Hydroconversion of plastic feedstocks promoted by sulfur in presence of bifunctional zeolite catalyst

Abstract

The invention relates to a process for the hydroconversion of a plastic feedstock, comprising: (a1) a non-catalytic hydroconversion step of the feedstock in the presence of hydrogen in contact with a source of free radicals, the source comprising sulfur and introduced such that the sulfur content is between 3% and 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, alone or as a mixture, at least one hydrogenation-dehydrogenation element selected from the group consisting of non-noble metal elements of Group VIB and Group VIII of the Periodic Table; and a porous support containing a porous mineral matrix and at least one zeolite, said steps (a1) and (a2) being carried out at a pressure between 1 MPa and 38 MPa absolute, at a temperature greater than or equal to 200 DEG C and less than 400 DEG C, at an hourly space velocity relative to each hydroconversion reactor between 0.05 h-1 and 10 h-1, and at a hydrogen amount between 50 and 5000 Sm3 / m3.

Description

Field of the Invention

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

[0002] In the context of the circular economy and waste reduction, particular attention is paid to plastics in order to upgrade them, plastics being conventionally petroleum-derived products.

[0003] The upgrading of plastic waste can include converting the plastics by mechanical and / or chemical means so as to be able to produce plastics or plastic-based objects again. This is the recycling of plastic waste.

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

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

[0006] The French patent application registered by the applicant company under application number 21 / 14,037 thus relates to the incorporation of a plastic fraction, usually derived from waste, into a fossil heavy hydrocarbon feedstock in a fluidized bed or hybrid fluidized-bed / entrained-bed hydroconversion process to produce fuel bases and other upgradable hydrocarbons. The initially solid plastic fraction is introduced into the hydroconversion reactor in different ways, and the overall conversion level exhibited by the process is close to the overall conversion level obtained with this same type of process treating a more conventional 100% fossil-source heavy feedstock.

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

[0008] A successive review by Munir et al., 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 in the absence of co - feed. The authors concluded that an increase in reaction temperature led to an increase in conversion and an increase in the production of undesirable gases and coke. The authors recommended a temperature not higher than 400 °C in the presence of a catalyst. The authors also pointed out that bifunctional catalysts with both hydrogenation - dehydrogenation and cracking capabilities were most suitable for the cracking of plastics.

[0009] The review particularly mentioned the 1998 publication by Joo and Curtis (Catalytic coprocessing of LDPE with coal and petroleum resid using different catalysts. Fuel Process Technol. 1998, 53, pp. 197 - 214), where a bifunctional NiMo / zeolite (pre - sulfided) catalyst was particularly tested for the hydrocracking of LDPE (low - density polyethylene). At 400 °C, the resulting conversion was less than 30%. At 430 °C, the conversion became more significant. At such a high reaction temperature, the tested bifunctional zeolite catalyst showed improved activity compared to other alumina - based catalysts. However, the amount of gas and products lighter than naphtha produced was high.

[0010] The review also mentioned the 2001 publication by Walendziewski and Steininger (Thermal and catalytic conversion of waste polyolefines. Catal. Today 2001, 65, pp. 323 - 330), which gave the results of the hydrocracking of waste polyethylene (PE) using a commercial bifunctional NiW + 10% HY catalyst. The authors concluded that the optimal temperature for plastic liquefaction was between 410 °C and 430 °C or at least 390 °C. At 410 °C, in the presence of such a catalyst, a very large amount of gas was produced.

[0011] In the studies listed in the review by Munir et al., 2008, some studies have demonstrated the potential of using sulfur to promote plastic conversion.

[0012] 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 between 380 °C and 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, in the presence or absence of the catalyst. The authors concluded that sulfur in the reactor was a promoter of PP conversion and proposed an explanatory mechanism whereby hydrocarbon radicals were formed 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, they could diffuse into the structure of the polymer, and the hydrogen atoms of H 2 S had the potential to be captured by hydrocarbon radicals to form stable hydrocarbons and HS· radicals. The lifetime of the hydrocarbon radicals was thus reduced and their recombination was prevented, and their potential to continue thermal cracking (which usually led to an unfavorable gas yield) was also reduced. Thus, thermal cracking had the potential to convert large polymer molecules into long molecules, which did not overcrack due to the stabilization of the radicals by H 2 S. These long molecules could then undergo selective catalytic cracking. This was because the yields of the various fractions varied depending on the catalyst used, especially the yield of the gas product, which remained high, especially in the case of the tested catalysts based on iron supported on amorphous silica-alumina, and even higher when combined with CS 2 .

[0013] Ibrahim and Seehra (Ibrahim and Seehra, Energy & Fuels, 11, 1997, 926 - 930) studied the depolymerization temperature (Td) of a plastic mixture monitored by electron spin resonance (ESR) at an initial hydrogen pressure of 500 psig (3.45 MPa). A plastic sample consisting of 5% PP, 95% high-density polyethylene (HDPE), and trace (<3%) polyethylene terephthalate (PET) was mixed with other compounds: elemental sulfur or elemental sulfur (S) and NiMo / Al 2 O 3A mixture of catalysts, 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. An increase in 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 during its thermal cracking process via a free radical mechanism. Their study did not give information on the conversion of plastic into fuel.

[0014] 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 between 300 °C and 425 °C. Sulfur compounds such as H 2 S, elemental sulfur, dimethyl disulfide (DMDS of formula (CH 3 S) 2 etc.) were added. The authors concluded that the addition of sulfur compounds had a promoting effect on the decomposition of LDPE.

[0015] The addition of sulfur or sulfur compounds is known in hydroconversion processes to sulfide the catalyst and thereby make it "active". Conventionally, it is advantageous to subject the catalyst to a sulfiding treatment so that it is possible to convert at least part of the metal entities into a sulfided form before the metal entities come into contact with the feedstock to be treated. This activation treatment by sulfidation is well known to those skilled in the art.

[0016] 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 the 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., under activation-appropriate conditions before loading the catalyst in a step of the hydroconversion process.

[0017] For example, in the field of conversion of feedstocks containing plastics, the French patent application with application number 21 / 14.037 mentioned above describes the possibility of in situ forming and activating a colloidal or molecular catalyst (which is a very small (e.g., with a size less than 1 μm) dispersed catalyst (also called an entrained catalyst or slurry)) by the interaction of sulfur with a soluble catalyst precursor usually at high temperature and 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) from the fossil hydrocarbon fractions introduced into the feedstock to be treated.

[0018] relates to the liquefaction of plastic waste mixed with a suspending agent in a container under H 2 or N 2 Patent application CA2171803 describes the possibility of adding a sulfurizing agent to sulfide metals that may be present as catalysts, in particular iron, under pressure, either alone or as a mixture, and optionally in the presence of a solid catalyst.

[0019] Due to the problems of managing plastic waste and environmental issues being more concerned than ever, efficient methods for converting plastic waste into fuels or raw materials for the petrochemical industry have been sought, which are particularly energy-efficient and cost-effective, and can meet different or changing demands for products (such as fuels).

[0020] Object and Summary of the Invention

[0021] In the above context, an object of the present invention is to provide a method for converting plastics into a mixture of reformable hydrocarbons in the presence of hydrogen, which can achieve maximum conversion of plastics while minimizing the energy required for conversion and the gas production during the conversion process to improve the relative yield of the liquid products of interest.

[0022] Accordingly, in a first aspect, the present invention provides a method for hydroconverting a plastic feedstock, which comprises the following steps:

[0023] (a1) A non-catalytic hydroconversion step of the feedstock in the presence of hydrogen in contact with a radical source, the source containing sulfur and introduced such that the sulfur content is between 3 wt% and 20 wt% based on the weight of the plastic feedstock, to produce a first conversion product;

[0024] (a2) A catalytic hydroconversion step of the first conversion product in the presence of hydrogen in contact with at least one hydroconversion catalyst, the hydroconversion catalyst comprising at least one hydrogenation-dehydrogenation element selected from non-noble metal elements of Groups VIB and VIII of the periodic table, either alone or as a mixture, and a porous support containing a porous mineral matrix and at least one zeolite,

[0025] The steps (a1) and (a2) are carried out at an absolute pressure between 1 MPa and 38 MPa, at a temperature greater than or equal to 200 °C and less than 400 °C, at a space velocity with respect to each hydroconversion reactor between 0.05 h -1 to 10 h -1 and at a hydrogen amount between 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 between.

[0026] Compared with other plastic conversion technologies, especially pyrolysis, the advantages of the method according to the invention are in particular that it is more economical in terms of energy and in terms of operating and investment costs due to its operation at a lower temperature than pyrolysis.

[0027] The method according to the invention also enables the composition of the resulting product to be modified, in particular by the selectivity provided by the catalyst during the second catalytic hydroconversion step, which can be selected according to the intended end use (for example kerosene for the aviation sector, diesel or gasoline for the automotive sector, naphtha for steam cracking, etc.).

[0028] According to one or more embodiments of the invention, steps (a1) and (a2) are carried out in the same reactor, preferably in the same fluidized bed reactor.

[0029] According to one or more embodiments of the invention, 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.

[0030] According to one or more embodiments of the invention, said at least one zeolite of the hydroconversion catalyst support is selected from FAU-type zeolites, preferably FAU-type zeolites selected from zeolite X, Y, USY, dealuminated Y, BEA, ISV, IWR, IWW, MEI, UWY, MEL, MTW, MTT, MSE, FER and MFI, and said at least one zeolite is preferably selected from FAU or BEA-type zeolites.

