WO2025190772A1 - Method for producing bases for petrochemistry comprising fluid catalytic cracking, oligocracking, fixed-bed hydrocracking, catalytic reforming and steam cracking - Google Patents

Abstract

The present invention relates to a method for producing olefins and aromatics from a hydrocarbon feedstock comprising crude oil, the method comprising the following steps: a) an atmospheric distillation step; b) a fluid catalytic cracking step; c) a fixed-bed hydrocracking step; d) a steam cracking step; e) a catalytic reforming step; f) a step of converting and/or separating the aromatics; g) a step of oligomerization and catalytic cracking in one step.

Description

PROCESS FOR PRODUCING BASES FOR PETROCHEMICAL INDUSTRY COMPRISING FLUID CATALYTIC CRACKING, OLIGOCRAKING, FIXED BED HYDROCRACKING, CATALYTIC REFORMING AND STEAM CRACKING

TECHNICAL FIELD

The present invention relates to a process for producing olefins and aromatics for the petrochemical industry from a crude oil feedstock.

PRIOR TECHNIQUE

Improvements in engine power and the gradual electrification of some vehicles have led to a shift in demand for petroleum products, with a tendency to reduce the growth in fuel demand. Conversely, growth in demand for petrochemical bases, particularly olefins, is more sustained. Ethylene and propylene, for example, are highly sought-after olefins, as they are essential intermediates for many petrochemical products such as polyethylene and polypropylene. There is therefore an interest in remodeling refining sites to produce at least some petrochemical bases, or in designing new integrated refining-petrochemical schemes, or in designing sites where most or all of the crude is converted into petrochemical bases.

The main process for the high-yield conversion of hydrocarbon fractions into olefins is steam cracking. The production of the desired olefins is accompanied by co-products, including aromatic compounds and pyrolysis oil, which require purification steps. In addition, the selectivity towards the desired olefins is highly dependent on the quality of the feedstocks introduced into the steam cracking step. There is therefore an interest in identifying new processes for the production of olefins from heavy hydrocarbon fractions in a more efficient, cost-effective manner, and independent of the heavy hydrocarbon fraction being processed, including poor-quality feedstocks for steam cracking.

Furthermore, the main process for the production of aromatic compounds is catalytic reforming, which is generally associated with complex separation and transformation steps in a section called the "aromatic complex". This aromatic complex produces commercial grade aromatic molecules (usually among benzene, toluene, ortho and para xylene), as well as a number of by-products, including raffinate, which can be advantageously used as feedstock for steam cracking. Conversely, steam cracking produces a fraction rich in aromatics that can be usefully recovered in the aromatic complex. It is therefore beneficial to exploit the synergy of steam cracking with the aromatic complex to improve the economic profitability of a petrochemical complex.

Among the processes for converting heavy fractions of atmospheric residue hydrocarbons, fluid catalytic cracking of residues is now a key process in modern refineries to produce olefins and distillates in particular. Due to the impurity content of certain atmospheric residue feedstocks, residue hydrotreatment units are often installed upstream to reduce the impurity content, particularly sulfur, metals and Conradson carbon (CCR). The effluent from the hydrotreatment stage is generally subjected to a separation step to remove atmospheric gases and distillates. The atmospheric residue, hydrotreated if necessary, obtained in the separation step is sent to fluid catalytic cracking.

Fluid catalytic cracking is known by the acronym FCC (abbreviation of the English terminology "Fluid Catalytic Cracking") which can group together several technologies such as for example RFCC (abbreviation of the English terminology "Resid Fluid Catalytic Cracking") marketed under the acronym R2R™ by the company Axens, or high severity fluid catalytic cracking marketed under the acronym HSFCC™ (abbreviation of the English terminology "High Severity Fluid Catalytic Cracking") by the company Axens.

Document W02020205210 discloses a process flowsheet for converting a hydrocarbon feedstock into olefins and/or aromatics by sending this feedstock directly to a steam cracking unit without going through a conventional crude distillation unit. The unit is composed of three stages where for each of them, the feedstock is heated in a convection zone before being separated in a flash drum into a vapor phase sent to the radiation zone of the steam cracking to be cracked or to a conversion, hydrotreatment, hydrocracking or FCC unit, and into a liquid phase sent to the next heating and separation stage or to the residue hydrotreatment/hydrocracking unit for the liquid phase recovered at the last separation stage. The process multiplies the fractionation steps in the steam cracking unit. This document does not disclose any pretreatment (hydrotreatment/hydrocracking) of the feedstocks sent to the steam cracking unit. The liquid fraction at the outlet of the ^3rd and final separation stage corresponding to the heaviest part of the load is sent to a residue hydroconversion unit and not directly to the FCC unit.

Document WO202096979 discloses a process flowsheet for converting a hydrocarbon feedstock comprising an initial separation of the feedstock into two phases: a steam-cracked vapor phase and a liquid phase sent to an FCC. This separation is not carried out in a conventional distillation column but in a separator drum placed downstream of the feedstock heating step which can be carried out in the convection zone of a steam cracker furnace in the presence of an aqueous fluid. This document does not disclose a specific treatment of the diesel cut by hydrocracking to maximize the production of olefins and aromatics. It also does not include the separation of FCC gasoline into light and heavy cuts in order to adapt their treatment according to the downstream units (steam cracking, reforming or aromatics extraction).

WO201659568 discloses a process for producing numerous petrochemical products, including cumene or polycarbonate, from a crude hydrocarbon feedstock. The process includes atmospheric distillation, steam cracking, or FCC units. The feedstock for the FCC unit is a light feedstock such as naphtha or vacuum gas oil, rather than a heavy feedstock such as atmospheric residue. Kerosene and diesel cuts are not converted to naphtha in a hydrocracker to maximize aromatics and olefins production.

WO201894353 discloses a process for converting a crude oil feedstock into light olefins, aromatics, and fuels (such as kerosene, diesel, etc.). This process includes atmospheric distillation, steam cracking, hydrocracking, FCC, reforming, and aromatics extraction steps. The process also includes a vacuum distillation step from which a vacuum diesel cut is withdrawn to be hydrocracked or hydrotreated and then sent to the FCC. This document does not disclose a treatment of the atmospheric residue in the FCC. In addition, this document does not disclose hydrocracking of atmospheric diesel to maximize the production of naphtha to be sent to the steam cracker.

The present invention aims to distinguish itself from prior art petrochemical base production processes by providing a process for converting the majority of a hydrocarbon feedstock comprising crude oil into petrochemical bases. This process includes a step of converting the atmospheric residue using fluid catalytic cracking, a step of oligomerization and catalytic cracking in a single step (also called oligocracking) of the olefins of the FCC and LPG gasoline cuts from the fluid catalytic cracking step as well as, in one embodiment, separate hydrocracking steps treating different distillate cuts depending on their origin for the production of light and/or heavy naphtha for steam cracking and catalytic reforming steps to produce olefins and aromatics.

SUMMARY OF THE INVENTION The present invention relates to a process for producing olefins and aromatics from a hydrocarbon feedstock comprising crude oil, the process comprising the following steps: a) an atmospheric distillation step comprising treating all or part of the hydrocarbon feedstock comprising crude oil in an atmospheric distillation unit, and obtaining a naphtha cut, a diesel cut and an atmospheric residue cut; b) a fluid catalytic cracking (FCC) step comprising the treatment of all or part of the atmospheric residue cut obtained in step a) in an FCC unit comprising a catalytic cracking zone operating in ascending or descending flow containing an FCC catalyst, operating at a temperature at the outlet of the catalytic cracking zone of between 400 and 700°C, at a pressure of the catalytic cracking zone of between 0.1 and 2 MPa, and obtaining an LPG cut, an FCC gasoline cut and a light distillate cut (LCO); c) a fixed-bed hydrocracking step comprising the treatment of all or part of a diesel and/or light distillate (LCO) cut chosen from the cuts obtained in steps a) and b) alone or as a mixture in a hydrocracking unit comprising a reactor containing a hydrocracking catalyst, operated in the presence of hydrogen, at a temperature of between 250 and 480°C, under a pressure of between 2 and 25 MPa, and obtaining a light naphtha cut and a heavy naphtha cut; d) a steam cracking step comprising the treatment of all or part of the naphtha and/or light naphtha and/or heavy naphtha cuts and/or cut essentially comprising propylene and ethylene chosen from the cuts obtained in steps a), c) and g) alone or as a mixture in a steam cracking unit comprising a pyrolysis furnace, and obtaining an olefinic cut; e) a catalytic reforming step comprising the treatment of all or part of the heavy naphtha cut obtained in step c) in a catalytic reforming unit comprising a reactor containing a reforming catalyst, operated under a pressure of between 0.1 and 25 MPa and at a temperature of between 480 and 570°C, and obtaining a reformate cut; f) a step of transformation and/or separation of aromatics comprising the treatment of all or part of the reformate cut obtained in step e) in a unit for transformation and/or separation of aromatics, and obtaining an aromatic cut; g) a step of oligomerization and catalytic cracking in one stage, comprising the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) fluid catalytic cracking in a one-stage oligomerization and catalytic cracking unit comprising a reactor containing a catalyst allowing the oligomerization and catalytic cracking of olefins, operated at a temperature between 400 and 600°C, and at a pressure between 0.1 and 1 MPa, and obtaining a cut essentially comprising propylene and ethylene.

