a gaseous transfer of part of the organic compound contained in the carrier solid to the porous support. This step is based on the principle of the existence of a vapor pressure of the organic compound at a given temperature and pressure. Thus, part of the organic compound molecules of the solid vector comprising the organic compound passes in gaseous form (vaporization) and is then transferred (by gaseous route) to the porous support. According to this embodiment, the porous solid (“carrier solid”) acts as a source of organic compound to enrich the porous support with organic compound, which preferably does not initially comprise an organic compound. This embodiment is therefore different from a simple maturation step as conventionally encountered in the prior art. Indeed, the diffusion of the organic compound from the carrier solid to the porous support is carried out in condensed form inside each grain of the solid (in an inter-granular manner), unlike a conventional maturation for which the diffusion of the organic compound is performed intragranularly (inside each grain of the support). Such a definition of maturation is illustrated in the thesis of Jonathan Moreau; "Rationalization of the impregnation step of catalysts based on molybdenum heteropolyanions supported on alumina"; page 56; Claude Bernard University - Lyon I, 2012.

In addition, the use of such a contacting step, ie by gas transfer, between the porous solid comprising the organic compound and the porous support can save a drying step which would conventionally take place after an impregnation step. organic compound diluted in a solvent on the porous support (monitoring optionally a maturation step) in order to remove the solvent used. In fact, in this embodiment, the porous solid (“carrier solid”) comprising the organic compound is obtained by impregnation with the organic compound in the liquid state. Unlike the prior art, the organic compound is not diluted in a solvent. An advantage of this embodiment compared to the methods of the prior art therefore lies in the absence of a drying step which is conventionally used to remove the solvent after the impregnation step and therefore to be less energy-consuming by compared to conventional processes. This absence of a drying step can make it possible to avoid possible losses of organic compound by vaporization or even by degradation.

The volume of organic compound used is strictly less than the total volume of the accessible porosity of the porous solid and of the porous support used in step a) and is fixed relative to the amount of organic compound targeted on the porous solid at the end of step a). Another advantage of this embodiment is therefore the use of a smaller amount of organic compound compared to the case of the prior art where, in the absence of solvent, all the porosity should be filled with organic compound.

The mass ratio (porous solid comprising the organic compound) / (porous support) is a function of the porous distribution of the porous solid and the porous support and of the objective in terms of the quantity of organic compound targeted on the porous support. This mass ratio is generally less than or equal to 10, preferably less than 2 and even more preferably between 0.05 and 1, limits included.

In this embodiment, step a) is carried out under conditions of temperature, pressure and duration so as to achieve equilibration of the amount of organic compound on the porous solid (“carrier solid”) and the porous support. . The term "balancing" means the fact that at the end of step a) at least 50% by weight of the porous solid and the porous support have an amount of said organic compound equal to more or less 50% of the targeted quantity, preferably at least 80% by weight of the porous solid and the porous support have an amount of said organic compound equal to more or less 40% of the targeted quantity and even more preferably at least 90% by weight of the porous solid and of the porous support have an amount of said organic compound equal to plus or minus 20% of the targeted amount.

By way of nonlimiting example, in the case where the aim is the preparation of a porous support comprising 5% by weight of organic compound, it is possible to bring together in the same amount a porous solid containing 10% by weight of organic compound with the porous support free of said organic compound. It will be considered in this case that equilibration is achieved when at least 50% by weight of the porous solid and the porous support have an amount of said organic compound which corresponds to a content of between 2.5 and 7.5% by weight, preferably when at least 80% by weight of the porous solid and the porous support have an amount of said organic compound which corresponds to a content which is between 3 and 7% by weight, and even more preferably, when at least 90% by weight of the solid porous and porous support have an amount of said organic compound which corresponds to a content between 4 and 6% by weight.

The determination of these contents can be done by a statistically representative sampling for which the samples can be characterized for example by assaying carbon and / or possible heteroatoms contained in the organic compound or by thermogravimetry coupled to an analyzer, for example a spectrometer mass, or an infrared spectrometer and thus determine the respective contents of organic compounds.

Step a) is preferably carried out under controlled temperature and pressure conditions and so that the temperature is lower than the boiling temperature of said organic compound to be transferred by gas.

Preferably, the processing temperature is less than 150 ° C. and the absolute pressure is generally between 0.1 and 1 MPa, preferably between 0.1 and 0.5 MPa and more preferably between 0, 1 and 0.2 MPa. It is thus possible to operate the step of bringing into presence in an open or closed enclosure, possibly with a control of the composition of the gas present in the enclosure.

When the step of bringing the porous solid and the porous support together takes place in an open enclosure, it will be ensured that the entrainment of the organic compound outside the enclosure is limited as much as possible. Alternatively, the step of bringing the porous solid and the porous support into contact can be carried out in a closed enclosure, for example in a container for storing or transporting the solid which is impermeable to gas exchange with the external environment. In this embodiment, the contacting step can be carried out by controlling the composition of the gas making up the atmosphere by the introduction of one or more gaseous compounds and optionally with a controlled hygrometry. By way of nonlimiting example, the gaseous compound can be carbon dioxide, ammonia, air with hygrometry controlled gas, a rare gas such as argon, nitrogen, hydrogen, natural gas or a refrigerant gas under the classification published by IUPAC. According to an advantageous embodiment, the step of bringing into contact under a controlled gaseous atmosphere implements a forced circulation of the gas in the enclosure. In one embodiment of this alternative embodiment, the step of bringing the porous solid and the porous support into contact is carried out without physical contact, in an enclosure equipped with compartments capable of respectively containing the porous solid (“carrier solid”) and the porous support, the compartments being in communication so as to allow the passage of the organic compound in the gaseous state between the two compartments. It is advantageous to circulate a gas flow first through the compartment containing the porous solid comprising the organic compound and then through the compartment containing the porous support.

Preferably, the porous solid (“carrier solid”) is different in nature from the porous solid (serving as catalyst support), that is to say that the porous solid has at least one physical characteristic which discriminates against porous support to allow for example their subsequent separation. For example and without limitation, this physical characteristic can be:

- the particle size of the solid: the separation can be carried out on a sieve or by cyclone;

- magnetism: the separation is done by the application of a magnetic field;

- the density of the solid: in conjunction or not with the size of the particles, this difference in density can for example be used for separation by elutriation or by cyclone;

- the dielectric constant: the separation is done by the application of an electrostatic field.

Furthermore, said porous support and said porous solid containing the organic compound can advantageously be of different porosity and / or chemical nature (s). Indeed, the porous solid can be of chemical composition adapted to disadvantage the adsorption of the compound to be impregnated compared to the adsorption of the compound to be impregnated on the porous support. A similar effect can be obtained by adapting the porous structure of the porous solid so that it has an average opening of its pores which is greater than that of the porous support so as to promote the transfer of the organic compound onto the porous support, particularly in the case of capillary condensation. An embodiment of step a) of bringing the organic compound and the porous support into contact is shown diagrammatically in FIG. 1. This embodiment according to the invention corresponds to the case where the porous solid containing the organic compound serves as a reservoir as an organic compound for the porous support. As indicated in FIG. 1, a porous solid called "vector" 1 is impregnated in an impregnation unit 2 with a liquid organic compound supplied by line 3. The vector solid 4 comprising the organic compound is transferred to unit d addition 5 in which the said solid vector is brought into contact with the porous support brought by the line 6. At the end of the step of bringing the porous solid into contact with the porous support, the unit is withdrawn from the line 7, a mixture of porous support and porous solid (solid vector) each containing said organic compound. The mixture of solids (porous support and porous solid) is then sent to a separation unit 8 which performs physical separation of the solids (porous solid and porous support). Thanks to the implementation of the separation, two streams of solids are obtained, namely the porous solid 9 containing the organic compound and the porous support 10 also containing the organic compound. In accordance with this embodiment, the porous solid still containing the organic compound 9 is recycled to the unit for introducing the liquid organic compound for later use.