[0031] According to one or more embodiments of the invention, the catalyst support comprises USY zeolite and / or β zeolite.

[0032] According to one or more embodiments of the invention, the hydroconversion catalyst support comprises at least one zeolite selected from ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 and ZBM-30.

[0033] According to one or more embodiments of the invention, the hydroconversion catalyst comprises:

[0034] - at least one hydro-dehydrogenation element selected from Group VIB and Group VIII non-precious metal elements, expressed in weight of oxide, between 0.1% by weight and 50% by weight relative to the total weight of the catalyst;

[0035] - A porous support in the range of 0.1 wt% to 99.9 wt% based on the total weight of the catalyst, the support comprising zeolite in the range of 0.1 wt% to 80 wt% based on the total weight of the support and a porous mineral matrix in the range of 0.1 wt% to 99.9 wt% expressed as the weight of the oxide based on the total weight of the support;

[0036] - At least one element selected from phosphorus, boron, and silicon in the range of 0 wt% to 20 wt%, preferably in the range of 0.1 wt% to 20 wt%, expressed as the weight of the oxide based on the total weight of the catalyst;

[0037] - At least one Group VIIA element in the range of 0 wt% to 20 wt%, preferably in the range of 0.1% to 20%;

[0038] - At least one Group VIIB element in the range of 0 wt% to 20 wt%, preferably in the range of 0.1% to 20%,

[0039] - At least one Group VB element in the range of 0 wt% to 60 wt%, preferably in the range of 0.1% to 60%;

[0040] The percentages are expressed as weight percentages relative to the total mass of the catalyst, and the sum of the percentages of the elements constituting the catalyst is equal to 100%;

[0041] According to one or more embodiments of the present invention, the hydroconversion catalyst comprises a porous mineral matrix composed of at least one refractory oxide selected from alumina, silica - alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or as a mixture, and the porous mineral matrix is preferably alumina.

[0042] According to one or more embodiments of the present invention, 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, preferably molybdenum, as hydrogenation - dehydrogenation elements.

[0043] According to one or more embodiments of the present invention, the source of free radicals containing sulfur is selected from H 2 S, elemental sulfur, carbon disulfide (CS 2 ), dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), diethyl sulfide (DES), dimethyl disulfide (DMDS of the formula (CH 3 S) 2 ), thiols, and polysulfides such as di - tert - nonyl polysulfide, either alone or as a mixture, and is preferably selected from H 2 S, DMS, DMDS, and DES.

[0044] According to one or more embodiments of the present invention, based on the weight of the plastic raw material, the sulfur content in step (a1) is between 3% by weight and 15% by weight, preferably between 3% by weight and 10% by weight of the raw material.

[0045] According to one or more embodiments of the present invention, the method further comprises:

[0046] (a0) A preparatory step of conditioning the raw material for introduction into a reactor for performing at least the first step (a1), the step (a0) comprising:

[0047] - feeding the plastic raw material in the form of solid particles, preferably together with a plastic diluent, into an extruder, gradually heating it therein to a temperature above the melting point of the plastic raw material, and being under the pressure of the first hydroconversion reactor during conveyance, and

[0048] - introducing the extruded plastic raw material into the reactor.

[0049] According to one or more embodiments of the present invention, the plastic raw material is in solid form and comprises one or more polymers selected from olefin polymers, diene polymers, vinyl polymers, styrene polymers, polyesters, and polyamides. The plastic raw material preferably comprises at least 50% by weight of polyolefin based on the total weight of the plastic raw material, and the polyolefin is preferably selected from polyethylene, polypropylene, and / or ethylene / propylene copolymer.

[0050] According to one or more embodiments of the present invention, steps (a1) and (a2) are carried out at an absolute pressure between 2 MPa and 25 MPa and at a temperature greater than or equal to 300 °C and less than 400 °C.

[0051] Other subjects and advantages of the present invention will become apparent upon reading the following description of specific exemplary embodiments of the present invention given as non-limiting examples. Detailed Description of the Invention

[0053] In the following detailed description, many specific details are disclosed to provide a deeper understanding of the method. However, it will be apparent to those skilled in the art that the method may not necessarily be implemented with all these specific details. In other cases, well-known features are not described in detail to avoid unnecessarily complicating the description.

[0054] Some definitions are given below for better understanding of the present invention.

[0055] In this specification, the term "comprising" is synonymous with "including" and "containing" (having the same meaning), and is inclusive or open-ended and does not exclude other elements not mentioned. It is to be understood that the term "comprising" includes the exclusive and closed term "consisting of".

[0056] In this specification, unless otherwise indicated, the expression "between... and..." means that the limiting values of the interval are included within the described numerical range.

[0057] In the present invention, different numerical ranges of a given parameter can be used alone or in combination. For example, a preferred range of a pressure value can be combined with a more preferred range of a temperature value, or a preferred range of a value of one chemical compound or element can be combined with a more preferred range of a value of another chemical compound or element.

[0058] Within the meaning of the present invention, the different embodiments given can be used alone or in combination with each other without any limitation on the combination.

[0059] 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.

[0060] The term "hydroconversion" refers to a process whose main purpose is to reduce the boiling point range of a hydrocarbon feedstock and in which a large part of the feedstock is converted into products having a boiling point range lower than that of the starting feedstock. Hydroconversion generally involves breaking larger molecules (usually hydrocarbons) into smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen / carbon (H / C) ratio. The reactions carried out during hydroconversion enable the size of hydrocarbon molecules to be reduced mainly by the breaking of carbon - carbon bonds in the presence of hydrogen to saturate the severed bonds and aromatic rings. The mechanism by which hydroconversion occurs generally involves the formation of free radicals, usually hydrocarbon free radicals, during a breaking process that is mainly by thermal cracking, followed by capping the ends or fragments of the free radicals with hydrogen in the presence of active catalyst sites. Of course, during the process of the hydroconversion process, other reactions that are usually associated with hydrotreating can occur, in particular, for example, the removal of sulfur and nitrogen from the feedstock, or the saturation of olefins, and are more broadly defined below. In French terminology, the term "hydroconversion" is more reserved for processes that treat heavy petroleum feedstocks, such as atmospheric residue and vacuum residue (but not only), while the term "hydrocracking" is more reserved for processes that treat lighter feedstocks, such as vacuum distillates and gas oils. In English terminology, the terms "hydroconversion" and "hydrocracking" are generally used without distinction. In this specification, the terms "hydrocracking" and "hydroconversion" are synonymous, and the feedstock being treated is of the plastic type.

[0061] The term "hydrotreating", commonly known as "HDT", refers to a milder operation whose main purpose is to remove impurities such as sulfur, nitrogen, oxygen, halides, and trace metals from the feedstock, and to saturate olefins and / or stabilize free radicals, usually hydrocarbon free radicals, 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 known as "HDS") reactions, hydrodenitrogenation (commonly known as "HDN") reactions, and hydrodemetallization (commonly known as "HDM") reactions, along with hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, or hydrodewaxing reactions and along with a reduction in Conradson carbon residue. Hydrotreating is most commonly carried out using fixed-bed reactors, although other reactors can also be used for hydrotreating, such as ebullated-bed hydrotreating reactors.

[0062] The terms "porous supported catalyst", "solid supported catalyst", and "supported catalyst" refer to catalysts commonly used in conventional ebullated-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 many interconnected channels or pores and (ii) fine particles of an active catalyst, such as sulfides of cobalt, nickel, tungsten, and molybdenum or mixed sulfides of these elements (e.g., NiMo, CoMo, etc.), dispersed within the pores. Supported catalysts are typically produced in the form of cylindrical extrudates (pellets) or spherical solids, although other forms are possible.

[0063] In this specification, according to IUPAC convention, the term "micropore" is understood to refer to pores with a diameter less than 2 nm; the term "mesopore" is understood to refer to pores with a diameter between 2 nm and 50 nm, and the term "macropore" is understood to refer to pores with a diameter greater than 50 nm.

[0064] The term "specific surface area" of a zeolite, support, or catalyst refers to the BET specific surface area determined by nitrogen adsorption according to the standard ASTM D 3663-78 established by the Brunauer-Emmett-Teller method described in the journal The Journal of the American Chemical Society, 60, 309 (1938).

[0065] The quantitative analysis of the microporosity (pores with a diameter of less than 2 nm) is carried out by means of the "t" method (Lippens-De Boer method, 1965), which corresponds to a variant 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. Eight pressure points are used, P / P0 = 0.075, 0.100, 0.125, 0.150, 0.175, 0.200, 0.250 and 0.300.

[0066] Similarly, the term "total pore volume" of a zeolite, support or catalyst refers to the volume measured by nitrogen adsorption at P / P 0 = 0.99 (at this pressure it is generally considered that nitrogen has filled all the pores).

[0067] The term "mesopore volume" of a zeolite refers to the difference between the above-mentioned total pore volume and the micropore volume.

[0068] The method according to the invention and its operation are described in more detail below.

