METHOD FOR REGENERATION AND SORTING OF A USED HYDROCONVERSION CATALYST FOR HYDROCONVERSION RECYCLING

Abstract

The present invention relates to a process and installation for the treatment of a spent hydroconversion catalyst, comprising a regeneration step of the spent catalyst including the combustion of coke of said catalyst to form a regenerated catalyst, and a flotation sorting step of said regenerated catalyst including contacting said regenerated catalyst with a sorting solvent having a density chosen to separate at least a heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst, the light fraction being suitable for recycling to a hydroconversion step in at least one hydroconversion reactor operating in a bubbling bed in the presence of a hydroconversion catalyst and hydrogen.The invention also relates to a hydroconversion process for a hydrocarbon feed containing metals, incorporating the process for treating the spent catalyst and recycling the light fraction of regenerated catalyst obtained to form part of a catalyst boost in the hydroconversion reactor. Figure 1 to be published.

Description

Title of the invention: METHOD FOR REGENERATION AND SORTING OF A USED HYDROCONVERSION CATALYST FOR RECYCLING IN HYDROCONVERSION Technical field

[0001] The present invention relates to the field of hydroconversion catalysts, in particular the sorting of a spent hydroconversion catalyst for the reuse of a portion of the spent catalyst in a hydroconversion process. In particular, the present invention relates to a treatment method comprising thermal regeneration (combustion) and sorting by flotation of spent hydroconversion catalyst, with a view to its reuse in hydroconversion. Prior art

[0002] In the field of petroleum refining, the conversion of heavy hydrocarbon feedstocks, such as crude oils or heavy hydrocarbon fractions from the distillation of a crude oil, also called petroleum residues, can be carried out in hydroconversion processes using three-phase reactors (liquid, vapor and solid catalyst) operating in an ebullated bed. These hydroconversion processes are mainly aimed at converting the heavy feedstock into lighter fractions, which can be used as fuels, for example to produce gasolines or diesel fuels, or raw materials for petrochemicals.

[0003] An example of a heavy feedstock hydroconversion process using such bubbling bed hydroconversion reactors is the H-Oil® process, licensed by Axens, described for example in patents US4521295, US4495060, US4457831, or US4354852. Such a hydroconversion process typically uses one or more bubbling bed reactors in series and / or in parallel, under conditions of high pressure (for example 10-20 MPa) and high temperature (for example 410-440°C). The bubbling bed reactor contains a solid catalyst, conventionally a catalyst comprising a porous support, also called a supported catalyst, which is maintained in the reactor in the form of a fluidized bed by means of internal liquid recirculation.We thus speak of a fluidized or bubbling bed for this catalyst bed, the catalyst being in fact in a dispersed and / or expanded form, the dispersion or expansion being caused by the circulation, preferably from bottom to top, of the liquid hydrocarbon charge and the hydrogen or the gas containing the hydrogen.

[0004] An ebullated bed hydroconversion process such as the H-OIL® process is particularly well suited to heavy feedstocks containing high levels of impurities, which are difficult to treat in other reactors such as fixed bed reactors for example, and are thus capable of severely converting the heavy feed containing high levels of impurities and over a long cycle time. This is accomplished by the regular replacement, typically daily, of a small portion of the catalyst inventory contained in the reactor.

[0005] The supported catalyst, for example a NiMo catalyst on an alumina support, which is a conventional hydroconversion catalyst, is partly renewed daily with fresh catalyst to compensate for the deactivation of the catalyst induced by carbon deposits (coke) and metal deposits contained in the feedstock, mainly vanadium and nickel, in the form of metal sulfides (vanadium sulfides and nickel sulfides). This addition of fresh catalyst is accompanied by the daily extraction of spent catalyst to maintain a constant catalyst volume in the reactor.

[0006] Depending on the feedstock being treated, conventional ebullated bed reactors operate with catalyst renewal rates "r" (daily replacement rate) ranging from 0.01 to 8% by weight of the total mass of catalyst contained in the reactor (based on the mass of fresh catalyst). When the hydroconversion process contains several reactors in series, the catalyst renewal rates may be different in the different reactors.

[0007] As is known, and for example described in patent FR3033797, the spent catalyst can be withdrawn at the lower part of the reactor, and fresh catalyst can be introduced either at the upper part or at the lower part of the reactor. This replacement of spent catalyst is preferably carried out at regular time intervals, and preferably in bursts or in a quasi-continuous manner. These withdrawals / replacements are carried out using devices which advantageously make continuous operation of the hydroconversion step possible. For example, inlet and outlet tube openings in the expanded catalyst zone can be used to introduce / withdraw fresh and spent supported catalyst respectively.

[0008] Furthermore, it is known, as also mentioned in patent FR3033797 or patent EP3728518, to regenerate, or even rejuvenate and then regenerate the withdrawn spent catalyst, with a view to recycling it in the hydroconversion reactor. Regeneration makes it possible, generally by combustion, to eliminate the carbon and sulfur that the withdrawn spent catalyst contains. During rejuvenation, the majority of the metals deposited from the withdrawn spent catalyst is eliminated. The regenerated and / or rejuvenated catalyst can then constitute all or part, with fresh catalyst, of the daily catalyst top-up carried out in the hydroconversion reactor.

[0009] Patent US4621069 describes for example a regeneration of a catalyst hydroconversion of a hydroconversion process such as the H-OIL® process, in which the deactivated catalyst is continuously regenerated ex-situ by the combustion of coke. The simple regeneration step with reuse of the regenerated catalyst makes it possible to reduce the consumption of fresh catalyst. However, the gain is limited by the presence of catalyst fractions that are highly deactivated by metal deposits not removed during regeneration.

[0010] The extraction of spent catalyst is generally not selective, and particles of different ages including very young catalyst, and therefore still very active, are extracted. When we look at the age distribution of the population of spent catalysts that have been withdrawn from an H-OIL® process, we typically find that a significant fraction of catalyst is very young: typically 30% to 35% by mass of catalyst (relative to the total mass of catalyst contained in the reactor, also called the catalyst "inventory") has an age of less than 15 days, for a renewal rate "r" of the order of 2.1 to 2.7%, which is a classic example of a daily catalyst replacement rate.

[0011] Although hydroconversion reactors configured to allow selective extraction of spent catalyst are known, these are generally complex and expensive. For example, patent applications FR3075069 and FR3075070 describe reactors with horizontal or vertical compartments constituting hydroconversion zones of different catalytic activity, the compartments preventing the transfer of catalyst from one hydroconversion zone to another, but being able to allow the transfer of fluids. The reactors are equipped with a device for withdrawing and injecting catalyst from one zone to another, so as to transfer a catalyst supplement from one compartment to another having a lower catalytic activity. In these reactors, only the equivalent of catalyst supplement is extracted from the reactor from the compartment having the lowest average catalytic activity.These compartmentalized reactors thus make it possible to selectively extract the catalyst from the hydroconversion reactor, depending on its age, so as to only withdraw the "oldest" fraction, i.e. having the lowest average catalytic activity, and replace it with fresh and / or regenerated and / or rejuvenated catalyst. This type of reactor makes it possible to optimize catalyst renewal by limiting the loss of the most active catalyst, and thus increase reactor performance and / or reduce the catalyst replacement rate.

[0012] Today, in the case of non-selective extraction of the hydroconversion catalyst from the hydroconversion reactor, no sorting of the withdrawn spent catalyst is carried out industrially, with a view to its recycling in the hydroconversion process. In general, all of the withdrawn spent catalyst is sent to a metal recovery line aimed at recovering all the metals from the catalyst, without reuse of the catalyst, even if theoretically regeneration and / or rejuvenation are possible.

[0013] Generally speaking, methods exist for selecting the catalyst grains least deactivated by metals: these methods are based, for example, on centrifugation, elutriation, magnetism, surface chemical analysis, etc.

[0014] Patent US4720473 describes, for example, a method for treating a spent hydrotreatment catalyst supported with uniform geometry, comprising separation of the particles according to their length and density using a rotating screen and an elutriation system such as a gas-phase fluidized bed for particle density segregation. The lightest separated fraction (weakly contaminated by metals) is then sent to a regeneration zone to remove carbon deposits, so that it can then be sent to a hydrotreatment zone. However, the gas-phase fluidization on which the sorting is partially based during this process is a strong constraint because it is aggressive for the mechanical strength of the catalyst grains. Indeed, elutriation by gas-phase fluidization produces yield losses due to grain attrition.

[0015] Another example of catalyst sorting is given in application WO17108378, which describes the segregation of catalyst grains by a grain-by-grain analysis method, based on imaging or microscopy techniques allowing analysis at the millimeter scale of catalyst grains, without or with density separation. This method requires grain-by-grain analysis, which can be complex and ultimately unsuitable for large tonnages, as is the case for the majority of refining processes involving catalyst replacement in ebullated bed, fluidized bed or moving bed reactors. Objectives and Summary of the Invention

[0016] The present invention aims to overcome at least in part the problems of the prior art described above, and aims in particular to provide a method for treating a spent hydroconversion catalyst making it possible to recover a fraction of "young" spent catalyst, i.e. a fraction of the spent catalyst which has spent little time in the hydroconversion reactor and which still has interesting catalytic activity, with a view to recycling said fraction in an ebullated bed reactor during a hydroconversion step of a heavy feedstock.

[0017] One objective is to provide such a method for treating a spent hydroconversion catalyst, comprising sorting which is suitable for the industrial treatment of large quantities of spent catalyst.

[0018] Another objective is to provide such a method for treating a spent hydroconversion catalyst, comprising sorting which minimizes the physical deterioration of the catalyst grains, and thus maximizes the mass yield of the ca- fraction. reusable used talyst.

[0019] The present invention generally aims to reduce the overall consumption of fresh catalyst during a hydroconversion process, and / or to increase the catalytic activity during hydroconversion with an iso-addition of fresh catalyst in the case of recycling of spent catalyst during hydroconversion.

[0020] Thus, to achieve at least one of the above-mentioned objectives, among others, the present invention proposes, according to a first aspect, a method for treating a used hydroconversion catalyst, comprising: - a step of regenerating the spent hydroconversion catalyst comprising removing coke from the spent hydroconversion catalyst, preferably by combustion, to form a regenerated catalyst, - a step of sorting by flotation of said regenerated catalyst resulting from the regeneration step comprising bringing said regenerated catalyst into contact with a sorting solvent having a density chosen so as to separate at least one heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst, the light fraction being capable of being recycled to a hydroconversion step in at least one hydroconversion reactor operating in an ebullated bed in the presence of a hydroconversion catalyst and hydrogen.

[0021] According to one or more implementations, the regeneration step is carried out by combustion by bringing said spent hydroconversion catalyst into contact with a regeneration gas stream comprising oxygen at a temperature between 350°C and 600°C, preferably between 400°C and 550°C, preferably between 450°C and 550°C.

[0022] According to one or more implementations, the treatment method comprises, prior to the regeneration step: - washing the used hydroconversion catalyst using a washing solvent, preferably the washing solvent being a hydrocarbon solvent, advantageously chosen from the list consisting of a gasoline, a diesel, and an aromatic compound, preferably toluene; and - drying the washed used hydroconversion catalyst by contacting it with a drying gas and / or by heating, preferably in contact with air, and preferably at a temperature between 50°C and 200°C.