Step b) of bringing said porous support into contact with at least one solution containing at least one precursor salt of the phase comprising at least one group VIII metal can be carried out by impregnation, dry or in excess, according to methods well known to those skilled in the art. Said step b) is preferably carried out by bringing the porous support into contact with at least one aqueous or organic solution (for example methanol or ethanol or phenol or acetone or toluene or dimethyl sulfoxide (DMSO)) or well constituted by a mixture of water and at least one organic solvent, containing at least one precursor of the active phase comprising at least one metal from group VIII at least partially in the dissolved state, or alternatively contact of a precursor of the active phase with at least one colloidal solution of at least one group VIII metal precursor, in oxidized form (nanoparticles of oxides, oxy (hydroxide) or nickel hydroxide) or in reduced form (metallic nanoparticles of group VIII metal in the reduced state). Preferably, the solution is aqueous. The pH of this solution can be modified by the optional addition of an acid or a base. According to another preferred variant, the aqueous solution may contain ammonia or ammonium NH ₄ ⁺ ions. Preferably, said step b) is carried out by dry impregnation, which consists in bringing the porous support into contact with at least one solution, containing at least one precursor of the active phase comprising at least one group VIII metal, the volume of the solution is between 0.25 and 1.5 times the pore volume of the support of the catalyst precursor to be impregnated.

Preferably, the group VIII metal is chosen from nickel, palladium or platinum. More preferably, the group VIII metal is nickel.

When the precursor of the active phase is introduced in aqueous solution and when the group VIII metal is nickel, a nickel precursor is advantageously used in the form of nitrate, carbonate, chloride, sulphate, hydroxide, hydroxycarbonate, formate, acetate, oxalate, complexes formed with acetylacetonates, or tetrammine or hexammine complexes, or any other inorganic derivative soluble in aqueous solution, which is brought into contact with said catalyst precursor. Advantageously used as nickel precursor, nickel nitrate, nickel carbonate, nickel chloride, nickel hydroxide, nickel hydroxycarbonate. Very preferably, the nickel precursor is nickel nitrate, nickel carbonate or nickel hydroxide.

The nickel content is between 1 and 65% by weight of said element relative to the total mass of the catalyst, preferably between 5 and 55% by weight, even more preferably between 8 and 40% by weight, and particularly preferred between 12 and 35% by weight. The Ni content is measured by X-ray fluorescence.

When it is desired to use the catalyst according to the invention in a selective hydrogenation reaction of polyunsaturated molecules such as diolefins, acetylenics or alkenylaromatics, the nickel content is advantageously between 1 and 35% by weight, preferably between 5 and 30% by weight, and more preferably between 8 and 25% by weight, and even more preferably between 12 and 23% by weight of said element relative to the total mass of the catalyst.

When it is desired to use the catalyst according to the invention in an aromatic hydrogenation reaction, the nickel content is advantageously between 8 and 65% by weight, preferably between 12 and 55% by weight, even more preferably between 15 and 40% by weight, and more preferably between 18 and 35% by weight of said element relative to the total mass of the catalyst. Advantageously, the molar ratio between said organic compound introduced in step a) and the group VIII metal introduced in step b) is between 0.01 and 5.0 mol / mol, preferably between 0.05 and 2.0 mol / mol, more preferably between 0.1 and 1.5 mol / mol and even more preferably between 0.3 and 1.2 mol / mol, relative to the element of the group

Step c) Drying

The drying step c) is carried out at a temperature below 250 ° C, preferably above 15 ° C and below 250 ° C, more preferably between 30 and 220 ° C, even more preferably between 50 and 200 ° C , and even more preferably between 70 and 180 ° C, for a period typically between 10 minutes and 24 hours. Longer durations are not excluded, but do not necessarily bring improvement.

The drying step can be carried out by any technique known to those skilled in the art. It is advantageously carried out under an inert atmosphere or under an atmosphere containing oxygen or under a mixture of inert gas and oxygen. It is advantageously carried out at atmospheric pressure or at reduced pressure. Preferably, this step is carried out at atmospheric pressure and in the presence of air or nitrogen.

Step d) Calcination (optional)

Optionally, at the end of the sequence of steps a), b) and c), and indifferently according to the order of sequence of these steps (as described above), a step d) of calcination is carried out. at a temperature between 250 ° C and 1000 ° C, preferably between 250 ° C and 750 ° C, under an inert atmosphere or under an atmosphere containing oxygen. The duration of this heat treatment is generally between 15 minutes and 10 hours. Longer durations are not excluded, but do not necessarily bring improvement. After this treatment, the nickel in the active phase is thus in oxide form and the catalyst no longer contains or has very little organic compound introduced during its synthesis. However, the introduction of the organic compound during its preparation has made it possible to increase the dispersion of the active phase thus leading to a more active and / or more selective catalyst. a reducing qaz

Prior to the use of the catalyst in the catalytic reactor and the implementation of a hydrogenation process, at least one step of reducing treatment is advantageously carried out e) in the presence of a reducing gas after the sequence of steps a ), b) and c), optionally d), and indifferently according to the sequence of these steps (as described above), so as to obtain a catalyst comprising the metal of group VIII at least partially in the form metallic.

This treatment makes it possible to activate said catalyst and to form metallic particles, in particular nickel in the zero-value state. Said reducing treatment can be carried out in situ or ex situ, that is to say after or before the loading of the catalyst into the hydrogenation reactor. Said step e) of reduction can be implemented on the catalyst having been subjected or not to step f) of passivation, described below.

The reducing gas is preferably hydrogen. Hydrogen can be used pure or as a mixture (for example a hydrogen / nitrogen, hydrogen / argon, hydrogen / methane mixture). In the case where hydrogen is used as a mixture, all the proportions are possible.

Said reducing treatment is carried out at a temperature between 120 and 500 ° C., preferably between 150 and 450 ° C. When the catalyst does not undergo passivation, or undergoes a reduction treatment before passivation, the reduction treatment is carried out at a temperature between 350 and 500 ° C., preferably between 350 and 450 ° C. When the catalyst has previously been passivated, the reducing treatment is generally carried out at a temperature between 120 and 350 ° C, preferably between 150 and 350 ° C. The duration of the reducing treatment is generally between 2 and 40 hours, preferably between 3 and 30 hours. The temperature rise to the desired reduction temperature is generally slow, for example fixed between 0.1 and 10 ° C / min, preferably between 0.3 and 7 ° C / min.

