Method for decontaminating a spent catalyst by extracting metal contaminants

Abstract

The present invention relates to a method for decontaminating a spent catalyst comprising a group VIB metal and / or a group VIII metal, and a porous support based on oxide(s), and comprising coke and metal contaminants including at least nickel and vanadium, said method comprising: - a step of extracting at least one portion of metal contaminants from said spent catalyst by bringing said spent catalyst into contact with an extraction solution comprising sulfuric acid and at least one alcohol, in order to obtain a spent catalyst depleted in vanadium and nickel contaminants, which can be recycled in a method for hydroconversion or hydrotreatment of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel. The invention also relates to a method for hydroconversion of a hydrocarbon feedstock containing metals incorporating the recycling of a catalyst obtained by decontamination according to the decontamination method described.

Description

[0001] PROCESS FOR DECONTAMINATING A USED CATALYST BY EXTRACTION OF METAL CONTAMINANTS

[0002] Technical field

[0003] The present invention relates to the field of recycling catalysts originating in particular from hydrocarbon hydroconversion or hydrotreatment units. In particular, the present invention relates to a method for decontaminating a spent catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII and a porous support based on oxide(s), by extracting metallic contaminants including at least nickel and vanadium from the spent catalyst, with a view to reusing said catalyst in a hydroconversion or hydrotreatment unit.

[0004] Prior art

[0005] Most of the technological innovations needed for the energy transition (electric vehicles, wind turbines, fuel cells, batteries, etc.) require the massive use of metals. The rapidly growing demand for metals is causing tensions that are forcing manufacturers to seek solutions to minimize their metal consumption where possible, and in particular to explore ways to recycle metals and / or products incorporating these metals.

[0006] In the field of conversion and refining of hydrocarbon feedstocks, catalysts from hydroconversion or hydrotreatment units contain metals, and their recycling is a subject of growing interest within the framework of a circular economy becoming a model for many companies.

[0007] Hydroconversion and hydrotreating catalysts generally contain a metal-based active phase, namely at least one Group VIB metal and / or at least one Group VIII metal, and a porous support, and may also contain metal contaminants from the converted / treated hydrocarbon feedstock that have deposited on the catalysts during the hydroconversion or hydrotreating process.

[0008] When used in hydroconversion or hydrotreatment processes, the catalyst deactivates due to the accumulation of coke and / or sulfur compounds and / or other contaminants, particularly metallic ones, on the surface of the catalyst. After a certain period, its replacement is therefore necessary.

[0009] Contaminants originate from the hydrocarbon feedstock. The most common contaminants are metals such as nickel, vanadium, iron, and titanium, but also silicon, calcium, sodium, potassium, chlorine, and arsenic. The most common metals in crude oils and heavy feedstocks are vanadium and nickel. These metals are generally less present in lighter feedstocks. The most problematic contaminants in a hydroconversion and hydrotreatment catalyst, and more specifically in hydroconversion, are therefore vanadium and nickel. The reuse of spent catalysts in hydroconversion or hydrotreatment processes and / or the extraction of metals from spent catalysts, particularly metallic contaminants, for recycling in the field or for other applications using certain metals, are therefore particularly attractive today.

[0010] In hydrotreatment processes where the catalyst is generally used in the form of a fixed bed, catalyst replacement is typically carried out by shutting down the unit, unloading the spent catalyst and replacing it completely with so-called "fresh" catalyst that has never been used.

[0011] In ebullated bed hydroconversion processes, generally treating heavier and more contaminated feedstocks (by metals, sulfur, etc.) than fixed bed hydrotreatment processes, typically crude oils or heavy hydrocarbon fractions from the distillation of crude oil, also called petroleum residues, the supported catalyst is maintained in the ebullated bed reactor, which is a three-phase reactor (liquid, vapor and solid catalyst) operating in an ebullated bed, in the form of a fluidized bed thanks to internal liquid recirculation.An example of such an ebullated bed hydroconversion process is the H-OIL® process, licensed by Axens and described for example in patents US4521295, US4495060, US4457831, or US4354852, typically using one or more ebullated bed reactors in series and / or in parallel, under conditions of high pressure (for example 10-20 MPa) and high temperature (for example 410-440°C). This type of process mainly aims to convert the heavy feedstock into lighter fractions, which can be used as fuels, for example to produce gasolines or diesel fuels, or raw materials for petrochemicals, and is capable of severely converting the heavy feedstock containing high levels of contaminants, also called impurities, and over a long cycle time.This is accomplished by the regular, typically daily, replacement of a small portion of the catalyst inventory contained in the reactor with fresh catalyst: the supported catalyst, for example a NiMo catalyst on an alumina support which is a conventional hydroconversion catalyst, is partly renewed daily with fresh catalyst to compensate for the catalyst deactivation induced by carbon deposits (coke) and metal deposits contained in the feedstock, mainly vanadium and nickel, in the form of metal sulfides (vanadium sulfides and nickel sulfides). This addition of fresh catalyst is accompanied by the daily extraction of spent catalyst to maintain a constant catalyst volume in the reactor. The daily replacement rate can for example range from 0.01 to 8% by weight of the total mass of catalyst contained in the reactor (based on the mass of the fresh catalyst).

[0012] In general, the entire withdrawn spent hydroconversion catalyst is landfilled or sent to a metal recovery process aimed at recovering all the metals from the catalyst, without reuse of the catalyst, even if theoretically regeneration and / or rejuvenation are possible. In the catalyst metal recovery processes, these are mainly reused for the manufacture of special alloys, requiring complex purification operations, in particular to rid the recovered metals of compounds considered to be contaminants, such as arsenic, or problematic in view of the intended applications, such as phosphorus, the presence of which disrupts, for example, the properties of chrome steel alloys.

[0013] As mentioned in patent FR3033797 or patent EP3728518, it is possible to regenerate, or even rejuvenate by removing the deposited metals, the withdrawn spent catalyst, with a view to recycling it in the hydroconversion reactor. The regenerated and / or rejuvenated catalyst can then constitute all or part, with fresh catalyst, of the daily catalyst top-up carried out in the hydroconversion reactor. However, no details on the regeneration and / or rejuvenation of the catalyst are given in these patents.

[0014] The regeneration of spent hydroconversion / hydrotreatment catalysts (also sometimes called mild calcination) aims to remove the coke that has deposited on the surface of the catalyst. This is an economically and environmentally attractive process, as it allows these catalysts to be reused in industrial units rather than being landfilled or sent to metal recovery facilities. Regeneration generally consists of a heat treatment, generally between 350°C and 550°C, in the presence of pure or dilute oxygen, with the aim of removing at least some of the coke present on the spent catalyst by combustion. This regeneration allows the so-called "regenerated" catalyst to recover from the hydrotreatment / hydroconversion activity.Although regenerated catalysts are generally less active than fresh catalysts, which consequently implies a reduced cycle time in the hydroconversion / hydrotreatment unit compared to that of a fresh catalyst, their use nevertheless remains advantageous from a circular economy point of view. Patent US4621069 describes, for example, a regeneration of a hydroconversion catalyst of a hydroconversion process such as the H-OIL® process, in which the deactivated catalyst is continuously regenerated ex-situ by the combustion of coke. The simple regeneration step with reuse of the regenerated catalyst makes it possible to reduce the consumption of fresh catalyst. However, the gain is limited by the presence of catalyst fractions that are highly deactivated by metal deposits not removed during regeneration.

[0015] In order to compensate for the lack of hydrotreatment / hydroconversion activity of the regenerated catalyst, it is possible to apply an additional treatment called "rejuvenation". The rejuvenation process consists of re-impregnating the already regenerated catalyst with a solution containing organic or inorganic additives and / or metal precursors. These rejuvenation processes are well known, particularly in the field of middle distillates. Although more efficient than simple regeneration, catalyst rejuvenation leads in most cases to a catalyst with lower activity than the fresh catalyst, the use of which nevertheless remains interesting. Finally, some used catalysts cannot be reused via regeneration or rejuvenation, because they contain too large a quantity of contaminants making the performance of the regenerated and / or rejuvenated catalyst insufficient.

[0016] In this context, processes for extracting contaminants from used catalysts have been developed. These processes aim to extract contaminants, particularly vanadium and nickel, without extracting the active phase consisting of group VII and / or VIB metals, with the aim of restoring the original catalytic activity. The objective is therefore often to be able to recycle the catalyst freed from these contaminants. These processes generally involve extracting the contaminants using a solution containing an inorganic acid such as sulfuric acid. Such extraction of the metallic contaminants deposited on the catalyst is also sometimes referred to as a rejuvenation step, with rejuvenation then being understood more broadly as a step aimed at restoring the catalytic activity of the catalyst.

[0017] Thus, document US5906953 describes a process for removing the remains of the feedstock contained in the hydroconversion catalyst by deoiling using a solvent such as acetone, followed by washing with water, extraction of vanadium and nickel by a solution containing sulfuric acid, another washing with water and regeneration to remove the coke. Document US4595666 describes a similar process with deoiling, followed by washing with water, extraction of iron, titanium, calcium, sodium, vanadium and nickel by a solution containing sulfuric acid, optionally in the presence of an ammonium ion, another washing with water and regeneration to remove the coke.

[0018] The present invention provides an improved process for removing metal contaminants such as vanadium and nickel from a spent hydroconversion / hydrotreatment catalyst, using a specific sulfuric acid-based solution, with superior performance compared to using a sulfuric acid-based solution alone, while preferably preserving the metals of the active phase of the catalyst as much as possible.

[0019] Objectives and Summary of the Invention

[0020] The present invention aims to overcome at least in part the problems of the prior art described above, and aims in particular to provide a method for decontaminating a spent catalyst with a view to recycling it for the hydroconversion or hydrotreatment of hydrocarbon feedstocks, said spent catalyst comprising metallic contaminants, including at least nickel and vanadium, by extracting said contaminants from said spent catalyst using a solution comprising sulfuric acid and at least one alcohol. The catalyst obtained after decontamination, depleted in vanadium and nickel contaminants, and preferably regenerated, can thus be reused in a hydroconversion or hydrotreatment unit, in particular as a catalyst supplement, in whole or in part (alone or in combination with fresh catalyst), in an ebullated bed reactor during a hydroconversion step of a heavy hydrocarbon feedstock.

[0021] The present invention generally aims to reduce the overall consumption of fresh catalyst during a hydroconversion / hydrotreatment process, and thus to limit the consumption and waste of valuable resources such as metals involved in the hydroconversion / hydrotreatment processes.

[0022] Thus, to achieve at least one of the above-mentioned objectives, among others, the present invention proposes, according to a first aspect, a method for decontaminating a used catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII and a porous support based on oxide(s), and comprising coke and metallic contaminants including at least nickel and vanadium, said method comprising:

[0023] - a step of extracting at least a portion of the metallic contaminants from said spent catalyst by bringing said spent catalyst into contact with an extraction solution comprising sulfuric acid and at least one alcohol, to obtain a spent catalyst depleted in vanadium and nickel contaminants, recyclable in a process of hydroconversion or hydrotreatment of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel.

[0024] According to one or more implementations, the decontamination method comprises a step of regenerating said spent catalyst upstream of the extraction step, by removing at least part of the coke from said spent catalyst, preferably by combustion, to form a regenerated spent catalyst.

[0025] According to one or more implementations, the decontamination method comprises a step of regenerating said spent catalyst depleted in vanadium and nickel contaminants from the extraction step, by removing at least a portion of the coke from said spent catalyst depleted in vanadium and nickel contaminants, preferably by combustion, to form a regenerated spent catalyst depleted in vanadium and nickel contaminants.

[0026] According to one or more implementations, the regeneration step comprises combustion by contacting said spent catalyst or spent catalyst depleted in vanadium and nickel contaminants with a regeneration gas stream comprising oxygen, at a temperature between 250°C and 550°C, preferably between 300°C and 500°C.

