METHOD FOR DECONTAMINATING A USED CATALYST BY EXTRACTION OF METALLIC CONTAMINANTS

Abstract

The present invention relates to a process for decontaminating a spent catalyst comprising a metal from Group VIB and / or a metal from Group VIII, and a porous oxide-based support, and containing coke and metallic contaminants including at least nickel and vanadium. The process comprises: - a step for extracting at least a portion of the metallic contaminants from the spent catalyst by contacting the 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 hydroconversion or hydrotreating process for hydrocarbon feedstocks, and a liquid extract containing at least vanadium and nickel. The invention also relates to a process for hydroconverting a hydrocarbon feedstock containing metals, incorporating the recycling of a catalyst obtained by decontamination according to the described decontamination process.

Description

Title of the invention: METHOD FOR DECONTAMINATING A USED CATALYST BY EXTRACTION OF METALLIC CONTAMINANTS technical field

[0001] The present invention relates to the field of recycling catalysts, particularly those from hydroconversion or hydrotreating units of hydrocarbons. In particular, the present invention relates to a process 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 hydrotreating unit. Prior art

[0002] 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 creating tensions that are pushing manufacturers to seek solutions aimed at minimizing their metal consumption where possible, and in particular to explore ways of recycling metals and / or products incorporating these metals.

[0003] In the field of hydrocarbon feed conversion and refining, the catalysts of hydroconversion or hydrotreating 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.

[0004] Hydroconversion and hydrotreating catalysts generally contain a metal-based active phase, namely at least one metal from group VIB and / or at least one metal from group VIII, and a porous support, and may also contain metallic contaminants from the converted / treated hydrocarbon feedstock that have been deposited on the catalysts during the hydroconversion or hydrotreating process.

[0005] During its use in hydroconversion or hydrotreating processes, the catalyst becomes deactivated by 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.

[0006] The 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 metals Vanadium and nickel are more prevalent in crude oils and heavy feedstocks. These metals are generally less common in lighter feedstocks. Therefore, vanadium and nickel are the most problematic contaminants in hydroconversion and hydrotreating catalysts, and particularly in hydroconversion catalysts.

[0007] The reuse of spent catalysts in hydroconversion or hydrotreating processes and / or the extraction of metals from spent catalysts, in particular metallic contaminants, for recycling in the field or for other applications using certain metals, are therefore particularly attractive today.

[0008] In hydrotreating processes where the catalyst is generally used in the form of a fixed bed, the replacement of the catalyst is classically carried out by stopping the unit, discharging the used catalyst and replacing it entirely with so-called "fresh" catalyst that has never been used.

[0009] In bubbling bed hydroconversion processes, which generally deal with heavier and more contaminated loads (by metals, sulfur, etc.) than fixed bed hydrotreating 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 bubbling bed reactor, which is a three-phase reactor (liquid, steam and solid catalyst) operating in a bubbling bed, in the form of a fluidized bed through internal liquid recirculation.An example of such a bubbling bed hydroconversion process is the H-OIL® process, licensed by Axens and described, for example, in patents US4521295, US4495060, US4457831, and US4354852. This process typically employs one or more bubbling bed reactors in series and / or parallel, operating under high pressure (e.g., 10-20 MPa) and high temperature (e.g., 410-440°C) conditions. This type of process primarily aims to convert heavy feedstocks into lighter fractions that can be used as fuels, for example, to produce gasoline or diesel, or as raw materials for the petrochemical industry. It is capable of severely converting heavy feedstocks containing high levels of contaminants, also known as impurities, over a long cycle time.This is accomplished by the regular, typically daily, replacement of a small portion of the catalyst inventory 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 partially renewed daily with fresh catalyst to compensate for catalyst deactivation induced by carbon (coke) and metal deposits contained in the feedstock, primarily vanadium and nickel, in the form of metal sulfides (vanadium sulfides and nickel sulfides). This addition of fresh catalyst is accompanied by... The daily removal of spent catalyst is necessary to maintain a constant volume of catalyst 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 fresh catalyst).

[0010] Generally, all of the spent hydroconversion catalyst is disposed of in a landfill or sent to a metal recovery facility designed to recover all the metals from the catalyst, without reusing the catalyst itself, even though regeneration and / or rejuvenation are theoretically possible. In catalyst metal recovery facilities, these metals are primarily reused in the manufacture of special alloys, requiring complex purification processes, particularly to remove compounds considered contaminating, such as arsenic, or problematic for the intended applications, such as phosphorus, the presence of which, for example, disrupts the properties of chromium steel alloys.

[0011] As mentioned in patent FR3033797 or patent EP3728518, it is possible to regenerate, or even rejuvenate by removing deposited metals, the used catalyst that has been withdrawn, with a view to recycling it in the hydroconversion reactor. The regenerated and / or rejuvenated catalyst can then constitute all or part, along 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.

[0012] The regeneration of spent hydroconversion / hydrotreating catalysts (also sometimes called soft calcination) aims to remove the coke that has deposited on the surface of the catalyst. This is an economically and environmentally advantageous process, as it allows these catalysts to be reused in industrial units rather than being sent to landfills or metal recovery facilities. Regeneration generally consists of a heat treatment, usually between 350°C and 550°C, in the presence of pure or diluted 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 regain hydrotreating / hydroconversion activity.Although regenerated catalysts are generally less active than fresh catalysts, consequently resulting in a shorter cycle time in the hydroconversion / hydrotreating unit compared to that of a fresh catalyst, their use remains advantageous from a circular economy perspective. For example, US patent 4621069 describes the regeneration of a hydroconversion catalyst in a hydroconversion process such as the H-OIL® process, in which the deactivated catalyst is continuously regenerated ex-situ by coke combustion. This simple regeneration step with reuse of the regenerated catalyst reduces the consumption of fresh catalyst. However, the... The gain is limited by the presence of catalyst fractions that are strongly deactivated by metal deposits not removed during regeneration.

[0013] To compensate for the reduced hydrotreating / hydroconversion activity of the regenerated catalyst, an additional treatment known as "rejuvenation" can be applied. The rejuvenation process consists of re-impregnating the already regenerated catalyst with a solution containing organic or inorganic additives and / or metallic precursors. These rejuvenation processes are well known, particularly in the field of middle distillates. Although more efficient than simple regeneration, catalyst rejuvenation generally results in a catalyst with lower activity than the fresh catalyst, which nevertheless remains a valuable tool.

[0014] Finally, some spent catalysts cannot be reused via regeneration or rejuvenation because they contain too much contamination, making the performance of the regenerated and / or rejuvenated catalyst insufficient.

[0015] In this context, processes for extracting contaminants from spent catalysts have been developed. These processes aim to extract contaminants, particularly vanadium and nickel, without removing the active phase consisting of Group VII and / or VIB metals, with the objective of restoring the original catalytic activity. The goal is thus often to be able to recycle the catalyst free of these contaminants. These processes generally involve extracting the contaminants using a solution containing an inorganic acid such as sulfuric acid. Such extraction of metallic contaminants deposited on the catalyst is also sometimes referred to as a rejuvenation step, rejuvenation then being understood more broadly as a step aimed at restoring the catalytic activity of the catalyst. Thus, US patent 5906953 describes a process for removing residual feedstock from the hydroconversion catalyst by deoiling with a solvent such as acetone, followed by water washing, extraction of vanadium and nickel with a sulfuric acid solution, another water wash, and regeneration to remove coke. US patent 4595666 describes a similar process involving deoiling, followed by water washing, extraction of iron, titanium, calcium, sodium, vanadium, and nickel with a sulfuric acid solution, optionally in the presence of an ammonium ion, another water wash, and regeneration to remove coke.

[0016] The present invention proposes an improved method for extracting metallic contaminants such as vanadium and nickel from a spent hydroconversion / hydrotreating catalyst, using a specific sulfuric acid-based solution, with superior performance compared to the use of a solution based on sulfuric acid alone, while preferably preserving as much as possible the metals of the active phase of the catalyst. Objectives and Summary of the Invention

[0017] The present invention aims to overcome, at least in part, the prior art problems described above, and in particular to provide a method for decontaminating a spent catalyst for its recycling in the hydroconversion or hydrotreating of hydrocarbon feedstocks, said spent catalyst containing 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 hydrotreating unit, in particular as a catalyst supplement, in whole or in part (alone or in combination with fresh catalyst), in a bubbling bed reactor during a hydroconversion step of a heavy hydrocarbon feedstock.

[0018] The present invention generally aims to reduce the overall consumption of fresh catalyst during a hydroconversion / hydrotreating process, and thus to limit the consumption and waste of valuable resources such as metals involved in hydroconversion / hydrotreating processes.

[0019] Thus, to achieve at least one of the aforementioned objectives, among others, the present invention proposes, according to a first aspect, a decontamination process for a spent catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII and a porous oxide-based support, and comprising coke and metallic contaminants including at least nickel and vanadium, said process comprising: - an extraction step of at least part of the metallic contaminants of 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 hydroconversion or hydrotreating process of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel.

