Method for the fixed-bed treatment of a heavy fossil-based feedstock comprising a fraction of plastic pyrolysis oil

Abstract

Process for the treatment of a feedstock comprising a fraction of plastic and / or tyre and / or solid recovered fuel pyrolysis oil and a heavy fraction of hydrocarbons of fossil origin, said fraction of pyrolysis oil constituting less than 50% by weight of said feedstock, said process comprising:a) a hydrodemetallization stage in a fixed bed reaction section comprising at least two permutable reactors which is fed at least by said feedstock and a gas stream comprising hydrogen, in the presence of a hydrodemetallization catalyst,b) a hydrotreating stage in a reaction section comprising at least one fixed bed reactor, said section being fed by said effluent resulting from stage a) and optionally a gas stream comprising hydrogen, in the presence of a hydrotreating catalyst,c) a stage of separation of the effluent resulting from stage b).

Description

TECHNICAL FIELDThe present invention relates to the field of the hydroconversion of feedstocks predominantly comprising a heavy fraction of hydrocarbons of fossil origin and a minor fraction of plastic and / or tyre and / or solid recovered fuel (SRF) pyrolysis oil, which is laden with impurities. The heavy fraction of hydrocarbons is a heavy oil feedstock of atmospheric residue and / or vacuum residue type.In particular, the present invention relates to a process for the treatment of such a mixed feedstock in a fixed bed for the purpose of producing materials of higher quality, having a lower boiling point, for example for the purposes of the production of fuels or of chemicals, while making possible the capture of the impurities of the plastic and / or tyre and / or solid recovered fuel (SRF) pyrolysis oil.PRIOR ARTFor several years, the appearance has been seen, within fuel and chemical industries, of processes incorporating products other than conventional petroleum products, for example waste, such as plastics or spent oils, as supplement or replacement for products of fossil origin.

[0004] In particular, plastics resulting from collection and sorting industries can undergo a stage of pyrolysis in order to obtain, inter alia, pyrolysis oils. These plastics pyrolysis oils are generally incinerated in order to generate electricity and / or used as fuel in industrial or urban heating boilers.

[0005] Spent tyres often undergo the same treatment.

[0006] Solid recovered fuels (SRFs), also called refuse-derived fuel (RDF), are solid non-hazardous wastes prepared with a view to energy upgrading, whether they originate from household and similar waste, from waste from economic activities or from waste from construction and demolition. SRFs are generally a mixture of any combustible waste, such as spent tyres, food by-products (fats, animal meal, and the like), viscose and wood waste, light fractions resulting from shredders (for example from used vehicles, electrical and electronic equipment (WEEE)), household and commercial waste, residues from the recycling of various types of waste, including certain municipal wastes, plastic waste, textiles or wood, inter alia. SRFs generally contain plastic waste. Nowadays, SRFs are mainly upgraded as energy. They can be used directly as substitutes for fossil fuels in co-incineration facilities (coal and lignite power stations, cement works, lime kilns) or in household waste incineration units, or indirectly in pyrolysis units dedicated to energy upgrading: SRF pyrolysis oils are thus generally burned to generate electricity, indeed even are used as fuel in industrial or urban heating boilers.

[0007] Plastic and / or tyre and / or SRF pyrolysis oils can also be upgraded, optionally via refining processes, to produce fuels, for example petrol or diesel, and / or chemicals, such as olefins, for the production of various polymers of the chemical industry.

[0008] However, this route for the upgrading of plastic and / or tyre and / or SRF pyrolysis oils is confronted with the problems generated by the specific composition of these oils, in particular by the impurities which they contain, the composition of these oils being itself related to the diversity of the components of the plastic waste, tyres and SRFs.

[0009] This is because plastic waste, tyres or SRFs are generally mixtures of several polymers, for example mixtures of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride and polystyrene. In addition, depending on the uses, plastics may contain other compounds in addition to the polymers, such as plasticizers, pigments, dyes or also polymerization catalyst residues, as well as other highly varied organic and mineral impurities, originating from separation operations of sorting centres, the selectivity of which operation may not be 100%.

[0010] The oils resulting from the pyrolysis thus generally comprise many diolefins and impurities, in particular metals, silicon, or also halogenated compounds, in particular chlorine-based compounds, heteroelements, such as sulfur, oxygen and nitrogen, insolubles, at contents which are often high and which can be incompatible with some refining units.

[0011] The treatment of these oils can present operability problems and in particular problems of corrosion, coking or catalytic deactivation, or also incompatibility problems in the applications of the target polymers. The presence of diolefins, for example, very often results in problems of instability of the pyrolysis oil which are characterized by the formation of gums. The gums and the insolubles possibly present in the pyrolysis oil can give rise to problems of clogging in the items of equipment.

[0012] One route for removing these impurities contained in plastic and / or tyre and / or SRF pyrolysis oils is to carry out a hydrotreating in the presence of catalysts.

[0013] Application WO2018 / 055555 provides, for example, a very general and relatively complex overall process for the recycling of plastic waste, ranging from the actual stage of pyrolysis of the plastic waste up to a steam cracking stage, which makes it possible to produce products highly upgradable in the petrochemical field, such as olefins and aromatic compounds. The process comprises, inter alia, a stage of hydrocracking of the liquid phase resulting directly from the pyrolysis, preferably in a fixed bed.

[0014] Patent Applications FR 3 107 530, FR 3 113 060 and FR 3 113 061 describe processes for the treatment of a plastic pyrolysis oil comprising, inter alia, a stage of selective hydrogenation of the plastic pyrolysis oil and a hydrotreating in a fixed bed of the hydrogenated effluent. The naphtha cut resulting from a specific separation with water of the hydrotreated effluent, followed by a fractionation of the separated hydrocarbon stream, can be sent to a steam cracker or be used as fuel stock. According to Patent Applications FR 3 113 060 and FR 3 113 061, the process incorporates one or two stages of hydrocracking in a fixed bed after the hydrotreating stage in order to minimize the yield of the heavy cut and to maximize the yield of the naphtha cut by transforming the heavy cut, at least partly, into a naphtha cut by hydrocracking, which is the cut generally favoured for a steam cracking unit.Objectives and Summary of the Invention

[0015] The present invention relates to the field of the upgrading of heavy feedstocks of fossil origin which are difficult to upgrade, such as petroleum residues, which generally contain high contents of impurities, such as metals, sulfur, nitrogen, Conradson carbon and asphaltenes, in order to convert them into lighter products, upgradable as fuels, for example in order to produce petrols, gas oils or bunker fuel oils, or starting materials for the petrochemical industry.

[0016] More particularly, the present invention provides a process for the treatment of a feedstock comprising a heavy fraction of hydrocarbons of fossil origin having an initial boiling point of at least 340° C. and a final boiling point of at least 550° C. and containing sulfur and nitrogen, and a fraction of plastic and / or tyre and / or solid recovered fuel pyrolysis oil, said fraction of pyrolysis oil constituting less than 50% by weight of said feedstock, said process comprising:

[0017] a) a hydrodemetallization stage carried out in a fixed bed reaction section comprising at least two permutable reactors, said section being fed at least by said feedstock and a gas stream comprising hydrogen, in the presence of at least one hydrodemetallization catalyst, at a temperature between 30° and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1,

[0018] b) a hydrotreating stage carried out in a reaction section comprising at least one fixed bed reactor, said section being fed at least by said effluent resulting from stage a) and optionally a gas stream comprising hydrogen, in the presence of at least one hydrotreating catalyst, at a temperature between 30° and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1,

[0019] c) a stage of separation of the effluent resulting from stage b) carried out in a separation section resulting in a gas fraction and at least one liquid product.

[0020] The inventors have demonstrated that, surprisingly, it was possible to incorporate a minor fraction of plastic and / or tyre and / or SRF pyrolysis oil, laden with impurities, in a heavy hydrocarbon feedstock of fossil origin, typically an atmospheric residue or a vacuum residue, conventionally treated in a fixed bed hydroconversion process, thus making possible an optimized treatment of the two difficult feedstocks by efficiently treating the impurities present and by converting the feedstocks into upgradable products.

[0021] The present invention thus provides a process for the hydroconversion of a heavy feedstock of hydrocarbons of fossil origin, in particular of atmospheric residue and / or vacuum residue type, in a fixed bed, said feedstock including a minor fraction of plastic and / or tyre and / or SRF pyrolysis oil, thus making possible the production of fuel stocks and other upgradable hydrocarbons and / or feedstocks appropriate for a steam cracker for the production of olefins and / or aromatics.

[0022] The presence of plastic pyrolysis oil makes possible a major increase in the yield of the IP-180° C. cut while reducing the yields of the heavy cuts. One of the essential aspects of the invention lies in the capacity of the fixed bed reactor(s) to at least partially convert the pyrolysis oil into lighter products by virtue of the combination of a high temperature and of the presence of a catalyst which makes possible the hydrogenation of the unsaturated molecules (olefins or aromatics). The pyrolysis oil co-treatment thus makes it possible to improve the yield of certain cuts which are obtained in the hydrotreated effluent, in particular the petrol cut.

[0023] It has also been demonstrated that, despite the presence of silicon in the pyrolysis oil, the products resulting from the process according to the invention substantially no longer contain it, which indicates that the silicon has been captured by the catalyst or the catalysts. Likewise, the chlorine has been substantially entirely captured and / or converted (into HCl). The products resulting from this stage are thus poor in impurities.

[0024] Another advantage of the invention is to limit the increase in temperature between the inlet and the outlet of a fixed bed reactor, induced in particular by the heat given off by the hydrogenation of the diolefins or olefins contained in particular in the fraction of pyrolysis oil, this heat being in part absorbed by the heavy fraction of hydrocarbons of fossil origin which is treated simultaneously. This results in an optimized process which limits significant recourse to the recycling of effluent and / or to gaseous and / or liquid cooling streams.

[0025] Another objective of the present invention is to produce, by means of the same process, atmospheric distillates (naphtha, kerosene, diesel), vacuum distillates, marine fuels and / or light (C1 to C4) gases.

[0026] According to an alternative form, the stocks of naphtha, kerosene and diesel type can be upgraded in a refinery for the production of fuels for the motor vehicle industry and the aviation industry, such as, for example, premium-grade gasolines, jet fuels and gas oils.

[0027] According to another alternative form, the stocks of naphtha, kerosene and diesel type can be upgraded in a steam cracking unit in order to be able to obtain in particular light olefins which can be used as monomers in the manufacture of polymers.

[0028] According to yet another alternative form, the stocks of naphtha, kerosene and diesel type can be upgraded in a fluidized bed catalytic cracking (FCC for Fluid Catalytic Cracking) unit or also in a hydrocracking unit.

[0029] According to another alternative form, the vacuum distillate can be upgraded in a hydrocracking unit.

[0030] One advantage of the invention is to provide a process coupling conversion and purification of heavy feedstocks of fossil origin for the production of marine fuels having a low sulfur content while upgrading a co-feedstock of pyrolysis oil. The quality requirements for marine fuels are described in Standard ISO 8217. The specification relating to sulfur from now on becomes linked to SOx emissions (Annex VI of the MARPOL Convention of the International Maritime Organization) and is reflected by a recommended sulfur content of less than or equal to 0.5% by weight outside Emission Control Areas (ECAs) in 2020-2025 and less than or equal to 0.1% by weight in Emission Control Areas. Another very restrictive recommendation is the content of sediments after ageing according to ISO 10307-2 (also known under the name of IP390), which must be less than or equal to 0.1% by weight. Also, the viscosity of bunker fuel oils of RMG 380 grade must observe a viscosity limit of less than 380 cSt at 50° C.

