Sulfur-promoted hydroconversion of plastic feedstocks in presence of silica-alumina bifunctional catalyst

Abstract

The present invention relates to a process for the hydroconversion of a plastic feedstock, comprising: (a1) a step of non-catalytic hydroconversion of said feedstock in the presence of hydrogen in contact with a source of free radicals comprising sulfur and introduced such that the sulfur content is from 3% to 20% by weight of the feedstock, to produce a first conversion product; (a2) a step of catalytic hydroconversion of the first conversion product in the presence of hydrogen in contact with at least one hydroconversion catalyst comprising at least one hydrodehydrogenating element and a porous non-zeolitic support comprising at least one amorphous silica-alumina, the hydrogenation dehydrogenation element is selected from non-noble metal elements of Group VIB and Group VIII of the periodic table, excluding iron, alone or as a mixture, the steps (a1) and (a2) being carried out under conditions of an absolute pressure of 1 MPa to 38 MPa, a temperature of 200 DEG C to 550 DEG C, an hourly space velocity of 0.05 h <-1 > to 10 h <-1 > per volume of the hydroconversion reactor, and a hydrogen amount of 50 Sm3 / m3 to 5000 Sm3 / m3.

Description

Field of the Invention

[0001] The present invention relates to the field of converting solid plastic raw materials into upgradable hydrocarbon mixtures, in particular the conversion of such raw materials under high pressure and high temperature in the presence of hydrogen and a hydrocracking catalyst. Prior Art

[0002] In the context of the circular economy and waste reduction, particular attention is paid to plastics (traditionally products derived from petroleum) in order to upgrade them.

[0003] The recycling of plastic waste can include the conversion of said plastics by mechanical and / or chemical means so that plastics or plastic-based objects can be produced again. This is the recycling of plastic waste.

[0004] The upgrading of plastic waste can also follow an energy upgrading path, especially for non-recyclable or difficult-to-recycle plastic waste, in some cases as an alternative to landfilling. Generally, the energy upgrading of plastic waste involves generating energy in the form of electricity and / or heat. For example, it is known to carry out a pyrolysis step on plastics from collection and sorting channels to produce, in particular, plastic pyrolysis oil, which is generally incinerated to generate electricity and / or used as fuel for industrial or district heating boilers.

[0005] Plastic waste can also be converted into hydrocarbon fractions by a hydroconversion process under high hydrogen pressure, and the hydrocarbon fractions can be particularly upgraded to fuels, such as the production of gasoline or diesel fuel, or used as raw materials for petrochemical products.

[0006] Thus, French patent application No. 21 / 14,037 registered by the applicant company relates to adding a plastic fraction (usually from waste) to a fossil heavy hydrocarbon raw material in a fluidized bed or mixed fluidized-entrained bed hydroconversion process to produce fuel bases and other upgradable hydrocarbons. The plastic fraction is initially solid and is introduced into the hydroconversion reactor in different ways, and the method shows a total conversion level close to that obtained using the same type of method to process more traditional heavy raw materials (100% fossil origin).

[0007] More generally, since the 1990s, the liquefaction of plastic waste by thermal cracking or acid-catalyzed cracking to produce fuels has been the subject of laboratory research.

[0008] The comprehensive review published by Munir et al. in 2018 (Munir et al., Renewable and Sustainable Energy Reviews, 90, 2018, 490 - 515) summarized the prior art on the hydrocracking of plastics by direct liquefaction without co - feeding. The authors concluded that an increase in reaction temperature led to an increase in conversion but also an increase in the production of undesirable gases and coke. The authors recommended a temperature not exceeding 400 °C in the presence of a catalyst. The authors also pointed out that bifunctional catalysts with hydrogenation - dehydrogenation and cracking capabilities were most suitable for plastic cracking.

[0009] Among the studies listed in the review by Munir et al. (2018), some studies demonstrated the potential of using sulfur to promote plastic conversion.

[0010] For example, Nakamura and Fujimoto (Development of New Disposable Catalyst for Waste Plastics Treatment for High Quality Transportation Fuel, Catalysis Today, 27, 1996, pp. 175 - 179) studied the conversion of polypropylene (PP) in an autoclave reactor at 380 °C to 400 °C, at an initial hydrogen pressure of 3 MPa, in the presence or absence of an iron - based catalyst supported on activated carbon or amorphous silica - alumina, and in the presence of carbon disulfide (CS 2 ). The authors observed that the presence of CS 2 increased the yield of liquid products and decreased the yield of solid residues, whether or not a catalyst was present. The authors concluded that sulfur in the reactor was a promoter for PP conversion and proposed an explanatory mechanism of the formation of hydrocarbon radicals by thermal cracking of the C - C bonds of the polymer; in the absence of H 2 S, most of these radicals recombined with each other, while in the presence of H 2 S, H 2 S diffused into the structure of the polymer, and the hydrogen atoms of H 2 S could be captured by hydrocarbon radicals, thus forming stable hydrocarbons and HS· radicals. Therefore, the lifetime of hydrocarbon radicals was shortened, preventing their recombination, and the possibility of their continued thermal cracking, which usually led to an unfavorable gas yield, was also reduced. Thus, thermal cracking could convert large polymer molecules into long molecules, which, because of H 2The stabilization of radicals by S without excessive cleavage. These long molecules can then be selectively catalytically cleaved. This is because the yields of the various fractions vary depending on the catalyst used, especially the yield of the gaseous product, which remains particularly high when using the test catalyst based on iron supported on amorphous silica-alumina, and even higher when combined with CS 2 The yield of the gaseous product is even higher when combined with CS.

[0011] Ibrahim and Seehra (Ibrahim and Seehra, Energy & Fuels, 11, 1997, 926 - 930) studied the depolymerization temperature (DT) of plastic mixtures monitored by electron spin resonance (ESR) at an initial hydrogen pressure of 500 psig (3.45 MPa). A plastic sample composed of 5% PP, 95% high-density polyethylene (HDPE), and trace (<3%) polyethylene terephthalate (PET) was mixed with other compounds: elemental sulfur, or a mixture of elemental sulfur (S) and NiMo / Al 2 O 3 catalyst, or HSZSM-5 zeolite. The authors found that when the plastic was mixed with elemental sulfur, the DT of the plastic sample decreased by 80 °C, but was not affected by the presence of HSZSM-5. Increasing the amount of elemental sulfur S introduced did not change the DT. The authors concluded that sulfur in the reactor was a promoter for the conversion of plastic through a radical mechanism during thermal cracking. No information on the conversion of plastic to fuel was provided in their study.

[0012] Shiro et al. (Shiro et al., Energy & Fuels, 16, 5, 2002, 1314 - 1320) studied the decomposition of low-density polyethylene (LDPE) in an autoclave reactor at an initial hydrogen pressure of 5 MPa and temperatures from 300 °C to 425 °C. Sulfur compounds such as H 2 S, elemental sulfur, dimethyl disulfide (DMDS, molecular formula (CH 3 S) 2 )) etc. were added. The authors concluded that the addition of sulfur compounds promoted the decomposition of LDPE.

[0013] In contrast, in hydroconversion processes, it is known that adding sulfur or sulfur compounds sulfides the catalyst, thereby "activating" it. Conventionally, the catalyst is advantageously sulfided such that at least part of the metal entities are converted to the sulfide form before contact with the feedstock to be treated. This activation treatment by sulfidation is well known to those skilled in the art.

[0014] The formation of the active phase of the catalyst by sulfidation can be carried out in situ, i.e., in a hydroconversion process, after loading the catalyst or catalyst precursor, usually in a reactor, for example, by adding organic sulfur molecules (such as DMDS, thioacetamide, etc.) to the hydrocarbon feedstock to be treated under hydrogen pressure and temperature conditions, or it can also be carried out ex situ, i.e., before loading the catalyst in a certain step of the hydroconversion process, under conditions suitable for activation.

[0015] For example, in the field of the conversion of plastic-containing feedstocks, the French patent application with the application number 21 / 14.037 mentioned above describes the possibility of forming and in situ activating a colloidal or molecular catalyst, which is an extremely small (e.g., with a size less than 1 μm) dispersed catalyst (also called an entrained catalyst or slurry), through the interaction of sulfur with a soluble catalyst precursor (usually at high temperature), thereby forming a catalyst of the metal sulfide type. The sulfur source can be H 2 S dissolved in the fossil hydrocarbon feedstock, or H 2 S contained in the hydrogen recycled to the hydroconversion reactor, or organic sulfur molecules (e.g., injecting DMDS or thioacetamide) derived from the fossil hydrocarbon fractions introduced into the feedstock to be treated.

[0016] The patent application CA2171803 relates to the liquefaction of plastic waste mixed with a suspending agent in a container under H 2 or N 2 pressure (alone or as a mixture), and optionally in the presence of a solid catalyst, and it describes the possibility of adding a sulfur donor agent to sulfide metals that may be used as catalysts, especially iron.

[0017] Due to the fact that plastic waste management and environmental issues have become more prominent than ever, there has been a continuous search for effective methods to convert plastic waste into fuels, which are particularly energy-saving and cost-reducing, and can meet various or changing product requirements, especially the greater demand for kerosene in the aviation field. This is because the demand for such fuels is expected to increase significantly in the future, which is not conducive to the traditional fuels used in the automotive industry, as the automotive industry is widely turning to vehicle electrification.

[0018] Object and Summary of the Invention

[0019] Against this background, an object of the present invention is to provide a method for converting plastics into a reformable hydrocarbon mixture in the presence of hydrogen, which can maximize the conversion rate of plastics, minimize the energy required for conversion and the gases generated during the conversion process, and at the same time maximize the yield of the kerosene fraction compared to heavier fractions.