[0069] The object of the present invention is to provide a method for hydroconverting plastic raw materials, which comprises the following steps:

[0070] (a1) A non-catalytic hydroconversion step of the raw material in the presence of hydrogen in contact with a radical source, said source containing sulfur and introduced so that the sulfur content is between 3% by weight and 20% by weight relative to the weight of the plastic raw material, to produce a first conversion product;

[0071] (a2) A catalytic hydroconversion step of the first conversion product in the presence of hydrogen in contact with at least one hydroconversion catalyst, said hydroconversion catalyst comprising at least one hydrogenation-dehydrogenation element selected from non-precious metal elements of Groups VIB and VIII of the Periodic Table, either alone or as a mixture, and a porous support containing a porous mineral matrix and at least one zeolite,

[0072] The steps (a1) and (a2) are carried out at an absolute pressure between 1 MPa and 38 MPa, at a temperature greater than or equal to 200 °C and less than 400 °C, at a space velocity relative to each hydroconversion reactor between 0.05 h -1 and 10 h -1 and at a hydrogen flow rate between 50 Sm 3 / m 3 and 5000 Sm 3 / m3 with a hydrogen amount therebetween.

[0073] feedstock

[0074] The feedstock treated in the hydroconversion process according to the present invention is a plastic feedstock.

[0075] The plastic feedstock of the process according to the present invention contains plastics, which in turn more particularly contain polymers.

[0076] Plastics or plastic materials are generally polymers, which are usually mixed with additives in order to form various materials and objects (injection-molded parts, tubes, films, fibers, fabrics, mastics, coatings, etc.) after shaping. The additives used for plastics can be organic compounds or inorganic compounds. They are, for example, fillers, colorants, pigments, plasticizers, property modifiers, flame retardants, etc.

[0077] Thus, the term "plastic feedstock" is understood to mean the solid feedstock of plastics containing one or more polymers, and which may contain other compounds, such as additives and / or conventional impurities of organic or inorganic origin, especially from the life cycle of plastic materials and products and / or from waste collection and sorting circuits. For example, conventional impurities can be metallic, organic or mineral; they can be packaging residues, food residues or compostable residues (biomass). Conventional impurities can also contain glass, wood, cardboard, paper, aluminum, iron, metal, tires, rubber, silicone, rigid polymers, thermosetting polymers, household products, chemical products or cosmetic products, waste oil, water.

[0078] In the present specification, the term "impurities of plastics" denotes all compounds that are initially contained in the plastic feedstock and are not polymers and cannot be converted during the steps of the process. For example, some organic additives can be at least partially converted in the process according to the present invention in the same way as polymers. These are therefore not considered impurities of plastics. On the other hand, some inorganic additives can be removed during the process, such as those containing metals and / or sulfur and / or nitrogen and / or oxygen and / or other heteroatoms (Cl, Br, etc.). They are themselves considered impurities of plastics.

[0079] The plastics contained in the plastic feedstock of the feedstock of the process according to the present invention are usually production scraps and / or wastes, especially household wastes, construction wastes or wastes of electrical and electronic equipment. Preferably, the plastic wastes are from collection and sorting channels.

[0080] The plastic feedstock according to the process of the present invention thus contains polymers, especially thermoplastics. The polymers contained in the plastic feedstock of the feedstock can be olefin polymers, diene polymers, vinyl polymers, styrene polymers (e.g.: polystyrene "PS"), polyesters and / or polyamides.

[0081] Preferably, the polymer contained 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 contained in the plastic raw material is a polyolefin (olefin polymer), such as polyethylene (PE), polypropylene (PP), and / or ethylene / propylene copolymer.

[0082] For example, the plastic raw material of the raw material contains at least 50% by weight, preferably at least 80% by weight, preferably at least 90% by weight, and very preferably at least 94% by weight of polyolefin based on the total weight of the plastic raw material.

[0083] The plastic raw material may contain a mixture of polymers, especially a mixture of thermoplastics and / or a mixture of thermoplastics and other polymers, as well as compounds other than these thermoplastics and polymers, especially additives that are advantageously used in formulating plastic materials and conventional impurities that usually originate from the life cycle of plastic materials and objects and / or from waste collection and sorting channels. The plastic raw material of the method according to the present invention usually contains less than 50% by weight of these additives and conventional impurities, preferably less than 20% by weight, and preferably less than 10% by weight.

[0084] The plastic raw material can be advantageously pretreated upstream of the method to remove at least all or part of the "coarse" conventional impurities, i.e., conventional impurities in the form of particles with a size greater than or equal to 10 mm, preferably greater than or equal to 5 mm, and even greater than or equal to 1 mm, such as conventional impurities of types like wood, paper, biomass, iron, aluminum, glass, etc., and shape it, usually in the form of particles (dispersed solids), for easy handling in the method. This pretreatment may include a grinding step, a washing step under atmospheric pressure, and / or a drying step. This pretreatment can 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 enables the content of conventional impurities to be reduced to less than 6% by weight. At the end of the pretreatment, the plastic raw material is usually stored in the form of particles, such as in the form of ground material or powder, for easy operation and transportation until the method.

[0085] (a0) Optional step of adjusting the raw material for injecting it into the first hydroconversion reactor

[0086] The method according to the present invention may include step (a0) of adjusting the plastic raw material for injecting it into the first hydroconversion reactor.

[0087] In the present specification, the term "first hydroconversion reactor" refers to the reactor in which at least step (a1) is carried out, that is, in which step (a1) is carried out or, if both steps (a1) and (a2) are carried out in the same reactor, in which both steps (a1) and (a2) are carried out. Thus, if these two steps are carried out in separate reactors, the hydroconversion reactor for step (a2) is not the first hydroconversion reactor.

[0088] The term "conditioning of the feedstock" is understood to mean the conditioning carried out for the subsequent hydroconversion step (a1) of the feedstock once it has been introduced into the first hydroconversion reactor, that is to say, bringing the feedstock into a state and temperature and pressure conditions suitable for hydroconversion in the first hydroconversion reactor.

[0089] The plastic feedstock, which is initially in solid form, can be conditioned before being fed into the first hydroconversion reactor, in particular to adapt to the type of hydroconversion reactor used and to facilitate its conversion.

[0090] According to one or more embodiments, the plastic feedstock in the form of solid particles, preferably together with a plastic diluent, is fed into an extruder, in which it is gradually heated to a temperature above the melting point of the plastic feedstock and is under the pressure of the first hydroconversion reactor during the transfer for a time preferably less than 15 minutes, and the extruded plastic feedstock is introduced into the reactor.

[0091] According to these embodiments, the plastic feedstock introduced into the first hydroconversion reactor by extrusion is in substantially liquid form.

[0092] Extrusion is conventionally a method that enables a polymer initially provided in solid form to be injected or shaped. According to one extrusion method, the material is conveyed, kneaded and heated by one or more screws, which makes it possible to melt it. At the same time, the screw conveys the material and increases its pressure, which makes it possible to inject it into a die or mold.

[0093] According to these embodiments of the present invention, the extrusion of the plastic feedstock is a means of introducing a plastic feedstock that is solid at ambient temperature into a first hydroconversion reactor operating at high pressure and high temperature. Extrusion thus makes it possible to heat to liquefy the plastic feedstock and to pressurize the plastic feedstock to the operating conditions of the following reactor.

[0094] The material is not injected into a die or mold as in a conventional extrusion process and thus does not constitute a shaping process, but is directly injected into the reactor.

[0095] "Plastic diluent" is formed, for example, from light liquid hydrocarbons or mixtures of light liquid hydrocarbons. For example, the plastic diluent is a hydrocarbon oil composed of hydrocarbons, wherein at least 50% by weight, and preferably at least 80% by weight, based on the weight of the plastic diluent, has a boiling point of less than 300 °C. Examples of suitable hydrocarbon diluents include, but are not limited to, light liquid hydrocarbons (usually C5+ hydrocarbons, i.e., hydrocarbons that can contain 5 and more carbon atoms per molecule), such as xylene, toluene, gasoline, mixtures thereof, etc. The plastic diluent can act as a solvent for the plastic raw material, especially for the polymers of the plastic raw material.

[0096] During the extrusion process, it is preferred to gradually heat the plastic raw material to a temperature above its melting point in order to melt it. Advantageously, at the end of the extrusion, at least 80% by weight of the plastic raw material is in liquid form (melted), very advantageously at least 90% by weight, preferably at least 95% by weight, even 98% by weight. As mentioned above, the plastic raw material usually contains compounds other than polymers, especially impurities of the plastic. Some of these non-polymeric compounds, including the impurities of the plastic, may be insoluble and / or have a melting point higher than that of the polymers of the plastic raw material. Even if all the polymers are melted, a part of this raw material may still be in solid form considering the non-polymeric compounds. This is the case for all the steps described below, where heating leads to the complete or almost complete liquefaction of the plastic raw material.

[0097] The extrusion temperature depends on the polymer composition of the plastic raw material (the nature and proportion of the polymers).

[0098] Preferably, the extruder operates at a temperature between 25 °C lower than the melting point of the plastic raw material and 25 °C higher than the melting point of the plastic raw material.

[0099] In the case where the plastic raw material contains a mixture of polymers, the extruder operates at a temperature between 25 °C lower than the melting point of the most fusible polymer of the plastic raw material (i.e., the one with the lowest melting point) and 25 °C higher than the melting point of the least fusible polymer of the plastic raw material (i.e., the one with the highest melting point).