The hydrogen flow rate, expressed in L / hour / gram of catalyst is between 0.1 and 100 L / hour / gram of catalyst, preferably between 0.5 and 10 L / hour / gram of catalyst, again more preferred between 0.7 and 5 L / hour / gram of catalyst. Step f) Passivation (optional)

Prior to its use in the catalytic reactor, the catalyst according to the invention can optionally undergo a passivation step (step f) with a sulfur-containing or oxygenated compound or with C0 ₂ before or after the reducing treatment step e) . This passivation step can be carried out ex-situ or in-situ. The passivation step is carried out by implementing methods known to those skilled in the art.

The sulfur passivation stage makes it possible to improve the selectivity of the catalysts and to avoid thermal runaway during the start-up of new catalysts (“run away” according to English terminology). The passivation generally consists in irreversibly poisoning the sulfur compound with the most virulent active sites of nickel which exist on the new catalyst and therefore in attenuating the activity of the catalyst in favor of its selectivity. The passivation step is carried out by the implementation of methods known to those skilled in the art and in particular, by way of example by the implementation of one of the methods described in patent documents EP0466567, US5153163, FR2676184, W02004 / 098774, EP0707890. The sulfur compound is for example chosen from the following compounds: thiophene, thiophane, alkylmonosulfides such as dimethylsulfide, diethylsulfide, dipropylsulfide and propylmethylsulfide or also an organic disulfide of formula HO-RrS-S-FVOH such as di-thio-di-ethanol with the formula HO-C2H4-SS-C2H4-OH (often called DEODS). The sulfur content is generally between 0.1 and 2% by weight of said element relative to the mass of the catalyst.

The passivation step with an oxygenated compound or with C0 ₂ is generally carried out after a reduction treatment beforehand at high temperature, generally between 350 and 500 ° C., and makes it possible to preserve the metallic phase of the catalyst in the presence of air. . A second reducing treatment at a lower temperature, generally between 120 and 350 ° C., is then generally carried out. The oxygenated compound is generally air or any other flow containing oxygen.

Catalyst characteristics

The catalyst obtained by the preparation process comprises a porous support and an active phase comprising, preferably consisting of, at least one metal from group VIII, preferably nickel, palladium or platinum, more preferably nickel, said active phase not containing group VIB metal. In particular, it does not include molybdenum or tungsten. When the metal is nickel, the nickel content being between 1 and 65% by weight of said element relative to the total weight of the catalyst, preferably between 5 and 55% by weight, even more preferably between 8 and 40 % by weight, and particularly preferably between 12 and 35% by weight. When it is desired to use the catalyst according to the invention in a selective hydrogenation reaction of polyunsaturated molecules such as diolefins, acetylenics or alkenylaromatics, the nickel content is advantageously between 1 and 35% by weight, preferably between between 5 and 30% by weight, and more preferably between 8 and 25% by weight, and even more preferably between 12 and 23% by weight of said element relative to the total mass of the catalyst.

When it is desired to use the catalyst according to the invention in an aromatic hydrogenation reaction, the nickel content is advantageously between 8 and 65% by weight, preferably between 12 and 55% by weight, even more preferred between 15 and 40% by weight, and more preferably between 18 and 35% by weight of said element relative to the total mass of the catalyst.

The active phase being in the form of nickel particles having a diameter less than or equal to 18 nm, said catalyst comprising a total pore volume measured by mercury porosimetry of between 0.01 and 1.0 ml / g, a mesoporous volume measured by mercury porosimetry greater than 0.01 mL / g, a macroporous volume measured by mercury porosimetry less than or equal to 0.6 ml / g, a mesoporous volume median diameter between 3 and 25 nm, a macroporous median diameter by volume between 50 and 1000 nm, and an SBET specific surface between 25 and 350 m ² / g

The size of the nickel particles in the catalyst according to the invention is less than 18 nm, preferably less than 15 nm, more preferably between 0.5 and 12 nm, more preferably between 1.5 and 8.0 nm .

The porous support on which said active phase is deposited comprises alumina (Al ₂ 0 ₃ ). Preferably, the alumina present in said support is a transition alumina such as a gamma, delta, theta, chi, rho or eta alumina, alone or as a mixture. More preferably, the alumina is a transition gamma, delta or theta alumina, alone or as a mixture.

In a second alternative embodiment, the alumina present in said support is an alpha alumina. The support can comprise another oxide different from alumina, such as silica (Si0 ₂ ), titanium dioxide (Ti0 ₂ ), cerine (Ce0 ₂ ), zirconia (Zr0 ₂ ) or P ₂ 0 ₅ . The support can be a silica-alumina. Very preferably, said support consists solely of alumina.

Said catalyst is generally presented in all the forms known to those skilled in the art, for example in the form of balls (generally having a diameter between 1 and 8 mm), extrudates, tablets, hollow cylinders. Preferably, it consists of extrudates with a diameter generally between 0.5 and 10 mm, preferably between 0.8 and 3.2 mm and very preferably between 1.0 and 2.5 mm and of average length. between 0.5 and 20 mm. The term “mean diameter” of the extrudates means the mean diameter of the circle circumscribed in the cross section of these extrudates. The catalyst can advantageously be presented in the form of cylindrical, multilobed, trilobed or quadrilobed extrudates. Preferably its shape will be three-lobed or four-lobed. The shape of the lobes can be adjusted according to all the methods known from the prior art.

The pore volume of the support is generally between 0.1 cm ³ / g and 1.5 cm ³ / g, preferably between 0.5 cm ³ / g and 1.0 cm ³ / g. The specific surface of the support is generally greater than or equal to 5 m ² / g, preferably greater than or equal to 30 m ² / g, more preferably between 40 m ² / g and 500 m ² / g, and even more preferably included between 50 m ² / g and 400 m ² / g.

When it is desired to use the catalyst according to the invention in a selective hydrogenation reaction of polyunsaturated molecules such as diolefins, acetylenics or alkenylaromatics, the specific surface of the support is advantageously between 40 and 250 m ² / g, preferably between 50 and 200 m ² / g.

When it is desired to use the catalyst according to the invention in an aromatic hydrogenation reaction, the specific surface of the support is advantageously between 60 and 500 m ² / g, preferably between 100 and 400 m ² / g .

Description of the process for the selective hydrogenation of polyunsaturated compounds

The present invention also relates to a process for the selective hydrogenation of polyunsaturated compounds containing at least 2 carbon atoms per molecule, such as diolefins and / or acetylenics and / or alkenylaromatics, also called styrenics, contained in a charge of hydrocarbons having a final boiling point less than or equal to 300 ° C, which process being carried out at a temperature between 0 and 300 ° C, at a pressure between 0.1 and 10 MPa, at a hydrogen / (polyunsaturated compounds to be hydrogenated) molar ratio between 0.1 and 10 and at an hourly volume speed between 0.1 and 200 h ¹ when the process is carried out in liquid phase, or at a hydrogen / hydrogen (polyunsaturated compounds to be hydrogenated) ratio between 0.5 and 1000 and at an hourly volume speed between 100 and 40,000 h ¹ when the process is carried out in the gas phase, in the presence of a catalyst obtained by the preparation process as described above in the description.