[0027] According to one or more implementations, the used catalyst is first subjected to at least one pre-treatment step chosen from de-oiling, washing with water, and drying.

[0028] According to one or more implementations, the used catalyst is first subjected to:

[0029] - a deoiling step by bringing said used catalyst into contact with a stream of inert gas at a temperature between 300°C and 400°C, or by bringing it into contact with a hydrocarbon deoiling solvent, preferably chosen from the list consisting of a gasoline, a diesel, and an aromatic compound, preferably toluene, - a step of drying said deoiled used catalyst by bringing it into contact with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C,

[0030] - an optional step of washing said dried deoiled catalyst with water.

[0031] According to one or more implementations, the spent catalyst depleted in vanadium and nickel contaminants, optionally regenerated upstream or downstream of the extraction step, undergoes at least one post-treatment step chosen from de-oiling, washing with water, and drying, preferably washing with water followed by drying by contact with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C.

[0032] According to one or more implementations, said at least one alcohol of the extraction solution is chosen from the list consisting of methanol, ethanol, 1-propanol, 2-propanol (or isopropanol), 1-butanol, 2-butanol, 2-methyl-1-propanol, tert-butanol, 1,2-ethanediol (or ethylene glycol),

[0033] 1,2-propanediol (or propylene glycol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol,

[0034] 2,3-butanediol, 1,5-pentanediol and 1,6-hexanediol, preferably the alcohol is ethanol.

[0035] According to one or more implementations, the extraction solution comprising sulfuric acid and at least one alcohol is an aqueous solution.

[0036] According to one or more implementations, the sulfuric acid concentration of the extraction solution is between 1 g / L and 300 g / L, and the alcohol concentration of the extraction solution is between 100 g / L and 1000 g / L.

[0037] According to one or more implementations, the spent catalyst comprises coke in a content of between 2% and 90% by weight relative to the total weight of the fresh catalyst, vanadium contaminant in a content of between 0.1% by weight and 150% by weight relative to the total weight of the fresh catalyst, and nickel contaminant in a content of between 0.1% by weight and 150% by weight relative to the total weight of the fresh catalyst.

[0038] According to one or more implementations, the used catalyst comes from a fresh hydroconversion catalyst comprising:

[0039] - at least one metal from Group VIII, preferably chosen from nickel and cobalt, preferably nickel, in combination with at least one metal from Group VIB, preferably chosen from molybdenum and tungsten, preferably molybdenum;

[0040] - a porous support of oxide(s) comprising silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia or combinations thereof, and preferably alumina. According to a second aspect, the invention provides a hydroconversion process comprising: - a step of hydroconversion of a hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and at least one hydroconversion catalyst and;

[0041] - a step of withdrawing from said hydroconversion reactor a stream of said spent hydroconversion catalyst and introducing into said hydroconversion reactor a make-up comprising a stream of recycled hydroconversion catalyst, preferably in combination with a stream of fresh hydroconversion catalyst;

[0042] - a step of decontaminating said spent catalyst stream withdrawn by the decontamination process according to the invention, to produce said recycled hydroconversion catalyst stream.

[0043] According to one or more implementations, the make-up comprises between 5% and 100% by weight of said recycled hydroconversion catalyst stream, preferably between 10% and 95% by weight, relative to the total mass of the make-up.

[0044] According to one or more embodiments, the hydrocarbon feedstock contains a fraction of at least 50% by weight having a boiling point of at least 300°C, preferably said hydrocarbon feedstock comprises, and may consist of, one of the following feedstocks, alone or as a mixture: a crude oil, a synthetic crude oil, a coal tar, a bituminous sands bitumen, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion or hydrotreatment or hydrocracking or hydroconversion unit or from a direct coal liquefaction unit,a vacuum distillate obtained directly from a crude oil or from a cut from a fluidized bed catalytic cracking unit or from a hydrocracking unit or from a hydroconversion unit or from a coking unit or from a visbreaking unit, a vacuum distillate from the direct liquefaction of coal, aromatic cuts extracted from a lubricant production unit, a deasphalted oil or an asphalt from a deasphalting unit, and preferably a vacuum residue from the vacuum distillation of a crude oil.,

[0045] Other objects and advantages of the invention will appear on reading the following description of particular examples of embodiments of the invention, given as non-limiting examples.

[0046] Description of the embodiments

[0047] In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the methods. However, it will be apparent to those skilled in the art that the methods may be implemented without necessarily all of these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. In this description, the various embodiments presented may be implemented separately or in combination with each other, without limitation of combinations where technically feasible.

[0048] Terminology

[0049] It is specified that, throughout this description, the expression "between ... and ..." must be understood as including the limits cited, unless otherwise specified.

[0050] In this description, the term "comprise" is synonymous with "comprise", "include" and "contain", and is inclusive or open and does not exclude other elements not mentioned. It is understood that the term "comprise" includes the exclusive and closed term "consist".

[0051] Furthermore, when used in this description, and unless otherwise indicated, the terms "essentially" or "substantially" or "approximately" in relation to a reference value correspond to an approximation of ± 10%, preferably ± 5%, very preferably ± 2%, or even more preferably ± 1% of this reference value, which may be a temperature, a pressure, a distance, a speed, a flow rate, a content of compound(s), etc.

[0052] In the present description, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​may be combined with a more preferred range of temperature values.

[0053] According to the present invention, the pressures are absolute pressures, also noted abs., and are given in absolute MPa (or MPa abs.), unless otherwise indicated.

[0054] In the present description, the term "hydroconversion / hydrotreatment catalyst" means a porous supported catalyst used in an ebullated bed hydroconversion process or a hydrotreatment process, in particular in a fixed bed, of a hydrocarbon feedstock. In the remainder of the description, the term "catalyst" refers to such a hydroconversion / hydrotreatment catalyst, unless otherwise specified. Such catalysts typically comprise (i) a catalyst support having a large surface area and numerous interconnected channels or pores and (ii) an active phase in the form of fine particles of an active catalyst such as sulfides of cobalt, nickel, tungsten, molybdenum, or mixed sulfides of these elements (e.g. NiMo, CoMo, etc.), optionally phosphorus and / or sulfur, dispersed in the pores.Supported catalysts are commonly produced as cylindrical extrudates (pellets) or spherical solids, although other shapes are possible. Such a catalyst is detailed later in the description.

[0055] In this specification, the term "hydroconversion", also referred to by the acronyms "HDC" and "HCK" and by the term "hydrocracking" more commonly used when the feedstock concerned is a light feedstock, refers to a process whose primary purpose is to reduce the boiling point range of a hydrocarbon feedstock typically comprising at least 50% by weight of a heavy hydrocarbon fraction having a boiling point of at least 300°C, and in which a substantial portion of the feedstock is converted into products having lower boiling point ranges than those of the original feedstock. Hydroconversion generally involves the fragmentation of larger hydrocarbon molecules into smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen to carbon ratio.The reactions involved in hydroconversion reduce the size of hydrocarbon molecules, primarily by cleavage of carbon-carbon bonds, in the presence of hydrogen to saturate the cleaved bonds and aromatic rings. The mechanism by which hydroconversion occurs typically involves the formation of hydrocarbon free radicals during fragmentation, primarily by thermal cracking, followed by capping of the free radical ends or fragments with hydrogen in the presence of active catalyst sites. Of course, during a hydroconversion process, other reactions typically associated with hydrotreating may occur, such as, among others, the removal of sulfur or nitrogen from the feedstock, or the saturation of olefins, and as more broadly defined below.

[0056] The term "hydrotreating," commonly referred to as "HDT," refers to a milder operation than hydroconversion, whose primary purpose is to remove impurities such as sulfur, nitrogen, oxygen, halides, and trace metals from the feedstock, and to saturate olefins and / or stabilize hydrocarbon free radicals by reacting them with hydrogen rather than allowing them to react with themselves. The primary purpose is not to change the boiling point range of the feedstock. Thus, hydrotreatment includes in particular hydrodesulfurization reactions (commonly called "HDS"), hydrodenitrogenation reactions (commonly called "HDN") and hydrodemetalation reactions (commonly called "HDM"), accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydrodeasphalting and Conradson carbon reduction reactions.Hydrotreatment is most often carried out using a fixed-bed reactor, although other reactors can also be used for hydrotreatment, for example an ebullated bed hydrotreatment reactor. In the field of fuel production for other applications, hydrotreatment can thus make it possible to bring the hydrocarbon to the required specifications (sulfur content, aromatics, etc.) for a given application (car fuel, gasoline or diesel, domestic heating oil, etc.). Automotive standards, in particular, have imposed a very significant reduction in sulfur in diesel and gasoline fuels, hydrotreatment thus making it possible to bring these products to the required specifications.

[0057] Hydrotreatment thus improves the quality of hydrocarbons by reducing the content of certain compounds, elements considered as impurities, but it can also reduce the content of aromatic hydrocarbons, by hydrogenation, and thus improve the cetane index of fuels. During hydrotreatment processes, fuel gas and light cuts such as LPG (acronym for Liquefied Petroleum Gas) and naphtha can also be produced in small quantities.

[0058] Where standards are cited in this specification, they refer to the most recent published versions as of the date of filing of this application, unless otherwise specified.

[0059] In this description, the term "extraction" in reference to the metallic contaminants of the catalyst is synonymous with the term "leaching", unless otherwise indicated. The term "extraction" or "leaching" in this description is thus understood to mean the act of extracting one or more metals from a solid (spent catalyst) by dissolving them in a liquid (extraction or leaching solution).

[0060] In the present description, the expressions "metal contaminants" or "contaminating metals" refer indifferently to the metals considered as contaminants which have been deposited on the catalyst during its use, typically in a hydroconversion or hydrotreatment process, preferably hydroconversion, and which come from the hydrocarbon feedstock. The spent catalyst according to the present invention thus comprises metal contaminants including at least nickel and vanadium. Thus, in the present description, the expressions "vanadium contaminant" or "contaminating vanadium" will in particular designate the vanadium supplied by the feedstock and deposited on the catalyst during its use. Similarly, the expressions "nickel contaminant" or "contaminating nickel" designate the nickel supplied by the feedstock, which must be distinguished in the present invention from the nickel possibly contained in the active phase of the spent catalyst.Unlike nickel in the active phase, which is distributed homogeneously throughout the catalyst, contaminating nickel is generally only deposited on the surface of the catalyst.

[0061] Reference may also be made in this description to the "deposited metal content" to designate an average deposition rate of metals from the feedstock onto the catalyst during the hydroconversion or hydrotreatment step, and corresponds to the total mass of metals from the feedstock deposited in / on the catalyst during the hydroconversion / hydrotreatment divided by the total mass of fresh catalyst (the fresh catalyst comprising the support and the active phase). The deposited metal content is expressed as a mass percentage of metals relative to the total mass of fresh catalyst. When reference is made to the total mass of the fresh catalyst to express certain contents in mass % of catalyst compounds, this is the total mass of the fresh catalyst in its oxide (non-sulfurized) form.

[0062] The deposited metal content can be estimated mathematically from the metal content in the hydrocarbon feedstock, the total mass of hydrocarbon feedstock treated, the total demetallization performance of the feedstock (HDM reactions and / or deposits), the catalyst inventory (quantity) and the catalyst replacement rate in the case of hydroconversion. The metal content is preferably determined from analyses of the spent catalyst. According to this preferred approach, a sample of spent catalyst is taken, said sampled catalyst is washed in the laboratory using a Soxhlet extractor using a solvent such as toluene to extract the liquid products without extracting the metals, and then said washed catalyst sample is dried, typically in an atmospheric or vacuum oven, at a temperature sufficient to evaporate the solvent, for example at 120°C in the case of toluene.The washed and dried catalyst sample can then be analyzed to determine its elemental composition.