[0100] 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.

[0101] As an indication, the melting point of polypropylene (PP) is approximately 170 °C, the melting point of polyethylene (PE) is between approximately 85 °C and 140 °C, and the melting point of polystyrene (PS) is between approximately 240 °C and 270 °C.

[0102] Preferably, the extruder operates at a temperature between 60 °C and 295 °C, more preferably between 60 °C and 195 °C.

[0103] Advantageously, the extruder operates at a temperature between 60 °C and 165 °C to melt a plastic feedstock mainly comprising PE as a polymer.

[0104] Advantageously, the extruder operates at a temperature between 145 °C and 195 °C to melt a plastic feedstock mainly comprising PP as a polymer.

[0105] Advantageously, the extruder operates at a temperature between 215 °C and 295 °C to melt a plastic feedstock mainly comprising PS as a polymer.

[0106] The operating temperature of the extruder is advantageously adjusted according to the composition of the plastic feedstock.

[0107] Advantageously, the extruder comprises at least one screw conveying section, called the extrusion section, to which the plastic feedstock is supplied.

[0108] The residence time in this 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 preferably less than 2 minutes.

[0109] 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.

[0110] The extrusion section may also advantageously comprise a filtration system to remove solid particles of unacceptable size, such as solid particles larger than 200 μm, and preferably larger than 40 μm, such as sand grains. If a diluent is used to enable viscosity reduction, it is possible to filter particles of smaller size, such as particles larger than 3 μm.

[0111] 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 at a temperature between 60 °C and 295 °C, before introducing it into the first hydroconversion reactor. This heating step may be carried out before or after mixing with the plastic diluent, preferably after mixing with the plastic diluent.

[0112] These embodiments thus correspond to injecting the plastic feedstock in a substantially liquid form directly after mixing the plastic feedstock with the plastic diluent to form a slurry and subsequently heating it to obtain a substantially liquid plastic feedstock.

[0113] The term "plastic raw material in substantially liquid form" is 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 the polymer of the plastic raw material is in liquid form. The term "polymer of plastic raw material in liquid form" is 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.

[0114] The term "slurry" is understood to mean a mixture of substances in suspension form, which generally corresponds to a system (liquid dispersion) formed by solid particles dispersed in a liquid. 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 solid plastic particles dispersed in a liquid between 1% and 50% by weight, even between 1% and 30% by weight or between 5% and 20% by weight. The continuous liquid phase in which the solid plastic particles are dispersed can be a diluent.

[0115] These embodiments particularly have the advantage of using simple and inexpensive equipment items.

[0116] The plastic raw material in solid particle form can be premixed with a plastic diluent in a mixing section to form a suspension, and 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 to melt the solid particles of the suspended plastic raw material, and the heated plastic raw material can then 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.

[0117] Preferably, during the mixing step in the mixing section, the temperature is such that the suspension has a kinematic viscosity of less than 0.3 x 10 -3 m 2 / s, which corresponds to the viscosity of a pumpable fluid. In the case where the mixing step is separate and before the heating step, the temperature of this step is preferably lower than the temperature operating in the subsequent heating step.

[0118] The mixing section can include a mixing tank that contains dynamic stirring devices for achieving suspension, such as agitators and / or recirculation pumps.

[0119] At the end of the heating of the suspension, the plastic raw material is substantially in liquid form.

[0120] The description made of the temperature conditions of the extruder of the above other embodiments applies to the heating of the suspension and will not be repeated here.

[0121] The heating temperature can also depend on the plastic diluent used, which, according to its properties, is particularly likely to enable the suspended plastic raw material to melt at a lower temperature.

[0122] The heating section comprises any heating device known to those skilled in the art capable of heating the suspended plastic raw material and, for example, comprises an oven which comprises at least one heating compartment, and / or a tube through which the suspension flows, any suitable heat exchanger of any type, etc.

[0123] The mixing section and the heating section can form part of the same device configured to successively carry out mixing and then heating.

[0124] Before introducing it into the first hydroconversion reactor, the heated plastic raw material can be subjected, for example, to a pressurization step by means of a suitable pump to a pressure suitable for operation in the first hydroconversion reactor. It can also be subjected to a filtration step which, for example, aims to remove solid particles from the plastic raw material, which can form part of the impurities of the plastic, such as sand, glass, metal, certain additives known as fillers, etc.

[0125] According to another alternative form, the direct injection of the plastic raw material in a substantially liquid form can be carried out after having heated the said 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.

[0126] According to yet another alternative form, the mixing step and the heating step are carried out simultaneously, and the mixing section and the heating section then form part of the same device configured to carry out mixing and heating simultaneously.

[0127] According to one or more other embodiments, the direct injection of the suspended plastic raw material into the first hydroconversion reactor is carried out: preferably at a temperature greater than or equal to the ambient temperature and lower than the melting point of the said plastic raw material, the plastic raw material in the form of solid particles is first fed into a mixer to be mixed with a plastic diluent and form a suspension, and the said plastic raw material in the form of a suspension is introduced into the first hydroconversion reactor.

[0128] These embodiments also have the advantage of using simple and inexpensive items of equipment.

[0129] According to these embodiments, the plastic raw material in the form of solid particles is first fed into a mixer to be mixed with a plastic diluent and form a suspension, and then the said plastic raw material in the form of a suspension is introduced into the first hydroconversion reactor.

[0130] 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, such as 15 °C and below the melting point of the plastic raw material (or if the plastic raw material comprises a mixture of polymers, below the melting point of the polymer having the lowest melting point). A temperature slightly below the melting point of the plastic raw material may constitute the upper limit of the temperature of the mixture, since the plastic diluent used has an influence on the temperature at which the plastic raw material can be dissolved (in the case where the plastic diluent acts as a solvent) according to its properties.

[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 170 °C (e.g., very suitable for using VGO as the plastic diluent and a plastic raw material mainly comprising 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 a plastic raw material mainly comprising PP 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 140 °C, or it can also be carried out 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 a plastic raw material mainly comprising PE as the polymer.

[0133] 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 it can also be carried out 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 a plastic raw material mainly comprising 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 a plastic raw material mainly comprising PS as the polymer.

[0134] The mixing can be active or not. Examples of active mixing devices that can be used include, but are not limited to, high-shear mixing, such as in pumps with rotor agitators or propellers, multiple static in-line mixers, multiple static in-line mixers combined with high-shear in-line mixers, multiple static in-line mixers combined with high-shear in-line mixers and subsequent recirculation pumping in a storage tank, combinations of the above devices, and mixtures made in one or more multistage centrifugal pumps.

[0135] Before introducing it into the first hydroconversion reactor, a pressurization step can be applied to the suspended plastic raw material to suit the pressure at which it operates in the first hydroconversion reactor.

[0136] (a1) A thermoconversion step promoted by sulfur

[0137] According to the present invention, the method comprises a first step (a1) of non-catalytic hydroconversion of a plastic raw material in the presence of hydrogen in contact with a radical source to produce a first conversion product.

[0138] The term "non-catalytic" is understood to mean that the hydroconversion step (a1) is carried out without involving a catalytic reaction with the aid of a catalyst, i.e., a hydroconversion catalyst such as those known to be used in the course of conventional hydroconversions, which are generally porous supported catalysts or entrained catalysts formed from soluble catalyst precursors of the metal or organometallic type, also known as slurries (catalysts of very small size, e.g., with a diameter of less than 1 μm, dispersed in the reaction medium, uniformly distributed in the reactor, and entrained by the products out of the reactor).

[0139] No catalyst of this type (porous supported or slurry) participates in the reaction in step (a1) of the method according to the present invention.

[0140] The radical source contains sulfur and may be denoted in the remainder of the specification by the expression "sulfur-based radical source".

[0141] The sulfur-based radical source is introduced such that the sulfur content (elemental sulfur S) is between 3% by weight and 20% by weight, preferably between 3% by weight and 15% by weight, and more preferably between 3% by weight and 10% by weight, relative to the weight of the raw material.

[0142] According to one or more embodiments of the present 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 of the formula (CH 3 S) 2 ), thiols or polysulfides (e.g., 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, and preferably is DMDS or H 2 S.

[0143] The operating conditions are described in more detail below, and at the same time the operating conditions of the hydroconversion step (a2) are described.

[0144] Without being bound by any theory, as demonstrated in the prior art and as described above in relation to the 2 free radical mechanism involving H

[0145] S and HS· free radicals may at least partially explain the promotion of the conversion of the plastic feedstock in this step (a1) of the process according to the invention.

[0146] During this hydroconversion step, the maximum amount of the plastic feedstock is converted. In particular, the process according to the invention advantageously makes it possible to 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 feedstock into non-solid (i.e., liquid and gas) conversion products.

[0147] The first conversion product is hydrocarbons, which can be characterized by a boiling range. Conventionally, a hydrocarbon fraction is defined by an initial boiling point greater than or equal to a first temperature and a final boiling point below a second temperature, the second temperature being higher than the first temperature. For simplicity, the expression "boiling range from... to..." can be used to denote these initial boiling points (within this range) and final boiling points (outside this range).

[0148] The first conversion product also contains a small amount of gaseous products, typically gases such as C 1 to C 6 hydrocarbons (i.e., having 1 to 6 carbon atoms).