[0023] According to one or more implementations, the composition of the sorting solvent is modified during the flotation sorting step so that the density of the sorting solvent varies over time to separate one or more additional fractions of regenerated catalyst.

[0024] According to one or more implementations, the density of the sorting solvent is fixed during the flotation sorting step so as to separate only two fractions of ca regenerated catalyst consisting of the heavy fraction of regenerated catalyst and the light fraction of regenerated catalyst.

[0025] According to one or more implementations, the sorting solvent in the flotation sorting step is chosen so that its density is greater than the structural density of a fresh hydroconversion catalyst from which said spent hydroconversion catalyst is derived.

[0026] According to one or more implementations, the density of the solvent is chosen so that the light fraction of regenerated spent catalyst comprises a level of metals deposited during the hydroconversion step less than or equal to 15% by weight relative to the weight of the fresh hydroconversion catalyst.

[0027] According to one or more implementations, the density of the sorting solvent in the flotation sorting step is between 2.1 g / cm3 and 4.5 g / cm3, preferably between 2.6 and 3.5 g / cm3, preferably is between 2.8 g / cm3 and 3.4 g / cm3.

[0028] According to one or more implementations, the sorting solvent in the flotation sorting step comprises diiodomethane, or a mixture of diiodomethane and chloroform, or an aqueous Cleirici solution comprising a mixture of thallium formate and thallium malonate in equal parts.

[0029] According to one or more implementations, the regeneration step is carried out in a regeneration unit fluidically connected to a sorting unit in which the flotation sorting step is carried out, and the regenerated catalyst is transferred from said regeneration unit to the sorting unit, preferably by pneumatic transport or by transport in the form of a suspension comprising a transport liquid, preferably the transport liquid being the sorting solvent used in the flotation sorting step.

[0030] According to one or more implementations, the spent hydroconversion catalyst is derived from a fresh hydroconversion catalyst comprising: - at least one metal from Group VIII of the periodic table of elements, preferably chosen from nickel and cobalt, preferably nickel, preferably in combination with at least one metal from Group VIB, preferably chosen from molybdenum and tungsten, preferably molybdenum; - a porous support of said metal(s), preferably said support comprising silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia or combinations thereof, and preferably alumina.

[0031] According to a second aspect, the invention proposes treatment of a used hydroconversion catalyst comprising: - a unit for regenerating said spent hydroconversion catalyst comprising a reactor for combustion of coke from the spent hydroconversion catalyst to form a regenerated catalyst; - a connected regenerated catalyst flotation sorting unit, preferably of fluidically, to said catalyst regeneration unit, said flotation sorting unit comprising a tank for bringing the regenerated catalyst into contact with a sorting solvent and means for separating a heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst.

[0032] According to a third aspect, the invention proposes a hydroconversion process comprising: - a step of hydroconversion of a hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and a hydroconversion catalyst and; - a step of withdrawing from said hydroconversion reactor a flow of said spent hydroconversion catalyst and introducing into said hydroconversion reactor a make-up comprising a flow of fresh hydroconversion catalyst and a flow of recycled hydroconversion catalyst; - a step of treating said flow of used hydroconversion catalyst withdrawn by a treatment method according to the invention, producing a light fraction of regenerated hydroconversion catalyst forming the flow of recycled hydroconversion catalyst.

[0033] According to one or more implementations, the make-up comprises between 5% and 35% by weight of the recycled hydroconversion catalyst stream, preferably between 10% and 30% by weight.

[0034] According to one or more implementations, 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 be constituted by, one of the following feedstocks, alone or in a mixture: a crude oil, a synthetic crude oil, a coal tar, a bituminous sands bitumen, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion or hydrotreatment or hydrocracking or hydroconversion unit or from a direct coal liquefaction unit,a vacuum distillate obtained directly from a crude oil or from a cut from a fluidized bed catalytic cracking unit or from a hydrocracking unit or from a hydroconversion unit or from a coking unit or from a visbreaking unit, a vacuum distillate from the direct liquefaction of coal, aromatic cuts extracted from a lubricant production unit, a deasphalted oil or an asphalt from a deasphalting unit, and preferably a vacuum residue from the vacuum distillation of a crude oil.

[0035] Other objects and advantages of the invention will appear on reading the description which follows examples of particular embodiments of the invention, given as non-limiting examples, the description being made with reference to the appended figures described below. List of figures

[0036] [Fig.l]

[0037] [Fig.l] illustrates the invention and represents a schematic diagram of the process for treating a hydroconversion catalyst and of the hydroconversion process incorporating such treatment.

[0038] [Fig.2]

[0039] [Fig.2] illustrates an experimental device implemented for laboratory tests of sorting by catalyst flotation.

[0040] [Fig.3]

[0041] [Fig. 3] is a graph showing the mass recovery results obtained during laboratory tests of catalyst flotation sorting. Description of the embodiments

[0042] In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the methods. However, it will be apparent to those skilled in the art that the methods may be practiced without necessarily all of these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0043] 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

[0044] It is specified that, throughout this description, the expression "between ... and ..." must be understood as including the limits cited, unless otherwise specified.

[0045] In this description, the term "comprise" is synonymous with "comprise", "include" and "contain", and is inclusive or open and does not exclude other elements that are not mentioned. It is understood that the term "comprise" includes the exclusive and closed term "consist".

[0046] Furthermore, when used in the present description, the terms "essentially" or "substantially" or "approximately" in relation to a reference value correspond to an approximation of ± 10%, preferably ± 5%, very preferably ± 2%, or even more preferably ± 1% of this reference value, which may be a temperature, a pressure, a distance, a speed, a flow rate, a content of compound(s), etc.

[0047] In the present description, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​may be combined with a more preferred range of temperature values.

[0048] In the present description, the term "hydroconversion catalyst" means a porous supported catalyst used in an ebullated bed hydroconversion process of a hydrocarbon feedstock. In the remainder of the description, the term "catalyst" refers to such a hydroconversion catalyst, unless otherwise specified. Such catalysts typically comprise (i) a catalyst support having a large surface area and numerous interconnected channels or pores and (ii) an active phase in the form of fine particles of an active catalyst such as sulfides of cobalt, nickel, tungsten, molybdenum, or mixed sulfides of these elements (e.g. NiMo, CoMo, etc.), dispersed in the pores. Supported catalysts are commonly produced in the form of cylindrical extrudates ("pellets" in English) or spherical solids, although other shapes are possible. Such a hydroconversion catalyst is detailed later in the description.

[0049] In this specification, the term "hydroconversion" refers to a process whose primary purpose is to reduce the boiling point range of a hydrocarbon feedstock typically comprising at least 50% by weight of a heavy hydrocarbon fraction having a boiling point of at least 300°C, and wherein a substantial portion of the feedstock is converted to products having lower boiling point ranges than the original feedstock. Hydroconversion generally involves the fragmentation of larger hydrocarbon molecules into smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen to carbon ratio. The reactions carried out during hydroconversion reduce the size of hydrocarbon molecules, primarily by cleavage of carbon-carbon bonds, in the presence of hydrogen to saturate the cleaved bonds and aromatic rings.The mechanism by which hydroconversion occurs typically involves the formation of hydrocarbon free radicals during fragmentation, primarily by thermal cracking, followed by capping of the free radical termini or fragments with hydrogen in the presence of active catalyst sites. Of course, during a hydroconversion process, other reactions typically associated with hydrotreating may occur, such as, among others, the removal of sulfur or nitrogen from the feedstock, or the saturation of olefins, and as more broadly defined below.

[0050] The term "hydrotreatment", commonly called "HDT", refers to a gentler operation than hydroconversion, and whose main purpose is to eliminate impurities such as sulfur, nitrogen, oxygen, halides, and trace metals from the feedstock, and to saturate olefins and / or stabilize hydrocarbon free radicals by reacting them with hydrogen rather than allowing them to react with themselves. The primary purpose is not to change the boiling point range of the feedstock. Thus, hydrotreating includes, among other things, hydrodesulfurization reactions (commonly referred to as "HDS"), hydrodenitrogenation reactions (commonly referred to as "HDN"), and hydrodemetalation reactions (commonly referred to as "HDM"), along with hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydrodeasphalting, and Conradson carbon reduction.Hydroprocessing is most commonly carried out using a fixed bed reactor, although other reactors can also be used for hydroprocessing, for example an ebullated bed hydroprocessing reactor.

[0051] For the purposes of the present invention, the term "flotation sorting" or "separation by flotation" ("separation by flotation" in English terminology) means a technique for separating mixtures of solid particles based on the difference in their density in a liquid medium, based on the principle of Archimedes' thrust. The term flotation is sometimes used for this technique. However, flotation is a separation technique based on differences in density and / or hydrophobicity of the elements to be separated, and may thus include surface properties (hydrophobicity) which are not used in the flotation sorting implemented in the present invention.Thus, the term "flotation" is preferred in the present description to refer to the sorting mechanism of the method according to the invention, although reference may also be made to flotation, and more specifically to a natural flotation technique where the difference in density between the suspended granular material and the liquid which contains it is naturally sufficient to allow the separation of the grains, as opposed to assisted or induced flotation techniques which may implement the blowing of air bubbles to improve the separation or even artificially modify a particle density initially higher than that of the liquid, by associating gas bubbles with them.

[0052] The term "structural density", in reference to a catalyst as a material, and also sometimes called "skeletal density" or "true density" or "absolute density", corresponds to the density of the catalyst excluding the porosity and the density of its interstitial fluids. This is the usual definition of structural density, as opposed to apparent density which takes into account all the components of the catalyst (including its porosity and interstitial fluids). The structural density of a grain can be written as follows: ps = mgrain / (Vgrain-VpOres), with ps the structural density of the grain, m grain the mass of the solid grain, Vgrain the total volume (or envelope) of the solid grain which is the volume including the open pores, and Vpores the volume of the open pores of the grain. It is determined by helium pycnometry, according to ASTM B923. Other methods may be used to determine the structural density of a catalyst, and do not limit the invention.

[0053] The standards cited in this description refer to the most recent versions on the date of filing of this application.