The method according to the present invention has the following advantages:

• the conversion into petrochemical bases (olefins and aromatics) of the majority of the hydrocarbon feedstock comprising crude oil, with a yield greater than 70% by weight, preferably 75% by weight of petrochemical bases relative to the weight of the feedstock.

• Process flexibility allowing the treatment of all heavy hydrocarbon fractions regardless of their origin.

• The flexibility to direct production towards more olefins or, on the contrary, more aromatic compounds, and/or to direct selectivity towards a particular olefin or aromatic, depending on market demand, by adjusting the types of processes to be implemented, the operating parameters and the routing of flows.

• The conversion into cuts that can feed the steam cracking and/or catalytic reforming stages of almost all the effluents obtainable by the distillation, fluid catalytic cracking and hydrocracking units, as well as the recycling of almost all the unwanted cuts obtained in the steam cracking and/or catalytic reforming stages to the fluid catalytic cracking and/or hydrocracking units, thus making it possible to obtain an overall process optimized for the production of petrochemical bases with a high yield from a hydrocarbon feedstock comprising crude oil.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, the expression "between ... and ..." and "between .... and ..." are equivalent and mean that the limit values of the interval are included in the range of values described. If this is not the case and the limit values are not included in the range described, such precision will be provided by the present invention.

For the purposes of the present invention, the different parameter ranges for a given step such as pressure ranges and temperature ranges may be used alone or in combination. For example, for the purposes of the present invention, a range of preferred pressure values may be combined with a more preferred temperature value range. Pressures are given in absolute terms in this application.

In the following, particular embodiments of the invention may be described. They may be implemented separately or combined with each other, without limitation of combinations when technically feasible.

Throughout this text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief D.R. Lide, 81st edition, 2000-2001). For example, group VIIIB according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IIIPAC classification, and group IB according to the CAS classification corresponds to the metals in column 11 according to the new IIIPAC classification.

The term gas cut means: a cut comprising essentially light gases or C1 to C4 alkanes, i.e. methane, ethane, propane, iso-butane and normal-butane.

LPG cut means: a cut comprising mainly light gases or C3 and C4 alkanes, i.e. propane, iso-butane and normal-butane.

Naphtha cut means: a cut comprising essentially hydrocarbon compounds boiling in a range between 28 and 180°C.

Light naphtha cut means: a cut comprising essentially hydrocarbon compounds boiling in a range between 28 and 101°C.

Heavy naphtha cut means: a cut comprising essentially hydrocarbon compounds boiling in a range between 65 and 180°C.

The cut-off point between light and heavy naphtha can vary between 65 and 101°C.

Diesel cut means: a cut comprising essentially hydrocarbon compounds boiling in a range between 175 and 350°C.

Kerosene cut means: a cut comprising essentially hydrocarbon compounds boiling in a range between 175 and 220°C.

Atmospheric residue cut means: a cut comprising essentially hydrocarbon compounds boiling above 350°C, and produced by distillation of the crude oil feedstock.

“Essentially comprising” means: whose main constituent(s) in mass is/are.

Purge cut means: a cut from diesel hydrocracking processes comprising mainly hydrocarbon compounds boiling above 175°C. Olefinic fraction means: a fraction comprising more than 99% by weight, preferably more than 99.5% by weight of olefins, preferably having from 2 to 4 carbon atoms.

The term C4 cut means: a cut comprising essentially hydrocarbon compounds having 4 carbon atoms.

Reformate cut means: a cut from the catalytic reformer comprising more than 75% by weight of aromatic hydrocarbon compounds.

Aromatic cut means: a cut comprising more than 99% by weight, preferably more than 99.5% of aromatic hydrocarbon compounds.

A raffinate cut is understood to mean: a cut from the aromatic complex comprising essentially non-aromatic hydrocarbon compounds having 5 to 8 carbon atoms.

Light pyrolysis gasoline cut means: the fraction of the steam cracking effluent containing hydrocarbons with 6 to 8 carbon atoms.

Heavy pyrolysis gasoline cut means: the fraction of the steam cracking effluent containing hydrocarbons with 9 to 10 carbon atoms.

Pyrolysis oil cut means: the fraction of the steam cracking effluent containing hydrocarbons with 11 carbon atoms or more.

Heavy aromatic cut means: a cut from the aromatic complex comprising mainly aromatic compounds with 9 and 10 carbon atoms.

Charge

The process according to the invention is a process for producing olefins and aromatics from a hydrocarbon feedstock comprising crude oil.

Advantageously, the hydrocarbon feedstock consists essentially of crude oil, preferably the hydrocarbon feedstock consists of crude oil.

Crude oil means any type of oil from any geological source and in unrefined form.

Crude oil can be advantageously chosen from Arabian Heavy, Arabian Medium, Arabian Light, Arabian Extra Light, other Gulf crudes, Brent, North Sea crude, North and West African crude, Urals crude, Indonesian crude, Chinese crude, or a mixture of them.

This corresponds advantageously to a crude having the following characteristics:

Density at 15°C less than 1.1

Sulphur content less than 7% by weight Metal content (Nickel + Vanadium) less than 1000 ppm

Asphaltene content (nC7 insoluble) less than 15% by weight

Step a) atmospheric distillation

The process according to the invention comprises a step a) of atmospheric distillation comprising the treatment of all or part of the hydrocarbon feedstock comprising crude oil in an atmospheric distillation unit, and the obtaining of a naphtha cut, a diesel cut and an atmospheric residue cut.

Advantageously, part of the diesel cut is used for the production of low-sulfur fuel oil (or BTS fuel oil).

In one embodiment, in step a) of atmospheric distillation, a gas cut is also obtained. Advantageously, an LPG cut can be separated from the gas cut.

In one embodiment, in step a) of atmospheric distillation of the crude oil feedstock, a kerosene cut is also obtained. Advantageously, part of this kerosene cut is used for the production of a low-sulfur fuel oil (or BTS fuel oil).

Atmospheric distillation of the crude oil feedstock separates the various components based on their evaporation temperature. The crude oil is advantageously desalted, then preheated and injected into a distillation tower and heated to approximately 400°C. The fractions comprising the lightest hydrocarbons are recovered in gaseous form at the top of the column, such as the gas and naphtha fractions. The fractions with an intermediate boiling range, such as the diesel fraction, are withdrawn laterally in the middle section of the tower. The higher boiling fractions, such as the atmospheric residue fraction, remain in the lower part of the tower and are sent to an FCC unit or, optionally, to a residue hydrotreatment stage.

Step b) of fluid catalytic cracking

The process according to the invention comprises a step b) of fluid catalytic cracking comprising the treatment of all or part of the atmospheric residue cut obtained in step a) in an FCC unit comprising a catalytic cracking zone operating in ascending or descending flow containing an FCC catalyst, operating at a temperature at the outlet of the catalytic cracking zone of between 400 and 700°C, preferably between 450 and 650°C, at a pressure of the catalytic cracking zone of between 0.1 and 2 MPa, preferably between 0.15 and 0.5 MPa, and obtaining an LPG cut, an FCC gasoline cut and a light distillate cut (LCO). Advantageously, the catalytic cracking zone operates with a catalyst to feedstock ratio entering said zone of between 1 and 100 wt/wt, preferably between 5 and 80 wt/wt.

Advantageously, the residence time of the catalyst in the catalytic cracking zone is between 0.5 and 20 s, preferably between 1 and 10 s.

In one embodiment, a co-feed may be treated in step b) of fluid catalytic cracking jointly or separately with the atmospheric residue cut obtained in step a) or in one embodiment with the hydrotreated atmospheric residue cut obtained in the optional step k) of residue hydrotreatment. This co-feed may be an effluent recycled at the outlet of another step of the process according to the invention in order to maximize the yield of petrochemical bases and/or to promote the production of one or more recoverable products.