[0031] The presence of a pyrolysis oil as co-feedstock in the treatment of a heavy feedstock of fossil origin makes it possible in particular to directly obtain a fuel oil observing the specifications in terms of sulfur, of sediments and of viscosity, without the need to add a flux. Fluxes are generally added to lower the viscosity of a bunker fuel oil in order to meet the viscosity specifications. It is in fact the presence of the pyrolysis oil, which is generally lighter as regards boiling points, which makes it possible to lower the sulfur content and the viscosity in order to achieve the required specifications. The process according to the invention thus makes it possible to directly obtain a bunker fuel oil meeting the required specifications (without the need to add a flux, which is conventionally the case in order to meet the specifications), while simultaneously exhibiting the advantage of being able to upgrade a feedstock which is difficult to upgrade, such as a pyrolysis oil, and to increase the yield of desired distillates.

[0032] According to one or more implementations of the invention, the process according to the invention comprises at least one stage a0) of pretreatment of the fraction of plastic and / or tyre and / or solid recovered fuel pyrolysis oil, said pretreatment stage being carried out upstream of stage a), and comprises an adsorption stage and / or a filtration stage and / or a centrifugation stage and / or an electrostatic separation stage and / or a stage of scrubbing by means of an aqueous solution and / or a gas stripping stage.

[0033] According to one or more implementations of the invention, the fraction of pyrolysis oil constitutes between 1% and 45% by weight of said feedstock, preferably between 2% and 30% by weight of said feedstock, preferably between 2% and 25% by weight of said feedstock.

[0034] According to one or more implementations of the invention, the feedstock is constituted of said fraction of pyrolysis oil and of said heavy fraction of hydrocarbons, said fraction of pyrolysis oil constituting between 1% and 45% by weight, preferably between 2% and 30% by weight, more preferentially between 2% and 25% by weight, of said feedstock and the heavy fraction of hydrocarbons constituting between 55% and 99% by weight, preferably between 70% and 98% by weight, more preferentially between 75% and 98% by weight, of said feedstock.

[0035] According to one or more implementations of the invention, the heavy fraction of hydrocarbons is chosen from the list consisting of an atmospheric residue or a vacuum residue resulting from the atmospheric and / or vacuum distillation of a crude oil or of an effluent originating from a thermal conversion, hydrotreating, hydrocracking or hydroconversion unit, an aromatic cut extracted from a unit for the production of lubricants, a deasphalted oil resulting from a deasphalting unit, an asphalt resulting from a deasphalting unit, a residual fraction resulting from direct coal liquefaction, a vacuum distillate resulting from direct coal liquefaction, bituminous sands or their derivatives, oil shales or their derivatives, source rock oils or their derivatives, taken alone or as a mixture.

[0036] According to one or more implementations of the invention, the heavy fraction of hydrocarbons is a vacuum residue and / or an atmospheric residue.

[0037] According to one or more implementations of the invention, the hydrodemetallization catalyst of stage a) comprises from 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO, with respect to the total weight of the catalyst and from 1% to 30% by weight of molybdenum, expressed as molybdenum oxide MoO3, with respect to the total weight of the catalyst, on a mineral support chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals.

[0038] According to one or more implementations of the invention, the hydrotreating catalyst of stage b) comprises from 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO, with respect to the total weight of the catalyst and from 1% to 30% by weight of molybdenum, expressed as molybdenum oxide MoO3, with respect to the total weight of the catalyst, on a mineral support chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals.

[0039] According to one or more implementations of the invention, said separation section in stage c) comprises means for scrubbing by contact with an aqueous solution.

[0040] According to one or more implementations of the invention, the separation section c) comprises:

[0041] c1) a first separation stage carried out at a temperature greater than the precipitation temperature of ammonium halides, in order to obtain at least one first gas fraction and one liquid effluent,

[0042] c2) a second separation stage, fed by first gas fraction and at least a part of the liquid effluent resulting from stage c1) and an aqueous solution, said stage being carried out at a temperature lower than the precipitation temperature of ammonium halides, in order to obtain at least one second gas fraction, one aqueous effluent and one liquid product.

[0043] According to one or more implementations of the invention, the process according to the invention additionally comprises a stage d) of subsequent treatment of the at least one liquid product resulting from stage c), said stage d) comprising at least one stage chosen from the list consisting of hydrotreating, steam cracking, fluidized bed catalytic cracking, hydrocracking, deasphalting and the extraction of lubricating oils.

[0044] According to one or more implementations of the invention, in stage a), the fraction of pyrolysis oil and the heavy fraction of hydrocarbons of the feedstock are premixed before they are introduced into one of said permutable reactors.

[0045] According to one or more implementations of the invention, in stage a), the fraction of pyrolysis oil of the feedstock is introduced separately from the heavy fraction of hydrocarbons into one of said permutable reactors.

[0046] According to one or more implementations of the invention, stage a) comprises a stage of preheating said heavy fraction of hydrocarbons, preferably at a temperature of between 280° C. and 450° C., and a stage of preheating the fraction of pyrolysis oil carried out at a lower temperature than that of said heavy fraction of hydrocarbons, before the introduction of the feedstock into one of said permutable reactors.

[0047] The invention also relates to the product liable to be obtained, and preferably obtained, by the process according to the invention.

[0048] Such a product advantageously comprises a content of silicon of less than or equal to 10 ppm by weight and / or a content of chlorine element of less than or equal to 10 ppm by weight, with respect to the weight of the product.DESCRIPTION OF THE EMBODIMENTS

[0049] A few definitions are given below for a better understanding of the invention.

[0050] In the present description, the term “to comprise” is synonymous with (means the same thing as) “to include” and “to contain”, and is inclusive or open-ended and does not exclude other elements which are not mentioned. It is understood that the term “to comprise” includes the exclusive and closed term “to consist”.

[0051] In the present description, the expression “of between . . . and . . . ” means that the limiting values of the interval are included in the described range of values, unless otherwise specified.

[0052] Within the meaning of the present invention, the various parameter ranges for a given stage, such as the pressure ranges and the temperature ranges, can be used alone or in combination. For example, within the meaning of the present invention, a range of preferred pressure values can be combined with a range of more preferred temperature values.

[0053] In the present description, specific and / or preferred embodiments of the invention may be described. They can be employed separately or combined together, without limitation of combination when this is technically feasible.

[0054] Subsequently, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor-in-chief D.R. Lide, 81st edition, 2000-2001). For example, group VIII (or VIIIB) according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification.

[0055] The content of metals is measured by X-ray fluorescence.

[0056] The term “treatment process” refers to a process including hydroconversion and hydrotreating reactions.

[0057] The term “hydroconversion” refers to a process, the main aim of which is to reduce the boiling point range of a feedstock, and in which a substantial part of the feedstock is converted into products having lower boiling point ranges than those of the starting feedstock. Hydroconversion generally involves the fragmentation of larger hydrocarbon molecules to give smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen to carbon ratio. The reactions carried out during the hydroconversion make it possible to reduce the size of molecules of hydrocarbons, mainly by cleaving carbon-carbon bonds, in the presence of hydrogen in order to saturate the severed bonds and the aromatic rings. The mechanism by which the hydroconversion takes place typically involves the formation of free radicals of hydrocarbons during the fragmentation, mainly by thermal cracking, followed by the capping of the endings or fragments of free radicals with hydrogen in the presence of active catalyst sites. Of course, during a hydroconversion process, other reactions typically associated with hydrotreating can take place, such as, inter alia, the removal of sulfur or nitrogen from the feedstock, or the saturation of olefins, and as defined more broadly below.

[0058] The term “hydrotreating”, commonly referred to as “HDT”, refers to a gentler operation, the main aim of which is to remove impurities, such as sulfur, nitrogen, oxygen, halides and traces of metals, from the feedstock and to saturate olefins and / or to stabilize free radicals of hydrocarbons by reacting them with hydrogen rather than by leaving them to react with themselves. The main aim is not to change the boiling point range of the feedstock. Thus, the hydrotreating comprises in particular hydrodesulfurization (commonly known as “HDS”) reactions, hydrodenitrogenation (commonly known as “HDN”) reactions and hydrodemetallization (commonly known as “HDM”) reactions, accompanied by hydrogenation, hydrodeoxygenation (commonly known as “HDO”), hydrodearomatization, hydrodechlorination, hydroisomerization, hydrodealkylation, hydrocracking or hydrodeasphalting reactions and by the reduction of Conradson carbon.

[0059] In the continuation of the text, the term “pyrolysis oil” is understood to mean an oil resulting from the pyrolysis of plastics and / or of tyres and / or of SRFs, unless otherwise indicated. Also for the sake of simplicity, the term “heavy fraction of hydrocarbons” of the feedstock denotes a heavy fraction of hydrocarbons of fossil origin, unless otherwise indicated.The Feedstock

[0060] According to an essential aspect of the invention, the feedstock predominantly comprises a heavy fraction of hydrocarbons of fossil origin and a minor fraction of plastic and / or tyre and / or SRF pyrolysis oil.

[0061] According to a preferred embodiment of the invention, the feedstock is constituted of said minor fraction of plastic and / or tyre and / or SRF pyrolysis oil, and of a major fraction of heavy hydrocarbons of fossil origin.

[0062] The process according to the invention is thus specific to the hydroconversion of a mixture of plastic and / or tyre and / or SRF pyrolysis oil at low content and of a heavy fraction of hydrocarbons of fossil origin.

[0063] The fraction of plastic and / or tyre and / or SRF pyrolysis oil constitutes less than 50% by weight of the feedstock (total weight of the feedstock), preferably between 1% and 45% by weight of the feedstock, more preferentially between 2% and 30% by weight of the feedstock, more preferentially still between 2% and 25% by weight of the feedstock, more preferentially still between 3% and 20% by weight of the feedstock and in an even more preferred way between 5% and 20% by weight of the feedstock, indeed even between 5% and 15% by weight of the feedstock.

[0064] The feedstock can be constituted of these two fractions alone: the fraction of pyrolysis oil and the heavy fraction of hydrocarbons, the sum of the fraction of pyrolysis oil and of the heavy fraction of hydrocarbons forming 100% by weight of the feedstock. The heavy fraction of hydrocarbons can constitute, preferably when the feedstock is constituted of said heavy fraction of hydrocarbons and of the fraction of pyrolysis oil, between 55% and 99% by weight of the feedstock, preferably between 70% and 98% by weight of the feedstock, more preferentially between 75% and 98% by weight of the feedstock, more preferentially still between 80% and 97% by weight of the feedstock and in an even more preferred way between 80% and 95% by weight of the feedstock, indeed even between 85% and 95% by weight of the feedstock.