[0054] In the present description, the "rate of deposited metals" or "rate of metals deposited during hydroconversion" refers to an average deposition rate of metals from the feedstock onto the catalyst during the hydroconversion step, and corresponds to the total mass of metals from the feedstock deposited in / on the catalyst during hydroconversion divided by the total mass of fresh catalyst (the fresh catalyst comprising the support and the active phase). The rate of deposited metals is expressed as a mass percentage of metals relative to the total mass of fresh catalyst. When reference is made to the total mass of the fresh catalyst to express certain contents in mass % of catalyst compounds, this is the total mass of the fresh catalyst in its oxide (non-sulfurized) form. The deposited metal rate can be estimated mathematically from the metal content in the hydrocarbon feedstock, the total mass of hydrocarbon feedstock treated, the total demetallation performance of the feedstock (HDM reactions and / or deposits), the catalyst inventory (quantity) and the hydroconversion catalyst replacement rate. The metal content is preferably determined from analyses of the withdrawn spent catalyst. According to this preferred approach, a sample of withdrawn spent catalyst is taken, said sampled catalyst is washed in the laboratory using a Soxhlet extractor using a solvent such as toluene to extract the liquid products without extracting the metals, and then said washed catalyst sample is dried, typically in an atmospheric or vacuum oven, at a temperature sufficient to evaporate the solvent, for example at 120°C in the case of toluene. The washed and dried catalyst sample can then be analyzed to determine its elemental composition. Preferably, the spent, washed and dried catalyst sample is regenerated, typically in an oven, for example at a temperature of about 500°C, to remove the coke. In the laboratory, regeneration is typically carried out in an air oven, preferably with a slow temperature increase (for example with one or more temperature steps) in order to avoid the formation of hot spots. The regenerated catalyst sample is then ground before being analyzed. Elemental analyses, typically by inductively coupled plasma spectrometry (ICP), or by X-ray fluorescence spectrometry, more commonly known as X-ray fluorescence (FX), can quantify the content of different elements in the catalyst, including aluminum and molybdenum for the most typical hydroconversion catalysts, as well as metals deposited during hydroconversion, such as vanadium and nickel for the most typical petroleum feedstocks treated in a hydroconversion process, and any other element. The deposited metal content (average deposition rate of metals from the feedstock onto the catalyst during the hydroconversion step) for the analyzed catalyst sample can be estimated by taking into account the known composition of the fresh catalyst. It should be noted that in the sample of withdrawn spent catalyst, as in a sorted fraction of the catalyst regenerated by the treatment method according to the invention, there is an age distribution of the catalyst grains (variable residence time in the reactor depending on the grains), and therefore also a distribution in deposits of deposited metals since the quantity of metals deposited during the hydroconversion depends on the residence time of the catalyst grain in the hydroconversion reactor (the longer the residence time, the greater the metal deposits on the grain). For the purposes of the present invention, the rate of deposited metals of the withdrawn spent catalyst refers to the average mass of deposited metals relative to the total mass of fresh catalyst estimated in the analyzed catalyst sample.

[0055] In the present 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 of columns 8, 9 and 10 according to the new IUP AC classification.

[0056] For a better understanding of the invention, reference is made below to numerical references appearing in [Fig.l] to designate different elements of the methods, without this constituting a limitation to the particular embodiments described below.

[0057] The applicant has demonstrated that, surprisingly, it is possible to meet the objectives sought by treating the spent catalyst according to a precise sequence of steps: firstly, a step of regeneration of the spent catalyst which aims to remove the coke deposits from the spent catalyst, typically a thermal regeneration comprising combustion of the coke, or any other method of removing the coke, followed by a flotation sorting step which will make it possible to separate the catalyst grains according to their content of metals deposited during the hydroconversion, the latter being a strictly increasing function of the age of the catalyst, and provide a light fraction of regenerated catalyst having a low level of deposited metals, and therefore still having satisfactory catalytic activity, said fraction then being able to be recycled to hydroconversion.

[0058] By age of the hydroconversion catalyst is meant the residence time of the catalyst in the hydroconversion reactor

[0059] Catalyst regeneration, as already mentioned above, is a known and well-mastered process in the petroleum industry for removing carbon deposits from catalysts. Flotation separation, which is based on the difference in the density of solid particles to be separated compared to the density of a liquid in which they are immersed, is also a known process that is used in other fields such as the mining industry, wastewater treatment, or the food industry.

[0060] The invention relates to the combination of the two techniques for the treatment of a used hydroconversion catalyst, in particular to a specific sequence comprising a regeneration step prior to a flotation sorting step, which makes it possible to carry out reliable and efficient sorting of the used catalyst with a view to its recycling for hydroconversion. Without this first regeneration step prior to sorting, it is not possible to carry out satisfactory separation of the catalyst by age, as explained later in the description.

[0061] [Fig. 1] is a block diagram showing the process for the ebullated bed hydroconversion of a hydrocarbon feedstock and the treatment of the spent hydroconversion catalyst according to the invention, said spent catalyst being withdrawn from at least one ebullated bed hydroconversion reactor of the hydroconversion process.

[0062] A hydrocarbon feedstock containing metals, not shown in [Fig.l], is sent to a hydroconversion step 1 in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and a porous supported hydroconversion catalyst. Into said hydroconversion reactor is introduced a make-up comprising a flow of fresh hydroconversion catalyst 11 partially compensating for a flow of spent hydroconversion catalyst 12 withdrawn from the reactor.

[0063] The spent catalyst stream 12, which contains coke deposits and metal deposits, is sent to a catalyst regeneration step 2 for coke removal, preferably thermal regeneration by combustion, producing a regenerated spent catalyst stream 13 free of coke or having a low coke content, preferably the regenerated spent catalyst stream having less than 5% by weight of carbon relative to the total weight of fresh catalyst, preferably less than 1% by weight of carbon. Any other suitable coke removal method, i.e. one that does not damage the catalyst, may be used. The regenerated spent catalyst stream 13 still containing deposited metals is then sent to a flotation sorting step 3. In this step, the ca grains catalyst will be separated according to their structural density which is directly linked to the metal content and therefore to the age of the catalyst grain: the catalyst grain in fact accumulates metals, initially contained in the charge, throughout its life in the hydroconversion reactor. At the end of the flotation sorting step 3, at least one fraction of catalyst rich in metals is obtained, here called the heavy fraction of regenerated catalyst 14, which contains the so-called “old” catalyst grains, and a fraction of catalyst poor in metals, here called the light fraction of regenerated catalyst 15, which contains the so-called “young” and still active catalyst grains.

[0064] The light fraction of regenerated catalyst 15 is recycled to step hydroconversion 1, to form, with the flow 11 of fresh catalyst, the top-up which compensates for the withdrawal of used catalyst 12.

[0065] This recycling thus makes it possible to reduce the supply of fresh catalyst compared to a conventional scheme without sorting and recycling part of the used catalyst withdrawn and regenerated. With the same amount of fresh catalyst as in a conventional scheme, recycling the light fraction of regenerated catalyst makes it possible to increase catalytic activity during hydroconversion.

[0066] Process for treating a spent hydroconversion catalyst

[0067] According to a first aspect, the present invention thus relates to a method for treating a used hydroconversion catalyst, comprising: - a regeneration step 2 of the spent hydroconversion catalyst 12 comprising removal of the coke from said spent hydroconversion catalyst 12, preferably by combustion, to form a regenerated catalyst 13, - a flotation sorting step 3 of said regenerated catalyst 13 comprising bringing said regenerated catalyst 13 into contact with a sorting solvent having a density chosen so as to separate at least one heavy fraction of regenerated catalyst 14 and a light fraction of regenerated catalyst 15, the light fraction being capable of being recycled to a hydroconversion step 1 in at least one hydroconversion reactor operating in an ebullated bed in the presence of a hydroconversion catalyst and hydrogen. The hydroconversion catalyst

[0068] The spent hydroconversion catalyst treated by the treatment process according to the invention comes from at least one ebullated bed reactor of a hydroconversion section of a process for hydroconversion of a hydrocarbon feedstock containing metals. Such a reactor is a three-phase reactor containing hydrogen and a fluidized bed catalyst called an ebullated bed, and operating with an ascending flow of liquid and gas. The ebullated bed hydroconversion reactor is described in detail below in relation to the hydroconversion process.

[0069] An essential aspect of the operation of ebullated bed reactors is the continuous replacement of the hydroconversion catalyst. Catalyst replacement is required in all hydrocarbon feedstock conversion processes (regardless of the reactor technology employed, e.g., fixed bed, moving bed, or bubbling fluidized bed reactor), because the catalyst is deactivated primarily by deposition of metals contained in the feedstock, and by deposition of coke, under the operating conditions of hydroconversion.

[0070] The deposited metals can interact with the active sites of the catalyst, and block them, reducing the catalyst's ability to catalyze the reactions, i.e. leading to a progressive deactivation of the catalyst. The nature of the deposited metals depends on the nature of the metals present in the treated feedstock of the hydroconversion process. Coke deposits can also deactivate the active sites of the catalyst, or clog the pores and thus make the active sites less accessible to the reactants.

[0071] The ebullated bed technology, while it does in fact ultimately increase the time between two stops of the hydroconversion process thanks to the continuous aspect of catalyst renewal, compared to other technologies such as fixed bed technologies, requires the implementation of a continuous catalyst renewal system, with catalyst withdrawal and top-up every day. As the catalyst is very strongly mixed in the ebullated bed, after an initial stabilization period, a state of equilibrium is reached for the distribution of catalyst age and activity, thus allowing operation at constant operating conditions with constant performance over time.The CRR catalyst renewal rate, which is a daily replacement rate, can vary from 0.01 to 8% by weight of the total mass of catalyst contained in the reactor (mass of fresh catalyst), depending on the feedstock treated, and this rate can be different for each hydroconversion reactor if several reactors are used.

[0072] The 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 ebullated bed hydroconversion reactor, a disadvantage encountered is that the withdrawn spent catalyst consists of a mixture of very highly deactivated catalyst, moderately deactivated catalyst and almost new catalyst, so that the use of the catalyst in ebullated bed hydrotreatment reactors is not optimized.

[0073] A sorting of the particles of withdrawn spent hydroconversion catalyst according to their degree of deactivation is proposed by the present invention, with a view to recycling to the hydroconversion of a still sufficiently active fraction of the withdrawn catalyst, in addition to fresh (new) catalyst to form the daily catalyst make-up. hydroconversion.

[0074] The spent catalyst is derived from a fresh, i.e. new (never used) hydroconversion catalyst, described below.

[0075] The fresh hydroconversion catalyst may contain one or more elements from groups 4 to 12 of the periodic table of elements, deposited on a porous support. Said porous support is advantageously a support comprising, and which may be constituted by, silica, alumina, silica-alumina (amorphous), titanium dioxide, clay, boron oxide, zirconia, or combinations of these materials, preferably comprising, and which may be constituted by, silica, alumina, silica-alumina (amorphous), titanium dioxide or combinations thereof, and very preferably alumina. The alumina may advantageously be in all its forms, known to those skilled in the art. For example, the alumina is chosen from the group composed of alpha, rho, chi, kappa, eta, gamma, theta and delta aluminas, preferably chosen from gamma, theta and delta aluminas, and even more preferably is gamma alumina, for example boehmite.

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

[0077] In certain cases, it may be advantageous for the support to comprise, in addition to the refractory oxide material described above, for example alumina, at least one zeolitic material, which may in particular provide a cracking function in addition to the hydro-dehydrogenating function provided by the metals of the active phase, said zeolitic material forming, with the refractory oxide, the porous support within which the metals of the active phase are dispersed. Said zeolite material may be a zeolite chosen from zeolites of MFI, BEA and FAU structure, and preferably chosen from ZSM-5, beta or Y zeolites. With regard to the zeolites mentioned in the present description, those skilled in the art may refer to the work "Atlas of zeolite framework types", 6th revised Edition, 2007, Ch.Baerlocher, W.M.Meier, D.H.Olson to obtain the characteristics thereof.