In one embodiment, the co-feed is all or part of the hydrotreated LCO cut obtained in the optional LCO hydrotreatment step I). This option makes it possible to crack the previously hydrotreated LCO cut obtained in step b) without requiring an additional hydrocracking step and to modulate the petrochemical base yields.

In an FCC unit, the heat balance is ensured by the combustion of the coke deposited on the FCC catalyst during the catalytic reaction. This combustion takes place in a regeneration zone by injecting air via a compressor called the main air compressor (MAB for short, an abbreviation of the English terminology for "main air blower").

Advantageously, the FCC catalyst enters the regeneration zone of the reactor with a coke content (defined as the mass of coke over the mass of catalyst) of between 0.5% and 1%, and leaves said zone with a coke content of less than 0.01%. During this step, combustion fumes are generated and exit the regeneration zone at temperatures of between 550 and 850°C, preferably between 600 and 800°C. These fumes will then, depending on the configurations of the unit, undergo a certain number of post-treatments.

The Conradson carbon content of the feedstock entering the reactor (abbreviated as CCR and defined for example by ASTM D 482) provides an estimate of coke production during catalytic cracking. Depending on the Conradson carbon content of the feedstock, the coke yield requires specific unit sizing to satisfy the heat balance.

Thus, when the charge has a CCR leading to a coke content higher than that required to ensure the heat balance, the excess heat must be removed. This can be done, for example, and in a non-exhaustive manner, by installing a heat exchanger. well known to those skilled in the art, which achieves external cooling of a fraction of the catalyst contained in the regenerator by exchange with water, thus leading to the production of high pressure steam.

The FCC catalyst advantageously consists of particles with an average diameter of between 40 and 140 pm, preferably between 50 and 120 pm.

Advantageously, the FCC catalyst comprises a suitable matrix such as alumina, silica or silica-alumina with the presence or absence of a Y-type zeolite dispersed in this matrix.

The FCC catalyst may further comprise a zeolite exhibiting shape selectivity of one of the following structural types: MEL (e.g., ZSM-11), MFI (e.g., ZSM-5), NES, EUO, FER, CHA (e.g., SAPO-34), MFS, MWW. It may also comprise one of the following zeolites: NU-85, NU-86, NU-88, and IM-5, which also exhibit shape selectivity. The advantage of these shape-selective zeolites is the achievement of improved propylene/isobutene selectivity, i.e., a higher propylene/isobutene ratio in the cracking effluents.

Advantageously, the proportion of zeolite exhibiting shape selectivity relative to the total amount of zeolite in the FCC catalyst may vary depending on the feedstocks used in the FCC step and the structure of the desired products. Advantageously, from 0.1% to 60%, preferably from 0.1% to 40%, and in particular from 0.1% to 30% by weight of zeolite exhibiting shape selectivity is used.

Advantageously, the zeolite(s) may be dispersed in a matrix based on silica, alumina or silica-alumina, the proportion of zeolite (all zeolites combined) relative to the weight of the FCC catalyst being between 0.7% and 80% by weight, preferably between 1% and 50% by weight, and more preferably between 5% and 40% by weight.

In the case where several zeolites are used, they can be incorporated into a single matrix or into several different matrices.

In one embodiment, the FCC catalyst used in the catalytic cracking zone may consist of an ultra-stable Y-type zeolite dispersed in an alumina, silica, or silica-alumina matrix, to which a ZSM5 zeolite-based additive has been added, the ZSM5 crystal content in the FCC catalyst being less than 30% by weight.

Said fluid catalytic cracking step can be carried out both with a catalytic cracking zone operating in ascending flow (called "riser" in English terminology), and in units using a catalytic cracking zone operating in descending flow (called "downer" in English terminology). Preferably the catalytic cracking zone operates in downward flow like the HSFCC high severity fluid catalytic cracking technology marketed under the acronym HSFCC™ (abbreviation of the Anglo-Saxon terminology "High Severity Fluid Catalytic Cracking") by the company Axens.

Generally speaking, the fluid catalytic cracking process allows the conversion of heavy hydrocarbon feedstocks into lighter hydrocarbon fractions ranging from dry gases to a conversion residue. The following cuts can be advantageously distinguished among the effluents, which are conventionally defined according to their composition or their boiling temperature (standard cut points given for information purposes):

- dry and acid gases (mainly: H2, H2S, methane, ethane),

- an LPG cut containing C3 and C4 hydrocarbon compounds,

- an FCC gasoline cut containing at least 80% of hydrocarbon compounds having a boiling point between 30 and 220°C (standard cutting point), sometimes separated into light FCC gasoline known as LCN ("Light Cracked Naphtha" according to Anglo-Saxon terminology) and heavy FCC gasoline known as HCN ("Heavy Cracked Naphtha" according to Anglo-Saxon terminology), the cutting point between LCN and HCN being able to vary between 65 and 101 °C,

- a light distillate cut known as LCO ("Light Cycle Oil" in English terminology) containing at least 80% of hydrocarbon compounds having a boiling point between 220°C and 360°C,

- a heavy distillate cut sometimes known as HCO ("heavy Cycle Oil" in English terminology) containing at least 80% hydrocarbon compounds with a boiling point between 360°C and 440°C,

- possibly an FCC residue ("slurry" according to Anglo-Saxon terminology) which is generally purified of the catalyst particles it contains to obtain a clarified oil ("clarified oil" or CO according to Anglo-Saxon terminology) or a decanted oil ("decanted oil" or DO according to Anglo-Saxon terminology). This residue contains at least 80% of hydrocarbon compounds having a boiling point above 440°C.

In one embodiment, when the optional residue hydrotreatment step k) is implemented, the atmospheric residue cut treated in fluid catalytic cracking step b) is the hydrotreated atmospheric residue cut obtained in step k).

In one embodiment, in step b) of fluid catalytic cracking, a cut is further obtained comprising essentially C1 and C2 hydrocarbon compounds. In one embodiment, in step b) of fluid catalytic cracking, a heavy oil cut is also obtained. Advantageously, this heavy oil cut is used for the production of a low-sulfur fuel oil (or BTS fuel oil).

The term heavy oil is used here to define any heavy cut resulting from step b) of fluid catalytic cracking, and containing at least 80% of hydrocarbon compounds having a boiling point above 360°C. It is understood that this cut may undergo a catalyst particle separation step.

Stage c) fixed bed hydrocracking

The process according to the invention comprises a fixed-bed hydrocracking step c) comprising the treatment of all or part of a diesel and/or light distillate (LCO) cut chosen from the cuts obtained in steps a) and b) alone or as a mixture in a hydrocracking unit comprising a reactor containing a hydrocracking catalyst, operated in the presence of hydrogen, at a temperature between 250 and 480°C, preferably between 300 and 420°C, under a pressure between 2 and 25 MPa, and obtaining a light naphtha cut and a heavy naphtha cut.

Advantageously, step c) is carried out at an hourly volumetric velocity, defined as being the ratio between the total volumetric flow rate of the treated feedstock and the total volume of catalyst and noted WH (or LHSV liquid hourly space velocity according to English terminology), of between 0.3 and 6 h ^-1 , preferably between 1 and 3 h ^-1 .

Advantageously, step c) is carried out at a hydrogen/hydrocarbon volume coverage (denoted H2/HC) of between 100 and 2000 Nm ³ /m ³ (normal cubic meters (Nm ³ ) per cubic meter (m ³ )).

Preferably, the hydrocracking catalyst is chosen from conventional hydrocracking catalysts known to those skilled in the art.

Advantageously, the hydrocracking catalyst is of the bifunctional type combining an acid function with a hydrogenating function. The acid function is provided by supports with large surfaces (generally 150 to 1200 m ² .g- ¹ ) having a surface acidity, such as halogenated aluminas (chlorinated or fluorinated in particular), combinations of boron and aluminum oxides, amorphous silica-aluminas and/or zeolites. The hydrogenating function is provided either by one or more metals from group VIIIB, or by a combination of one or more metals from group VI B and one or more metals from group VIIIB. Preferably, the hydrocracking catalyst comprises a hydrogenating function composed of one or more metals from group VIB and one or more metals from group VI 11 B, taken alone or as a mixture, said catalyst being a sulfide phase catalyst.

The metal(s) from group VIB are advantageously chosen from chromium, molybdenum and tungsten, alone or as a mixture and preferably chosen from molybdenum and tungsten. Preferably, the content of metal from group VIB in the hydrocracking catalyst is advantageously between 5 and 35% by weight and preferably between 10 and 30% by weight, very preferably between 15 and 22% by weight, the percentages being expressed as percentage by weight of oxides.