[0065] According to the invention, a “plastic pyrolysis oil or tyre pyrolysis oil or SRF pyrolysis oil” is an oil, advantageously in liquid form at ambient temperature, resulting from the pyrolysis of plastics, preferably of plastic waste originating in particular from collection and sorting channels, or resulting from the pyrolysis of spent tyres or also from the pyrolysis of SRFs. It comprises in particular a mixture of hydrocarbon compounds, especially paraffins, olefins (mono- and / or diolefins), naphthenes and aromatics. At least 80% by weight of these hydrocarbon compounds preferably have a boiling point of less than 700° C. and preferably of less than 550° C. In particular, depending on the origin of the pyrolysis oil, the latter can comprise up to 70% by weight of paraffins, up to 90% by weight of naphthenes, up to 90% by weight of olefins and up to 90% by weight of aromatics, it being understood that the sum of the paraffins, of the naphthenes, of the olefins and of the aromatics is equal to 100% by weight of the hydrocarbon compounds.

[0066] The pyrolysis oil can comprise diolefins. The content of diolefins is commonly determined indirectly as the maleic anhydride value (MAV). The method is based on the Diels-Alder addition reaction between the conjugated diolefins and the maleic anhydride. The method for the determination of the MAV is described in C. Lopez-Garcia et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil & Gas Science and Technology-Rev. IFP, Vol. 62 (2007), No. 1, pp. 57-68. The MAV is expressed in mg of maleic anhydride having reacted with 1 g of sample (mg / g). The MAV varies between 5 and 100 mg / g in the pyrolysis oils.

[0067] The density of the pyrolysis oil, measured at 15° C. according to the ASTM D4052 method, is generally of between 0.75 g / cm3 and 0.99 g / cm3, preferably of between 0.75 g / cm3 and 0.95 g / cm3.

[0068] The pyrolysis oil additionally can comprise, and usually comprises, impurities, such as metals, in particular iron, silicon or halogenated compounds, in particular chlorinated compounds. These impurities can be present in the pyrolysis oil at high contents, for example up to 500 ppm by weight or also 700 ppm by weight, indeed even 1000 ppm by weight, and even 5000 ppm by weight, of halogen elements (in particular chlorine but also bromine, fluorine, iodine or astatine) contributed by halogenated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or also between 1 and 500 ppm by weight of halogen elements. The pyrolysis oil can contain up to 500 ppm by weight or also 700 ppm by weight, indeed even 1000 ppm by weight and even 5000 ppm by weight of chlorine element contributed by chlorinated compounds, and generally between 1 and 1000 ppm by weight or between 1 and 700 ppm by weight or also between 1 and 500 ppm by weight of chlorine element.

[0069] The oil can comprise up to 200 ppm by weight, indeed even 1500 ppm by weight, of metal or semi-metal elements, and generally between 1 and 200 ppm by weight or between 1 and 1500 ppm by weight of metal or semi-metal elements. Alkali metals, alkaline earth metals, transition metals, post-transition metals and metalloids can be put into the same category as contaminants of metal nature, referred to as metals or metal or semi-metal elements. In particular, the metals or metal or semi-metal elements comprise silicon, iron or both of these elements. The pyrolysis oil can in particular comprise up to 200 ppm by weight or also 1000 ppm by weight of silicon, and generally between 1 and 200 ppm by weight or between 1 and 1000 ppm by weight or also between 1 and 500 ppm by weight of silicon. The pyrolysis oil can in particular comprise up to 50 ppm by weight or also 100 ppm by weight of iron, and generally between 1 and 50 ppm by weight or between 1 and 100 ppm by weight of iron. The pyrolysis oil can also comprise phosphorus, sodium, calcium, potassium and magnesium.

[0070] The pyrolysis oil can also comprise other impurities, such as heteroelements contributed in particular by sulfur compounds, oxygen compounds and / or nitrogen compounds, at contents generally of less than 40 000 ppm by weight of heteroelements and preferably of less than 15 500 ppm by weight of heteroelements, and generally between 1 and 40 000 ppm by weight or between 1 and 15 500 ppm by weight of heteroelements. The sulfur compounds are generally present in a content of less than 15 000 ppm by weight and preferably of less than 10 000 ppm by weight, and generally between 1 and 15 000 ppm by weight or between 1 and 10 000 ppm by weight of sulfur compounds.

[0071] The oxygen compounds are generally present in a content of less than 15 000 ppm by weight and preferably of less than 10 000 ppm by weight, and generally between 1 and 15 000 ppm by weight or between 1 and 10 000 ppm by weight of oxygen compounds.

[0072] The nitrogen compounds are generally present in a content of less than 10 000 ppm by weight and preferably of less than 5000 ppm by weight, and generally between 1 and 10 000 ppm by weight or between 1 and 5000 ppm by weight of nitrogen compounds.

[0073] The pyrolysis oil can also comprise other impurities, such as heavy metals, for example mercury, arsenic, zinc and lead, for example up to 100 ppb by weight or also 200 ppb by weight of mercury or of arsenic, and generally between 1 and 200 ppb by weight or between 1 and 100 ppb by weight of heavy metals.

[0074] The process according to the invention is particularly well suited to treating a pyrolysis oil laden with impurities, in combination with a heavy feedstock of hydrocarbons as is defined in more detail below. The term “laden with impurities” is understood to mean that the pyrolysis oil has the following properties:

[0075] a content of aromatics of between 0% and 90% by weight, often of between 20% and 90% by weight, and which can be of between 50% and 90% by weight, indeed even of between 30% and 70% by weight;

[0076] a content of chlorine of between 2 ppm by weight and 5000 ppm by weight, often of between 200 ppm by weight and 5000 ppm by weight, and which can be of between 500 ppm by weight and 5000 ppm by weight;

[0077] a content of metal elements of between 0 ppm by weight and 1500 ppm by weight, and which can be of between 1 ppm by weight and 1100 ppm by weight;

[0078] including a content of iron element of between 0 ppm by weight and 100 ppm by weight, often of between 5 ppm by weight and 100 ppm by weight, and which can be of between 10 ppm by weight and 100 ppm by weight;

[0079] and a content of silicon element of between 0 ppm by weight and 1000 ppm by weight, often of between 20 ppm by weight and 1000 ppm by weight, indeed even between 30 ppm by weight or 40 ppm by weight and 1000 ppm by weight, and which can also be of between 100 ppm by weight and 1000 ppm by weight.

[0080] The plastic and / or tyre and / or SRF pyrolysis oil can result from a thermal or catalytic pyrolysis treatment or also be prepared by hydropyrolysis (pyrolysis in the presence of a catalyst and of hydrogen).

[0081] The heavy fraction of hydrocarbons of fossil origin of the feedstock of the process according to the invention is a heavy fraction of hydrocarbons having an initial boiling point of at least 340° C. and a final boiling point of at least 550° C. and containing sulfur and nitrogen. Preferably, its initial boiling point is at least 350° C., preferentially at least 375° C., and its final boiling point is at least 550° C., preferentially at least 560° C. and more preferentially still at least 600° C.

[0082] The heavy fraction of hydrocarbons of the feedstock can comprise, or be constituted of, atmospheric residues and / or of vacuum residues resulting from the atmospheric and / or vacuum distillation of a crude oil.

[0083] The heavy fraction of hydrocarbons of the feedstock can also be constituted of atmospheric and / or vacuum residues resulting from the atmospheric and / or vacuum distillation of effluents originating from thermal conversion, hydrotreating, hydrocracking and / or hydroconversion units.

[0084] The heavy fraction of hydrocarbons of the feedstock can also be constituted of aromatic cuts extracted from a unit for the production of lubricants, of deasphalted oils resulting from a deasphalting unit (raffinates of the deasphalting unit) or of asphalts resulting from a deasphalting unit (residues of the deasphalting unit).

[0085] The heavy fraction of hydrocarbons of the feedstock can also be a residual fraction resulting from direct coal liquefaction (an atmospheric residue and / or a vacuum residue resulting, for example, from the H-Coal® process).

[0086] All these fractions of fossil origin can be used to constitute the heavy fraction of hydrocarbons of the feedstock treated according to the invention, alone or as a mixture.

[0087] According to one or more implementations, the heavy fraction of hydrocarbons comprises, or can be constituted of, at least one of the following feedstocks, alone or as a mixture: an atmospheric residue or a vacuum residue resulting from the atmospheric and / or vacuum distillation of a crude oil or of an effluent originating from a thermal conversion, hydrotreating, hydrocracking or hydroconversion unit, an aromatic cut extracted from a unit for the production of lubricants, a deasphalted oil resulting from a deasphalting unit, an asphalt resulting from a deasphalting unit or a residual fraction resulting from direct coal liquefaction.

[0088] In the present invention, the heavy fraction of hydrocarbons which is treated is preferably an atmospheric residue or a vacuum residue, or a mixture of these residues.

[0089] The heavy fraction of hydrocarbons of the feedstock treated according to the invention contains impurities, such as sulfur and nitrogen. It can also contain impurities, such as metals, Conradson carbon and asphaltenes, in particular C7 asphaltenes, which are insoluble in heptane.

[0090] The sulfur content can be greater than or equal to 0.1% by weight, indeed even greater than or equal to 0.5% or 1% by weight, and can be greater than or equal to 2% by weight.

[0091] The content of nitrogen is usually of between 1 ppm and 8000 ppm by weight, more generally between 200 ppm and 8000 ppm by weight, for example of between 2000 ppm and 8000 ppm by weight.

[0092] The contents of metals (in particular of Ni and of V) can be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight.

[0093] The content of Conradson carbon can be greater than or equal to 3% by weight, indeed even of at least 5% by weight. The content of Conradson carbon is defined by Standard ASTM D482 and represents, for a person skilled in the art, a well-known evaluation of the amount of carbon residues produced after a pyrolysis under standard temperature and pressure conditions.

[0094] The content of C7 asphaltenes (compounds insoluble in heptane according to Standard ASTM D6560, also corresponding to Standard NF T60-115) can amount to a minimum of 1% by weight and is often greater than or equal to 3% by weight (with the exception of a heavy fraction of hydrocarbons essentially comprising a deasphalted oil). C7 asphaltenes are compounds known for inhibiting the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly referred to as coke, and by their tendency to produce sediments which greatly limit the operability of the hydrotreating and hydroconversion units.

[0095] These contents of sulfur, nitrogen, metals, Conradson carbon and asphaltenes of the heavy fraction of hydrocarbons are expressed as % by weight of the total weight of the heavy fraction of hydrocarbons of the feedstock.

[0096] According to one or more implementations, the feedstock of the process according to the invention can additionally comprise, at a low content, typically between 1% and 20% by weight of the feedstock, indeed even between 1% and 10%, a vegetable and / or animal oil or fat, and / or a hydrocarbon fraction resulting from processes for the thermal and / or catalytic conversion of lignocellulosic biomass, such as an oil produced from lignocellulosic biomass, according to various liquefaction methods, such as hydrothermal liquefaction or pyrolysis, which is then co-treated with the plastic and / or tyre and / or SRF pyrolysis oil and the heavy fraction of hydrocarbons of fossil origin.

[0097] The oils / fats of vegetable and / or animal origin contain triglycerides and / or free fatty acids and / or esters. The vegetable oils can advantageously be crude or completely or partially refined, and can result from the following plants: rape, sunflower, soya, palm, palm kernel, olive, coconut, jatropha (French physic nut), castor oil plant, cotton, peanut, flax or sea kale, this list not being limiting. Algal oils or fish oils are also relevant. The oils / fats of vegetable and / or animal origin can be waste ones, for example waste cooking oils. The animal fats can be chosen from pig fat or fats composed of residues from the food industry or resulting from the catering industries.