[0149] (a2) Catalytic hydroconversion step

[0150] According to the invention, the process comprises a second step (a2) of catalytic hydroconversion of the first conversion product in the presence of hydrogen in contact with at least one hydroconversion catalyst.

[0151] This second catalytic hydroconversion step (a2) forms a second conversion product.

[0152] These second conversion products are mixtures of upgradable hydrocarbons, in particular hydrocarbon fractions that can be characterized by boiling range, in particular as described for the first hydroconversion product. These fractions can be used as fuel bases or as raw materials for petrochemical products (light hydrocarbons, distillates for steam crackers, in particular for the production of recycled polyolefins, bases for the production of bitumen, lubricants, etc.), in particular directly after fractionation or also after fractionation and then one or more treatments after step (a2), such as hydrotreatment aimed at removing residual sulfur or other possible contaminants, such as nitrogen, chlorine, silicon or metals.

[0153] The second conversion products comprise 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), gasoil-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).

[0154] The second conversion products may also contain small amounts of gaseous products, generally gases such as C 1 to C 6 hydrocarbons. Preferably, less than 30% by weight of gas is produced during the course of step (a1), more preferably less than 20% by weight, and even more preferably less than 15% by weight, relative to the feedstock.

[0155] The combination of the sulfur-promoted first hydroconversion step (a1) without catalyst and the catalytic hydroconversion step (a2) based in particular on sulfur-resistant and selective catalysts suitable for low-temperature operation enables the conversion of the plastic feedstock to be maximized, while minimizing the energy required for the conversion and at the same time minimizing the gas production during the conversion, in order to improve the relative yield of the liquid products of interest.

[0156] This is because the inventors have demonstrated that, by virtue of the combination of these two steps (a1) and (a2), it is surprisingly possible to minimize the yield of gaseous hydrocarbons (i.e. C1 to C6 hydrocarbons) relative to the resulting liquid products at the end of the hydroconversion.

[0157] The choice of catalyst in step (a2), in particular the selectivity provided by the catalyst, also makes it possible to vary the composition of the resulting liquid products according to the intended final use. For example, it may be advantageous to maximize the naphtha fraction for steam cracking applications, or the kerosene fraction for the aviation field, or even the very heavy fraction for bitumen production, for example by selecting a catalyst that is more selective for one or the other of these fractions.

[0158] Catalyst

[0159] The hydroconversion catalyst used in the process according to the invention is a bifunctional type hydrocracking catalyst which combines an acidic function with a hydrogenation-dehydrogenation function and at least one binder matrix.

[0160] Such catalysts are well known in the field of hydrocracking.

[0161] Such hydrocracking catalysts are generally classified based on the nature of their acidic function, in particular catalysts containing an amorphous acidic function of the silica-alumina type and catalysts containing a zeolite-based cracking function, such as zeolite Y or zeolite beta. The hydrocracking catalysts can also be classified according to the main products obtained when they are used in the hydrocracking process (in a conventional hydrocracking process for treating feeds of the vacuum gas oil or gas oil type, the two main products are generally middle distillates and naphtha).

[0162] The hydroconversion catalyst used in the process according to the invention contains at least one hydrogenation-dehydrogenation element selected from the non-noble elements of groups VIB and VIII of the periodic table, either alone or as a mixture, and a porous support containing a porous mineral matrix and at least one zeolite, and preferably consisting of a porous mineral matrix and at least one zeolite.

[0163] At least due to the nature of the hydrogenation-dehydrogenation elements it contains, the hydroconversion catalyst is sulfur-tolerant. It can therefore withstand the presence of sulfur from sulfur-based radical sources, particularly in the case where steps (a1) and (a2) are carried out in the same reactor.

[0164] Depending on the choice of catalyst, it is possible to promote the hydrotreating reactions of the heteroatoms contained in the feed.

[0165] The hydroconversion catalyst advantageously contains:

[0166] - at least one hydrogenation-dehydrogenation element selected from the non-noble elements of groups VIB and VIII, expressed as the weight of the oxide, between 0.1% by weight and 50% by weight relative to the total weight of the catalyst;

[0167] - a porous support between 0.1% by weight and 99.9% by weight relative to the total weight of the catalyst, the support comprising between 0.1% by weight and 80% by weight of zeolite, preferably between 2% by weight and 70% by weight, and very preferably between 3% by weight and 60% by weight, relative to the total weight of the support, and a porous mineral matrix (binder) between 0.1% by weight and 99.9% by weight, expressed as the weight of the oxide, relative to the total weight of the support;

[0168] - At least one element selected from phosphorus, boron and silicon, expressed as the weight of the oxide, is between 0% by weight and 20% by weight, preferably between 0.1% by weight and 20% by weight, based on the total weight of the catalyst (by weight of the oxide P 2 O 5 for phosphorus, by weight of the oxide B 2 O 3 for boron, and by weight of the oxide SiO 2 for silicon);

[0169] - At least one Group VIIA element between 0% by weight and 20% by weight, preferably between 0.1% and 20%;

[0170] - At least one Group VIIB element between 0% by weight and 20% by weight, preferably between 0.1% and 20%,

[0171] - At least one Group VB element between 0% by weight and 60% by weight, preferably between 0.1% and 60%,

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

[0173] Hydrogenation - dehydrogenation function

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

[0175] Advantageously, the hydroconversion catalyst of the process according to the invention does not contain noble metals, which would make the catalyst sensitive to certain compounds such as sulfur compounds and impair its activity.

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

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

[0178] The following metal combinations are preferred: 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 element in the catalyst is advantageously an oxide between 0 and 20% by weight, preferably between 0.5% and 10% by weight, and very preferably between 1% and 8% by weight relative to the total weight of the catalyst.

[0180] The content of the Group VIB element in the catalyst is advantageously an oxide between 1% and 50% by weight, preferably between 5% and 40% by weight, and more preferably between 10% and 35% by weight relative to the total weight of the catalyst.

[0181] Preferably, the hydroconversion catalyst used in the process according to the invention further contains a promoter element selected from phosphorus, boron and silicon, very preferably phosphorus.

[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 2 O 5 , preferably between 0.1% and 10% by weight of oxide P 2 O 5 , and more preferably between 0.2% and 6% 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 porous support containing at least one porous mineral matrix and at least one zeolite, and preferably consisting of at least one porous mineral matrix and at least one zeolite.

[0189] Preferably, the zeolite is selected from 10MR zeolites (zeolites having channels with pore diameters defined by rings containing 10 oxygen atoms) or 12MR zeolites (zeolites having channels with pore diameters defined by rings containing 12 oxygen atoms).

[0190] According to one or more preferred embodiments, the hydroconversion catalyst support comprises at least one zeolite selected from zeolites belonging to the FAU type (any other name for zeolite X, Y, USY, and dealuminated Y zeolite), BEA, ISV, IWR, IWW, MEI, UWY, MEL, MTW, MTT, MSE, FER, or MFI type, preferably selected from FAU or BEA type zeolites.

[0191] Without limiting the list of possible choices, some examples of zeolites from the aforementioned families are mentioned below: ZSM-5 (MFI), ZSM-11 (MEL), ZSM-12 (MTW), ZSM-23 (MTT), ZSM-35 (FER), ZSM-48 (MRE), CP841E, CP814C, CP811C-300, HSZB25, HSZB30, HSZB150, HSZ931, HSZ940, HSZ980 (BEA), or Y82, Y84, CP300-56, CBV712, CBV720, CBV760, CBV780, CBV500, HSZ320, HSZ330, HSZ331, HSZ385, HSZ350, HSZ360, HSZ390, HSZ341, or HSZ371 (FAU or USY).

[0192] Preferably, the support comprises USY zeolite and / or beta zeolite, either alone or as a mixture, which preferably comprises USY zeolite and is preferably composed of USY zeolite. All methods for preparing zeolites can be used to produce the zeolites used in the preparation of this catalyst.

[0193] According to one or more embodiments, the hydroconversion catalyst support comprises USY zeolite and beta zeolite.

[0194] According to one or more embodiments, the hydroconversion catalyst support comprises at least one zeolite selected from zeolite ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48, and ZBM-30.

[0195] The zeolites are advantageously defined in the classification "Atlas of Zeolite Framework Types, 6th Revised Edition", Ch. Baerlocher, L.B. McCusker, D.H. Olson, 6th Edition, Elsevier, 2007, Elsevier.

[0196] These names USY, Beta, ZSM-12, etc. are common in the literature, but they do not limit the characteristics of the zeolites used in the method of the present invention to such names.

[0197] The USY zeolite that can be used in the catalyst support of the method according to the present invention advantageously has at least one of the following characteristics:

[0198] - a specific surface area measured by physical adsorption of nitrogen according to the B.E.T. method of greater than 500 m 2 / g, preferably between 600 m 2 / g and 1100 m 2 / g, and more preferably still between 750 m 2 / g and 1000 m 2 / g;

[0199] - a mesopore volume between 0.05 ml / g and 0.9 ml / g, preferably between 0.08 ml / g and 0.7 ml / g, and more preferably still between 0.1 ml / g and 0.6 ml / g;

[0200] - having lattice parameters (which can be measured by X-ray diffraction according to standard ASTM 03942-80) between preferably between more preferably between ;

[0201] - a Si / Al molar ratio between 2 and 300, preferably between 2.5 and 150, and more preferably still between 2.5 and 100 (which can be characterized by semi-quantitative X-ray fluorescence (for Si content) and ICP (inductively coupled plasma)).