The metal(s) of group VIIIB are advantageously chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, and preferably from cobalt or nickel. Preferably, the content of metal of group VIIIB in the hydrocracking catalyst is advantageously between 0.5 and 15.0% by weight and preferably between 2.0 and 10.0% by weight, very preferably between 2.5 and 6.0% by weight, the percentages being expressed as percentage by weight of oxides.

The hydrocracking catalyst may optionally comprise at least one promoter element deposited on the catalyst selected from the group consisting of phosphorus, boron and silicon, optionally one or more elements from group VI IA (chlorine, fluorine preferred), optionally one or more elements from group VIIB (manganese preferred), and optionally one or more elements from group VB (niobium preferred).

Preferably, the hydrocracking catalyst comprises an acid function chosen from alumina, silica alumina and zeolites, preferably chosen from Y zeolites and preferably chosen from silica alumina and zeolites.

In one embodiment, fixed bed hydrocracking step c) further comprises the treatment of all or part of the heavy pyrolysis gasoline cut obtained in steam cracking step d).

In one embodiment, in step c) of fixed bed hydrocracking, when the optional step k) of residue hydrotreatment is implemented, the diesel cut can also be chosen in step k).

In one embodiment, in hydrocracking step c), the diesel and/or LCO and heavy pyrolysis gasoline cuts are treated jointly in the same hydrocracking section, or separately in separate hydrocracking sections.

Advantageously, hydrocracking step c) comprises the treatment of all or part of the heavy pyrolysis gasoline cut from steam cracking step d) and/or a first part of the diesel cut from step a) of atmospheric distillation in a first hydrocracking section c-S1), and the treatment of all or part of the light distillate cut (LCO) obtained in step b) of fluid catalytic cracking and/or all or part of the diesel cut obtained in the optional step k) of residue hydrotreatment and/or a second part of the diesel cut from step a) of atmospheric distillation in a second hydrocracking section c-S2). This embodiment makes it possible to have two sections of equivalent capacity, and makes it possible to dilute the olefins contained in the LCO cut in order to better control the exotherms. This configuration also makes it possible to optimize the operating conditions applied to each of the feeds, and consequently, to maximize the yield of recoverable products from the complex, and/or to minimize the catalytic cost of the whole.

Advantageously, a hydrocracking unit consists of a hydrotreatment reactor followed by two hydrocracking reactors.

In one embodiment, in step c) of fixed bed hydrocracking, a gas cut is also obtained. Advantageously, an LPG cut can be separated from the gas cut.

In one embodiment, in step c) of fixed bed hydrocracking, a purge cut is also obtained. Advantageously, this purge cut is used for the production of low-sulfur fuel oil (or BTS fuel oil).

Step d) of steam cracking

The process according to the invention comprises a step d) of steam cracking comprising the treatment of all or part of the naphtha and/or light naphtha and/or heavy naphtha cuts and/or cuts essentially comprising propylene and ethylene chosen from the cuts obtained in steps a), c) and g) alone or as a mixture in a steam cracking unit comprising a pyrolysis furnace, and the obtaining of an olefinic cut.

The steam cracking step d) advantageously consists of the non-catalytic decomposition under the combined effect of high temperature and low pressure in the presence of water vapor, of saturated hydrocarbons, in order to produce aliphatic or aromatic unsaturated hydrocarbon fractions. Said fractions are then used for the synthesis of a large number of products, for example polyethylene or polypropylene. In the case of the process according to the invention, the steam cracking step d) advantageously makes it possible to produce mainly aliphatic unsaturated hydrocarbons.

The operating conditions are adjusted according to the nature of the feedstock entering the steam cracking unit and the yields targeted for each of the main products. Advantageously, the residence time in the pyrolysis furnace is limited in order to limit the formation of heavy products. In addition, the effluent is quenched in order to freeze the composition of the effluent at the outlet of the furnace.

Advantageously, the temperature at which the pyrolysis oven is operated depends on the nature of the load.

Advantageously, the steam cracking stage is implemented in a unit which consists of a number of pyrolysis furnaces, quenching boilers and a fractionation train. All or part of the steam cracking feed enters the hot section of the unit through the convection zone of the furnace where it is preheated, then it is mixed with the water vapor also preheated in this same zone; the hydrocarbons and the water then pass through the actual radiation zone of the furnace where the rapid rise in temperature and the pyrolysis reactions take place. At the outlet of the furnace, in order to avoid any subsequent reaction, the effluents are frozen in their kinetic possibilities of evolution by a sudden quench generally carried out in two stages: an initial indirect quench with water, followed by a direct quench using the heavy residue by-product of pyrolysis. The effluents and possibly part of the steam cracking feed are then transferred to a primary fractionation tower which separates at the bottom a heavy cut called "pyrolysis oil" and, by withdrawal, a part of the "pyrolysis gasoline" cut and water, while the light pyrolysis products exit at the top in gaseous form. After compression, washing with soda (intended to eliminate H2S and acid gases) and drying, these light effluents then enter the cold section of the unit which can be designed in various ways, but which ensures separation into various cuts of interest.

Advantageously, when the feedstock treated in the steam cracking unit is a naphtha cut and/or light naphtha and/or heavy naphtha and/or raffinate, the residence time of the incoming feedstock is between 0.1 and 0.4 seconds, the temperature at the tube outlet is between 700 and 900°C, preferably between 780 and 880°C, and the steam/feedstock ratio is between 0.2 and 1 kg/kg.

In one embodiment, steam cracking step d) further comprises the treatment of all or part of a gas cut chosen from the cuts obtained in steps a), c) and e) alone or as a mixture.

In one embodiment, steam cracking step d) further comprises the treatment of all or part of the cut essentially comprising C1 and C2 hydrocarbon compounds obtained in step b). In one embodiment, steam cracking step d) further comprises the treatment of all or part of the cut essentially comprising hydrocarbon compounds having from 4 to 6 carbon atoms (C4-C6) obtained in step g).

When the optional residue hydrotreatment step k) is implemented, the gas cut can also be chosen in step k).

When the optional naphtha hydrotreatment step i) is implemented, the gas cut can also be chosen in step i).

When the optional LCO hydrotreatment step I) is implemented, the gas cut can also be chosen in step I).

In one embodiment, steam cracking step d) further comprises the treatment of all or part of an LPG fraction chosen from the fractions obtained in steps a, c), e), f), k), i) and I) alone or as a mixture.

Advantageously, when an LPG cut is processed, the residence time of the incoming charge is between 0.1 and 0.4 seconds, the temperature at the tube outlet is between 700 and 1000°C, preferably between 800 and 900°C, and the steam/charge ratio is between 0.2 and 0.8 kg/kg.

In one embodiment, steam cracking step d) further comprises the treatment of all or part of the ethane fraction obtained in step f).

Advantageously, when the ethane fraction is treated, the residence time of the incoming charge is between 0.15 and 0.6 seconds, the temperature at the tube outlet is between 700 and 1000°C, preferably between 800 and 900°C, and the steam/charge ratio is between 0.1 and 0.6 kg/kg.

In one embodiment, step d) of steam cracking further comprises the treatment of all or part of the raffinate cut obtained in step f) of transformation and/or separation of aromatics.

In one embodiment, in step d) of steam cracking, when the optional step i) of naphtha hydrotreatment is implemented, the naphtha cut is the hydrotreated naphtha cut obtained in step i) of naphtha hydrotreatment.

In one embodiment, when the optional naphtha hydrotreatment step i) is implemented, the steam cracking step d) further comprises the treatment of all or part of the hydrotreated light naphtha and/or hydrotreated heavy naphtha and/or hydrotreated LCN cut obtained in the optional naphtha hydrotreatment step i). In one embodiment, steam cracking step d) further comprises the treatment of all or part of the naphtha cut obtained in the optional LCO hydrotreatment step I).

In one embodiment, steam cracking step d) further comprises the treatment of all or part of the raffinate concentrated in non-aromatic compounds and C11 + aromatics obtained in the optional liquid-liquid extraction step h).

In one embodiment, steam cracking step d) further comprises the treatment of all or part of the propane cut obtained in the optional propylene recovery step j).

In one embodiment, the different cuts are treated simultaneously or preferably separately in the steam cracking unit. When they are treated separately, they are treated under different operating conditions depending on the nature of the cut to be treated.

In one embodiment, in step d) of steam cracking, a pyrolysis oil cut is also obtained. Advantageously, this pyrolysis oil cut is used for the production of low-sulfur fuel oil (or BTS fuel oil).

In one embodiment, in step d) of steam cracking, a light pyrolysis gasoline cut is also obtained.