[0020] Therefore, according to a first aspect, the present invention provides a hydroconversion method for a plastic feedstock, comprising the following steps:

[0021] (a1) A step of non-catalytic hydroconversion of the raw material by contacting it with a radical source in the presence of hydrogen, the radical source containing sulfur and being introduced such that the sulfur content is 3 wt% to 20 wt% relative to the weight of the plastic raw material to produce a first conversion product;

[0022] (a2) A step of catalytic hydroconversion of the first conversion product by contacting it with at least one hydroconversion catalyst in the presence of hydrogen, the hydroconversion catalyst containing at least one hydrodehydrogenation element selected from non-noble metal elements (alone or as a mixture, excluding iron) of Groups VIB and VIII of the Periodic Table of the Elements, and a porous non-zeolite support containing at least one amorphous silica-alumina;

[0023] The steps (a1) and (a2) are carried out under conditions of an absolute pressure of 1 MPa to 38 MPa, a temperature of 200 °C to 550 °C, a space velocity of 0.05 h -1 to 10 h -1 、hydrogen quantity of 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 .

[0024] Compared with other technologies for plastic conversion, especially pyrolysis, the method according to the present invention has the following advantages: Since its operating temperature is lower than that of pyrolysis, it is more economical especially in terms of energy, operation and capital costs.

[0025] According to one or more embodiments of the present invention, steps (a1) and (a2) are carried out in the same reactor.

[0026] According to one or more embodiments of the present invention, steps (a1) and (a2) are carried out in the same fluidized bed reactor.

[0027] According to one or more embodiments of the present invention, steps (a1) and (a2) are carried out in two independent reactors, preferably steps (a1) and (a2) are carried out in two independent fluidized bed reactors, or step (a1) is carried out in a fluidized bed reactor and step (a2) is carried out in a fixed bed reactor.

[0028] According to one or more embodiments of the present invention, the at least one amorphous silica-alumina contains a silica content of 5 wt% to 95 wt%, preferably 10 wt% to 70 wt% by weight.

[0029] According to one or more embodiments of the present invention, the hydroconversion catalyst contains:

[0030] - 0.1 wt% to 99.8 wt% of amorphous silica-alumina, relative to the total weight of the catalyst;

[0031] - 0.1 wt% to 50 wt% of said at least one hydrodehydrogenation element composed of non-noble metal elements of Groups VIB and VIII (except iron), expressed as the weight of the oxide, relative to the total weight of the catalyst;

[0032] - 0 wt% to 99.8 wt% of a porous mineral matrix, expressed as the weight of the oxide, relative to the total weight of the catalyst;

[0033] - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one element selected from phosphorus, boron, and silicon, expressed as the weight of the oxide, relative to the total weight of the catalyst;

[0034] - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one Group VIIA element;

[0035] - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one Group VIIB element,

[0036] - 0 wt% to 60 wt%, preferably 0.1 wt% to 60 wt% of at least one Group VB element;

[0037] The percentages are expressed as weight percentages, and relative to the total weight of the catalyst, the sum of the percentages of the elements constituting the catalyst is equal to 100%.

[0038] According to one or more embodiments of the present invention, the hydroconversion catalyst comprises a porous mineral matrix, which is composed of at least one high-melting-point oxide selected from alumina, clay, titanium oxide, boron oxide, and zirconium oxide (alone or as a mixture), and preferably the porous mineral matrix is alumina.

[0039] According to one or more embodiments of the present invention, the hydroconversion catalyst comprises 0.1% to 99.8% of said porous mineral matrix.

[0040] According to one or more embodiments of the present invention, the hydroconversion catalyst comprises at least one non-noble metal of Group VIII selected from nickel and cobalt, preferably nickel, and at least one metal of Group VIB selected from molybdenum and tungsten as the hydrodehydrogenation element.

[0041] According to one or more embodiments of the present invention, the sulfur content in step (a1) is 3 wt% to 15 wt%, preferably 3 wt% to 10 wt% of the plastic raw material, relative to the weight of the plastic raw material.

[0042] According to one or more embodiments of the present invention, the sulfur-containing free radical source is selected from H 2 S, elemental sulfur, carbon disulfide (CS 2 ), dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), diethyl sulfide (DES), dimethyl disulfide (DMDS, molecular formula (CH 3 S) 2 ), thiols and polysulfides, such as di-tert-nonyl polysulfide, alone or as a mixture, and preferably selected from H 2 S, DMS, DMDS and DES.

[0043] According to one or more embodiments of the present invention, the method further comprises:

[0044] (a0) A preliminary step of conditioning the feedstock to introduce it into the reactor, in which at least the first step (a1) is carried out, and the step (a0) comprises:

[0045] - Feeding the plastic feedstock in the form of solid particles into an extruder, preferably together with a plastic diluent, gradually heating it in the extruder to a temperature above the melting point of the plastic feedstock, and subjecting it to the pressure of the first hydroconversion reactor during transportation, and

[0046] - Introducing the extruded plastic feedstock into the reactor.

[0047] According to one or more embodiments of the present invention, the plastic feedstock is in solid form and contains one or more polymers selected from olefin polymers, diene polymers, vinyl polymers and styrene polymers, polyesters and polyamides, and preferably, the plastic feedstock contains at least 50% by weight of polyolefin relative to the total weight of the plastic feedstock, and the polyolefin is preferably selected from polyethylene, polypropylene and / or copolymers of ethylene and propylene.

[0048] According to one or more embodiments of the present invention, steps (a1) and (a2) are carried out at an absolute pressure of 2 MPa to 25 MPa and a temperature of 300 °C to 480 °C.

[0049] By reading the following description of specific exemplary embodiments of the present invention given by way of non-limiting examples, other subjects and advantages of the present invention will become apparent. Detailed Description of the Invention

[0051] In the following detailed description, many specific details are disclosed to understand the method more deeply. However, those skilled in the art will understand that the method can be carried out without all these specific details. In other cases, well-known features are not described in detail to avoid unnecessarily complicating the description.

[0052] The following definitions are given to better understand the present invention.

[0053] In this specification, the terms "comprising", "including" and "containing" are synonymous (have the same meaning), are inclusive or open-ended, and do not exclude other elements not mentioned. It should be understood that the term "comprising" includes the exclusive and closed term "consisting of".

[0054] In this specification, the expression "from... to..." means that the limits of the interval are included within the described value range, unless otherwise specified.

[0055] In the present invention, different numerical ranges of a given parameter 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 numerical range of a compound or element can be combined with a more preferred numerical range of another compound or element.

[0056] Within the meaning of the present invention, the different embodiments proposed can be used alone or in combination with each other, without any limitation on the combination.

[0057] In this specification, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, edited by D.R. 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, while Group VIB corresponds to the metals in column 6.

[0058] The term "hydroconversion" refers to a process whose main purpose is to reduce the boiling point range of a hydrocarbon feedstock, where most of the feedstock is converted into products with a boiling point range lower than that of the starting material. Hydroconversion typically involves the splitting of larger molecules (usually hydrocarbons) to produce smaller molecular fragments with a lower number of carbon atoms and a higher hydrogen-to-carbon ratio H / C. The reactions carried out during hydroconversion can reduce the size of hydrocarbon molecules, mainly by cleaving carbon-carbon bonds in the presence of hydrogen to saturate the broken bonds and aromatic rings. The mechanism by which hydroconversion occurs usually involves the formation of free radicals (usually hydrocarbons) during the splitting process, mainly through thermal cracking, and then capping the ends or fragments of the free radicals with hydrogen in the presence of active catalyst sites. Of course, during hydroconversion, other reactions typically associated with hydrotreating can occur, such as especially the removal of sulfur or nitrogen from the feedstock, or the saturation of olefins, as more broadly defined below. In French terminology, the term "hydroconversion" is more suitable for processes dealing with heavy petroleum feedstocks, such as atmospheric residues and vacuum residues (but not limited to these), while the term "hydrocracking" is more suitable for processes dealing with lighter feedstocks, such as vacuum gas oils and gas oils. In English terminology, the terms "hydroconversion" and "hydrocracking" are often used interchangeably. In this specification, the terms "hydrocracking" and "hydroconversion" are synonyms, and the feedstock being processed is of the plastic type.

[0059] The term "hydrotreating", commonly referred to as "HDT", refers to a milder operation whose main purpose is to remove impurities from a feedstock, such as sulfur, nitrogen, oxygen, halides, and trace metals, and to saturate olefins and / or stabilize free radicals (usually hydrocarbons), by reacting them with hydrogen rather than allowing them to react with themselves. The main purpose is not to change the boiling point range of the feedstock. Thus, hydrotreating particularly includes hydrodesulfurization (commonly referred to as "HDS") reactions, hydrodenitrogenation (commonly referred to as "HDN") reactions, and hydrodemetallization (commonly referred to as "HDM") reactions, and is accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, or hydrodeasphalting reactions, as well as a reduction in Conradson carbon residue. Hydrotreating is typically carried out in a fixed-bed reactor, although other reactors can also be used for hydrotreating, such as ebullated-bed hydrotreating reactors.

[0060] The terms "porous supported catalyst", "solid supported catalyst" and "supported catalyst" refer to catalysts commonly used in conventional fluidized bed and fixed bed hydroconversion systems, including catalysts mainly designed for hydrocracking or hydrodemetallization and catalysts mainly designed for hydrotreating. Such catalysts typically comprise (i) a catalyst support having a large surface area and a large number of interconnected channels or pores and (ii) fine particles of an active catalyst dispersed in the pores, such as sulfides of cobalt, nickel, tungsten or molybdenum, or mixed sulfides of these elements (e.g., NiMo, CoMo, etc.). Supported catalysts are typically produced in the form of cylindrical extrudates (pellets) or spherical solids, but other forms are possible.

[0061] In this specification, in accordance with IUPAC convention, the term "micropore" should be understood to mean a pore with a diameter less than 2 nm; the term "mesopore" should be understood to mean a pore with a diameter from 2 nm to 50 nm, and the term "macropore" should be understood to mean a pore with a diameter greater than 50 nm.

[0062] The term "specific surface area" of a support or catalyst should be understood to mean the BET specific surface area determined by nitrogen adsorption in accordance with standard ASTM D3663-78, developed according to the Brunauer-Emmett-Teller method described in the journal "The Journal of the American Chemical Society", 60, 309 (1938).

