BOILING BED OR BOILING-DRIVEN HYBRID HYDROCONVERSION OF A FEED COMPRISING A PLASTIC FRACTION

Abstract

The present invention relates to a method for hydroconversion of a feedstock comprising a plastic fraction (102), in particular from plastic waste, and a heavy hydrocarbon fraction (101), in particular a heavy hydrocarbon fraction containing a portion of at least 50% by weight, preferably at least 80% by weight, having a boiling point of at least 300°C. The hydroconversion uses one or more ebullated bed or hybrid ebullated-entrained bed reactors (20), and preferably two successive hydroconversion stages, in order to produce higher quality materials with a lower boiling point, for example for the production of fuels, while allowing the recovery of plastic waste. Figure 1A to be published

Description

Description Title of the invention: BOILING BED OR BOILING-DRIVED HYBRID HYDROCONVERSION OF A CHARGE CONTAINING A FRACTION PLASTIC technical field

[0001] The present invention relates to the field of charge hydroconversion comprising a plastic fraction, notably from plastic waste, and a heavy hydrocarbon fraction, in particular a heavy hydrocarbon fraction containing a portion of at least 50% by weight, preferably at least 80% by weight, having a boiling point of at least 300°C.

[0002] — The heavy hydrocarbon fraction can be crude oil or be derived from the dis- the production and / or refining of crude oil, typically topped crude oil, a Residue from the atmospheric and / or vacuum distillation of crude oil. This fraction heavy hydrocarbons are associated with a fraction of plastic(s).

[0003] — In particular, the present invention relates to a hydroconversion process of a such a mixed charge, comprising at least one hydroconversion step putting in works one or more reactors operating in a bubbling bed or hybrid bed configuration bubbling-entrained, and preferably two successive hydroconversion stages, in with a view to producing higher quality materials with a lower boiling point, by for example, for fuel production purposes, while allowing the valorization of plastic waste. Previous technique

[0004] — For several years, we have seen the emergence, within the fuel and chemical sectors, processes incorporating products other than traditional petroleum products, for example, products of renewable origin such as lignocellulosic biomass, or even plastic waste products, as a complement or substitute products of fossil origin.