In one embodiment, in step d) of steam cracking, a heavy pyrolysis gasoline cut is also obtained.

In one embodiment, in step d) of steam cracking, a cut comprising H2, H2S, CO and CH4 is further obtained.

In one embodiment, in step d) of steam cracking, a C4 cut is also obtained.

In one embodiment, in step d) of steam cracking, the olefinic fraction is ethylene.

In one embodiment, in step d) of steam cracking, the olefinic fraction is propylene.

In one embodiment, in step d) of steam cracking, the olefinic fraction is butadiene.

In one embodiment, in step d) of steam cracking, the olefinic cut is butene- 1.

In one embodiment, in step d) of steam cracking, the olefinic cut is butene-2. In one embodiment, in step d) of steam cracking, the olefinic fraction is isobutene.

In one embodiment, in step d) of steam cracking, the olefinic fraction is isoprene.

Step e) of catalytic reforming

The process according to the invention comprises a step e) of catalytic reforming comprising the treatment of all or part of the heavy naphtha cut obtained in step c) in a catalytic reforming unit comprising a reactor containing a reforming catalyst, operated under a pressure of between 0.1 and 25 MPa and at a temperature of between 480 and 570°C, and obtaining a reformate cut. The objective of catalytic reforming is to transform the naphthenic constituents and part of the paraffinic constituents (with a low octane number) into aromatic constituents with a high octane number. The catalytic reforming unit consists mainly of a series of three or more reactors containing one or more reforming catalysts and a separator for separating the different products at the outlet of the reactors. The catalyst used may be sensitive to the presence of sulfur and nitrogen products, which is why the inlet charge is advantageously free of sulfur, nitrogen and their derivatives.

The reaction is an endothermic reaction. The hydrocarbons of the heavy naphtha fraction (notably paraffins and naphthenes) are transformed during this process into aromatic hydrocarbons and branched paraffins.

Advantageously, the hydrogen/hydrocarbon molar ratio of the incoming feedstock is between 0.8 and 8 mol/mol.

Advantageously, the weight hourly space velocity (WHSV) defined as the ratio between the total mass flow rate of the treated feedstock and the total mass of catalyst in the incoming feedstock is between 0.1 and 10 h ^-1 , preferably between 0.5 and 6 h ^-1 .

Advantageously, the reforming catalyst comprises an active phase comprising at least one metal chosen from nickel, ruthenium, rhodium, palladium, iridium or platinum, and at least one promoter chosen from rhenium, tin, germanium, cobalt, nickel, iridium, rhodium or ruthenium. Preferably, the reforming catalyst comprises an active phase comprising platinum and tin. The amount of metal is between 0.02 and 2% by weight, preferably between 0.05 and 1.5% by weight, even more preferably between 0.1 and 0.8% by weight relative to the total weight of the catalyst. Preferably, the reforming catalyst comprises a support chosen from alumina, silica-alumina or silica. Preferably, the support is based on alumina. In one embodiment, step e) of catalytic reforming further comprises the treatment of all or part of the cut essentially comprising hydrocarbon compounds having 7 or more carbon atoms (C7+) obtained in step g).

In one embodiment, step e) of catalytic reforming further comprises the treatment of all or part of the hydrotreated heavy naphtha cut obtained in the optional step i) of naphtha hydrotreatment.

In one embodiment, step e) of catalytic reforming further comprises the treatment of all or part of the naphtha cut obtained in the optional step I) of LCO hydrotreatment.

In one embodiment, step e) of catalytic reforming further comprises the treatment of all or part of the raffinate concentrated in non-aromatic compounds and in aromatic compounds with 11 carbons and more (C11+) obtained in the optional step h) of liquid-liquid extraction.

In one embodiment, in step e) of catalytic reforming, a gas cut is also obtained. Advantageously, an LPG cut can be separated from the gas cut.

In one embodiment, in step e) of catalytic reforming, a hydrogen cut is also obtained.

Step f) of transformation and/or separation of aromatics

The process according to the invention comprises a step f) of transformation and/or separation of the aromatics comprising the treatment of all or part of the reformate cut obtained in step e) in a unit for transformation and/or separation of the aromatics, and the obtaining of an aromatic cut.

The objective of this step is twofold:

Convert aromatic C9s and possibly aromatic C10s into benzene, toluene, ortho xylene and para xylene,

- Adjust the proportions of these different molecules by adjusting the number and position of the methyl substituents on the aromatic rings.

The processes advantageously used to carry out this step are described below. The judicious choice of catalysts and operating conditions advantageously makes it possible to minimize yield losses:

Less than 5% loss of methyl groups

Less than 5% loss of aromatic cycles This step advantageously takes place within a unit comprising an aromatic complex which constitutes a set of steps of separation, purification and conversion of aromatic molecules present in the reformate.

The objective of an aromatic complex is to produce with very high purity (compatible with polymerization) benzene, para-xylene, and sometimes toluene and ortho-xylene, as well as heavy aromatics, from fractions rich in aromatics such as reformate or pyrolysis gasoline. Advantageously, in a first step, olefins and non-aromatics are removed in units such as earth treatment, hydrogenation units, extractive distillations or liquid-liquid extraction units. Advantageously, in a second step, a separation train, composed of different distillation columns, produces benzene, toluene, an aromatics cut containing 8 carbon atoms (or A8 cut), and one or more cuts containing aromatics with more than 9 carbon atoms.

Advantageously, the A8 cut enters the “xylene loop”, in which paraxylene is separated from the other xylene isomers either in a liquid-liquid extraction unit based on simulated moving bed (SMB) technology, or in a crystallization unit. The other constituents of the A8 cut (ortho and meta xylene, ethyl benzene) are advantageously isomerized or converted using a liquid-phase or gas-phase isomerization unit, and return to the separation train. All or part of the toluene is advantageously converted in transalkylation, disproportionation, or methyl-alkylation units to produce more C8 aromatics and benzene. Aromatics containing 9 or 10 carbon atoms can advantageously be sent to a transalkylation unit to produce more 8-carbon aromatics. As for the heavier aromatics (11 carbon atoms and more), they are considered by-products, and advantageously exported as gasoline base.

In one embodiment, step f) of transformation and/or separation of aromatics further comprises the treatment of all or part of the light pyrolysis gasoline cut obtained in step d) of steam cracking, preferably together with all or part of the reformate cut.

In one embodiment, step f) of transformation and/or separation of the aromatics further comprises a treatment of all or part of the extract concentrated in aromatic compounds of 6 to 10 carbon atoms (C6-C10) obtained in the optional step h) of liquid-liquid extraction, preferably jointly with the reformate cut. In one embodiment, in step f) of transformation and/or separation of the aromatics, an LPG cut is also obtained.

In one embodiment, in step f) of transformation and/or separation of the aromatics, an ethane cut is also obtained.

In one embodiment, in step f) of transformation and/or separation of the aromatics, a raffinate cut is also obtained, preferably rich in paraffins.

In one embodiment, in step f) of transformation and/or separation of the aromatics, a heavy aromatic cut is also obtained. Advantageously, this heavy aromatic cut is used for the production of a low-sulfur fuel oil (or BTS fuel oil).

In one embodiment, in step f) of transformation and/or separation of the aromatics, the aromatic fraction is benzene.

In one embodiment, in step f) of transformation and/or separation of the aromatics, the aromatic cut is paraxylene.

It is also possible to produce other aromatic fractions such as toluene or orthoxylene.

Step g) of oligomerization and one-step catalytic cracking (oligocracking)

The process according to the invention comprises a step g) of oligomerization and catalytic cracking in one stage, comprising the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking in a unit of oligomerization and catalytic cracking in one stage comprising a reactor containing a catalyst allowing the oligomerization and catalytic cracking of olefins, operated at a temperature between 400 and 600°C, preferably between 450°C and 580°C, and at a pressure between 0.1 and 1 MPa, preferably between 0.1 and 0.5 MPa, and obtaining a cut essentially comprising propylene and ethylene.

In one embodiment, in step g), a cut is also obtained which essentially comprises hydrocarbon compounds having from 4 to 6 carbon atoms (C4-C6). Advantageously, all or part of the C4-C6 cut is recycled at the inlet of step g). The recycling flow rate of the C4-C6 cut obtained in step g) relative to the flow rate of the incoming feed in step g) can vary in a ratio of 1 to 5, and preferably of 2 to 4.

In one embodiment, in step g), a cut is further obtained comprising essentially hydrocarbon compounds having 7 carbon atoms or more (C7+). In one embodiment, step g) further comprises the treatment of all or part of the C4 cut obtained in step d) of steam cracking.