[0063] Preferably, the spent, washed and dried catalyst sample is regenerated, typically in an oven, for example at a temperature of about 500°C, to remove the coke. In the laboratory, regeneration is typically carried out in an air oven, preferably with a slow temperature increase (for example with one or more temperature steps) in order to avoid the formation of hot spots. The regenerated catalyst sample is then ground before being analyzed.

[0064] Elemental analyses, typically by inductively coupled plasma (ICP) spectrometry or X-ray fluorescence (XRF) spectrometry, are used to quantify the content of various catalyst elements, including aluminum and molybdenum for the most typical hydroconversion catalysts, as well as metals deposited during hydroconversion / hydrotreatment, such as vanadium and nickel for the most typical petroleum feedstocks treated in a hydroconversion process, and any other element. The deposited metal content (average deposition rate of metals from the feedstock onto the catalyst during the hydroconversion / hydrotreatment step) for the analyzed catalyst sample can be estimated by taking into account the known composition of the fresh catalyst.

[0065] It should be noted that in the sample of spent catalyst withdrawn from a hydroconversion reactor, there is an age distribution of the catalyst grains linked to a variable residence time in the reactor according to the grains typical of hydroconversion processes using an ebullated bed for example, and therefore also a distribution in deposits of deposited metals since the quantity of metals deposited during the hydroconversion depends on the residence time of the catalyst grain in the hydroconversion reactor (the longer the residence time, the greater the metal deposits on the grain). For the purposes of the present invention, the rate of deposited metals of the spent catalyst withdrawn from a hydroconversion reactor refers to the average mass of deposited metals relative to the total mass of fresh catalyst estimated in the analyzed catalyst sample.

[0066] In this description, the groups of chemical elements may be given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief DR Lide, 81 ème edition, 2000-2001). For example, group VIII (or VII IB) according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification, and group VIB to the metals of column 6. Elemental analyses, typically by inductively coupled plasma spectrometry (ICP), or by X-ray fluorescence spectrometry, more commonly called X-ray fluorescence (FX), make it possible to quantify the content of the different elements in the extraction solution and the catalyst pretreated at 550 °C in air.

[0067] Surprisingly, the inventors demonstrated that the use of a specific sulfuric acid-based solution, which combines sulfuric acid with at least one alcohol, allowed for the efficient extraction of metallic contaminants such as vanadium and nickel from spent hydroconversion / hydrotreatment catalysts, thus allowing the recycling of the decontaminated catalyst in a hydroconversion or hydrotreatment process.

[0068] Process for decontaminating used catalyst

[0069] According to a first aspect, the present invention relates to a method for decontaminating a spent catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII, optionally phosphorus and / or sulfur, and a porous support based on oxide(s), and comprising coke and metallic contaminants including at least nickel and vanadium. The method comprises a step of extracting at least a portion of metallic contaminants from said spent catalyst by contacting said spent catalyst with an extraction solution comprising sulfuric acid and at least one alcohol, to obtain a spent catalyst depleted in vanadium and nickel contaminants, recyclable in a process for hydroconversion or hydrotreatment of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel. The spent catalyst depleted in vanadium and nickel contaminants is also referred to in the present description as a "decontaminated catalyst".

[0070] The worn catalyst

[0071] The spent catalyst used in the decontamination process according to the invention is a catalyst comprising at least one metal from group VIB, and / or at least one metal from group VIII, optionally phosphorus and / or sulfur, and a porous support based on oxide(s). It also comprises coke and metallic contaminants including at least nickel and vanadium.

[0072] The spent catalyst is decontaminated during the metal contaminant extraction step of the process according to the invention, and is optionally regenerated, to provide a catalyst that can be recycled in the process from which it originated.

[0073] The spent catalyst preferably comes in particular from an ebullated bed reactor of a hydroconversion section of a hydroconversion process, or from a reactor, preferably a fixed bed reactor, of a hydrotreatment section of a hydrotreatment process, said processes treating a hydrocarbon feedstock containing metals including vanadium and nickel.

[0074] Conventional hydroconversion / hydrotreatment catalysts generally comprise a porous support based on oxide(s) and an active phase based on metals from groups VIB and VIII in their oxide forms, as well as phosphorus for conventional hydrotreatment catalysts. The preparation of these catalysts generally comprises a step of impregnation of the metals (and phosphorus for conventional hydrotreatment catalysts) onto the support, followed by drying and calcination to obtain the active phase in an oxidized form. Before their use in a hydroconversion and / or hydrotreatment reaction, these catalysts are generally also subjected to sulfurization.

[0075] The addition of an organic additive, particularly to hydrotreatment catalysts, to improve their activity is also known, especially for catalysts that have been prepared by impregnation followed by drying without subsequent calcination. These catalysts are often referred to as "additive-dried catalysts".

[0076] The catalysts used for the hydroconversion of certain feedstocks (typically light), generally called "hydrocracking", are classically of the bifunctional type, i.e. combining an acid function with a hydrogenating function. The acid function is provided by supports with large surface areas (150 to 800 m 2 .g -1generally) with significant acidity, such as halogenated aluminas (chlorinated or fluorinated in particular), combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites. The hydrogenating function is provided either by one or more metals from group VIII, or by a combination of at least one metal from group VIB and at least one metal from group VIII, implemented in the presence of sulfur. The balance between the two acid and hydrogenating functions governs the activity and selectivity of the catalyst.

[0077] When operating in a hydrotreatment or hydroconversion process, the catalyst is deactivated by accumulation on the surface of the catalyst of coke and / or sulfur compounds and / or other contaminants such as metallic contaminants like nickel, vanadium, iron, titanium, but also silicon, calcium, sodium, potassium, chlorine and arsenic.

[0078] The deposited metals can interact with the active sites of the catalyst, blocking them, reducing the catalyst's ability to catalyze reactions, i.e. leading to progressive deactivation of the catalyst. The nature of the deposited metals depends on the nature of the metals present in the treated feedstock of the hydroconversion process.

[0079] Coke deposits can also deactivate the active sites of the catalyst, or clog the pores and thus make the active sites less accessible to the reactants.

[0080] Beyond a certain period, its replacement is therefore necessary.

[0081] The quantity of metals and coke deposited depends, as does the nature of the metals, on the nature of the hydrocarbon charge.

[0082] In the case of ebullated bed hydroconversion, the amount of metals and coke deposited during hydroconversion varies from one catalyst grain to another, and is a function of the residence time of the catalyst grain in the hydroconversion reactor. The rate of metals deposited from the spent catalyst, particularly from the spent hydroconversion catalyst, can be between 5% and 150% by weight relative to the weight of fresh catalyst.

[0083] Typically, the spent catalyst, and in particular the spent hydroconversion catalyst, contains nickel and vanadium initially contained in the hydrocarbon feedstock and deposited on / in the catalyst during its use (contaminating nickel and vanadium).

[0084] The source catalyst, i.e. the spent catalyst, is therefore typically a hydroconversion or hydrotreatment catalyst, preferably a hydroconversion catalyst, which is described in detail below, after the following description of the hydrocarbon feedstock used in such hydroconversion / hydrotreatment processes, and which is the source of the catalyst contamination.

[0085] The hydrocarbon charge

[0086] The hydrocarbon feedstock targeted by hydroconversion and / or hydrotreatment can be of different types. The feedstock may be of fossil origin or derived from the conversion of biomass or waste, taken alone or in a mixture. The feedstocks that are treated, and in particular those mentioned below, generally contain heteroatoms such as sulfur, oxygen and nitrogen and other contaminants such as nickel, vanadium, iron, titanium, silicon, calcium, sodium, potassium, chlorine, and arsenic, nickel and vanadium being the most common metals in heavy feedstocks.

[0087] The fossil feedstock may be a cut from coal or hydrocarbons produced from natural gas, possibly in a mixture. It may also be oil or heavy petroleum or synthetic cuts, for example kerosene, diesel or distillates from atmospheric and vacuum distillation to produce kerosene, diesel or vacuum distillate which can be recovered either in a storage unit receiving products of the same type ("pool" in English), or in a downstream unit such as a catalytic cracking unit where the cuts sent are "cracked" to produce shorter chain hydrocarbons.

[0088] The fossil feedstocks used in a hydrotreatment process, in more detail, are for example gasolines, diesels, vacuum diesels, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuels, oils, waxes and paraffins, used oils, residues or deasphalted crudes, feedstocks from thermal or catalytic conversion processes, taken alone or in a mixture.

[0089] The feedstocks of fossil origin used in a hydroconversion process are typically heavy feedstocks containing a fraction of at least 50% by weight having a boiling point of at least 300°C, preferably at least 350°C, preferably at least 375°C, at least 450°C, preferably at least 500°C, and even more preferably at least 540°C. In more detail, these feedstocks may comprise, or consist of, one of the following feedstocks, alone or in a mixture: a crude oil, a synthetic crude oil, a coal tar, a tar sands bitumen, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil,an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion or hydrotreatment or hydrocracking or hydroconversion unit or a direct coal liquefaction unit (for example operated according to the H-Coal® process), a vacuum distillate obtained directly from a crude oil or a cut from a fluidized bed catalytic cracking unit (also called FCC for Fluid Catalytic Cracking according to English terminology) or from a hydrocracking unit or a hydroconversion unit or a coking unit or a visbreaking unit, a vacuum distillate from the direct liquefaction of coal, aromatic cuts extracted from a lubricant production unit, a deasphalted oil (also called DAO for Deasphalted Oil according to English terminology) or a asphalt from a deasphalting unit.,

[0090] The charges cited such as vacuum distillates, aromatic cuts and deasphalted oils for a hydroconversion process may enter into the composition of the charge of said process, preferably in a minority manner with another type of charge cited above.

[0091] Preferably, the fossil feedstocks used in a hydroconversion process comprise, and may consist of, a vacuum residue from the vacuum distillation of a crude oil.

[0092] The feedstock resulting from the conversion of biomass may advantageously be chosen from vegetable oils, algae or algal oils, fish oils, used edible oils, and fats of vegetable or animal origin; or mixtures of such feedstocks, typically containing triglycerides and / or free fatty acids and / or esters. Said vegetable oils may advantageously be crude or refined, totally or in part, and derived from plants chosen from rapeseed, sunflower, soybean, palm, olive, coconut (coconut oil and copra oil), castor oil, cotton, peanut, flax, crambe, jatropha and all oils derived from plants obtained by genetic modification or hybridization as may be the case for sunflower or rapeseed, this list not being exhaustive.Said animal fats are advantageously chosen from lard and fats composed of residues from the food industry or from the catering industries. Frying oils, various animal oils such as fish oils, tallow, lard can also be used. The feedstock resulting from the conversion of biomass can also advantageously be chosen from methyl esters of fatty acids of vegetable and / or animal origin or methyl esters of fatty acids from used edible vegetable oils. In an ebullated bed hydroconversion process, vegetable and / or animal oils or fats are preferably used as a co-feedstock in combination with another heavy liquid hydrocarbon feedstock.The feedstock from biomass conversion may also be selected from feedstocks from thermal or catalytic biomass conversion processes, such as oils that are produced from biomass, particularly lignocellulosic biomass, with various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, which includes plants, animals, and their by-products. The term "lignocellulosic biomass" refers to biomass derived from plants or their by-products. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and an aromatic polymer (lignin).

[0093] The feedstock from biomass conversion can also advantageously be chosen from feedstocks from the paper industry.

[0094] The feedstock from waste conversion can be pyrolysis oil from plastics, tires, or solid recovered fuels (SRF). Plastics are typically production scrap and / or waste (e.g., household waste, construction waste, electrical and electronic equipment waste), and preferably include polymers of alkenes, dienes, vinyls, styrenics, polyesters, and / or polyamides, and more preferably polyolefins, such as polyethylene (PE), polypropylene (PP), or copolymers of ethylene and propylene. These oils are obtained by thermal or catalytic pyrolysis treatment or can be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).In an ebullated bed hydroconversion process, it may also be considered to use a feedstock formed by solid plastic waste in combination with a heavy liquid feedstock, after specific conditioning of the co-feedstocks.