[0005] — For example, US patent 8623102 relating to a liquefaction process is known of biomass selected from algae, lignocellulosic biomass or one or more selected lignocellulosic biomass constituents from the group formed by the cellulose, hemicellulose and / or lignin to produce fuel bases, said process comprising two successive hydroconversion stages under high pressure hydrogen in bubbling bed reactors using a catalyst supported by a hydroconversion-type petroleum residue and a suspension composed of biomass and a solvent. In particular, in the context of a circular economy and waste reduction, there is special attention paid to plastics, which are classically petroleum-derived products, in order to valorize them. This recovery of plastic waste can consist of transforming said plastics, by mechanical and / or chemical means, in order to allow the renewed production of plastics or plastic-based objects. This is then referred to as plastic waste recycling. This recovery of plastic waste can also follow the path of energy recovery, in particular with regard to non-recyclable or difficult-to-recycle plastic waste, as an alternative, in some cases, to landfilling. Typically, energy recovery from plastic waste involves producing energy in the form of electricity and / or heat. For example, it is known to subject plastics from collection and sorting streams to a pyrolysis step to produce, among other things, plastic pyrolysis oils, which are generally burned to generate electricity and / or used as fuel in industrial or district heating boilers. In the field of hydroconversion, specifically the conversion of hydrocarbon feedstocks under high hydrogen pressure into products with lower boiling point ranges than the original feedstock, application WO2020129020 describes a hydroconversion process for a polymer blend based on the use of an entrained catalyst, also known as the "slurry" hydroconversion process. The very small catalyst is dispersed in the reaction medium, distributed uniformly throughout the reactor, and entrained with the products leaving the reactor. According to this process, a plastic blend is treated using slurry technology based on a reactor operating with an entrained catalyst and is transformed into hydrocarbons with a boiling point ranging from 65°C to 175°C, corresponding to a naphtha cut.Ultimately, this is a chemical recycling process for plastic waste, transforming used plastics into a naphtha cut, which is one of the main reagents for plastic production. The feedstock in the slurry hydroconversion process according to application WO2020129020 is a solid mixture of polymers, which can be mixed with a residue under vacuum, and which is introduced as a slurry (suspension of solids) into a reactor operating in an entrained bed configuration. Although slurry processes are known to handle heavy feedstocks and achieve higher conversion rates than other processes, for example, hydroconversion processes using bubbling bed reactors employing a supported catalyst maintained in the reactor, a major drawback of slurry processes lies in the... complex and costly management of the catalyst entrained with the conversion products, in particular its separation from the final products. Objectives and Summary of the Invention The present invention relates to the field of valorization of heavy, difficult-to-valorize loads such as petroleum residues, which generally contain high levels of impurities such as metals, sulfur, nitrogen, Conradson carbon and asphaltenes, to convert them into lighter products, which can be valorized as fuels, for example to produce gasoline or diesel, or as raw materials for petrochemicals. The inventors have shown that, surprisingly, it was possible to incorporate a fraction of waste plastics, in various ways, into a heavy hydrocarbon feedstock traditionally treated in a bubbling bed or hybrid bubbling-entrained hydroconversion process, without significantly deteriorating the overall conversion of the feedstock. The present invention thus proposes a hydroconversion process for a heavy hydrocarbon feedstock in a bubbling or hybrid bubbling-entrained bed, said feedstock including a fraction of plastics derived from waste, thereby enabling the production of fuel base and other valuable hydrocarbons (light hydrocarbons, distillates for use in a steam cracker, particularly for the production of recycled polyolefins, base for the production of bitumen, lubricants, etc.) while ensuring the recovery of plastic waste that might otherwise be destined for landfill or incineration. More generally, the invention contributes to increasing the recycling rate of plastic waste while treating plastic impurities. Thus, in order to achieve at least one of the aforementioned objectives, among others, the present invention proposes, according to a first aspect, a hydroconversion process for a charge comprising the following successive steps: (a) the conditioning and introduction of said feed into a first hydroconversion section comprising at least one first bubbling bed or hybrid bubbling-entrained bed hydroconversion reactor comprising a first porous supported hydroconversion catalyst, said feed comprising between 1% and 50% by weight of a plastic fraction and 50% and 99% by weight of a heavy hydrocarbon fraction containing at least 50% by weight of a portion having a boiling point of at least 300°C, and containing sulfur and nitrogen; (b) a first hydroconversion step of said feed in the presence of hydrogen in said first hydroconversion section to obtain a first hydroconverted effluent; (c) optionally, a step of separating some or all of said first effluent resulting from step (b), to form at least a heavy cut boiling predominantly at a temperature greater than or equal to 350°C; (d) optionally, a second hydroconversion step in a second hydroconversion section comprising at least one second boiling bed or hybrid boiling-driven bed hydroconversion reactor of some or all of said first effluent resulting from step (b) or optionally of said heavy cut from step (c), said second hydroconversion reactor comprising a second porous supported catalyst operating in the presence of hydrogen, to produce a second hydroconverted effluent; Step (b) and the optional step (d) are carried out at an absolute pressure between 2 MPa and 38 MPa, at a temperature between 300°C and 550°C, and at a spatial velocity of one hour relative to the volume of each reactor. hydroconversion time between 0.05 h and 10 h, and with a quantity of hydrogen between 50 Nm³ / m³ and 5000 Nm³ / m³, (e) a fractionation step of all or part of said first hydroconverted effluent from step (b) or of said second hydroconverted effluent from step (d), in a fractionation section, to produce at least one heavy liquid product which boils predominantly at a temperature greater than or equal to 350°C, said heavy liquid product containing a residual fraction which boils at a temperature greater than or equal to 540°C. According to one or more implementations of the invention, in step (a), the plastic fraction and the heavy hydrocarbon fraction of the feed are introduced mixed into said at least one first hydroconversion reactor of the first hydroconversion section. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is mixed with the heavy hydrocarbon fraction so as to form a suspension, said suspension being heated to a temperature above the melting temperature of said plastic fraction to form the feed introduced into the first hydroconversion reactor. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is first mixed with a plastic diluent to form a first suspension, then said first suspension is mixed with the heavy hydrocarbon fraction to form a second suspension, said second suspension being heated to a temperature above the melting point of said plastic fraction to form the feed introduced into the first hydroconversion reactor According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles ( ), preferably previously mixed with a plastic diluent to form a suspension, is heated to a temperature temperature above the melting temperature of said plastic fraction to form a molten plastic fraction, then said molten plastic fraction is mixed with the heavy hydrocarbon fraction so as to form the feed introduced into the first hydroconversion reactor. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is heated to a temperature above the melting temperature of said plastic fraction to form a molten plastic fraction, then said molten plastic fraction is mixed with a plastic diluent to form a dilute molten plastic fraction mixed with the heavy hydrocarbon fraction to form the feed introduced into the first hydroconversion reactor. According to one or more implementations of the invention, in step (a), the plastic fraction and the heavy hydrocarbon fraction of the feed are introduced separately into said at least one first hydroconversion reactor of the first hydroconversion section. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is sent into an extruder, preferably with a plastic diluent, in which it is progressively heated to a temperature above the melting temperature of said plastic fraction, and brought to the pressure of said first hydroconversion reactor during a conveying preferably for a period of less than 15 minutes, and said extruded plastic fraction is introduced into the first hydroconversion reactor. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is mixed with a plastic diluent in a mixing section and heated in a heating section to a temperature above the melting temperature of said plastic fraction, preferably between 60°C and 295°C, before its introduction into the first hydroconversion reactor, the heating step being able to be carried out before or after mixing with the plastic diluent, and preferably after mixing with the plastic diluent. According to one or more embodiments of the invention, in step (a), the plastic fraction in the form of solid particles is first sent into a mixer to be mixed with a plastic diluent and to form a suspension, preferably at a temperature greater than or equal to ambient temperature and less than the melting temperature of said plastic fraction, and said plastic fraction in the form of a suspension is introduced into the first hydroconversion reactor. According to one or more implementations of the invention, in step (a), the fraction plastic in the form of solid particles is pre-mixed with a plastic diluent and with the first supported porous hydroconversion catalyst in a distribution and mixing box to form a suspension, then said suspension is introduced into the first hydroconversion reactor via the catalyst injection means in the first hydroconversion reactor. According to one or more embodiments of the invention, the charge comprises between 5% and 30% by weight, preferably between 5% and 20% by weight, of said plastic fraction, and between 70% and 95% by weight, preferably between 80% and 95% by weight, of said heavy hydrocarbon fraction. According to one or more embodiments of the invention, the process includes the separation step (c) separating part, or all, of the first hydroconverted effluent () from step (b) to produce at least the heavy cut boiling predominantly at a temperature greater than or equal to 350°C, and includes the second hydroconversion step (d) of said heavy cut. According to one or more implementations of the invention, the first hydroconversion section reactor(s) in step (b), and optionally in hydroconversion step (d), are bubbling-entrained hybrid bed reactors, said process further comprising a step of introducing a catalyst precursor, preferably molybdenum 2-ethylhexanoate, before injecting said feed into said at least one first bubbling-entrained hybrid bed reactor of the first hydroconversion section, such that a colloidal or molecular catalyst, preferably comprising molybdenum disulfide, is formed when said feed reacts with sulfur. According to one or more embodiments of the invention, the first hydroconversion catalyst, and optionally the second hydroconversion catalyst, contains at least one non-noble group VIII metal selected from nickel and cobalt, preferably nickel, and at least one group VIB metal selected from molybdenum and tungsten, preferably molybdenum, and comprising an amorphous support, preferably alumina. According to one or more embodiments of the invention, the heavy hydrocarbon fraction of the feed comprises, and may consist of, at least one of the following feeds, alone or in mixture: crude oil, topped-off crude oil, atmospheric residue or vacuum residue from atmospheric or vacuum distillation of crude oil (preferably from primary fractionation of crude oil), atmospheric residue or vacuum residue from atmospheric or vacuum distillation obtained during a direct coal liquefaction process, and preferably is vacuum residue from vacuum distillation of crude oil (preferably from primary fractionation of crude oil). According to one or more embodiments of the invention, the heavy hydrocarbon fraction of the feed comprises sulfur at a content greater than 0.5% by weight and nitrogen at a content between 1 ppm and 8000 ppm by weight, and preferably a Conradson carbon content of at least 3% by weight, and / or an asphaltene C content of at least 1% by weight, and / or a metal content of at least 20 ppm by weight. According to one or more embodiments of the invention, the plastic fraction of the filler comprises one or more polymers chosen from the list consisting of alkene polymers, diene polymers, vinyl polymers, styrenic polymers. According to one or more embodiments of the invention, the plastic fraction of the filler comprises at least 50% by weight, preferably at least 80% by weight, preferably at least 90% by weight, and most preferably at least 94% by weight, of polyolefins relative to the total weight of the plastic fraction of the filler. According to one or more embodiments of the invention, the polyolefins of the plastic fraction of the filler are chosen from the list consisting of polyethylene (PE), polypropylene (PP) and / or copolymers of ethylene and propylene. According to one or more embodiments of the invention, the plastic diluent is a hydrocarbon or a mixture of liquid hydrocarbons, and preferably the plastic diluent is a hydrocarbon oil composed of hydrocarbons of which at least 50% by weight, relative to the total weight of the hydrocarbon oil, have a boiling point between 180°C and 540°C, preferably selected from the list consisting of a vacuum gas oil (VGO), a settling oil or a recycling oil such as a fluidized bed catalytic cracking effluent FCC as a heavy recycling oil (HCO) or a light recycling oil (LCO), a pyrolysis oil from a hydrocracker, a light gas oil, an atmospheric residue, a vacuum residue, a deasphalted oil, and a resin, and more preferably the plastic diluent is an LCO, an HCO or a VGO. According to one or more embodiments of the invention, the plastic thinner is a hydrocarbon or a mixture of liquid hydrocarbons comprising, e.g., being made up of xylene, toluene, gasoline, or mixtures thereof. Other objects and advantages of the invention will become apparent from the following description of particular embodiments of the invention, given by way of non-limiting examples, the description being made with reference to the attached figures described below. List of figures Figures 1A to 1D illustrate the first embodiment of the hydroconversion process according to the invention, in which the heavy fraction and the fraction The plastic components of the feedstock are injected separately into the hydroconversion reactor, Le, without being mixed before their introduction into the hydroconversion reactor. This first embodiment will be referred to as direct injection. Figures 2A to 2E illustrate the second embodiment of the hydroconversion process according to the invention, in which the heavy fraction and the plastic fraction of the feedstock are mixed before being introduced into the hydroconversion reactor. This second embodiment will be referred to as indirect injection. [Fig.1A] Fig. 1A is a functional diagram illustrating a first variant of the first embodiment of the hydroconversion process according to the invention, in which the plastic fraction is heated before being introduced, in substantially liquid form, into the hydroconversion reactor. [Fig.1B] Fig. 1B is a functional diagram illustrating a second variant of the first embodiment of the hydroconversion process according to the invention, in which the plastic fraction is mixed with a diluent and then heated to be injected in substantially liquid form into the hydroconversion reactor. [Fig.1C] Fig. 1C is a functional diagram illustrating a third variant of the first embodiment of the hydroconversion process according to the invention, in which the plastic fraction is injected into the hydroconversion reactor in the form of a suspension. [Fig.1D] Fig. 1D is a functional diagram illustrating a fourth variant of the first embodiment of the hydroconversion process according to the invention, in which the plastic fraction is injected into the hydroconversion reactor as a suspension via the injection means of the supported catalyst. [Fig.2A] Fig. 2A is a functional diagram illustrating a first variant of the second embodiment of the hydroconversion process according to the invention, in which the plastic fraction is mixed in solid form with the heavy fraction. [Fig.2B] Fig. 2B is a functional diagram illustrating a second variant of the second embodiment of the hydroconversion process according to the invention, in which the plastic fraction is mixed in solid form with a diluent and then mixed with the heavy fraction. [Fig.2C] Figure 2C is a functional diagram illustrating a third variant of the second embodiment of the hydroconversion process according to the invention, in which the plastic fraction is heated so as to be in a substantially liquid form before being mixed with the heavy fraction. [Fig.2D] Figure 2D is a functional diagram illustrating a fourth variant of the second embodiment of the hydroconversion process according to the invention, in which the plastic fraction is mixed in solid form with a diluent and then heated so as to be in substantially liquid form before being mixed with the heavy fraction. [Fig.2E] Figure 2E is a functional diagram illustrating a fifth variant of the second embodiment of the hydroconversion process according to the invention, in which the plastic fraction is heated so as to be in a substantially liquid form, then mixed with a diluent before being mixed with the heavy fraction. In the figures, the same references designate identical or analogous elements. Description of the implementation methods Embodiments of the process according to the invention will now be described in detail. In the following detailed description, numerous specific details are presented to provide a more thorough understanding of the process. However, it will be apparent to those skilled in the art that the process can be implemented without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description. Some definitions are given below for a better understanding of the invention. In this description, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended, not excluding other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist." In this description, the expression "between … and …" means that the limit values ​​of the interval are included in the range of values ​​described, unless otherwise specified. In the present invention, the different ranges of values ​​for given parameters can be used alone or in combination. For example, a preferred range of pressure values ​​can be combined with a more preferred range of temperature values, or a preferred range of values ​​for one chemical compound or element can be combined with a more preferred range of values ​​for another compound or element. chemical. In this description, a mixture of substances in suspension, also called a slurry, typically refers to a system of solid particles dispersed in a liquid (liquid dispersion). More specifically, a plastic fraction of the slurry corresponds to a system containing solid plastic particles dispersed in a liquid, for example, a system containing between 1% and 50% by weight of solid plastic particles dispersed in a liquid, or even between 1% and 30% by weight, or between 5% and 20% by weight. The continuous liquid phase in which the solid plastic particles are dispersed can be a diluent and / or the heavy liquid fraction of the slurry. As defined, it does not include the polymer(s) of the plastic fraction that would be melted. The term "hydroconversion" refers to a process whose primary purpose is to reduce the boiling point range of a feed containing at least 50% of a heavy hydrocarbon fraction, and in which a substantial portion of the feed is converted into products with lower boiling point ranges than the original feed. Hydroconversion generally involves the fragmentation of larger hydrocarbon molecules into smaller molecular fragments with fewer carbon atoms and a higher hydrogen-to-carbon ratio. The reactions carried out during hydroconversion reduce the size of hydrocarbon molecules, primarily