Monounsaturated organic compounds such as ethylene and propylene, are the source of the manufacture of polymers, plastics and other value-added chemicals. These compounds are obtained from natural gas, naphtha or diesel which have been treated by steam cracking or catalytic cracking processes. These processes are operated at high temperature and produce, in addition to the desired monounsaturated compounds, polyunsaturated organic compounds such as acetylene, propadiene and methylacetylene (or propyne), 1 -2-butadiene and 1 -3 - butadiene, vinylacetylene and ethylacetylene, and other polyunsaturated compounds whose boiling point corresponds to the C5 + cut (hydrocarbon compounds having at least 5 carbon atoms), in particular diolefinic or styrenic or indene compounds. These polyunsaturated compounds are very reactive and lead to parasitic reactions in the polymerization units. It is therefore necessary to eliminate them before adding value to these cuts.

Selective hydrogenation is the main treatment developed to specifically remove unwanted polyunsaturated compounds from these hydrocarbon feedstocks. It allows the conversion of polyunsaturated compounds to the corresponding alkenes or aromatics while avoiding their complete saturation and therefore the formation of the corresponding alkanes or naphthenes. In the case of steam cracking essences used as a filler, selective hydrogenation also makes it possible to selectively hydrogenate alkenylaromatics to aromatics, avoiding the hydrogenation of aromatic rings.

The hydrocarbon feedstock treated in the selective hydrogenation process has a final boiling point less than or equal to 300 ° C and contains at least 2 carbon atoms per molecule and comprises at least one polyunsaturated compound. The term “polyunsaturated compounds” means compounds comprising at least one acetylenic function and / or at least one diene function and / or at least one alkenylaromatic function. More particularly, the charge is selected from the group consisting of a C2 steam cracking cut, a C2-C3 steam cracking cut, a C3 steam cracking cut, a C4 steam cracking cut, a C5 steam cracking cut and a gas cracking essence also called pyrolysis essence or C5 + cut.

The C2 steam cracking section, advantageously used for the implementation of the selective hydrogenation process according to the invention, has for example the following composition: between 40 and 95% by weight of ethylene, of the order of 0.1 to 5% by weight of acetylene, the remainder being essentially ethane and methane. In some C2 steam cracking cuts, between 0.1 and 1% by weight of C3 compounds may also be present.

The steam cracking cut C3, advantageously used for the implementation of the selective hydrogenation process according to the invention, has for example the following average composition: of the order of 90% by weight of propylene, of the order of 1 to 8% by weight of propadiene and methylacetylene, the rest being essentially propane. In certain C3 sections, between 0.1 and 2% by weight of C2 compounds and C4 compounds may also be present.

A C2 - C3 cut can also be advantageously used for the implementation of the selective hydrogenation process according to the invention. It has for example the following composition: of the order of 0.1 to 5% by weight of acetylene, of the order of 0.1 to 3% by weight of propadiene and of methylacetylene, of the order of 30% by weight ethylene, of the order of 5% by weight of propylene, the remainder being essentially methane, ethane and propane. This charge can also contain between 0.1 and 2% by weight of C4 compounds.

The C4 steam cracking cut, advantageously used for the implementation of the selective hydrogenation process according to the invention, has for example the following average mass composition: 1% by weight of butane, 46.5% by weight of butene, 51% by weight of butadiene, 1.3% by weight of vinyl acetylene and 0.2% by weight of butyne. In some C4 sections, between 0.1 and 2% by weight of C3 compounds and C5 compounds may also be present.

The C5 steam cracking section, advantageously used for the implementation of the selective hydrogenation process according to the invention, has for example the following composition: 21% by weight of pentanes, 45% by weight of pentenes, 34% by weight of pentadienes.

The steam cracking gasoline or pyrolysis gasoline, advantageously used for the implementation of the selective hydrogenation process according to the invention, corresponds to a hydrocarbon fraction whose boiling point is generally between 0 and 300 ° C., preferably between 10 and 250 ° C. The polyunsaturated hydrocarbons to be hydrogenated present in said essence of steam cracking are in particular diolefinic compounds (butadiene, isoprene, cyclopentadiene ...), styrene compounds (styrene, alpha-methylstyrene ...) and indene compounds (indene ... ). The essence of steam cracking generally comprises the C5-C12 cut with traces of C3, C4, C13, C14, C15 (for example between 0.1 and 3% by weight for each of these cuts). For example, a charge formed from pyrolysis gasoline generally has the following composition: 5 to 30% by weight of saturated compounds (paraffins and naphthenes), 40 to 80% by weight of aromatic compounds, 5 to 20% by weight of mono-olefins, 5 to 40% by weight of diolefins, 1 to 20% by weight of alkenylaromatic compounds, all of the compounds forming 100%. It also contains from 0 to 1000 ppm by weight of sulfur, preferably from 0 to 500 ppm by weight of sulfur.

Preferably, the charge of polyunsaturated hydrocarbons treated in accordance with the selective hydrogenation process according to the invention is a C2 steam cracking cut, or a C2-C3 steam cracking cut, or a steam cracked gasoline.

The selective hydrogenation process according to the invention aims to eliminate said polyunsaturated hydrocarbons present in said charge to be hydrogenated without hydrogenating monounsaturated hydrocarbons. For example, when said charge is a C2 cut, the selective hydrogenation process aims to selectively hydrogenate acetylene. When said charge is a C3 cut, the selective hydrogenation process aims to selectively hydrogenate propadiene and methylacetylene. In the case of a C4 cut, the aim is to eliminate butadiene, vinyl acetylene (VAC) and butyne, in the case of a C5 cut, the aim is to eliminate the pentadienes. When said charge is a steam cracking essence, the selective hydrogenation process aims to selectively hydrogenate said polyunsaturated hydrocarbons present in said charge to be treated so that the diolefinic compounds are partially hydrogenated to mono-olefins and that the styrenic and indene compounds are partially hydrogenated to the corresponding aromatic compounds, avoiding the hydrogenation of the aromatic rings.

The technological implementation of the selective hydrogenation process is for example carried out by injection, in upward or downward flow, of the charge of polyunsaturated hydrocarbons and hydrogen in at least one fixed bed reactor. Said reactor can be of the isothermal type or of the adiabatic type. An adiabatic reactor is preferred. The charge of polyunsaturated hydrocarbons can advantageously be diluted by one or more re-injections) of the effluent, coming from said reactor where the hydrogenation reaction takes place selective, at various points of the reactor, located between the inlet and the outlet of the reactor in order to limit the temperature gradient in the reactor. The technological implementation of the selective hydrogenation process according to the invention can also be advantageously carried out by the implantation of at least said supported catalyst in a reactive distillation column or in reactors - exchangers or in a slurry type reactor. . The hydrogen flow can be introduced at the same time as the feed to be hydrogenated and / or at one or more different points of the reactor.

The selective hydrogenation of cuts C2, C2-C3, C3, C4, C5 and C5 + of steam cracking can be carried out in gas phase or in liquid phase, preferably in liquid phase for cuts C3, C4, C5 and C5 + and in phase gas for cuts C2 and C2-C3. A liquid phase reaction lowers the energy cost and increases the catalyst cycle time.