[0095] Heavy feedstocks of fossil origin used in a hydroconversion process contain metals already mentioned above, and typically other impurities such as sulfur, nitrogen, Conradson carbon and asphaltenes, in particular C7 asphaltenes which are insoluble in heptane.

[0096] The metal contents may be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight. For example, the cumulative nickel and vanadium content is greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight, or even greater than or equal to 150 or 200 ppm by weight.

[0097] The sulfur content may be greater than or equal to 0.1% by weight, or even greater than or equal to 0.5% or 1%, and may be greater than or equal to 2% by weight.

[0098] The nitrogen content can be between 1 ppm and 8000 ppm by weight, more generally between 200 ppm and 8000 ppm by weight, for example between 2000 ppm and 8000 ppm by weight.

[0099] The level of C7 asphaltenes (heptane-insoluble compounds according to ASTM D 6560, also corresponding to NF T60-115) can be at least 1% by weight and is often greater than or equal to 3% by weight (with the exception of a feedstock comprising mainly a DAO). C7 asphaltenes are compounds known to inhibit the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly called coke, and by their tendency to produce sediments which can severely limit the operability of hydroconversion units.

[0100] The Conradson carbon content may be greater than or equal to 3% by weight, or even at least 5% by weight. The Conradson carbon content is defined by ASTM D482 and represents for those skilled in the art a well-known evaluation of the quantity of carbon residues produced after pyrolysis under standard conditions of temperature and pressure. These contents are expressed as a % by weight of the total weight of the hydrocarbon feedstock.

[0101] All charges cited are liquid at the operating conditions of hydroconversion / hydrotreatment.

[0102] Composition of the used catalyst

[0103] According to the present invention, the term "spent catalyst" or "source catalyst" means the catalyst from which the metallic contaminants are to be extracted, which is an at least partially spent catalyst, i.e. one which has already been used in production, in particular in hydroconversion or hydrotreatment installations. This term also includes an at least partially spent capture mass.

[0104] Although the present invention aims at the recycling of catalysts originating in particular from hydrocarbon hydroconversion or hydrotreatment units, it is understood that the process according to the invention applies to any catalyst comprising at least one metal from group VIII and / or at least one metal from group VIB, and a porous support based on oxide(s), such as for example selective hydrogenation catalysts, hydrotreatment catalysts for residues (for example carried out in an ebullated bed) or Fischer-Tropsch catalysts.

[0105] The spent catalyst is preferably derived from a fresh, i.e., new (never used) hydroconversion / hydrotreatment catalyst, described below.

[0106] The fresh catalyst, and the spent catalyst from the fresh catalyst, comprise at least one metal from group VIII and / or at least one metal from group VIB, a porous support based on oxide(s), and optionally phosphorus.

[0107] The spent catalyst also includes as contaminants at least coke, vanadium and nickel. It may also, without limitation, include sulfur as well as other contaminants as described below.

[0108] The porous support based on oxide(s) of the fresh catalyst, and of the spent catalyst from the fresh catalyst, is advantageously a support comprising, and which may be constituted by, silica, alumina, silica-alumina (amorphous), titanium dioxide, magnesium oxides, clay, boron oxide, zirconia, or combinations of these materials, preferably comprising, and which may be constituted by, silica, alumina, silica-alumina (amorphous), titanium dioxide or combinations thereof. According to one embodiment, the support of the catalyst is essentially constituted by alumina, or silica or silica-alumina. Very preferably, the porous support is essentially constituted by alumina. The alumina may advantageously be in all its forms, known to those skilled in the art.For example, the alumina is selected from the group consisting of alpha, rho, chi, kappa, eta, gamma, theta and delta aluminas, preferably selected from gamma, theta and delta aluminas, and even more preferably is gamma alumina. According to another embodiment, the porous support is essentially a silica-alumina containing at least 50% by weight of alumina relative to the total weight of the support. The silica content in the support is at most 50% by weight relative to the total weight of the support, most often less than or equal to 45% by weight, preferably less than or equal to 40% by weight.

[0109] These materials are porous refractory oxides within which the metals of the active phase are classically dispersed.

[0110] In some cases, it may be advantageous for the support to comprise, in addition to the refractory oxide material described above, for example in addition to alumina, at least one zeolitic material, which may in particular provide a cracking function in addition to the hydro-dehydrogenating function provided by the metals of the active phase, said zeolitic material forming, with the refractory oxide, the porous support within which the metals of the active phase are dispersed. The content of zeolitic material in the support is for example between 0.1 and 80% by weight, preferably between 0.1 and 50% by weight relative to the total weight of the support. In this case, all known sources of zeolite and all known associated preparation methods may be incorporated.Said zeolitic material may be a zeolite chosen from zeolites of structure MFI, FAU, BEA, ISV, IWR, IWW, MEI, UWY, preferably MFI, FAU and BEA, more preferably FAU and BEAU, and preferably chosen from zeolites ZSM-5, beta and / or Y, even more preferably zeolite USY and / or beta. With regard to the zeolites mentioned in the present description, a person skilled in the art may refer to the work "Atlas of zeolite framework types", 6th revised Edition, 2007, Ch. Baerlocher, WM Meier, DH Olson to obtain the characteristics thereof.

[0111] According to one or more embodiments, in particular for hydrotreatment catalysts, the porous support based on oxide(s) has a total pore volume of between 0.1 and 1.5 mL / g, preferably between 0.4 and 1.1 mL / g. The total pore volume is measured by mercury porosimetry according to the ASTM D4284-92 standard with a wetting angle of 140°, for example using an Autopore III™ model device from the Microméritics™ brand.

[0112] According to one or more embodiments, in particular for hydrotreatment catalysts, the specific surface area of ​​the oxide support is advantageously between 5 and 400 m 2 .g -1 , preferably between 10 and 350 m 2 .g -1 , more preferably between 40 and 350 m 2 .g -1. The specific surface area is determined in the present invention by the BET method according to ASTM D3663. The active phase of the fresh catalyst, and of the spent catalyst from the fresh catalyst, comprises at least one metal from group VIB and / or at least one metal from group VIII. The metal from group VIB present in the active phase is preferably chosen from molybdenum and tungsten, or the mixture of these two elements. The metal from group VIII present in the active phase is preferably chosen from cobalt, nickel and the mixture of these two elements. The active phase of the catalyst is preferably chosen from the group formed by the combination of the elements nickel-molybdenum, cobalt-molybdenum, nickel-cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten and nickel-cobalt-tungsten.

[0113] The content of group VIII metal, e.g. nickel, is advantageously between 0.5% and 50% expressed by weight of metal oxide (e.g. NiO), preferably between 0.5% and 10% expressed by weight of metal oxide and preferably between 1% and 6% by weight. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO respectively.

[0114] The content of group VIB metal, e.g. molybdenum, is advantageously between 0% and 30% expressed by weight of metal oxide (e.g. molybdenum trioxide IVloOa), preferably between 1% and 30%, and preferably between 4% and 20% by weight.

[0115] The metal contents are expressed as a percentage by weight of metal oxide relative to the weight of fresh catalyst.

[0116] The fresh catalyst, and the spent catalyst from the fresh catalyst, may also comprise at least one doping element chosen from phosphorus, boron, silicon, preferably phosphorus. The dopant is an element added during the manufacture of the fresh catalyst which, in itself, has no catalytic character but which increases the catalytic activity of the active phase. The content of phosphorus added as a dopant is then preferably between 0.1 and 20% by weight expressed as P2O5 relative to the total weight of the fresh catalyst, preferably between 0.2 and 15% by weight, more preferably between 0.3 and 8% by weight expressed as P2O5.

[0117] The molar ratio of phosphorus added as a dopant during the manufacture of the fresh catalyst to the group VIB element in the fresh catalyst is preferably greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.01 and 0.9 and very preferably between 0.15 and 0.6.

[0118] The fresh catalyst, and the spent catalyst from the fresh catalyst, may comprise sulfur. The sulfur content in said source catalyst is then preferably between 1 and 15% by weight expressed as an element relative to the total weight of the fresh catalyst, preferably between 2 and 12%, and very preferably between 4 and 10% by weight. The sulfur content is measured by elemental analysis according to ASTM D5373. The sulfur may come from the hydrocarbon feedstock and / or from a sulfurization step of the fresh catalyst and / or from a sulfur compound added to the feedstock with a view to carrying out in situ sulfurization of the fresh catalyst for its use in the hydroconversion / hydrotreatment process. The sulfurization step generally required for the use of the catalyst consists of activating the catalyst by transforming, at least in part, the oxide phase into a sulfide-reducing medium.This activation treatment by sulfurization is well known to those skilled in the art and can be carried out in situ or ex situ by any method already described in the literature.

[0119] According to a preferred embodiment, the spent catalyst is derived from a fresh hydroconversion catalyst comprising: at least one metal from Group VIII, preferably chosen from nickel and cobalt, preferably nickel, in combination with at least one metal from Group VIB, preferably chosen from molybdenum and tungsten, preferably molybdenum;

[0120] - a porous support of oxide(s), serving as a support for the said metal(s) forming the active phase, comprising, and preferably essentially consisting of, silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia or combinations thereof, and preferably alumina.

[0121] These hydroconversion catalysts are well known to those skilled in the art.

[0122] The fresh catalyst, and the spent catalyst from the fresh catalyst, are advantageously used in the form of irregular and non-spherical extrudates, beads, pellets or agglomerates whose specific shape may result from a crushing step. Preferably it is advantageously used in the form of extrudates or beads. The beads have, for example, a diameter between 0.4 mm and 4.0 mm. The extrudates have, for example, a cylindrical shape with a diameter between 0.5 mm and 4.0 mm and a length between 1 mm and 5 mm. The extrudates may also be objects of a different shape such as trilobes, regular or irregular tetralobes, or other multilobes. Supported catalysts of other shapes may also be used. The size of these different shapes of porous supported catalysts may be characterized by means of the equivalent diameter.The equivalent diameter is defined as six times the ratio of the particle volume to the external surface area of ​​the particle. The porous supported catalyst, used in the form of extrudates, beads or other forms, thus has an equivalent diameter between 0.4 mm and 4.4 mm.

[0123] The spent catalyst comprises coke. It will be noted that the term "coke" in the present application refers to a hydrocarbon-based substance deposited on the surface of the catalyst during its use, highly cyclized and condensed and having an appearance similar to graphite.

[0124] The coke content, expressed as % by weight of the carbon element, may be between 2% and 90% by weight relative to the total weight of the fresh catalyst, preferably between 5% and 70% by weight, and most preferably between 5% and 50% by weight. In the case of spent catalysts from hydrotreatment units, which generally process lighter feeds than feeds sent to an ebullated bed hydroconversion process and less likely to form coke, the coke content of the spent catalyst may be between 2 and 20% by weight, preferably between 3 and 16% by weight and in particular between 4 and 14% by weight relative to the total weight of the fresh catalyst. In the case of spent catalysts from ebullated bed hydroconversion units, the coke content can range from 5% to over 20% by weight, typically up to 50% by weight, or even up to 70% by weight or even up to 90% by weight, relative to the total weight of the fresh catalyst. The coke content is determined according to ASTM D5373.

[0125] The spent catalyst includes metallic contaminants including at least nickel and vanadium, and may include other contaminating metals, such as iron, titanium, arsenic, silicon, calcium, sodium, potassium, and chlorine, as detailed below.

[0126] The spent catalyst is contaminated with nickel from the hydrocarbon feedstock. The nickel contamination content of the spent catalyst (in addition to that possibly present as an active phase on the fresh catalyst) is between 0.1% by weight and 150% by weight, and preferably between 0.1% by weight and 80% by weight relative to the total weight of the fresh catalyst.