by breaking carbon-carbon bonds, in the presence of hydrogen to saturate the broken bonds and aromatic rings.The mechanism by which hydroconversion occurs typically involves the formation of hydrocarbon free radicals during fragmentation, primarily by thermal cracking, followed by the capping of the free radical terminations or fragments with hydrogen in the presence of active catalyst sites. Of course, during a hydroconversion process, other reactions typically associated with hydrotreating can occur, such as, among others, the removal of sulfur or nitrogen from the feedstock, or the saturation of olefins, as more broadly defined below. The term "hydrotreating," commonly referred to as "HDT," refers to a gentler operation whose main purpose is to remove impurities such as sulfur, nitrogen, oxygen, halides, and trace metals from the feedstock, and to saturate olefins and / or stabilize hydrocarbon free radicals by causing them to react with hydrogen rather than allowing them to react with themselves. The primary goal is not to change the boiling point range of the feedstock. Thus, hydrotreating includes, among other things, hydrodesulfurization reactions (commonly called "HDS") and hydrodeazotation reactions (commonly called "HDN") and hydrodemetallation reactions (commonly called "HDM"), accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydrodeasphalting, and Conradson carbon reduction are among the processes involved. Hydrotreating is most often carried out using a fixed-bed reactor, although other reactors can also be used for hydrotreating, for example, a bubbling-bed hydrotreating reactor. The term "hydroconversion reactor" refers to any vessel in which the hydroconversion of a feedstock is the primary objective, e.g., the cracking of the feedstock (i.e., the reduction of its boiling point range), in the presence of hydrogen and a hydroconversion catalyst. Hydroconversion reactors typically include at least one inlet port through which the feedstock and hydrogen can be introduced and an outlet port from which valuable material can be withdrawn. Specifically, hydroconversion reactors are also characterized by having sufficient thermal energy to cause the fragmentation of larger hydrocarbon molecules into smaller molecules through thermal decomposition. Examples of reactors Hydroconversion reactors include, but are not limited to, driven bed reactors, also known as slurry reactors (three-phase reactors — liquid, gas, solid — in which the solid and liquid phases can behave as a homogeneous phase), bubbling bed reactors (three-phase fluidized reactors), moving bed reactors (three-phase reactors with downward movement of the solid catalyst and upward or downward flow of liquid and gas), and fixed bed reactors (three-phase reactors with downward flow of liquid charge over a fixed bed of catalyst supported with hydrogen typically flowing simultaneously with the liquid, but possibly counter-currently in some cases). The terms "hybrid bed," "hybrid bubbling bed," and "hybrid bubbling-driven bed" for a hydroconversion reactor refer to a bubbling bed hydroconversion reactor that includes a driven catalyst in addition to the porous supported catalyst maintained within the bubbling bed reactor. Similarly, for a hydroconversion process, these terms refer to a process that combines the operation of a bubbling bed and a driven bed in at least one hydroconversion reactor. The hybrid bed is a mixed bed of two types of catalysts with necessarily different particle sizes and / or densities. One type of catalyst—the "porous supported catalyst"—is maintained within the reactor, and the other type—the "driven catalyst," also commonly called a "slurry catalyst"—is driven out of the reactor. with the effluents (recovered feedstock). In the present invention, the entrained catalyst is a colloidal catalyst or a molecular catalyst, as defined below. The terms "colloidal catalyst" and "colloidally dispersed catalyst" refer to catalyst particles having a colloidal particle size, e.g., less than 1 µm in size (diameter), preferably less than 500 nm in size, more preferably less than 250 nm in size, or less than 100 nm in size, or less than 50 nm in size, or less than 25 nm in size, or less than 10 nm in size, or less than 5 nm in size. The term "colloidal catalyst" includes, but is not limited to, molecularly or molecularly dispersed catalyst compounds. The terms "molecular catalyst" and "molecularly dispersed catalyst" refer to catalyst compounds that are essentially "dissolved" or completely dissociated from other catalyst compounds or molecules in a feed, non-volatile liquid fraction, background fraction, residues, or other feed or product in which the catalyst may be found. They also refer to very small catalyst particles or sheets that contain only a few catalyst molecules joined together (e.g., 15 molecules or fewer). The terms "porous supported catalyst," "solid supported catalyst," and "supported catalyst" refer to catalysts typically used in conventional bubbling-bed and fixed-bed hydroconversion systems, including catalysts designed primarily for hydrocracking or hydrodemetallation and catalysts designed primarily for hydrotreating. Such catalysts typically comprise (i) a catalyst support with a large surface area and numerous interconnected channels or pores, and (ii) fine particles of an active catalyst, such as cobalt, nickel, tungsten, molybdenum sulfides, or mixed sulfides of these elements (e.g., NiMo, CoMo, etc.), dispersed within the pores. Supported catalysts are commonly produced as cylindrical extrudates ("pellets") or spherical solids, although other shapes are possible. The process according to the invention and its operation are described in more detail below, with reference to figures 1 A to 2 E representing different variants of the process according to the invention. In all the illustrated variants, certain steps of the hydroconversion process are similar. The sections of the hydroconversion plant implementing these similar steps are designated by the same reference in the figures, such as the hydroconversion section 20, the fractionation section 30 and the subsequent treatment(s) 40 described below. The object of the invention is to propose a method for the hydroconversion of a charge comprising between 1% and 50% by weight of a plastic fraction and 50% and 99% by weight of a heavy hydrocarbon fraction containing a portion of at least 50% by weight having a boiling point of at least 300°C, and containing sulfur, metals, and nitrogen, or even metals, Conradson carbon and asphaltenes, comprising the following successive stages: (a) conditioning and introduction of the feed into a first hydroconversion section 20 comprising at least a first bubbling bed or hybrid bed reactor comprising a first porous supported hydroconversion catalyst; (b) a first hydroconversion step of said feed in the presence of hydrogen in said first hydroconversion section 20 to obtain a first hydroconverted effluent 105; (c) optionally, a step of separating some or all of said first effluent resulting from step (b), to recover at least a heavy cut boiling predominantly at a temperature greater than or equal to 350°C; (d) optionally, a second hydroconversion step in a second hydroconversion section (not shown in the figures) comprising at least a second bubbling bed or hybrid bed reactor of some or all of said first effluent resulting from step (b) or optionally of said heavy cut from step (c), said second reactor comprising a second porous supported catalyst operating in the presence of hydrogen, to produce a second hydroconverted effluent; step (b) and optional step (d) being implemented at an absolute pressure between 2 MPa and 38 MPa, at a temperature between 300°C and 550°C, at an hourly space velocity relative to the volume of each reactor between 0.05 h₁₂₋₁₀ and 10 h₁₋₁₀, and with a quantity of hydrogen between 50 Nm₁₀ / m³ and 5000 Nm₁₀m³, (e) a fractionation step of all or part of said first hydroconverted effluent 105 from step (b) or of said second hydroconverted effluent from step (d), in a fractionation section (30), to produce at least one heavy product which boils predominantly at a temperature greater than or equal to 350°C, said heavy product containing a residual fraction which boils at a temperature greater than or equal to 540°C. The charge According to a key aspect of the invention, the filler comprises a plastic fraction and a heavy hydrocarbon fraction. The plastic fraction constitutes between 1% and 50% of the load weight (total load weight), preferably between 5% and 30% of the load weight, and more preferably between 5% and 20% of the load weight. The heavy hydrocarbon fraction containing at least 50% by weight of a portion having a boiling point of at least 300°C, and containing sulfur, Conradson carbon, metals, nitrogen, and asphaltenes, constitutes between 50% and 95% by weight of the charge, preferably between 70% and 95% by weight of the charge, and more preferably between 80% and 95% by weight of the charge. The plastic fraction of the feedstock in the process according to the invention comprises plastics which themselves more particularly comprise polymers. Thus, the plastic fraction is understood to be a solid fraction of plastics comprising one or more polymers, and which may contain other compounds, such as additives of organic or inorganic origin and / or impurities resulting from use, particularly those arising from the life cycle of plastic materials and objects, and / or from the waste collection and sorting process. For example, impurities resulting from use may be metallic, organic, or mineral; they may include packaging residues, food waste, or compostable residues (biomass).Usage impurities may also include glass, wood, cardboard, paper, aluminum, iron, metals, tires, rubber, silicones, rigid polymers, thermosetting polymers, household, chemical or cosmetic products, used oils, water. In this description, "plastic impurities" refers to all compounds in the plastic fraction that are not polymers and that are not likely to be converted during the hydroconversion step(s) of the process. For example, some organic additives can be at least partially converted during hydroconversion, just like polymers. These are therefore not considered plastic impurities. Conversely, some inorganic additives can be removed during hydroconversion, for example, those containing metals, and / or sulfur, and / or nitrogen, and / or oxygen, and / or other heteroatoms (Cl, Br, etc.). These are considered plastic impurities. The plastics included in the plastic fraction of the feedstock in the process according to the invention are generally production by-products and / or waste, including household waste, construction waste, or waste electrical and electronic equipment. Preferably, the plastic waste comes from collection and sorting channels. Plastics or plastic materials are generally polymers that are most often mixed with additives to form, after shaping, various materials and objects (injection-molded parts, tubes, films, fibers, fabrics, sealants, coatings, etc.). The additives used in plastics can be organic or inorganic compounds. Examples include fillers, colorants, pigments, plasticizers, and modifiers. properties, combustion retardant, etc. The plastic fraction of the feedstock in the process according to the invention therefore comprises polymers, and in particular thermoplastics. The polymers included in the plastic fraction of the feedstock can be alkene polymers, diene polymers, vinyl polymers, styrenic polymers (e.g., polystyrene "PS"), polyesters, and / or polyamides. Preferably, the polymers included in the plastic fraction of the feedstock are alkene polymers, diene polymers, vinyl polymers, and / or styrenic polymers (e.g., polystyrene "PS"). Preferably, the polymers included in the plastic feedstock are polyolefins, such as polyethylene (PE), polypropylene (PP), and / or ethylene-propylene copolymers.For example, the plastic fraction of the filler comprises at least 50% by weight, preferably at least 80% by weight, preferably at least 90% by weight, and most preferably at least 94% by weight, of polyolefins relative to the total weight of the plastic fraction of the filler. The plastic fraction of the feedstock may include polymer blends, in particular blends of thermoplastics and / or blends of thermoplastics and other polymers, and compounds other than these thermoplastics and polymers, including additives advantageously used to formulate the plastic material and generally impurities resulting from the life cycle of plastic materials and articles, and / or from the waste collection and sorting process. The plastic fraction of the feedstock in the process according to the invention generally comprises less than 50% by weight of these additives and impurities, preferably less than 20% by weight, and preferably less than 10% by weight. The plastic fraction of the feedstock can advantageously be pretreated upstream of the process so as to at least eliminate all or part of the so-called coarse impurities, that is, impurities in the form of particles 10 mm or larger, preferably 5 mm or larger, or even 1 mm or larger, for example, impurities of the type wood, paper, biomass, iron, aluminum, glass, etc., and to shape it generally into particles (divided solids) so as to facilitate processing in the process. This pretreatment may include a grinding step, an atmospheric pressure washing step, and / or a drying step. This pretreatment may be carried out at a different site, for example, at a waste collection and sorting center, or at the same site where the treatment process according to the invention is implemented.Preferably, this pretreatment reduces the content of impurities to less than 6% by weight. Following pretreatment, the feedstock is generally stored in granular form, for example as ground material or powder, to facilitate handling and transport to the process. The heavy hydrocarbon fraction of the feed in the process according to the invention is a heavy hydrocarbon fraction containing a portion of at least 50% having a boiling point of at least 300°C, preferably of at least 350°C, and even more preferably of at least 375°C. This heavy hydrocarbon fraction of the feedstock can be crude oil, or come from the refining of crude oil or the processing of another hydrocarbon source in a refinery. Preferably, the heavy hydrocarbon fraction of the feedstock is crude oil, topped-off crude oil, or consists of atmospheric residues and / or vacuum residues from atmospheric and / or vacuum distillation of crude oil. The heavy hydrocarbon fraction of the feedstock may also consist of atmospheric and / or vacuum residues from atmospheric and / or vacuum distillation of effluents from thermal conversion, hydrotreating, hydrocracking and / or hydroconversion units. Preferably, the heavy hydrocarbon fraction of the feedstock consists of vacuum residues. These vacuum residues generally contain a portion of at least 50% with a boiling point of at least 450°C, and most often at least 500°C, or even at least 540°C. The vacuum residues can come directly from crude oil or from other refining units, such as, among others, tailings hydrotreating, tailings hydrocracking, and tailings visbreaking. Preferably, the vacuum residues are vacuum residues from the vacuum distillation column of primary crude fractionation (known as "straight run," or "SR" for short). The heavy hydrocarbon fraction of the feedstock may still consist of vacuum distillates, either directly from crude oil or from cuts from other refining units, such as, among others, cracking units, like FCC (Fluid Catalytic Cracking) and hydrocracking, and thermal conversion units, like coking units or visbreaking units. The heavy hydrocarbon fraction of the feed can also consist of aromatic cuts extracted from a lubricant production unit, deasphalted oils from a deasphalting unit also called DAO (deasphalting unit raffinates), asphalts from a deasphalting unit (deasphalting unit residues). The heavy hydrocarbon fraction of the feedstock can also be a residual fraction from the direct liquefaction of coal (an atmospheric residue and / or a vacuum residue from, for example, the H-Coal™ process), a vacuum distillate from the direct liquefaction of coal, such as the H-Coal™ process, or even a residual fraction resulting from the direct liquefaction of lignocellulosic biomass alone or mixed with coal and / or a petroleum fraction. All these fractions can be used to constitute the heavy hydrocarbon fraction of the feed treated according to the invention, alone or in mixture. According to one or more implementations, the heavy hydrocarbon fraction comprises, and may consist of, at least one of the following feedstocks, alone or in mixture: crude oil, topped-off crude oil, atmospheric residue or vacuum residue from atmospheric or vacuum distillation of crude oil (preferably from primary fractionation of crude oil), atmospheric residue or vacuum residue from atmospheric or vacuum distillation obtained during a direct coal liquefaction process, and preferably is vacuum residue from vacuum distillation of crude oil (preferably from primary fractionation of crude oil). The heavy hydrocarbon fraction of the feed treated according to the invention contains impurities, such as sulfur and nitrogen. It may also contain impurities such as metals, Conradson carbon and asphaltenes, in particular C-asphaltenes, which are insoluble in heptane. Metal content may be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 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 is usually 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 C7 asphaltene content (heptane-insoluble compounds according to ASTM D 6560, which also corresponds to NF T60-115) is at least 1% by weight and is often greater than or equal to 3% by weight. C7 asphaltenes are known to inhibit the conversion of residual cuttings, both through their ability to form heavy hydrocarbon residues, commonly called coke, and through their tendency to produce sediments that severely limit the operability of hydrotreating and hydroconversion units. The Conradson carbon content can be greater than or equal to 3% by weight, or even at least 5% by weight. The Conradson carbon content is defined by ASTM D 482 and represents, for those skilled in the art, a well-known assessment of the amount of carbon residue produced after pyrolysis under standard temperature and pressure conditions. These contents are expressed as a percentage by weight of the total weight of the heavy hydrocarbon fraction of the load. (a) Conditioning and injection stage of the feed into the first hydroconversion reactor The process according to the invention includes a step (a) of conditioning and introducing the feed into a first hydroconversion section 20 comprising at least a first bubbling bed or hybrid bed reactor comprising a first porous supported hydroconversion catalyst. By conditioning the feed, we mean preparing it for the subsequent step (b) of hydroconversion of the feed once it has been introduced into the first hydroconversion reactor; that is, bringing it to a state and temperature and pressure conditions suitable for hydroconversion in the first reactor. hydroconversion. The plastic fraction of the feed can be introduced in suspension into the first hydroconversion reactor, or in an essentially liquid form, previously mixed or not with the heavy hydrocarbon fraction of the feed. The term "plastic fraction in substantially liquid form" means that at least 80% by weight of the polymer(s) in the plastic fraction are in liquid form, preferably at least 90% by weight, more preferably at least 95% by weight, and even more preferably at least 98% by weight. Polymers in the plastic fraction in liquid form are defined as polymers that are not in solid form, the latter generally being considered to correspond to the crystalline, semi-crystalline, and amorphous states of a polymer. The plastic fraction, in the form of solid particles or in an essentially liquid form, is preferably mixed with a diluent before being introduced into the first hydroconversion reactor, and where appropriate before being mixed with the heavy hydrocarbon fraction of the feedstock. This diluent, referred to as the "plastic diluent" in this description and referenced as 107 in the figures, consists of a liquid hydrocarbon or a mixture of liquid hydrocarbons. For example, the plastic diluent is a hydrocarbon oil composed of hydrocarbons of which at least 50% by weight, relative to the total weight of the hydrocarbon oil, have a boiling point between 180°C and 540°C.Examples of suitable hydrocarbon diluents include, but are not limited to, vacuum gas oil known as "VGO" (which typically has a boiling range of 360°C to 524°C), settling oil or recycling oil (which typically has a boiling range of 360°C to 550°C), for example, fluidized bed catalytic cracking (FCC) effluent such as heavy cycle oil (HCO) or light cycle oil (LCO), pyrolysis oil from a hydrocracker, light gas oil (which typically has a boiling range of 200°C to 360°C), atmospheric residues, etc. Vacuum residues (which typically have a boiling range