[0078] The fresh hydroconversion catalyst may contain at least one metal from group VIII, preferably chosen from nickel and cobalt, and preferably nickel, said group VIII element preferably being used in association with at least one metal from group VIB, preferably chosen from molybdenum and tungsten, and preferably the metal from group VIB is molybdenum.

[0079] Advantageously, the fresh hydroconversion catalyst comprises an alumina support and at least one metal from group VIII chosen from nickel and cobalt, preferably nickel, and at least one metal from group VIB chosen from molybdenum and tungsten, preferably molybdenum. Preferably, the fresh hydroconversion catalyst comprises nickel as a group VIII element and the molybdenum as a group VIB element.

[0080] The fresh hydroconversion catalyst can therefore comprise: - at least one metal from Group VIII, preferably chosen from nickel and cobalt, and preferably nickel, preferably in combination with at least one metal from Group VIB, preferably chosen from molybdenum and tungsten, and preferably molybdenum; - a porous support, serving as a support for said metal(s), preferably the porous support comprising, and possibly consisting of, silica, alumina, silica-alumina, titanium dioxide, clay, boron oxide, zirconia, or combinations thereof, and preferably silica, alumina, silica-alumina, titanium dioxide or combinations thereof, and even more preferably alumina.

[0081] The content of group VIII metal, in particular nickel, is advantageously between 0.5% and 10% expressed by weight of metal oxide (in particular NiO), and preferably between 1% and 6% by weight, and the content of group VIB metal, in particular molybdenum, is advantageously between 0% and 30% expressed by weight of metal oxide (in particular molybdenum trioxide MoO3), preferably between 1% and 30%, and preferably between 4% and 20% by weight. The metal contents are expressed as a percentage by weight of metal oxide relative to the weight of the fresh hydroconversion catalyst.

[0082] The fresh hydroconversion catalyst may also comprise at least one doping element chosen from phosphorus, boron, silicon, preferably phosphorus.

[0083] The fresh hydroconversion catalyst may also further comprise at least one organic compound containing oxygen and / or nitrogen and / or sulfur before sulfurization. Such additives are known to those skilled in the art. Generally, the organic compound is chosen from a compound comprising one or more chemical functions chosen from a carboxylic function, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide or compounds including a furan cycle or sugars.

[0084] This supported fresh hydroconversion catalyst is advantageously used in the form of extrudates or beads. The beads have, for example, a diameter of between 0.4 mm and 4.0 mm. The extrudates have, for example, a cylindrical shape with a diameter of between 0.5 mm and 4.0 mm and a length of 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. Porous supported fresh hydroconversion catalysts of other shapes may can also be used. The size of these different forms of porous supported catalysts can be characterized by means of the equivalent diameter. The equivalent diameter is defined as six times the ratio of the particle volume to the external surface area of ​​the particle. The porous supported catalyst, used in the form of extrudates, beads or other forms, thus has an equivalent diameter between 0.4 mm and 4.4 mm.

[0085] Advantageously, the fresh hydroconversion catalyst undergoes a sulfurization step before its use, consisting of activating the catalyst by transforming, at least in part, the oxide phase into a sulfide-reducing medium. This sulfurization 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] A conventional sulfurization method well known to those skilled in the art consists of heating the catalyst under a flow of a mixture of hydrogen and hydrogen sulfide or under a flow of a mixture of hydrogen and hydrocarbons containing sulfur molecules at a temperature between 150°C and 800°C, preferably between 250°C and 600°C. The sulfurization treatment can be carried out ex situ (before the introduction of the fresh catalyst into the hydroconversion reactor) or in situ using an organosulfur H2S precursor injected with the heavy hydrocarbon feedstock to be treated. It is preferably carried out in situ when an ebullated bed reactor is used. The H2S can also come, for example, from the H2S contained in hydrogen recycled to the hydroconversion reactor or from the thermal decomposition of organosulfur molecules present in the feedstock or previously introduced into the feedstock (e.g. injection of dimethyl disulfide, sulfur compounds of the mercaptan or sulfide type, sulfur-containing gasoline, sulfur-containing diesel, sulfur-containing vacuum distillate, sulfur-containing residue).

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

[0088] The spent catalyst, which has been withdrawn from the ebullated bed hydroconversion reactor, and which is sent to the regeneration stage, comprises deposits of coke and metals initially contained in the hydrocarbon feedstock sent to the hydroconversion. The amount of metals and coke deposited during hydroconversion varies from one catalyst grain to another, and is a function of the residence time of the catalyst grain in the hydroconversion reactor. It also depends, as does the nature of the metals, on the nature of the hydrocarbon feedstock.

[0089] Typically, the spent hydroconversion catalyst comprises nickel and / or vanadium initially contained in the hydrocarbon feedstock sent to the hydroconversion, and deposited on / in the catalyst at the hydroconversion stage.

[0090] The rate of deposited metals of the spent hydroconversion catalyst can be understood between 5% and 150% by weight relative to the weight of fresh hydroconversion catalyst.

[0091] The carbon content (bound to coke) of the spent hydroconversion catalyst may be between 5% and 90% by weight of the fresh hydroconversion catalyst, preferably between 5% and 50% by weight.

[0092] Hydroconversion catalyst regeneration step

[0093] The regeneration step 2 of the spent catalyst 12 is a catalyst regeneration step aimed at removing the coke from the spent catalyst. This is advantageously a thermal regeneration comprising the combustion of the coke from the spent 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.

[0094] Thermal regeneration of a catalyst by combustion is known to those skilled in the art. This step consists of carrying out controlled combustion of the coke deposits of the catalyst. It makes it possible to restore part of the active sites of the catalyst by eliminating the coke which deactivates the sites, or limits or blocks the access of the reactants by clogging the pores. During the regeneration step, other compounds may undergo oxidation, with sulfur or nitrogen compounds possibly forming SOx and NOx.

[0095] The regeneration step is carried out on the spent catalyst stream 12, which may have been washed or have undergone decantation of the oil which soaks it, then dried.

[0096] Thus, the treatment method may comprise, prior to the regeneration step: - washing the spent catalyst stream 12 using a washing solvent, preferably said washing solvent being a hydrocarbon solvent, preferably chosen from the list consisting of gasoline, diesel, and an aromatic compound, preferably toluene; and - drying said washed used catalyst by contacting with a drying gas and / or by heating, preferably at a temperature between 50°C and 200°C. The drying gas is preferably an inert gas such as nitrogen.

[0097] The drying step can be carried out by any means known to those skilled in the art, for example in an enclosure operating in a fluidized bed, or in a fixed bed, or in an oven comprising a belt.

[0098] According to one or more embodiments, the regeneration comprises the combustion of the spent catalyst stream 12 by bringing said stream 12 into contact with a stream of regeneration gas comprising oxygen, at a temperature between 350°C and 600°C, preferably between 400°C and 550°C, more preferably between 450°C and 550°C.

[0099] The regeneration gas stream preferably comprises air.

[0100] Regeneration by combustion begins with the introduction of the regeneration gas flow, for example air, advantageously mixed with an inert gas such as nitrogen, into the combustion reactor of the regeneration unit. This flow 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.

[0101] The combustion regeneration step can be implemented by any type of equipment known to those skilled in the art, for example comprising one or more combustion reactors which can be furnaces, including rotary furnaces and furnaces equipped with moving belts, horizontal bed reactors equipped with a propeller for the advancement and homogenization of the catalyst, vibro-fluidization devices, fixed bed reactors, moving bed reactors, fluidized bed reactors, fluidized bed reactors having the advantage of better temperature distribution in order to avoid hot spots. Typical stay times are 1 hour to 5 hours.

[0102] During combustion regeneration, the flow of regeneration gas comprising oxygen coming into contact with the spent catalyst causes the oxidation of the coke deposits. The heat released during the oxidation reaction contributes to maintaining the temperature of the combustion reactor in 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.

[0103] Once regeneration is complete, the regeneration gas flow is interrupted, and a regenerated catalyst flow 13 is ready to be sent to the flotation sorting step 3.

[0104] The regeneration step can be carried out in a delocalized manner relative to the hydroconversion unit of the hydroconversion process, which can be referred to as ex-situ regeneration, or in line with the hydroconversion process, i.e. in a non-delocalized manner relative to the hydroconversion unit, which can also be referred to as in-situ regeneration.

[0105] Preferably, the regeneration step is carried out discontinuously (also called “batch”) and at a frequency defined according to the desired catalyst management.

[0106] A discontinuous (batch) implementation of the regeneration step, whether in-situ or ex-situ, may require the use of buffer tanks for the withdrawn spent catalyst and / or the light fraction of regenerated catalyst capable of being recycled to the hydroconversion step.

[0107] Advantageously, the regenerated catalyst resulting from the regeneration step comprises less than 5% by weight of coke, preferably less than 1% by weight of coke, relative to the total weight of said regenerated catalyst.

[0108] The duration, as well as the frequency at which the regeneration step is carried out if it is implemented in line with the hydroconversion process, may vary depending on the specific characteristics of the hydroconversion catalyst, as well as the composition of the treated hydrocarbon feedstock. They may be adjusted so that the regenerated catalyst from the regeneration step comprises less than 5% by weight of coke, preferably less than 1% by weight of coke, relative to the total weight of said regenerated catalyst.

[0109] The regeneration step 2 of the spent catalyst 12 before the flotation sorting step 3 is essential in the treatment method according to the invention. Indeed, without the prior regeneration of the spent catalyst, it would not be possible to achieve a satisfactory separation of the spent catalyst according to its age by flotation sorting. Against all expectations, the applicant has demonstrated that flotation sorting implemented as detailed below, carried out on a non-regenerated spent catalyst stream, did not make it possible to obtain an efficient sorting of the catalyst, i.e. reflecting the age of the catalyst (residence time in the hydroconversion reactor), and therefore did not make it possible to provide a satisfactory fraction of catalyst, in terms of activity and quantity, with a view to its recycling to hydroconversion. Advantageously, regeneration step 2 makes it possible to eliminate a maximum of the coke deposited during the hydroconversion step. The coke, which is deposited very quickly during the first days of the catalyst's life in the hydroconversion reactor, has a low structural density of around 1 g / cm3. While the fresh catalyst has a structural density generally between 2.0 g / cm3 and 3.5 g / cm3, for example 3.0 g / cm3, the deposition of coke during the hydroconversion step therefore tends to lower the structural density of the catalyst remaining in the hydroconversion reactor, while the deposition on the catalyst of metals initially included in the feedstock, which generally have a density greater than the structural density of the fresh catalyst (eg: NiS: 5.6 g / cm3, NiS2: 5.87 g / cm3, V2S3: 4.7 g / cm3), tends to increase the structural density of the catalyst during hydroconversion, the two types of deposits then having an antagonistic influence on the structural density of the spent catalyst.Thus, a spent catalyst grain may have a lower structural density than a fresh catalyst grain because of the coke deposit which can be significant, typically 5 to 50% by weight of the fresh catalyst, or even beyond and up to 90% by weight of the fresh catalyst.