[0127] The spent catalyst is contaminated with vanadium from the hydrocarbon feedstock. The vanadium contamination content of the spent catalyst is preferably between 0.1% by weight and 150% by weight, and preferably between 0.1% by weight and 80% by weight relative to the total weight of the fresh catalyst.

[0128] The spent catalyst may be contaminated with arsenic. The arsenic content may then be between 0.15% by weight and 2.5% by weight and preferably between 0.25% by weight and 2% by weight relative to the total weight of the fresh catalyst.

[0129] Preferably, the iron content of the spent catalyst is between 0 and 150% by weight, preferably between 0.15% by weight and 80% by weight and very preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0130] Preferably, the titanium content of the used catalyst is between 0 and 0.5% by weight, preferably between 0.01% and 0.5% by weight and very preferably between 0.02% by weight and 0.2% by weight relative to the total weight of the fresh catalyst.

[0131] The spent catalyst may be contaminated with silicon from the hydrocarbon feedstock. The silicon content may then be (in addition to that possibly present on the fresh catalyst) between 0 and 10% by weight and very preferably between 0.2% and 50% by weight relative to the total weight of the fresh catalyst.

[0132] Preferably, the calcium content of the spent catalyst is between 0 and 150% by weight, preferably between 0.15% by weight and 80% by weight and very preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0133] Preferably, the sodium content of the spent catalyst (in addition to that possibly present on the fresh catalyst) is between 0 and 150% by weight, preferably between 0.15% by weight and 80% by weight and very preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst. Preferably, the potassium content of the spent catalyst is between 0 and 150% by weight, preferably between 0.15% by weight and 80% by weight and very preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0134] Preferably, the chlorine content of the spent catalyst is between 0 and 0.5% by weight, preferably between 0.01% by weight and 0.5% by weight and very preferably between 0.02% by weight and 0.2% by weight relative to the total weight of the fresh catalyst.

[0135] The spent catalyst from a hydrotreatment process of a middle distillate feedstock (diesel, kerosene) or a naphtha feedstock is distinguished by lower vanadium and nickel contents (in addition to that of the active phase) than that of a catalyst from a hydroconversion process of a heavier feedstock. The vanadium and nickel contamination contents of a spent catalyst from a hydrotreatment process of a middle distillate feedstock (diesel, kerosene) or a naphtha feedstock are generally less than 10,000 ppm by weight of nickel, and less than 20,000 ppm by weight of vanadium relative to the weight of the spent catalyst.

[0136] Pretreatments (optional)

[0137] The spent catalyst may be subjected to at least one pretreatment step prior to the metal contaminant extraction step. The optional pretreatment step consists of preparing the spent catalyst for better extraction of the metal contaminants, and aims in particular to remove all or part of the residues of the hydrocarbon feedstock or one or more of the impurities possibly contained in said spent catalyst before the metal contaminant extraction step, by any method known to those skilled in the art. The pretreatment step may be chosen from deoiling, water washing and drying. These preliminary treatments are intended to make the metal contaminant extraction step more efficient, by physical or chemical treatments. Deoiling or water washing go in the same direction, by improving / increasing the contact between the extraction solution and the contaminants contained in the source catalyst.

[0138] - Deoiling

[0139] The discharge of the spent catalyst from a reactor of a hydrotreatment and / or hydroconversion unit is preferably followed by a deoiling step. This step essentially aims to remove the residues of the hydrocarbon feedstock from the catalyst particles. The deoiling step generally comprises contacting the spent catalyst with a stream of inert gas (i.e. essentially free of oxygen), for example in a nitrogen atmosphere or the like, at a temperature between 300°C and 400°C, preferably between 300°C and 350°C. The flow rate of inert gas is preferably 5 to 150 NL.h 1(flow rate per unit volume of catalyst), for a period preferably of between 3 hours and 7 hours. Alternatively, the deoiling step may be carried out by contacting with a deoiling solvent, preferably light hydrocarbons, for example by steam treatment or any other similar process. The hydrocarbon deoiling solvent is preferably chosen from the list consisting of gasoline, diesel, and an aromatic compound, preferably toluene.

[0140] - Drying

[0141] The deoiling step is generally followed by a drying step: the deoiled catalyst can be dried by contact with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C.

[0142] The drying gas is preferably an inert gas such as nitrogen.

[0143] - Washing with water

[0144] The used catalyst, possibly deoiled, can undergo a water washing step.

[0145] The volume of water used in this washing step is advantageously greater than the total pore volume of the spent catalyst. This volume may in particular be in a range from 2 to 20 times the total pore volume of the spent catalyst, preferably between 5 and 10 times said pore volume.

[0146] The washing step may be carried out at any suitable temperature, for example between 5°C and 150°C, preferably between room temperature (about 20°C) and 70°C.

[0147] During the washing step, it is advantageous to mix the spent catalyst to ensure efficient washing. The washing step can be carried out in continuous or batch mode, with batch mode being preferred as it limits the amount of water used. The washing step can be carried out in any solid / liquid extractor type unit or industrial mixer.

[0148] Metal contaminant extraction step

[0149] According to an essential aspect of the process according to the invention, a step is carried out for extracting at least a portion of the metal contaminants including vanadium and nickel from said spent catalyst using an extraction solution comprising sulfuric acid and at least one alcohol, to obtain a spent catalyst depleted in vanadium and nickel contaminants, also called decontaminated catalyst, which is recyclable in a process for hydroconversion and / or hydrotreatment of hydrocarbon feedstocks. A liquid extract comprising at least vanadium and nickel is also obtained.

[0150] The main objective of this extraction step is to extract metal contaminants, including vanadium and nickel (contamination) but also possibly other metal contaminants from the spent catalyst, while preferably limiting the extraction of the active phase, i.e. the metals of group VIII and / or VIB forming the active phase of the catalyst. The limitation of the extraction of metals from the active phase, during this step, can be reinforced by the presence of coke on the spent catalyst. Thus, the spent catalyst sent to the metal contaminant extraction step has preferably not undergone prior regeneration aimed at removing the coke, in order to benefit from this aspect of protection of the active phase by the coke.Without being bound by any theory, it would appear that the coke present in the catalyst protects the extraction of the active phase, in particular the extraction of the group VIB metal while the metallic contaminants which are on the surface of the catalyst are extracted. Carrying out a regeneration step upstream of the step of extraction of the metallic contaminants does not, however, go beyond the scope of the invention, as detailed below in the description of the regeneration step. The extraction of the metallic contaminants is in fact possible without the presence of coke on the used catalyst.

[0151] Preferably, said at least one alcohol of the extraction solution is chosen from the list consisting of methanol, ethanol, 1-propanol, 2-propanol (or isopropanol), 1-butanol, 2-butanol, 2-methyl-1-propanol, tert-butanol, 1,2-ethanediol (or ethylene glycol), 1,2-propanediol (or propylene glycol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol and 1,6-hexanediol.

[0152] Preferably, the alcohol in the extraction solution is ethanol.

[0153] The extraction solution is preferably an aqueous solution comprising sulfuric acid and at least one alcohol, preferably chosen from the list mentioned above, and preferably ethanol.

[0154] The extraction solution has a pH generally between 0.1 and 8.5, preferably between 0.5 and 6, preferably between 1 and 4.

[0155] The sulfuric acid concentration of the extraction solution is preferably defined so that the sulfuric acid / metal contaminants molar ratio is between 0.2 and 25, preferably between 0.2 and 11, preferably between 0.2 and 5, preferably between 0.4 and 2, and preferably between 0.4 and 1.2.

[0156] The sulfuric acid concentration of the extraction solution is generally between 1 g / L and 300 g / L, preferably between 5 g / L and 300 g / L, and particularly preferably between 10 g / L and 300 g / L.

[0157] The alcohol concentration in the extraction solution is advantageously between 100 g / L and 1000 g / L, preferably between 250 g / L and 1000 g / L, and particularly preferably between 350 g / L and 1000 g / L.

[0158] The extraction solution is chosen to maximize the extraction rate of metal contaminants that include vanadium and nickel, while preferably limiting the extraction of the group VIII and / or VIB metal from the active phase. The selective extraction of metal contaminants relative to the group VIII and / or VIB metals can for example be expressed through the extraction rates of metal contaminants, e.g. nickel and vanadium, relative to those of the group VIII and / or VIB metals, or by the mass ratios of vanadium extracted / group VIII (or VIB respectively) metal extracted and nickel extracted / group VIII (or VIB respectively) metal extracted, also called V / VII, V / VIB, Ni / VIII or Ni / VIB ratios. A high ratio expresses high selectivity, which is desired (a high content of metal contaminants is thus extracted but little active phase).Unexpectedly, the combination of sulfuric acid and at least one alcohol in the extraction solution shows an increase in extraction selectivity, expressed by these selectivity ratios. The applicant has demonstrated that a combination of sulfuric acid and alcohol makes it possible to observe a synergistic effect for extraction selectivity, in particular the use of such a solution makes it possible to extract more vanadium and nickel contamination relative to the extracted group VIII and / or VIB metal than a solution comprising only sulfuric acid (without alcohol). According to one or more embodiments according to the invention, the extraction solution may also contain an oxidant to promote the extraction of the metals. Preferably, the oxidant contained in the extraction solution is hydrogen peroxide. When an oxidant is present, the concentration is generally between 0.1 and 5.0 mol / L.

[0159] Contacting the spent catalyst with the extraction solution is preferably carried out under the following conditions:

[0160] The temperature is generally between 0 and 300°C, preferably between 10°C and 100°C, and more preferably between 15°C and 40°C. Particularly preferably, the temperature is room temperature (about 20°C).

[0161] The pressure is generally between atmospheric pressure and 20 bars (2 MPa), particularly between atmospheric pressure and 10 bars (1 MPa).

[0162] The contact time per extraction step is generally between 1 minute and 20 hours, preferably between 5 minutes and 300 minutes, and most preferably between 5 minutes and 120 minutes.

[0163] Preferably, this extraction step is carried out by bringing the spent catalyst into contact with a volume of said solution of between 1.5 and 60 times the volume of the spent catalyst. Preferably, the volume of said solution is of between 2 and 30 times the volume of the source catalyst and more preferably of between 2 and 20 times the volume of the spent catalyst, and particularly preferably of between 3 and 10 times the volume of the spent catalyst.

[0164] According to the present invention, "extraction" is understood to mean that there is an extraction step, but the extraction may be carried out by one extraction operation or a plurality of successive extraction operations.

[0165] All contacting modes in a single step or in several steps following a co-current, counter-current or cross-current mode are possible for the implementation of the extraction step in continuous mode. The extraction step includes contacting the extraction solution with the spent catalyst, then a solid / liquid separation step making it possible to obtain, on the one hand, a leached catalyst depleted in contaminants but containing the majority of the active phase, and, on the other hand, the extraction solution enriched in contaminants and containing as little extracted active phase as possible.

[0166] The extraction solution may be brought into contact with the spent catalyst by any method known to those skilled in the art, for example by suspending the spent catalyst in the extraction solution using a rotary stirrer or by fluidization, or by percolation of the extraction solution through a fixed bed containing the spent catalyst.

[0167] The liquid / solid separation can be carried out by any method known to those skilled in the art, for example by sedimentation, by filtration, by draining, for example by gravity, and / or by centrifugation.

[0168] The extraction step thus allows the extraction of most of the most problematic metallic contaminants, vanadium and nickel contamination. This extraction step also allows the extraction of other contaminants, such as iron, titanium, silicon, calcium, sodium, potassium, and to a lesser extent arsenic.

[0169] The extraction rate of vanadium, nickel (contamination), iron, titanium, silicon, calcium, sodium and potassium is generally between 30% and 100%, preferably between 50% and 100%, more preferably between 70 and 100%.