of 524°C or higher), deasphalted oils, and resins. The plastic diluent may also include, e.g., be composed of, lighter liquid hydrocarbons (typically C5+ hydrocarbons, i.e., hydrocarbons that can have S and more than 5 carbon atoms per molecule), for example, xylene, toluene, gasoline, mixtures thereof, etc. Depending on one or more embodiments, the plastic diluent is an LCO, an HCO, or a VGO. The plastic diluent 107 may act as a solvent for the plastic fraction, in particular for the polymer(s) of the plastic fraction. Different implementations of step (a) are possible, which are distinguished at a first level by the way in which the feedstock is introduced into the first hydroconversion reactor: According to a first embodiment of the invention, referred to as "direct injection" in this description, the plastic fraction and the heavy hydrocarbon fraction are injected separately into the first hydroconversion reactor (i.e., without being mixed before their introduction into the hydroconversion reactor). This first embodiment notably limits the risk of incompatibility between the heavy hydrocarbon and plastic fractions of the feedstock, which could cause demixing or precipitation of asphaltenes, for example. According to this first embodiment, different variations can be implemented and are described in more detail below with reference to Figures 1A, 1B, 1C, and 1D. These variations are distinguished, at a second level, by the fact that the plastic fraction is introduced into the hydroconversion reactor in a predominantly liquid form (Figures 1A and 1B) or as a slurry (Figures 1C and 1D). - According to a second embodiment of the invention, referred to as "indirect injection" in this description, the plastic fraction and the heavy hydrocarbon fraction are mixed before being introduced into the hydroconversion reactor. This second embodiment has the advantage of improved dispersion / solubilization of the plastic fraction within the feedstock, and such a more homogeneous feedstock introduced into the reactor is, for example, conducive to good fluidization of the catalyst and to the overall good hydrodynamic operation of the reactor. It can also allow the use of common equipment, such as furnaces, feedstock distributors, and hydrogen mixers with the feedstock, for example, of the T-mixer type, which can help reduce investment costs.Here again, according to this second embodiment, different variants can be implemented, described below in relation to figures 2A, 2B, 2C, 2D, and 2E. These variants are distinguished at a second level by the fact that the plastic fraction is in solid or slurry form (figures 2A and 2B), or alter-. natively in essentially liquid form (figures 2C, 2D and 2E) when mixed with the heavy hydrocarbon fraction. In the figures, bold arrows represent a flow in which the plastic fraction is in substantially liquid form (i.e. at least 90% by weight, preferably at least 95% by weight, and more preferably at least 98% by weight of the plastic fraction is in liquid form), and grey rectangles represent devices in which the plastic fraction is heated so as to melt. Direct injection: fractions injected separately into the hydroconversion reactor. Step (a1) Figure 1A illustrates a first variant of the first embodiment, in which the step (a) of conditioning and injecting the charge is a step (al) of extruding the plastic fraction and introducing said extruded plastic fraction into the first hydroconversion reactor of the first hydroconversion section 20. The plastic fraction is thus introduced into said reactor in a substantially liquid form. The associated steps and devices other than step (a) of [Fig.1 A] are described later in the description. Extrusion is a process that allows the injection or shaping of a polymer that is initially in a solid state. In an extrusion process, the material is conveyed via one or more screws, mixed, and heated, which melts it. Simultaneously, the screw(s) convey the material and increase its pressure, allowing it to be injected into a die or mold. According to this first variant of the first embodiment of the invention, the extrusion of the plastic fraction is a means of introducing the plastic fraction, which is solid at room temperature, into the hydroconversion reactor operating under high pressure and temperature. Extrusion thus makes it possible to heat, in order to liquefy, and pressurize the plastic fraction under the operating conditions of the first hydroconversion reactor as operated in step (b). The material is not injected into a die or mold as in a conventional extrusion process, thus not constituting a shaping process, but is injected directly into the first hydroconversion reactor of the first hydroconversion section 20. According to this first variant of the first embodiment of the invention, the plastic fraction in the form of solid particles 102 is sent into an extruder 10, preferably with a plastic diluent 107 as described above, in which it is progressively heated to a temperature above the melting temperature of said plastic fraction, and pressurized by said first hydroconversion reactor during conveying, preferably for a duration in- less than 15 minutes, and the plastic fraction thus extruded 103 is introduced into the first hydroconversion reactor of the first hydroconversion section 20. During extrusion, the plastic fraction is preferably gradually heated to a temperature above its melting point so as to melt it. Advantageously, at least 80% by weight of the plastic fraction is in liquid (molten) form after extrusion, very advantageously at least 90% by weight, preferably at least 95% by weight, or even 98% by weight. As described above, the plastic fraction generally contains compounds other than polymers, notably plastic impurities. Some of these non-polymer compounds, including plastic impurities, may be insoluble and / or have a higher melting point than the polymer(s) in the plastic fraction. Even if all of the polymer(s) melt, a portion of the liquid fraction, taking into account the non-polymer compounds, may therefore remain in solid form.This is true for all the stages described below in which heating results in the total or almost total decomposition of the plastic fraction. The extrusion temperature depends on the polymer composition of the plastic fraction (nature and proportion(s) of the polymer(s)). It can also depend on a plastic diluent 107 added to the plastic fraction during extrusion. Preferably, the extruder 10 is operated at a temperature between a temperature 25°C below the melting temperature of the plastic fraction and a temperature 25°C above the melting temperature of the plastic fraction. In the case where the plastic fraction comprises a mixture of polymers, the extruder 10 is operated at a temperature between a temperature 25°C lower than the melting temperature of the least refractory polymer (i.e. which has the lowest melting temperature) of the plastic fraction and a temperature 25°C higher than the melting temperature of the most refractory polymer (i.e. which has the highest melting temperature) of the plastic fraction. Advantageously, the plastic fraction is preferably gradually heated in the extruder 10 to a temperature above the melting temperature of the polymer with the highest melting point. As an indication, the melting temperature of polypropylene (PP) is approximately 170°C, the melting temperature of polyethylene (PE) is between approximately 85°C and 140°C, and the melting temperature of polystyrene is between approximately 240°C and 270°C. The extrusion temperature is preferably such that it limits the thermal degradation of the polymer(s) that could lead to the formation of undesirable solids. For example, the extrusion temperature is advantageously below 200°C, particularly when the plastic fraction consists mainly of PE. It can advantageously be less than 300°C in the case where the plastic fraction mainly comprises PS. Preferably, the extruder 10 is operated at a temperature between 60°C and 295°C, more preferably between 60° and 195°C. Advantageously, the extruder 10 is operated at a temperature between 60°C and 165°C, so as to melt a plastic fraction consisting mainly of PE as a polymer. Advantageously, the extruder 10 is operated at a temperature between 145°C and 195°C, so as to melt a plastic fraction consisting mainly of PP as a polymer. Advantageously, the extruder 10 is operated at a temperature between 215°C and 295°C, so as to melt a plastic fraction consisting mainly of PS as a polymer. The operating temperature of the extruder is advantageously adapted according to the composition of the plastic fraction. Advantageously, the extruder 10 includes at least one screw conveying section, called the extrusion section, fed by the plastic fraction. The residence time in this extrusion section (volume of said section divided by the volumetric flow rate of plastic fraction) is advantageously less than 15 minutes, preferably less than 10 minutes, and preferably less than 2 minutes. The said extrusion section is advantageously connected to a vacuum extraction system in order to remove impurities such as dissolved gases, light organic compounds and / or moisture that may be present in the plastic fraction. The extrusion section may also advantageously include a filtration system to remove undesirable solid particles, for example, those larger than 200 µm, and preferably larger than 40 µm, such as sand particles. If a diluent is used, the viscosity can decrease, making it possible to filter out smaller particles, for example, those larger than 3 µm. The plastic fraction is advantageously brought into contact with a hydrocarbon plastic diluent 107, obtained from the hydroconversion process according to the invention or not, and preferably obtained from the hydroconversion process, within said extrusion section of the extruder 10. The use of a plastic thinner offers the following advantages: - reduce the viscosity of the plastic fraction, which makes it easier to transport the diluted plastic fraction over longer distances; - reduce the operating temperature of the extruder 10, and possibly limit the thermal degradation of the polymer(s) in the plastic fraction. For example, it is possible to extrude, at least after the point(s) of contact with the plastic diluent 107, from a temperature lower than 25°C below the melting temperature of the plastic fraction; - to initiate the dispersion of the polymer(s) of the plastic fraction in a low-viscosity phase so that it / they mix more easily with the heavy hydrocarbon fraction within the first hydroconversion reactor of the first hydroconversion section 20. Separately to the introduction of the extruded plastic fraction, diluted or not, the heavy hydrocarbon fraction 101 is introduced into the first hydroconversion reactor, and the hydroconversion step (b) as described later is carried out. Prior to its introduction into the first hydroconversion reactor, the heavy hydrocarbon fraction 101 can be mixed with an entrained catalyst precursor 104, so that, during the formation of the entrained catalyst, in particular by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. The entrained catalyst precursor can be chosen from among all metallic catalyst precursors known to a person skilled in the art, capable of forming a colloidally or molecularly dispersed catalyst (i.e., the entrained catalyst) in the presence of hydrogen and / or H:S and / or any other sulfur source, and enabling hydroconversion of the feed after its injection into the first hydroconversion reactor. The catalyst precursor is advantageously an oil-soluble catalyst precursor containing at least one transition metal. The catalyst precursor preferably comprises an oil-soluble organometallic compound or complex. The catalyst precursor may comprise an oil-soluble organometallic or bimetallic compound or complex comprising one or two of the following metals: Mo, Ni, V, Fe, Co or W, or mixtures of such compounds / complexes. The oil-soluble catalyst precursor preferably has a decomposition temperature (temperature below which the catalyst precursor is substantially chemically stable) in a range of 100°C to 350°C, more preferably in a range of 150°C to 300°C, and most preferably in a range of 175°C to 250°C. The oil-soluble organometallic compound or complex is preferably chosen from the group consisting of molybdenum 2-ethylhexanoate, naphthanate molybdenum, vanadium naphthanate, vanadium octoate, molybdenum hexacarbonyl, vanadium hexacarbonyl, and iron pentacarbonyl are examples of oil-soluble catalyst precursors. More preferably, the catalyst precursor comprises molybdenum and, for example, includes a compound selected from the group consisting of molybdenum 2-ethylhexanoate, molybdenum naphthanate, and molybdenum hexacarbonyl. A currently preferred catalyst precursor comprises, or consists of, molybdenum 2-ethylhexanoate (also commonly called molybdenum octoate). Typically, molybdenum 2-ethylhexanoate contains 15% by weight of molybdenum and has a decomposition temperature or decomposition temperature range high enough to avoid substantial thermal decomposition when mixed with a heavy hydrocarbon fraction at a temperature below 250°C, A skilled professional can select a mixing temperature profile that results in the mixing of the chosen precursor, without substantial thermal decomposition prior to the formation of the colloidal or molecular catalyst. The catalyst precursor 104, preferably an oil-soluble catalyst precursor, can be premixed with a hydrocarbon stream of diluent to form a diluted precursor mixture, as described in documents US2005 / 0241991, US10822553 or US10941353 and recalled below. The catalyst precursor 104 can be premixed with a diluent to form a diluted precursor mixture, said premix being preferably carried out at a temperature below a temperature at which a substantial part of the catalyst precursor begins to decompose, preferably between ambient temperature, e.g. 15°C, and 300°C, more preferably between 15°C and 200°C, even more preferably between 50°C and 200°C, even more preferably between 75°C and 150°C, and even more preferably between 75°C and 100°C, and advantageously for a period of time from 1 second to 30 minutes. Typically, the catalyst precursor diluent can be a hydrocarbon oil composed of hydrocarbons of which at least 50% by weight, relative to the total weight of the hydrocarbon oil, have a boiling point between 180°C and 540°C. Examples of suitable hydrocarbon diluents for precursor dilution include, but are not limited to, vacuum gas oil known as "VGO" (which typically has a boiling range of 360°C to 524°C), settling oil or recycling oil (which typically has a boiling range of 360°C to 550°C), for example, fluidized bed catalytic cracking (FCC) effluent such as heavy cycle oil (HCO) or light cycle oil (LCO). Pyrolysis oil from a hydrocracker, light gas oil (which typically has a boiling range of 200°C to 360°C), atmospheric residues, vacuum residues (which typically have a boiling range of 524°C or higher), deasphalted oils, and resins. The catalyst precursor diluent is preferably atmospheric residue, vacuum residue, or VGO. The diluted precursor can then be mixed with the heavy hydrocarbon fraction 101, preferably at a temperature between ambient temperature, e.g., 15°C, and 300°C, and advantageously for a period of time from 1 second to 30 minutes, preferably from 1 second to 10 minutes, and even more preferably in a range of 2 seconds to 3 minutes. In this description, a mixing time (or residence time for the mixture) of 1 second includes instantaneous mixing.The mass ratio of catalyst precursor 104 to hydrocarbon oil diluent is preferably in a range of about 1:500 to about 1:1, more preferably in a range of about 1:150 to about 1:2, and even more preferably in a range of about 1:100 to about 1:5 (e.g. 1:100, 1:50, 1:30, or 1:10). Without mixing with a diluent, it is best to ensure that the components are mixed for a sufficient time to completely / thoroughly blend the catalyst precursor with the heavy hydrocarbon fraction before the formation of the entrained catalyst. However, a long mixing time, for example, 24 hours, can result in prohibitive costs for certain industrial operations. Premixing the catalyst precursor 104 with a hydrocarbon diluent greatly facilitates the complete and intimate mixing of the precursor in the heavy hydrocarbon fraction, particularly in the relatively short time period required for large-scale industrial operations to be economically viable. The dilute precursor is preferably combined with the heavy hydrocarbon fraction and mixed for a sufficient time to disperse the catalyst precursor throughout the heavy fraction so that the catalyst precursor is completely / intimately mixed with the heavy hydrocarbon fraction. To achieve sufficient mixing before the formation of the colloidal or molecular catalyst, the dilute precursor and the heavy fraction are most preferably mixed for a period of time in the range of 1 second to 10 minutes, and even more preferably in the range of 2 seconds to 3 minutes. Increasing the vigor and / or shear energy of the mixing process generally reduces the time required to achieve complete / intimate mixing. Examples of mixing apparatus that can be used to achieve complete / intimate mixing of the catalyst precursor 104 and the heavy hydrocarbon fraction 101 include, but are not limited to, high shear mixing such as mixing created in a pump with a propeller or turbine rotor, multiple static inline mixers, multiple static inline mixers in combination with high shear inline mixers, multiple static inline mixers in combination with high shear inline mixers, multiple static inline mixers in combination with high shear inline mixers followed by recirculation pumping into the buffer tank, combinations of the above devices followed by one or more multi-stage centrifugal pumps. The heavy hydrocarbon fraction 101 and the diluted precursor are preferably mixed and conditioned at a temperature in the range of 50°C to 200°C, more preferably in the range of 75°C to 175°C, before the introduction of the heavy hydrocarbon fraction into the first hydroconversion reactor. Preferably, the gauge pressure is between 0 MPa and 25 MPa, more preferably between 0.01 MPa and 5 MPa. The heavy hydrocarbon fraction 101, which may contain the entrained catalyst precursor, diluted or not, may be heated in at least one preheating device before being introduced into the hydroconversion reactor. This preheating can help achieve a target temperature in the first hydroconversion reactor in the subsequent step (b). Preheating is preferably carried out at a temperature between 280°C and 450°C, even more preferably between 300°C and 400°C, and even more preferably between 320°C and 365°C. This preheating may be carried out at a temperature that is 100°C lower, preferably 50°C lower, than the hydroconversion temperature in the hydroconversion reactor. The absolute pressure during this preheating can be between atmospheric pressure (e.g. 0.101325 MPa) and 38 MPa, preferably between 5 MPa and 25 MPa, and preferably between 6 MPa and 20 MPa.Preheating advantageously causes the release of sulfur contained in the heavy hydrocarbon fraction, which can combine with the metal of the catalyst precursor. The colloidal or molecular catalyst can form, or at least begin to form, in situ within the heavy hydrocarbon fraction during this preheating step. In order to form the colloidal or molecular catalyst, sulfur must be available (e.g., as H₂S) to combine with the metal of the dispersed catalyst precursor composition. The entrained catalyst can also form in step (b) of hydroconversion. In cases where the heavy hydrocarbon fraction contains sufficient or excess sulfur, the final activated catalyst can be formed in situ by heating the heavy fraction to a temperature sufficient to release the sulfur. A source of sulfur can thus be H₂S dissolved in the heavy hydrocarbon fraction. or of the HzS contained in recycled hydrogen in the hydroconversion reactor, or of the H:S from organic sulfur molecules present in the heavy hydrocarbon fraction or possibly introduced previously into said heavy fraction (e.g., injection of dimethyl disulfide, thioacetamide, any hydrocarbon feed containing sulfur of the mercaptan type, sulfides, petroleum containing sulfur, diesel containing sulfur, vacuum distillate containing sulfur, residue containing sulfur). Thus, a sulfur source can be sulfur compounds in the heavy hydrocarbon fraction or a sulfur compound added to said heavy fraction. The temperature during preheating of the heavy hydrocarbon fraction and / or in step (b) allows the formation of the metal sulfide catalyst. The concentration of catalyst metal, preferably Mo, in the feed (i.e., the combination of heavy hydrocarbon fraction and plastic fraction) is preferably between 5 ppm and 500 ppm by weight of the feed, more preferably between 10 ppm and 300 ppm by weight, more preferably between 10 ppm and 175 ppm by weight, even more preferably between 10 ppm and 75 ppm by weight, and even more preferably between 10 ppm and 50 ppm by weight. Preferably, the colloidal or molecular catalyst includes