Step g) of oligomerization and catalytic cracking in one step is advantageously carried out in the presence of a catalyst allowing the oligomerization and catalytic cracking of olefins comprising a zeolite having shape selectivity, this zeolite having an Si/Al atomic ratio of between 50 and 500, and preferably of between 75 and 150.

In one embodiment, the catalyst for oligomerization and catalytic cracking of olefins comprises a shape-selective zeolite belonging to a first group consisting of one of the following structural types: MEL, MFI, NES, EUO, FER, CHA, MFS, MWW, or consisting of any mixture of the elements of this first group.

In another embodiment, the catalyst for the oligomerization and catalytic cracking of olefins comprises a shape-selective zeolite belonging to a second group consisting of the following zeolites: Nll-85, Nll-86, Nll-88 and IM-5 or any mixture of the elements of this second group.

One of the advantages of these zeolites exhibiting shape selectivity is that it leads to better propylene/isobutene selectivity, i.e. a higher propylene/isobutene ratio in the effluents of said single-stage oligomerization and catalytic cracking unit.

The zeolite used in the catalyst for the oligomerization and catalytic cracking of olefins can be dispersed in a matrix based on silica, zirconia, alumina or silica alumina, the proportion of zeolite generally being between 15% and 90% by weight, preferably between 30% and 80% by weight.

In particular, one of the following commercial ZSM-5 zeolites can be used:

- CBV 28014 (Si/AI ratio: 140), and CBV 1502 (Si/AI atomic ratio: 75) from Zeolyst International, Valley Forge PA., 19482 USA,

- ZSM-5 Pentasil with an atomic ratio of Si/AI 125 from Süd-Chemie (Munich, Germany).

The catalyst enabling the oligomerization and catalytic cracking of olefins is generally used in a moving bed, preferably in the form of beads with a diameter generally between 1 mm and 3 mm.

The catalyst for oligomerization and catalytic cracking of olefins can also be used in a fixed bed, in which case the reactor used is alternately in the reaction phase and then in the regeneration phase. The regeneration phase typically includes a combustion phase of the carbon deposits formed on the catalyst, for example using an air/nitrogen mixture or oxygen-depleted air (for example by flue gas recirculation), or simply air.

According to one embodiment, the regeneration of the catalyst allowing the oligomerization and catalytic cracking of olefins is carried out at a temperature between 400°C and 650°C, and at a pressure advantageously close to the pressure used for the oligomerization and catalytic cracking reaction in one step.

Advantageously, step g) is carried out at a WH of between 1 h ^-1 and 10 h ^-1 .

Step g) comprises the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking, i.e. the LPG and FCC gasoline cuts may be sent directly to the single-stage oligomerization and catalytic cracking unit or may undergo one or more treatment/transformation steps upstream of the single-stage oligomerization and catalytic cracking step.

In one embodiment, step g) of oligomerization and one-step catalytic cracking comprises the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking by sending all or part of said LPG and FCC gasoline cuts into a one-step oligomerization and catalytic cracking unit.

In one embodiment, when an embodiment of the optional naphtha hydrotreatment step i) is implemented, the one-step oligomerization and catalytic cracking step g) comprises the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in the fluid catalytic cracking step b) by sending all or part of the LPG cut obtained in the fluid catalytic cracking step b) and all or part of the selectively hydrogenated light FCC gasoline (LCN) cut obtained in step i) into a one-step oligomerization and catalytic cracking unit.

In one embodiment, when the optional step j) of propylene recovery is implemented, the step g) of oligomerization and one-step catalytic cracking comprises the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking by sending all or part of the C4 cut obtained in step j) and all or part of the FCC gasoline cut obtained in step b) of fluid catalytic cracking into a one-step oligomerization and catalytic cracking unit.

In one embodiment, when an embodiment of the optional step i) of naphtha hydrotreatment and the optional step i) of propylene recovery are carried out, the step g) of oligomerization and one-step catalytic cracking comprises the treatment of the olefins contained in the LPG and gasoline cuts of FCC obtained in step b) fluid catalytic cracking by sending all or part of the C4 cut obtained in step j) and all or part of the selectively hydrogenated light gasoline cut of FCC (LCN) obtained in step i) into a single-stage oligomerization and catalytic cracking unit. An example of a single-stage oligomerization and catalytic cracking process is the Olicrack™ process marketed by Axens.

In one embodiment, the process according to the invention further comprises a liquid-liquid extraction step h) comprising the treatment of a portion of the FCC gasoline cut obtained in step b) of fluid catalytic cracking, or in one embodiment of the hydrotreated heavy FCC gasoline cut (HCN) obtained in optional step i), in a liquid-liquid extraction unit, and obtaining an extract concentrated in aromatic compounds of 6 to 10 carbon atoms (C6-C10) and a raffinate concentrated in non-aromatic compounds and in aromatic compounds with 11 carbons and more (C11+).

“Concentrate in” means a content of at least 95% by weight, preferably at least 99% by weight, very preferably at least 99.5% by weight of desired compounds.

According to one embodiment, the liquid-liquid extraction unit comprises the following steps/devices:

- extraction using a liquid-liquid extractor fed with a solvent flow to separate the raffinate and the extract,

- washing the raffinate with water using a water washing tower,

- water stripping with a water stripping section,

- stripping of the extract with an extract stripping section,

- separation of aromatics with recovery tower to separate the extract and the solvent stream, and

- solvent regeneration with a solvent regeneration section.

According to one or more embodiments, the solvent comprises a compound selected from ethylene glycol, diethylene glycol, triethylene glycol, hexamethylphosphoramide, propylene carbonate, ethylene carbonate, sulfolane, 3-methylsulfolane, N-methylacetamide, N,N-dimethylacetamide, butyrolactone, 1-methylpyrrolidone, dimethylsulfoxide, caprolactam, N-methylformamide, pyrrolidin-2-one, furfural, 1,1,3,3-tetramethylurea and a mixture thereof. According to one embodiment, the solvent comprises or consists of sulfolane.

According to one embodiment, the solvent consists of at least 90% by weight, preferably at least 95% by weight (e.g. at least 99% by weight), sulfolane, relative to the total weight of the solvent. According to one embodiment, the solvent further comprises an anti-solvent, such as water. According to one embodiment, the solvent comprises between 0.01% by weight and 5% by weight, preferably between 0.1% by weight and 3% by weight (e.g. between 0.5% by weight and 2% by weight) of anti-solvent, such as water, relative to the total weight of the solvent.

According to one embodiment, the liquid-liquid extraction unit is operated at a pressure of between 0.05 and 3 MPa, preferably between 0.1 and 2 MPa, preferably between 0.2 and

1.5 MPa, preferably between 0.3 and 1 MPa, such as 0.65 ±0.2 MPa, for example when the solvent comprises sulfolane.

According to one embodiment, the liquid-liquid extraction unit is operated at a temperature between 10 and 150°C, preferably between 15 and 120°C, preferably between 20 and 100°C, preferably between 30 and 90°C, such as 54 ±5°C, for example when the solvent comprises sulfolane.

According to one embodiment, the solvent/filler ratio is between 2 and 10, preferably between 4 and 8.

Step i) naphtha hydrotreatment

In one embodiment, the process according to the invention further comprises a step i) of naphtha hydrotreatment comprising the treatment of all or part of a naphtha and/or FCC gasoline cut chosen from the cuts obtained in steps a) and b) alone or as a mixture in a hydrotreatment unit comprising a reactor containing a hydrotreatment catalyst, operated in the presence of hydrogen, at a temperature between 200°C and 400°C, preferably between 250°C and 370°C, under a pressure between 0.2 MPa and

2.5 MPa, preferably between 0.5 MPa and 2.0 MPa, and obtaining a hydrotreated naphtha cut and/or hydrotreated FCC gasoline.

Advantageously, step i) is carried out at an incoming load WH of between 1 h ^-1 and 10 h ¹ , preferably between 4 h ^-1 and 8 h ^-1 .

Advantageously, step i) is carried out at a hydrogen volume coverage relative to the incoming charge volume of between 100 and 350 Nm ³ /m ³ of liquid charge, preferably between 170 and 300 Nm ³ /m ³ .

The optional naphtha hydrotreatment step advantageously allows the removal of sulfur (hydrodesulfurization), and/or the removal of nitrogen (hydrodenitrogenation or hydrodenitration) which are poisons for the catalysts used in downstream units such as the catalytic reforming unit for example.

The operating conditions used in step i) advantageously make it possible to carry out hydrotreatment of the feedstock so as to achieve an organic nitrogen content in the effluent of less than 1 ppm by weight.