[0110] The elimination of coke during regeneration step 2 makes it possible to overcome as much as possible the effect of coke on the structural density of the used catalyst, and allows that at the subsequent flotation sorting step, the catalyst grains are separated according to their structural density which is an increasing function of their age, which is not the case for the structural density of a spent, non-regenerated catalyst. Flotation sorting step

[0111] The flow of regenerated catalyst 13 from the catalyst regeneration step 2 is sent to a flotation sorting step 3 comprising bringing said regenerated catalyst 13 into contact with a sorting solvent having a density chosen so as to separate at least a heavy fraction of regenerated catalyst 14 and a light fraction of regenerated catalyst 15.

[0112] The light fraction is capable of being recycled to hydroconversion step 1 in at least one hydroconversion reactor operating in an ebullated bed in the presence of a catalyst and hydrogen.

[0113] By sorting solvent is meant a liquid suitable for the separation of solid particles by flotation. Said sorting solvent used at this stage is detailed below.

[0114] The flotation sorting step is advantageously implemented by a flotation sorting unit which is connected, preferably fluidically, to the hydroconversion catalyst regeneration unit. However, implementation in a remote manner, i.e. with relocated regeneration and flotation sorting units (not on the same site) would not go beyond the scope of the present invention.

[0115] The regenerated catalyst 13 from the regeneration step 2 can be transported by any means of transporting granular material from the regeneration unit to the flotation sorting unit.

[0116] Preferably, said transport is carried out using a fluid.

[0117] According to one or more embodiments, the regenerated catalyst 13 resulting from the regeneration step 2 can be transported by pneumatic transport to the flotation sorting unit.

[0118] According to one or more other embodiments, the regenerated catalyst 13 resulting from the regeneration step 2 can be suspended in a liquid for its transport to the flotation sorting unit, preferably in the sorting solvent used in the flotation sorting step.

[0119] Thus, the regeneration step is preferably carried out in the regeneration unit fluidly connected to the sorting unit in which the flotation sorting step is carried out, and the regenerated catalyst is transferred from the regeneration unit to the sorting unit, preferably by pneumatic transport or by transport in the form of a suspension comprising a transport liquid, which is preferably the sorting solvent used in the flotation sorting step.

[0120] The regenerated catalyst 13 is introduced into the separation unit which comprises a tank for bringing the regenerated catalyst into contact with the sorting solvent and separation means for separating at least two fractions resulting from the sorting: the heavy fraction of ca regenerated catalyst 14 and the light fraction of regenerated catalyst 15.

[0121] The flotation sorting step makes it possible to separate the grains of the regenerated catalyst in a liquid medium according to their structural density, according to the principle of Archimedes' thrust.

[0122] By light fraction of regenerated catalyst is meant a fraction of regenerated catalyst whose structural density (average structural density of the catalyst grains of said fraction) is lower than the density of the sorting solvent, and by heavy fraction of regenerated catalyst is meant a fraction of regenerated catalyst whose structural density (average structural density of the catalyst grains of said fraction) is higher than the density of the sorting solvent.

[0123] Intrinsically to flotation sorting, the sorting solvent has a density chosen so that a portion of the solid particles float on the surface of the liquid, i.e. a portion of the particles has a structural density lower than the density of the liquid, which allows the separation of said portion from the rest of the particles immersed in the liquid, which can also accumulate, at least in part, at the bottom of the tank if the structural density of the particles is greater than that of the liquid.

[0124] Thus, the sorting solvent is advantageously chosen so that its density is greater than the structural density of the fresh catalyst (not loaded with metals from the feedstock during hydroconversion) from which the spent catalyst originates. In this way, it is ensured that the regenerated catalyst grains, having a content of metals deposited during hydroconversion which varies from one grain to another, can be separated according to their metal content, since the deposited metals increase their structural density, as already explained above.

[0125] Preferably, the density of the sorting solvent is chosen so that the light fraction of regenerated spent catalyst 15 comprises a rate of metals deposited during the hydroconversion step less than or equal to 15% by mass relative to the mass of the fresh catalyst.

[0126] The structural density of a fresh catalyst grain (not loaded with metals) is generally between 2.0 g / cm3 and 3.5 g / cm3, and more frequently between 2.5 g / cm3 and 3.0 g / cm3.

[0127] The density of the sorting solvent is preferably between 2.1 g / cm3 and 4.5 g / cm3, preferably between 2.6 g / cm3 and 3.5 g / cm3, preferably between 2.8 g / cm3 and 3.4 g / cm3.

[0128] The sorting solvent is therefore a heavy solvent, which may comprise one or more chemical compounds. Without constituting an exhaustive list, the sorting solvent may comprise, and be constituted by, diiodomethane (CH2L), or a mixture of diiodomethane and chloroform (CHC13), or an aqueous Cleirici solution comprising a mixture of thallium formate and thallium malonate in equal parts. densities of the chemical compounds cited are given below: Density of diiodomethane (CH2I2): 3.32 g / cm3 Density of chloroform (CHC13): 1.48 g / cm3 Density of an aqueous solution of Cleirici: 4.25 g / cm3

[0129] Due to the different structural densities of the catalyst grains, those having a higher structural density than the liquid tend to settle to the bottom of the vessel, while those having a lower structural density float and accumulate at the top of the vessel.

[0130] According to one or more embodiments, the density of the sorting solvent is fixed during the flotation sorting step so as to separate only two fractions of regenerated catalyst consisting of the heavy fraction of regenerated catalyst and the light fraction of regenerated catalyst. Thus, the only fraction of interest which is the light fraction of regenerated catalyst having a still interesting catalytic activity can be recycled in at least one hydroconversion reactor to the hydroconversion step of the hydroconversion process.

[0131] According to one or more embodiments, the composition of said sorting solvent is modified during the flotation sorting step so that the density of said sorting solvent varies over time to separate one or more additional fractions of regenerated catalyst. It is thus possible to separate more than two fractions of regenerated catalyst which have different deposited metal levels, which can be used, for example, to analyze the catalyst used in the hydroconversion, or be useful for recycling different fractions in different reaction zones or hydroconversion reactors. According to this or these embodiments, the regenerated catalyst fractions can be separated sequentially: a composition of the sorting solvent is fixed (for example initially) to separate two fractions, i.e. a light fraction with a structural density lower than the density of the liquid and a heavy fraction with a density higher than the density of the liquid, one of the two fractions being removed from the tank, then the composition of the sorting solvent is modified, thus modifying its density, to separate two fractions again, a light fraction and a heavy fraction which will be located in two distinct zones of the tank (zones located at different levels of the tank), etc., until the desired number of regenerated catalyst fractions is separated. The variation in the composition of the sorting solvent is advantageously carried out by adding a chemical compound with a density different from the chemical compound(s) already present in the sorting solvent, in order to vary the density of the sorting solvent. Preferably, a sorting solvent is initially chosen such that its density is greater than the structural density of the regenerated catalyst, i.e. greater than the structural density of the regenerated catalyst grains most loaded with deposited metals, and modifies the composition of the sorting solvent during the sequence step as described above so as to lower its density. All of the regenerated catalyst grains float at the start of the sorting step because their structural density is lower than the density of the initial sorting solvent (composition at time zero), then lowering the density of the sorting solvent by modifying its composition to a given density will cause some of the grains to fall according to their structural density each, to form a heavy fraction and a light fraction. The heavy fraction can be withdrawn from the tank and the operation can be repeated to separate two fractions again and withdraw the new heavy fraction. Alternatively, it is possible to increase the density of the sorting solvent by modifying its composition, and choose a density of the initial sorting solvent less than or equal to the structural density of the regenerated catalyst (and greater than the structural density of the fresh catalyst). In this case, increasing the density of the sorting solvent by modifying its composition to a given density will cause a portion of the grains whose structural density is less than the density of the modified sorting solvent to float, to form a light fraction, the other heavy fraction remaining at the bottom or in suspension in the tank, and the light fraction can be withdrawn from the tank. The operation can then be repeated to separate two fractions again and withdraw the new light fraction.

[0132] The collection of the heavy and light fractions of regenerated catalyst can be done separately. Any collection means known in the field of flotation sorting can be used by those skilled in the art to separately collect the separated fractions. The following devices, without being exhaustive, can for example be used to collect the light fraction: any type of mechanical recovery device, for example a screw conveyor, an overflow recovery device, a recovery system comprising one or more conduits positioned at the top of the tank and possibly means for controlling the flow rate of the withdrawn light fraction. The collection of the heavy fraction can also be done by any suitable recovery device, such as a recovery system comprising one or more conduits positioned at the bottom of the tank and preferably also comprising means for controlling the flow rate of the withdrawn heavy fraction.

[0133] The flotation sorting step can be carried out continuously or discontinuously (by “batch”).

[0134] According to one or more embodiments, the sorting by flotation is carried out continuously, and comprises the introduction of the regenerated catalyst by gravity from the top of a tank, for example with a conical bottom, containing the sorting solvent. The heavy fraction of regenerated catalyst is recovered at the bottom of the tank. A screw conveyor makes it possible to recover the light fraction of regenerated catalyst which floats on the surface of the sorting solvent. sorting and transporting it to another collection point.

[0135] Advantageously, the sorting step is carried out at atmospheric pressure and at room temperature.

[0136] According to one or more embodiments, the flotation sorting is carried out discontinuously, and the collection of the light fraction of the regenerated catalyst is carried out by draining the sorting solvent from the tank.

[0137] According to one or more embodiments, one or more of the regenerated catalyst fractions resulting from the sorting are dried, and preferably at least the regenerated light fraction intended for recycling is dried. Optionally, the regenerated catalyst fractions, and preferably at least the light fraction, are washed with another solvent before the step of drying the collected regenerated catalyst fraction(s). The drying step, and optionally washing before drying, can be carried out using dedicated equipment. In the case of a flotation sorting step implemented discontinuously, it is possible to use the flotation capacity to carry out washing and drying in a single piece of equipment. Drying can be carried out with hot air, typically between 100°C and 300°C, for example in an oven at 200°C. Drying can advantageously be carried out in a fluidized bed.

[0138] The light fraction of regenerated catalyst 15 is advantageously recycled into at least one ebullated bed hydroconversion reactor. The heavy fraction of regenerated catalyst is preferably purged from the hydroconversion process. Said heavy fraction of regenerated catalyst 14 can also be sent to a rejuvenation step to extract the metallic contaminants (metal deposition), with a view to also recycling said fraction in at least one ebullated bed hydroconversion reactor.

[0139] Plant for treating a spent hydroconversion catalyst

[0140] According to another aspect, the present invention relates to an installation for treating a used hydroconversion catalyst allowing the implementation of the method for treating used hydroconversion catalyst, said installation comprising: - a unit for regenerating said spent hydroconversion catalyst comprising a reactor for combustion of coke from the spent hydroconversion catalyst to form a regenerated catalyst; - a flotation sorting unit for the regenerated catalyst connected, preferably fluidically, to said catalyst regeneration unit, said flotation sorting unit comprising a tank for bringing the regenerated catalyst into contact with a sorting solvent and means for separating a heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst.

[0141] The description of the regeneration and flotation sorting units has been given above. in connection with the description of the corresponding steps above, and is not repeated here.