[0020] According to one or more implementations, the decontamination process includes a step of regenerating said spent catalyst upstream of the extraction step, by removing at least part of the coke of said spent catalyst, preferably by combustion, to form a regenerated spent catalyst.

[0021] According to one or more embodiments, the decontamination process includes 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 of vanadium and nickel contaminants, preferably by combustion, to form a regenerated spent catalyst depleted of vanadium and nickel contaminants.

[0022] According to one or more embodiments, the regeneration step includes combustion by contacting said spent catalyst or the spent catalyst depleted in vanadium and nickel contaminants with a regeneration gas stream containing oxygen, at a temperature between 250°C and 550°C, preferably between 300°C and 500°C.

[0023] According to one or more embodiments, the spent catalyst is previously subjected to at least one pre-treatment step chosen from oil removal, water washing, and drying.

[0024] According to one or more embodiments, the spent catalyst is previously subjected to: - a deoiling step by contacting said spent catalyst with a stream of inert gas at a temperature between 300°C and 400°C, or by contacting it with a hydrocarbon deoiling solvent, preferably chosen from the list consisting of gasoline, diesel, and an aromatic compound, preferably toluene, - a drying step of said deoiled spent catalyst by contacting it with a drying gas and / or by heating it, 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 de-oiled catalyst with water.

[0025] According to one or more embodiments, 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 oil removal, water washing, and drying, preferably water washing 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.

[0026] According to one or more embodiments, 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, preferably the alcohol is ethanol.

[0027] According to one or more embodiments, the extraction solution comprising sulfuric acid and at least one alcohol is an aqueous solution.

[0028] According to one or more implementations, the concentration of sulfuric acid in the 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.

[0029] 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.

[0030] According to one or more embodiments, 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 their combinations, and preferably alumina.

[0031] According to a second aspect, the invention proposes a hydroconversion process comprising: - a hydroconversion step of a hydrocarbon feed containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in a bubbling 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 of introducing into said hydroconversion reactor a top-up comprising a stream of recycled hydroconversion catalyst, preferably in combination with a stream of fresh hydroconversion catalyst; - a decontamination step of said spent catalyst stream withdrawn by the decontamination process according to the invention, to produce said recycled hydroconversion catalyst stream.

[0032] According to one or more implementations, the top-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 top-up.

[0033] 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 in mixture: crude oil, synthetic crude oil, coal tar, bitumen from oil sands, heavy oil from oil shale, atmospheric residue or vacuum residue from the atmospheric or vacuum distillation of crude oil, atmospheric residue spherical or vacuum residue from atmospheric or vacuum distillation of effluent from a thermal conversion unit or hydrotreating or hydrocracking or hydroconversion unit or a direct coal liquefaction unit, vacuum distillate obtained directly from crude oil or a cut from a fluidized bed catalytic cracking unit or a hydrocracking unit or a hydroconversion unit or a coking unit or a visbreaking unit, vacuum distillate from direct coal liquefaction, aromatic cuts extracted from a lubricant production unit, deasphalted oil or asphalt from a deasphalting unit, and preferably vacuum residue from vacuum distillation of crude oil.

[0034] Other objects and advantages of the invention will become apparent from the following description of particular embodiments of the invention, given by way of non-limiting examples. Description of the implementation methods

[0035] In the following detailed description, many specific details are set forth to provide a more thorough understanding of the processes. However, it will be apparent to those skilled in the art that the processes can be implemented without necessarily including all of these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0036] In the present description, the different embodiments presented can be implemented separately or in combination with each other, without limitation of combinations when this is technically feasible. Terminology

[0037] It is specified that, throughout this description, the expression "between ... and ..." should be understood as including the limits mentioned, unless otherwise specified.

[0038] In this description, the term "include" is synonymous with "comprise," "include," and "contain," and is inclusive or open-ended and does not exclude other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist."

[0039] Furthermore, when used in this description, and unless otherwise indicated, the terms "essentially" or "approximately" or "about" in relation to a reference value correspond to an approximation of ± 10%, preferably ± 5%, most preferably ± 2%, or even more preferably ± 1% of that reference value, which may be a temperature, a pressure, a distance, a speed, a flow rate, a content of compound(s), etc.

[0040] In this description, the different parameter ranges for a step Data such as pressure ranges and temperature ranges can be used alone or in combination. For example, in the context of the present invention, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values.

[0041] According to the present invention, the pressures are absolute pressures, also noted as abs., and are given in absolute MPa (or abs. MPa), unless otherwise indicated.

[0042] In this description, the term "hydroconversion / hydrotreating catalyst" means a porous supported catalyst used in a bubbling bed hydroconversion process or a hydrotreating process, particularly a fixed bed hydrotreating process, of a hydrocarbon feedstock. In the remainder of this description, the term "catalyst" refers to such a hydroconversion / hydrotreating 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 cobalt, nickel, tungsten, molybdenum sulfides, 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. One such catalyst is detailed later in the description.

[0043] In this description, the term "hydroconversion," also referred to by the acronyms "HDC" and "HCK," and by the term "hydrocracking" more commonly used when the feed in question is a light feed, refers to a process whose main purpose is to reduce the boiling point range of a hydrocarbon feed 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 feed is converted into products having lower boiling point ranges than those of the original feed. 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 through the cleavage of carbon-carbon bonds, in the presence of hydrogen to saturate the broken bonds and aromatic rings. The mechanism by which hydroconversion occurs typically involves the formation of hydrocarbon free radicals during fragmentation, mainly through thermal cracking, followed by the capping of the free radical terminations or fragments with hydrogen in the presence of active catalyst sites. Of course, during a process... In addition to hydroconversion, other reactions typically associated with hydrotreating may occur, such as, among others, the removal of sulfur or nitrogen from the feed, or the saturation of olefins, and as more broadly defined below.

[0044] The term "hydrotreating," commonly referred to as "HDT," describes a gentler operation than hydroconversion, the main purpose of which is to remove impurities such as sulfur, nitrogen, oxygen, halides, and trace metals from the feed, and to saturate olefins and / or stabilize hydrocarbon free radicals by causing them to react with hydrogen rather than allowing them to react with themselves. The main purpose is not to change the boiling point range of the feed. Thus, hydrotreating includes hydrodesulfurization reactions (commonly called "HDS"), hydrodeazotation reactions (commonly called "HDN") and hydrodemetallation reactions (commonly called "HDM"), accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydrodeasphalting and Conradson carbon reduction reactions.Hydrotreating is most often carried out using a fixed-bed reactor, although other reactors can also be used for hydrotreating, for example, a bubbling-bed hydrotreating reactor. In the field of fuel production for other applications, hydrotreating can thus bring hydrocarbons to the required specifications (sulfur content, aromatics, etc.) for a given application (automotive fuel, gasoline or diesel, heating oil, etc.). Automotive standards, in particular, have imposed a very significant reduction in sulfur in diesel and gasoline fuels, and hydrotreating makes it possible to bring these products to the required specifications. Hydrotreating improves hydrocarbon quality by reducing the content of certain compounds considered impurities. It can also reduce the content of aromatic hydrocarbons through hydrogenation, thereby improving the cetane number of fuels. Hydrotreating processes can also produce small quantities of fuel gas and light fractions such as LPG (Liquefied Petroleum Gas) and naphtha.

[0045] Where standards are cited in this description, they refer to the most recent published versions at the date of filing of this application, unless otherwise specified.

[0046] In this description, the term “extraction” with reference to metallic contaminants from the catalyst is synonymous with the term “leaching,” unless otherwise specified. The terms “extraction” and “leaching” are thus understood in the This description describes the process of extracting one or more metals from a solid (worn catalyst) by dissolving them in a liquid (extraction or leaching solution).

[0047] In this description, the terms "metallic contaminants" or "contaminating metals" refer interchangeably to metals considered as contaminants that have been deposited on the catalyst during its use, typically in a hydroconversion or hydrotreating process, preferably hydroconversion, and that originate from the hydrocarbon feedstock. The spent catalyst according to the present invention thus contains metallic contaminants including at least nickel and vanadium. Therefore, in this description, the terms "vanadium contaminant" or "contaminating vanadium" will specifically refer to the vanadium introduced by the feedstock and deposited on the catalyst during its use.Similarly, the terms "contaminating nickel" or "contaminating nickel" refer to the nickel supplied by the feedstock, which in the present invention must be distinguished from the nickel that may be contained in the active phase of the spent catalyst. Unlike the nickel in the active phase, which is distributed homogeneously throughout the catalyst, contaminating nickel is generally deposited only on the surface of the catalyst.