The operating conditions used in step i) advantageously make it possible to carry out hydrotreatment of the feedstock in such a way as to achieve a sulfur content in the effluent of less than 1 ppm by weight.

Advantageously, the hydrotreatment catalyst is chosen from among the conventional hydrotreatment catalysts known to those skilled in the art.

Preferably, the catalyst comprises a hydrogenating function composed of one or more metals from group VI B and one or more metals from group VI II B, taken alone or as a mixture, said catalyst being a catalyst having a sulfide phase as active phase.

The metal(s) of group VI B are advantageously chosen from chromium, molybdenum and tungsten, alone or as a mixture and preferably chosen from molybdenum and tungsten. Preferably, the content of metal of group VI B in the hydrotreatment catalyst(s) is advantageously between 5 and 40% by weight and preferably between 7 and 30% by weight, very preferably between 10 and 28% by weight, the percentages being expressed as percentage by weight of oxides.

The metal(s) from group VIII are advantageously chosen from iron, cobalt, nickel, ruthenium, rhodium, palladium and platinum, and preferably from cobalt or nickel. Preferably, the content of metal from group VIII in the hydrotreatment catalyst(s) is advantageously between 0.5 and 15% by weight and preferably between 1.5 and 10% by weight, the percentages being expressed as percentage by weight of oxides.

The hydrotreatment catalyst may also advantageously comprise at least one promoter element deposited on said catalyst chosen from the group formed by phosphorus, boron and silicon, optionally one or more elements from group VI IA (chlorine and fluorine preferred), optionally one or more elements from group VII B (manganese preferred), and optionally one or more elements from group VB (niobium preferred). The concentration of said promoter is advantageously less than 20% by weight, and preferably less than 10% by weight relative to the weight of the catalyst.

Advantageously, the catalyst may further contain one or more adjuvant additives leading to better dispersion and promotion of the active phase of the catalyst, so as to improve its activity. Said additives are typically one or more compounds organic compounds containing oxygen and/or one or more organic compounds containing nitrogen and/or one or more organic compounds containing sulfur. When present, the total content of organic compound(s) containing oxygen and/or nitrogen and/or sulfur present in the catalyst is generally between 1 and 30% by weight, preferably between 1.5 and 25% by weight, and more preferably between 2 and 20% by weight relative to the total weight of the catalyst.

Preferably, the hydrotreatment catalyst is supported on a support chosen from alumina, silica alumina, and preferably on alumina.

In one embodiment, in step i) of naphtha hydrotreatment, when the optional step k) of residue hydrotreatment is implemented, the naphtha cut can also be chosen in step k).

In one embodiment, in step i) of naphtha hydrotreatment, the naphtha cuts are treated jointly or separately in the same hydrotreatment section, or separately in separate sections.

Advantageously, step i) of naphtha hydrotreatment comprises the treatment of all or part of the naphtha cuts resulting from steps a) of atmospheric distillation and optionally k) of residue hydrotreatment in a first hydrotreatment section i-

51), and the treatment of all or part of the FCC gasoline cut obtained in step b) of fluid catalytic cracking in a second hydrotreatment section i-S2). This configuration makes it possible to separately treat the FCC gasoline comprising aromatics which can be recovered in step h) of liquid-liquid extraction without diluting them with a naphtha cut comprising few aromatics.

In a preferred embodiment, the treatment of all or part of the naphtha cuts from steps a) of atmospheric distillation and optionally k) of residue hydrotreatment in the first hydrotreatment section i-S1) is followed by a step of separation of the hydrotreated naphtha cut to obtain a hydrotreated light naphtha cut and/or a hydrotreated heavy naphtha cut.

In a preferred embodiment, the treatment of all or part of the FCC gasoline cut obtained in step b) of fluid catalytic cracking in the hydrotreatment section i-

52) comprises a step of selective hydrogenation of diolefins to olefins followed by a separation step to obtain a selectively hydrogenated light gasoline cut of FCC (LCN) essentially comprising olefins and a heavy gasoline cut of FCC (HCN). The HCN cut can then advantageously undergo a step of hydrogenation of olefins to paraffins and removal of sulfur (hydrodesulfurization) and/or removal of nitrogen (hydrodenitration or hydrodenitration) followed by a separation step to obtain a hydrotreated light FCC (LCN) gasoline cut and/or a hydrotreated heavy FCC (HCN) gasoline cut. In this embodiment, the hydrotreated FCC gasoline cut is therefore either the selectively hydrogenated LCN cut, or the hydrotreated LCN cut, or the hydrotreated HCN cut.

In one embodiment, in step i) of hydrotreatment, a gas cut is further obtained. Advantageously, an LPG cut can be separated from the gas cut.

Step j) of propylene recovery

In one embodiment, the method further comprises a step j) of propylene recovery comprising the treatment of all or part of the LPG cut obtained in step b) of fluid catalytic cracking in a propylene recovery unit, and obtaining a C4 cut, a propane cut and a propylene cut at polymer grade, i.e. comprising more than 99.5% by weight of propylene.

The propylene recovery unit allows the separation of the different components according to their relative volatility. A first column, the depropanizer, allows the recovery of a C4 cut at the bottom of the column, and at the top of the column a stream comprising mainly propane and propylene. This stream is then sent to a second column, the deethanizer. The stream at the top of the deethanizer (C2- cut), can be returned either to the fluid catalytic cracking step b) or to the ethylene recovery step m) depending on the composition of this stream. The bottom of the deethanizer column is sent to a third column, the C3 separator, where the propane/propylene separation takes place. The separations advantageously take place under a pressure between 0.1 and 25 MPa and at a high temperature between 100 and 150°C.

Advantageously, the incoming feed from the second column is treated in a caustic wash to remove certain contaminants, such as carbonyl sulfide.

Step k) of residue hydrotreatment

In one embodiment, the process according to the invention further comprises a step k) of residue hydrotreatment comprising the treatment of all or part of the atmospheric residue cut obtained in step a) in a hydrotreatment unit comprising a reactor containing a hydrotreatment catalyst, operated in the presence of hydrogen, at a temperature of between 300°C and 500°C, preferably between 350°C and 430°C, under a pressure of between 5 MPa and 35 MPa, preferably between 11 MPa and 26 MPa, and obtaining a hydrotreated atmospheric residue cut.

Advantageously, step k) is carried out at an incoming load WH of between 0.1 tr ¹ and 5 h' ¹ , preferably between 0.1 h' ¹ and 3 h' ¹ . Advantageously, step k) is carried out at a volume coverage of hydrogen relative to the volume of the charge of between 100 and 5000 Nm ³ /m ³ , preferably between 200 and 2000 Nm ³ /m ³ .

The optional step of hydrotreatment of all or part of the atmospheric residue cut is advantageously carried out in one or more reactors, preferably fixed bed reactors arranged in series, and advantageously allows in the first reactor(s) the elimination of metals (hydrodemetallization: HDM) as well as part of the elimination of sulfur (hydrodesulfurization: HDS), a so-called HDM step, and in the last reactor(s) the deep refining of the feedstock, in particular hydrodesulfurization, a so-called HDS step. The effluents are withdrawn from the last HDS reactor.

This step advantageously makes it possible to avoid poisoning the catalysts used in the downstream units, in particular in step b) of fluid catalytic cracking.

The HDM step is preferably implemented when the feed contains more than 50 ppm, or even more than 100 ppm of metals and/or when the feed includes impurities likely to cause excessively rapid clogging of the catalytic bed, such as iron or calcium derivatives for example. The aim is to reduce the impurity content and thus protect the downstream HDS step from deactivation and clogging. It can be implemented in switchable reactors.

In one embodiment, the hydrotreating catalyst comprises an HDM catalyst and/or an HDS catalyst.

For the HDM stage, the ideal catalyst must be able to treat feedstocks that may be rich in asphaltenes, while having a high demetallizing power associated with a high metal retention capacity and high resistance to coking. The HDM catalyst advantageously has the following characteristics:

- Demetallization rate of at least 10% to 90% in the HDM stage;

- Metal retention capacity greater than 10% relative to the weight of new catalyst, which allows for longer operating cycles;

- High resistance to coking even at temperatures above 390°C, which contributes to extending the duration of cycles often limited by the increase in pressure drop and loss of activity due to coke production, and which allows the majority of thermal conversion to be carried out in this stage.