[0170] The extraction rate of arsenic is generally less than 20%, preferably less than 10%, more preferably less than 5%.

[0171] Although not desired, this extraction step may also extract a minor portion of the active phase, as well as a minor portion of phosphorus (possibly present in the spent catalyst) and alumina (from the support) possibly present in the spent catalyst.

[0172] The extraction rate of the group VIII metal from the active phase is generally between 0% and 10%, preferably between 0% and 5%, more preferably between 0% and 3%.

[0173] The extraction rate of the group VIB metal from the active phase is generally between 0% and 10%, preferably between 0% and 5%, more preferably between 0% and 3%.

[0174] The extraction rate of phosphorus and aluminum is generally between 0% and 10%, preferably between 0% and 5%, more preferably between 0% and 3%.

[0175] The extraction rate corresponds to the mass of the metal(s) extracted in the extraction solution relative to the mass of metal(s) initially present on the spent catalyst.

[0176] At the end of the extraction stage, we obtain, on the one hand, a leached catalyst depleted of contaminants, in particular vanadium and nickel (contamination) but still containing a major part of the active phase.

[0177] The liquid extract produced in the extraction step, comprising at least vanadium and nickel, can be sent to a separation step to produce one or more metal streams that can be reused for other applications (metallurgy, catalyst preparation, etc.), and a solution comprising sulfuric acid and / or alcohol recyclable in the extraction step to form part of the extraction solution.

[0178] Regeneration step (optional)

[0179] Preferably, the method for decontaminating used catalyst according to the invention may comprise a regeneration step to remove all or part of the coke, sulfur and / or chlorine from the used catalyst, as detailed below.

[0180] The regeneration step may be carried out upstream of the step of extracting the metal contaminants, typically after one or more pre-treatment steps such as de-oiling followed by possible washing with water and drying of the spent catalyst. Such a step of regenerating the spent catalyst upstream of the extraction step proceeds by removing at least a portion of the coke from said spent catalyst, preferably by combustion, to form a regenerated spent catalyst. Such a regeneration step upstream of the extraction step may make it possible, by removing or reducing the quantity of coke and other contaminants such as sulfur compounds or chlorine, to improve / increase the contact between the extraction solution and the metals to be extracted contained in the spent catalyst.

[0181] Preferably, when a regeneration step is desired, this is carried out downstream of the step of extracting the metal contaminants, on the decontaminated catalyst. Such a step of regenerating the spent catalyst downstream of the extraction step proceeds by removing at least a portion of the coke from said catalyst depleted in vanadium and nickel contaminants (decontaminated catalyst), preferably by combustion, to form a regenerated decontaminate, which is therefore a regenerated spent catalyst depleted in vanadium and nickel contaminants. In this way, the coke present in the step of extracting the metal contaminants seems advantageously to protect the active phase of the catalyst during the step of extracting the metal contaminants, so as to limit the dissolution of the metals in the active phase of the catalyst and the loss of catalyst activity which would result therefrom, as already explained above.

[0182] According to one or more embodiments, the method may comprise a regeneration step upstream of the step of extracting the metal contaminants and a regeneration step downstream of the step of extracting the metal contaminants.

[0183] The step of regenerating the spent or decontaminated catalyst is a catalyst regeneration step aimed at removing at least part, preferably essentially all, of the coke from the spent catalyst. Sulfur and chlorinated compounds may also be removed at this step. This is advantageously a thermal regeneration comprising the combustion of the coke from the spent or decontaminated catalyst. A method other than combustion may be used to remove the coke from the spent catalyst, without departing from the scope of the present invention, provided that this other method does not alter the catalyst or degrade its integrity. Thermal regeneration of a catalyst by combustion is known to those skilled in the art. This step consists of carrying out controlled combustion of the coke deposits from the catalyst. It makes it possible to restore part of the active sites of the catalyst by removing the coke which deactivates the sites, or limits or blocks the access of the reactants by clogging the pores.

[0184] During the regeneration step, other compounds may undergo oxidation, with sulfur or nitrogen compounds possibly forming SOx and NOx.

[0185] According to one or more embodiments, the regeneration step comprises combustion by bringing said spent catalyst or the decontaminated catalyst into contact with a flow of regeneration gas comprising oxygen, at a temperature between 250°C and 550°C, preferably between 300°C and 500°C.

[0186] In particular, according to one or more embodiments, when the regeneration is carried out on the spent catalyst upstream of the extraction step, the temperature operated during the regeneration is between 250°C and 450°C, preferably between 300°C and 400°C, in particular in order to control the elimination of the coke and in particular to retain a portion thereof on the catalyst, which can thus improve the performance in the downstream extraction step by a protective effect of the active phase as already described above. According to one or more embodiments, when the regeneration is carried out on the spent catalyst upstream of the extraction step, the temperature operated during the regeneration is between 320°C and 550°C, preferably between 360°C and 500°C.When the regeneration is carried out downstream of the extraction step, on the decontaminated catalyst resulting from the extraction step, the temperature operated during the regeneration is preferably between 320°C and 550°C, preferably between 360°C and 500°C.

[0187] The regeneration gas stream preferably comprises air.

[0188] Combustion regeneration begins with the introduction of the regeneration gas stream, for example air, advantageously mixed with an inert gas such as nitrogen, into the combustion reactor of the regeneration unit. This stream is controlled to maintain optimal combustion conditions and minimize the risk of damage to the spent catalyst. The temperature, pressure and oxygen composition of the gas stream are adjusted according to the specific characteristics of the catalyst and the operating conditions of the combustion reactor of the combustion unit.

[0189] The water content in the regeneration gas can generally be between 0 and 50% by weight. The gas flow rate of the regeneration gas stream can be from 20 to 2000 NL.h 1 (flow rate per unit volume of source catalyst), more preferably 30 to 1000 NL.h 1 , and particularly preferably from 40 to 500 NL.h 1 .

[0190] The combustion regeneration step can be implemented by any type of equipment known to those skilled in the art, for example comprising one or more combustion reactors which can be furnaces, including rotary furnaces and furnaces equipped with moving belts, horizontal bed reactors equipped with a propeller for the advancement and homogenization of the catalyst, vibro-fluidization devices, fixed bed reactors, moving bed reactors, fluidized bed reactors, fluidized bed reactors having the advantage of better temperature distribution in order to avoid hot spots.

[0191] Typical residence times are 1 hour to 5 hours, preferably 2 hours to 5 hours, more preferably 2.5 hours to 5 hours, and most preferably 3 hours to 5 hours.

[0192] During combustion regeneration, the regeneration gas stream containing oxygen coming into contact with the spent catalyst causes oxidation of the coke deposits. The heat released during the oxidation reaction helps maintain the combustion reactor temperature within the desired range (typically 350-600°C, preferably 400-550°C, more preferably 450-550°C). The temperature and the entire regeneration procedure are controlled so as not to damage the hydroconversion catalyst.

[0193] Once regeneration is complete, the flow of regeneration gas is stopped.

[0194] The regeneration step can be carried out in a delocalized manner relative to the metal contaminant extraction unit, or even relative to the hydroconversion or hydrotreatment unit from which the spent catalyst is obtained, which in the latter case can be referred to as ex-situ regeneration. Alternatively, the regeneration step can be carried out in line with the metal contaminant extraction step, or even with the hydroconversion or hydrotreatment process, i.e. in a non-delocalized manner relative to the metal contaminant extraction unit, or even not delocalized relative to the hydroconversion or hydrotreatment unit, which in this case can also be referred to as in-situ regeneration.

[0195] Preferably, the regeneration step is carried out discontinuously (also called “batch”) and at a frequency defined according to the desired catalyst management.

[0196] A discontinuous (batch) implementation of the regeneration step, whether in-situ or ex-situ, may require the use of buffer tanks for the withdrawn spent catalyst and / or the regenerated catalyst which will be recycled to the hydroconversion / hydrotreatment step.

[0197] Advantageously, the regenerated catalyst resulting from the regeneration step comprises less than 5% by weight of coke, preferably less than 3% by weight of coke, preferably less than 2% by weight of coke, preferably a coke content of between 0% and 4.9% by weight, preferably between 0% and 2.9% by weight, preferably between 0% and 1.9%, and particularly preferably between 0% and 1.0% by weight, or even less than 1% by weight of coke relative to the total weight of the regenerated catalyst.

[0198] The regenerated spent catalyst or the regenerated decontaminated catalyst is composed of the porous support based on oxide(s) and the active phase formed of at least one metal from group VIB and / or at least one metal from group VIII and optionally the phosphorus of the spent catalyst. The regenerated spent catalyst or the regenerated decontaminated catalyst contains substantially the same content of metal from group VIB and / or VIII as the spent catalyst.

[0199] The regenerated spent catalyst or the regenerated decontaminated catalyst is characterized by a specific surface area of ​​between 20 and 600 m 2 / g, preferably between 30 and 400 m 2 / g, preferably between 40 and 360 m 2 / g.

[0200] The pore volume of the regenerated or decontaminated regenerated spent catalyst is generally between 0.1 cm 3 / g and 1.6 cm 3 / g, preferably between 0.2 cm 3 / g and 1.3 cm 3 / g.

[0201] The sulfur content after regeneration is preferably between 0 and 4% by weight expressed as an element relative to the weight of the catalyst, preferably between 0 and 2% by weight. The chlorine content after regeneration is preferably between 0 and 1% by weight expressed as an element relative to the weight of the catalyst, preferably between 0 and 0.5% by weight.

[0202] Very preferably, the regenerated decontaminated catalyst is not or only slightly contaminated, that is to say contains a content of less than 100 ppm by weight of arsenic, less than 3% by weight of coke, less than 2% by weight of sulfur, less than 500 ppm by weight of nickel (in addition to the active phase), less than 200 ppm by weight of vanadium, less than 2000 ppm by weight of iron, less than 100 ppm by weight of titanium, less than 4000 ppm by weight of silicon, less than 500 ppm by weight of calcium, less than 1000 ppm by weight of sodium, less than 500 ppm by weight of potassium and less than 100 ppm by weight of chlorine relative to the weight of the regenerated decontaminated catalyst.

[0203] Post-processing (optional)

[0204] The decontaminated catalyst from the extraction step, optionally regenerated upstream or downstream of the extraction step, may undergo at least one post-treatment step chosen from deoiling, washing with water, and drying, preferably washing with water followed by drying by contact with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C.

[0205] The water washing and drying steps are similar to those described in the optional pretreatments, and their description is not repeated here.

[0206] Hydroconversion process

[0207] Recycling of the decontaminated catalyst is provided by the present invention, for recycling to hydroconversion / hydrotreatment, and in particular to a hydroconversion step in an ebullated bed reactor as a daily hydroconversion catalyst make-up, optionally supplementing fresh (new) catalyst to complete the make-up.

[0208] According to one aspect, the present invention therefore relates to a hydroconversion process comprising: - a step of hydroconversion of a hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and at least one hydroconversion catalyst and;

[0209] - a step of withdrawing from said hydroconversion reactor a stream of said spent hydroconversion catalyst and introducing into said hydroconversion reactor a make-up comprising a stream of recycled hydroconversion catalyst, preferably in combination with a stream of fresh hydroconversion catalyst;

[0210] - a step of decontaminating said spent catalyst stream withdrawn by the decontamination process according to the invention based on the extraction of metallic contaminants by means of an extraction solution comprising sulfuric acid and at least one alcohol, to produce said recycled hydroconversion catalyst stream.

[0211] The catalyst decontamination process has been extensively described above and is not repeated here.

[0212] The principle of implementing a hydroconversion process according to the invention is described below:

[0213] A hydrocarbon feedstock containing metals is sent to a hydroconversion step in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and a porous supported hydroconversion catalyst. Into said hydroconversion reactor is introduced a make-up comprising a stream of recycled hydroconversion catalyst, in possible combination with fresh catalyst partially compensating for a stream of spent hydroconversion catalyst withdrawn from the reactor.