[0098] The term “lignocellulosic biomass” denotes compounds derived from plants or from their by-products, and comprises constituents chosen from the group formed by cellulose, hemicellulose (carbohydrate polymers) and / or lignin (aromatic polymer).

[0099] According to one or more implementations, the feedstock of the process according to the invention does not comprise a vegetable and / or animal oil or fat fraction, or a hydrocarbon fraction resulting from processes for the thermal and / or catalytic conversion of lignocellulosic biomass, such as a biomass pyrolysis oil.(a0) Stage of Pretreatment of the Pyrolysis Oil (Optional)

[0100] The plastic and / or tyre and / or SRF pyrolysis oil can advantageously be pretreated in at least one optional pretreatment stage a0), prior to the hydrodemetallization stage a), in order to obtain a pretreated pyrolysis oil which feeds stage a).

[0101] According to an alternative form, this optional pretreatment stage a0) makes it possible to reduce the amount of contaminants and of solid particles, in particular the amount of iron and / or of silicon and / or of chlorine, possibly present in the pyrolysis oil. This optional stage a0) makes possible in particular the removal of sediments which can be formed as a result of the unstable nature of the pyrolysis oils and / or of a problem of compatibility between two different feedstocks. Thus, an optional stage a0) of pretreatment of the pyrolysis oil is advantageously carried out, especially when said oil comprises more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight, of metal elements and / or of solid particles, and especially when said oil comprises more than 5 ppm by weight of silicon, more particularly more than 10 ppm by weight, indeed even more than 20 ppm by weight, of silicon. Likewise, an optional stage a0) of pretreatment of the pyrolysis oil is advantageously carried out especially when said oil comprises more than 10 ppm by weight, in particular more than 20 ppm by weight, more particularly more than 50 ppm by weight, of chlorine.

[0102] Said optional pretreatment stage a0) can be carried out by any method known to a person skilled in the art which makes it possible to reduce the amount of contaminants. It can in particular comprise an adsorption stage and / or a filtration stage and / or a centrifugation stage and / or an electrostatic separation stage and / or a stage of scrubbing by means of an aqueous solution and / or a gas stripping stage.

[0103] The optional pretreatment stage a0) is advantageously carried out at a temperature between 2° and 400° C., preferably between 4° and 350° C., and at a pressure between 0.15 and 10.0 MPa abs., preferably between 0.2 and 7.0 MPa abs.

[0104] According to an alternative form, said optional pretreatment stage a0) is carried out in an adsorption section operated in the presence of at least one adsorbent. The adsorbent can be chosen from a zeolite, activated carbon, a clay, a silica or an alumina.

[0105] Advantageously, said adsorbent comprises less than 1% by weight of metal elements and is preferably devoid of metal elements. The term “metal elements of the adsorbent” should be understood as meaning the elements of columns 6 to 10 of the Periodic Table of the Elements (new IUPAC classification). The residence time of the feedstock in the adsorption section is generally of between 1 minute and 180 minutes.

[0106] Said adsorption section of the optional stage a0) comprises at least one adsorption column, preferably comprises at least two adsorption columns, preferentially between two and four adsorption columns, containing said adsorbent. When the adsorption section comprises two adsorption columns, one operating mode can be a “swing” operation, in which one of the columns is on-line, that is to say in operation, while the other column is in reserve. When the adsorbent of the on-line column is spent, this column is isolated, while the column in reserve is placed on-line, i.e. in operation. The spent adsorbent can subsequently be regenerated in situ and / or replaced with fresh adsorbent so that the column containing it can again be brought back on-line once the other column has been isolated.

[0107] Another operating mode is to have at least two columns operating in series. When the adsorbent of the column placed at the head is spent, this first column is isolated and the spent adsorbent is either regenerated in situ or replaced with fresh adsorbent. The column is subsequently brought back on-line in the last position, and so on. This operation is known as permutable mode, or according to the term PRS for Permutable Reactor System, or also “lead and lag”. The combination of at least two adsorption columns makes it possible to overcome the possible and potentially rapid poisoning and / or clogging of the adsorbent under the combined action of the metal contaminants, of the diolefins, of the gums resulting from the diolefins and of the insolubles possibly present in the pyrolysis oil to be treated. The reason for this is that the presence of at least two adsorption columns facilitates the replacement and / or the regeneration of the adsorbent, advantageously without shutdown of the pretreatment unit, indeed even of the process, thus making it possible to reduce the risks of clogging and thus to avoid shutdown of the unit because of clogging, to control the costs and to limit the consumption of adsorbent.

[0108] According to another alternative form, said optional pretreatment stage a0) is carried out in a section for scrubbing with an aqueous solution, for example water or an acidic or basic solution. This scrubbing section can comprise items of equipment which make it possible to bring the feedstock into contact with the aqueous solution and to separate the phases so as to obtain, on the one hand, the pretreated feedstock and, on the other hand, the aqueous solution comprising impurities. These items of equipment can include, for example, a stirred reactor, a decanter, a mixer-decanter and / or a cocurrentwise or countercurrentwise scrubbing column.

[0109] According to another alternative form, said optional pretreatment stage a0) is carried out by filtration. The filtration stage makes it possible to remove the inorganic solids, sediments and / or fines contained in the oil, in particular the metals, metal oxides and metal chlorides. Use is generally made of a filter, the size (for example the diameter or equivalent diameter) of the pores of which is less than 25 μm, preferably less than or equal to 10 μm, in an even more preferred way less than or equal to 5 μm. According to another alternative form, use may be made of a filter, the size of the pores of which is less than 25 μm but greater than 5 μm. Use may also be made of a series of filters with different pore sizes, in particular a series of filters having pore sizes decreasing in the direction of the circulation of the oil. These filtering media are well known for industrial uses. Cartridge filters or self-cleaning filters are suitable, for example. The solids content can be measured, for example, by the Heptane Insolubles test, ASTM D-3279 method. The content of insolubles in heptane has to be reduced to less than 0.5% by weight, preferably to less than 0.1%.

[0110] According to a specific embodiment, the stage of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, optionally followed by a filtration system, the size of the pores of which is less than 2 μm and preferably less than 1 μm.

[0111] According to another specific embodiment, the stage of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, followed by an electrostatic precipitation system.

[0112] According to another specific embodiment, the stage of pretreatment a0) by filtration comprises at least one filter, the size of the pores of which is less than 10 μm and preferably greater than 5 μm, followed by a system of filter(s) using filtration adjuvants, such as sand or diatomaceous earths.

[0113] According to another alternative form, said optional pretreatment stage a0) is carried out by centrifugation. According to another alternative form, the pretreatment stage a0) comprises a centrifugation and a filtration.

[0114] According to another alternative form, said optional pretreatment stage a0) is carried out by gas stripping, thus reducing the content of oxygen in the oil. The gas extraction can remove the oxygen (O2) which may be dissolved in the feedstock, thus reducing the probability of formation of free radicals resulting in polymerization in the downstream stages. The process generally involves bringing the oil into contact with an extraction gas (for example H2, N2 or a mixture of these), thus transferring at least a part of the dissolved oxygen of the oil to the extraction gas, followed by the separation of the extraction gas from the oil. The volume of extraction gas with respect to the volume of oil (the two volumes measured under gas extraction conditions) is generally greater than 1 and preferably at least 3. In specific embodiments, the extraction gas can contain at least 60% (molar percentage) of H2. Any dissolved H2 remaining in the feedstock after the gas extraction stage is not a problem, due to the downstream hydrodemetallization / hydrotreating. Preferably, the gas extraction stage is finished before any (pre) heating of the feedstock, in order to minimize the potential fouling.

[0115] Said optional pretreatment stage a0) generally comprises one or more, preferably several, treatments described above. It can in particular comprise a series of a stage of scrubbing using an aqueous solution and / or an adsorption stage, followed by a gas stripping stage, followed by a filtration stage and / or by a centrifugation stage. All these stages are preferably carried out before any (pre) heating of the feedstock.

[0116] Said optional pretreatment stage a0) thus makes it possible to obtain a pretreated pyrolysis oil which subsequently feeds the hydrodemetallization stage a).(a) Stage of Hydrodemetallization in Permutable Reactors

[0117] According to the invention, the process comprises a stage a) of hydrodemetallization carried out in a fixed bed reaction section comprising at least two permutable reactors, said section being fed at least by said feedstock, comprising predominantly said heavy fraction of hydrocarbons of fossil origin and a minor fraction of pyrolysis oil, optionally pretreated in stage a0), and a gas stream comprising hydrogen, in the presence of at least one hydrodemetallization catalyst, at a temperature between 30° and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1.

[0118] The fraction of pyrolysis oil and the heavy fraction of hydrocarbons can be produced in different ways into the hydrodemetallization stage.

[0119] According to a first alternative form, the fraction of pyrolysis oil can be premixed with the heavy fraction of hydrocarbons of the feedstock before entry into the reaction section of the hydrodemetallization stage a).

[0120] Another alternative form is the separate injection of the fraction of pyrolysis oil and of the heavy fraction of hydrocarbons into the reaction section of stage a). This injection mode may be preferred in order to prevent any problem related to a chemical incompatibility between the two fractions (risk of phase separation or of precipitation of asphaltenes, for example), or also in order to prevent a possible accelerated fouling of the preheating oven (the high contents of diolefins and olefins of the plastic and / or tyre and / or SRF pyrolysis oil can result in the formation of gums).

[0121] According to these two alternative embodiments, i.e. mixing or non-mixing of the fractions before they are introduced into the reaction section of the hydrodemetallization stage a), the feedstock, and in particular the heavy fraction of hydrocarbons of the feedstock, is generally preheated to a temperature suitable for the hydrodemetallization.

[0122] The preheating of the heavy fraction of hydrocarbons is preferably carried out at a temperature of between 280° C. and 450° C., more preferably still of between 300° C. and 400° C. and more preferably still of between 320° C. and 365° C.

[0123] This preheating can also comprise the heating of the fraction of pyrolysis oil, in particular if said fraction is injected separately from the heavy fraction of hydrocarbons, however preferably at a lower temperature than for the heavy fraction of hydrocarbons, so as to limit the formation of gums and / or the coking of the items of preheating equipment (for example ovens and heat exchangers) as a result of the presence of olefins and of diolefins in the fraction of pyrolysis oil. Advantageously, the fraction of pyrolysis oil can be preheated at a temperature of between ambient temperature, e.g. 15° C., and 350° C., preferably between 100° C. and 350° C., more preferentially between 100° C. and 250° C., more preferentially still between 100° C. and less than 230° C., indeed even between 100° C. and less than 200° C. The fraction of pyrolysis oil can, for example, be preheated by an oven or by mixing with a hotter gas stream comprising hydrogen originating from the hydrogen make-up and / or recycled from stage c) of the process according to the invention.

[0124] In the case of a mixture of the two fractions, the preheating can be carried out after, before or during the mixing. In this case, the preheating of the mixture of the two fractions is preferably carried out at a temperature of between 280° C. and 450° C., more preferably still of between 300° C. and 400° C. and more preferably still of between 320° C. and 365° C.