[0048] Reference may also be made in this description to the "metal deposit rate" to designate an average metal deposition rate from the feed on the catalyst during the hydroconversion or hydrotreating step, and corresponds to the total mass of metals from the feed deposited in / on the catalyst during hydroconversion / hydrotreating divided by the total mass of fresh catalyst (the fresh catalyst comprising the support and the active phase). The metal deposit rate 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 mass percentage contents of catalyst compounds, this refers to the total mass of the fresh catalyst in its oxide (non-sulfurized) form. The rate of metals deposited can be mathematically estimated from the metal content in the hydrocarbon feed, the total mass of hydrocarbon feed treated, the performance in total demetallation of the feed (HDM reactions and / or deposits), the inventory (quantity) of catalyst 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 the spent catalyst is taken, washed in the laboratory using a Soxhlet extractor with a solvent such as toluene to extract the liquid products without extracting the metals, and then dried, typically in an atmospheric or vacuum oven, at a temperature sufficient to The solvent is evaporated, 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. Preferably, the spent catalyst sample, washed and dried, is regenerated, typically in an oven, for example at a temperature of around 500°C, to remove the coke. In the laboratory, regeneration is typically carried out in an air furnace, preferably with a slow temperature increase (for example with one or more temperature steps) to avoid the formation of hot spots. The regenerated catalyst sample is then ground before analysis. Elemental analyses, typically using inductively coupled plasma (ICP) spectrometry or X-ray fluorescence (XRF) spectrometry, allow for the quantification of the content of various catalyst elements. These include aluminum and molybdenum in the most typical hydroconversion catalysts, as well as metals deposited during hydroconversion / hydrotreating, such as vanadium and nickel in the most typical petroleum feedstocks processed in a hydroconversion process, and any other elements. The metal deposition rate (average metal deposition rate from the feedstock onto the catalyst during the hydroconversion / hydrotreating step) for the analyzed catalyst sample can be estimated by considering the known composition of the fresh catalyst. It should be noted that in the spent catalyst sample withdrawn from a hydroconversion reactor, there is an age distribution of the catalyst grains linked to a variable residence time in the reactor, depending on the grains, typical of hydroconversion processes using a bubbling bed, for example. Consequently, there is also a distribution of deposited metals, since the amount of metal deposited during 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 metal deposit rate of the spent catalyst withdrawn from a hydroconversion reactor refers to the average mass of metals deposited relative to the estimated total mass of fresh catalyst in the analyzed catalyst sample.

[0049] 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, 81st edition, 2000-2001). For example, group VIII (or VIIIB) according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUP AC classification, and group VIB to the metals in column 6.

[0050] Elemental analyses, typically by plasma coupling spectrometry Inductively coupled plasma (ICP) or X-ray fluorescence spectrometry, more commonly known as X-ray fluorescence (FX), allows the content of the different elements of the extraction solution and the catalyst pretreated at 550 °C under air to be quantified.

[0051] Surprisingly, the inventors have shown that the use of a specific sulfuric acid-based solution, which combines sulfuric acid with at least one alcohol, allows for the efficient extraction of metallic contaminants such as vanadium and nickel from spent hydroconversion / hydrotreating catalysts, thus enabling the recycling of the decontaminated catalyst in a hydroconversion or hydrotreating process. Process for decontaminating used catalysts

[0052] According to a first aspect, the present invention relates to a decontamination process for 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 process includes 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 hydroconversion or hydrotreating process of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel. The spent catalyst, depleted of vanadium and nickel contaminants, is also referred to in this description as a "decontaminated catalyst". The worn catalytic converter

[0053] 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.

[0054] The spent catalyst is decontaminated during the metallic 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 originates.

[0055] The spent catalyst preferably originates from a bubbling bed reactor in a hydroconversion section of a hydroconversion process, or from a reactor, preferably a fixed bed reactor, in a hydrotreating section of a hydrotreating process, said processes treating a hydrocarbon feedstock containing metals including vanadium and nickel.

[0056] Conventional hydroconversion / hydrotreating 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 hydrotreating catalysts. The preparation of these catalysts generally includes an impregnation step of the metals (and phosphorus for conventional hydrotreating 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 hydrotreating reaction, these catalysts are also generally subjected to sulfidation.

[0057] The addition of an organic additive, particularly to hydrotreating catalysts to improve their activity, is also known, especially for catalysts prepared by impregnation followed by drying without subsequent calcination. These catalysts are often called "additized dried catalysts".

[0058] The catalysts used for the hydroconversion of certain (typically light) feedstocks, generally called "hydrocracking," are classically of the bifunctional type, that is, combining an acid function with a hydrogenating function. The acid function is provided by supports with large surface areas (generally 150 to 800 m².g⁻¹) exhibiting significant acidity, such as halogenated aluminas (particularly chlorinated or fluorinated), 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 equilibrium between the two acid and hydrogenating functions governs the activity and selectivity of the catalyst.

[0059] During its operation in a hydrotreating or hydroconversion process, the catalyst becomes deactivated by the 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. The deposited metals can interact with the catalyst's active sites, blocking them and thus reducing the catalyst's ability to catalyze reactions, leading to progressive catalyst deactivation. The nature of the deposited metals depends on the nature of the metals present in the feedstock of the hydroconversion process. Coke deposits can also deactivate the catalyst's active sites, or clog the pores and thus make the active sites less accessible to reagents. Beyond a certain period, its replacement is therefore necessary. The quantity of metals and coke deposited depends, as does the nature of the metals, on the nature of the hydrocarbon feedstock. In the case of boiling bed hydroconversion, the amount of metals and coke deposited during hydroconversion varies from one catalyst grain to another and depends on the residence time of the catalyst grain in the hydroconversion reactor. The metal deposit rate of the spent catalyst, particularly the spent hydroconversion catalyst, can range from 5% to 150% by weight relative to the weight of fresh catalyst.

[0060] 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 (contamination nickel and vanadium).

[0061] The source catalyst, i.e. the spent catalyst, is therefore typically a hydroconversion or hydrotreating catalyst, preferably a hydroconversion catalyst, which is described in detail below, after the following description of the hydrocarbon feed used in such hydroconversion / hydrotreating processes, and which is the source of the catalyst contamination. The hydrocarbon charge

[0062] The hydrocarbon feedstock targeted by hydroconversion and / or hydrotreatment can be of different natures. In particular, the feedstock may be of fossil origin or derived from the conversion of biomass or waste, either alone or in mixtures. 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, with nickel and vanadium being the most abundant metals in heavy feedstocks.

[0063] The fossil fuel feedstock may include, in particular, a fraction derived from coal or hydrocarbons produced from natural gas, possibly in a mixture. It may also consist of petroleum or heavy petroleum or synthetic fractions, for example kerosene, diesel fuel, or distillates obtained by atmospheric and vacuum distillation to produce kerosene, diesel fuel, or vacuum distillate, which can be used either in a storage unit receiving products of the same type (a "pool") or in a downstream unit such as a catalytic cracking unit where the fractions sent are "cracked" to produce shorter-chain hydrocarbons.

[0064] The fossil-based feedstocks used in a hydrotreating process, in more detail, are for example gasoline, diesel fuel, vacuum diesel fuel, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuel oils, oils, waxes and paraffins, oils used materials, residues or deasphalted crudes, feedstocks from thermal or catalytic conversion processes, taken alone or in mixtures. Fossil-based feedstocks used in a hydroconversion process are typically heavy feedstocks containing at least 50% by weight of a component with 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. More specifically, these feedstocks may comprise, or be composed of, any of the following, alone or in mixtures: crude oil, synthetic crude oil, coal tar, bitumen from oil sands, heavy oil from oil shale, atmospheric residue, or vacuum residue from the atmospheric or vacuum distillation of crude oil.an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion, hydrotreating, hydrocracking, hydroconversion, or direct coal liquefaction unit (e.g., operated using the H-Coal® process), a vacuum distillate obtained directly from crude oil or a cut from a fluidized bed catalytic cracking (FCC) unit, a hydrocracking, hydroconversion, coking, or visbreaking unit, a vacuum distillate from direct coal liquefaction, aromatic cuts extracted from a lubricant production unit, deasphalted oil (DAO), or asphalt originating from a de-asphalting unit. The aforementioned feedstocks of the type vacuum distillates, aromatic cuts and deasphalted oils for a hydroconversion process may enter into the composition of the feed of said process preferably in a minority with another type of feedstock mentioned above. Preferably, the fossil-based feedstocks used in a hydroconversion process include, and may consist of, a vacuum residue from the vacuum distillation of crude oil.

[0065] The feedstock resulting from biomass conversion may advantageously be selected from vegetable oils, algae or algal oils, fish oils, used cooking 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, wholly or partially, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut (coconut oil and oil of Copra), castor, cotton, peanut, flax, crambe, jatropha, and all oils derived from plants obtained through genetic modification or hybridization, such as sunflower or rapeseed, are all suitable sources. This list is not exhaustive. Animal fats are advantageously chosen from lard and fats composed of residues from the food industry or from the catering industry. Frying oils, various animal oils such as fish oil, tallow, and lard can also be used. Feed from biomass conversion can also advantageously be chosen from methyl esters of fatty acids of vegetable and / or animal origin, or from methyl esters of fatty acids from used edible vegetable oils. In a bubbling bed hydroconversion process, vegetable and / or animal oils or fats are preferably used as a co-feed in combination with another heavy liquid feed of hydrocarbons.