[0202] The β-zeolite that can be used in the catalyst support of the method according to the present invention advantageously has a Si / Al atomic molar ratio between 5 and 300, preferably between 6 and 200, and more preferably between 6 and 100.

[0203] The β-zeolite used may also have a specific surface area measured by physical adsorption of nitrogen using the B.E.T. method of greater than 500 m 2 / g, preferably between 550 m 2 / g and 900 m 2 / g, more preferably still between 550 m 2 / g and 800 m 2 / g, and a mesopore volume between 0.05 mL / g and 0.9 mL / g, preferably between 0.1 mL / g and 0.9 mL / g, and more preferably still between 0.15 mL / g and 0.85 mL / g.

[0204] Preferably, based on the weight of the support of the catalyst, the total weight content of the zeolite in the support is between 0.1% by weight and 80% by weight, preferably between 2% by weight and 70% by weight, and more preferably between 3% by weight and 60% by weight.

[0205] When the support comprises a mixture of USY zeolite and beta zeolite, the weight ratio of USY to beta is preferably between 1 and 20, more preferably between 1.5 and 18, and even more preferably between 2 and 15.

[0206] The porous mineral matrix used in the catalyst support, also known as the binder matrix or binder, advantageously consists of at least one refractory oxide preferably selected from alumina, silica-alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or as a mixture. Preferably, the porous mineral matrix is selected from alumina and silica-alumina, either alone or as a mixture. Even more preferably, the porous mineral matrix is alumina. Alumina can advantageously be provided in all its forms known to those skilled in the art. For example, alumina is selected from alpha, rho, chi, kappa, eta, gamma, theta, and delta alumina, preferably from gamma, theta, and delta alumina, and more preferably is gamma alumina, such as boehmite.

[0207] In the case where the support comprises alumina, the weight content of alumina in the catalyst support can be between 1 wt% and 99.9 wt%, preferably between 30 wt% and 98 wt%, and even more preferably between 40 wt% and 97 wt% based on the total weight of the support.

[0208] According to one or more embodiments, the support of the hydroconversion catalyst further comprises amorphous silica-alumina. Such a catalyst support is referred to as a "composite" support. These composite supports are known to be composed of a mixture of a highly acidic zeolite (such as USY zeolite) and a medium acidic amorphous matrix (such as silica-alumina) and have intermediate activity and selectivity. The acid function of the catalyst is mainly based on the mixture of zeolite and amorphous silica-alumina in the support. The weight content of amorphous silica-alumina in the support can be between 1 wt% and 99.9 wt%, preferably between 30 wt% and 98 wt%, and preferably between 40 wt% and 97 wt% based on the total weight of the support. In the case of using such a catalyst with a composite support, the support can further comprise a binder other than amorphous silica-alumina, which can be selected from alumina, clay, titanium oxide, boron oxide, and zirconia, either alone or as a mixture, and is preferably alumina. Alumina can advantageously be in any form known to those skilled in the art. Very preferably, alumina is selected from alpha, rho, chi, kappa, eta, gamma, theta, and delta alumina, preferably from gamma, theta, and delta alumina. In the case where the support comprises alumina, the weight content of alumina in the catalyst support can be between 1 wt% and 70 wt%, preferably between 2 wt% and 60 wt%, and even more preferably between 5 wt% and 50 wt% based on the total weight of the support.

[0209] Preferably, the porous support containing at least one zeolite advantageously has a total pore volume between 0.15 cm 3 .g -1 and 1.2 cm 3 .g -1 , preferably between 0.18 cm 3 .g -1 and 1.1 cm 3 .g -1 , and very preferably between 0.2 cm 3 .g -1 and 1.0 cm 3 .g -1 .

[0210] The BET surface area of the support containing at least one zeolite is advantageously greater than 150 m 2 .g -1 , preferably between 150 m 2 .g -1 and 900 m 2 .g -1 , very preferably between 180 m 2 .g -1 and 850 m 2 .g -1 , and even more preferably between 200 m 2 .g -1 and 800 m 2 .g -1 .

[0211] The support is advantageously provided in the form of beads, extrudates, pellets or irregular and non-spherical agglomerates, the specific shape of which can be produced by a crushing step. The support typically has millimetric dimensions, preferably between 0.4 mm and 4.4 mm.

[0212] The catalyst may also additionally 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 functions selected from carboxyl, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide functions, or compounds containing a furan ring or sugar.

[0213] The content of the organic compound containing oxygen and / or nitrogen and / or sulfur on the catalyst is between 1% by weight and 30% by weight, preferably between 1.5% by weight and 25% by weight, and more preferably between 2% by weight and 20% by weight, relative to the total weight of the catalyst.

[0214] The preparation of the catalyst is known to those skilled in the art and generally comprises the steps of impregnating a Group VIII and / or Group VIB metal and optionally phosphorus and / or an organic compound on a support comprising at least one zeolite, followed by a drying operation and then optionally calcination to obtain the metal in its oxide form. Before its use in a hydrocracking process of hydrocarbon fractions, the catalyst is generally subjected to sulfidation to obtain the metal in its sulfided or partially sulfided form.

[0215] When an organic compound is present, the catalyst preferably does not undergo calcination during its preparation, i.e., 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, in the presence or absence of water.

[0216] Alternatively, the catalyst can undergo a calcination step during its preparation, i.e., the impregnated catalyst precursor undergoes a heat treatment step in an inert atmosphere or in an oxygen-containing atmosphere, in the presence or absence of water, at a temperature between 200 °C and 1000 °C, and preferably between 250 °C and 750 °C, generally for between 15 minutes and 10 hours.

[0217] An example of the catalyst used in step (a2) comprises at least one Group VI metal and at least one Group VIII non-noble metal, USY zeolite, and an alumina binder, and is preferably composed of them.

[0218] Another example of the catalyst used in step (a2) comprises nickel, molybdenum, USY zeolite, preferably composed of nickel, molybdenum, USY zeolite, optionally as a mixture with beta zeolite, alumina, and optionally phosphorus.

[0219] Operation of steps (a1) and (a2)

[0220] Equipment items

[0221] Steps (a1) and (a2) can be carried out in the same reactor or in two separate reactors.

[0222] Preferably, steps (a1) and (a2) are carried out in the same reactor.

[0223] According to one or more embodiments, steps (a1) and (a2) are carried out in the same ebullated bed reactor.

[0224] According to one or more embodiments in which steps (a1) and (a2) are carried out in two separate reactors, steps (a1) and (a2) are carried out in two separate ebullated bed reactors.

[0225] According to one or more embodiments in which 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.

[0226] Several reactors arranged in series or in parallel can be used to carry out step (a1) and / or step (a2).

[0227] When steps (a1) and (a2) are carried out in the same reactor, the hydroconversion is carried out "one pot", i.e., the hydroconversion reactions of steps (a1) and (a2) take place concomitantly in the same reaction medium. Carrying out steps (a1) and (a2) in the same reactor particularly makes it possible to limit the number of items of equipment required for the hydroconversion and to simplify the operation.

[0228] According to the embodiment in which steps (a1) and (a2) are carried out in separate reactors, reactors of different technologies can be used, for example, for step (a1), a two-phase (gas and liquid) reactor or a three-phase (gas, liquid and solid) reactor of the fluidized bed or slurry type, where the solid phase is not the catalyst but the plastic feedstock, and for step (a2), a three-phase reactor of the fixed bed type. In this way, the process has greater flexibility particularly in terms of introducing the plastic feedstock into the first hydroconversion reactor.

[0229] Carrying out steps (a1) and (a2) in two separate reactors also allows for greater flexibility in terms of operating conditions, such as the possibility of operating at different pressures, for example, the pressure in step (a1) being higher than the pressure in step (a2), or the possibility of operating at different temperatures or differently controlled temperatures, for example, using a fluidized bed reactor in step (a1) and a fixed bed reactor in step (a2).

[0230] 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). This separation can have the advantage of using a smaller or a second reactor operating at a longer residence time (the reactor for step (a2)). This also has the advantage of being able to use less catalyst, particularly in the case of a fluidized bed reactor.

[0231] Steps (a1) and (a2) of the process according to the invention use reactors which can be hydroconversion reactors.

[0232] 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., the reduction of the boiling range) in the presence of hydrogen and a hydroconversion catalyst. A hydroconversion reactor typically includes at least one feed port through which the feedstock and hydrogen can be introduced and at least one discharge port through which the reformed material can be withdrawn. Specifically, hydroconversion reactors are also characterized by having sufficient thermal energy to break larger molecules into smaller molecules by thermal decomposition. Generally, 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 behave like a homogeneous phase), ebullated bed reactors (fluidized 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 over a fixed bed of supported catalyst and hydrogen typically flows concurrently with the liquid, but may flow countercurrently in some cases).

[0233] Step (a1), if carried out in a reactor separate from step (a2), can be carried out in any type of reactor corresponding to the above definition of a hydroconversion reactor, but without a catalyst.

[0234] According to one or more embodiments of the present invention, as described above for optional step (a0), the plastic feedstock is introduced into the first hydroconversion reactor by extrusion and thus in a substantially liquid form. In such cases, a hydroconversion reactor of the fixed bed, moving bed, or ebullated bed reactor type as mentioned above can be used.