In general, the selective hydrogenation of a hydrocarbon feed containing polyunsaturated compounds containing at least 2 carbon atoms per molecule and having a final boiling point less than or equal to 300 ° C is carried out at a temperature between 0 and 300 ° C, at a pressure between 0.1 and 10 MPa, at a hydrogen / molar ratio (polyunsaturated compounds to be hydrogenated) between 0.1 and 10 and at an hourly volume velocity VVH (defined as the ratio of the charge flow rate to the volume of the catalyst) of between 0.1 and 200 h ¹ for a process carried out in the liquid phase, or at a hydrogen / hydrogen (polyunsaturated compounds to be hydrogenated) ratio between 0.5 and 1000 and at an hourly volume speed VVH of between 100 and 40,000 h ¹ for a process carried out in the gas phase.

In an embodiment according to the invention, when a selective hydrogenation process is carried out in which the filler is a steam cracking essence comprising polyunsaturated compounds, the molar ratio (hydrogen) / (polyunsaturated compounds to be hydrogenated) is generally understood between 0.5 and 10, preferably between 0.7 and 5.0 and even more preferably between 1.0 and 2.0, the temperature is between 0 and 200 ° C, preferably between 20 and 200 ° C and even more preferably between 30 and 180 ° C., the hourly space velocity (VVH) is generally between 0.5 and 100 h ¹ , preferably between 1 and 50 h ¹ and the pressure is generally between 0, 3 and 8.0 MPa, preferably between 1.0 and 7.0 MPa and even more preferably between 1.5 and 4.0 MPa. More preferably, a selective hydrogenation process is carried out in which the charge is a steam cracking essence comprising polyunsaturated compounds, the hydrogen / hydrogen molar ratio (polyunsaturated compounds to be hydrogenated) is between 0.7 and 5.0, the temperature is between 20 and 200 ° C, the hourly volume speed (VVH) is generally between 1 and 50 h ¹ and the pressure is between 1, 0 and 7.0 MPa.

Even more preferably, a selective hydrogenation process is carried out in which the filler is a steam cracking essence comprising polyunsaturated compounds, the hydrogen / hydrogen molar ratio (polyunsaturated compounds to be hydrogenated) is between 1.0 and 2.0, the temperature is between 30 and 180 ° C, the hourly volume speed (VVH) is generally between 1 and 50 h ¹ and the pressure is between 1, 5 and 4.0 MPa.

The hydrogen flow rate is adjusted in order to have enough of it to theoretically hydrogenate all of the polyunsaturated compounds and to maintain an excess of hydrogen at the outlet of the reactor.

In another embodiment according to the invention, when a selective hydrogenation process is carried out in which the filler is a C2 steam cracking cut and / or a C2-C3 steam cracking cut comprising polyunsaturated compounds, the molar ratio ( hydrogen) / (polyunsaturated compounds to be hydrogenated) is generally between 0.5 and 1000, preferably between 0.7 and 800, the temperature is between 0 and 300 ° C, preferably between 15 and 280 ° C, the speed hourly volume (VVH) is generally between 100 and 40,000 h ¹ , preferably between 500 and 30,000 h ¹ and the pressure is generally between 0.1 and 6.0 MPa, preferably between 0.2 and 5.0 MPa .

Description of aromatics

The present invention also relates to a process for the hydrogenation of at least one aromatic or polyaromatic compound contained in a hydrocarbon feed having a final boiling point less than or equal to 650 ° C, generally between 20 and 650 ° C , and preferably between 20 and 450 ° C. Said hydrocarbon feed containing at least one aromatic or polyaromatic compound can be chosen from the following petroleum or petrochemical cuts: the catalytic reforming reformate, kerosene, light diesel, heavy diesel, cracking distillates, such as FCC recycling oil, coking unit diesel, hydrocracking distillates. The content of aromatic or polyaromatic compounds contained in the hydrocarbon feedstock treated in the hydrogenation process according to the invention is generally between 0.1 and 80% by weight, preferably between 1 and 50% by weight, and particularly preferably between 2 and 35% by weight, the percentage being based on the total weight of the hydrocarbon charge. The aromatic compounds present in said hydrocarbon charge are, for example, benzene or alkylaromatics such as toluene, ethylbenzene, Go-xylene, m-xylene, or p-xylene, or alternatively aromatics having several aromatic rings (polyaromatics) such as naphthalene.

The sulfur or chlorine content of the feed is generally less than 5000 ppm by weight of sulfur or chlorine, preferably less than 100 ppm by weight, and particularly preferably less than 10 ppm by weight.

The technological implementation of the process for the hydrogenation of aromatic or polyaromatic compounds is for example carried out by injection, in upward or downward flow, of the hydrocarbon charge and of hydrogen in at least one fixed bed reactor. Said reactor can be of the isothermal type or of the adiabatic type. An adiabatic reactor is preferred. The hydrocarbon charge can advantageously be diluted by one or more re-injection (s) of the effluent, coming from said reactor where the hydrogenation reaction of aromatics takes place, at various points of the reactor, located between the inlet and the outlet of the reactor in order to limit the temperature gradient in the reactor. The technological implementation of the process for the hydrogenation of aromatics according to the invention can also be advantageously carried out by the implantation of at least said supported catalyst in a reactive distillation column or in reactors - exchangers or in a type reactor. slurry. The hydrogen flow can be introduced at the same time as the feed to be hydrogenated and / or at one or more different points of the reactor.

The hydrogenation of aromatic or polyaromatic compounds can be carried out in the gas phase or in the liquid phase, preferably in the liquid phase. In general, the hydrogenation of aromatic or polyaromatic compounds is carried out at a temperature between 30 and 350 ° C, preferably between 50 and 325 ° C, at a pressure between 0.1 and 20 MPa, from preferably between 0.5 and 10 MPa, at a hydrogen / (aromatic compounds to be hydrogenated) molar ratio between 0.1 and 10 and at an hourly volume velocity VVH of between 0.05 and 50 h ¹ , preferably between 0.1 and 10 h ¹ of a hydrocarbon charge containing aromatic or polyaromatic compounds and having a point final boiling point less than or equal to 650 ° C, generally between 20 and 650 ° C, and preferably between 20 and 450 ° C.

The hydrogen flow rate is adjusted in order to have enough of it to theoretically hydrogenate all of the aromatic compounds and to maintain an excess of hydrogen at the outlet of the reactor.

The conversion of the aromatic or polyaromatic compounds is generally greater than 20 mol%, preferably greater than 40 mol%, more preferably greater than 80 mol%, and particularly preferably greater than 90 mol% of the aromatic compounds or polyaromatics contained in the hydrocarbon feed. The conversion is calculated by dividing the difference between the total moles of aromatic or polyaromatic compounds in the hydrocarbon feedstock and in the product by the total moles of aromatic or polyaromatic compounds in the hydrocarbon feedstock.

According to a particular variant of the process according to the invention, a process for the hydrogenation of benzene of a hydrocarbon feedstock, such as the reformate from a catalytic reforming unit, is carried out. The benzene content in said hydrocarbon charge is generally between 0.1 and 40% by weight, preferably between 0.5 and 35% by weight, and particularly preferably between 2 and 30% by weight, the percentage by weight being based on the total weight of the hydrocarbon charge.

The sulfur or chlorine content of the feed is generally less than 10 ppm by weight of sulfur or chlorine respectively, and preferably less than 2 ppm by weight.