[0214] The spent catalyst stream, which contains coke deposits and metal deposits, is sent to the decontamination process according to the invention, aimed at decontaminating, or even regenerating by removing the coke, the spent catalyst with a view to recycling it as a make-up in the hydroconversion reactor.

[0215] This recycling thus makes it possible to reduce the supply of fresh catalyst compared to a conventional system without recycling part of the used catalyst withdrawn and regenerated.

[0216] Charge

[0217] The feedstock, particularly the feedstock used in a hydroconversion process, has been described above in connection with the spent catalyst decontamination process, and its description is not repeated here.

[0218] Hydroconversion stage

[0219] The hydrocarbon feedstock is introduced into a hydroconversion reactor of the hydroconversion section, together with hydrogen (stream not shown). Said reactor comprises the hydroconversion catalyst.

[0220] Such a reactor is a three-phase reactor containing hydrogen and a fluidized bed catalyst called an ebullated bed, and operating with an ascending flow of liquid and gas. The hydroconversion section comprises one or more reactors operating in an ebullated bed and containing a hydroconversion catalyst, the reactors being able to be arranged in series and / or in parallel. At this stage, the catalyst is therefore maintained in the ebullated bed reactor(s), as described for the H-Oil® process, for example, in patents US4521295 or US4495060 or US4457831 or US4354852, in the article Aiche, March 19-23, 1995, Houston, Texas, article number 46d, "Second generation ebullated bed technology", or in chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" of the book "Catalysis by Transition Metal Sulphides", Technip Editions, 2013.Each reactor advantageously comprises a recirculation pump which makes it possible to maintain the porous supported solid catalyst in a bubbling bed by continuous recycling of at least part of a liquid fraction withdrawn at the upper part of the reactor and reinjected at the lower part of the reactor.

[0221] The ebullated bed reactor preferably comprises at least one inlet located at or near the lower portion of the reactor through which the feedstock is introduced together with the hydrogen, and an outlet at or near the upper portion of the reactor through which the hydroconverted effluent is withdrawn from the reactor. The reactor further advantageously comprises at least one inlet and one outlet for injecting catalyst makeup and withdrawing spent catalyst, as described in more detail below in the catalyst withdrawal and makeup step. The ebullated bed reactor further comprises an expanded catalyst zone comprising the catalyst (the ebullated bed). The ebullated bed reactor also comprises a lower catalyst-free zone located below the expanded catalyst zone, and an upper supported catalyst-free zone located above the expanded catalyst zone.The feed in the ebullated bed reactor continuously recirculates from the upper supported catalyst-free zone to the lower supported catalyst-free zone by means of a recycle conduit in communication with a boiling pump. At the top of the recycle conduit there is preferably a funnel-shaped recycle cup through which the feed is drawn from the upper supported catalyst-free zone. The internal recycled feed is mixed with "fresh" feed and additional hydrogen gas.

[0222] Because the catalyst is kept stirring by significant liquid recycling, the pressure drop across the reactor remains low and constant, and the reaction exotherms are quickly averaged across the catalytic bed, which is therefore almost isothermal and does not require, for example, the injection of cooling flows ("quenches" in English).

[0223] The use of such ebullated bed reactors also makes it possible to operate under more severe conditions than, for example, those operated in a fixed catalyst bed reactor, allowing for better overall conversion of the feedstock. Another advantage linked to the use of ebullated bed reactors is the long cycle time of the hydroconversion unit (without stopping the unit to replace the catalyst(s)), in particular thanks to the catalyst withdrawal and injection system allowing the continuous replacement of used catalyst without stopping the hydroconversion unit made possible by the operation of such a type of reactor.

[0224] A key aspect of ebullated bed reactor operation is the continuous replacement of the hydroconversion catalyst. Catalyst replacement is required in all hydrocarbon feedstock conversion processes (regardless of the reactor technology used, e.g., fixed-bed, moving-bed, or bubbling-fluidized-bed reactors), because the catalyst is deactivated primarily by deposition of metals contained in the feedstock and by coke deposition under hydroconversion operating conditions.

[0225] Although the ebullated bed technology ultimately allows for an increase in the time between two hydroconversion process shutdowns thanks to the continuous aspect of catalyst renewal, compared to other technologies such as fixed bed technologies, it requires the implementation of a continuous catalyst renewal system, with catalyst withdrawal and top-up every day. As the catalyst is very strongly mixed in the ebullated bed, after an initial stabilization period, an equilibrium state is reached for the catalyst age distribution and activity, thus allowing operation at constant operating conditions with consistent performance over time.The CRR catalyst renewal rate, which is a daily replacement rate, can vary from 0.01 to 8% by weight of the total mass of catalyst contained in the reactor (mass of fresh catalyst), depending on the feedstock treated, and this rate can be different for each hydroconversion reactor if several reactors are used.

[0226] Catalyst renewal thus compensates for the loss of activity due mainly to metal and coke deposits on the catalyst. Due to the very good mixing of the catalyst in the ebullated bed hydroconversion reactor, a disadvantage encountered is that the withdrawn spent catalyst consists of a mixture of very highly deactivated catalyst, moderately deactivated catalyst and almost new catalyst, so that the use of the catalyst in ebullated bed hydrotreatment reactors is not optimized.

[0227] The hydroconversion step is carried out under conditions making it possible to obtain a hydroconverted effluent, which contains the conversion products. The hydroconverted effluent has in particular a reduced content (relative to the feedstock) of hydrocarbons having a boiling point of at least 300°C, or at least 350°C, 375°C, 450°C, 500°C, or even 540°C depending on the nature of the feedstock. Said hydroconverted effluent also has a reduced content, relative to the feedstock, of metals, and / or sulfur, and / or nitrogen, and / or Conradson carbon, and / or asphaltenes, and / or other impurities initially contained in the feedstock, depending on the reactions carried out in the hydroconversion reactor and the composition of the feedstock. In particular, said hydroconverted effluent may advantageously have a reduced content, relative to the feed, of metals, sulfur, nitrogen, Conradson carbon, and asphaltenes.The hydroconversion step is preferably carried out under an absolute pressure of between 2 MPa and 38 MPa, more preferably between 5 MPa and 25 MPa, and even more preferably between 6 MPa and 20 MPa, at a temperature of between 300°C and 550°C, more preferably between 350°C and 500°C, preferably between 370°C and 450°C, and even more preferably between 400°C and 450°C.

[0228] The hourly space velocity (WH) is preferably between 0.05 h 1 and 10 a.m. 1(WH relative to the volume of each reactor). The hourly space velocity (WH), also called liquid hourly space velocity (LHSV) or hourly space velocity (HSV) according to English terminology, is defined here as the ratio between the hourly volume flow rate of the liquid feedstock (sent to the hydroconversion stage) and the volume of each hydroconversion reactor. According to a preferred implementation, the WH is between 0.1 h 1 and 10 a.m. 1 , more preferably between 0.1 h 1 and 5 a.m. 1 , even more preferably between 0.15 h 1 and 2 hours 1 , and even more preferably between 0.15 h 1 and 1 hour 1 .

[0229] According to another implementation, the overall WH, i.e. the flow rate of liquid feed sent to step b) relative to the volume of all the reactors if several hydroconversion reactors are used in step b), is between 0.05 h 1 and 0.09 h 1

[0230] The amount of hydrogen mixed with the charge is preferably between 50 and 5000 normal cubic meters (Nm 3 ) per cubic meter (m 3 ) of liquid charge, preferably between 100 Nm 3 / m 3 and 2000 Nm 3 / m 3 and very preferably between 200 Nm 3 / m 3 and 1000 Nm 3 / m 3 .

[0231] The catalyst, in particular the hydroconversion catalyst, has been described above in connection with the process of decontamination of the spent catalyst, and its description is not repeated here.

[0232] According to one or more embodiments, the hydroconversion process comprises a second hydroconversion step in at least one second ebullated bed reactor, of part or all of the hydroconverted effluent obtained at the end of the hydroconversion step, or optionally of a heavy cut resulting from an intermediate separation step described below.

[0233] The second hydroconversion step is carried out so as to produce a second hydroconverted effluent. Said second hydroconverted effluent advantageously contains a greater quantity of conversion products than the hydroconverted effluent from hydroconversion step 1, and in particular an even lower content of hydrocarbons having a boiling point of at least 300°C, or at least 350°C, 375°C, 450°C, 500°C, or even 540°C depending on the nature of the feedstock. The second hydroconverted effluent may be provided with a reduced Conradson carbon residue, and optionally a reduced quantity of metals, and / or sulfur, and / or nitrogen, and / or asphaltenes.

[0234] The second hydroconversion stage is carried out in a similar manner to that described for the first hydroconversion stage. This applies in particular to the operating conditions, the equipment used, the hydroconversion catalyst(s) used, with the exception of the details mentioned below.

[0235] In the second hydroconversion stage, the operating conditions may be similar or different from those of the first hydroconversion stage, the temperature remaining in the range between 300°C and 550°C, more preferably between 350°C and 500°C, more preferably between 370°C and 450°C, even more preferably between 400°C and 450°C, even more preferably between 400°C and 440°C, and even more preferably between 410°C and 435°C, and the amount of hydrogen introduced into the reactor remaining in the range between 50 Nm 3 / m 3 and 5,000 Nm 3 / m 3liquid charge, preferably between 100 Nm 3 / m 3 and 3,000 Nm 3 / m 3 , and even more preferably between 200 Nm 3 / m 3 and 2,000 Nm 3 / m 3 . The other pressure and WH parameters are in the same ranges as those described for the first hydroconversion stage.

[0236] The operating temperature in the second hydroconversion stage may be higher than the operating temperature in the first hydroconversion stage. This may allow for more complete conversion of the unconverted feedstock. Hydroconversion of liquid products from the first hydroconversion stage and feedstock are enhanced, as are hydrotreating reactions such as hydrodesulfurization and hydrodenitrogenation, among others. Operating conditions are chosen to minimize the formation of solids (e.g., coke).

[0237] According to one or more embodiments, the hydroconversion process comprises an intermediate separation step, between the first hydroconversion step of the feedstock and the second hydroconversion step, which separates part, or all, of the hydroconverted effluent from the first hydroconversion step, to produce at least two cuts, including a heavy cut boiling mainly at a temperature greater than or equal to 350°C.

[0238] The other cut(s) are one or more light and intermediate cut(s). The light cut thus separated mainly contains gases (H2, H2S, NH3, and C1-C4), naphtha (or gasoline, cut which boils at a temperature below 150°C), kerosene (cut which boils between 150°C and 250°C), and at least part of the diesel (or gas oil, fraction which boils between 250°C and 350°C, or even 375°C). The light cut can be sent at least partially to a fractionation unit where the light gases are extracted from said light cut, for example by passing through an expansion drum. The gaseous hydrogen thus recovered, which may have been sent to a purification and compression installation, can advantageously be recycled to the first hydroconversion stage, and / or to the second hydroconversion stage if it is implemented. The recovered hydrogen gas can also be used in other refinery facilities.

[0239] The optional separation step is carried out in a separation section which comprises any separation means known to a person skilled in the art. Said separation section may comprise one or more flash drums arranged in series, and / or one or more steam and / or hydrogen stripping columns, and / or an atmospheric distillation column, and / or a vacuum distillation column, and preferably consists of a single flash drum, commonly referred to as a "hot separator".