[0235] 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, for example, a plastic feedstock that is substantially in liquid form at the end of extrusion as already mentioned, and is also better suited for cases where the plastic feedstock is introduced in the form of solid particles (optionally suspended in a liquid, for example, also as described above for optional step (a0)).

[0236] The ebullated bed hydroconversion reactor contains a hydroconversion catalyst retained in the reactor. According to one or more embodiments of the present invention, one or more hydroconversion reactors that can operate as an ebullated bed in series and / or in parallel can be used for H - Oil TMProcesses, such as, for example, those described in patent US 4 521 295 or US 4 495 060 or US 4 457 831 or US 4 354 852, in the paper AIChE, March 19 - 23, 1995, Houston, Texas, paper No. 46d, “Second generation ebullated bed technology”, or in chapter 3.5, “Hydroprocessing and Hydroconversion of Residue Fractions” of the work “Catalysis by Transition Metal Sulfides” published by Technip in 2013. According to these embodiments, the reactor operates as a “fluidized bed” ebullated bed. The reactor advantageously includes a recycle pump capable of maintaining a porous supported solid hydroconversion catalyst as an ebullated bed by continuous recycle of at least a portion of the liquid fraction withdrawn at the upper part of the reactor and reinjected at the lower part of the reactor.

[0237] The ebullated bed reactor preferably includes at least one feed hole located at or near the lower part of the reactor through which the plastic feedstock is introduced together with hydrogen, and a discharge hole located at or near the upper part of the reactor through which the conversion product is withdrawn. The reactor preferably further includes an inlet and an outlet for the supported catalyst connected to means for injecting and withdrawing the supported catalyst.

[0238] The ebullated bed reactor further includes an expanded catalyst zone containing a porous supported catalyst. The ebullated 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 feedstock is continuously circulated in the ebullated bed reactor from the upper zone without supported catalyst to the lower zone without supported catalyst via a recycle conduit in communication with an ebullating pump. Preferably, a funnel-shaped recycle pan is located at the upper part of the recycle conduit through which the feedstock is drawn from the upper zone without supported catalyst. The internally recycled feedstock is mixed with “fresh” feedstock and additional hydrogen.

[0239] Compared with other types of reactors, such as fixed-bed reactors (which may require the reactor to be stopped to replace spent catalyst, mainly due to deactivation by deposition of metals contained in the feedstock (e.g., in the form of vanadium sulfide and nickel sulfide) and due to coke deposition), the device for injecting and removing catalyst enables continuous replacement of the supported catalyst, which constitutes one of the advantages of fluidized-bed technology. The spent catalyst removed from the reactor can be sent to a regeneration zone, where the carbon and sulfur contained therein are removed. It is also possible to send the spent catalyst removed from the reactor to a rejuvenation zone, where most of the deposited metals are removed, and then send the spent and rejuvenated catalyst to the regeneration zone, where the carbon and sulfur contained therein are removed. The regenerated or rejuvenated catalyst can then be reintroduced into the reactor, optionally in combination with fresh catalyst, through the device for injecting catalyst.

[0240] This removal of catalyst and this additional introduction can be carried out, for example, daily. Generally, the device for injecting and removing supported catalyst comprises at least one tube that emerges in the expansion zone of the supported catalyst in the reactor, for introducing fresh (and / or regenerated and / or rejuvenated) supported catalyst into the expansion zone of the supported catalyst in the reactor and removing spent catalyst from said zone. The introduction and removal can be carried out with the same pipe or by means of separate pipes, thus requiring at least two pipes, namely an injection pipe for injecting supported catalyst into the reactor and a pipe for removing spent catalyst. By this continuous replacement of catalyst, fluidized-bed technology is ultimately able to increase the time between two stoppages of the conversion process.

[0241] Due to the supported catalyst being kept agitated by significant recirculation of the liquid, the hydroconversion reactor as a fluidized bed exhibits a low and constant pressure drop across the reactor, and the reaction heat release is rapidly averaged over the catalyst bed, so it is almost isothermal and does not require injection of a cooling stream (quench).

[0242] Operating conditions

[0243] The hydroconversion process according to the invention is carried out in each reactor or in a single reactor at an absolute pressure between 1 MPa and 38 MPa, at a temperature greater than or equal to 200 °C and less than 400 °C, at a space velocity relative to each reactor between 0.05 h -1 to 10 h -1 and at a hydrogen quantity between 50 Sm 3 / m 3 to 5000 Sm 3 / m 3 .

[0244] It is to be understood that when implementing the embodiments involving a fixed bed, the temperature in these steps is the temperature at the start of the operation, also known as the "start of operation" temperature. In the case of other types of reactors, such as fluidized bed reactors, there is no concept of a start of operation temperature as the temperature remains substantially constant during operation. However, it can be considered that the operating temperatures given for these steps (a1) and (a2) are in all cases the temperature at the start of operation, which remains the same during operation for the case of a fluidized bed reactor, for example.

[0245] In the case of a fixed bed reactor, HSV is typically expressed as the ratio of the volume flow rate of the feedstock (preferably a liquid feedstock) measured under standard temperature and pressure conditions to the volume of the catalyst loaded into the reactor.

[0246] In the case of a fluidized bed reactor, HSV is typically expressed as the ratio of the volume flow rate of the feedstock (preferably a liquid feedstock) measured under standard temperature and pressure conditions to the volume of the reactor.

[0247] Therefore, these two steps (a1) and (a2) are carried out under the above conditions.

[0248] According to one or more embodiments, steps (a1) and (a2) are implemented as follows:

[0249] - at an absolute pressure between 2 MPa and 25 MPa, preferably between 3 and 20 MPa,

[0250] - at a temperature greater than or equal to 250 °C and less than 400 °C, preferably greater than or equal to 300 °C and less than 400 °C, more preferably greater than or equal to 320 °C and less than 400 °C, more preferably greater than or equal to 330 °C and less than 390 °C, for example at 380 °C,

[0251] - at a space velocity with respect to each reactor between 0.1 h -1 and 10 h -1 preferably between 0.1 h -1 and 5 h -1

[0252] - between 50 Sm 3 / m 3 and 5000 Sm 3 / m 3 preferably between 100 Sm 3 / m 3 and 2000 Sm 3 / m 3 and very preferably between 200 Sm 3 / m 3 and 1000 Sm 3 / m 3 ​at a hydrogen content therebetween.

[0253] According to one or more other embodiments, at least one fluidized bed reactor is used to carry out step (a1) or steps (a1) and (a2), which is carried out at a space velocity, relative to the volume of each reactor, between 0.15 h -1 and 2 h -1 and more preferably between 0.15 h -1 and 1 h -1 therebetween.

[0254] According to one or more other embodiments, at least one fluidized bed reactor is used to carry out step (a1) or steps (a1) and (a2), and the total HSV, i.e., the ratio of the flow rate of the liquid feedstock in step (a1) measured under standard temperature and pressure conditions to the total volume of the reactors in steps (a1) and (a2), is between 0.05 h -1 and 0.09 h -1 therebetween.

[0255] Operating at a relatively low temperature below 400 °C makes the method economical in terms of energy as well as operating and investment costs, especially compared to other hydroconversion processes at higher temperatures or other technologies such as pyrolysis. Examples

[0256] The following examples are intended to show certain performance qualities of the method according to the invention compared to methods according to the prior art.

[0257] Examples 1 to 4 are not according to the invention. Examples 5 and 6 are according to the invention.

[0258] In the following examples, a polypropylene plastic raw material (weight average molecular weight MW = 456000 Da and number average molecular weight Mn = 76800 Da) was introduced in the form of solid particles into an autoclave reactor, hereinafter also referred to as a batch reactor.

[0259] The operating conditions were as follows:

[0260] Reaction temperature 380 °C,

[0261] H 2 Partial pressure: 7 MPa,

[0262] Duration of the test: 150 minutes,

[0263] Stirring speed: 1400 rpm.

[0264] Procedure for all the following examples: Charge the batch reactor with plastic raw materials, a catalyst pre-activated by a vulcanization procedure known to those skilled in the art, and DMDS (when used). Close the reactor, purge it with nitrogen and then with hydrogen, and then pressurize it with hydrogen to a pressure of about 3 MPa. Subsequently, heat the reactor to the test temperature. Start stirring at 300 °C. When the reaction temperature is reached, by adding H 2 Immediately adjust the pressure in the reactor to the target value. At this time, count down the reaction time. At the end of the duration of this experiment, 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.

[0265] The results regarding the conversion products and the hydroconversion performance qualities are summarized in Table 1 below.

[0266] Example 1: Hydroconversion method without a sulfur-based radical source and without a catalyst (not according to the present invention)

[0267] In the absence of addition of a sulfur-based radical source or a catalyst, no conversion of the plastic raw materials was observed: 100% of the plastic raw materials were solids at the end of the test.

[0268] Example 2: Hydroconversion method using a sulfur-based radical source containing 4% by weight of sulfur and without a catalyst (not according to the present invention)

[0269] In this Example 2, the sulfur-based radical source DMDS was added in a proportion of 4% by weight of sulfur relative to the weight of the plastic raw materials. A conversion of 93.5% of the plastic raw materials (yield of non-solid products) was observed relative to the raw materials, and the yield of the liquid products was 93% by weight relative to the raw materials.