The hydrogenation of benzene contained in the hydrocarbon feed can be carried out in the gas phase or in the liquid phase, preferably in the liquid phase. When it is carried out in the liquid phase, a solvent may be present, such as cyclohexane, heptane, octane. In general, the hydrogenation of benzene takes place at a temperature between 30 and 250 ° C, preferably between 50 and 200 ° C, and more preferably between 80 and 180 ° C, at a pressure between between 0.1 and 10 MPa, preferably between 0.5 and 4 MPa, at a hydrogen / (benzene) molar ratio between 0.1 and 10 and at an hourly volume velocity VVH of between 0.05 and 50 h ¹ , preferably between 0.5 and 10 h ¹ .

The conversion of benzene is generally greater than 50% by mole, preferably greater than 80% by mole, more preferably greater than 90% by mole and particularly preferably greater than 98% by mole. Examples

The examples which follow specify the interest of the invention without however limiting its scope.

All the catalysts prepared in Examples 1 to 5 are prepared with an isotomer of nickel element. The support used for the preparation of each of these catalysts is a delta alumina having a pore volume of 0.67 ml_ / g and a BET specific surface area equal to 140 m ² / g.

Example 1 Preparation of the aqueous solution of Ni precursors

An aqueous solution of Ni precursors (solution S1) used for the preparation of catalysts A, B, C and D is prepared at 25 ° C by dissolving 276 g of nickel nitrate Ni (N0 ₃ ) ₂ .6H ₂ 0 (supplier Strem Chemicals®) in a volume of 100mL of demineralized water. The solution S1 is obtained, the NiO concentration of which is 19.0% by weight (relative to the mass of the solution). Example 2 (comparative): Preparation of a catalyst A by impregnation of nickel nitrate without additive

The solution S1 prepared in Example 1 is impregnated (7.4 ml of solution) dry on 10 g of said alumina support. The solid thus obtained is then dried in an oven for 16 hours at 120 ° C, then calcined under an air flow of 1 L / h / g of catalyst at 450 ° C for 2 hours.

The calcined catalyst A thus prepared contains 13.8% by weight of the nickel element supported on alumina and it has nickel oxide crystallites whose average diameter (determined by X-ray diffraction from the width of the line of diffraction located at the angle 2theta = 43 °) is 15.2 nm.

Example 3 (comparative): Preparation of a catalyst B by successive impregnation of nickel nitrate then of 4-oxopentanoic acid (levulinic acid)

Catalyst B is prepared by impregnating Ni nitrate (7.4 ml of solution) on said alumina support and then by impregnating levulinic acid using a molar ratio {levulinic acid / nickel} equal to 0.4.

To do this, the solution S1 prepared in Example 1 is impregnated dry on said alumina support. The solid B1 thus obtained is then dried in an oven for 16 hours at 120 ° C. Then, an aqueous solution B 'is prepared by dissolving 3.26 g of levulinic acid (CAS 123-76-2, supplier Merck®) in 20 ml of demineralized water. This solution B 'is then impregnated to dryness on 10 g of the solid B1 previously prepared. The solid thus obtained is then dried in an oven for 16 hours at 120 ° C, then calcined under an air flow of 1 L / h / g of catalyst at 450 ° C for 2 hours.

The calcined catalyst B thus prepared contains 13.8% by weight of the nickel element supported on alumina and it has nickel oxide crystallites with an average diameter of 5.2 nm.

Example 4 (invention): Preparation of a catalyst C by successive impregnation of nickel nitrate then of levulinic acid (4-oxopentanoic acid), with an additive molar ratio of nickel of 0.4, in the qazous phase using a solid vector (according to variant 2)

Catalyst C is prepared by impregnating Ni nitrate on said alumina support and then by impregnating levulinic acid in the gas phase using a molar ratio {levulinic acid / nickel} equal to 0.4. This method of preparation uses a solid vector.

To do this, the solution S1 prepared in Example 1 is impregnated dry on said alumina support. The solid C1 thus obtained is then dried in an oven for 16 hours at 120 ° C. Then, an aqueous solution C ’is prepared by dissolving 3.26 g of levulinic acid (CAS 123-76-2, supplier Merck®) in 20 ml of demineralized water. Solid C2 is obtained by dry impregnation of 7.4 ml of this solution C ’on said alumina support.

The solid C2 is then placed in a tubular reactor, for example a quartz tube of DN 50 mm provided with a sinter, on a layer of thin thickness (approximately 1 cm). A low surface inert bed is then deposited (on a layer of a few cm, here SiC from AGP), then the second solid C1. A carrier gas circulation (dry air in this case) is then carried out from the bottom to the top of the reactor (passing through C2 and then through C1). A flow of 1 L / h / g is used, the temperature rose to 120 ° C on the zone containing the solid C2 and to 30 ° C on that containing the solid C1. The system is evacuated via a vane pump placed on the head of the quartz tube. The device is maintained for 8 hours with a vacuum of at least 50 mbar. The conditions are chosen to transfer levulinic acid from solid C2 to solid C1 in vapor form. At the end of the time necessary for the transfer, the solid C1 having captured the levulinic acid becomes solid C.

The solid C thus obtained is then calcined under an air flow of 1 L / h / g of catalyst at 450 ° C for 2 hours.

The calcined catalyst C thus prepared contains 13.8% by weight of the nickel element supported on alumina and it has nickel oxide crystallites with an average diameter of 4.9 nm. Example 5 (invention): Preparation of a catalyst D by successive impregnation of nickel nitrate then of levulinic acid (4-oxopentanoic acid), with an additive molar ratio of nickel of 0.4, in the azose phase (according to the variant 1)

Catalyst D is prepared by impregnation of Ni nitrate on said alumina support and then by impregnation of levulinic acid in the gas phase using a molar ratio {levulinic acid / nickel} equal to 0.4.

To do this, the solution S1 prepared in Example 1 is impregnated dry on said alumina support. The solid D1 thus obtained is then dried in an oven for 16 hours at 120 ° C.

Then, 3.26 g of pure and undiluted levulinic acid (CAS 123-76-2, supplier Merck®) is deposited at the bottom of a saturator. Said saturator is connected to a quartz reactor where the solid D1 is placed on a porous sinter in a monolayer of solid. The reactor is 5.5 cm in diameter for the 10 g of solid to be treated. The saturator / reactor assembly is brought into uniform temperature. Under a nitrogen flow (150 NL / h) which is injected at the base of the saturator, the temperature of the saturator / reactor assembly is adjusted to a temperature of 120 ° C. The temperature conditions are chosen so that the additive has a vapor pressure of at least 400 Pa. The whole is left under a flow of nitrogen at temperature for 8 hours. The system is then inerted, the saturator is bypassed, and air is then injected into the same assembly. The reactor temperature only is increased (1 ° C / minute) under a flow of a 50/50 air / nitrogen mixture at 450 ° C for 2 hours.

The calcined catalyst D thus prepared contains 13.8% by weight of the nickel element supported on alumina and it exhibits nickel oxide crystallites with an average diameter of 4.9 nm.

EXAMPLE 6 Evaluation of the Catalytic Properties of Catalysts A to D in the Hydrogenation of Toluene

The catalysts A to D described in the examples above are tested against the hydrogenation reaction of toluene.

The selective hydrogenation reaction is carried out in a 500 mL stainless steel autoclave, equipped with mechanical agitation with magnetic drive and capable of operating under a maximum pressure of 100 bar (10 MPa) and temperatures between 5 ° C and 200 ° C.