molybdenum disulfide. Step (a2) Alternatively, in step (a) the plastic fraction in the form of solid particles can be mixed with a plastic diluent in a mixing section and heated in a heating section so as to obtain an essentially liquid plastic fraction (e.g. at a temperature above the melting temperature of said plastic fraction, preferably between 60°C and 295°C), before its introduction into the first hydroconversion reactor, the heating step being able to be carried out before or after mixing with the plastic diluent, and preferably after mixing with the plastic diluent. Thus, step (a) can be a step (a2) of direct injection of the plastic fraction in an essentially liquid form after said plastic fraction has been mixed with a plastic diluent 107 to form a slurry and then heated so as to obtain an essentially liquid plastic fraction. Figure [Fig. 1B] illustrates this second variant of the first embodiment of the process according to the invention. This variant has the particular advantage of using simple and inexpensive equipment. The plastic fraction in the form of solid particles 102 is pre-mixed with a plastic diluent 107 in a mixing section 11 to form a suspension 108, then said suspension 108 is sent into a heating section 12 to be heated to a temperature above the melting temperature of said plastic fraction, so that the solid particles of the suspended plastic fraction melt, and said heated plastic fraction 109 is introduced into the first hydroconversion reactor of the first hydroconversion section 20. The mixing of the plastic diluent 107 and the plastic fraction in the form of particles 102 in the mixing section 11 is preferably carried out at atmospheric pressure or a pressure close to atmospheric pressure. Preferably, during the mixing step in mixing section 11, the temperature is such that the suspension 108 has a kinematic viscosity of less than 0.3 x 10⁻³ m⁻² / s, corresponding to the viscosity of a pumpable fluid. The temperature at this step is preferably lower than the temperature at the heating step described below, in the case where the mixing steps are separate and precede the heating step. The mixing section 11 may include a mixing tank with means for dynamic mixing for suspension, for example an agitator and / or a recirculation pump. At the end of the heating of the suspension 108, at least 90% by weight of the heated plastic fraction 109 is advantageously in liquid form, very advantageously at least 95% by weight, preferably at least 98% by weight. What has been described for the temperature conditions of extruder 10 in step (al1) applies to the heating of the suspension in step (a2), and is therefore not repeated here. However, it is again specified that the heating temperature may also depend on the plastic diluent 107 used, such a plastic diluent being able in particular, depending on its nature, to allow the suspended plastic fraction to melt at a lower temperature. The heating section 12 includes any heating means known to a person skilled in the art capable of heating a suspended plastic fraction 108. The heating section 12 may include a furnace comprising at least one heating compartment, and / or tubes through which the suspension 108 flows, any type of suitable heat exchanger, etc. According to one configuration, the mixing section 11 and the heating section 12 can be part of the same device configured to implement successively the mixing and then the heating of the step (a2). Before its introduction into the first hydroconversion reactor, the heated plastic fraction 109 undergoes a pressurization step to adapt it to the pressure operated in the first hydroconversion reactor, for example using With a suitable pump, it can also be subjected to a filtration stage aimed, for example, at removing solid particles from the plastic fraction that may be part of the plastic impurities, such as sand, glass, metals, certain additives called "fillers" in English, etc. Separately to the introduction of the heated plastic fraction 109, the heavy hydrocarbon fraction 101 is introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described below is carried out. Prior to its introduction into the first hydroconversion reactor, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. According to another variant of the first embodiment of the process according to the invention not shown, step (a) can be a step (a'2) of direct injection of the plastic fraction in an essentially liquid form after said plastic fraction has been heated so as to obtain an essentially liquid plastic fraction, then mixed with a plastic diluent 107 to form a dilute plastic fraction introduced into the first hydroconversion reactor. According to yet another variant, the mixing and heating stages are carried out simultaneously, with the mixing and heating sections forming part of the same device configured to implement mixing and heating simultaneously. Step (a3) Alternatively, step (a) can be a step (a3) ​​of direct injection of the suspended plastic fraction into the first hydroconversion reactor. Fig. 1C illustrates this third variant of the first embodiment of the process according to the invention. This variant has the particular advantage of using simple and inexpensive equipment. According to step (a3), the plastic fraction in the form of solid particles 102 is first sent into a mixer 13 to be mixed with a plastic diluent 107 and form a suspension 110, then said plastic fraction in the form of suspension 110 is introduced into the first hydroconversion reactor of the first hydroconversion section 20. The mixing of the plastic diluent 107 and the plastic fraction 102 in the mixer is preferably carried out at a temperature greater than or equal to the temperature ambient temperature, e.g. 15°C, and lower than the melting temperature of said plastic fraction (or lower than the melting temperature of the polymer with the lowest melting point if said plastic fraction comprises a mixture of polymers). A temperature slightly lower than the melting temperature of the plastic fraction may constitute the upper limit for the mixture temperature, because the plastic diluent 107 used, depending on its nature, influences the temperature at which the plastic fraction can be dissolved (in the case where the plastic diluent has a solvent function). Depending on the configuration, the mixture can be made at a temperature greater than or equal to 50°C or even 75°C and less than 170°C, for example well suited to the use of a VGO as a plastic diluent and to a plastic fraction consisting mainly of PP as a polymer, or at a temperature greater than or equal to 150°C and less than 170°C, for example well suited to the use of a vacuum residue as a plastic diluent and to a plastic fraction consisting mainly of PP as a polymer. Depending on the configuration, the mixture can be made at a temperature greater than or equal to 50°C or even 75°C and less than 140°C, or even made at a temperature greater than or equal to 50°C or even 75°C and less than 85°C, for example well suited to the use of a VGO as a plastic diluent and to a plastic fraction consisting mainly of PE as a polymer. Depending on the configuration, the mixture can be made at a temperature greater than or equal to 50°C or even 75°C and less than 270°C, or at a temperature greater than or equal to 50°C or even 75°C and less than 240°C, for example well suited to the use of a VGO as a plastic diluent and a plastic fraction consisting mainly of PS as a polymer, or at a temperature greater than or equal to 150°C and less than 270°C, or even less than 240°C, for example well suited to the use of a vacuum residue as a plastic diluent and a plastic fraction consisting mainly of PS as a polymer. The mixing may be active or inactive. Examples of active mixing devices that may be used include, but are not limited to, high-shear mixing such as mixing created in a pump with a propeller or turbine rotor, multiple static inline mixers, multiple static inline mixers in combination with high-shear inline mixers, multiple static inline mixers in combination with high-shear inline mixers, multiple static inline mixers in combination with high-shear inline mixers followed by recirculation pumping into the buffer tank, and combinations of the above devices followed by one or more multi-stage centrifugal pumps. Separately to the introduction of the suspended plastic fraction 110, the heavy hydrocarbon fraction 101 is introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described below is carried out. Prior to its introduction into the first hydroconversion reactor, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. Before their introduction into the first hydroconversion reactor, the suspended plastic fraction 110 and the heavy hydrocarbon fraction 101 can undergo a pressurization step to adapt to the pressure operated in the first hydroconversion reactor. Step (a4) Alternatively, step (a) may be a step (a4) of direct injection of the plastic fraction into the hydroconversion reactor in suspension form via the means of injecting the porous supported hydroconversion catalyst into said hydroconversion reactor. Figure [Fig. 1D] illustrates this fourth variant of the first embodiment of the process according to the invention. This variant has the particular advantage of using existing means of injecting particles (the supported catalyst) into the reactor to inject the plastic fraction of the feed. According to step (a4), the plastic fraction in the form of solid particles 102 is pre-mixed with a plastic diluent 107 and with the first porous supported hydroconversion catalyst in a distribution and mixing box 14 to form a suspension 112, then said suspension 112 is introduced into the first hydroconversion reactor of the first hydroconversion section 20 via catalyst injection means into said reactor. The distribution and mixing box 14 is part of a device for drawing off and injecting porous supported catalyst into the first hydroconversion reactor. Preferably, the plastic fraction in the form of solid particles 102 is sent into the distribution and mixing box 14 intermittently. The first hydroconversion reactor, like each bubbling bed or hybrid hydroconversion reactor used in the process according to the invention, includes means for injecting and withdrawing the supported catalyst from said reactor. Indeed, a key aspect of the operation of bubbling bed or hybrid reactors is the continuous replacement of the supported catalyst. Catalyst replacement is generally required in all hydrocarbon hydroconversion processes, as the supported catalyst is primarily deactivated by the deposition of metals contained in the feedstock, in the form of vanadium sulfide and nickel sulfide, and by coke deposition. While bubbling bed technology does ultimately increase the time between two conversion process shutdowns through continuous catalyst renewal, compared to other technologies such as fixed bed reactors, it necessitates the implementation of a continuous catalyst renewal system, with catalyst removal and replenishment, for example, daily. The spent catalyst, removed from the reactor, can be sent to a regeneration zone where the carbon and sulfur it contains are eliminated.It is also possible to send the spent catalyst removed from the reactor to a rejuvenation zone where most of the deposited metals are removed, before sending the spent and rejuvenated catalyst to a regeneration zone where the carbon and sulfur it contains are removed. The regenerated or rejuvenated catalyst can then be reintroduced into the reactor, possibly in combination with fresh catalyst, by means of catalyst injection. Typically, the means for injecting and withdrawing supported catalyst include at least one conduit opening into the supported catalyst expansion zone of the reactor for introducing fresh (and / or regenerated and / or rejuvenated) supported catalyst into the reactor's supported catalyst expansion zone and for withdrawing spent catalyst from said zone. Introducing and withdrawing can be done with the same conduit, or through separate conduits, in which case at least two conduits are required: one injection conduit for injecting supported catalyst into the reactor and one conduit for withdrawing spent catalyst. According to step (a3), the suspension 112, formed by mixing the plastic fraction in the form of particles 102, the supported catalyst 111, and the plastic diluent 107 in the distribution and mixing box 14, is injected into the reactor via the supported catalyst injection means, in particular through a conduit connected at one end to said distribution and mixing box 14 and opening at its other end into the supported catalyst expansion zone of the first hydroconversion reactor. This conduit may include means for controlling the flow of the injected suspension, for example, valves and / or other elements such as pumps, storage tanks, etc. The means for injecting the supported catalyst into the first hydroconversion reactor are therefore also means for injecting the suspended plastic fraction into said first reactor. Separately, upon the introduction of suspension 112 comprising the fraction plastic and the first supported hydroconversion catalyst, the heavy hydrocarbon fraction 101 is introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described below is carried out. Prior to its introduction into the first hydroconversion reactor, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. Indirect injection: fractions mixed before injection into the hydroconversion reactor According to a second embodiment of the invention, alternative to the first embodiment, in step (a), the plastic fraction and the heavy hydrocarbon fraction of the feed (114, 117, 120, 122, 125) are introduced mixed into said at least one first hydroconversion reactor of the first hydroconversion section 20. Different variants can be implemented, according to the alternative steps (a5S) to (a9) described below in relation to Figures 2A to 2E. These variants are distinguished at a second level by the fact that the plastic fraction is in solid or slurry form (figures 2A and 2B), or alternatively in predominantly liquid form (figures 2C, 2D and 2E) when mixed with the heavy hydrocarbon fraction. Step (a5) Figure 2A illustrates a first variant of the second embodiment, in which the conditioning and injection step (a) of the feedstock is a step (a5) in which the plastic fraction is mixed in solid form with the heavy fraction. This mixture then forms a suspension, and constitutes the feedstock, which is heated to obtain an essentially liquid plastic fraction before the feedstock is introduced into the first hydroconversion reactor of the first hydroconversion section 20. This variant has the particular advantage of injecting into the first hydroconversion reactor a mixture containing a plastic fraction already dispersed in the feed, of allowing good suspension of the plastic fraction thanks to the use of the heavy hydrocarbon fraction for suspension, and of increasing the solubilization rate of the plastic fraction where appropriate. According to step (a5), the plastic fraction in the form of solid particles 102 is first mixed with the heavy hydrocarbon fraction 101 in a mixing device 15, forming a suspension 113. The said mixing in the mixing device 15 is preferably carried out at a temperature greater than or equal to the ambient temperature, e.g. 15°C, and less than the melting temperature of said plastic fraction (or less than the melting temperature of the polymer which has the lowest melting point if said plastic fraction comprises a mixture of polymers). Advantageously, the mixture can be made at a temperature greater than or equal to 50°C or even 75°C, or even greater than or equal to 150°C, and less than 170°C, or even at a temperature greater than or equal to 150°C and less than 170°C, for example well suited to the use of a plastic fraction consisting mainly of PP as a polymer. Advantageously, the mixture can be made at a temperature greater than or equal to 50°C or even 75°C and less than 140°C, or even made at a temperature greater than or equal to 50°C or even 75°C and less than 85°C, for example well suited to the use of a plastic fraction consisting mainly of PE as a polymer. Depending on the configuration, the mixing can be carried out at a temperature greater than or equal to 50°C or even 75°C, or even greater than or equal to 150°C and less than 270°C, or even less than 240°C, for example well suited to the use of a plastic fraction consisting mainly of PS as a polymer. The mixing may be active or not. The same examples of active mixing equipment, but not limited to them, that may be used are those already described in relation to step (a3) ​​for mixing the plastic fraction with the plastic diluent. Prior to its introduction into the mixing device 5, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. The suspension 113 is then heated in a heating device 16, so that the solid particles of the plastic fraction melt. The suspension 113 is thus heated to a temperature above the melting point of the plastic fraction. After heating the suspension 113, at least 90% by weight of the plastic fraction of the charge 114 is advantageously in liquid form, very advantageously at least 95% by weight, and preferably at least 98% by weight. Preferably, suspension 113 is heated to reach a target temperature in the first reactor. Heating is preferably carried out at a temperature between 280°C and 450°C, and even more preferably between 300°C and 400°C, and even more preferably between 320°C and 365°C. This preheating can be carried out at a temperature that is 100°C lower, preferably 50°C lower, than the hydroconversion temperature in the hydroconversion reactor. The heating section 16 includes any means of heating known to a person skilled in the art capable of heating a suspended plastic fraction 113. The heating section 16 may include a furnace comprising, for example, at least one heating compartment, and / or tubes through which the suspension flows, a mixer of the charge with H, any type of suitable heat exchanger, for example tubular or spiral heat exchangers through which the suspension flows, etc. According to one configuration, the mixing section 15 and the heating section 16 can be part of the same device configured to implement successively the mixing and then the heating of the step (a5). The charge 114, in essentially liquid form, and comprising the plastic fraction and the heavy fraction of hydrocarbons in mixture, is then introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described below is carried out. Preferably a pressurization step is carried out after the mixing of the heavy hydrocarbon fraction with the plastic fraction and before the heating section, so that the charge 114 is adapted to the pressure operated in the first hydroconversion reactor. Step (a6) Alternatively, step (a) can be an indirect injection step (a6), in which the plastic fraction is first mixed in solid form with a diluent before being mixed with the heavy fraction. This final mixture then forms a suspension and constitutes the feed, which is heated to obtain an essentially liquid plastic fraction before the feed is introduced into the first hydroconversion reactor of the first hydroconversion section 20. This second variant of the second embodiment of the process according to the invention, illustrated in [Fig.2B], therefore differs only from step (a5) by the premixing of the plastic fraction in the form of particles 102 with a plastic diluent 107 in a first mixer 17 producing a first suspension 115. This variant offers the advantages mentioned for step (a5), as well as better solubilization of the liquid fraction where applicable. The operating conditions of this premix in the first mixer 17, as well as the type of mixing and associated device, are identical to those already described in relation to step (a3) ​​in relation to the mixing of the plastic fraction and the plastic diluent, and are not repeated here. The first suspension 115 is then mixed with the heavy hydrocarbon fraction 101 in a second mixer 18 to form a second suspension 116, in the same manner as described in step (a5) above, and is not repeated here. Prior to its introduction into the mixing device 15, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. The heating of the second suspension 116 in the heating device 19 is also carried out in the same manner as described in step (a5) for the heating of the suspension 113, and allows the solid particles of the plastic fraction to melt. After heating the second suspension 116, at least 90% by weight of the plastic fraction of the feedstock is advantageously in liquid form, very advantageously at least 95% by weight, and preferably at least 98% by weight. The charge 117, resulting from the heating of the second suspension 116 in the heating device 19, comprising the essentially liquid plastic fraction and the heavy fraction of mixed hydrocarbons, is then introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described below is carried out. Step (a7) Alternatively, step (a) can be an indirect injection step (a7), in which the plastic fraction is heated so as to be