[0066] The feedstock resulting from biomass conversion can also be selected from feedstocks obtained from thermal or catalytic biomass conversion processes, such as oils produced from biomass, particularly lignocellulosic biomass, using various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, including 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). The feedstock from biomass conversion can also advantageously be chosen from feedstocks from the paper industry.

[0067] The feedstock resulting from waste conversion can be a pyrolysis oil derived from plastics, tires, or solid recovered fuels (SRF). The plastics are typically production by-products and / or waste (e.g., household, building, electrical and electronic equipment waste), and preferably comprise alkene, diene, vinyl, styrenic, polyester, and / or polyamide polymers, and more preferably polyolefins, such as polyethylene (PE), polypropylene (PP), or ethylene-propylene copolymers. These oils are obtained by thermal or catalytic pyrolysis treatment, or prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen). In a bubbling bed hydroconversion process, it may also be considered to use a feedstock consisting of solid plastic waste in combination with a heavy liquid feedstock, after specific conditioning of the co- charges.

[0068] The heavy fossil-based fillers 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. The metal content may be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight. For example, the combined 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. 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. 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. The content of C7 asphaltenes (heptane-insoluble compounds according to ASTM D 6560, which also corresponds to NF T60-115) can be as low as 1% by weight and is often greater than or equal to 3% by weight (except for feedstock consisting primarily of DAO). C7 asphaltenes are known to inhibit the conversion of residual cuttings, both through their ability to form heavy hydrocarbon residues, commonly called coke, and through their tendency to produce sediments that can severely limit the operability of hydroconversion units. The Conradson carbon content can 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 assessment of the amount of carbon residue produced after pyrolysis under standard temperature and pressure conditions. These contents are expressed as a percentage by weight of the total weight of the hydrocarbon filler.

[0069] All the fillers mentioned are liquid under the operating conditions of T hydroconversion / T hydrotreatment. Composition of the spent catalyst

[0070] According to the present invention, the term "spent catalyst" or "source catalyst" refers to the catalyst from which metallic contaminants are to be extracted, which is a catalyst that is at least partially spent, that is to say, one that has already been used in production, particularly in hydroconversion or hydrotreating plants. The term also includes a collection mass that is at least partially spent.

[0071] Although the present invention relates to the recycling of catalysts from hydroconversion or hydrotreating units of hydrocarbons, 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, hydrotreating catalysts for residues (for example carried out in a boiling bed) or Fischer-Tropsch catalysts.

[0072] The spent catalyst is preferably derived from a fresh hydroconversion / hydrotreating catalyst, i.e. new (never used), described below.

[0073] The fresh catalyst, and the spent catalyst derived 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.

[0074] The spent catalyst also includes, as contaminants, at least coke, vanadium, and nickel. It may also, but is not limited to, include sulfur and other contaminants as described below.

[0075] The porous support based on oxide(s) of the fresh catalyst and of the spent catalyst derived from the fresh catalyst is advantageously a support comprising, and possibly consisting of, silica, alumina, amorphous silica-alumina, titanium dioxide, magnesium oxides, clay, boron oxide, zirconia, or combinations of these materials, preferably comprising, and possibly consisting of, silica, alumina, amorphous silica-alumina, titanium dioxide, or combinations thereof. In one embodiment, the catalyst support is essentially composed of alumina, silica, or silica-alumina. Most preferably, the porous support is essentially composed of alumina. Alumina can advantageously be in any form known to those skilled in the art.For example, the alumina is chosen from the group consisting of alpha, rho, chi, kappa, eta, gamma, theta, and delta aluminas, preferably gamma, theta, and delta aluminas, and even more preferably 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.

[0076] These materials are porous refractory oxides in which the metals of the active phase are classically dispersed.

[0077] 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 A zeolite material, which can notably provide a cracking function in addition to the hydro-dehydrogenating function provided by the metals of the active phase, is used. This zeolite material, together with the refractory oxide, forms the porous support within which the metals of the active phase are dispersed. The zeolite material content of 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 associated preparation methods can be incorporated. The said zeolitic material may be a zeolite selected from zeolites of structure MFI, FAU, BEA, ISV, IWR, IWW, MEI, UWY, preferably MFI, FAU and BEA, more preferably FAU and BEAU, and preferably selected from zeolites ZSM-5, beta and / or Y, and even more preferably the USY and / or beta zeolite.Regarding the zeolites mentioned in this description, those skilled in the art can refer to the book "Atlas of zeolite framework types", 6th revised Edition, 2007, Ch. Baerlocher, WM Meier, DH Oison for their characteristics.

[0078] According to one or more embodiments, particularly for hydrotreating catalysts, the oxide-based porous support 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 ASTM D4284-92 with a wetting angle of 140°, for example using a Microméritics™ Autopore III™ instrument.

[0079] According to one or more embodiments, particularly for hydrotreating catalysts, the specific surface area of ​​the oxide support is advantageously between 5 and 400 m².g*, preferably between 10 and 350 mkg¹, more preferably between 40 and 350 mkg¹. The specific surface area is determined in the present invention by the BET method according to ASTM D3663.

[0080] The active phase of the fresh catalyst, and of the spent catalyst derived from the fresh catalyst, comprises at least one metal from Group VIB and / or at least one metal from Group VIII. The Group VIB metal present in the active phase is preferably chosen from molybdenum and tungsten, or a mixture of these two elements. The Group VIII metal present in the active phase is preferably chosen from cobalt, nickel, and a mixture of these two elements. The active phase of the catalyst is preferably chosen from the group formed by the combination of nickel-molybdenum, cobalt-molybdenum, nickel-cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten, and nickel-cobalt-tungsten.

[0081] 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%. weight. When the metal is cobalt or nickel, the metal content is expressed in CoO and NiO respectively.

[0082] The content of metal of group VIB, e.g. molybdenum, is advantageously between 0% and 30% expressed by weight of oxide of the metal (e.g. molybdenum trioxide MoO3), preferably between 1% and 30%, and preferably between 4% and 20% by weight.

[0083] Metal contents are expressed as a percentage by weight of metal oxide relative to the weight of the fresh catalyst.

[0084] The fresh catalyst, and the spent catalyst derived from the fresh catalyst, may also comprise at least one dopant element selected 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. The molar ratio of phosphorus added as a dopant during the manufacture of the fresh catalyst to the element of group VIB 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 most preferably between 0.15 and 0.6.

[0085] The fresh catalyst, and the spent catalyst derived from the fresh catalyst, may contain 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 most preferably between 4 and 10% by weight. The sulfur content is measured by elemental analysis according to ASTM D5373. The sulfur may originate from the hydrocarbon feedstock and / or from a sulfurization step of the fresh catalyst and / or from a sulfur compound added to the feedstock for the purpose of in-situ sulfurization of the fresh catalyst for its use in the hydroconversion / hydrotreating process. The sulfurization step generally required for the use of the catalyst consists of activating the catalyst by transforming, at least partially, the oxide phase into a sulfur-reducing medium.This sulfuration activation treatment 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.

[0086] 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, of preferably chosen from molybdenum and tungsten, preferably molybdenum; - a porous oxide support(s), serving as a support for said metal(s) forming the active phase, comprising, and preferably consisting essentially of, silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia or their combinations, and preferably alumina.

[0087] These hydroconversion catalysts are well known to those skilled in the art.

[0088] The fresh catalyst, and the spent catalyst derived from the fresh catalyst, are advantageously used in the form of extrudates, beads, pellets, or irregular, non-spherical 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 can be characterized by means of the equivalent diameter.The equivalent diameter is defined as six times the ratio between the particle volume and the external surface area of ​​the particle. The supported porous catalyst, used in the form of extrudates, beads or other shapes, thus has an equivalent diameter between 0.4 mm and 4.4 mm.

[0089] The spent catalyst comprises coke. It should be noted that the term "coke" in this application refers to a hydrocarbon-based substance deposited on the surface of the catalyst during its use, which is highly cyclized and condensed and has an appearance similar to graphite.

[0090] The coke content, expressed as a percentage by weight of the carbon element, can be between 2% and 90% by weight relative to the total weight of the fresh catalyst, preferably between 5% and 70% by weight, and preferably between 5% and 50% by weight. In the case of spent catalysts from hydrotreating units, which generally process lighter feeds than those sent to a boiling bed hydroconversion process and are less prone to coke formation, the coke content of the spent catalyst can 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 boiling bed hydroconversion units, the coke content can range from 5% to over 20% by weight, generally up to 50% by weight, or even up to 70% or 90% by weight relative to the total weight of the fresh catalyst. The coke content is determined according to ASTM D5373.