[0125] According to another embodiment where the heavy fraction of hydrocarbons and the fraction of pyrolysis oil are mixed, the fraction of pyrolysis oil is heated indirectly by the mixing with the heavy fraction of hydrocarbons (i.e., heat exchange between the two fractions by bringing said two fractions, which are at different temperatures, into contact).

[0126] Any means known to a person skilled in the art capable of preheating said feedstock can be used. There can be used at least one oven, commonly known as preheating oven, comprising, for example, at least one heating compartment, and / or tubes in which the feedstock flows, a mixer of the feedstock with H2, heat exchangers of any appropriate type, for example tubular or spiral heat exchangers in which the feedstock flows, and the like.

[0127] Before it is introduced into the reaction section of the hydrodemetallization stage a), the feedstock is subjected to a pressurization stage in order to be suited to the pressure operated in the reaction section of the hydrodemetallization stage a), for example using an appropriate pump. This pressurization stage is preferably carried out before the preheating stage.

[0128] The objective of this hydrodemetallization stage a) is to reduce the content of impurities, in particular of metals, especially of silicon, and of halogens (in particular of chlorine), and the content of diolefins and olefins, which can result from the fossil heavy fraction or from the pyrolysis oil, and thus to protect the downstream hydrotreating stage b) from deactivation and clogging, hence the notion of guard reactors.

[0129] These hydrodemetallization guard reactors are employed as permutable reactors (PRS, for Permutable Reactor System, technology), as described in Patent FR 2 681 871.

[0130] The term “permutable reactors” is understood to mean an assembly of at least two reactors, one of the reactors of which can be shut down, generally for regeneration or replacement of the catalyst or for maintenance, while the other (or the others) is (are) in operation.

[0131] These permutable reactors are fixed beds located upstream of the fixed bed hydrotreating section of stage b) and equipped with lines and valves so as to be switched around among themselves, that is to say, for a system having two permutable reactors Ra and Rb, Ra can be upstream of Rb and vice versa. Each reactor Ra and Rb can be placed off-line so as to change the catalyst without shutting down the remainder of the unit. This change of catalyst (rinsing, discharging, recharging, sulfiding) is generally made possible by a conditioning section (set of items of equipment outside the main high-pressure loop). The reactor containing the fresh catalyst is subsequently brought back on-line in the last position, and so on. Permutation for change of catalyst occurs when the catalyst is no longer sufficiently active (poisoning by the metals and coking) and / or when the clogging results in an excessively high pressure drop.

[0132] According to an alternative form, there may be more than 2 permutable reactors in the section for hydrodemetallization in permutable reactors.

[0133] During the hydrodemetallization stage a), hydrodemetallization (commonly known as HDM) reactions occur but also hydrodesulfurization (commonly known as HDS) reactions, hydrodenitrogenation (commonly known as HDN) reactions accompanied by hydrogenation, hydrodechlorination, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking or hydrodeasphalting reactions and by the reduction of Conradson carbon. Stage a) is referred to as the hydrodemetallization stage owing to the fact that it removes the majority of the metals from the feedstock.

[0134] Furthermore, the silicon contained in the feedstock is deposited on the catalyst(s) during this stage. It is the same for the chlorinated compounds, a minor part (the mineral part) of which is deposited on the catalyst, whereas the organic chlorinated compounds are converted into HCl.

[0135] The hydrodemetallization stage a) in permutable reactors according to the invention can advantageously be carried out at a temperature of between 300° C. and 500° C., preferably between 350° C. and 430° C., and under an absolute pressure of between 5 MPa and 35 MPa, preferably between 11 MPa and 26 MPa, in a preferred way between 14 MPa and 20 MPa. The temperature is usually adjusted according to the desired level of hydrodemetallization and the targeted duration of the treatment. The temperature is generally adjusted in order to remove most and preferably all of the metals, including silicon. Most often, the space velocity of the hydrocarbon feedstock, also known as liquid hourly space velocity (LHSV) or hourly space velocity (HSV), commonly known as HSV, and which is defined as being the flow rate by volume of the feedstock divided by the total volume of the catalyst, can be within a range extending from 0.1 h−1 to 5 h−1, preferably from 0.15 h−1 to 3 h−1 and more preferably from 0.2 h−1 to 2 h−1.

[0136] The amount of hydrogen mixed with the feedstock can be of between 100 and 5000 standard cubic metres (Sm3) per cubic metre (m3) of liquid feedstock, preferentially between 200 Sm3 / m3 and 2000 Sm3 / m3 and more preferentially between 300 Sm3 / m3 and 1000 Sm3 / m3.

[0137] Stage a) of hydrodemetallization in permutable reactors is carried out industrially in at least two fixed bed reactors and preferentially with a downwards liquid stream. Each permutable reactor is a fixed bed reactor having n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrodemetallization catalyst.

[0138] According to one implementation of the invention, at least one reactor of the hydrodemetallization stage a) or of the hydrotreating stage b), and preferably all the reactors, is (are) equipped with a filtration and dispensing device, for example a device such as those described in Patent Applications FR 3 043 339 and FR 3 051 375.

[0139] According to one implementation of the invention, stage a) and / or stage b) can employ, upstream of the hydrodemetallization or hydrotreating catalyst(s), at least one guard bed containing adsorbents of alumina, silica, silica-alumina, zeolite and / or activated carbon type optionally containing metals from group VIB and / or VIII. Use may also be made of a series of guard beds with particles of different diameters, in particular a series of guard beds having decreasing diameters in the direction of the circulation of the feedstock (also referred to as “grading”).

[0140] The hydrodemetallization catalysts used are preferably known catalysts. They can be granular catalysts comprising, on a support, at least one metal or metal compound having a hydro-dehydrogenating function. These catalysts can advantageously be catalysts comprising at least one metal from group VIII, chosen generally from the group consisting of nickel and cobalt, and / or at least one metal from group VIB, preferably molybdenum and / or tungsten. It is possible to employ, for example, a catalyst comprising from 0.5% to 10% by weight of nickel, preferably from 1% to 5% by weight of nickel (expressed as nickel oxide NiO), and from 1% to 30% by weight of molybdenum, preferably from 3% to 20% by weight of molybdenum (expressed as molybdenum oxide MoO3), with respect to the weight of the catalyst, on a mineral support. The total content of oxides of metals from groups VIB and Vill can be from 5% to 40% by weight, preferably from 5% to 30% by weight, with respect to the weight of the catalyst, and the ratio by weight, expressed as metal oxide, of metal (or metals) from group VIB to metal (or metals) from group VIII is generally between 20 and 1 and most often between 10 and 2.

[0141] The support can, for example, be chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals. Advantageously, this support can include other doping compounds, in particular oxides chosen from the group consisting of boron oxide, zirconia, ceria, titanium oxide, phosphoric anhydride and a mixture of these oxides. Use is most often made of an alumina support and very often of an alumina support doped with phosphorus and optionally boron. When phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight, with respect to the weight of the alumina, and advantageously at least 0.001% by weight, with respect to the total weight of the alumina. When boron trioxide B2O5 is present, its concentration is less than 10% by weight, with respect to the weight of the alumina, and advantageously at least 0.001%, with respect to the total weight of the alumina. The alumina used can be a γ (gamma) or η (eta) alumina. Said hydrodemetallization catalyst is, for example, in the form of extrudates.

[0142] Catalysts which can be used in stage a) of hydrodemetallization in permutable reactors are, for example, shown in the documents of Patents EP 0 113 297, EP 0 113 284, U.S. Pat. Nos. 5,221,656, 5,827,421, 7,119,045, 5,622,616 and 5,089,463.

[0143] Said hydrodemetallization stage a) makes it possible to obtain a hydrodemetallized effluent, that is to say an effluent having a reduced content of metals, including of silicon, of chlorine and having a reduced content of olefins, in particular of diolefins. Preferably, at least 50% and more preferentially at least 75% of the chlorine, of the silicon, of the metals and of the diolefins of the initial feedstock are respectively removed during stage a).

[0144] At the end of the hydrodemetallization stage a), the content of metals Ni and V is generally less than 20 ppm by weight and preferably less than 10 ppm by weight, with respect to the weight of the effluent.

[0145] At the end of the hydrodemetallization stage a), the content of silicon is generally less than 10 ppm by weight and preferably less than 5 ppm by weight, in a preferred way less than or equal to 2 ppm by weight, indeed even less than or equal to 1 ppm by weight, with respect to the weight of the effluent.

[0146] At the end of the hydrodemetallization stage a), the content of chlorine is generally less than 10 ppm by weight and preferably less than 5 ppm by weight, in a preferred way less than or equal to 2 ppm by weight, indeed even less than or equal to 1 ppm by weight, with respect to the weight of the effluent.

[0147] At the end of the hydrodemetallization stage a), the content of diolefins, expressed as MAV value as defined above, is generally less than 5 mg / g, preferably less than 1 mg / g.

[0148] The effluent obtained on conclusion of the hydrodemetallization stage a) is sent, preferably directly, to the hydrotreating stage b).(b) Hydrotreating Stage

[0149] According to the invention, the treatment process comprises a hydrotreating stage b) carried out in a reaction section comprising at least one fixed bed reactor, said section being fed at least by said effluent resulting from stage a) and optionally a gas stream comprising hydrogen, in the presence of at least one hydrotreating catalyst, at a temperature between 30° and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1.

[0150] The hydrotreating stage b) includes hydrotreating reactions but also hydroconversion reactions as defined above in the “definition” section.

[0151] In the hydrotreating stage b), the degree of conversion is moderate, indeed even low, generally less than 45%, most often less than 35%, at the cycle end, and less than 25% at the cycle start. The degree of conversion generally varies during the cycle as a result of the increase in temperature in order to compensate for the catalytic deactivation. The degree of conversion is defined as being the fraction by weight of organic compounds having a boiling point of greater than 520° C. in the feedstock at the inlet of the reaction section minus the fraction by weight of organic compounds having a boiling point of greater than 520° C. in the effluent at the outlet of the reaction section, the whole divided by the fraction by weight of organic compounds having a boiling point of greater than 520° C. in the feedstock at the inlet of the reaction section.

[0152] According to a preferred alternative form, the hydrotreating stage b) comprises a first hydrodemetallization (HDM) stage b1) carried out in one or more hydrodemetallization zones in fixed beds and a subsequent second hydrodesulfurization (HDS) stage b2) carried out in one or more hydrodesulfurization zones in fixed beds. During said first hydrodemetallization stage b1), the effluent from stage a) is brought into contact with a hydrodemetallization catalyst, under hydrodemetallization conditions, and then, during said second hydrodesulfurization stage b2), the effluent from the first hydrodemetallization stage b1) is brought into contact with a hydrodesulfurization catalyst, under hydrodesulfurization conditions. This process, known under the name of Hyvahl-F™, is, for example, described in U.S. Pat. No. 5,417,846.

[0153] A person skilled in the art easily understands that, in the hydrodemetallization stage b1), hydrodemetallization reactions are carried out but, at the same time, a portion of the other hydrotreating reactions, and in particular hydrodesulfurization and hydrocracking reactions, is also carried out. Likewise, in the hydrodesulfurization stage b2), hydrodesulfurization reactions are carried out but, at the same time, a portion of the other hydrotreating reactions, and in particular hydrodemetallization and hydrocracking reactions, is also carried out.