in a substantially liquid form before being mixed with the heavy hydrocarbon fraction. Figure [Fig. 2C] illustrates this third variant of the second embodiment of the process according to the invention. This variant has the particular advantage of avoiding the management of a suspension of the plastic fraction and of eliminating the need for associated mixing equipment. According to step (a7), the plastic fraction in the form of solid particles 102 is first heated in a melting device 21 in order to melt said plastic fraction. For this purpose, the plastic fraction is heated to a temperature above its melting point. Advantageously, at least 80% by weight of the plastic fraction is in liquid form after this heating, very advantageously at least 90% by weight, preferably at least 95% by weight, or even 98% by weight. What has been described for the temperature conditions of the extruder 10 at step (al) applies to the heating of the plastic fraction in the liquefaction device 21 at this step (a7), and is therefore not repeated here. The melting device 21 includes any heating means known to a person skilled in the art capable of melting a solid plastic fraction. The melting device 21 may include a furnace, a heated pot, etc. The melting device 21 may include mixing means for blending the existing phases during melting. The melting device can be an extruder as described in step (al). The molten plastic fraction 118 is then mixed with the heavy hydrocarbon fraction 101 in a mixer 22, to form a feed 119 which is then introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described later is carried out. The said mixture in the mixer 22 is preferably carried out at a temperature between 85°C, or even 100°C, and 350°C, preferably between 150°C and 250°C. The temperature is advantageously adjusted according to the viscosity of the mixture. Prior to its introduction into the mixing device 22, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. The entrained catalyst precursor 104 can also be mixed with the feed 119 from the mixer 22, before its introduction into the first hydroconversion reactor, in addition to or alternatively to the mixture with the heavy hydrocarbon fraction 101. In this case, the mixture will be similar to that described for the mixture with the heavy hydrocarbon fraction 101. Step (a8) Alternatively, step (a) can be an indirect injection step (a8), in which the plastic fraction is pre-mixed in solid form with a plastic diluent and then heated so as to be in substantially liquid form before being mixed with the heavy hydrocarbon fraction. This fourth variant of the second embodiment of the process according to the invention, illustrated in [Fig.2D], therefore differs only from step (a7) by the premixing of the plastic fraction in the form of particles 102 with a plastic diluent 107 in a premixer 17, producing a suspension 120. This variant has the particular advantage of good dispersion and / or good so- lubrication of the plastic fraction, and provides greater flexibility for mixing with the heavy hydrocarbon fraction, particularly with regard to targeted viscosity. The operating conditions of this premix in the premixer 17, as well as the type of mixing and associated device, are identical to those already described in relation to steps (a3) ​​and (a6) in relation to the mixing of the plastic fraction and the plastic diluent, and are not repeated here. The suspension 120 is then heated in a heating device 23, at a temperature above the melting temperature of said plastic fraction, so that the solid particles of the suspended plastic fraction melt. At the end of the heating of the suspension 120, at least 90% by weight of the plastic fraction is advantageously in liquid form, very advantageously at least 95% by weight, preferably at least 98% by weight. What has been described for the temperature conditions of extruder 10 in step (al) applies to the heating of suspension 120 in step (a8), and is therefore not repeated here. However, it is again specified that the heating temperature may also depend on the plastic diluent 107 used, such a diluent being able in particular, depending on its nature, to allow the suspended plastic fraction to melt at a lower temperature. The heating section 23 includes any heating means known to a person skilled in the art capable of heating a suspended plastic fraction 120. The heating section 23 may include a furnace comprising at least one heating compartment, and / or tubes through which the suspension 120 flows, any type of suitable heat exchanger, etc. According to one configuration, the mixing section 17 and the heating section 23 can be part of the same device configured to implement successively the mixing and then the heating of the step (a8). The molten diluted plastic fraction 121 is then mixed with the heavy hydrocarbon fraction 101 in a mixer 22 in the same manner as described in step (a7) for mixer 22, to form a feed 122 which is then introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described later is carried out. Prior to its introduction into the mixer 22, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here. same way and is not repeated. The entrained catalyst precursor 104 can also be mixed with the feed 122 from the mixer 22, before its introduction into the first hydroconversion reactor, in addition to or alternatively to the mixture with the heavy hydrocarbon fraction 101. In this case, the mixture will be similar to that described for the mixture with the heavy hydrocarbon fraction 101. The entrained catalyst precursor 104 can further be mixed with the liquid plastic fraction 121 before its mixing with the heavy hydrocarbon fraction in the mixer 22, in addition to or alternatively to a mixture of the precursor with the heavy hydrocarbon fraction 101 or with the feed 122. In this case, the mixture will be similar to that described for the mixture with the heavy hydrocarbon fraction 101. Step (a9) Alternatively, step (a) may be an indirect injection step (a9), in which the plastic fraction is heated so as to be in a substantially liquid form, then mixed with a diluent before being mixed with the heavy hydrocarbon fraction. Figure [Fig. 2F] illustrates this fifth variant of the second embodiment of the process according to the invention. This variant has the particular advantage of good dispersion and / or good solubilization of the plastic fraction. According to step (a9), the plastic fraction in the form of solid particles 102 is first heated in a melting device 24 in order to melt said plastic fraction, in the same manner as described in step (a7). Thus, for this purpose, the plastic fraction is heated to a temperature above its melting point. Advantageously, at least 80% by weight of the plastic fraction is in liquid form after this heating, very advantageously at least 90% by weight, preferably at least 95% by weight, or even 98% by weight. What has been described for the temperature conditions of the extruder 10 in step (al) applies to the heating of the plastic fraction in the melting device 24 in this step (a9), and is therefore not repeated here. The fusion device 24 is identical to that described in step (a7) for the fusion device 21, and is not repeated here. The molten plastic fraction 123 is then mixed with a plastic diluent 107 in a first mixer 25, to form a diluted molten plastic fraction 124. The said mixing in the first mixer 25 is preferably carried out at a temperature higher than the melting temperature of the plastic fraction (for example, super- greater than 85°C, or even greater than 100°C) and less than or equal to 350°C, and preferably between 150°C and 250°C. The first mixer may include a static mixer or a dynamic mixer such as a stirred tank, and preferably includes a static mixer. The diluted molten plastic fraction 124 is then mixed with the heavy hydrocarbon fraction 101 in a second mixer 26, to form a feed 125 which is then introduced into the first hydroconversion reactor of the first hydroconversion section 20, and the hydroconversion step (b) as described later is carried out. The said mixture in mixer 26 is preferably similar to that described in step (a7) for mixer 22. Prior to its introduction into the mixing device 26, the heavy hydrocarbon fraction 101 can be mixed with a precursor of an entrained catalyst 104, so that, during the formation of the entrained catalyst, particularly by reaction with sulfur, the entrained catalyst will include a colloidal or molecular catalyst dispersed in the feed. What was described in this regard in step (a1a) applies here in the same way and is not repeated. The entrained catalyst precursor 104 can also be mixed with the dilute molten plastic fraction 124 before its mixing with the heavy hydrocarbon fraction in the mixer 26, in addition to or alternatively to a mixture of the precursor with the heavy hydrocarbon fraction 101. In this case, the mixture will be similar to that described for the mixture with the heavy hydrocarbon fraction 101. The entrained catalyst precursor 104 can also be mixed with the hydrocarbon diluent, as already described above in relation to step (al) and [Fig. 1 A] in relation to the catalyst precursor, before its mixing with the molten plastic fraction 123 in the mixer 25, in addition to or alternatively to a mixture of the precursor with the heavy hydrocarbon fraction 101 or with the diluted molten plastic fraction 124. In this case, the mixture will be similar to that described for the mixture with the heavy hydrocarbon fraction 101. (b) first hydroconversion stage The feed (101, 102, 114, 117, 119, 122, 125) is introduced, whether its component fractions are separated or mixed, into the first hydroconversion reactor of the first hydroconversion section 20, together with hydrogen. Said first reactor comprises a first porous supported hydroconversion catalyst. The first hydroconversion step (b) is carried out under conditions enabling the production of a first hydroconverted effluent 105. Said first hydroconverted effluent 105 contains the conversion products, in particular the said first effluent has a reduced content of hydrocarbons having a boiling point of at least 300°C. The said first hydroconverted effluent 105 may also have a reduced content of sulfur, and / or metals, and / or nitrogen, and / or Conradson carbon, and / or asphaltenes, depending on the reactions implemented in the first hydroconversion reactor. Step (b) is preferably carried out under an absolute pressure between 2 MPa and 38 MPa, more preferably between 5 MPa and 25 MPa, and even more preferably between 6 MPa and 20 MPa, at a temperature between 300°C and 550°C, more preferably between 350°C and 500°C, and preferably between 370°C and 450°C. The hourly space velocity (VVH) relative to the volume of each reactor is preferably between 0.05 h⁻¹ and 10 h⁻¹. According to a preferred implementation, the VVH 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⁻¹, and even more preferably between 0.15 h⁻¹ and 1 h⁻¹. According to another implementation, the VVH is between 0.05 h⁻¹ and 0.09 h⁻¹. The quantity of hydrogen mixed with the charge is preferably between 50 and 5000 normal cubic meters (Nm°) per cubic meter (m°) of liquid charge, preferably between 100 Nm' / m° and 2000 Nm' / m° and most preferably between 200 Nm? / m° and 1000 Nm? / m°. The first hydroconversion section 20 comprises one or more bubbling or hybrid bed reactors, containing at least one first supported hydroconversion catalyst, the reactors being able to be arranged in series and / or in parallel. At this stage, at least one first supported hydroconversion catalyst is therefore maintained in the reactor(s). According to one or more embodiments of the invention, the first hydroconversion section 20 comprises one or more hydroconversion reactors, which may be in series and / or in parallel, operating in a bubbling bed, as used for the H-Oil™ process, as described, for example, in patents US4521295 or US4495060 or US4457831 or US4354852, in the article Aiche, March 19-23, 1995, Houston, Texas, article number 46d, "Second generation bubbling bed technology", or in Chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" from the book "Catalysis by Transition Metal Sulphides", Technip Editions, 2013. According to this implementation(s), each reactor is operated in a fluidized bed, also known as a bubbling bed. Each reactor advantageously includes a recirculation pump which makes it possible to maintain the porous supported solid catalyst in a bubbling bed by continuously recycling at least part of a liquid fraction drawn from the upper part of the reactor and reinjected at the lower part of the reactor. The bubbling bed reactor preferably includes at least one inlet port located at or near the bottom of the reactor through which the feedstock is introduced along with hydrogen, and in particular two inlet ports in the case where the plastic fraction of the feedstock is introduced separately from the heavy hydrocarbon fraction, and an outlet port at or near the top of the reactor through which the first hydroconverted effluent is withdrawn. The reactor also preferably includes an inlet and an outlet for the supported catalyst as described above, in connection with the means for injecting and withdrawing the supported catalyst. The bubbling bed reactor further includes an expanded catalyst zone comprising the porous supported catalyst.The bubbling bed reactor also includes a lower supported catalyst-free zone located below the expanded catalyst zone, and an upper supported catalyst-free zone located above the expanded catalyst zone. The feed in the bubbling bed reactor is continuously recirculated from the upper supported catalyst-free zone to the lower supported catalyst-free zone by means of a recycle line connected to a boiling pump. Preferably, a funnel-shaped recycle cup is located at the top of the recycle line, through which the feed is drawn from the upper supported catalyst-free zone. The internal recycled feed is mixed with fresh feed and additional hydrogen gas. The first supported hydroconversion catalyst used in the first hydroconversion step (b) may contain one or more elements from groups 4 to 12 of the periodic table, which may or may not be deposited on a support. Advantageously, a catalyst comprising an amorphous support, such as silica, alumina, silica-alumina, titanium dioxide, or combinations of these structures, and alumina, may be used. The first supported catalyst may contain at least one non-noble group VIII metal selected from nickel and cobalt, and preferably nickel, said group VIII element preferably being used in association with at least one group VIB metal selected from molybdenum and tungsten, and preferably the group VIB metal is molybdenum. In this description, chemical element groups are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals in columns 8, 9, and 10 according to the new IUPAC classification. Advantageously, the first supported hydroconversion catalyst used in the first hydroconversion step (b) comprises an alumina support and at least one a metal from group VIII selected from nickel and cobalt, preferably nickel, and at least one metal from group VIB selected from molybdenum and tungsten, preferably molybdenum. Preferably, the first supported hydroconversion catalyst comprises nickel as a group VIII element and molybdenum as a group VIB element. The content of non-noble Group VIII metals, particularly 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 metals, particularly molybdenum, is advantageously between 1% and 30% expressed by weight of metal oxide (in particular molybdenum trioxide, MoO2), and preferably between 4% and 20% by weight. Metal contents are expressed as a percentage by weight of metal oxide relative to the weight of the catalyst. This first supported catalyst is advantageously used in the form of extrudates or beads. The beads, for example, have a diameter between 0.4 mm and 4.0 mm. The extrudates, for example, have a cylindrical shape with a diameter between 0.5 mm and 4.0 mm and a length between 1 mm and 5 mm. Extrudates can also be objects of a different shape, such as trilobes, regular or irregular tetralobes, or other multilobes. Porous supported catalysts of other shapes can also be used. The size of these different shapes of porous supported catalysts can be characterized by means of the equivalent diameter. The equivalent diameter is defined as six times the ratio between the particle volume and the particle's external surface area. The porous supported catalyst, used in the form of extrudates, beads, or other shapes, thus has an equivalent diameter between 0.4 mm and 4.4 mm.These catalysts are well known to those skilled in the art. According to one or more embodiments of the invention, the first hydroconversion section 20 comprises one or more hybrid bed reactors (i.e., bubbling-entrained hybrid beds), simultaneously comprising at least one first supported hydroconversion catalyst that is maintained in the reactor and at least one entrained catalyst that enters the reactor with the feed and is entrained out of the reactor with the effluents. In this case, as already described above in relation to step (a), an entrained catalyst precursor was introduced before the feed was injected into the first hydroconversion reactor, and a colloidal or molecular catalyst, also called a dispersed, entrained, or slurry catalyst, could form upstream or in situ in the hybrid bed hydroconversion reactor. These entrained catalysts are well known to those skilled in the art. The hybrid bed reactor comprises a solid phase containing a porous supported catalyst in the form of an expanded bed, and a liquid hydrocarbon phase. including the charge containing the colloidal or molecular catalyst dispersed therein, and a gaseous phase comprising hydrogen. The hybrid bed reactor is a bubbling bed hydroconversion reactor as described above, but comprising, in addition to the porous supported catalyst in the form of an expanded bed maintained in the reactor, the molecular or colloidal catalyst carried out of the reactor with the hydroconverted liquid effluent 105. According to one or more embodiments, the operation of the hybrid bed hydroconversion reactor is based on that of the bubbling bed reactor already described, and further implies that the colloidal or molecular catalyst is dispersed throughout the feed in the hybrid bed reactor, including both in the expanded catalyst zone and in the areas free of supported catalyst, and therefore available to stimulate valorization reactions in what constitute catalyst-free areas in conventional bubbling bed reactors. The presence of colloidal or molecular catalyst in the hybrid bed reactor provides additional catalytic hydrogenation activity, both in the expanded catalyst zone, in the recycle channel, and in the lower and upper catalyst-free zones. Capping free radicals outside the porous supported catalyst minimizes the formation of sediments and coke precursors, which are often responsible for supporting catalyst deactivation. This can allow a reduction in the amount of porous supported catalyst that would otherwise be required to carry out a desired hydroconversion reaction. This can also reduce the rate at which the porous supported catalyst needs to be withdrawn and replenished. In one embodiment of the process according to the invention, a different first supported hydroconversion catalyst can be used in each reactor of the first hydroconversion section, the supported catalyst specific to each reactor being adapted to the feed introduced into that reactor. In one embodiment of the process according to the invention, several types of first supported catalyst are used in each reactor. As is known, and for example described in patent FR3033797, the first supported hydroconversion catalyst, when used, can be partially replaced by fresh supported catalyst, and / or used supported catalyst but with a higher catalytic activity than the used supported catalyst to be replaced, and / or regenerated supported catalyst, and / or rejuvenated supported catalyst (catalyst from a rejuvenation zone in which most of the deposited metals are removed, before sending the used and rejuvenated catalyst to a regeneration zone in which the carbon and sulfur it contains are removed, thus increasing the catalyst's activity), by withdrawing the used supported catalyst, preferably from the bottom of the reactor, and by in- The replacement supported catalyst is introduced either at the top or the bottom of the reactor. This replacement of the spent supported catalyst is preferably carried out at regular time intervals, and preferably in bursts or almost continuously. This withdrawal and replacement are performed using a withdrawal and injection device that advantageously allows the continuous operation of this hydroconversion step. An example of such a device has already been described in connection with step (a), which can also allow the introduction of the plastic fraction according to a specific implementation (see step (a4)). With this withdrawal / injection mechanism for the supported catalyst, it is therefore unnecessary to stop the unit to change the