[0240] Conventionally, the hydroconverted effluent from the first hydroconversion stage or the second hydroconversion stage then undergoes, at least in part, a fractionation stage, which separates part or all of said hydroconverted effluent into several fractions including at least one heavy liquid product boiling predominantly at a temperature above 350°C, preferably above 500°C, and more preferably above 540°C. The heavy liquid product contains a portion boiling at a temperature above 540°C, called the residual fraction (or vacuum residue), which is the unconverted portion. The heavy liquid product may contain a portion of the diesel fraction boiling between 250°C and 375°C and a portion boiling between 375°C and 540°C (also called the vacuum distillate). This fractionation stage therefore produces at least two products including the heavy liquid product, the other product(s) being light and intermediate cut(s).The fractionation step may comprise a gas / liquid separation producing at least one gas stream comprising hydrogen and H 2S which may be sent to a hydrogen treatment and recycling step. The fractionation section comprises any separation means known to those skilled in the art, such as one or more flash drums arranged in series, and preferably a chain of at least two successive flash drums, one or more steam and / or hydrogen stripping columns, an atmospheric distillation column, a vacuum distillation column, for example an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

[0241] It is possible to recycle in the first hydroconversion stage part of the heavy liquid product resulting from fractionation, and / or part or all of another effluent resulting from a subsequent treatment (e.g. deasphalting) of the heavy liquid product resulting from fractionation.

[0242] Hydroconversion catalyst withdrawal and addition stage

[0243] The hydroconversion process according to the invention comprises a step of withdrawing a spent catalyst stream from the hydroconversion reactor and introducing into the reactor a make-up comprising a recycled catalyst stream, optionally in combination with fresh catalyst.

[0244] The principle of withdrawing spent catalyst and injecting additional catalyst, particularly fresh, into the hydroconversion reactor is known, and for example described in patent FR3033797. Thus, it is known that the catalyst, when it is spent, can be partially withdrawn, preferably at the bottom of the reactor, and replaced by introducing additional catalyst, either at the top or at the bottom of the reactor.

[0245] According to an essential aspect of the hydroconversion process according to the invention, the make-up comprises a stream of recycled catalyst from the decontamination process according to the invention, possibly in combination with fresh catalyst. The replacement of used catalyst is preferably carried out at regular time intervals, and preferably in bursts or almost continuously.

[0246] The withdrawal and injection of the make-up are carried out using a withdrawal and injection device advantageously adapted to continuous operation of the hydroconversion stage.

[0247] With this catalyst withdrawal / injection operation, it is therefore not necessary to stop the unit to change the used catalyst, nor to increase the reaction temperatures along the cycle to compensate for deactivation. In addition, working under constant operating conditions makes it possible to obtain constant yields and product qualities throughout the cycle.

[0248] According to one or more embodiments, the injected catalyst stream (make-up) comprises between 5% and 100% by weight of recycled catalyst (recycled hydroconversion catalyst stream), preferably between 10% and 95% by weight, more preferably between 10% and 80%, relative to the total mass of the make-up.

[0249] Such recycling of spent catalyst obtained during the spent catalyst treatment step makes it possible to reduce the overall consumption of fresh catalyst during the hydroconversion process, compared to a catalyst supplement formed exclusively from fresh catalyst, which makes it possible to reduce the operating costs of the process.

[0250] Examples

[0251] The examples below aim to show certain performances of a decontamination process according to the invention of a used catalyst.

[0252] Example 1 (not in accordance with the invention)

[0253] We start with a used catalyst called NiMo, containing molybdenum, nickel and nickel and vanadium contaminants deposited on an alumina support used in a hydroconversion process.

[0254] The fresh starting catalyst has a nickel content, expressed as NiO weight, of 4% by weight and a molybdenum content, expressed as MoOa weight, of 10% by weight, the percentages being expressed relative to the total mass of the catalyst.

[0255] The unregenerated spent catalyst contains 4.9% by weight of deposited nickel (contamination nickel) and 25.3% by weight of deposited vanadium (contamination vanadium), expressed as elements (Ni and V respectively) relative to the weight of the fresh catalyst.

[0256] An extraction step of nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (called source catalyst) and 100 g of extraction solution are introduced into a flask. The extraction solution is an aqueous solution containing 150 g / L of sulfuric acid. The mixture is stirred at room temperature at 200 rpm via a magnetic bar for 6 hours. The mixture is then filtered through a porosity 5 sintered glass, in order to recover a polymetallic solution on the one hand and a solid residue on the other hand. Analysis of the solution shows that it contains 1.2 g / L of molybdenum, 15 g / L of nickel and 28.2 g / L of vanadium. The calculated extraction rates of Mo, Ni and V are therefore 7.3%, 68.6% and 44.6% respectively. The V / Mo mass ratio is 23 and the Ni / Mo mass ratio is 12.

[0257] Example 2 (not in accordance with the invention)

[0258] We start with the same spent catalyst as that used in example 1 containing 4.9% by weight of deposited nickel and 25.3% by weight of deposited vanadium, expressed relative to the weight of the fresh catalyst.

[0259] An extraction step of nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (called source catalyst) and 100 g of ethanol are introduced into a flask. The mixture is stirred at room temperature at 200 rpm via a magnetic bar for 6 hours. The mixture is then filtered through a sintered glass of porosity 5, in order to recover a polymetallic solution on the one hand and a solid residue on the other hand. Analysis of the solution shows that it contains 0.125 g / L of molybdenum and 0.21 g / L of nickel and 0.665 g / L of vanadium. The calculated extraction rates of Mo, Ni and V are therefore 0.8%, 0.7% and 1.1% respectively. The V / Mo mass ratio is 5 and the Ni / Mo mass ratio is 2.

[0260] Example 3 (in accordance with the invention)

[0261] We start with the same spent catalyst as that used in examples 1 and 2, containing 4.9% by weight of deposited nickel and 25.3% by weight of deposited vanadium, expressed relative to the weight of the fresh catalyst.

[0262] An extraction step of nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (called source catalyst) and 100 g of extraction solution are introduced into a flask. The extraction solution is an aqueous solution containing 150 g / L of sulfuric acid and 270 g / L of ethanol. The mixture is stirred at room temperature at 200 rpm via a magnetic bar for 6 hours. The mixture is then filtered through a porosity 5 sintered glass, in order to recover a polymetallic solution on the one hand and a solid residue on the other hand. Analysis of the solution shows that it contains 0.2 g / L of molybdenum and 13 g / L of nickel and 22.1 g / L of vanadium. The calculated extraction rates of Mo, Ni and V are therefore 1.4%, 59.5% and 34.9% respectively. The V / Mo mass ratio is 93 and the Ni / Mo mass ratio is 55.

[0263] The extraction of metallic contaminants according to this example 3 allows a significantly more selective extraction than that of examples 1 and 2.

[0264] The catalyst obtained after extraction of the metallic contaminants from the used catalyst according to this example 3 has a level of catalytic performance substantially equivalent to that of a fresh catalyst.

Claims

Claims 1. A method for decontaminating a spent catalyst comprising at least one metal from group VIB, and / or at least one metal from group VIII and a porous support based on oxide(s), and comprising coke and metallic contaminants including at least nickel and vanadium, said method comprising: a step of extracting at least a portion of the metallic contaminants from said spent catalyst by bringing said spent catalyst into contact with an extraction solution comprising sulfuric acid and at least one alcohol, to obtain a spent catalyst depleted in vanadium and nickel contaminants, recyclable in a process for hydroconversion or hydrotreatment of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel.

2. Method according to claim 1, comprising a step of regenerating said spent catalyst upstream of the extraction step, by removing at least part of the coke from said spent catalyst, preferably by combustion, to form a regenerated spent catalyst.

3. Method according to claim 1 or claim 2, comprising a step of regenerating said spent catalyst depleted in vanadium and nickel contaminants from the extraction step, by removing at least a portion of the coke from said spent catalyst depleted in vanadium and nickel contaminants, preferably by combustion, to form a regenerated spent catalyst depleted in vanadium and nickel contaminants.

4. Method according to any one of claims 2 and 3, in which the regeneration step comprises combustion by contacting said spent catalyst or spent catalyst depleted in vanadium and nickel contaminants with a regeneration gas stream comprising oxygen, at a temperature between 250°C and 550°C, preferably between 300°C and 500°C.

5. Method according to any one of the preceding claims, in which the used catalyst is previously subjected to at least one pre-treatment step chosen from de-oiling, washing with water, and drying.

6. Method according to claim 5, in which the used catalyst is previously subjected to: - a deoiling step by bringing said used catalyst into contact with a stream of inert gas at a temperature between 300°C and 400°C, or by bringing it into contact with a hydrocarbon deoiling solvent, preferably chosen from the list consisting of a gasoline, a diesel, and an aromatic compound, preferably toluene, - a step of drying said deoiled spent catalyst by contacting with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C, - an optional step of washing said dried deoiled catalyst with water.

7. Method according to any one of the preceding claims, in which the spent catalyst depleted in vanadium and nickel contaminants, optionally regenerated upstream or downstream of the extraction step, undergoes at least one post-treatment step chosen from deoiling, washing with water, and drying, preferably washing with water followed by drying by contact with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C, more preferably between 80°C and 150°C.

8. A method according to any one of the preceding claims, wherein said at least one alcohol of the extraction solution is selected from the list consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, tert-butanol, 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol and 1,6-hexanediol, preferably the alcohol is ethanol.

9. A method according to any one of the preceding claims, wherein the extraction solution comprising sulfuric acid and at least one alcohol is an aqueous solution.

10. The method of claim 9, wherein the sulfuric acid concentration of the extraction solution is between 1 g / L and 300 g / L, and the alcohol concentration of the extraction solution is between 100 g / L and 1000 g / L.

11. Method according to any one of the preceding claims, in which the spent catalyst comprises coke in a content of between 2% and 90% by weight relative to the total weight of the fresh catalyst, vanadium contaminant in a content of between 0.1% by weight and 150% by weight relative to the total weight of the fresh catalyst, and nickel contaminant in a content of between 0.1% by weight and 150% by weight relative to the total weight of the fresh catalyst.

12. Process according to any one of the preceding claims, in which the spent catalyst is derived from a fresh hydroconversion catalyst comprising: at least one metal from Group VIII, preferably chosen from nickel and cobalt, preferably nickel, in combination with at least one metal from Group VIB, preferably chosen from molybdenum and tungsten, preferably molybdenum; a porous support of oxide(s) comprising silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia or combinations thereof, and preferably alumina.

13. Hydroconversion process comprising: - a step of hydroconversion of a hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and at least one hydroconversion catalyst and; - a step of withdrawing from said hydroconversion reactor a stream of said spent hydroconversion catalyst and introducing into said hydroconversion reactor a make-up comprising a stream of recycled hydroconversion catalyst, preferably in combination with a stream of fresh hydroconversion catalyst; - a step of decontaminating said spent catalyst stream withdrawn by the decontamination process according to any one of claims 1 to 12 to produce said recycled hydroconversion catalyst stream.

14. Hydroconversion process according to claim 13, wherein the make-up comprises between 5% and 100% by weight of said recycled hydroconversion catalyst stream, preferably between 10% and 95% by weight relative to the total mass of the make-up.

15. A hydroconversion process according to claim 13 or 14, wherein said hydrocarbon feedstock contains a fraction of at least 50% by weight having a boiling point of at least 300°C, preferably said hydrocarbon feedstock comprises, and may consist of, one of the following feedstocks, alone or in a mixture: a crude oil, a synthetic crude oil, a coal tar, a tar sands bitumen, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion or hydrotreatment or hydrocracking or hydroconversion unit or from a direct coal liquefaction unit,a vacuum distillate obtained directly from a crude oil or from a cut from a fluidized bed catalytic cracking unit or from a hydrocracking unit or from a hydroconversion unit or from a coking unit or from a visbreaking unit, a vacuum distillate from the direct liquefaction of coal, aromatic cuts extracted from a lubricant production unit, a deasphalted oil or an asphalt from a deasphalting unit, and preferably a vacuum residue from the vacuum distillation of a crude oil.,