[0154] A person skilled in the art sometimes defines a transition zone in which all the types of hydrotreating reaction take place. According to another alternative form, the hydrotreating stage b) comprises a first hydrodemetallization stage b1) carried out in one or more hydrodemetallization zones in fixed beds, a subsequent second transition stage b2) carried out in one or more transition zones in fixed beds and a subsequent third hydrodesulfurization stage b3) carried out in one or more hydrodesulfurization zones in fixed beds. During said first hydrodemetallization stage b1), the effluent from stage a) is brought into contact with a hydrodemetallization catalyst, under hydrodemetallization conditions, then, during said second transition stage b2), the effluent from the first hydrodemetallization stage b1) is brought into contact with a transition catalyst, under transition conditions, and then, during said third hydrodesulfurization stage b3), the effluent from the second transition stage b2) is brought into contact with a hydrodesulfurization catalyst, under hydrodesulfurization conditions.

[0155] The need for a hydrodemetallization stage b1) according to the above alternative forms, in addition to the hydrodemetallization stage a) in permutable guard reactors, is justified when the hydrodemetallization carried out during stage a) is not sufficient to protect the catalysts of stage b), in particular the hydrodesulfurization catalysts.

[0156] Each fixed bed reactor comprises n catalytic beds, n being an integer greater than or equal to 1, each comprising at least one hydrotreating catalyst.

[0157] The hydrotreating stage b) according to the invention is carried out under hydrotreating conditions. It can advantageously be carried out at a temperature of between 300° C. and 500° C., preferably between 350° C. and 430° C., and under an absolute pressure of between 5 MPa and 35 MPa, preferably between 11 MPa and 26 MPa, in a preferred way between 14 MPa and 20 MPa. The temperature is usually adjusted according to the desired level of hydrotreating and the targeted duration of the treatment. Most often, the space velocity of the feedstock, also known as liquid hourly space velocity (LHSV) or hourly space velocity (HSV), commonly known as HSV, and which is defined as being the flow rate by volume of the feedstock divided by the total volume of the catalyst, can be within a range extending from 0.1 h−1 to 5 h−1, preferably from 0.1 h−1 to 2 h−1 and more preferably from 0.1 h−1 to 1 h−1. The amount of hydrogen mixed with the feedstock can be of between 100 and 5000 standard cubic metres (Sm3) per cubic metre (m3) of liquid feedstock, preferentially between 200 Sm3 / m3 and 2000 Sm3 / m3 and more preferentially between 300 Sm3 / m3 and 1500 Sm3 / m3. The hydrotreating stage b) can be carried out industrially in one or more reactors having a downwards liquid stream.

[0158] The hydrotreating catalysts used are preferably known catalysts. They can be granular catalysts comprising, on a support, at least one metal or metal compound having a hydro-dehydrogenating function. These catalysts can advantageously be catalysts comprising at least one metal from group VIII, chosen generally from the group consisting of nickel and cobalt, and / or at least one metal from group VIB, preferably molybdenum and / or tungsten. It is possible to employ, for example, a catalyst comprising from 0.5% to 10% by weight of nickel, preferably from 1% to 5% by weight of nickel (expressed as nickel oxide NiO), and from 1% to 30% by weight of molybdenum, preferably from 3% to 20% by weight of molybdenum (expressed as molybdenum oxide MoO3), with respect to the weight of the catalyst, on a mineral support. This support can, for example, be chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals.

[0159] Advantageously, this support can include other doping compounds, in particular oxides chosen from the group consisting of boron oxide, zirconia, ceria, titanium oxide, phosphoric anhydride and a mixture of these oxides. Use is most often made of an alumina support and very often of an alumina support doped with phosphorus and optionally boron. When phosphorus pentoxide P2O5 is present, its concentration is less than 10% by weight, with respect to the weight of the alumina, and advantageously at least 0.001% by weight, with respect to the total weight of the alumina. When boron trioxide B2O5 is present, its concentration is less than 10% by weight, with respect to the weight of the alumina, and advantageously at least 0.001%, with respect to the total weight of the alumina. The alumina used can be a γ (gamma) or η (eta) alumina. This catalyst is most often in the form of extrudates. The total content of oxides of metals from groups VIB and VIII can be from 3% to 40% by weight and in general from 5% to 30% by weight, with respect to the weight of the catalyst, and the ratio by weight, expressed as metal oxide, of metal (or metals) from group VIB to metal (or metals) from group VIII is generally between 20 and 1 and most often between 10 and 2.

[0160] In the case of a hydrotreating stage including a hydrodemetallization (HDM) stage b1) and then a hydrodesulfurization (HDS) stage b2), use is preferably made of specific catalysts suited to each stage. Catalysts which can be used in the hydrodemetallization stage b1) are, for example, shown in the documents of Patents EP 0 113 297, EP 0 113 284, U.S. Pat. Nos. 5,221,656, 5,827,421, 7,119,045, 5,622,616 and 5,089,463. Catalysts which can be used in the hydrodesulfurization stage b3) are, for example, shown in the documents of Patents EP 0 113 297, EP 0 113 284, U.S. Pat. Nos. 6,589,908, 4,818,743 and 6,332,976. Use may also be made of a mixed catalyst, also known as transition catalyst, which is active in hydrodemetallization and in hydrodesulfurization, both for the hydrodemetallization section b1) and for the hydrodesulfurization section b2), as described in the document of Patent FR 2 940 143.

[0161] In the case of a hydrotreating stage including a hydrodemetallization (HDM) stage b1), then a transition stage b2) and then a hydrodesulfurization (HDS) stage b3), use is preferably made of specific catalysts suited to each stage. Catalysts which can be used in the hydrodemetallization stage b1) are, for example, shown in the documents of Patents EP 0 113 297, EP 0 113 284, U.S. Pat. Nos. 5,221,656, 5,827,421, 7,119,045, 5,622,616 and 5,089,463. Catalysts which can be used in the transition stage b2), which are active in hydrodemetallization and in hydrodesulfurization, are, for example, described in the document of Patent FR 2 940 143. Catalysts which can be used in the hydrodesulfurization stage b3) are, for example, shown in the documents of Patents EP 0 113 297, EP 0 113 284, U.S. Pat. Nos. 6,589,908, 4,818,743 and 6,332,976. Use may also be made of a transition catalyst as described in the document of Patent FR 2 940 143 for the sections b1), b2) and b3). The hydrotreating stage b) is carried out under conditions which make it possible to obtain a hydrotreated effluent, that is to say having a reduced content of sulfur, nitrogen, asphaltenes and Conradson carbon.

[0162] At the end of the hydrotreating stage b), the content of sulfur is generally less than 0.5% (5000 ppm) by weight and preferably less than 0.48% (4800 ppm) by weight, with respect to the weight of the effluent.

[0163] At the end of the hydrotreating stage b), the content of nitrogen is generally less than 3500 ppm by weight and preferably less than 3000 ppm by weight, with respect to the weight of the effluent.

[0164] At the end of the hydrotreating stage b), the content of C7 asphaltenes is generally less than 2% by weight and preferably less than 1% by weight, with respect to the weight of the effluent.

[0165] At the end of the hydrotreating stage b), the content of Conradson carbon is generally less than 8% by weight and preferably less than 6% by weight, with respect to the weight of the effluent.

[0166] Said effluent resulting from the hydrotreating stage b) contains the conversion products; in particular, said effluent has a reduced content (with respect to the feedstock) of hydrocarbons having an initial boiling point of at least 340° C., or of at least 350° C., 375° C., 450° C., 460° C., 500° C., or also 600° C., according to the nature of the feedstock.(c) Separation Stage

[0167] According to the invention, the process additionally comprises a separation stage c), which separates a part, or all, of the effluent resulting from stage b) in a separation section resulting in a gaseous effluent and at least one liquid product.

[0168] This separation stage c) separates a part or all of said effluent into several fractions, including at least one liquid product which can be a light cut (naphtha, diesel, kerosene), intermediate cut (vacuum distillate) or heavy cut (vacuum residue).

[0169] The separation stage c) is carried out in a separation section which comprises any separation means known to a person skilled in the art. Said separation section can comprise one or more flash drums arranged in series, and / or one or more steam stripping and / or hydrogen stripping columns, and / or an atmospheric distillation column, and / or a vacuum distillation column.

[0170] According to one or more embodiments, this separation stage c) is carried out by a series of at least two successive flash drums.

[0171] According to one or more other embodiments, this separation stage c) is carried out by one or more steam stripping and / or hydrogen stripping columns.

[0172] According to one or more preferred embodiments, this separation stage c) is carried out by an atmospheric distillation column, and more preferentially by an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

[0173] According to the most preferred embodiment(s), this separation stage c) is carried out by one or more flash drums, an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

[0174] The gaseous effluent comprises in particular H2, H2S, NH3 and C1-C4 hydrocarbons. This gaseous effluent can be separated from the effluent obtained on conclusion of stage b) using separation devices well known to a person skilled in the art, in particular using one or more knockout drums which can operate at different pressures and temperatures, optionally in combination with a steam or hydrogen stripping means and with one or more distillation columns. The effluent obtained on conclusion of the hydrotreating stage b) is advantageously separated in at least one knockout drum into at least one gaseous effluent and at least one liquid product. These separators can, for example, be high-pressure high-temperature (HPHT) separators and / or high-pressure low-temperature (HPLT) separators.

[0175] After an optional cooling, this gaseous effluent is preferably treated in a hydrogen purification means, so as to recover the hydrogen not consumed during the hydrodemetallization and hydrotreating reactions. The hydrogen purification means can be a scrubbing with amines, a membrane, a system of PSA type or several of these means arranged in series. The purified hydrogen can then advantageously be recycled in the process according to the invention, after an optional recompression. The hydrogen can be introduced at the inlet of the hydrodemetallization stage a) and / or at various places during the hydrotreating stage b). The hydrogen (hot because exiting from stage c)) can also be used to preheat the fraction of pyrolysis oil when it is introduced separately from the heavy fraction. The gaseous hydrogen recovered can also be used in other installations of the refinery.

[0176] The separation stage c) can also comprise an atmospheric distillation and / or a vacuum distillation. Advantageously, the separation stage c) additionally comprises at least one atmospheric distillation, in which the liquid effluent obtained after gas / liquid separation is fractionated by atmospheric distillation to give at least one atmospheric distillate fraction and at least one atmospheric residue fraction.

[0177] In addition, the separation stage c) of the process according to the invention can advantageously additionally comprise at least one vacuum distillation in which the liquid effluent obtained after gas / liquid separation and / or the atmospheric residue fraction obtained after atmospheric distillation is (are) fractionated by vacuum distillation to give at least one vacuum distillate fraction and at least one vacuum residue fraction. Preferably, the separation stage c) comprises, first of all, an atmospheric distillation, in which the liquid effluent obtained after gas / liquid separation is fractionated by atmospheric distillation to give at least one atmospheric distillate fraction and at least one atmospheric residue fraction, then a vacuum distillation in which the atmospheric residue fraction obtained after atmospheric distillation is fractionated by vacuum distillation to give at least one vacuum distillate fraction and at least one vacuum residue fraction. The vacuum distillate fraction typically contains fractions of vacuum gas oil type.