spent catalyst, nor to increase reaction temperatures throughout the cycle to compensate for deactivation. Furthermore, operating under constant conditions ensures consistent yields and product quality throughout the cycle. Also, because the supported catalyst is kept agitated by significant liquid recycling, the pressure drop across the reactor remains low and constant, and the reaction exotherms are rapidly averaged over the catalytic bed, which is therefore nearly isothermal and does not require the injection of cooling fluxes (quenches). According to one or more embodiments, when step (b) is implemented in one or more hybrid bed reactors, the feed or entrained catalyst precursor may be premixed with an organic additive, before the feed is introduced into the first hydroconversion reactor of the first hydroconversion section 20, in particular to minimize fouling of the facilities prior to hydroconversion in the hybrid bed reactor(s).Without being linked to any specific theory, the organic additive, when mixed with the feedstock, improves the solubility of the catalyst precursor carried along with the feedstock, preventing or reducing fouling, particularly due to metallic deposits in the upstream installations of the hydroconversion reactor, such as in heating devices. This improves the dispersion of the carried catalyst, thereby increasing the availability of metallic active sites, promoting the hydrogenation of free radicals that are precursors of coke and sediment, and generating a substantial reduction in plant fouling. This organic additive, which is neither a catalyst nor a catalyst precursor (i.e., it does not contain any metal), possesses at least one carboxylic acid functional group and / or at least one ester functional group and / or at least one acid anhydride functional group.It preferably comprises at least 6, or even at least 8, carbon atoms, and more preferably at least 8 carbon atoms. For example, the organic additive may be 2-ethylhexanoic acid, naphthenic acid, caprylic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, ethyl octanoate, ethyl 2-ethylhexanoate, etc. 2-ethylhexyl 2-ethylhexanoate, benzyl 2-ethylhexanoate, diethyl adipate, dimethyl adipate, bis(2-ethylhexyl) adipate, dimethyl pimelate, dimethyl suberate, monomethyl suberate, hexanoic anhydride, caprylic anhydride, and mixtures thereof. The organic additive is preferably added during the mixing step so that the molar ratio of organic additive to the active metal(s) of the catalyst precursor composition (e.g., Mo) is between 0.1:1 and 20:1, more preferably between 0.75:1 and 7:1, and even more preferably between 1:1 and 5:1. (c) Optional intermediate separation step According to one or more preferred embodiments, the process further includes a separation step (c), which separates part, or all, of the first hydroconverted effluent 105, to produce at least two cuts, including a heavy cut boiling predominantly at a temperature greater than or equal to 350°C. The other fraction(s) are one or more light and intermediate fractions. The light fraction thus separated contains mainly gases (H₂, H₂S, NH₃, and C₂-C₆), naphtha (fraction that boils at a temperature below 150°C), kerosene (fraction that boils between 150°C and 250°C), and at least some of the diesel (fraction that boils between 250°C and 375°C). The light fraction can then be sent, at least partially, to a fractionation unit (not shown in the figures) where the light gases are extracted from said light fraction, for example, by passing through an expansion vessel. The gaseous hydrogen thus recovered, which may have been sent to a purification and compression plant, can advantageously be recycled to the first hydroconversion stage (b), and / or to the second hydroconversion stage (d) if it is implemented. The recovered gaseous hydrogen can also be used in other refinery facilities. The optional separation step (c) is carried out in a separation section (not shown in the figures), which includes any separation means known to a person skilled in the art. This separation section may include one or more expansion flasks arranged in series, and / or one or more steam and / or hydrogen stripping columns, and / or an atmospheric distillation column, and / or a vacuum distillation column, and preferably consists of a single expansion flask, commonly referred to as a "hot separator". (d) optional second hydroconversion step According to one or more preferred embodiments (not shown in the figures), the process further comprises a second hydroconversion step, in at least one second bubbling bed or hybrid bed reactor comprising a second porous supported catalyst, in the presence of hydrogen, part or all of the The entirety of the first effluent 105 resulting from step (b), or optionally of the heavy cut from step (c). This second hydroconversion step is carried out so as to produce a second hydroconverted effluent. This second hydroconverted effluent advantageously contains a greater quantity of conversion products than the first hydroconverted effluent, and in particular an even lower content of hydrocarbons having a boiling point of at least 300°C. The second hydroconverted effluent may have a reduced Conradson carbon residue, and optionally a reduced quantity of sulfur, and / or nitrogen, and / or metals, and / or asphaltenes. The second hydroconversion stage is carried out in a similar manner to that described for the first hydroconversion stage (b), and is not repeated here. This applies in particular to the operating conditions, the equipment used, and the porous supported hydroconversion catalysts used, with the exception of the details mentioned below. As with the first hydroconversion step (b), the second hydroconversion step is carried out in at least one second bubbling bed or hybrid reactor. It is preferably carried out in one or more bubbling bed reactors if the first hydroconversion step is also carried out in one or more bubbling bed reactors, and it is preferably carried out in one or more hybrid bed reactors if the first hydroconversion step is carried out in one or more hybrid bed reactors. In this second hydroconversion stage, the operating conditions may be similar or different from those in the hydroconversion stage (d), the temperature remaining in the range between 300°C and 550°C, preferably between 350°C and 500°C, more preferably between 370°C and 450°C, more preferably between 400°C and 440°C, and even more preferably between 410°C and 435°C, and the quantity of hydrogen introduced into the reactor remains in the range between 50 Nm' / m° and 5,000 Nm* / m° of liquid charge, preferably between 100 Nm* / m° and 3,000 Nm* / m°, and even more preferably between 200 Nm° / m° and 2,000 Nm° / m°. The other pressure and VVH parameters are in the same ranges as those described for the hydroconversion step (d). The operating temperature in the second hydroconversion stage (d) can be higher than the operating temperature in the first hydroconversion stage (b). This can allow for more complete conversion of the unconverted feedstock. Hydroconversion of liquid products from the first hydroconversion stage and feedstock conversion are enhanced, as are hydrotreating reactions such as hydrodesulfurization and hydrodeazotation, among others. Operating conditions are chosen to minimize the formation of solids (e.g., coke). The second porous supported hydroconversion catalyst used in the second hydroconversion reactor may be the same as that used in the first hydroconversion reactor(s) of the first hydroconversion section 20, or may be another porous supported catalyst also suitable for hydroconversion of the feed-treated, as defined for the first supported catalyst used in the first hydroconversion step (b). (e) splitting step The first hydroconverted effluent 105 from the hydroconversion step (b), or from the second hydroconversion step (d) if such a step is implemented, then undergoes at least part of a fractionation step (e) in a fractionation section 30. This fractionation step (e) separates part or all of the hydro-converted effluent into several fractions, including at least one heavy liquid product 106b that boils predominantly at a temperature above 350°C, preferably above 500°C, and preferably above 540°C. The heavy liquid product 106b contains a portion that boils at a temperature above 540°C, called the residual fraction (or vacuum residue), which is the unconverted portion. The heavy liquid product 106b may contain a portion of the diesel fraction that boils between 250°C and 375°C and a portion that boils between 375°C and 540°C (also called the vacuum distillate). This fractionation step therefore produces at least two products, including the heavy liquid product 106b as described above, the other product(s) 106a being light and intermediate cut(s). The splitting section 30 includes any means of separation known to a person skilled in the art. The fractionation section 30 can thus include one or more of the following separation equipment: one or more flash balloons arranged in series, and preferably a chain of at least two successive flash balloons, one or more steam and / or hydrogen stripping columns, an atmospheric distillation column, a vacuum distillation column. According to one or more embodiments, this fractionation step (e) is carried out by a sequence of at least two successive flash balloons. According to one or more other embodiments, this fractionation step (e) is carried out by one or more steam and / or hydrogen stripping columns. According to one or more preferred embodiments, this fractionation step (e) is carried out by an atmospheric distillation column, and more preferably by an atmospheric distillation column and a vacuum column receiving the atmospheric residue. Depending on the most preferred embodiment(s), this fractionation step (e) is carried out by one or more flash balloons, an atmospheric distillation column and a vacuum column receiving the atmospheric residue. This configuration makes it possible to reduce the size of any downstream deasphalter, thus minimizing investment and operating costs. The fractionation section 30 can also receive, in addition to part or all of the hydroconverted liquid effluent, one or more additional effluents such as one or more hydrocarbon feedstocks external to the process (e.g. atmospheric and / or vacuum distillates, atmospheric and / or vacuum residues), part of the heavy cut from the separation step (c) if implemented, part of one or more of the intermediate cuts from the fractionation step (e), part of a DAO or a light or heavy fraction of a DAO if a deasphalting step (f1) is carried out. (f) further processing step(s) One or more further processing steps (f) of the heavy liquid product 106b and / or of the other product(s) from the fractionation step (e) may be carried out. The various hydrocarbon products that can result from the fractionation step (e) in the fractionation units 30 can be sent to different processes in the refinery, illustrated in the figures under general reference 40, and the details of these post-treatments are not described here as they are generally known to those skilled in the art. For example, gaseous fractions, naphtha, middle distillates, VGO, and DAO can be sent to hydrotreating, steam cracking, fluidized bed catalytic cracking (FCC), hydrocracking, lubricating oil extraction, and other processes. Residues (atmospheric or vacuum residues) can also be post-treated or used for other applications such as gasification, bitumen production, heavy fuel oils, etc.Heavy fractions, including residues, can also be recycled in the hydroconversion process, for example in a hydroconversion reactor at stage (b) or (d). According to one or more embodiments, the hydroconversion process includes a deasphalting step (f1), in a deasphalter, of part or all of said heavy liquid product 106b obtained in the fractionation step (e), with at least one hydrocarbon solvent, to produce a deasphalted oil DAO and a residual asphalt (step “SDA” for Solvent DeAsphalting in English). This deasphalting step (f1) is carried out under conditions well known to those skilled in the art. Reference can be made to the article by Billon et al. published in 1994 in Volume 49, No. 5 of the Revue de l'Institut Français du Pétrole, pages 495 to 507, to the book "Refining and Conversion of Heavy Petroleum Products" by JF Le Page, SG Chatila and M Davidson, Technip Edition, pages 17-32, or to patents US4239616, US4354922, US4354928, US4440633, US4536283, and US4715946. Deasphalting Deasphalting can be carried out in one or more mixer-settlers or in one or more extraction columns. The deasphalter thus comprises at least one mixer-settler or at least one extraction column. Deasphalting is a liquid-liquid extraction generally performed at an average temperature between 60°C and 250°C with at least one low-boiling hydrocarbon solvent, preferably a paraffinic solvent, and preferably heavier than propane, preferably having 3 to 7 carbon atoms. Preferred solvents include propane, butane, isobutane, pentane, isopentane, neopentane, hexane, isohexanes, C5 hydrocarbons, heptane, C7 hydrocarbons, light, more or less nonpolar gasolines, as well as mixtures obtained from the aforementioned solvents. Preferably, the solvent is butane, pentane or hexane, as well as mixtures thereof.The solvent / feed ratios (volume / volume) entering the deasphalter are generally between 3:1 and 16:1, and preferably between 4:1 and 8:1. Preferably, the deasphalter comprises at least one extraction column, and preferably only one (e.g., as implemented in the Solvahl™ process), in which the solvent / feed ratios (volume / volume) entering the deasphalter are preferably low, typically between 4:1 and 8:1, or even between 4:1 and 6:1. The deasphalter produces a DAO that is practically free of C-asphaltenes, said C-asphaltene content being preferably less than 2% by weight, more preferably less than 0.5% by weight, and even more preferably less than 0.05% by weight, and a residual asphalt concentrating most of the impurities in the residue, said residual asphalt being withdrawn.The yield in DAO is generally between 40% by weight and 95% by weight depending on the operating conditions and the solvent used, and depending on the load sent to the desasphalter and in particular the quality of the heavy liquid product 106b. . When recycling a portion of the heavy residue fraction (e.g., a portion of the heavy liquid product 106b and / or a portion of the residual asphalt, or a portion of the DAO) within the hydroconversion system (e.g., in the first hydroconversion reactor or upstream), it can be advantageous, in the case of hybrid bed reactor operation, to leave the catalyst entrained in the residue and / or the residual asphalt fraction. A purge of the recycled stream can be implemented, generally to prevent certain compounds from accumulating at excessive levels. Examples The examples below are intended to show certain performance aspects of the process according to the invention. These examples illustrate the possibility of chemical recycling of plastics in A boiling bed hydroconversion process of the H-Oil™ type converts these materials into lighter hydrocarbons, which can in turn serve as raw materials for new plastics or as bases for manufacturing fuels, lubricants, or any other petroleum refining product. The method of introducing these plastics, initially as solid particles that are dispersed, melted, and dissolved in a mixer prior to the reaction, is also illustrated. The experiments in this example were carried out in a closed reactor (known as a "batch" reactor), representative of the H-Oil™ process. Example | is a comparative example illustrating the performance of the hydroconversion process for a feedstock without plastic material. Example 2 illustrates the performance of an H-Oil"M process with a feed comprising the plastic fraction and the heavy fraction as defined below, with implementation of a pre-dispersion / dissolution step enabling the conversion of said plastic into lighter hydrocarbons of the light, medium or vacuum distillate type which can be utilized in the refinery. Charge : The heavy fraction (I) of the feedstock is a vacuum residue known as straight-run (RSV-SR) originating directly from crude oil distillation. The plastic fraction (IT) of the feedstock is polyethylene from conventional sorting channels, which has been pre-treated and contains less than 0.5% mineral additives. It is in the form of solid particles with dimensions ranging from 500 µm to a maximum of 5 mm. The main characteristics of these two fractions of the charge are presented in Table 1 below. [Table 1] |Fraction I |Fraction II | RSV-SR - |Plastic | 1.002 ne born Charge for hydroconversion Charge Density Viscosity at 100 °C [Conradson Carbon] |< 02 |ez Asphaltenes | |5.3 |ne |C5 Asphaitenes (0% | 10.5 |ne 6,262 < 500 |< 0.1 |15 [ne [Content at 540°C+ fe as 100* Nickel + Vanadium | |ppm 310 Other metals 26 Nitrogen 6030 Sulfur % 2.84 mass. |Content at 350-540°C Ë |1s mass. [Content at 540°C+ |% qss— mass. (*) The entire plastic fraction is considered to belong to the 540°C+ cut (i.e., the cutting boiling at a temperature greater than or equal to 540°C). The operating conditions of these two examples are summarized in Table 2 below. [Tables 2] Experiment 1 (reference) 2 (with plastic) Load | Fraction I (100% mass) | Fraction I (90% mass) + Fraction II (10% mass) Dissolution hold time |h nc 1 Dissolution hold temperature |°C [ne 200 °c |430 min |300 [MPa |16 min! |1000 Dissolution rest duration |h Dissolution rest temperature |°C [resolution Reaction temperature °C 430 Reaction time min |300 |Initial hydrogen pressure [MPa |16 Reaction pressure Stirring speed min |1000 Procedure for example 1: The batch reactor is loaded with 100% RSV-SR (fraction I of the feed), preheated to 50°C–100°C to reduce its viscosity. The reactor is closed, purged with nitrogen, purged with hydrogen, and then pressurized with hydrogen to a pressure of approximately 3 MPa. The reactor is then heated to 100°C. At this temperature, stirring is started at 500 rpm. Gradually, the temperature is raised from 100°C to the reaction temperature, and simultaneously, the stirring speed is gradually increased from 500 to 1000 rpm. When the reaction temperature is reached, the pressure in the reactor is instantly adjusted to the target value by adding hydrogen. At this point, the reaction time is counted. At the end of the experiment, the reactor is rapidly cooled to stop the reaction, stirring is stopped when the reactor is at room temperature, and the liquid effluent and gases are collected for analysis. Procedure for example 2: The batch reactor is first loaded with 90% RSV-SR (fraction I of the feed), then the 10% plastics (fraction II of the feed) are added and manually dispersed for a few seconds in the RSV-SR, which has been preheated to 50°C-100°C to reduce its viscosity. To ensure perfect homogeneity of the mixture, the reactor is closed, purged with nitrogen, purged with hydrogen, and then pressurized with hydrogen to a pressure of approximately 3 MPa. The reactor is then heated to 100°C. At this temperature, agitation is started at 500 rpm. Gradually, the temperature is raised from 100°C to 200°C and, in In parallel, the stirring speed is gradually increased from 500 to 1000 rpm. At 200°C, the pressure in the reactor is then 4 MPa. A one-hour hold at this temperature is observed to ensure proper dissolution and dispersion of the plastic (fraction II of the feed) in the RSV-SR (feed D). Following this hold, the batch reactor is heated to the reaction temperature, at which point the pressure in the reactor is instantly adjusted to the target value by adding H₂. At this point, the reaction time is counted. At the end of the experiment, the reactor is rapidly cooled to stop the reaction, stirring is stopped when the reactor reaches ambient temperature, and the liquid effluent and gases are collected for analysis. Overall results and performance: The results concerning the quality of the total liquid effluent and the hydroconversion performance of these two examples are detailed in Table 3 below. [Tables 3] Experiment _ [Example 1 (reference) Joss 035 [Delta Ni+V Nitrogen Sulfur poz +00 cn [03 I. po [07 [32 [= 1.9 (258 for 30, ,1 [+43 +1.5 7.8 90.2 The conversion of the 540°C+ cut is calculated by the difference in mass between the feed and the total liquid effluent, such that: prod + © ple\ {1 _ Mass 540” ° C ef luent)x100 Conversion 540 c|%)=[1 rss UF TE created A slight decrease in yields was observed in C1-C4 cuts (0.7 points), in light distillates (PI-180°C) (3.2 points), and in medium distillates (180-350°C) (1.9 points), along with a significant increase in the yield of vacuum distillates (350-540°C) (4.3 points) compared to Example 1. The main gain, therefore, lies in the production of vacuum distillates, which can be used in other refinery processes. It was also observed that the hydroconversion performance for the test with plastic was virtually identical to that obtained with the reference Example 1 at a temperature of 430°C for a residence time of 300 minutes, indicating the conversion of the plastic fraction.