[0091] 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.

[0092] The spent catalyst is contaminated with nickel from the hydrocarbon feed. 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% wt and 150% wt, and preferably less than 0.1% wt and 80% wt relative to the total weight of the fresh catalyst.

[0093] 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 lower, between 0.1% by weight and 80% by weight relative to the total weight of the fresh catalyst.

[0094] 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.

[0095] 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 most preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0096] Preferably, the titanium content of the spent catalyst is between 0 and 0.5% by weight, preferably between 0.01% and 0.5% by weight and most preferably less than between 0.02% by weight and 0.2% by weight relative to the total weight of the fresh catalyst.

[0097] 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, most preferably, between 0.2% and 50% by weight relative to the total weight of the fresh catalyst.

[0098] 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 most preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0099] 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 most preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0100] 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 most preferably between 0.2% by weight and 60% by weight relative to the total weight of the fresh catalyst.

[0101] Preferably, the chlorine content of the spent catalyst is between 0 and 0.5 wt%, preferably between 0.01 wt% and 0.5 wt%, and in a very preferred between 0.02% by weight and 0.2% by weight relative to the total weight of the fresh catalyst.

[0102] The spent catalyst from a hydrotreating process of a medium distillate feed (diesel, kerosene) or a naphtha feed 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 feed. The vanadium and nickel contamination contents of a spent catalyst from a hydrotreating process of a medium distillate feed (diesel, kerosene) or a naphtha feed are generally less than 10,000 ppm wt. nickel and less than 20,000 ppm wt. vanadium relative to the weight of the spent catalyst. Pretreatments (optional)

[0103] The spent catalyst may be subjected to at least one pretreatment step prior to the metallic contaminant extraction step. The optional pretreatment step consists of preparing the spent catalyst for improved metallic contaminant extraction and aims in particular to remove all or part of the residues of the hydrocarbon feedstock or one or more of the impurities that may be contained in said spent catalyst before the metallic contaminant extraction step, by any method known to those skilled in the art. The pretreatment step may be chosen from oil removal, water washing, and drying. These preliminary treatments aim to make the metallic contaminant extraction step more efficient, through physical or chemical treatments. Oil removal or water washing serve the same purpose by improving / increasing the contact between the extraction solution and the contaminants contained in the source catalyst. - Degreasing

[0104] The unloading of the spent catalyst from a reactor in a hydrotreating and / or hydroconversion unit is preferably followed by a de-oiling step. This step is essentially aimed at removing hydrocarbon charge residues from the catalyst particles. The de-oiling step generally comprises contacting the spent catalyst with a stream of inert gas (i.e., essentially free of oxygen), for example in a nitrogen or similar atmosphere, at a temperature between 300°C and 400°C, preferably between 300°C and 350°C. The inert gas flow rate is preferably 5 to 150 NL.h⁻¹ (flow rate per unit volume of catalyst), for a duration preferably between 3 and 7 hours. Alternatively, the oil removal step can be carried out by contact with an oil removal solvent, preferably light hydrocarbons, for example by steam treatment or any other similar process.The hydrocarbon degreasing solvent is preferably chosen from the list consisting of a gasoline, a diesel, and a compound. aromatic, preferably toluene. - Drying

[0105] 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.

[0106] The drying gas is preferably an inert gas such as nitrogen. - Wash with water

[0107] The used catalyst, possibly de-oiled, can undergo a water washing step.

[0108] The volume of water used in this washing step is advantageously greater than the total porous volume of the spent catalyst. This volume may, in particular, be within a range of 2 to 20 times the total porous volume of the spent catalyst, preferably between 5 and 10 times said porous volume.

[0109] The washing step can be carried out at any suitable temperature, for example between 5°C and 150°C, preferably between ambient temperature (approximately 20°C) and 70°C.

[0110] During the washing step, it is advantageous to stir the spent catalyst to ensure effective washing. The washing step can be carried out continuously or batchwise, with batch mode being preferred as it limits the amount of water used. The washing step can be carried out in any type of solid / liquid extractor or industrial mixer. Metallic contaminant extraction stage

[0111] According to an essential aspect of the process according to the invention, an extraction step is carried out to remove at least some of the metallic 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 a decontaminated catalyst, which is recyclable in a hydroconversion and / or hydrotreating process for hydrocarbon feedstocks. A liquid extract comprising at least vanadium and nickel is also obtained.

[0112] The main objective of this extraction step is to extract metallic contaminants, including vanadium and nickel (contaminant), but also possibly other metallic contaminants from the spent catalyst, while preferably limiting the extraction of the active phase, i.e., the metals of group VIII and / or VIB that constitute the active phase of the catalyst. The limitation of metal extraction from the active phase during this step can be further enhanced by the presence of coke on the catalyst. The spent catalyst, sent to the metal contaminant extraction step, preferably has not undergone prior regeneration to remove coke, in order to benefit from this protective effect of the coke on the active phase. Without being linked to any specific theory, it would appear that the coke present in the catalyst protects the extraction of the active phase, particularly the extraction of the VIB group metal, while the metal contaminants on the catalyst surface are extracted. However, performing a regeneration step upstream of the metal contaminant extraction step does not fall outside the scope of the invention, as detailed below in the description of the regeneration step. Indeed, the extraction of metal contaminants is possible without the presence of coke on the spent catalyst.

[0113] Preferably, said at least one alcohol of the extraction solution is chosen from the list consisting of methanol, ethanol, 1-propanol, 2-propanol (or iso-propanol), 1-butanol, 2-butanol, 2-methyl-1-propanol, / er / 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.

[0114] Preferably, the alcohol in the extraction solution is ethanol.

[0115] 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.

[0116] The extraction solution generally has a pH between 0.1 and 8.5, preferably between 0.5 and 6, preferably between 1 and 4.

[0117] The concentration of sulfuric acid in the extraction solution is preferably defined so that the sulfuric acid / metallic contaminant 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.

[0118] The concentration of sulfuric acid in 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.

[0119] 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.

[0120] The extraction solution is chosen so as to maximize the extraction rate of metallic contaminants which include vanadium and nickel, while preferably limiting the extraction of group VIII and / or VIB metal from the active phase. The selective extraction of metallic contaminants from Group VIII and / or VIB metals can, for example, be expressed through the extraction rates of Metallic contaminants, e.g. nickel and vanadium, relative to those of group VIII and / or VIB metals, or by the mass ratios of extracted vanadium / extracted group VIII (or VIB) metal and extracted nickel / extracted group VIII (or VIB) metal, also called V / VIII, V / VIB, Ni / VIII or Ni / VIB ratios. A high ratio indicates high selectivity, which is desirable (this allows for the extraction of a high concentration of metallic contaminants but little of the active phase).

[0121] 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 allows for a synergistic effect on extraction selectivity; in particular, the use of such a solution allows for the extraction of more vanadium and nickel contamination relative to the extracted Group VIII and / or VIB metal than a solution comprising only sulfuric acid (without alcohol).

[0122] According to one or more embodiments of the invention, the extraction solution may also contain an oxidant to promote metal extraction. Preferably, the oxidant in the extraction solution is hydrogen peroxide. When an oxidant is present, the concentration is generally between 0.1 and 5.0 mol / L.

[0123] The contacting of the spent catalyst with the extraction solution is preferably carried out under the following conditions:

[0124] 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 ambient temperature (approximately 20°C).

[0125] The pressure is generally between atmospheric pressure and 20 bars (2 MPa), in particular between atmospheric pressure and 10 bars (1 MPa).

[0126] The duration of contact per extraction step is generally between 1 minute and 20 hours, preferably between 5 minutes and 300 minutes, and preferably between 5 minutes and 120 minutes.

[0127] Preferably, this extraction step is carried out by contacting the spent catalyst with a volume of said solution between 1.5 and 60 times the volume of the spent catalyst. Preferably, the volume of said solution is between 2 and 30 times the volume of the source catalyst, and more preferably between 2 and 20 times the volume of the spent catalyst, and particularly preferably between 3 and 10 times the volume of the spent catalyst.

[0128] According to the present invention, "extraction" is understood to mean that there is an extraction step, but the extraction can be carried out by an extraction operation or a plurality of successive extraction operations.

[0129] All contact methods, whether single-step or multi-step following a co-current, counter-current, or cross-current mode, are possible for implementing the continuous extraction step. The extraction step includes contacting the extraction solution with the spent catalyst, followed by a solid / liquid separation step to obtain, on the one hand, a leached catalyst depleted in contaminants but containing most of the active phase, and, on the other hand, the extraction solution enriched in contaminants and containing as little of the extracted active phase as possible.

[0130] The contacting of the extraction solution with the spent catalyst can be done by any method known to those skilled in the art, for example by suspending the spent catalyst in the extraction solution by means of a rotary agitator or by fluidization, or by percolating the extraction solution through a fixed bed containing the spent catalyst.