[0142] The spent catalyst treatment facility may further comprise a first washing and drying unit for the spent catalyst stream 12 withdrawn from the hydroconversion reactor, connected to the regeneration unit. Said first washing and drying unit may comprise a fluidized bed reactor for drying the spent catalyst.

[0143] Said first washing and drying unit can also be used independently for washing and drying the regenerated catalyst fractions resulting from the flotation sorting step, and in particular for the light fraction of the regenerated catalyst intended to be recycled in at least one hydroconversion reactor. Alternatively, the spent catalyst treatment facility can comprise a second washing and drying unit dedicated to washing and drying the regenerated catalyst fractions resulting from the flotation sorting step, different from the first unit. Hydroconversion process

[0144] According to another aspect, the present invention relates to a hydroconversion process comprising: - hydroconversion step 1 of the hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and the hydroconversion catalyst and; - a step of withdrawing from said hydroconversion reactor the flow of said spent hydroconversion catalyst 12 and introducing into said hydroconversion reactor a make-up comprising the flow of fresh hydroconversion catalyst 11 and the flow of recycled hydroconversion catalyst 15; - a step of treating said withdrawn spent hydroconversion catalyst stream 12 by a treatment method according to the invention as described above, producing the light fraction of regenerated hydroconversion catalyst forming the recycled hydroconversion catalyst stream 15.

[0145] The treatment of the withdrawn spent catalyst 12 has been described extensively above and is not repeated here. Charge

[0146] The hydrocarbon feedstock sent to the hydroconversion is a heavy feedstock comprising metals. It preferably contains a fraction of at least 50% by weight having a boiling point of at least 300°C, preferably at least 350°C, preferably at least 375°C, at least 450°C, preferably at least 500°C, and even more preferably at least 540°C.

[0147] The hydrocarbon feedstock is typically a feedstock of fossil origin.

[0148] Preferably, the hydrocarbon feedstock comprises, and may consist of, one of the following feedstocks, alone or in a mixture: a crude oil, a synthetic crude oil, a coal tar, a bitumen from oil sands, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion or hydrotreatment or hydrocracking or hydroconversion unit or from a direct coal liquefaction unit (for example operated using the H-Coal® process), a vacuum distillate obtained directly from crude oil or from a cut from a fluidized bed catalytic cracking unit (also called FCC for Fluid Catalytic Cracking in English terminology) or from a hydrocracking unit or from a hydroconversion unit or from a coking unit or from a visbreaking unit, a vacuum distillate from the direct liquefaction of coal, aromatic cuts extracted from a lubricant production unit, a deasphalted oil (also called DAO for Deasphlated oil in Anglo-Saxon terminology) or an asphalt from a deasphalting unit.

[0149] The charges cited of the vacuum distillate type, aromatic cuts and deasphalted oils can enter into the composition of the hydrocarbon charge, preferably in a minority manner with another type of charge cited above.

[0150] The charges cited are liquid under the operating conditions of hydroconversion.

[0151] Preferably, the hydrocarbon feedstock comprises, and may consist of, one of the following feedstocks, alone or in a mixture: a crude oil, a synthetic crude oil, a coal tar, a bitumen from oil sands, a heavy oil from oil shale, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of a crude oil, an atmospheric residue or a vacuum residue from the atmospheric or vacuum distillation of an effluent from a thermal conversion unit or hydrotreatment or hydrocracking or hydroconversion or a direct coal liquefaction unit (for example operated according to the H-Coal® process), a vacuum residue from the vacuum distillation of a crude oil.

[0152] Preferably, the hydrocarbon feedstock comprises, and may consist of, a vacuum residue from the vacuum distillation of a crude oil.

[0153] The hydrocarbon feedstock contains metals, and typically other impurities such as sulfur, nitrogen, Conradson carbon and asphaltenes, particularly C7 asphaltenes which are insoluble in heptane. The metal contents may be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight. For example, the cumulative nickel and vanadium content is greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight, or even greater than or equal to 150 or 200 ppm by weight. 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 level of C7 asphaltenes (heptane-insoluble compounds according to ASTM D 6560, also corresponding to NF T60-115) can be at least 1% by weight and is often greater than or equal to 3% by weight (with the exception of a feedstock comprising mainly DAO). C7 asphaltenes are compounds known to inhibit the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly called coke, and by their tendency to produce sediments which can severely limit the operability of hydroconversion units. The Conradson carbon content may be greater than or equal to 3% by weight, or 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 conditions of temperature and pressure.

[0154] These contents are expressed in % by weight of the total weight of the hydrocarbon feedstock.

[0155] According to one or more embodiments, a co-feedstock may be sent to the hydroconversion step with the hydrocarbon feedstock as described above, preferably said co-feedstock being in the minority compared to the hydrocarbon feedstock and for example represented less than 30% by mass, preferably less than 20% or 10% compared to the hydrocarbon feedstock.

[0156] Preferably, the co-charge comprises, and may consist of, one of the co- following charges, alone or in mixture: - a vegetable and / or animal oil or fat, typically containing triglycerides and / or free fatty acids and / or esters, which may be crude or refined. Vegetable oils may be, for example, derived from rapeseed, soybean, sunflower, palm, palm kernel, olive, copra, castor oil, cottonseed, peanuts, flax, crambe, Purghères (jatropha), including all oils obtained by genetic modification or hybridization. Vegetable and animal oils may be waste oils, such as frying oils, or any used oil or fat from the catering industry. Animal oils and fats may be, for example, fish oils, tallow, lard. - biomass such as algae, lignocellulosic biomass, or one or more constituents of lignocellulosic biomass chosen from the group formed by cellulose, hemicellulose and lignin. - any product or mixture of products or cuts of products resulting from the thermochemical or hydrothermal conversion of biomass. - plastics and / or solid recovered fuels (SRF), the plastics typically being production scrap and / or waste (e.g. household waste, construction waste, electrical and electronic equipment waste), and preferably comprising polymers of alkenes, dienes, vinyls, styrenics, polyesters, and / or polyamides, and more preferably polyolefins, such as polyethylene (PE), polypropylene (PP), or copolymers of ethylene and propylene. - a pyrolysis oil from plastics and / or solid recovered fuels (SRF).

[0157] The co-feed may undergo a pre-treatment step, for example a mechanical and / or chemical treatment, such as drying and / or roasting and / or grinding for biomass, or grinding and / or washing and / or drying and / or liquefaction by heating and / or dissolution for plastics, before being sent to the hydroconversion step.

[0158] The co-feed and the hydrocarbon feed may be fed independently or mixed into the hydroconversion reactor. In the remainder of the description, no reference is made to the co-feed, it being understood that what is described for the hydroconversion of the feed applies to the co-feed treated with the feed. Hydroconversion stage

[0159] The hydrocarbon feedstock is introduced into a hydroconversion reactor of the hydroconversion section, together with hydrogen (stream not shown). Said reactor comprises the hydroconversion catalyst.

[0160] Hydroconversion step 1 is carried out under conditions making it possible to obtain a hydroconverted effluent, which contains the conversion products. The hydroconverted effluent has in particular a reduced content (relative to the feed) of hydrocarbons. having 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. Said hydroconverted effluent also has a reduced content, relative to the feed, of metals, and / or sulfur, and / or nitrogen, and / or Conradson carbon, and / or asphaltenes, and / or other impurities initially contained in the feed, depending on the reactions carried out in the hydroconversion reactor and the composition of the feed. In particular, said hydroconverted effluent may advantageously have a reduced content, relative to the feed, of metals, sulfur, nitrogen, Conradson carbon, and asphaltenes. The hydroconversion step is preferably carried out under an absolute pressure of between 2 MPa and 38 MPa, more preferably between 5 MPa and 25 MPa, and even more preferably between 6 MPa and 20 MPa, at a temperature of between 300°C and 550°C, more preferably between 350°C and 500°C, preferably between 370°C and 450°C, and even more preferably between 400°C and 450°C. The hourly space 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 liquid hourly space velocity (LHSV) or hourly space velocity (HSV) according to English terminology, is defined here as the ratio between the hourly volume flow rate of the liquid feedstock (sent to the hydroconversion step) and the volume of each hydroconversion reactor. According to a preferred implementation, the WH is between 0.1 h 1 and 10 h 1, more preferably between 0.1 h 1 and 5 h 1, even more preferably between 0.15 h 1 and 2 h *, and even more preferably between 0.15 h 1 and 1 h 1. According to another implementation, the overall WH, i.e. the liquid feed flow rate sent to step b) relative to the volume of all the reactors if several hydroconversion reactors are implemented in step b), is between 0.05 h 1 and 0.09 h 1. The amount of hydrogen mixed with the feedstock is preferably between 50 and 5000 normal cubic meters (Nm3) per cubic meter (m3) of liquid feedstock, preferably between 100 Nm3 / m3 and 2000 Nm3 / m3 and very preferably between 200 Nm3 / m3 and 1000 Nm3 / m3.

[0161] The hydroconversion section comprises one or more reactors operating in an ebullated bed and containing a hydroconversion catalyst, the reactors being able to be arranged in series and / or in parallel. At this stage, the catalyst is therefore maintained in the ebullated bed reactor(s), as described for the H-Oil® process, for example, in patents US4521295 or US4495060 or US4457831 or US4354852, in the article Aiche, March 19-23, 1995, Houston, Texas, article number 46d, "Second generation ebullated bed technology", or in chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" from the book "Catalysis by Transition Metal Sulphides", Technip Editions, 2013. Each reactor advantageously includes a recirculation pump which makes it possible to maintain the porous supported solid catalyst in a bubbling bed by continuous recycling of at least part of a liquid fraction withdrawn from the upper part of the reactor and reinjected into the lower part of the reactor.

[0162] The ebullated bed reactor preferably comprises at least one inlet located at or near the lower portion of the reactor through which the feedstock is introduced together with the hydrogen, and an outlet at or near the upper portion of the reactor through which the hydroconverted effluent is withdrawn from the reactor. The reactor further advantageously comprises at least one inlet and one outlet for injecting catalyst makeup and withdrawing spent catalyst, as described in more detail below in the catalyst withdrawal and makeup step. The ebullated bed reactor further comprises an expanded catalyst zone comprising the catalyst (the ebullated bed). The ebullated bed reactor also comprises a lower catalyst-free zone located below the expanded catalyst zone, and an upper supported catalyst-free zone located above the expanded catalyst zone.The feed in the ebullated bed reactor continuously recirculates from the upper supported catalyst-free zone to the lower supported catalyst-free zone by means of a recycle conduit in communication with a boiling pump. At the top of the recycle conduit there is preferably a funnel-shaped recycle cup through which the feed is drawn from the upper supported catalyst-free zone. The internal recycled feed is mixed with "fresh" feed and additional hydrogen gas.

[0163] Because the catalyst is kept stirring by significant liquid recycling, the pressure drop across the reactor remains low and constant, and the reaction exotherms are quickly averaged across the catalytic bed, which is therefore almost isothermal and does not require, for example, the injection of cooling flows (“quenches” in English). The use of such ebullated bed reactors also makes it possible to operate under more severe conditions than, for example, those operated in a fixed catalyst bed reactor, allowing for better overall conversion of the feedstock. Another advantage linked to the use of ebullated bed reactors is the long cycle time of the hydroconversion unit (without stopping the unit to replace the catalyst(s)), in particular thanks to the catalyst withdrawal and injection system allowing the continuous replacement of used catalyst without stopping the hydroconversion unit made possible by the operation of such a type of reactor.