Claims

Demands

1. A hydroconversion process for a charge comprising the following steps: following cessives: (a) the conditioning and introduction of said load into a first hydroconversion section (20) comprising at least one first boiling bed or hybrid bed hydroconversion reactor bubbling-driven comprising a first supported catalyst porous hydroconversion, said filler comprising between 1% and 50% in weight of a plastic fraction and 50% and 99% by weight of a fraction heavy hydrocarbons containing a portion of at least 50% by weight having a boiling point of at least 300°C, and containing sulfur, and nitrogen; (b) a first hydroconversion step of said charge in the presence of hydrogen in said first hydroconversion section (20) for obtain a first hydroconverted effluent (105); (c) optionally a step of separating part or all said first effluent resulting from step (b), to form at least one heavy cutting, boiling mostly at a higher temperature or equal to 350°C; (d) optionally a second hydroconversion step in a second hydroconversion section comprising at least a second bubbling bed or hybrid bed hydroconversion reactor bubbling-entrained from part or all of the said first effluent resulting from step (b) or optionally from said cut heavy output of step (c), said second hydroconversion reactor comprising a second supported porous catalyst operating in presence of hydrogen, to produce a second hydro- effluent converted; step (b) and the optional step (d) being implemented at a pressure absolute pressure between 2 MPa and 38 MPa, at a temperature between between 300°C and 550°C, at an hourly spatial velocity relative to the volume of each hydroconversion reactor between 0.05 h! and 10 h", and with a quantity of hydrogen between 50 Nm' / m° and 5000 Nm / m°, (e) a fractionation step of all or part of said first effluent hydroconverted from step (b) or said second hydro- effluent converted from step {d), in a splitting section (30), to produce at least one heavy liquid product (106b) that boils predominantly at a temperature greater than or equal to 350°C, said heavy liquid product containing a residual fraction which boils at a temperature greater than or equal to 540°C.

2. The method according to claim , wherein, in step (a), the fraction plastic and the heavy hydrocarbon fraction of the load (114, 117, 120, 122, 125) are introduced mixed into said at least one first hydroconversion reactor of the first section hydroconversion (20).

3. A method according to claim 2, wherein, in step (a), the fraction plastic in the form of solid particles (102) is mixed with the heavy hydrocarbon fraction (101) so as to form a suspension (113), said suspension (113) being heated to a temperature higher than the melting point of said fraction plastic to form the charge (114) introduced into the first reactor hydroconversion.

4. A method according to claim 2, wherein, in step (a), the fraction plastic in the form of solid particles (102) is previously mixed with a plastic thinner (107) to form a first suspension (115), then said first suspension (115) is mixed with the heavy hydrocarbon fraction (101) so as to form a second suspension (116), said second suspension (116) being heated to a temperature above the melting point of said plastic fraction to form the charge (117) introduced into the first hydroconversion reactor.

5. A method according to claim 2, wherein, in step (a), the fraction plastic in the form of solid particles (102), preferably pre- lightly mixed with a plastic thinner (107) to form a suspension (120), is heated to a temperature above the melting temperature of said plastic fraction to form a molten plastic fraction (118, 121), then said plastic fraction molten (118, 121) is mixed with the heavy hydrocarbon fraction (101) so as to form the charge (119, 122) introduced into the first hydroconversion reactor.

6. A method according to claim 2, wherein, in step (a), the fraction plastic in the form of solid particles (102) is heated to a temperature higher than the melting point of said fraction plastic to form a molten plastic fraction (123), then said molten plastic fraction (123) is mixed with a plastic diluent (107) to form a diluted molten plastic fraction (124) mixed with the heavy hydrocarbon fraction (101) to form the charge (125) introduced into the first hydroconversion reactor

7. Process according to claim 1, wherein, in step (a), the fraction plastic (103, 109, 110, 112) and the heavy hydrocarbon fraction (101) of the charge are introduced separately into said at least one first hydroconversion reactor of the first section hydroconversion (20).

8. A method according to claim 7, wherein, in step (a), the fraction plastic in the form of solid particles (102) is sent into a extruder (10), preferably with a plastic thinner (107), in which it is gradually heated to a sufficient temperature above the melting temperature of said plastic fraction, and placed at the pressure of said first hydroconversion reactor during a transport preferably for a duration of less than 15 minutes, and said extruded plastic fraction (103) is introduced into the first hydroconversion reactor.

9. A method according to claim 7, wherein, in step (a), the fraction plastic in the form of solid particles is mixed with a diluent plastic (107) in a mixing section (11) and heated in a heating section (12) at a temperature higher than the temperature melting of said plastic fraction, preferably between 60°C and 295°C, before its introduction into the first reactor hydroconversion, the heating stage can be carried out before or after mixing with the plastic thinner, and preferably after the mix with the plastic thinner.

10. A method according to claim 7, wherein, in step (a), the fraction plastic in the form of solid particles is previously sent in a mixer (13) to be mixed with a plastic thinner (107) and form a suspension (110), preferably at a temperature greater than or equal to the ambient temperature and less than the temp- temperature of the fusion of said plastic fraction, and said plastic fraction in suspension form (110) is introduced into the first reactor hydroconversion.

11. A method according to claim 7, wherein, in step (a), the fraction plastic in the form of solid particles is pre-mixed with a plastic thinner (107) and with the first supported catalyst porous hydroconversion in a distribution and mixing box (14) to form a suspension (112), then said suspension (112) is introduced into the first hydroconversion reactor via the means of injecting the catalyst into said first hydroconversion reactor.

12. | Method according to any one of the preceding claims, in in which the load comprises between 5% and 30% by weight, preferably between 5% and 20% by weight of said plastic fraction, and between 70% and 95% by weight, preferably between 80% and 95% by weight, of said fraction heavy with hydrocarbons.

13. A method according to any one of the preceding claims, comprising the separation step (c) separating a part, or the whole, of the first hydroconverted effluent (105) from step (b) to produce at least the heavy cup boiling mostly at a temperature greater than or equal to 350°C, and comprising the second step hydroconversion (d) of said heavy cut.

14. | Method according to any one of the preceding claims, in which the first section hydroconversion reactor(s) hydroconversion (20) in step (b), and optionally in step hydroconversion (d) reactors are bubbling hybrid bed reactors trained, said process further comprising an introduction step of a catalyst precursor (104), preferably 2-ethylhexanoate of molybdenum, before the injection of said charge into said at least at minus a first bubbling-driven hybrid bed reactor of the first hydroconversion section (20), such that a ca- colloidal or molecular alysator, preferably containing disulfide of molybdenum, formed when said charge reacts with sulfur.

15. A process according to any one of the preceding claims, in which the first hydroconversion catalyst, and optionally the the second hydroconversion catalyst, contains at least one metal from group VIII non-noble chosen from nickel and cobalt, preferably nickel, and at least one metal from group VIB chosen from the molybdenum and tungsten, preferably molybdenum, and comprising an amorphous support, preferably alumina.