[0131] Liquid / solid separation can be achieved by any method known to those skilled in the art, for example by sedimentation, filtration, draining, for example by gravity, and / or by centrifugation.

[0132] The extraction step thus makes it possible to extract most of the most problematic metallic contaminants, vanadium and nickel. This extraction step also makes it possible to extract other contaminants, such as iron, titanium, silicon, calcium, sodium, potassium, and to a lesser extent arsenic.

[0133] The extraction rate of vanadium, nickel (from contamination), iron, titanium, silicon, calcium, sodium and potassium is generally between 30% and 100%, preferably between 50% and 100%, preferably between 70% and 100%.

[0134] The arsenic extraction rate is generally less than 20%, preferably less than 10%, preferably less than 5%.

[0135] Although not desired, this extraction step may also extract a minor part of the active phase, as well as a minor part of phosphorus (possibly present in the spent catalyst) and alumina (from the support) possibly present in the spent catalyst.

[0136] The extraction rate of the group VIII metal from the active phase is generally between 0% and 10%, preferably between 0% and 5%, preferably between 0% and 3%.

[0137] The extraction rate of the metal from group VIB of the active phase is generally between 0% and 10%, preferably between 0% and 5%, preferably between 0% and 3%.

[0138] The extraction rate of phosphorus and aluminum is generally between 0% and 10%, preferably between 0% and 5%, preferably between 0% and 3%.

[0139] The extraction rate corresponds to the mass of the metal / metals extracted in the extraction solution relative to the mass of metal / metals initially present on the spent catalyst.

[0140] At the end of the extraction step, on the one hand, a leached catalyst is obtained, depleted in contaminants, in particular in vanadium and nickel (from contamination) but still containing a major part of the active phase.

[0141] 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 streams of metals which can be reused for other applications (metallurgy, preparation of catalysts, etc.), and a solution comprising sulfuric acid and / or alcohol recyclable to the extraction step to form part of the extraction solution. Regeneration step (optional)

[0142] Preferably, the spent catalyst decontamination process according to the invention may include a regeneration step to remove all or part of the coke, sulfur and / or chlorine from the spent catalyst, as detailed below.

[0143] The regeneration step can be carried out upstream of the metallic contaminant extraction step, typically after one or more pretreatment steps such as oil removal followed by optional water washing and drying of the spent catalyst. Such a regeneration step of 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 can, by removing or reducing the amount of coke and other contaminants such as sulfur compounds or chlorine, improve / increase the contact between the extraction solution and the metals to be extracted contained in the spent catalyst.

[0144] Preferably, when a regeneration step is desired, it is carried out downstream of the metallic contaminant extraction step, on the decontaminated catalyst. Such a regeneration step of the spent catalyst downstream of the extraction step proceeds by removing at least a portion of the coke of said catalyst depleted in vanadium and nickel contaminants (decontaminated catalyst), preferably by combustion, to form a regenerated decontaminated catalyst, which is therefore a regenerated spent catalyst depleted in vanadium and nickel contaminants. In this way, the coke present in the metallic contaminant extraction step appears to advantageously protect the active phase of the catalyst during the metallic contaminant extraction step, so as to limit the dissolution of metals from the active phase of the catalyst and the resulting loss of catalyst activity, as already explained above. high.

[0145] According to one or more embodiments, the process may include a regeneration step upstream of the metallic contaminant extraction step and a regeneration step downstream of the metallic contaminant extraction step.

[0146] The regeneration step of the spent or decontaminated catalyst is a catalyst regeneration step aimed at removing at least some, and preferably essentially all, of the coke from the spent catalyst. Sulfur and chlorinated compounds can also be removed in this step. Advantageously, this is a thermal regeneration involving 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.

[0147] The thermal regeneration of a catalyst by combustion is known to those skilled in the art. This step consists of carrying out a controlled combustion of the catalyst's coke deposits. It allows the restoration of some of the catalyst's active sites by eliminating the coke that deactivates the sites, or limits or blocks the access of reactants by clogging the pores. During the regeneration stage, other compounds may undergo oxidation, with sulfur or nitrogen compounds potentially forming SOx and NOx.

[0148] According to one or more embodiments, the regeneration step includes combustion by bringing said spent catalyst or decontaminated catalyst into contact with a regeneration gas stream containing oxygen, at a temperature between 250°C and 550°C, preferably between 300°C and 500°C. In particular, according to one or more embodiments, when regeneration is carried out on the spent catalyst upstream of the extraction step, the temperature used during regeneration is between 250°C and 450°C, preferably between 300°C and 400°C, notably to control coke removal and, in particular, to retain some of it on the catalyst, which can thus improve performance in the downstream extraction step by a protective effect on the active phase as described above. According to one or more embodiments, when regeneration is carried out on the spent catalyst upstream of the extraction step, the temperature used during regeneration is between 320°C and 550°C, preferably between 360°C and 500°C. When regeneration is carried out downstream of the extraction step, on the decontaminated catalyst from the extraction step, the temperature operated during regeneration is preferably between 320°C and 550°C, preferably between 360°C and 500°C.

[0149] The regeneration gas flow preferably comprises air.

[0150] 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.

[0151] 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 the source catalyst), more preferably from 30 to 1000 NL.h1, and particularly preferably from 40 to 500 NL.h*.

[0152] The regeneration by combustion step can be implemented by any type of equipment known to those skilled in the art, for example including one or more combustion reactors which may be furnaces, including rotary furnaces and furnaces with moving belts, horizontal bed reactors with a propeller for advancing and homogenizing the catalyst, vibro-fluidizing 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. Typical stay times are 1 to 5 hours, preferably 2 to 5 hours, more preferably 2.5 to 5 hours, and particularly preferred 3 to 5 hours.

[0153] During regeneration by combustion, the regeneration gas stream containing oxygen comes into contact with the spent catalyst, causing the 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.

[0154] Once regeneration is complete, the regeneration gas flow is stopped.

[0155] The regeneration step can be carried out remotely from the unit for extracting metallic contaminants, or from the hydroconversion or hydrotreating unit from which the spent catalyst originates, 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 step for extracting metallic contaminants, or even with the hydroconversion or hydrotreating process, i.e., not remotely from the unit for extracting metallic contaminants. talliques, or not delocalised with respect to the hydroconversion or hydrotreatment unit which can also be referred to in this case as in-situ regeneration.

[0156] Preferably, the regeneration step is carried out discontinuously (also called "batch") and at a frequency defined according to the desired catalyst management.

[0157] A discontinuous (batch) implementation of the regeneration step, whether in-situ or ex-situ, may require the use of buffer tanks for the spent catalyst withdrawn and / or the regenerated catalyst which will be recycled in the hydroconversion / hydrotreating step.

[0158] Advantageously, the regenerated catalyst 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.

[0159] The regenerated spent catalyst or the regenerated decontaminated catalyst is composed of the porous oxide-based support(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 phosphorus from the spent catalyst. The regenerated spent catalyst or the regenerated decontaminated catalyst contains substantially the same content of group VIB and / or VIII metal as the spent catalyst.

[0160] The regenerated spent catalyst or the regenerated decontaminated catalyst is characterized by a specific surface area of ​​between 20 and 600 m2 / g, preferably between 30 and 400 m2 / g, preferably between 40 and 360 m2 / g.

[0161] The pore volume of the regenerated or regenerated decontaminated spent catalyst is generally between 0.1 cmVg and 1.6 cmVg, preferably between 0.2 cmVg and 1.3 cmVg.

[0162] 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.

[0163] Preferably, the regenerated, decontaminated catalyst is not or only slightly contaminated, i.e., it contains 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 (other than 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 weight of silicon, less than 500 ppm weight of calcium, less than 1000 ppm of sodium, less than 500 ppm weight of potassium and less than 100 ppm weight of chlorine relative to the weight of the regenerated decontaminated catalyst. Post-processing (optional)

[0164] The decontaminated catalyst from the extraction step, optionally regenerated upstream or downstream of the extraction step, can undergo at least one post-treatment step chosen from oil removal, water washing, and drying, preferably water washing 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.

[0165] The water washing and drying steps are similar to those described in the optional pretreatments, and their description is not repeated here. hydroconversion process

[0166] A recycling of the decontaminated catalyst is proposed by the present invention, with a view to recycling to hydroconversion / hydrotreating, and in particular to a hydroconversion step in a bubbling bed reactor as a daily supplement of hydroconversion catalyst, possibly in addition to fresh (new) catalyst to complete the supplement.

[0167] According to one aspect, the present invention relates to a hydroconversion process comprising: - a hydroconversion step of a hydrocarbon feed containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in a bubbling bed in the presence of hydrogen and at least one hydroconversion catalyst and;

[0168] - a step of withdrawing a stream of said catalyst from said hydroconversion reactor of used hydroconversion and of introduction into said hydroconversion reactor of a top-up comprising a recycled hydroconversion catalyst stream, preferably in combination with a fresh hydroconversion catalyst stream;

[0169] - a decontamination step of said spent catalyst stream withdrawn by the process of decontamination 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.