[0164] The hydroconversion catalyst has been described above in connection with the method of treating the spent hydroconversion catalyst, and its description is not repeated here.

[0165] According to one or more embodiments, the hydroconversion process comprises a second hydroconversion step (not shown in [Fig.l]) in at least one second ebullated bed reactor, of part or all of the hydroconverted effluent obtained at the end of hydroconversion step 1, or optionally of a heavy cut resulting from an intermediate separation step described below. The second hydroconversion step is carried out so as to produce a second hydroconverted effluent. Said second hydroconverted effluent advantageously contains a greater quantity of conversion products than the hydroconverted effluent from hydroconversion step 1, and in particular an even lower content of hydrocarbons having a boiling point of at least 300°C, or at least 350°C, 375°C, 450°C, 500°C, or even 540°C depending on the nature of the feedstock. The second hydroconverted effluent may be provided with a reduced Conradson carbon residue, and optionally a reduced quantity of metals, and / or sulfur, and / or nitrogen, and / or asphaltenes.

[0166] The second hydroconversion step is carried out in a manner similar to that described for hydroconversion step 1. This applies in particular to the operating conditions, the equipment used, the hydroconversion catalyst used, with the exception of the details mentioned below.

[0167] In the second hydroconversion step, the operating conditions may be similar or different from those of hydroconversion step 1, the temperature remaining in the range between 300°C and 550°C, more preferably between 350°C and 500°C, more preferably between 370°C and 450°C, even more preferably between 400°C and 450°C, even more preferably between 400°C and 440°C, and even more preferably between 410°C and 435°C, and the amount of hydrogen introduced into the reactor 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 hydroconversion step 1.

[0168] The operating temperature in the second hydroconversion stage may be higher than the operating temperature in hydroconversion stage 1. This may allow for more complete conversion of the feedstock not yet converted. Hydroconversion of liquid products from hydroconversion stage 1 and feedstock are enhanced, as are hydrotreatment reactions such as hydrodesulfurization and hydrodenitrogenation, among others. Operating conditions are chosen to minimize the formation of solids (e.g., coke).

[0169] According to one or more embodiments, the hydroconversion process comprises an intermediate separation step, between the hydroconversion step 1 of the feedstock and the second hydroconversion step, which separates part, or all, of the hydroconverted effluent from the hydroconversion step 1, to produce at least two cuts, including a heavy cut boiling mainly at a temperature greater than or equal to 350°C. The other cut(s) are one or more light and intermediate cut(s). The light cut thus separated mainly contains gases (H2, H2S, NH3, and CrC4), naphtha (or gasoline, cut which boils at a temperature below 150°C), kerosene (cut which boils between 150°C and 250°C), and at least part of the diesel (or gas oil, fraction which boils between 250°C and 350°C, or even 375°C). The light cut can be sent at least partially to a fractionation unit (not shown in [Fig.l]) where the light gases are extracted from said light cut, for example by passing through an expansion drum. The gaseous hydrogen thus recovered, which may have been sent to a purification and compression installation, can advantageously be recycled to hydroconversion step 1, and / or to the second hydroconversion step if it is implemented. The recovered hydrogen gas can also be used in other refinery facilities.

[0170] The optional separation step is carried out in a separation section which comprises any separation means known to a person skilled in the art. Said separation section may comprise one or more flash drums arranged in series, and / or one or more steam and / or hydrogen stripping columns, and / or an atmospheric distillation column, and / or a vacuum distillation column, and preferably consists of a single flash drum, commonly referred to as a "hot separator".

[0171] Conventionally, the hydroconverted effluent from hydroconversion step 1 or from the second hydroconversion step then undergoes, at least in part, a fractionation step, which separates part or all of said hydroconverted effluent into several fractions including at least one heavy liquid product boiling predominantly at a temperature above 350°C, preferably above 500°C, and more preferably above 540°C. The heavy liquid product contains a portion boiling at a temperature above 540°C, called the residual fraction (or vacuum residue), which is the unconverted portion. The heavy liquid product may contain a portion of the diesel fraction boiling between 250°C and 375°C and a portion boiling between 375°C and 540°C (also called the vacuum distillate). This fractionation 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 comprising hydrogen and . H2S which can be sent to a hydrogen treatment and recycling stage. The fractionation section comprises any separation means known to those skilled in the art, such as one or more flash drums arranged in series, and preferably a chain of at least two successive flash drums, one or more steam and / or hydrogen stripping columns, an atmospheric distillation column, a vacuum distillation column, for example an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

[0172] It is possible to recycle in hydroconversion step 1 part of the heavy liquid product resulting from the fractionation, and / or part or all of another effluent resulting from a subsequent treatment (e.g. deasphalting) of the heavy liquid product resulting from the fractionation.

[0173] Hydroconversion catalyst withdrawal and addition step

[0174] The hydroconversion process according to the invention comprises a step of withdrawing a spent catalyst stream 12 from the hydroconversion reactor and introducing into the reactor a make-up comprising a fresh catalyst stream 11 and a recycled catalyst stream 15.

[0175] The principle of withdrawing spent catalyst and injecting a catalyst supplement, 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 spent, can be partially withdrawn, preferably at the bottom of the reactor, and replaced by introducing, either at the top or at the bottom of the reactor, a fresh catalyst supplement, and / or spent catalyst, but with a catalytic activity greater than the spent catalyst to be replaced, and / or regenerated catalyst, and / or rejuvenated catalyst (catalyst from a rejuvenation zone in which the majority of the deposited metals are eliminated, before sending the rejuvenated catalyst to a regeneration zone in which the carbon and sulfur it contains are eliminated, thus increasing the activity of the catalyst).

[0176] According to an essential aspect of the hydroconversion process according to the invention, the make-up comprises a flow of fresh catalyst 11 and a flow of recycled catalyst 15 which is constituted by the light fraction of regenerated catalyst resulting from a stage of treatment of the spent catalyst in accordance with the treatment process according to the invention including a regeneration of the spent catalyst and then sorting by flotation.

[0177] The replacement of used catalyst is preferably carried out at regular time intervals, and preferably in bursts or almost continuously.

[0178] The withdrawal and injection of the make-up are carried out using a withdrawal and injection device advantageously adapted to continuous operation of the hydroconversion stage.

[0179] By this operation of withdrawal / injection of the catalyst, it is therefore not necessary to stop the unit to change the used catalyst, nor to increase the temperatures reaction temperatures along the cycle to compensate for deactivation. In addition, working at constant operating conditions allows for consistent yields and product qualities throughout the cycle.

[0180] According to one or more embodiments, the make-up comprises between 5% and 35% by weight of the recycled catalyst stream 15, preferably between 10% and 30% by weight.

[0181] In other words, the recycled catalyst flow 15 from the make-up preferably constitutes between 5% and 35% by weight, preferably between 10% and 30% by weight, of the withdrawn spent catalyst flow 12.

[0182] Such recycling of spent catalyst obtained during the spent catalyst treatment step makes it possible to reduce the overall consumption of fresh catalyst during the hydroconversion process, compared to a catalyst supplement formed exclusively of fresh catalyst, which makes it possible to reduce the operating costs of the process. Such recycling of spent catalyst can also increase the catalytic activity during the hydroconversion, at the same level of fresh catalyst supplement. Examples

[0183] The examples below aim to show certain performances of the process for treating a spent hydroconversion catalyst and of the hydroconversion process according to the invention.

[0184] Example 1 presents laboratory experiments illustrating the performance of flotation sorting of a regenerated spent catalyst, and in particular in comparison with a non-regenerated spent catalyst.

[0185] Example 2 presents a simulated industrial case of a hydroconversion process according to the invention, implementing the recycling of a fraction of regenerated spent catalyst obtained by a spent catalyst treatment process according to the invention. Example 1

[0186] This Example 1 relates to laboratory flotation tests on a hydroconversion catalyst as used in an H-Oil® process.

[0187] [Fig.2] illustrates the flotation sorting device implemented in the laboratory. The device 20 comprises a separating funnel 21, positioned above a recovery tank 22.

[0188] Operating mode:

[0189] In the device 20, the catalyst grains 23 are introduced into diiodomethane (CH2L) which has a very high density of 3.32 g / cm3. All of the catalyst grains then end up floating at the start of the experiment because their structural density is lower. Then chloroform 24 (CHC13), with a density of 1.48 g / cm3, is gradually added to lower the density of the mixture 25 and cause the grains to fall according to their structural density. A light fraction of catalyst 26 floats on the surface and a heavy fraction of catalyst 27 accumulates at the bottom of the ampoule. This heavy fraction of catalyst can be withdrawn from the ampoule via the tap located at the end of the narrow tube in the lower part of the ampoule and recovered in the tank 22.

[0190] Three types of catalysts are tested according to the procedure described above: - Catl: ​​a fresh hydroconversion catalyst of the NiMo / alumina type having a NiO content of 4% by weight and a MoO3 content of 10% by weight, the percentages being expressed relative to the total mass of the catalyst; - Cat2: the used catalyst from the fresh catalyst (used in a H-Oil® type hydroconversion process, not regenerated (no elimination of coke by combustion); - Cat3: the spent catalyst from the fresh catalyst (used in a H-Oil® type hydroconversion process, and regenerated by combustion of the coke. The combustion of the coke is carried out in a muffle furnace, in air. The spent catalyst is left there for 2 hours at 250°C then 2 hours at 550°C.

[0191] Table 1 below shows some properties of these three catalysts. The unregenerated spent catalyst Cat 2 contains approximately 30% by weight of deposited metals (deposited metal content) and approximately 33% by weight of deposited coke, expressed relative to the weight of fresh catalyst Cat1. These contents are averages, because the spent catalyst contains catalyst grains of different ages and therefore different metal and coke contents.

[0192] [Tables 1] Catalyst Catl (fresh) Cat2 (used non-regenerated) Cat3 (used regenerated) Vanadium deposited (average) % weight 0 25.3 25.3 Ni deposited (average) % weight 0 4.9 4.9 Ni+V deposited (average) % weight 0 30.2 30.2 Carbon deposited (average) % weight 0 33.5 < 1

[0193] [Fig.3] shows the mass recovery results obtained by flotation for the different catalysts: on the abscissa is the density of the sorting solvent “D” (CH2I2 / CHC13 mixture), and on the ordinate is the cumulative recovery of the catalyst in weight percentage “R”. The points and associated curves are identified by the references Cl, C2, C3 respectively for the fresh catalysts Cat1, spent non-regenerated Cat2 and spent regenerated Cat3.

[0194] Table 2 and Table 3 below show the different separated fractions by flotation for the unregenerated spent catalyst Cat2 and the regenerated spent catalyst Cat3, indicating for each fraction of catalyst recovered its density range, its mass fraction relative to the total mass of catalyst tested, and the rate of deposited metals (Ni, V, and Ni+V). The rate of deposited metals is expressed as a weight percentage relative to the weight of the fresh catalyst. The weight fraction recovered by flotation is expressed as a weight percentage relative to the weight of the spent catalyst (Cat2 for Table 2 and Cat3 for Table 3).