[0178] Advantageously, the separation section can also comprise means for scrubbing at least one separated cut by contact with an aqueous solution.

[0179] This scrubbing makes it possible in particular to remove ammonium chloride salts originating essentially from the fraction of pyrolysis oil. These salts are formed by reaction between chloride ions, released by the hydrogenation of chlorinated compounds in HCl form during stages a) and b), then dissolution in water, and ammonium ions, generated by the hydrogenation of nitrogenous compounds in NH3 form during stages a) and b) and / or contributed by injection of an amine, then dissolution in water. The scrubbing thus makes it possible to limit the risks of blockage, in particular in transfer lines and / or in sections of the process of the invention, due to the precipitation of ammonium chloride salts. It also makes it possible to remove the hydrochloric acid formed by the reaction of hydrogen ions and chloride ions and thus to limit corrosion in the downstream items of equipment.

[0180] According to a preferred embodiment, the separation stage c) comprises:

[0181] c1) a first separation stage carried out at a temperature greater than the precipitation temperature of ammonium halides, in order to obtain at least one first gas fraction and one liquid effluent,

[0182] c2) a second separation stage, fed by first gas faction and at least a part of the liquid effluent resulting from stage c1) and an aqueous solution, said stage being carried out at a temperature lower than the precipitation temperature of ammonium halides, in order to obtain at least one second gas fraction, one aqueous effluent and one liquid product.

[0183] The objective of this separation by the combination of the hot separation stage c1) followed by the cold separation / scrubbing stage c2) is to remove chlorine in the form of ammonium chloride salts.

[0184] Chloride ions, released by the hydrogenation of chlorinated compounds in the HCl form during stages a) and b) (hydrodechlorination), and ammonia, generated by the hydrogenation of nitrogenous compounds in the NH3 form during stage b) in particular (hydrodenitrogenation), largely leave in the gaseous effluent by virtue of the hot separation of stage c1). This is because the high temperature of this separation stage c1) prevents the precipitation of ammonium chloride salts which are formed by reaction between chloride ions and ammonium ions. The separation at a lower temperature in stage c2) of the gaseous effluent and of a part of the liquid effluent brings about the precipitation of these ammonium chloride salts. The scrubbing with an aqueous solution (generally water) or with a basic aqueous solution (solution of sodium hydroxide, of amine(s), for example) of this stage c2) makes it possible to dissolve these salts in the aqueous effluent. A hydrocarbon effluent freed from chlorine is thus obtained.

[0185] The term “precipitation temperature” of the ammonium halides is understood to mean the temperature (under given conditions, such as the concentration and the pressure) at which the gaseous ammonia and the hydrogen halides precipitate, either by reacting to form solid crystals of ammonium halides or by dissolving in water. The precipitation temperature depends on the concentrations of halides and on the pressure according to thermodynamic principles.

[0186] The precipitation temperature of ammonium halides generally lies between 150 and 300° C. under the conditions of use of the present process.

[0187] The items of separation equipment or the separation drums can comprise, at the bottom, a zone making possible the separate settling of a hydrocarbon fraction and of an aqueous fraction comprising chloride salts, or also comprise a column for scrubbing the gases by bringing into contact with water or a basic solution.(d) Subsequent Treatment Stage(s) (Optional)

[0188] One or more stages of subsequent treatment d) of the liquid product(s) resulting from the separation stage c) can be carried out.

[0189] Such a stage d) can comprise at least one stage chosen from the list consisting of hydrotreating, steam cracking, fluidized bed catalytic cracking, hydrocracking, deasphalting and the extraction of lubricating oils. These examples of subsequent treatment are not exhaustive.

[0190] This is because the various hydrocarbon products which can result from the separation stage c) can be sent to different processes in the refinery, and the details of all these post-treatments are not described here, being generally known to a person skilled in the art.

[0191] According to an alternative form, the stocks of naphtha, kerosene and diesel type can be upgraded in a refinery for the production of fuels for the motor vehicle industry and the aviation industry, such as, for example, premium-grade gasolines, jet fuels and gas oils, either directly or after an optional hydrotreating.

[0192] According to another alternative form, a part of the gases comprising hydrocarbons with from 2 to 4 carbon atoms, the stocks of naphtha, kerosene and diesel type can be upgraded in a steam cracking unit in order to be able to obtain in particular light olefins which will be able to be used as monomers in the manufacture of polymers.

[0193] According to yet another alternative form, the stocks of naphtha, kerosene and diesel type can be upgraded in a fluidized bed catalytic cracking (FCC for Fluid Catalytic Cracking) unit or also in a hydrocracking unit.

[0194] According to another alternative form, the vacuum distillate can be upgraded in the hydrocracking unit.

[0195] According to another alternative form, the atmospheric residue and / or vacuum residue (unconverted) can be sent to a catalytic cracking (FCC) process, a hydrocracking or also a deasphalting.

[0196] According to another alternative form, the atmospheric residue fraction and / or the vacuum residue fraction can be used as marine fuels having a low sulfur content, in particular distillates for maritime use and / or residual fuels for maritime use, generally known as bunker fuel oil. In particular, it is possible to produce a residual fuel for maritime use having a low sulfur content without the need to add a flux. The fluxes, generally chosen from the light cut oils from a catalytic cracking (LCO for Light Cycle Oil according to the FCC term), the heavy cut oils from a catalytic cracking (HCO for Heavy Cycle Oil according to the FCC term), the residue of a catalytic cracking, a kerosene, a gas oil, a vacuum distillate and / or a decanted oil, are generally added to lower the viscosity of a bunker fuel oils. The presence of a pyrolysis oil as co-feedstock in the treatment of a heavy feedstock of fossil origin makes it possible in particular to directly obtain a fuel oil observing the specifications in terms of sulfur, of sediments and of viscosity, without the need to add a flux. The specifications in terms of sulfur for a fuel oil are a sulfur content of less than 0.5% by weight / ppm (ISO 8217). RMG 380 is the commonest grade of bunker fuel oil according to Standard ISO 8217 and the specification in terms of viscosity for the bunker fuel oil of RMG 380 grade is a viscosity of less than 380 cST at 50° C. Another very restrictive recommendation is the content of sediments after ageing according to ISO 10307-2 (also known under the name of IP390), which has to be less than or equal to 0.1%.LIST OF THE FIGURES

[0197] FIG. 1 diagrammatically illustrates an embodiment of the process according to the invention.

[0198] FIG. 1 describes a simplified diagram for the implementation of the series of reactors of the invention without limiting the scope thereof. For the sake of simplicity, only the reactors are represented but it is understood that all the items of equipment necessary for the functioning are present (drums, pumps, exchangers, ovens, columns, and the like). Only the main streams containing the hydrocarbons are represented but it is understood that hydrogen-rich gas streams (make-up or recycle) can be injected at the inlet of each catalytic bed or between two beds.

[0199] The feedstock comprising a heavy fraction of hydrocarbons 1 and a minor fraction of plastic and / or tyre and / or SRF pyrolysis oil 2, optionally pretreated (not represented), enters a fixed bed reaction unit comprising permutable guard reactors constituted of the reactors Ra and Rb, in order to carry out a hydrodemetallization stage a). The fraction of pyrolysis oil can be premixed with the heavy fraction of hydrocarbons of the feedstock before entry into the first hydrodemetallization reactor. Another alternative form is the separate injection of the fraction of pyrolysis oil and of the heavy fraction of hydrocarbons into the first hydrodemetallization reactor (injection not represented). The effluent 3 from the stage a) of hydrodemetallization in permutable guard reactors is sent to a fixed bed reaction section constituted of the reactors R1, R2 and R3, in order to carry out the hydrotreating stage b). The fixed bed hydrotreating reactors can, for example, be respectively charged with hydrodemetallization, transition and hydrodesulfurization catalysts. The effluent 4 from the fixed bed hydrotreating stage is sent to a separation section 5 in order to proceed to the separation stage and to separate a gaseous effluent 6 and at least one liquid product 7.

[0200] The operation of the permutable reactors is as follows:

[0201] Each reactor Ra and Rb can be placed off-line so as to change the catalyst without shutting down the remainder of the unit. This change of catalyst (rinsing, discharging, recharging, sulfiding) is generally made possible by a conditioning section which is not represented. In sequence 1, the feedstock passes through the reactors Ra and Rb, then R1, R2 and R3. When the catalyst of the reactor Ra is no longer sufficiently active (poisoning by the metals and coking) and / or when the clogging reaches an excessively high pressure drop, permutation for change of catalyst occurs. In sequence 2, the reactor Ra is placed off-line, the feedstock directly enters the reactor Rb, then passes through R1, R2 and R3. During this sequence 2, the spent catalyst from the reactor Ra is discharged and the reactor Ra is recharged with a fresh catalyst. In sequence 3, the reactor Ra containing the fresh catalyst is placed on-line so that the feedstock passes through first the reactor Rb containing a partially spent catalyst, then the reactor Ra, then R1, R2 and R3. When the catalyst of the reactor Rb is no longer sufficiently active and / or when the clogging reaches an excessively high pressure drop, another permutation for change of catalyst occurs. During this sequence 4, the spent catalyst from the reactor Rb is discharged and the reactor Rb is recharged with a fresh catalyst; the feedstock directly enters the reactor Ra, then passes through R1, R2 and R3. In sequence 5, the reactor Rb containing the fresh catalyst is placed on-line so that the feedstock passes through first the reactor Ra containing a partially spent catalyst, then the reactor Rb, then R1, R2 and R3. As the sequence 5 is identical to the sequence 1, this testifies to the cyclic nature of the proposed operation.

[0202] Examples of sequences which can be produced according to FIG. 1 are given in the following table:TABLE 1HDM in permutable reactorsHDT in a fixed bedSequenceOff-lineHDM1HDM2HDMTransitionHDS1—RaRbR1R2R32Ra—RbR1R2R33—RbRaR1R2R34Rb—RaR1R2R35—RaRbR1R2R3

[0203] Analogously, there may be more than 2 permutable reactors in the section for hydrodemetallization in permutable reactors. Analogously, there may be more or less than 3 reactors for hydrotreating in a fixed bed, the representation by R1, R2 and R3 being given purely by way of illustration.Analysis Methods Used

[0204] The analysis methods and / or standards used to determine the characteristics of the various streams, in particular the feedstock to be treated and effluents produced, are known to a person skilled in the art. They are in particular listed in Table 2 below by way of information. Other methods reputed to be equivalent can also be used, in particular equivalent IP, EN or ISO methods.TABLE 2DescriptionMethodDensity @ 15° C.ASTM D4052Sulfur ContentISO 20846Nitrogen ContentASTM D4629Bromine Number (Content of Olefins)ASTM D1159Content of Diolefins from the Maleic AnhydrideMAV Method (1)ValueContent of Oxygen-Containing MoleculesInfraredContent of ParaffinsUOP990-11Content of Naphthenes and OlefinsUOP990-11Content of AromaticsUOP990-11Content of HalogensASTM D7359Content of ChlorideASTM D7536Content of Metals:ASTM D5185PFeSiNaContent of C7 AsphaltenesASTM D6560Conradson CarbonASTM D482ViscosityASTM D3236(1) MAV method described in the paper: C. López-García et al., Near Infrared Monitoring of Low Conjugated Diolefins Content in Hydrotreated FCC Gasoline Streams, Oil & Gas Science and Technology - Rev. IFP, Vol. 62 (2007), No. 1, pp. 57-68EXAMPLES

[0205] The examples below are targeted at showing certain performance qualities of the process according to the invention.