[0063] Quantitative analysis of microporosity (pore diameter less than 2 nm) is carried out using the "t" method (Lippens-De Boer method, 1965), which corresponds to the transformation of the initial nitrogen adsorption isotherm, as described in the publication "Adsorption by Powders and Porous Solids. Principles, Methodology and Applications" by F. Rouquérol, J. Rouquérol and K. Sing, Academic Press, 1999.

[0064] Similarly, the volume of mesopores is determined by nitrogen porosimetry, as described in the publication "Adsorption by Powders and Porous Solids. Principles, Methodology and Applications" by F. Rouquérol, J. Rouquérol and K. Sing, Academic Press, 1999.

[0065] The term "total pore volume measured by nitrogen porosimetry" for the support and the catalyst shall be understood to mean the volume measured by nitrogen adsorption for P / P 0 = 0.99, at which pressure nitrogen is considered to have filled all the pores.

[0066] The term "total pore volume measured by mercury porosimetry" for the support and the catalyst shall be understood to mean the volume measured by mercury intrusion porosimetry in accordance with standard ASTM D4284 - 83, at a maximum pressure of 4000 bar (400 MPa), a surface tension of 485 dynes / cm, and a contact angle of 140°. In accordance with the recommendations on pages 1050 - 1055 of the publication "Techniques de l'ingénieur, traité analyse et caractérisation" [Techniques of the Engineer, Analysis and Characterization Treatise] written by Jean Charpin and Bernard Rasneur, the wetting angle is taken as 140°. The value at which mercury fills all the intergranular voids and higher values are set at 0.2 MPa, and it is considered that above this value, mercury penetrates into the pores of the sample. For better accuracy, the pore volume value corresponds to the pore volume value measured by mercury intrusion porosimetry on the sample minus the pore volume value measured by mercury intrusion porosimetry on the same sample at a pressure of 0.2 MPa.

[0067] The method according to the present invention and its operation are described in more detail below.

[0068] The object of the present invention is to provide a method for the hydroconversion of plastic raw materials, comprising the following steps:

[0069] (a1) A step of non - catalytic hydroconversion of the raw material by contacting it with a radical source in the presence of hydrogen, the radical source containing sulfur and being introduced such that the sulfur content is from 3% to 20% by weight relative to the weight of the plastic raw material, to produce a first conversion product;

[0070] (a2) A step of catalytic hydroconversion of the first conversion product by contacting it with at least one hydroconversion catalyst in the presence of hydrogen, the hydroconversion catalyst comprising at least one hydro - dehydrogenation element selected from the non - noble metal elements of groups VIB and VIII of the periodic table, alone or as a mixture, and a porous non - zeolite support comprising a porous mineral matrix and at least one zeolite,

[0071] Steps (a1) and (a2) are carried out at an absolute pressure of 1 MPa to 38 MPa, a temperature of 200 °C to 550 °C, and a space velocity per hydroconversion reactor of 0.05 h -1 to 10 h-1 、Under the condition that the hydrogen gas amount is 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 .

[0072] The feedstock

[0073] The feedstock processed by the hydroconversion method according to the present invention is a plastic feedstock.

[0074] The plastic feedstock of the method according to the present invention contains plastics. More specifically, the plastics themselves contain polymers.

[0075] Plastics or plastic materials are generally polymers, which are usually mixed with additives for the purpose of forming various materials and objects (injection molded parts, pipes, films, fibers, fabrics, fillers, coatings, etc.) after molding. The additives used in plastics can be organic compounds or inorganic compounds. For example, they are fillers, dyes, pigments, plasticizers, property modifiers, flame retardants, etc.

[0076] Therefore, the term "plastic feedstock" should be understood as the solid feedstock of plastics, which contains one or more polymers and may contain other compounds, such as additives and / or common impurities of organic or inorganic origin, especially impurities generated by the life cycle of plastic materials and products, and / or impurities generated by waste collection and sorting circuits. For example, common impurities can be metals, organic substances or minerals; they can be packaging residues, food residues or compostable residues (biomass). Common impurities can also include glass, wood, cardboard, paper, aluminum, iron, metal, tires, rubber, silicone, hard polymers, thermosetting polymers, household, chemical or cosmetic, waste oil, water.

[0077] In this specification, the term "impurities in plastics" refers to all the following compounds initially contained in the plastic feedstock that are not polymers and cannot be converted in one or more steps of the method. For example, some organic additives can be at least partially converted in the method of the present invention in the same way as polymers. Therefore, these are not regarded as impurities in plastics. On the other hand, some inorganic additives can be removed during the process of the method, such as additives containing metals, and / or sulfur, and / or nitrogen, and / or oxygen, and / or other heteroatoms (Cl, Br, etc.). They are regarded as impurities in plastics themselves.

[0078] The plastics contained in the plastic feedstock of the feedstock of the method of the present invention are usually production wastes and / or waste materials, especially household wastes, construction wastes or wastes of electrical and electronic equipment. Preferably, the plastic waste comes from collection and sorting channels.

[0079] Thus, the plastic raw material of the method of the present invention comprises a polymer, especially a thermoplastic. The polymer comprised in the plastic raw material may be an olefin polymer, a diene polymer, a vinyl polymer, a styrene polymer (e.g., polystyrene "PS"), a polyester and / or a polyamide.

[0080] Preferably, the polymer comprised in the plastic raw material of the present invention is an olefin polymer, a diene polymer, a vinyl polymer and / or a styrene polymer (e.g., polystyrene "PS"). Preferably, the polymer comprised in the plastic raw material is a polyolefin (olefin polymer), such as polyethylene (PE), polypropylene (PP) and / or a copolymer of ethylene and propylene.

[0081] For example, the plastic raw material of the feedstock comprises at least 50% by weight, preferably at least 80% by weight, preferably at least 90% by weight, very preferably at least 94% by weight of polyolefin relative to the total weight of the plastic raw material.

[0082] The plastic raw material may comprise a polymer mixture, especially a thermoplastic mixture and / or a mixture of a thermoplastic and other polymers, and compounds other than these thermoplastics and polymers, especially additives advantageously used for formulating plastic materials and common impurities usually originating from the life cycle of plastic materials and objects and / or from waste collection and sorting channels. The plastic raw material of the method of the present invention usually comprises less than 50% by weight, preferably less than 20% by weight, and preferably less than 10% by weight of these additives and common impurities.

[0083] The plastic raw material may be advantageously pretreated upstream of the method in order to remove at least all or part of the "coarse" common impurities, i.e., common impurities in the form of particles having a size greater than or equal to 10 mm, preferably greater than or equal to 5 mm, even greater than or equal to 1 mm, such as common impurities of the types of wood, paper, biomass, iron, aluminum, glass, etc., and to make it into a usually particulate form (dispersed solid) for ease of handling in the method. This pretreatment may include a grinding step, an atmospheric pressure washing step and / or a drying step. This pretreatment may be carried out at different locations, such as at a waste collection and sorting center, or at the same location where the treatment method according to the present invention is carried out. Preferably, this pretreatment may reduce the content of common impurities to less than 6% by weight. After the pretreatment is completed, the plastic raw material is usually stored in particulate form, such as in the form of ground material or powder, for ease of handling and transportation to the method.

[0084] (a0) Optional step of conditioning the feedstock to inject it into the first hydroconversion reactor

[0085] The method according to the present invention may include step (a0) of conditioning the plastic raw material to inject it into the first hydroconversion reactor.

[0086] In this specification, the term "first hydroconversion reactor" refers to a reactor that at least performs step (a1), that is, a reactor that performs step (a1), or if both steps (a1) and (a2) are performed in the same reactor, a reactor that performs both of these steps. Therefore, if the two steps are performed in separate reactors, the hydroconversion reactor for step (a2) is not the first hydroconversion reactor.

[0087] The term "conditioning of the feedstock" should be understood to mean the conditioning carried out for step (a1), which is followed by the hydroconversion of the feedstock after introducing the feedstock into the first hydroconversion reactor, that is, placing the feedstock in a state suitable for hydroconversion in the first hydroconversion reactor and under temperature and pressure conditions.

[0088] The plastic feedstock initially in solid form can be conditioned before being fed into the first hydroconversion reactor, especially to adapt to the type of hydroconversion reactor used and to facilitate its conversion.

[0089] According to one or more embodiments, the plastic feedstock in the form of solid particles is fed into an extruder, preferably together with a plastic diluent, and is gradually heated in the extruder to a temperature above the melting point of the plastic feedstock and is placed under the pressure of the first hydroconversion reactor during transportation, with the transportation time preferably less than 15 minutes, and the extruded plastic feedstock is introduced into the reactor.

[0090] According to these embodiments, the plastic feedstock introduced into the first hydroconversion reactor by extrusion is substantially in liquid form.

[0091] Extrusion is generally a method that enables a polymer initially provided in a solid state to be injected or molded. According to the extrusion method, the material is transported, kneaded, and heated by one or more screws, so that it can be melted. At the same time, one or more screws transport the material and increase its pressure, so that it can be injected into a die or mold.

[0092] According to these embodiments of the present invention, extruding the plastic feedstock is a way to introduce a plastic feedstock that is solid at ambient temperature into the first hydroconversion reactor operating at high pressure and high temperature. Therefore, extrusion enables the plastic feedstock to be heated to liquefy it and pressurize the plastic feedstock to the operating conditions of the reactor described below.

[0093] The material is not injected into a die or mold as in a traditional extrusion method, so it does not constitute a molding method, but is directly injected into the reactor.

[0094] The "plastic diluent" is preferably formed from light liquid hydrocarbons or a mixture of light liquid hydrocarbons. For example, the plastic diluent is a hydrocarbon oil composed of hydrocarbons, and at least 50% by weight, preferably at least 80% by weight, of the total weight of the plastic diluent has a boiling point below 300 °C. Examples of suitable hydrocarbon diluents include, but are not limited to, light liquid hydrocarbons, typically C5+ hydrocarbons, i.e., hydrocarbons that can have 5 and more carbon atoms per molecule, such as xylene, toluene, gasoline, mixtures thereof, etc. The plastic diluent can function as a solvent for the plastic raw material, particularly as a solvent for one or more polymers of the plastic raw material.