[0195] [Tables2] Density range (g / cm3) Cat2: Weight fraction recovered by flotation (% wt) V deposited (% wt) Ni deposited (% wt) Ni+V deposited (% wt) 2.8-2.97 4.7 31.8 7.3 39.1 2.73-2.8 18.2 29.2 7.0 36.2 2.66-2.73 25.2 27.2 6.6 33.8 2.60-2.66 26.1 24.7 5.8 30.5 2.55-2.60 16.2 20.9 5.1 26.0 2.46-2.55 9.6 14.7 3.5 18.2

[0196] [Tables3] Density range (g / cm3) Cat3: weight fraction recovered by flotation (% wt) V deposited (% wt) Ni deposited (% wt) Ni+V deposited (% wt) >3.33 54.4 37.4 9.4 46.8 3.19-3.33 15.8 14.6 3.6 18.2 3.07 - 3.19 13.7 8.1 2.0 10.1 2.88 - 3.07 16.1 2.5 0.6 3.1

[0197] Fresh catalyst Catl:

[0198] [Fig.3] shows that 95% of the fresh catalyst Catl is recovered between 2.88 and 2.97 g / cm3. The dispersion in structural density is low because the grains of the fresh catalyst are relatively uniform at the start (before any use in hydroconversion).

[0199] Unregenerated spent catalyst Cat2:

[0200] [Fig.3] shows that for catalyst Cat2, the density dispersion is greater than that of fresh catalyst Catl due to the age distribution of the grains of Cat2 catalyst. The average structural density is also lower than that of the fresh catalyst due to the significant presence (33.5% by weight) of a low-density coke deposit.

[0201] Table 2 shows that separation by metal content (and therefore by age) was not very effective in the case of the unregenerated spent catalyst Cat2: the densest fraction contains 39.1% by weight of deposited nickel and vanadium and the least dense fraction still contains 18.2% by weight, meaning that the least dense (lightest) fraction is not only composed of "young" catalyst. Moreover, this lightest fraction represents only 9.6% by weight of the total catalyst, and generating an even less dense fraction by flotation would lead to too small a quantity to be recycled to represent a real interest with regard to the hydroconversion process.

[0202] Regenerated spent catalyst Cat3:

[0203] [Fig.3] shows that the average structural density of catalyst C3 is higher than that of fresh catalyst Cl, due to the presence of metal deposits which have a higher structural density than catalyst CL. Moreover, a significant mass fraction of the C3 catalyst grains (more than 50% by weight) have a structural density greater than 3.33 g / cm3 (higher than the density of diiodomethane used in the flotation tests). It can also be observed that regeneration has broadened the structural density distribution of the catalyst grains.

[0204] Table 3 shows a large difference in metal content (Ni+V) between the least dense fraction (3.1% by weight relative to the fresh catalyst Cl) and the most dense (46.8% by weight relative to the fresh catalyst Cl). The treatment process according to the invention, including regeneration prior to sorting by flotation, allows for a significantly improved separation of the used catalyst. The treatment according to the invention makes it possible in particular to obtain a very young catalyst fraction that can be recycled to the hydroconversion process. According to this test, it is possible, for example, to choose to recycle all of the catalyst grains having a structural density of less than 3.19 g / cm3, representing a mass fraction of 29.8% by weight of the total mass of the regenerated used catalyst C3 sent for sorting.Recycling such a fraction would make it possible to reduce by approximately 30% the fraction of fresh catalyst for catalyst top-up in the reactor, and consequently the operating costs (OPEX) of the hydroconversion process. Example 2

[0205] In this example, we consider an industrial hydroconversion unit implemented by a H-Oil® type hydroconversion process, treating a hydrocarbon feedstock at a rate of 50,000 bbl / day, said feedstock being a straight-run RSV vacuum residue (RSV-SR) of Arabian Heavy type. The main characteristics of the feedstock are given in Table 4 below.

[0206] [Tables4] Unit Value Density g / cm3 1.024 Content 540°C+ % weight 82.0 Sulphur % weight 4.89 Ni+V ppm weight 218 CCR % weight 21.6

[0207] The hydroconversion unit comprises two reactors in series operating at a temperature of approximately 430°C. Table 5 below gives the performances in conversion of heavy cuts (540°C+), in desulfurization (HDS), in demetallation (HDM - Ni+V) and in reduction of carbon conradson (HDCCR), without the use of a catalyst supplement comprising recycled spent catalyst. The catalyst supplement is formed solely by fresh catalyst.

[0208] [Tables5] Performance Value Conversion 540°C+ (% weight) 78.4 HDS (% weight) 87.3 HDM - Ni+V (% weight) 90.9 HDCCR (% weight) 73.6

[0209] The catalyst replacement rate is 3.9 t / day on each reactor. This leads in particular to an average content of Ni+V deposited of 30% by weight (relative to the total weight of the fresh catalyst) on the spent catalyst extracted from the first reactor. In this spent catalyst, approximately 20% by weight of the grains have a residence time in the reactor of less than 10 days, and are therefore still very active (content of deposited metals < 15% by weight relative to the total weight of fresh catalyst).

[0210] A step of treating the withdrawn spent catalyst is carried out, according to the method of treating spent catalyst according to the invention. A light fraction of regenerated catalyst, which has a deposited metal content of less than 15% by weight (relative to the total weight of fresh catalyst) is obtained from the sorting.

[0211] During the catalyst withdrawal and top-up step, the top-up carried out in the first reactor comprises fresh catalyst and said light fraction of the regenerated catalyst resulting from the treatment process according to the invention.

[0212] Thanks to the catalyst treatment process according to the invention, a saving of approximately 800 kg of fresh catalyst per day is achieved in the process. hydroconversion. In addition, the impact on the performance of the hydroconversion unit is very low, as shown in Table 6 below, which gives the performance in conversion of heavy cuts (540°C+), desulfurization (HDS), demetallation (HDM - Ni+V) and reduction of conradson carbon (HDCCR), with the use of a catalyst supplement comprising fresh catalyst and a fraction of recycled catalyst consisting of the light fraction of regenerated catalyst, because the recycled catalyst is still very active.

[0213] [Tableauxô] Performance Value Conversion 540°C+ (% weight) 78.3 HDS (% weight) 86.9 HDM - Ni+V (% weight) 90.3 HDCCR (% weight) 73.0

Claims

Claims

1. A method for treating a spent hydroconversion catalyst, comprising: - a regeneration step (2) of said spent hydroconversion catalyst comprising removal of coke from said spent hydroconversion catalyst, preferably by combustion, to form a regenerated catalyst, - a sorting step by flotation (3) of said regenerated catalyst resulting from the regeneration step comprising contacting said regenerated catalyst with a sorting solvent having a density chosen so as to separate at least a heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst, the light fraction being capable of being recycled to a hydroconversion step in at least one hydroconversion reactor operating in an ebullated bed in the presence of a hydroconversion catalyst and hydrogen.

2. Treatment method according to claim 1, the regeneration step (2) is carried out by combustion by contacting said spent hydroconversion catalyst with a regeneration gas stream comprising oxygen at a temperature between 350°C and 600°C, preferably between 400°C and 550°C, preferably between 450°C and 550°C.

3. Treatment method according to any one of the preceding claims, comprising, prior to the regeneration step: - washing the spent hydroconversion catalyst using a washing solvent, preferably said washing solvent being a hydrocarbon solvent, preferably chosen from the list consisting of a gasoline, a diesel, and an aromatic compound, preferably toluene; and - drying said washed spent hydroconversion catalyst by contacting with a drying gas and / or by heating, preferably in contact with an inert gas, and preferably at a temperature between 50°C and 200°C.

4. A treatment method according to any one of the preceding claims, wherein the composition of said sorting solvent is modified during the flotation sorting step so that the density of said sorting solvent varies over time to separate one or more additional fractions of regenerated catalyst.

5. A treatment method according to any one of claims 1 to 3, wherein the density of said sorting solvent is fixed during the flotation sorting step so as to separate only two ca- fractions regenerated catalyst consisting of said heavy fraction of regenerated catalyst and said light fraction of regenerated catalyst.

6. A treatment method according to any one of the preceding claims, wherein the sorting solvent in the flotation sorting step is chosen such that its density is greater than the structural density of a fresh hydroconversion catalyst from which said spent hydroconversion catalyst is derived.

7. Treatment method according to claim 6, in which the density of the solvent is chosen so that the light fraction of regenerated spent catalyst comprises a rate of metals deposited during the hydroconversion step less than or equal to 15% by weight relative to the weight of the fresh hydroconversion catalyst.

8. A treatment method according to any one of the preceding claims, wherein the density of the sorting solvent in the flotation sorting step is between 2.1 g / cm3 and 4.5 g / cm3, preferably between 2.6 and 3.5 g / cm3, preferably is between 2.8 g / cm3 and 3.4 g / cm3.

9. Treatment method according to the preceding claim, in which the sorting solvent in the flotation sorting step comprises diiodomethane, or a mixture of diiodomethane and chloroform, or an aqueous Cleirici solution comprising a mixture of thallium formate and thallium malonate in equal parts.

10. A treatment method according to any one of the preceding claims, wherein the regeneration step is carried out in a regeneration unit fluidly connected to a sorting unit in which the flotation sorting step is carried out, and said regenerated catalyst is transferred from said regeneration unit to said sorting unit, preferably by pneumatic transport or by transport in the form of a suspension comprising a transport liquid, preferably said transport liquid being the sorting solvent used in the flotation sorting step.

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

12. Plant for treating a spent hydroconversion catalyst comprising: - a unit for regenerating said spent hydroconversion catalyst comprising a reactor for burning coke from the spent hydroconversion catalyst to form a regenerated catalyst; - a unit for sorting by flotation of the regenerated catalyst connected, preferably fluidically, to said catalyst regeneration unit, said flotation sorting unit comprising a tank for bringing the regenerated catalyst into contact with a sorting solvent and means for separating a heavy fraction of regenerated catalyst and a light fraction of regenerated catalyst.

13. Hydroconversion process comprising: - a step of hydroconversion (1) of a hydrocarbon feedstock containing metals, in a hydroconversion section comprising at least one hydroconversion reactor operating in an ebullated bed in the presence of hydrogen and a hydroconversion catalyst and; - a step of withdrawing from said hydroconversion reactor a stream of said spent hydroconversion catalyst (12) and introducing into said hydroconversion reactor a make-up comprising a stream of fresh hydroconversion catalyst (11) and a stream of recycled hydroconversion catalyst (15); - a step of treating said withdrawn spent hydroconversion catalyst stream (12) by a treatment method according to any one of claims 1 to 11, producing a light fraction of regenerated hydroconversion catalyst forming said stream of recycled hydroconversion catalyst (15).

14. A hydroconversion process according to claim 13, wherein the make-up comprises between 5% and 35% by weight of said recycled hydroconversion catalyst stream (15), preferably between 10% and 30% by weight.

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

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