Prior to its introduction into the autoclave, a quantity of 2 ml of catalyst is reduced ex situ under a hydrogen flow of 1 L / h / g of catalyst, at 400 ° C. for 16 hours (temperature rise ramp of 1 ° C / min), then it is transferred to the autoclave, protected from air. After adding 216 ml of n-heptane (supplier VWR®, purity> 99% chromanorm HPLC), the autoclave is closed, purged, then pressurized under 35 bar (3.5 MPa) of hydrogen, and brought to temperature of the test equal to 80 ° C. At time t = 0, approximately 26 g of toluene (supplier SDS®, purity> 99.8%) are introduced into the autoclave (the initial composition of the reaction mixture is then toluene 6% w / n-heptane 94% w / w) and l agitation is started at 1600 rpm. The pressure is kept constant at 35 bar (3.5 MPa) in the autoclave using a reservoir bottle located upstream of the reactor. The progress of the reaction is monitored by taking samples of the reaction medium at regular time intervals: the toluene is completely hydrogenated to methylcyclohexane. The consumption of hydrogen is also followed over time by the reduction in pressure in a reservoir bottle located upstream of the reactor. The catalytic activity is expressed in moles of H ₂ consumed per minute and per gram of Ni.

The catalytic activities measured for catalysts A to D are reported in Table 1 below. They are related to the catalytic activity measured for catalyst A (A _HY DI) ·

Table 1

The results appearing in Table 1 demonstrate that catalysts B, C and D, prepared in the presence of an organic compound (having at least one carboxylic acid type function), are more active than catalyst A prepared in the absence of this kind of organic compound. This effect is linked to the decrease in the size of the Ni particles. The method of introducing the additive also has an effect, which is not related to the size of the Ni particles, on the activity of the catalyst. A reduction in the nickel aluminate content is observed following this mode of introduction of the additive in the gas phase.

EXAMPLE 7 Evaluation of the Catalytic Properties of Catalysts A to D in Selective Hydrogenation of a Mixture Containing Styrene and Isoprene

The catalysts A to D described in the above examples are tested against the selective hydrogenation reaction of a mixture containing styrene and isoprene.

The composition of the filler to be selectively hydrogenated is as follows: 8% by weight styrene (supplier Sigma Aldrich®, purity 99%), 8% by weight isoprene (supplier Sigma Aldrich®, purity 99%), 84% by weight n-heptane (solvent ) (supplier VWR®, purity> 99% chromanorm HPLC). This feed also contains sulfur compounds in very low content: 10 ppm by weight of sulfur introduced in the form of pentanethiol (supplier Fluka®, purity> 97%) and 100 ppm by weight of sulfur introduced in the form of thiophene (supplier Merck®, purity 99 %). This composition corresponds to the initial composition of the reaction mixture. This mixture of model molecules is representative of a pyrolysis essence.

Prior to its introduction into the autoclave, an amount of 3 ml of catalyst is reduced ex situ under a hydrogen flow of 1 L / h / g of catalyst, at 400 ° C. for 16 hours (temperature rise ramp of 1 ° C / min), then it is transferred to the autoclave, protected from air. After adding 214 mL of n-heptane (supplier VWR®, purity> 99% chromanorm HPLC), the autoclave is closed, purged, then pressurized under 35 bar (3.5 MPa) of hydrogen, and brought to temperature of the test equal to 30 ° C. At time t = 0, approximately 30 g of a mixture containing styrene, isoprene, n-heptane, pentanethiol and thiophene are introduced into the autoclave. The reaction mixture then has the composition described above and the stirring is started at 1600 rpm. The pressure is kept constant at 35 bar (3.5 MPa) in the autoclave using a reservoir bottle located upstream of the reactor. The progress of the reaction is monitored by taking samples of the reaction medium at regular time intervals: the styrene is hydrogenated to ethylbenzene, without hydrogenation of the aromatic cycle, and the isoprene is hydrogenated to methyl-butenes. If the reaction is continued longer than necessary, the methyl butenes are in turn hydrogenated to isopentane. The consumption of hydrogen is also followed over time by the reduction in pressure in a reservoir bottle located upstream of the reactor. The catalytic activity is expressed in moles of H ₂ consumed per minute and per gram of Ni.

The catalytic activities measured for catalysts A to D are reported in Table 2 above. They are related to the catalytic activity measured for catalyst A (A _HYD2 ) ·

Table 2

The results appearing in Table 2 demonstrate that catalysts B, C and D, prepared in the presence of an organic compound (having at least one carboxylic acid type function), are more active than catalyst A prepared in the absence of this type of organic compound. This effect is linked to the decrease in the size of the Ni particles. The method of introducing the additive also has an effect, which is not related to the size of the Ni particles, on the activity of the catalyst. A reduction in the nickel aluminate content is observed following this mode of introduction of the additive in the gas phase.

Claims

1. Process for the hydrogenation of at least one polyunsaturated compound containing at least 2 carbon atoms per molecule, such as diolefins and / or acetylenics and / or aromatic or polyaromatic compounds, contained in a hydrocarbon charge having a final boiling point less than or equal to 650 ° C, which process being carried out at a temperature between 0 and 350 ° C, at a pressure between 0.1 and 20 MPa, at a hydrogen / hydrogen molar ratio (compound to be hydrogenated ) between 0.1 and 1000 and at an hourly volume velocity VVH of between 0.05 and 40,000 h ¹ in the presence of a catalyst comprising a porous support and an active phase comprising at least one metal from group VIII, said active phase does not comprising no group VIB metal, said catalyst being prepared according to at least the following steps:

a) adding to the porous support at least one organic compound containing oxygen and / or nitrogen but not comprising sulfur;

b) carrying out a step of bringing said porous support into contact with at least one solution containing at least one salt of a precursor of the phase comprising at least one group VIII metal;

c) the porous support obtained at the end of step b) is dried;

2. Method according to claim 1, in which step a) is carried out by placing said porous support and said organic compound in the liquid state and without physical contact simultaneously, at a temperature below the boiling point of said organic compound and under pressure and duration conditions such that a fraction of said organic compound is transferred in the gaseous state to the porous support.

3. The method of claim 2, wherein step a) is carried out by means of an addition unit of said organic compound comprising first and second compartments in communication so as to allow the passage of a gaseous fluid between the compartments, the first compartment containing the porous support and the second compartment containing the organic compound in the liquid state.

4. The method of claim 3, wherein the unit comprises an enclosure including the first and second compartments, the two compartments being in communication by gas.

5. Method according to claim 3, wherein the unit comprises two enclosures respectively forming the first and the second compartments, the two enclosures being in communication by gas.

6. Method according to any one of claims 3 to 5, in which step a) is carried out in the presence of a flow of a carrier gas flowing from the second compartment into the first compartment.

7. The method of claim 1, wherein step a) is carried out by bringing said porous support into contact with a porous solid comprising said organic compound under conditions of temperature, pressure and duration such that a fraction of said compound organic is transferred by gas from said porous solid to said porous support.

8. The method of claim 7, wherein step a) is carried out by placing in contact without physical contact of said porous support with said porous solid comprising said organic compound.

9. Method according to any one of claims 7 to 8, in which in step a) the porous support and the porous solid comprising said organic compound are of different porosity and / or chemical nature (s).