[0095] During the extrusion process, the plastic raw material is preferably gradually heated to a temperature above its melting point in order to melt. Advantageously, at the end of the extrusion, at least 80% by weight, very advantageously at least 90% by weight, preferably at least 95% by weight, even 98% by weight of the plastic raw material is in liquid form (melted). As described above, the plastic raw material usually contains compounds other than polymers, particularly plastic impurities. Some of these non-polymeric compounds, including plastic impurities, may not dissolve and / or have a melting point higher than one or more polymers of the plastic raw material. Even if all of the one or more polymers are melted, a part of the liquid raw material may still remain in solid form considering the non-polymeric compounds. This is the case for all the steps described below, in which heating causes the plastic raw material to liquefy completely or almost completely.

[0096] The extrusion temperature depends on the composition of one or more polymers of the plastic raw material (the nature and proportion of one or more polymers).

[0097] Preferably, the extruder operates at a temperature 25 °C lower than the melting point of the plastic raw material to a temperature 25 °C higher than the melting point of the plastic raw material.

[0098] When the plastic raw material contains a polymer mixture, the extruder operates at a temperature 25 °C lower than the melting point of the most fusible polymer (i.e., the polymer with the lowest melting point) in the plastic raw material to a temperature 25 °C higher than the melting point of the least fusible polymer (i.e., the polymer with the highest melting point) in the plastic raw material.

[0099] Advantageously, the plastic raw material is preferably gradually heated in the extruder to a temperature above the melting point of the polymer with the highest melting point.

[0100] For example, the melting point of polypropylene (PP) is about 170 °C, the melting point of polyethylene (PE) is about 85 °C to 140 °C, and the melting point of polystyrene (PS) is about 240 °C to 270 °C.

[0101] Preferably, the extruder operates at a temperature of 60 °C to 295 °C, more preferably at a temperature of 60 °C to 195 °C.

[0102] Advantageously, the extruder operates at a temperature of 60 °C to 165 °C to melt a plastic feedstock that mainly contains PE as a polymer.

[0103] Advantageously, the extruder operates at a temperature of 145 °C to 195 °C to melt a plastic feedstock that mainly contains PP as a polymer.

[0104] Advantageously, the extruder operates at a temperature of 215 °C to 295 °C to melt a plastic feedstock that mainly contains PS as a polymer.

[0105] Advantageously, the operating temperature of the extruder is adjusted according to the composition of the plastic feedstock.

[0106] Advantageously, the extruder includes at least one screw conveying section, called the extrusion section, which is fed with the plastic feedstock.

[0107] The residence time in the extrusion section (the volume of the section divided by the volumetric flow rate of the plastic feedstock) is advantageously less than 15 minutes, preferably less than 10 minutes, and more preferably less than 2 minutes.

[0108] The extrusion section is advantageously connected to a vacuum extraction system to remove impurities that may be present in the plastic feedstock, such as dissolved gases, light organic compounds, and / or moisture.

[0109] The extrusion section may also advantageously include a filtration system for removing solid particles of undesired size, such as particles larger than 200 μm and preferably larger than 40 μm, such as sand grains. If a diluent is used and the viscosity can be reduced, smaller-sized particles, such as particles larger than 3 μm, can be filtered.

[0110] According to one or more other embodiments, the plastic feedstock in solid particle form is mixed with a plastic diluent in a mixing section and heated in a heating section to a temperature above the melting point of the plastic feedstock, preferably 60 °C to 295 °C, and then introduced into the first hydroconversion reactor. The heating step can be carried out before or after mixing with the plastic diluent, preferably after mixing with the plastic diluent.

[0111] Thus, these embodiments correspond to mixing the plastic feedstock with the plastic diluent to form a slurry, subsequently heating to obtain a substantially liquid plastic feedstock, and then directly injecting the substantially liquid-form plastic feedstock.

[0112] The term "plastic raw material in substantially liquid form" should be understood to mean that at least 80% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, and even more preferably at least 98% by weight of one or more polymers of the plastic raw material are in liquid form. The term "polymer of plastic raw material in liquid form" should be understood to mean a polymer that is not in solid form, and the solid form is generally considered to correspond to the crystalline, semi-crystalline, and amorphous states of the polymer.

[0113] The term "slurry" should be understood to mean a mixture of substances in suspension form, which generally corresponds to a system formed by solid particles dispersed in a liquid (liquid dispersion). More specifically, a plastic raw material in suspension form corresponds to a system containing solid plastic particles dispersed in a liquid, such as a system containing 1% to 50% by weight, even 1% to 30% by weight, or 5% to 20% by weight of solid plastic particles dispersed in a liquid. The continuous liquid phase in which the solid plastic particles are dispersed can be a diluent.

[0114] These embodiments particularly have the advantage of using simple and inexpensive equipment.

[0115] The plastic raw material in solid particle form can be pre-mixed with a plastic diluent in a mixing section to form a suspension; then the suspension can be sent to a heating section to be heated to a temperature above the melting point of the plastic raw material, so that the solid particles of the suspended plastic raw material melt, and subsequently the heated plastic raw material can be introduced into the first hydroconversion reactor. The mixing of the plastic diluent and the plastic raw material in particle form in the mixing section is preferably carried out at atmospheric pressure or a pressure close to atmospheric pressure.

[0116] Preferably, during the mixing step in the mixing section, the temperature is such that the suspension exhibits a kinematic viscosity of less than 0.3x10 -3 m 2 / s, corresponding to the viscosity of a pumpable fluid. In the case where the mixing step is separated and before the heating step, the temperature of this step is preferably lower than the operating temperature in the following heating step.

[0117] The mixing section can include a mixing tank, which includes dynamic stirring devices for suspension, such as agitators and / or recirculation pumps.

[0118] After the heating of the suspension is completed, the plastic raw material is substantially in liquid form.

[0119] The temperature conditions of the extruders of other embodiments described above are applicable to the heating of the suspension, and thus will not be repeated here.

[0120] The heating temperature can also depend on the plastic diluent used. In particular, this plastic diluent, depending on its properties, can cause the plastic raw material in suspension form to melt at a lower temperature.

[0121] The heating section includes any heating device known to those skilled in the art that can heat plastic raw materials in the form of a suspension, such as a furnace having at least one heating chamber, and / or a pipe through which the suspension flows, any type of suitable heat exchanger, etc.

[0122] The mixing section and the heating section can be formed as part of the same device, which is configured to continuously perform mixing and then heating.

[0123] Before being introduced into the first hydroconversion reactor, the heated plastic raw material can undergo a pressurization step to adapt to the operating pressure in the first hydroconversion reactor, for example, by a suitable pump. It can also undergo a filtration step, for example, for the purpose of removing solid particles that may constitute part of the impurities in the plastic raw material, such as sand, glass, metal, certain additives called fillers, etc.

[0124] According to another alternative form, the plastic raw material in substantially liquid form can be directly injected after heating the plastic raw material to obtain a substantially liquid plastic raw material and then mixing it with a plastic diluent to form a diluted plastic raw material introduced into the first hydroconversion reactor.

[0125] According to another alternative form, the mixing step and the heating step are carried out simultaneously, and the mixing section and the heating section form part of the same device, which is configured to perform mixing and heating simultaneously.

[0126] According to one or more other embodiments, the plastic raw material in the form of a suspension is directly injected into the first hydroconversion reactor: the plastic raw material in the form of solid particles is pre-fed into a mixer to be mixed with a plastic diluent and form a suspension, preferably at a temperature greater than or equal to the ambient temperature and lower than the melting point of the plastic raw material, and the plastic raw material in the form of the suspension is introduced into the first hydroconversion reactor.

[0127] These embodiments also have the advantage of using simple and inexpensive equipment.

[0128] According to these embodiments, the plastic raw material in the form of solid particles is pre-fed into a mixer to be mixed with a plastic diluent and form a suspension, and then the plastic raw material in the form of the suspension is introduced into the first hydroconversion reactor.

[0129] The mixing of the plastic diluent and the plastic raw material in the mixer is preferably carried out at a temperature greater than or equal to the ambient temperature (e.g., 15 °C) and lower than the melting point of the plastic raw material (or if the plastic raw material contains a polymer mixture, lower than the melting point of the polymer with the lowest melting point). A temperature slightly lower than the melting point of the plastic raw material may constitute the upper limit of the mixture temperature, since the plastic diluent used affects, depending on its nature, the temperature at which the plastic raw material can dissolve (in the case where the plastic diluent has a solvent function).

[0130] According to one configuration, the mixing can be carried out at a temperature greater than or equal to 50 °C or even 75 °C and less than 170 °C, e.g., very suitable for using VGO as the plastic diluent and suitable for a plastic raw material mainly containing PP as the polymer, or at a temperature greater than or equal to 150 °C and less than 170 °C, e.g., very suitable for using vacuum residue as the plastic diluent and suitable for a plastic raw material mainly containing PP as the polymer.

[0131] According to one configuration, the mixing can be carried out at a temperature greater than or equal to 50 °C or even 75 °C and less than 140 °C, or at a temperature greater than or equal to 50 °C or even 75 °C and less than 85 °C, e.g., very suitable for using VGO as the plastic diluent and suitable for a plastic raw material mainly containing PE as the polymer.

[0132] According to one configuration, the mixing can be carried out 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, e.g., very suitable for using VGO as the plastic diluent and suitable for a plastic raw material mainly containing PS as the polymer, or at a temperature greater than or equal to 150 °C and less than 270 °C, even less than 240 °C, e.g., very suitable for using vacuum residue as the plastic diluent and suitable for a plastic raw material mainly containing PS as the polymer.

[0133] The mixing can be or can not be active. Examples of active mixing devices that can be used include, but are not limited to, high-shear mixing, such as the mixing generated in a pump with a rotor agitator or a propeller, multiple static in-line mixers, a combination of multiple static in-line mixers and a high-shear in-line mixer, a combination of multiple static in-line mixers and a high-shear in-line mixer followed by recirculation pumping in a storage tank, a combination of the above devices, and then one or more multistage centrifugal pumps.