[0206] In these examples, the possibility of co-treatment of a plastic pyrolysis oil in a treatment process of Hyvahl® type which removes the impurities naturally present in heavy feedstocks of fossil origin is illustrated. The hydrotreated effluents can be used as stocks for manufacturing fuels, lubricants or any other product conventionally resulting from the refining of oil. The ability of the supported catalyst present in the Hyvahl® process to capture the impurities present in the pyrolysis oil and thus to upgrade this feedstock while facilitating the post-treatment of the effluents resulting from the hydrotreating of the heavy feedstock which are at the sulfur (0.5% by weight) and viscosity (380 cSt at 50° C.) specifications required by Standard ISO 8217 for a bunker fuel oil of RMG 380 type is also shown.

[0207] Example 1 is a comparative example illustrating the performance qualities of the treatment process for a reference feedstock (vacuum residue) without plastic pyrolysis oil.

[0208] Example 2 illustrates the performance qualities of a treatment process with a feedstock comprising a fraction of plastic pyrolysis oil and a fraction of the reference feedstock (vacuum residue) used in Example 1. The mixture was employed during a pre-stage of homogenization of the medium (optional stage).Feedstock:

[0209] The heavy fraction (I) of the feedstock is a vacuum residue originating directly from the distillation of a crude oil (“straight-run” (SR-VR)). The fraction of plastic pyrolysis oil (II) of the feedstock is a pyrolysis oil resulting from a mixture of plastics and containing a high level of impurities.

[0210] The main characteristics of these two fractions of the feedstock are presented in Table 3 below.TABLE 3Feedstock for thehydroconversionFraction IFraction IIFeedstock—SR-VRPlasticpyrolysis oilDensity—1.0030.835Bromine Numberg / 100 g—59MAVmg / g—36ViscositycSt499 (100° C.)2.5 (40° C.)Conradson Carbon% by weight16.5—C7 Asphaltenes% by weight5.7—Nickel + Vanadiumppm by weight257<DL*Sippm by weight<DL*92Chlorineppm by weight2488Nitrogenppm by weight58002109Sulfur—2.56% by135 ppm byweightweightOxygen% by weight0.460.58Hydrogen% by weight10.711.6Content of 180° C.−% by weight050.9Content of 180-350° C.% by weight1.034.2Content of 350-540° C.% by weight20.614.1Content of 540° C.+% by weight84.50.8*DL: Detection Limit

[0211] The treatment process comprises the use of two permutable reactors Ra and Rb in the first hydrodemetallization (HDM) stage upstream of a hydrotreating section composed of 4 fixed bed reactors (R1, R2, R3 and R4). The operating conditions are similar for the two examples and they are summarized in Table 4 below.TABLE 4HSVWABT (° C.)PPH2H2 / HC(h−1)MOR**(MPa)(SL / L)HDM Permutables0.55385151000(Ra and Rb)Hydrotreating in a fixed bed0.19385151000(R1, R2, R3 and R4)**MOR = at the middle of the cycle (Middle of Run)Overall Results and Performance Qualities:

[0212] The results relating to the treatment performance qualities of the VR feedstock with (Example 2) or without (Example 1) plastic pyrolysis oil are described in detail in Table 5 below.TABLE 5Example 2Example 190% VR (Fraction100% VRI) / 10% PyrolysisFeedstock(Fraction I)Oil (Fraction II)Yields (MOR)H2S + NH3% by weight2.42.2C1-C4% by weight3.53.2IP-180° C.% by weight1.13.8180-350°C.% by weight8.112.2350-520°C.% by weight19.820.0520°C.+% by weight66.159.6Total% by weight100.9101.0Properties ofSippm<DL*<DL*the total effluentsChlorineppm<DL*<DL*For a flow rate of feedstock at the inlet typical for a Hyvahl process (300 tonne / h)AtmosphericIP-180° C.tonne / h3.211.3Distillates180-350°C.tonne / h0.010.1Bunker Fuel180-350°C.tonne / h24.226.4Oil350-520°C.tonne / h59.560.1Composition520°C.+tonne / h198.3178.7Fluxtonne / h6.60.0Properties ofViscosity at 50° C.cSt375375the BunkerSulfur% by weight0.470.42Fuel OilSediments (IP390)% by weight<0.1<0.1*DL: Detection Limit

[0213] It is observed that the presence of plastic pyrolysis oil makes it possible to remove the need to add a flux cut to achieve the sulfur and viscosity specifications imposed by Standard ISO 8217 for a bunker fuel oil of RMG 380 type. In addition, in the co-treatment of the plastic pyrolysis oil of Example 2, the formulation of the bunker fuel oil does not require the use of all of the [180-350° C.] cut, unlike what is observed in Example 1. This “excess” cut can thus be sent to the steam cracker with the IP-180° C. cut or be used as stock for the formulation of other fuels.

[0214] It may also be observed that the total effluents resulting from the hydrotreating of the mixture of the VR cut with the plastic pyrolysis oil exhibit contents of Si and Cl below the analytical detection limit, which indicates that the catalysts and the operating conditions employed in the treatment process are suitable for removing the impurities.

Claims

1. A process the treatment of a feedstock comprising a heavy fraction of hydrocarbons of fossil origin having an initial boiling point of at least 340° C. and a final boiling point of at least 550° C. and containing sulfur and nitrogen, and a fraction of plastic and / or tire and / or solid recovered fuel pyrolysis oil, said fraction of pyrolysis oil constituting less than 50% by weight of said feedstock, said process comprising:a) a hydrodemetallization stage carried out in a fixed bed reaction section comprising at least two permutable reactors, said section being fed at least by said feedstock and a gas stream comprising hydrogen, in the presence of at least one hydrodemetallization catalyst, at a temperature between 300 and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1,b) a hydrotreating stage carried out in a reaction section comprising at least one fixed bed reactor, said section being fed at least by said effluent resulting from stage a) and optionally a gas stream comprising hydrogen, in the presence of at least one hydrotreating catalyst, at a temperature between 300 and 500° C., an absolute pressure of between 5 MPa and 35 MPa and an hourly space velocity between 0.1 and 5.0 h−1,c) a stage of separation of the effluent resulting from stage b) carried out in a separation section resulting in a gas fraction and at least one liquid product.

2. The process according to claim 1, further comprising at least one stage a0) of pretreatment of the fraction of plastic and / or tyre tire and / or solid recovered fuel pyrolysis oil, said pretreatment stage being carried out upstream of stage a), and comprising an adsorption stage and / or a filtration stage and / or a centrifugation stage and / or an electrostatic separation stage and / or a stage of scrubbing by means of an aqueous solution and / or a gas stripping stage.

3. The process according to claim 1, rein the fraction of pyrolysis oil constitutes between 1% and 45% by weight of said feedstock.

4. The process according to claim 1, wherein the feedstock is constituted of said fraction of pyrolysis oil and of said heavy fraction of hydrocarbons, said fraction of pyrolysis oil constituting between 1% and 45% by weight of said feedstock, and the heavy fraction of hydrocarbons constituting between 55% and 99% by weight of said feedstock.

5. The process according to claim 1, which the heavy fraction of hydrocarbons is chosen from the list consisting of an atmospheric residue or a vacuum residue resulting from the atmospheric and / or vacuum distillation of a crude oil or of an effluent originating from a thermal conversion, hydrotreating, hydrocracking or hydroconversion unit, an aromatic cut extracted from a unit for the production of lubricants, a deasphalted oil resulting from a deasphalting unit, an asphalt resulting from a deasphalting unit or a residual fraction resulting from direct coal liquefaction.

6. The process according to claim 5, wherein the heavy fraction of hydrocarbons is a vacuum residue and / or an atmospheric residue.

7. The process according to claim 1, wherein the hydrodemetallization catalyst of stage a) comprises from 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO, with respect to the total weight of the catalyst and from 1% to 30% by weight of molybdenum, expressed as molybdenum oxide MoO3, with respect to the total weight of the catalyst, on a mineral support chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals.

8. The process according to claim 1, wherein which the hydrotreating catalyst of stage b) comprises from 0.5% to 10% by weight of nickel, expressed as nickel oxide NiO, with respect to the total weight of the catalyst and from 1% to 30% by weight of molybdenum, expressed as molybdenum oxide MoO3, with respect to the total weight of the catalyst, on a mineral support chosen from the group consisting of alumina, silica, silicas-aluminas, magnesia, clays and the mixtures of at least two of these minerals.

9. The process according to claim 1, wherein said separation section in stage c) comprises means for scrubbing by contact with an aqueous solution.

10. The process according to claim 9, wherein the separation stage c) comprises:c1) a first separation stage carried out at a temperature greater than the precipitation temperature of ammonium halides, in order to obtain at least one first gas fraction and one liquid effluent,c2) a second separation stage, fed by first gas fraction and at least a part of the liquid effluent resulting from stage c1) and an aqueous solution, said stage being carried out at a temperature lower than the precipitation temperature of ammonium halides, in order to obtain at least one second gas fraction, one aqueous effluent and one liquid product.

11. The process according to claim 1, further comprising a stage d) of subsequent treatment of the at least one liquid product resulting from stage c), said stage d) comprising at least one stage chosen from the list consisting of hydrotreating, steam cracking, fluidized bed catalytic cracking, hydrocracking, deasphalting and the extraction of lubricating oils.

12. The process according to claim 1, wherein, in stage a), the fraction of pyrolysis oil and the heavy fraction of hydrocarbons of the feedstock are premixed before they are introduced into one of said permutable reactors.

13. The process according to claim 1, wherein, which, in stage a), the fraction of pyrolysis oil of the feedstock is introduced separately from the heavy fraction of hydrocarbons into one of said permutable reactors.

14. The process Pp according to claim 13, wherein stage a) comprises a stage of preheating said heavy fraction of hydrocarbons, and a stage of preheating the fraction of pyrolysis oil carried out at a lower temperature than that of said heavy fraction of hydrocarbons, before the introduction of the feedstock into one of said permutable reactors.

15. A product obtained by the process according to claim 1.

16. The product according to claim 15, wherein the product has a content of silicon of less than or equal to 10 ppm by weight and / or a content of chlorine element of less than or equal to 10 ppm by weight, with respect to the weight of the product.

17. The process according to claim 1, wherein the fraction of pyrolysis oil is between 2% and 30% by weight of said feedstock.

18. The process according to claim 4, wherein said fraction of pyrolysis oil is between 2% and 30% by of said feedstock.

19. The process according to claim 4, wherein the heavy fraction of hydrocarbons is between 70% and 98% by weight of said feedstock.

20. The process according to claim 13, wherein, in the stage of preheating the heavy fraction of hydrocarbons, the heavy fraction of hydrocarbons is heated to a temperature of between 280° C. and 450° C.

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