[0170] The catalyst decontamination process has been extensively described above and is not repeated here.

[0171] The principle of implementing a hydroconversion process according to the invention is described below:

[0172] A hydrocarbon feed containing metals is sent to a stage hydroconversion in a hydroconversion section comprising at least one hydroconversion reactor operating in a bubbling bed in the presence of hydrogen and a porous supported hydroconversion catalyst. In said hydroconversion reactor is introduced a supplement comprising a recycled hydroconversion catalyst stream, possibly in combination with fresh catalyst partially compensating for a spent hydroconversion catalyst stream withdrawn from the reactor.

[0173] 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 coke removal, the spent catalyst for recycling as a supplement in the hydroconversion reactor.

[0174] This recycling thus makes it possible to reduce the supply of fresh catalyst compared to a classic scheme without recycling of part of the used catalyst withdrawn and regenerated. Charge

[0175] The charge, in particular the charge used in a hydroconversion process, has been described above in relation to the process of decontaminating the spent catalyst, and its description is not repeated here. Hydroconversion stage

[0176] The hydrocarbon feedstock is introduced into a hydroconversion reactor in the hydroconversion section, together with hydrogen (flow not shown). Said reactor includes the hydroconversion catalyst.

[0177] Such a reactor is a three-phase reactor containing hydrogen and a catalyst in a fluidized bed called a bubbling bed, and operating with an upward flow of liquid and gas.

[0178] The hydroconversion section comprises one or more bubbling bed reactors 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 bubbling 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 bubbling bed technology", or in chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" of the book "Catalysis by Transition Metal Sulphides", Editions Technip, 2013.Each reactor advantageously includes a recirculation pump which makes it possible to maintain the porous supported solid catalyst in a bubbling bed by continuously recycling at least part of a liquid fraction drawn from the upper part of the reactor and reinjected at the lower part of the reactor.

[0179] The bubbling bed reactor preferably comprises at least one inlet located at The reactor includes an inlet at or near the lower part of the reactor through which the feedstock is introduced along with the hydrogen, and an outlet at or near the upper part of the reactor through which the hydroconverted effluent is removed from the reactor. The reactor further advantageously includes at least one inlet and one outlet for injecting additional catalyst and removing spent catalyst, as described in more detail below in the catalyst removal and replenishment step. The bubbling bed reactor further includes an expanded catalyst zone comprising the catalyst (the bubbling bed). The bubbling bed reactor also includes 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 bubbling bed reactor is continuously recirculated from the upper supported catalyst-free zone to the lower supported catalyst-free zone via a recycle line connected to a boiling pump. Preferably, a funnel-shaped recycle cup is located at the top of the recycle line, 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.

[0180] Because the catalyst is kept agitated by a large amount of liquid recycling, the pressure drop on the reactor remains low and constant, and the reaction exotherms are quickly averaged over the catalytic bed, which is therefore almost isothermal and does not require, for example, the injection of cooling fluxes (“quenches” in English). The use of such bubbling bed reactors also allows operation under more severe conditions than, for example, those encountered in a fixed-bed catalyst reactor, resulting in better overall feed conversion. Another advantage of using bubbling bed reactors is the long cycle time of the hydroconversion unit (without unit shutdown to replace the catalyst(s)), thanks in particular to the catalyst withdrawal and injection system that enables continuous replacement of spent catalyst without stopping the hydroconversion unit, a feature made possible by the operation of this type of reactor.

[0181] An essential aspect of the operation of bubbling bed reactors is indeed the continuous replacement of the hydroconversion catalyst. Catalyst replacement is required in all hydrocarbon feed conversion processes (regardless of the reactor technology used, for example a fixed bed, moving bed, or bubbling fluidized bed reactor), because the catalyst is deactivated mainly by the deposition of metals contained in the feed and by the deposition of coke under the operating conditions of hydroconversion.

[0182] While bubbling bed technology does ultimately increase the time between two shutdowns of the hydroconversion process thanks to the continuous nature of catalyst renewal, compared to other technologies such as fixed bed technologies, it requires the implementation of a continuous catalyst renewal system, with daily removal and replenishment of catalyst. Because the catalyst is very thoroughly mixed in the bubbling bed, after an initial stabilization period, an equilibrium state is reached for the catalyst age distribution and its activity, thus allowing operation under 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 load being processed, and this rate can be different for each hydroconversion reactor if several reactors are used.

[0183] Catalyst renewal thus makes it possible to compensate 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 bubbling bed hydroconversion reactor, a drawback encountered is that the spent catalyst withdrawn consists of a mixture of highly deactivated catalyst, moderately deactivated catalyst, and almost new catalyst, so that the use of the catalyst in bubbling bed hydrotreating reactors is not optimized.

[0184] The hydroconversion step is carried out under conditions that produce a hydroconverted effluent containing the conversion products. In particular, the hydroconverted effluent has a reduced content (compared to the feed) of hydrocarbons with a boiling point of at least 300°C, or at least 350°C, 375°C, 450°C, 500°C, or 540°C, depending on the nature of the feed. This hydroconverted effluent also has a reduced content, compared to the feed, of metals, and / or sulfur, and / or nitrogen, and / or Conradson carbon, and / or asphaltenes, and / or other impurities initially present in the feed, depending on the reactions carried out in the hydroconversion reactor and the composition of the feed. In particular, the said hydroconverted effluent may advantageously have a reduced content, relative to the load, of metals, sulfur, nitrogen, Conradson carbon, and asphaltenes. The hydroconversion step is preferably carried out under an absolute pressure 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 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. The hourly spatial velocity (WH) is preferably between 0.05 h 1 and 10 h 1 (WH relative to the volume of each reactor). The hourly space velocity (WH), also called the hourly volumetric velocity (liquid hourly space velocity "LHSV" or hourly space velocity "HSV" according to Anglo-Saxon terminology), is defined here as the ratio between the hourly volumetric flow rate of the liquid feed (sent to the hydroconversion stage) and the volume of each hydroconversion reactor. According to a preferred implementation, the WH is between 0.1 h₁ and 10 h₁, more preferably between 0.1 h₁ and 5 h₁, even more preferably between 0.15 h₁ and 2 h₂*, and even more preferably between 0.15 h₁ and 1 h₁. According to another implementation, the overall WH, i.e. the liquid feed rate sent to stage b) relative to the volume of all reactors if several hydroconversion reactors are implemented in stage b), is between 0.05 h 1 and 0.09 h 1. The quantity of hydrogen mixed with the feed is preferably between 50 and 5000 normal cubic meters (Nm3) per cubic meter (m3) of liquid feed, preferably between 100 Nm3 / m3 and 2000 Nm3 / m3 and most preferably between 200 Nm3 / m3 and 1000 Nm3 / m3.

[0185] The catalyst, in particular the hydroconversion catalyst, has been described above in relation to the process of decontaminating the spent catalyst, and its description is not repeated here.

[0186] According to one or more embodiments, the hydroconversion process includes a second hydroconversion step in at least a second bubbling bed reactor, of part or all of the hydroconverted effluent obtained at the end of the hydroconversion step, or optionally of a heavy cut from an intermediate separation step described below. The second hydroconversion stage is carried out to produce a second hydroconverted effluent. This second hydroconverted effluent advantageously contains a greater quantity of conversion products than the hydroconverted effluent from the first hydroconversion stage, 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 have a reduced Conradson carbon residue, and optionally a reduced quantity of metals, and / or sulfur, and / or nitrogen, and / or asphaltenes.

[0187] The second hydroconversion step is carried out in a manner similar to that described for the first hydroconversion step. This applies in particular to the operating conditions, the equipment used, and the hydroconversion catalyst(s) used, with the exception of the details mentioned below.

[0188] 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, 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 quantity of hydrogen introduced into the reactor remains in the range between 50 Nm3 / m3 and 5,000 Nm3 / m3 of liquid feed, preferably between 100 Nm3 / m3 and 3,000 Nm3 / m3, and even more preferably between 200 Nm3 / m3 and 2,000 Nm3 / m3. The other pressure and WH parameters are in the same ranges as those described for the first hydroconversion stage.

[0189] The operating temperature in the second hydroconversion stage may be higher than the operating temperature in the first hydroconversion stage. This may allow for a more complete conversion of the load not yet converted. The hydroconversion of liquid products from the first hydroconversion stage and the feedstock is enhanced, as are hydrotreating reactions such as hydrodesulfurization and hydrodeazotation, among others. Operating conditions are chosen to minimize the formation of solids (e.g., coke).