[0134] Before being introduced into the first hydroconversion reactor, the plastic raw material in suspension form can undergo a pressurization step to adapt to the operating pressure inside the first hydroconversion reactor.

[0135] (a1) Sulfur-promoted thermal conversion step

[0136] According to the invention, the process comprises a first step (a1) of non-catalytic hydroconversion of a plastic feedstock by contacting it with a radical source in the presence of hydrogen to produce a first conversion product.

[0137] The term "non-catalytic" is to be understood as meaning that the hydroconversion step (a1) is carried out without involving a catalytic reaction by means of a catalyst (i.e. a hydroconversion catalyst), such as those known to be used in conventional hydroconversion processes, which are generally porous supported catalysts or entrained catalysts, also known as slurries (catalysts of very small size, for example with a diameter of less than 1 μm, dispersed in the reaction medium, homogeneously distributed in the reactor and entrained in the product leaving the reactor), such as those formed from soluble catalyst precursors of the metal or organometallic type.

[0138] This type of catalyst (porous supported or slurry type) does not participate in the reaction in step (a1) of the process according to the invention.

[0139] The radical source contains sulfur and may be denoted in the remainder of the description by the expression "sulfur-based radical source".

[0140] The introduction of the sulfur-based radical source is such that the sulfur content (elemental sulfur S) is from 3% to 20% by weight, preferably from 3% to 15% by weight, preferably from 3% to 10% by weight, relative to the weight of the feedstock.

[0141] According to one or more embodiments of the invention, the sulfur-based radical source is selected from the non-exhaustive list of the following compounds: H 2 S, elemental S, carbon disulfide (CS 2 ), dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), diethyl sulfide (DES), dimethyl disulfide (DMDS, molecular formula (CH 3 S) 2 ), thiols or polysulfides (for example, of the general formula R 1 -S-S-R 2 or R-S-S-SH, where R, R 1 and R 2 may be H, alkyl or aryl), such as di-tert-nonyl polysulfide, alone or as a mixture. Preferably, the sulfur-based radical source is selected from H 2 S, DMS, DMDS and DES, preferably DMDS or H 2 S.

[0142] The operating conditions and those of the hydroconversion step (a2) will be described in detail below.

[0143] Without being bound by any theory, regarding H 2The free radical mechanism of S and HS· free radicals (such as those demonstrated in the prior art and described above) may at least partially explain the promotion of the conversion of the plastic raw material in step (a1) of the method according to the present invention.

[0144] During this hydroconversion step, the plastic raw material is converted the most. Specifically, the method according to the present invention can advantageously convert more than 50% by weight, preferably more than 65% by weight, more preferably more than 80% by weight, and even more preferably more than 90% by weight of the solid plastic raw material into non-solid (i.e., liquid and gas) conversion products.

[0145] The first conversion product is a hydrocarbon, which can be characterized by a boiling point range. Generally, a hydrocarbon fraction is defined as having an initial boiling point greater than or equal to a first temperature and a final boiling point lower than a second temperature, where the second temperature is higher than the first temperature. For simplicity, the expression "boiling point range from... to..." can be used to express these initial boiling points (within the range) and final boiling points (outside the range).

[0146] The first conversion product contains hydrocarbon fractions lighter than naphtha (typical boiling point range of IP to 80 °C, where IP is the starting point of the distillation curve), naphtha-type fractions (typical boiling point range of 80 °C to 150 °C), kerosene-type fractions (typical boiling point range of 150 °C to 250 °C), gas oil-type fractions (typical boiling point range of 250 °C to 370 °C), heavy fractions (typical boiling point range of 370 °C to 540 °C), very heavy fractions (typical boiling point range of 540 °C to 740 °C), and super heavy fractions (typical boiling point range higher than 740 °C).

[0147] The first conversion product may also contain a small amount of gaseous products, usually gases such as C 1 to C 6 hydrocarbons (i.e., having 1 to 6 carbon atoms).

[0148] (a2) Catalytic hydroconversion step

[0149] According to the present invention, the method includes a second step (a2) of catalytic hydroconversion of the first conversion product by contacting it with at least one hydroconversion catalyst in the presence of hydrogen.

[0150] This second catalytic hydroconversion step (a2) forms a second conversion product.

[0151] These second conversion products are mixtures of upgradable hydrocarbons, in particular hydrocarbon fractions as described below, which are characterized in particular by a boiling range as described for the first hydroconversion product. These fractions can be used as fuel bases or as feedstocks for petrochemicals (light hydrocarbons, fractions for steam crackers, in particular for the production of recycled polyolefins, bases for the production of bitumen, lubricants, etc.), especially directly after fractionation or, after fractionation, after step (a2), one or more treatments are carried out, such as hydrotreatment aimed at removing residual sulfur or other possible contaminants (such as nitrogen, chlorine, silicon or metals).

[0152] The second conversion products contain hydrocarbon fractions lighter than naphtha (typical boiling range IP to 80 °C), naphtha-type fractions (typical boiling range 80 °C to 150 °C), kerosene-type fractions (typical boiling range 150 °C to 250 °C), gas oil-type fractions (typical boiling range 250 °C to 370 °C), heavy fractions (typical boiling range 370 °C to 540 °C), very heavy fractions (typical boiling range 540 °C to 740 °C) and extra-heavy fractions (typical boiling range above 740 °C).

[0153] The second conversion products may also contain small amounts of gaseous products, usually gases, such as C 1 to C 6 hydrocarbons. Preferably, relative to the feedstock, the gas produced in step (a1) is less than 30% by weight, more preferably less than 20% by weight, even more preferably less than 15% by weight.

[0154] The combination of the sulfur-promoted first hydroconversion step (a1) without a catalyst and the catalytic hydroconversion step (a2) based in particular on an anti-sulfur and selective catalyst suitable for low-temperature operation can maximize the conversion rate of plastic feedstocks, while minimizing the energy required for conversion and minimizing gas production during conversion, in order to increase the relative yield of favorable liquid products.

[0155] This is because the inventors have demonstrated that by combining these two steps (a1) and (a2), at the end of the hydroconversion, surprisingly, the yield of gaseous hydrocarbons (i.e., C 1 to C 6 hydrocarbons) can be minimized, while maximizing the kerosene fraction (boiling range: 150 °C - 250 °C) produced relative to the heavier fractions.

[0156] Catalyst

[0157] The hydroconversion catalyst used in the process of the present invention is a bifunctional hydrocracking catalyst which combines an acid function and a hydrogenation-dehydrogenation function and an optional binder matrix.

[0158] Such catalysts are well known in the field of hydrocracking.

[0159] Such hydrocracking catalysts are generally classified according to the nature of their acidic function, in particular catalysts comprising an amorphous acidic function of the silica-alumina type and catalysts comprising a zeolite cracking function, such as zeolite Y or zeolite beta. Hydrocracking catalysts can also be classified according to the main products obtained when they are used in a hydrocracking process (in a conventional hydrocracking process treating feeds of the vacuum gas oil or gas oil type, the two main products are generally middle distillates and naphtha).

[0160] The hydroconversion catalyst used in the process of the present invention comprises at least one hydrodehydrogenation element selected from the non-noble metal elements of groups VIB and VIII of the Periodic Table of the Elements (alone or as a mixture, excluding iron), and a porous support comprising amorphous silica-alumina and optionally a porous mineral matrix, and preferably consisting thereof.

[0161] The hydroconversion catalyst used in the process of the present invention does not contain zeolite.

[0162] The hydroconversion catalyst is sulfur-resistant, at least due to the nature of one or more hydrodehydrogenation elements it contains. Thus, it can tolerate the presence of sulfur in a sulfur-based radical source, particularly in the case where steps (a1) and (a2) are carried out in the same reactor.

[0163] Depending on the choice of catalyst, the hydrotreating reaction of heteroatoms contained in the feedstock can be promoted.

[0164] The hydroconversion catalyst advantageously comprises:

[0165] - from 0.1% to 99.8% by weight of amorphous silica-alumina, relative to the total weight of the catalyst;

[0166] - from 0.1% to 40% by weight of the at least one hydrodehydrogenation element composed of non-noble metal elements of groups VIB and VIII, expressed as the weight of the oxide, excluding iron, relative to the total weight of the catalyst;

[0167] - from 0% to 99.8% by weight of a porous mineral matrix (binder), preferably from 0.1% to 99.8% by weight of a porous binding matrix, expressed as the weight of the oxide, relative to the total weight of the catalyst;

[0168] - from 0% to 20% by weight, preferably from 0.1% to 20% by weight of at least one element selected from phosphorus, boron and silicon, expressed as the weight of the oxide, (for phosphorus, expressed as the weight of the oxide P 2 O 5 and for boron, expressed as the weight of the oxide B 2 O3 in terms of weight, for silicon, as the oxide SiO 2 in terms of weight);

[0169] - from 0 wt% to 20 wt%, preferably from 0.1 wt% to 20 wt% of at least one Group VIIA element;

[0170] - from 0 wt% to 20 wt%, preferably from 0.1 wt% to 20 wt% of at least one Group VIIB element,

[0171] - from 0 wt% to 60 wt%, preferably from 0.1 wt% to 60 wt% of at least one Group VB element,

[0172] The percentages are expressed in weight percentages and, relative to the total weight of the catalyst, the sum of the percentages of the elements constituting the catalyst is equal to 100%.

[0173] Hydrodehydrogenation functional substance

[0174] The hydroconversion catalyst in step (a2) comprises at least one hydrodehydrogenation element selected from the non-noble metal elements of Groups VIB and VIII of the Periodic Table of the Elements, alone or as a mixture, except iron.

[0175] Advantageously, the hydroconversion catalyst of the process of the present invention does not contain noble metals, which may make the catalyst sensitive to certain compounds (such as sulfur compounds) and weaken its activity.

[0176] Preferably, the Group VIII non-noble metal elements are selected from cobalt and nickel, alone or as a mixture, preferably nickel.

[0177] Preferably, the Group VIB elements are selected from chromium, tungsten and molybdenum, alone or as a mixture, preferably selected from molybdenum and tungsten.