[0270] The yields of the products and the composition of the liquid products are given in Table 1.

[0271] Example 3: Hydroconversion method without a sulfur-based radical source and using catalyst C1 (not according to the present invention)

[0272] The mass ratio of catalyst C1 relative to the raw materials was 10% catalyst. Catalyst C1 is a catalyst composed of 16.2% by weight of MoO relative to the catalyst and 2.9% by weight of NiO on a support, and the support contains 30% by weight relative to the support in an alumina matrix of USY zeolite having 3 a lattice parameter of. Obtain a conversion of 7% of the plastic raw materials relative to the raw materials. In addition, all the liquid products belong to the super-heavy fraction with an initial boiling point greater than or equal to 740 °C.

[0273]

[0274] ​The yields of the products and the composition of the liquid products are given in Table 1.

[0275] Example 4: Hydroconversion process using a sulfur-based radical source containing 1% by weight of sulfur and catalyst C1 (not according to the invention)

[0276] The mass ratio of catalyst C1 to the feedstock is 10% catalyst.

[0277] In this Example 4, the sulfur-based radical source DMDS was added in a proportion of 1% by weight of sulfur relative to the weight of the plastic feedstock.

[0278] A conversion of the plastic feedstock of 58% by weight relative to the feedstock was obtained, as well as a low yield of liquid products. In addition, all products belong to the super-heavy fraction with an initial boiling point greater than or equal to 740 °C.

[0279] The yields of the products and the composition of the liquid products are given in Table 1.

[0280] Example 5: Hydroconversion process using a sulfur-based radical source containing 4% by weight of sulfur and catalyst C1 (according to the invention)

[0281] The mass ratio of catalyst C1 to the feedstock is 10% catalyst.

[0282] In this Example 5, the sulfur-based radical source DMDS was added in a proportion of 4% by weight of sulfur relative to the weight of the plastic feedstock.

[0283] Conversion of the plastic feedstock was observed, where the yield of non-solid products was 96% by weight relative to the feedstock, including a yield of 93% by weight of liquid products and a yield of 3% by weight of gas products.

[0284] Compared with Example 2 using the same sulfur-based radical source in the same proportion but without a catalyst, the following differences were noted for the following fractions: heavy products (370 °C - 740 °C) - 16 percentage points, gas oil fraction (250 °C - 370 °C) + 3 percentage points, kerosene (150 °C - 250 °C) + 9 percentage points, naphtha (80 °C - 150 °C) + 4 percentage points, indicating a greater selectivity for the gas oil, kerosene and naphtha fractions that can be more easily upgraded.

[0285] Compared with Example 3 without a sulfur radical source but using catalyst C1, a much higher conversion was noted and the following differences for the following fractions: super-heavy products with an initial boiling point greater than or equal to 740 °C - 76 percentage points, products with a final boiling point below 740 °C (including upgradable fractions) + 76 percentage points.

[0286] The yields of the products and the composition of the liquid products are given in Table 1.

[0287] Example 6: Hydroconversion process using a sulfur-based radical source containing 4% by weight of sulfur and catalyst C2 (according to the present invention)

[0288] The mass ratio of catalyst C2 to the feedstock is 10% catalyst.

[0289] Catalyst C2 is a catalyst composed of 20% by weight of MoO relative to the catalyst on a support 3 and 3.8% by weight of massive NiO, and the support contains 16% by weight of USY zeolite having a lattice parameter and 6% by weight of β zeolite having a Si / Al molar ratio of 27 in an alumina matrix.

[0290] In this Example 6, the sulfur-based radical source DMDS was added in a proportion of 4% by weight of sulfur relative to the weight of the plastic feedstock.

[0291] Conversion of the plastic feedstock was observed, where the yield of non-solid products was 98% by weight relative to the feedstock, including a yield of 86% by weight of liquid products and a yield of 12% by weight of gas products.

[0292] Compared with Example 2 using the same proportion of the same sulfur-based radical source but without a catalyst, the following differences were noted for the following fractions: very heavy products (540 °C +) - 44 percentage points, heavy products (370 °C - 540 °C) - 2 percentage points, gas oil fraction (250 °C - 370 °C) + 6 percentage points, kerosene (150 °C - 250 °C) + 16 percentage points, naphtha (80 °C - 150 °C) + 13 percentage points, indicating a greater selectivity for the kerosene and naphtha fractions that can be more easily upgraded.

[0293] Compared with Example 5 using the same proportion of the same sulfur-based radical source but using a different catalyst, the conversion to non-solid products was equally good, the amount of gas produced, although higher, was still acceptable compared to the liquid products, and the selectivity for light fractions (540 °C -), especially for the kerosene fraction (150 °C - 250 °C) and the naphtha fraction (80 °C - 150 °C), was higher.

[0294] The yields of the products and the composition of the liquid products are given in Table 1.

[0295] A summary of the main data of the said examples, including the product yields and the composition of the liquid products, is given in Table 1 below.

[0296] Table 1

[0297]

Claims

1. A method for hydroconverting a plastic raw material, which comprises the following steps: (a1) A non-catalytic hydroconversion step of the raw material in the presence of hydrogen in contact with a radical source, said source containing sulfur and introduced thereto such that the sulfur content is between 3% by weight and 20% by weight relative to the weight of the plastic raw material, to produce a first conversion product; (a2) A catalytic hydroconversion step of the first conversion product in the presence of hydrogen in contact with at least one hydroconversion catalyst, said hydroconversion catalyst comprising at least one hydrogenation-dehydrogenation element selected from the non-noble metal elements of Groups VIB and VIII of the Periodic Table, either alone or as a mixture, and a porous support containing a porous mineral matrix and at least one zeolite, The steps (a1) and (a2) are carried out at an absolute pressure between 1 MPa and 38 MPa, at a temperature greater than or equal to 200 °C and less than 400 °C, at a space velocity relative to each hydroconversion reactor between 0.05 h -1 and 10 h -1 and at a hydrogen amount between 50 Sm 3 / m 3 and 5000 Sm 3 / m 3 respectively.

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 zeolite of the hydroconversion catalyst support is selected from FAU-type zeolites, preferably FAU-type zeolites selected from zeolite X, Y, USY, dealuminated Y, BEA, ISV, IWR, IWW, MEI, UWY, MEL, MTW, MTT, MSE, FER and MFI, and the at least one zeolite is preferably selected from FAU or BEA-type zeolites.

6. The hydroconversion method according to any one of the preceding claims, wherein the catalyst support comprises USY zeolite and / or β zeolite.

7. The hydroconversion method according to any one of the preceding claims, wherein the hydroconversion catalyst support comprises at least one zeolite selected from zeolite ZSM-12, IZM-2, ZSM-22, ZSM-23, SAPO-11, ZSM-48 and ZBM-30.

8. The hydroconversion method according to any one of the preceding claims, wherein the hydroconversion catalyst comprises: - at least one hydrogenation-dehydrogenation element selected from the non-noble metal elements of Groups VIB and VIII, in an amount between 0.1% by weight and 50% by weight, expressed as the weight of the oxide, relative to the total weight of the catalyst; - a porous support in an amount between 0.1% by weight and 99.9% by weight relative to the total weight of the catalyst, said support comprising zeolite in an amount between 0.1% by weight and 80% by weight relative to the total weight of the support and a porous mineral matrix in an amount between 0.1% by weight and 99.9% by weight, expressed as the weight of the oxide, relative to the total weight of the support; - At least one element selected from phosphorus, boron and silicon, expressed as the weight of the oxide, is between 0% by weight and 20% by weight, preferably between 0.1% by weight and 20% by weight, based on the total weight of the catalyst. - At least one Group VIIA element is between 0% by weight and 20% by weight, preferably between 0.1% and 20%. - At least one Group VIIB element is between 0% by weight and 20% by weight, preferably between 0.1% and 20%. - At least one Group VB element is between 0% by weight and 60% by weight, preferably between 0.1% and 60%. The percentages are expressed as weight percentages relative to the total mass of the catalyst, and the sum of the percentages of the elements constituting the catalyst is equal to 100%.

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

10. 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, preferably molybdenum, as hydrogenation-dehydrogenation elements.

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 of the formula (CH 3 S) 2 ), thiols and polysulfides such as ditertiary nonyl polysulfide, individually 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, wherein the sulfur content in step (a1) is between 3% by weight and 15% by weight, preferably between 3% by weight and 10% by weight of the feedstock, based on the weight of the plastic feedstock.

13. The hydroconversion process according to any one of the preceding claims, which further comprises: (a0) A preliminary step of conditioning the feedstock for introduction into a reactor for carrying out at least the first step (a1), the step (a0) comprising: - feeding the plastic feedstock in solid particle form, preferably together with a plastic diluent, into an extruder, where it is gradually heated to a temperature above the melting point of the plastic feedstock and is under the pressure of the first hydroconversion reactor during conveyance, and - introducing the extruded plastic feedstock into the reactor.

14. 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 the plastic feedstock preferably 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 ethylene / propylene copolymers.

15. The hydroconversion process according to any one of the preceding claims, wherein steps (a1) and (a2) are carried out at an absolute pressure between 2 MPa and 25 MPa and at a temperature greater than or equal to 300 °C and less than 400 °C.

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