[0190] According to one or more embodiments, the hydroconversion process includes an intermediate separation step, between the first hydroconversion step of the feed 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 predominantly at a temperature greater than or equal to 350°C. The other fraction(s) are one or more light and intermediate fractions. The light fraction thus separated contains mainly gases (H2, H2S, NH3, and CrC4), naphtha (or gasoline, a fraction that boils at a temperature below 150°C), kerosene (a fraction that boils between 150°C and 250°C), and at least some diesel (or gas oil, a fraction that boils between 250°C and 350°C, or even 375°C). The light fraction can be sent, at least partially, to a fractionation unit where the light gases are extracted from said light fraction, for example, by passing it through an expansion vessel. The gaseous hydrogen thus recovered, which may have been sent to a purification and compression plant, can advantageously be recycled in the first hydroconversion stage, and / or in the second hydroconversion stage if implemented. The recovered gaseous hydrogen can also be used in other refinery facilities.

[0191] The optional separation step is implemented in a separation section that includes any means of separation known to a person skilled in the art. This separation section may include one or more expansion balloons 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 expansion flask, commonly called a "hot separator".

[0192] Conventionally, the hydroconverted effluent from the first or second hydroconversion stage then undergoes, at least in part, a fractionation step, which separates some or all of the hydroconverted effluent into several fractions, including at least one heavy liquid product that boils predominantly at a temperature above 350°C, preferably above 500°C, and preferably above 540°C. The heavy liquid product contains a portion that boils 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 that boils between 250°C and 375°C and a portion that boils between 375°C and 540°C (also called vacuum distillate). This fractionation step 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 include a gas / liquid separation producing at least one gas stream containing hydrogen and H2S, which can be sent to a hydrogen processing and recycling step. The fractionation section includes any separation means known to those skilled in the art, such as one or more flash balloons arranged in series, and preferably a series of at least two successive flash balloons, 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.

[0193] It is possible to recycle in the first stage of hydroconversion part of the heavy liquid product from fractionation, and / or part or all of another effluent from a further treatment (e.g. deasphalting) of the heavy liquid product from fractionation.

[0194] Step of withdrawal and replenishment of hydroconversion catalyst

[0195] The hydroconversion process according to the invention includes a step of withdrawing a spent catalyst stream from the hydroconversion reactor and introducing into the reactor a top-up comprising a recycled catalyst stream, possibly in combination with fresh catalyst.

[0196] The principle of removing spent catalyst and injecting a supplement of catalyst, in particular fresh, into the hydroconversion reactor is known, and for example described in patent FR3033797. Thus, it is known that the catalyst, when it is worn, can be partially removed, preferably from the bottom of the reactor, and replaced by introducing, either at the top or at the bottom of the reactor, a supplement of catalyst.

[0197] According to an essential aspect of the hydroconversion process according to the invention, the top-up comprises a recycled catalyst stream from the decontamination process according to the invention, optionally in combination with fresh catalyst.

[0198] The replacement of the worn catalyst is preferably carried out at regular time intervals, and preferably in bursts or almost continuously.

[0199] The withdrawal and injection of the makeup are carried out using a withdrawal and injection device advantageously adapted to continuous operation of the hydroconversion stage.

[0200] With this catalyst withdrawal / injection operation, it is therefore not necessary to stop the unit to change the spent catalyst, nor to increase the reaction temperatures along the cycle to compensate for deactivation. Furthermore, operating under constant conditions ensures consistent yields and product quality throughout the cycle.

[0201] According to one or more embodiments, the injected catalyst flow (top-up) comprises between 5% and 100% by weight of recycled catalyst (recycled hydroconversion catalyst flow), preferably between 10% and 95% by weight, preferably between 10% and 80%, relative to the total mass of the top-up.

[0202] 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 top-up consisting exclusively of fresh catalyst, which makes it possible to reduce the operating costs of the process. Examples

[0203] The examples below are intended to show certain performance characteristics of a decontamination process according to the invention of a spent catalyst. Example 1 (not in accordance with the invention)

[0204] We start from a spent catalyst called NiMo, containing molybdenum, nickel and nickel and vanadium contaminants deposited on an alumina support used in a hydroconversion process.

[0205] The fresh starting catalyst has a nickel content, expressed as NiO by weight, of 4% by weight and a molybdenum content, expressed as MoO3 by weight, of 10% by weight, the percentages being expressed in relation to the total mass of the catalyst.

[0206] The used, unregenerated catalyst contains 4.9% by weight of deposited nickel (contamination nickel) and 25.3% by weight of deposited vanadium (contamination vanadium), expressed as an element (Ni and V respectively) relative to the weight of the fresh catalyst.

[0207] A step for extracting nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (called the source catalyst) and 100 g of extraction solution are introduced into a flask. The solution The extraction sample is an aqueous solution containing 150 g / L of sulfuric acid. The mixture is stirred at room temperature at 200 rpm using a magnetic stir bar for 6 hours. The mixture is then filtered through sintered glass with a porosity of 5 to recover a polymetallic solution and a solid residue. 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 molybdenum, nickel, and vanadium are therefore 7.3%, 68.6%, and 44.6%, respectively. The mass ratio of vanadium to molybdenum is 23, and the mass ratio of nickel to molybdenum is 12. Example 2 (not in accordance with the invention)

[0208] We start from the same used catalyst as that used in example 1 containing 4.9% by weight of deposited nickel and 25.3% by weight of deposited vanadium, expressed in relation to the weight of the fresh catalyst.

[0209] A step for extracting nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (referred to as the source catalyst) and 100 g of ethanol are introduced into a flask. The mixture is stirred at room temperature at 200 rpm using a magnetic stir bar for 6 hours. The mixture is then filtered through sintered glass with a porosity of 5 to recover a polymetallic solution on the one hand and a solid residue on the other. Analysis of the solution shows that it contains 0.125 g / L of molybdenum, 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 mass ratio V / Mo is 5, and the mass ratio Ni / Mo is 2. Example 3 (according to the invention)

[0210] We start from 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 in relation to the weight of the fresh catalyst.

[0211] A step for extracting nickel and vanadium contaminants from this spent catalyst is carried out on a laboratory scale: 40 g of this spent catalyst (referred to as the 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 using a magnetic stir bar for 6 hours. The mixture is then filtered through sintered glass with a porosity of 5 to recover a polymetallic solution on the one hand and a solid residue on the other. Analysis of the solution shows that it contains 0.2 g / L of molybdenum, 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.

[0212] The extraction of metallic contaminants according to this example 3 allows a significantly more selective extraction than that of examples 1 and 2.

[0213] The catalyst obtained after extraction of metallic contaminants from the spent catalyst according to this example 3 exhibits a level of catalytic performance substantially equivalent to that of a fresh catalyst.

Claims

Demands

1. A process 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 process comprising: - a step of extracting at least a portion of the 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 hydroconversion or hydrotreating process of hydrocarbon feedstocks, and a liquid extract comprising at least vanadium and nickel.

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

3. A process 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 part of the coke of 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. A method according to any one of claims 2 and 3, wherein the regeneration step comprises combustion by contacting said spent catalyst or the 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. A method according to any one of the preceding claims, wherein the spent catalyst is previously subjected to at least one pre-treatment step selected from deoiling, water washing, and drying.

6. A process according to claim 5, wherein the spent catalyst is first subjected to: - a deoiling step by contacting said spent catalyst with a stream of inert gas at a temperature between 300°C and 400°C, or by contact with a hydrocarbon deoiling solvent, preferably chosen from the list consisting of a gasoline, a diesel, and an aromatic compound, preferably toluene, - a drying step of said spent deoiled catalyst 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, - an optional step of washing said dried deoiled catalyst with water.

7. A process according to any one of the preceding claims, wherein 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 selected from deoiling, water washing, and drying, preferably water washing 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 process 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. A process according to claim 9, wherein the concentration of sulfuric acid in the extraction solution is between 1 g / L and 300 g / L, and the concentration of alcohol in the extraction solution is between 100 g / L and 1000 g / L.

11. A process according to any one of the preceding claims, wherein 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. A process according to any one of the preceding claims, wherein the spent catalyst is derived from a fresh hydroconversion catalyst comprising: - at least one Group VIII metal, preferably selected from nickel and cobalt, preferably nickel, in combination with at least one Group VIB metal, preferably selected from molybdenum and tungsten, preferably molybdenum; - a porous oxide support(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 feed containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in a bubbling bed in the presence of hydrogen and at least one hydroconversion catalyst; and - a step of withdrawing said hydroconversion reactor of a stream of said spent hydroconversion catalyst and of 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 booster 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 booster.

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 mixture: crude oil, synthetic crude oil, coal tar, bitumen from oil sands, heavy oil from oil shale, atmospheric residue or vacuum residue from the atmospheric or vacuum distillation of crude oil, atmospheric residue or vacuum residue from the atmospheric or vacuum distillation of effluent from a thermal conversion unit or hydrotreating or hydrocracking or hydroconversion unit or a direct coal liquefaction unit, a vacuum distillate obtained directly from crude oil or from a cut from a fluidized bed catalytic cracking unit or 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, deasphalted oil or asphalt from a deasphalting unit, and preferably a vacuum residue from the vacuum distillation of crude oil.