[0178] Preferred combinations of metals are: nickel-molybdenum (NiMo), nickel-molybdenum-tungsten (NiMoW) and nickel-tungsten (NiW), and very preferably nickel-molybdenum (NiMo).

[0179] The content of the Group VIII non-noble metal elements other than iron in the catalyst is advantageously from 0 wt% to 20 wt% of the oxide, preferably from 0.5 wt% to 10 wt% of the oxide, very preferably from 1.0 wt% to 8 wt% of the oxide, relative to the total weight of the catalyst.

[0180] The content of the Group VIB elements in the catalyst is advantageously from 1 wt% to 50 wt% of the oxide, preferably from 5 wt% to 40 wt% of the oxide, more preferably from 10 wt% to 35 wt% of the oxide, relative to the total weight of the catalyst.

[0181] Preferably, the hydroconversion catalyst used in the method of the present invention further contains a promoter element selected from phosphorus, boron, and silicon, and phosphorus is highly preferred.

[0182] In one or more preferred embodiments, the hydroconversion catalyst comprises nickel, molybdenum, and optionally phosphorus.

[0183] When the catalyst contains phosphorus, the phosphorus content is generally less than 15% by weight of oxide P relative to the total weight of the catalyst 2 O 5 , preferably 0.1% to 10% by weight of oxide P relative to the total weight of the catalyst 2 O 5 , preferably 0.2% to 6% by weight of oxide P 2 O 5 .

[0184] The hydroconversion catalyst may further contain at least one Group VIIA element, preferably selected from chlorine and fluorine.

[0185] The hydroconversion catalyst may further contain at least one Group VIIB element, preferably manganese.

[0186] The hydroconversion catalyst may further contain at least one Group VB element, preferably niobium.

[0187] The carrier of the catalyst

[0188] The hydroconversion catalyst in step (a2) comprises a non-zeolite porous carrier, which comprises at least one amorphous silica-alumina and optionally a porous mineral matrix different from the at least one amorphous silica-alumina, and is preferably composed of the same.

[0189] The weight content of amorphous silica-alumina in the carrier is preferably 1% to 99.9% by weight, preferably 20% to 98% by weight, preferably 40% to 96% by weight relative to the total weight of the carrier.

[0190] The weight content of silica (SiO 2 ) in the silica-alumina is preferably 5% to 95% by weight, preferably 10% to 70% by weight, preferably 15% to 60% by weight, more preferably 20% to 50% by weight.

[0191] The preparation of amorphous silica-alumina is well-known to those skilled in the art. For example, a silica-alumina gel can be obtained by the reaction of a silicon precursor with a specific aluminum precursor having selected characteristics (e.g., regarding the dispersity index, sodium content, sulfur content, etc.). The preparation of the catalyst can include the step of preparing the silica-alumina gel, and optionally mixing with a binder (such as an aluminum binder), shaping, thermal and / or hydrothermal treatment, and introducing at least one hydrodehydrogenation element in order to obtain the desired characteristics of the catalyst support and the catalyst.

[0192] The support of the hydroconversion catalyst can advantageously include the following characteristics:

[0193] - The specific surface area measured by the BET method is from 100 m 2 / g to 600 m 2 / g, preferably from 150 m 2 / g to 450 m 2 / g, more preferably from 250 m 2 / g to 400 m 2 / g.

[0194] - The total pore volume measured by nitrogen porosimetry is greater than 0.45 ml / g, preferably 0.5 ml / g to 1 ml / g, more preferably 0.6 ml / g to 0.7 ml / g.

[0195] - The total pore volume measured by mercury porosimetry is greater than 0.45 ml / g, preferably 0.5 ml / g to 1 ml / g, more preferably 0.5 ml / g to 0.75 ml / g.

[0196] The support of the hydroconversion catalyst can also contain a porous mineral matrix, also known as a binding matrix or binder, which is different from amorphous silica-alumina. More precisely, the amorphous silica-alumina of the porous support of the hydroconversion catalyst can act as a binder in addition to providing an acid function to the catalyst, and the support of the catalyst can contain another compound acting as a binder.

[0197] The adhesive matrix is different from amorphous silica-alumina and advantageously can be composed of at least one high melting point oxide, preferably selected from alumina, clay, titanium oxide, boron oxide and zirconium oxide, alone or as a mixture. Preferably, the porous mineral matrix is alumina. Advantageously, alumina can be provided in all forms known to those skilled in the art. For example, alumina is selected from α, ρ, χ, κ, η, γ, θ and δ alumina, preferably selected from γ, θ and δ alumina, more preferably γ-alumina, such as boehmite. When the carrier contains alumina, the weight content of alumina in the catalyst carrier can be 1 wt% to 70 wt%, preferably 2 wt% to 60 wt%, more preferably 5 wt% to 50 wt% relative to the total weight of the carrier.

[0198] The carrier is advantageously provided in the form of beads, extrudates, pellets or irregular and non-spherical agglomerates, and its specific shape can be obtained by a crushing step. The carrier is usually of millimeter size, preferably with a size of 0.4 mm to 4.4 mm.

[0199] The catalyst may further contain at least one organic compound containing oxygen and / or nitrogen and / or sulfur before sulfidation. Such additives are known to those skilled in the art. Generally, the organic compound is selected from compounds containing one or more chemical functional groups selected from the following or compounds containing a furan ring or sugars, and the chemical functional groups are selected from carboxylic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide functional groups.

[0200] The content of one or more organic compounds containing oxygen and / or nitrogen and / or sulfur in the catalyst is 1 wt% to 30 wt%, preferably 1.5 wt% to 25 wt%, more preferably 2 wt% to 20 wt% relative to the total weight of the catalyst.

[0201] The preparation of the catalyst is known to those skilled in the art and generally includes the step of impregnating a metal of Group VIII and / or Group VIB and optionally phosphorus and / or an organic compound on a carrier containing at least one zeolite, then performing a drying operation, and then performing an optional calcination, so that the metal in the form of an oxide can be obtained. Before using the catalyst in a hydrocracking process of hydrocarbon fractions, the catalyst is usually sulfided to obtain the metal in a sulfided or partially sulfided form.

[0202] When an organic compound is present, the catalyst is preferably not calcined during its preparation, that is, the impregnated catalyst precursor does not undergo a heat treatment step at a temperature above 200 °C in an inert atmosphere or in an oxygen-containing atmosphere, with or without water.

[0203] Alternatively, the catalyst can undergo a calcination step during its preparation, i.e., the impregnated catalyst precursor is heat-treated in an inert or oxygen-containing atmosphere, with or without water, at a temperature of 200 °C to 1000 °C, preferably 250 °C to 750 °C, typically for a period of 15 minutes to 10 hours.

[0204] An example of a preferred catalyst comprises at least one Group VI metal and at least one Group VIII non-noble metal (except iron), amorphous silica-alumina, and an alumina binder, preferably consisting of the same.

[0205] Another example of a catalyst comprises nickel, molybdenum, amorphous silica-alumina, alumina, and optionally phosphorus, preferably consisting of the same.

[0206] Operations of steps (a1) and (a2)

[0207] Equipment items

[0208] Steps (a1) and (a2) can be carried out in the same reactor or in two separate reactors.

[0209] Preferably, steps (a1) and (a2) are carried out in the same reactor.

[0210] According to one or more embodiments, steps (a1) and (a2) are carried out in the same fluidized bed reactor.

[0211] According to one or more embodiments, steps (a1) and (a2) are carried out in two separate reactors, and steps (a1) and (a2) are carried out in two separate fluidized bed reactors.

[0212] According to one or more embodiments, steps (a1) and (a2) are carried out in two separate reactors, step (a1) is carried out in a fluidized bed reactor, and step (a2) is carried out in a fixed bed reactor.

[0213] Several reactors arranged in series or parallel can be used to carry out step (a1) and / or step (a2).

[0214] When steps (a1) and (a2) are carried out in the same reactor, the hydroconversion is carried out in a "one-pot" process, i.e., the hydroconversion reactions of steps (a1) and (a2) are carried out simultaneously in the same reaction medium. Carrying out steps (a1) and (a2) in the same reactor can particularly limit the number of equipment required for hydroconversion and simplify the operation.

[0215] One or more embodiments carried out in separate reactors according to steps (a1) and (a2) may employ reactors of different technologies. For example, for step (a1), a two-phase (gas phase and liquid phase) reactor, a fluidized bed, or a slurry-type three-phase (gas phase, liquid phase, and solid phase) reactor may be used, where the solid phase is not a catalyst but a plastic feedstock. For step (a2), a fixed-bed three-phase reactor may be used. In this way, the method exhibits particular flexibility in introducing the plastic feedstock into the first hydroconversion reactor.

[0216] Carrying out steps (a1) and (a2) in two separate reactors also allows for more flexible operating conditions. For example, they can be operated at different pressures, such as the pressure in step (a1) being higher than that in step (a2), or at different or differently controlled temperatures. For example, a fluidized bed reactor can be used in step (a1) and a fixed-bed reactor in step (a2).

[0217] When steps (a1) and (a2) are carried out in separate reactors, an intermediate gas / liquid separation can be provided between the two steps (a1) and (a2). The advantage of this separation is that a smaller second reactor for step (a2) can be used, or the residence time can be longer. This also has the advantage of being able to use less catalyst, especially in the case of a fluidized bed reactor.

[0218] The reactors employed in steps (a1) and (a2) of the method of the present invention can be hydroconversion reactors.

[0219] The term "hydroconversion reactor" refers to any vessel in which the hydroconversion of a feedstock is the main purpose, such as the cracking of a feedstock (i.e., reduction of the boiling point range) in the presence of hydrogen and a hydroconversion catalyst. A hydroconversion reactor typically includes at least one inlet through which the feedstock and hydrogen can be introduced, and at least one outlet through which the reformed material can be withdrawn. Specifically, hydroconversion reactors also have the following characteristics: they have sufficient thermal energy to break larger molecules into smaller molecules by thermal decomposition. Typically, hydroconversion reactors include, but are not limited to: entrained bed reactors, also known as slurry reactors (reactors with three phases - liquid, gas, solid - where the solid and liquid phases can appear homogeneous), fluidized bed reactors (fluidized bed reactors with three phases), moving bed reactors (reactors with three phases where the solid catalyst moves downward and the liquid and gas flow upward or downward), and fixed bed reactors (reactors with three phases where the liquid feedstock flows downward onto a fixed bed of supported catalyst, and hydrogen usually flows simultaneously with the liquid, but may flow countercurrently in some cases).