10. Method according to any one of claims 7 to 9, in which at the end of step a), the porous solid containing the organic compound is separated from said porous support and is returned to step a).

1 1. Process according to any one of claims 1 to 10, in which said organic compound is chosen from compounds comprising one or more chemical functions chosen from a carboxylic acid, alcohol, ester, aldehyde, ketone, ether, carbonate function, amine, azo, nitrile, imine, amide, carbamate, carbamide, amino acid, ether, dilactone, carboxyanhydride.

12. The method of claim 1 1, wherein said organic compound comprises at least one carboxylic function chosen from formic acid, ethanedioic acid (oxalic acid), propanedioic acid (malonic acid), pentanedioic acid ( glutaric acid), hydroxyacetic acid (glycolic acid), 2- hydroxypropanoic acid (lactic acid), 2-hydroxypropanedioic acid (tartronic acid), 2-hydroxybutanedioic acid (malic acid), acid 2 -hydroxypropane- 1,2,3-tricarboxylic acid (citric acid), 2,3-dihydroxybutanedioic acid (tartaric acid), 2,2'-oxidiacetic acid (diglycolic acid), 2-oxopropanoic acid (acid pyruvic), 4-oxopentanoic acid (levulinic acid).

13. The method of claim 1 1, wherein said organic compound comprises at least one alcohol function selected from methanol, ethanol, phenol, ethylene glycol, propane-1, 3-diol, butane-1 , 4-diol, pentane-1, 5-diol, hexane-1, 6-diol, glycerol, xylitol, mannitol, sorbitol, pyrocatechol, resorcinol, hydroquinol, diethylene glycol, triethylene glycol, polyethylene glycol having an average molar mass of less than 600 g / mol, glucose, mannose, fructose, sucrose, maltose, lactose, in any of their isomeric forms.

14. The method of claim 1 1, wherein said organic compound comprises at least one ester function chosen from a g-lactone or a d-lactone containing between 4 and 8 carbon atoms, g-butyrolactone, g-valerolactone, d-valerolactone, g- caprolactone, d-caprolactone, g-heptalactone, d-heptalactone, g-octalactone, d-octalactone, methyl methanoate, methyl acetate, methyl propanoate , methyl butanoate, methyl pentanoate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl laurate, methyl dodecanoate, ethyl acetate, ethyl propanoate , ethyl butanoate, ethyl pentanoate, ethyl hexanoate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, oxalate diethyl, diethyl malonate, diethyl succinate, diethyl glutarate, ad diethyl ipate, dimethyl methyl succinate, dimethyl 3-methylglutarate, methyl glycolate, ethyl glycolate, butyl glycolate, benzyl glycolate, methyl lactate, ethyl lactate, lactate butyl, tert-butyl lactate, ethyl 3-hydroxybutyrate, ethyl mandelate, dimethyl malate, diethyl malate, diisopropyl malate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, trimethyl citrate, triethyl citrate, ethylene carbonate, propylene carbonate, carbonate of trimethylene, diethyl carbonate, diphenyl carbonate, dimethyl dicarbonate, diethyl dicarbonate, di-tert-butyl dicarbonate, in any of their isomeric forms.

15. The method of claim 1 1, wherein said organic compound comprises at least one amine function chosen from ethylenediamine, diaminohexane, tetramethylenediamine, hexamethylenediamine, tetramethylethylenediamine, tetraethylethylenediamine, diethylenetriamine, triethylenetetramine.

16. The method of claim 1 1, wherein said organic compound comprises at least one amide function chosen from formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, l acetamide, N-methylacetamide, N, N-dimethylmethanamide, N, N-diethylacetamide, N, N-dimethylpropionamide, propanamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, y-lactam , caprolactam, acetylleucine, N-acetylaspartic acid, aminohippuric acid, N-acetylglutamic acid, 4-acetamidobenzoic acid, lactamide and glycolamide, urea, N-methylurea, N, N'-dimethylurea, 1, 1 - dimethylurea, tetramethylurea according to any one of their isomeric forms.

17. The method of claim 1 1, wherein said organic compound comprises at least one carboxyanhydride function selected from the group of O-carboxyanhydrides consisting of 5-methyl-1, 3-dioxolane-2,4-dione and acid 2,5-dioxo-1, 3-dioxolane-4-propanoïque, or in the group of N-carboxyanhydrides constituted by 2,5-oxazolidinedione and 3,4-dimethyl-2,5-oxazolidinedione.

18. The method of claim 1 1, wherein said organic compound comprises at least one dilactone function selected from the group of 4-membered cyclic dilactones consisting of 1,2-dioxetanedione, or from the group of 5-membered cyclic dilactones consisting with 1,3-dioxolane-4,5-dione, 1,5-dioxolane-2,4-dione, and 2,2-dibutyl-1,5-dioxolane-2,4-dione, or in the group of 6-membered cyclic dilactones consisting of 1, 3-dioxane-4,6-dione, 2,2-dimethyl-1, 3-dioxane-4,6-dione, 2,2,5-trimethyl- 1,3-dioxane-4,6-dione, 1,4-dioxane-2,5-dione, 3,6-dimethyl-1,4-dioxane-2,5-dione, 3,6-diisopropyl -1, 4-dioxane-2,5-dione, and 3,3-ditoluyl-6,6-diphenyl-1, 4-dioxane-2,5-dione, or in the group of 7-membered cyclic dilactones consisting with 1,2-dioxepane-3,7-dione, 1,4-dioxepane-5,7-dione, 1,3-dioxepane-4,7-dione, and 5-hydroxy-2,2- dimethyl-1, 3-dioxepane-4,7-dione.

19. The method of claim 1 1, wherein said organic compound comprises at least one ether function selected from the group of linear ethers consisting of diethyl ether, dipropyl ether, dibutyl ether, methyl tert-butyl ether, diisopropyl ether, di-tert-butyl ether, methoxybenzene, phenyl vinyl ether, isopropyl vinyl ether and isobutyl vinyl ether, or in the group of cyclic ethers consisting of tetrahydrofuran, 1,4-dioxane, and morpholine.

20. Process according to any one of claims 1 to 19, said process being a process for the hydrogenation of at least one aromatic or polyaromatic compound contained in a hydrocarbon charge having a final boiling point less than or equal to 650 ° C, said process being carried out in the gas phase or in the liquid phase, at a temperature between 30 and 350 ° C, at a pressure between 0.1 and 20 MPa, at a molar ratio of hydrogen / (aromatic compounds to be hydrogenated) between 0.1 and 10 and at an hourly volume speed VVH of between 0.05 and 50 h ¹ .

21. Process according to any one of Claims 1 to 19, in which the said process is a process for the selective hydrogenation of polyunsaturated compounds contained in a hydrocarbon feedstock having a final boiling point less than or equal to 300 ° C, which process being carried out at a temperature between 0 and 300 ° C, at a pressure between 0.1 and 10 MPa, at a hydrogen / hydrogen (polyunsaturated compounds to be hydrogenated) ratio between 0.1 and 10 and at a speed hourly volume between 0.1 and 200 h ¹ when the process is carried out in the liquid phase, or at a hydrogen / hydrogen (polyunsaturated compounds to be hydrogenated) ratio between 0.5 and 1000 and at an hourly volume speed between 100 and 40000 h ¹ when the process is carried out in the gas phase.