[0220] If step (a1) is carried out in a different reactor than step (a2), step (a1) may be carried out in any type of reactor corresponding to the above definition of a hydroconversion reactor, but without the need for a catalyst.

[0221] According to one or more embodiments of the present invention, the plastic feedstock is introduced into the first hydroconversion reactor by extrusion, and is therefore introduced substantially in liquid form, as described above for optional step (a0). In these cases, a hydroconversion reactor of the fixed bed, moving bed or ebullating bed reactor type as described above can be used.

[0222] According to one or more embodiments, step (a2) is carried out in at least one ebullated bed hydroconversion reactor. When steps (a1) and (a2) are carried out in the same reactor, such an ebullated bed reactor is suitable for introducing the plastic feedstock in essentially liquid form, for example at the end of extrusion, as described above, and is also more suitable for the case where the plastic feedstock is introduced in the form of solid particles, optionally suspended in a liquid, for example, as also described above for optional step (a0).

[0223] The ebullating bed hydroconversion reactor contains a hydroconversion catalyst held in the reactor. According to one or more embodiments of the present invention, one or more hydroconversion reactors can be operated in series and / or in parallel in an ebullating bed mode for H-Oil TM Methods, for example, as described in patents US4521295 or US4495060 or US4457831 or US4354852, in the paper AIChE, March 19-23, 1995, Houston, Texas, paper number 46d, "Second generation ebullated bed technology", or in 2013 by The work "Catalysis by Transition Metal Sulphides" published by Technip, Chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions". According to these embodiments, the reactor is operated in the "ebullated bed" fluidized bed mode. The reactor advantageously comprises a recirculation pump which makes it possible to maintain the porous supported solid hydroconversion catalyst as an ebullated bed by continuously recirculating at least a portion of the liquid fraction withdrawn in the upper part of the reactor and reinjected in the lower part of the reactor.

[0224] The fluidized bed reactor preferably includes at least one inlet orifice located in or near the lower part of the reactor, through which the plastic raw material and hydrogen are introduced, and at least one outlet orifice located in or near the upper part of the reactor, through which the conversion products are withdrawn. The reactor also preferably includes an inlet and an outlet for the supported catalyst, which are connected to the means for injecting and withdrawing the supported catalyst.

[0225] The fluidized bed reactor also includes an expanded catalyst zone containing a porous supported catalyst. The fluidized bed reactor also includes a lower zone without supported catalyst located below the expanded catalyst zone and an upper zone without supported catalyst located above the expanded catalyst zone. The raw material in the fluidized bed reactor is continuously circulated from the upper zone without supported catalyst to the lower zone without supported catalyst through a recirculation pipe communicating with a fluidizing pump. Preferably, a funnel-shaped recirculation tray is located in the upper part of the recirculation pipe, through which the raw material is sucked out from the upper zone without supported catalyst. The internally recirculated raw material is mixed with "fresh" raw material and additional hydrogen.

[0226] The means for injecting and withdrawing the catalyst enables continuous replacement of the supported catalyst, which is one of the advantages of fluidized bed technology compared to other types of reactors (such as fixed bed reactors), for which it may be necessary to shut down the reactor to replace the spent catalyst (deactivated mainly due to the deposition of metals contained in the raw material, such as in the form of vanadium sulfide and nickel sulfide, and the deposition of coke). The spent catalyst removed from the reactor can be sent to a regeneration zone, where the carbon and sulfur contained therein are removed. The spent catalyst removed from the reactor can also be sent to a rejuvenation zone, where most of the deposited metals are removed, and then the spent catalyst and the rejuvenated catalyst are sent to the regeneration zone, where the carbon and sulfur contained therein are removed. Subsequently, the regenerated or rejuvenated catalyst can be reintroduced into the reactor through the catalyst injection means, optionally in combination with fresh catalyst. Such removal and additional addition of the catalyst can be carried out, for example, daily. Usually, the means for injecting and withdrawing the supported catalyst includes at least one pipe located in the expanded zone of the supported catalyst in the reactor, for introducing fresh (and / or regenerated and / or rejuvenated) supported catalyst into the expanded zone of the supported catalyst in the reactor and removing the spent catalyst from said zone. The introduction and removal can be carried out with the same pipe, or through independent pipes, which requires at least two pipes, one injection pipe for injecting the supported catalyst into the reactor and one pipe for removing the spent catalyst. By such continuous replacement of the catalyst, fluidized bed technology can generally increase the time between two shutdowns of the conversion process.

[0227] As a hydroconversion reactor of the fluidized bed, since the supported catalyst is kept agitated by means of a large amount of liquid recirculation, the pressure drop in the reactor remains at a low level and is constant. The heat of reaction is rapidly averaged over the catalyst bed, so that the catalyst bed is virtually isothermal and no cooling stream (quench) needs to be injected.

[0228] Operating conditions

[0229] The hydroconversion process of the present invention is carried out in each reactor or a single reactor under the following conditions: an absolute pressure of 1 MPa to 38 MPa, a temperature of 200 °C to 550 °C, and a space velocity (where "HSV" stands for space velocity, usually referred to as "LHSV", representing "liquid hourly space velocity") of 0.05 h -1 to 10 h -1 , a hydrogen amount of 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 .

[0230] It should be understood that when implementing the embodiment including a fixed bed, the temperature of these steps is the temperature at the start of operation, also referred to as the "start of run" temperature. For other types of reactors, such as fluidized bed reactors, there is no concept of start of run temperature because the temperature remains substantially constant during operation. However, it can be considered that the operating temperature given for these steps (a1) and (a2) is the temperature at the start of operation in all cases, for example, in the case of a fluidized bed reactor, this temperature remains constant during operation.

[0231] For a fixed bed reactor, HSV is usually expressed as the ratio of the volume flow rate of the feedstock (preferably a liquid feedstock) under standard temperature and pressure conditions to the volume of the catalyst charged to the reactor.

[0232] For a fluidized bed reactor, HSV is usually expressed as the ratio of the volume flow rate of the feedstock (preferably a liquid feedstock) under standard temperature and pressure conditions to the volume of the reactor.

[0233] Therefore, the two steps (a1) and (a2) are carried out under the above conditions.

[0234] According to one or more embodiments, steps (a1) and (a2) are carried out under the following conditions:

[0235] - an absolute pressure of 2 MPa to 25 MPa, preferably 3 to 20 MPa,

[0236] - a temperature of 250 °C to 480 °C, preferably 300 °C to 480 °C, more preferably 320 °C to 450 °C, more preferably 330 °C to 435 °C, for example, at 380 °C,

[0237] - For each reactor, the space velocity is 0.1 h -1 to 10 h -1 , preferably 0.1 h -1 to 5 h -1 ,

[0238] - The amount of hydrogen is 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 , preferably 100 Sm 3 / m 3 to 2000 Sm 3 / m 3 , very preferably 200 Sm 3 / m 3 to 1000 Sm 3 / m 3 。

[0239] According to one or more other embodiments, step (a1) or steps (a1) and (a2) are carried out using at least one fluidized bed reactor, at a space velocity of 0.15 h -1 to 2 h -1 , more preferably 0.15 h -1 to 1 h -1 for operation of the space velocity.

[0240] According to one or more other embodiments, step (a1) or steps (a1) and (a2) are carried out using at least one fluidized bed reactor, and the total HSV, i.e., the flow rate of the liquid feedstock in step (a1) under standard temperature and pressure conditions relative to the total volume of the reactors in steps (a1) and (a2), is 0.05 h -1 to 0.09 h -1 。

[0241] Compared with other methods, such as pyrolysis, this method is operated at a relatively low temperature, making this method more economical in terms of energy, operation, and capital costs. Examples

[0242] The following examples are intended to show certain performance qualities of the method of the present invention compared with methods of the prior art.

[0243] Examples 1 to 5 are not in accordance with the present invention. Example 6 is in accordance with the present invention.

[0244] In the following examples, a polypropylene plastic (weight average molecular weight MW = 456000 Da and number average molecular weight Mn = 76800 Da) feedstock is introduced in the form of solid particles into an autoclave reactor (hereinafter also referred to as a batch reactor).

[0245] The operating conditions are as follows:

[0246] The reaction temperature is 380 °C,

[0247] H 2 The partial pressure: 7 MPa,

[0248] The test duration: 150 minutes,

[0249] The stirring speed: 1400 rpm.

[0250] The procedure for all the following examples: Charge the plastic raw material, the catalyst pre-activated by a vulcanization procedure known to those skilled in the art, and DMDS (if used) into a batch reactor. Close the reactor, purge with nitrogen and then with hydrogen, and then pressurize with hydrogen to a pressure of about 3 MPa. Subsequently, heat the reactor to the test temperature. Start stirring from 300 °C. When the reaction temperature is reached, instantaneously adjust the pressure in the reactor to the target value. At this time, count down the reaction time. At the end of the experimental duration, rapidly cool the reactor to stop the reaction and stop stirring. Recover the liquid and gas effluents and separate them from any possible unreacted solid products. 2 At the end of the experiment, quickly cool the reactor to stop the reaction and stop stirring. Recover the liquid and gas effluents and separate them from any possible unreacted solid products.

[0251] The results regarding the conversion products and the quality of the hydroconversion performance are summarized in Table 1 below.

[0252] Example 1: A hydroconversion method without a sulfur-based radical source and without a catalyst (not according to the present invention)

[0253] In the absence of a sulfur-based radical source or a catalyst, no conversion of the plastic raw material was observed: 100% of the plastic raw material was solid at the end of the test.

[0254] Example 2: A hydroconversion method using a sulfur-based radical source containing 4 wt% sulfur and not using a catalyst (not according to the present invention)

[0255] In this Example 2, a sulfur-based radical source, namely DMDS, was added in a proportion of 4 wt% sulfur (relative to the weight of the plastic raw material). A conversion of the plastic raw material of 93.5% (yield of non-solid products) relative to the raw material was observed, and the yield of the liquid product was 93 wt% relative to the raw material.

[0256] The yields of the products and the composition of the liquid product are shown in Table 1.

[0257] Example 3: A hydroconversion method not using a sulfur-based radical source and using catalyst C1 (not according to the present invention)

[0258] The weight ratio of catalyst C1 is 10% catalyst relative to the feedstock. Catalyst C1 is a catalyst composed of 17% by weight of WO on a support, 3 3% by weight of MoO 3 and 2.2% by weight of NiO (relative to the catalyst), and the support contains amorphous silica-alumina in an alumina matrix, which contains 27% by weight of SiO 2 .

[0259] The conversion rate of the plastic feedstock is 5% relative to the feedstock. In addition, all liquid products belong to the super heavy fraction with an initial boiling point greater than or equal to 740 °C.

[0260] The yield of the product and the composition of the liquid product are shown in Table 1.

[0261] Example 4: A hydroconversion method using a sulfur-based radical source containing 1% sulfur and catalyst C1 (not according to the present invention)

[0262] The weight ratio of catalyst C1 is 10% catalyst relative to the feedstock.

[0263] In this Example 4, the sulfur-based radical source is DMDS, and its addition ratio is 1% sulfur relative to the weight of the plastic feedstock.

[0264] It was observed that the conversion rate of the plastic feedstock was 59% relative to the feedstock, and the yield of the liquid product was low (only 56%). In addition, all products belonged to the super heavy fraction with an initial boiling point greater than or equal to 740 °C.

[0265] The yield of the product and the composition of the liquid product are shown in Table 1.

[0266] Example 5: A hydroconversion method using a sulfur-based radical source containing 4% sulfur and catalyst C2 (not according to the present invention)

[0267] The weight ratio of catalyst C2 is 10% catalyst relative to the feedstock.

[0268] Catalyst C2 is a catalyst containing 5% by weight of Fe relative to the catalyst on a support, and the support only contains amorphous silica-alumina, which contains 20% by weight of SiO relative to the amorphous silica-alumina 2 .

[0269] In this Example 5, the sulfur-based radical source is DMDS, and its addition ratio is 4% sulfur relative to the weight of the plastic feedstock.

[0270] The conversion of the plastic feedstock was observed, and the yield of non-solid products was 93 wt% relative to the feedstock, including a 75 wt% yield of liquid products and an 18 wt% yield of gaseous products.

[0271] The yields of the products and the composition of the liquid products are shown in Table 1.

[0272] Example 6: A hydroconversion process (according to the present invention) using a sulfur-based radical source and catalyst C1 containing 4 wt% sulfur

[0273] The weight ratio of catalyst C1 was 10% catalyst relative to the feedstock.

[0274] In this Example 6, the sulfur-based radical source was DMDS, and its addition ratio was 4 wt% sulfur relative to the weight of the plastic feedstock.

[0275] The conversion of the plastic feedstock was observed, and the yield of non-solid products was 99 wt% relative to the feedstock, including a 94 wt% yield of liquid products and a 5 wt% yield of gaseous products.

[0276] Compared with Example 2 using the same sulfur-based radical source in the same proportion but without using a catalyst, the following differences were noted for the following fractions: very heavy products (540 °C+)-54 percentage points, heavy products (370 °C-540 °C)-4 percentage points, gas oil fraction (250 °C-370 °C)+15 percentage points, kerosene (150 °C-250 °C)+23 percentage points, naphtha (80 °C-150 °C)+14 percentage points, indicating a higher selectivity for the kerosene, gas oil, and naphtha fractions, especially for the kerosene fraction, which can be more easily upgraded.

[0277] Compared with Example 5 using the same sulfur-based radical source in the same proportion but using a different ineffective catalyst (containing iron), it is noted that the amount of gas produced is much lower compared to the amount of liquid products produced, which maximizes the amount of potentially upgradable products. In addition, compared with Example 5, the following differences were noted for the following fractions: very heavy products (540 °C+)-10 percentage points, heavy products (370 °C-540 °C)-6 percentage points, gas oil fraction (250 °C-370 °C)+11 percentage points, kerosene (150 °C-250 °C)+21 percentage points, very light products (IP-80 °C)-14 percentage points, indicating a higher selectivity for the kerosene and gas oil fractions, especially for the kerosene fraction, which can be more easily upgraded, thereby minimizing the production of very light products and less upgradable products.

[0278] The yields of the products and the composition of the liquid products are shown in Table 1.

[0279] A summary of the main data, including the yield of the product of the embodiment and the composition of the liquid product, is given in Table 1 below.

[0280] Table 1

[0281]

Claims

1. A method for the hydroconversion of a plastic raw material, comprising the following steps: (a1) A step of non-catalytic hydroconversion of the raw material by contacting it with a radical source in the presence of hydrogen, the radical source containing sulfur and being introduced such that the sulfur content is 3 wt% to 20 wt% relative to the weight of the plastic raw material, to produce a first conversion product; (a2) A step of catalytic hydroconversion of the first conversion product by contacting it with at least one hydroconversion catalyst in the presence of hydrogen, the hydroconversion catalyst comprising at least one hydrodehydrogenation element and a porous non-zeolite support comprising at least one amorphous silica-alumina, the hydrodehydrogenation element being selected from non-noble metal elements of Groups VIB and VIII of the Periodic Table, alone or as a mixture, excluding iron; The steps (a1) and (a2) are carried out under the conditions of an absolute pressure of 1 MPa to 38 MPa, a temperature of 200 °C to 550 °C, a space velocity of 0.05 h -1 to 10 h -1 , a hydrogen gas volume of 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 .

2. The hydroconversion method according to claim 1, wherein steps (a1) and (a2) are carried out in the same reactor.

3. The hydroconversion method according to claim 2, wherein steps (a1) and (a2) are carried out in the same fluidized bed reactor.

4. The hydroconversion method according to claim 1, wherein steps (a1) and (a2) are carried out in two separate reactors, preferably steps (a1) and (a2) are carried out in two separate fluidized bed reactors, or step (a1) is carried out in a fluidized bed reactor and step (a2) is carried out in a fixed bed reactor.

5. The hydroconversion method according to any one of the preceding claims, wherein the at least one amorphous silica-alumina has a silica content of 5 wt% to 95 wt%, preferably 10 wt% to 70 wt%.

6. The hydroconversion method according to any one of the preceding claims, wherein the hydroconversion catalyst comprises: - 0.1 wt% to 99.8 wt% of amorphous silica-alumina relative to the total weight of the catalyst; - 0.1 wt% to 50 wt% of the at least one hydrodehydrogenation element composed of non-noble metal elements of Groups VIB and VIII, excluding iron, expressed as the weight of the oxide, relative to the total weight of the catalyst; - 0 wt% to 99.8 wt% of a porous mineral matrix, expressed as the weight of the oxide, relative to the total weight of the catalyst; - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one element selected from phosphorus, boron, and silicon, expressed as the weight of the oxide, relative to the total weight of the catalyst; - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one Group VIIA element; - 0 wt% to 20 wt%, preferably 0.1 wt% to 20 wt% of at least one Group VIIB element; - 0 wt% to 60 wt%, preferably 0.1 wt% to 60 wt% of at least one Group VB element; The percentages are expressed as weight percentages, and the sum of the percentages of the elements constituting the catalyst is equal to 100% relative to the total weight of the catalyst.

7. The hydroconversion process according to any one of the preceding claims, wherein the hydroconversion catalyst comprises a porous mineral matrix composed of at least one high-melting-point oxide selected from alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or as a mixture, and preferably the porous mineral matrix is alumina.

8. The hydroconversion process according to claim 7, wherein the hydroconversion catalyst comprises from 0.1% to 99.8% of the porous mineral matrix.

9. The hydroconversion process according to any one of the preceding claims, wherein the hydroconversion catalyst comprises at least one Group VIII non-noble metal selected from nickel and cobalt, preferably nickel, and at least one Group VIB metal selected from molybdenum and tungsten as hydrodehydrogenation elements.

10. The hydroconversion process according to any one of the preceding claims, wherein the sulfur content in step (a1) is from 3% to 15% by weight, preferably from 3% to 10% by weight of the plastic feedstock.

11. The hydroconversion process according to any one of the preceding claims, wherein the sulfur-containing radical source is selected from H 2 S, elemental sulfur, carbon disulfide (CS 2 ), dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), diethyl sulfide (DES), dimethyl disulfide (DMDS, molecular formula (CH 3 S) 2 ), mercaptans and polysulfides, such as di-tert-nonyl polysulfide, alone or as a mixture, and preferably selected from H 2 S, DMS, DMDS and DES.

12. The hydroconversion process according to any one of the preceding claims, further comprising: (a0) A preliminary step of conditioning the feedstock to introduce it into the reactor, in which at least the first step (a1) is carried out, and the step (a0) comprises: - feeding the plastic feedstock in the form of solid particles into an extruder, preferably together with a plastic diluent, gradually heating it in the extruder to a temperature above the melting point of the plastic feedstock, and subjecting it to the pressure of the first hydroconversion reactor during transportation, and - introducing the extruded plastic feedstock into the reactor.

13. The hydroconversion process according to any one of the preceding claims, wherein the plastic feedstock is in solid form and comprises one or more polymers selected from olefin polymers, diene polymers, vinyl polymers, and styrene polymers, polyesters, and polyamides, and preferably the plastic feedstock comprises at least 50% by weight of polyolefins, based on the total weight of the plastic feedstock, and the polyolefins are preferably selected from polyethylene, polypropylene, and / or copolymers of ethylene and propylene.

14. The hydroconversion process according to any one of the preceding claims, wherein steps (a1) and (a2) are carried out at an absolute pressure of from 2 MPa to 25 MPa and a temperature of from 300 °C to 480 °C.

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