For the HDS stage, the ideal catalyst must have a strong hydrogenating power in order to achieve deep refining of the products: desulfurization, continued demetallization, lowering of Conradson carbon and possibly of the asphaltene content. The HDM and HDS catalysts may be any catalysts known to those skilled in the art for carrying out HDM and HDS steps. They may be granular catalysts comprising, on a support, at least one metal or metal compound having a hydro/dehydrogenating function. These catalysts may advantageously be catalysts comprising a metal from group VIII, generally chosen from the group consisting of nickel and cobalt, and/or a metal from group VI B, preferably molybdenum and/or tungsten. 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) relative to the total weight of the catalyst, on a mineral support may be used. The mineral support may, for example, be chosen from the group consisting of alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. Advantageously, the mineral support may contain 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. An alumina support is most often used, and very often an alumina support doped with phosphorus and possibly boron. When phosphoric anhydride P2O5 is present, its concentration is less than 10% by weight relative to the weight of the support. When boron trioxide B2O5 is present, its concentration is less than 10% by weight relative to the weight of the support. The alumina used may be a y (gamma) or q (eta) alumina. The catalysts are most often in the form of extrudates. The total content of metal oxides from groups VI B and VIII may be from 3% to 40% by weight, preferably from 5% to 30% by weight relative to the total weight of catalyst, and the weight ratio, expressed as metal oxide, between metal (or metals) from group VIB and metal (or metals) from group VIII is generally between 20 and 1, and most often between 10 and 2.

Catalysts usable in the HDM step are for example described in documents EP0113297, EP0113284, US5221656, US5827421, US7119045, US5622616 and US 5089463.

Catalysts usable in the HDS step are for example described in patent documents EP0113297, EP0113284, US6589908, US4818743 or US6332976.

An example of an atmospheric residue hydrotreatment process is the Hyvahl™ process marketed by Axens.

In one embodiment, in step k) of residue hydrotreatment, a gas cut is further obtained. Advantageously, an LPG cut can be separated from the gas cut.

In one embodiment, in step k) of residue hydrotreatment, a naphtha cut is further obtained. In one embodiment, in step k) of residue hydrotreatment, a diesel cut is further obtained.

Step I) hydrotreatment of LCO

In one embodiment, the process according to the invention further comprises a step I) of hydrotreatment of LCO comprising the treatment of all or part of the LCO cut obtained in step b) of fluid catalytic cracking, in a hydrotreatment unit comprising a reactor containing a hydrotreatment catalyst, operated in the presence of hydrogen, at a temperature between 340°C and 420°C, under a pressure between 3 MPa and 12 MPa, and obtaining a hydrotreated LCO cut.

Advantageously, step I) is carried out at an incoming load WH of between 0.5 h' ¹ and 4 h' ¹ .

Advantageously, step I) is carried out at a hydrogen volume coverage relative to the incoming charge volume of between 100 and 1800 Nm ³ / m ³ of liquid charge.

The optional hydrotreatment step I) advantageously allows the hydrogenation of aromatics (in order to possibly allow the cracking of the hydrotreated LCO cut in step b) of fluid catalytic cracking), as well as the elimination of sulfur (hydrodesulfurization), and/or the elimination of nitrogen (hydrodenitrogenation or hydrodenitration).

The hydrotreatment catalyst is advantageously chosen from among the conventional hydrotreatment catalysts known to those skilled in the art. It generally comprises a porous mineral support, one or more metals or compounds of metals from group VIII (this group including in particular cobalt, nickel, iron, etc.) and one or more metals or compounds of metals VI B (this group including in particular molybdenum, tungsten, etc.).

The sum of the metal(s) or metal compound(s), expressed as weight of metal relative to the total weight of the catalyst, is advantageously between 0.5 and 50% by weight. The sum of the metal(s) or metal compound(s) from group VIII, expressed as weight of metal relative to the weight of the catalyst, is advantageously between 0.5 and 15% by weight, preferably between 1 and 10% by weight. The sum of the metal(s) or metal compound(s) from group VI B, expressed as weight of metal relative to the weight of the catalyst, is advantageously between 2 and 50% by weight, preferably between 5 and 40% by weight.

The porous mineral support may comprise, but is not limited to, one of the following compounds: alumina, silica, zirconia, titanium oxide, magnesia, or two compounds selected from the preceding compounds, for example silica-alumina or alumina-zirconia, or alumina-titanium oxide, or alumina-magnesia, or three or more compounds selected from the preceding compounds, for example silica-alumina-zirconia or silica-alumina-magnesia. The support may also comprise, in part or in whole, a zeolite. Preferably the catalyst comprises a support composed of alumina, or a support composed mainly of alumina (for example from 80 to 99.99% by weight of alumina). The porous support may also comprise one or more other promoter elements or compounds, based for example on phosphorus, magnesium, boron, silicon, or comprising a halogen. The support may for example comprise a content of 0.01 to 20% by weight of B2O3, or of SiC>2, or of P2O5, or of a halogen (for example chlorine or fluorine), or a content of 0.01 to 20% by weight of a combination of several of these promoters. Common catalysts are, for example, catalysts based on cobalt and molybdenum, or nickel and molybdenum, or nickel and tungsten, on an alumina support, this support being able to comprise one or more promoters as previously mentioned.

In one embodiment, in step I) of LCO hydrotreatment, a gas cut is further obtained. Advantageously, an LPG cut can be separated from the gas cut.

In one embodiment, in step I) of LCO hydrotreatment, a naphtha cut is further obtained.

Step m) of recovery and purification of ethylene

In one embodiment, the method further comprises a step m) of recovery and purification of ethylene comprising the treatment of all or part of the cut essentially comprising C1 and C2 hydrocarbon compounds (C1-C2 cut) from step b) of fluid catalytic cracking in an ethylene recovery unit (Ethylene Recovery Unit or ERU according to English terminology), and obtaining a cut comprising dihydrogen, methane and nitrogen, and an ethylene cut at polymer grade, i.e. comprising more than 99.5% by weight of ethylene.

Advantageously, before sending all or part of the C1-C2 cut to distillation columns allowing the compounds to be separated according to their relative volatility, it passes through a purification train in order to remove a significant number of impurities, including oxygenates (Nox and O2), dienes, acetylene but also sulfur and sulfur compounds, water, arsenic and mercury.

This purification of the C1-C2 cut allows, among other things, to meet the specifications on these compounds at the input of the separation part of this stage, due to the need for a cold box for optimal operation of the distillation columns.

The C1-C2 cut is sent to a cold box allowing at least two outputs to be obtained: a cut, comprising a mixture of C1 and H2, and a cut comprising C1 and C2 compounds sent to a demethanizer. This allows at least two cuts to be obtained: a methane cut at the top and a C2 cut comprising ethane and ethylene at the bottom of the column. The C2 cut is then sent to a C2 separator, allowing the production of a polymer grade ethylene cut at the top of the column and an ethane cut at the bottom of the column, combined with the cut comprising a mixture of C1 and H2 at the top of the cold box.

Concerning the purification part, the operating conditions are advantageously the following: temperature between 30°C and 300°C, and preferably between 40°C and 260°C; pressure between 0.1 and 5 MPa, preferably between 0.5 and 3 MPa and more preferably between 1 and 2 MPa,

Concerning the fractionation part, the operating conditions are advantageously the following: temperature between -120°C and 100°C, and preferably between - 100°C and 50°C; pressure between 0.1 and 5 MPa, preferably between 0.5 and 3.5 MPa. It should be noted that the operating conditions are specifically defined for each of the separation stages described above.

In one embodiment, the cut comprising a mixture of C1 and H2 and/or the ethane cut, obtained in step m) is sent to step d) of steam cracking.

DESCRIPTION OF FIGURES

Figure 1: A crude oil feedstock 1 is sent to an atmospheric distillation step a) to obtain a naphtha cut 3, a diesel cut 4 and an atmospheric residue cut 5. Cut 5 is sent to a fluid catalytic cracking step b) to obtain an LPG cut 46, an FCC gasoline cut 11 and an LCO cut 12. Cuts 4 and 12 are sent to a hydrocracking step c) to obtain a light naphtha cut 15, and a heavy naphtha cut 16. Cut 11 is sent to a one-step oligomerization and catalytic cracking step g) to obtain a cut comprising essentially propylene and ethylene 51. Cuts 3, 15, 51 and possibly a part of cut 16 are sent to a steam cracking step d) to obtain an olefinic cut (40 ethylene, or 41 propylene, or 42 butadiene). Part or all of the cut 16 is sent to a catalytic reforming step e) to obtain a reformate cut 32. The cut 32 is sent to a step f) of transformation and/or separation of the aromatics to obtain an aromatic cut (36 benzene, or 37 paraxylene).

Figure 2: A crude oil feedstock 1 is sent to an atmospheric distillation step a) to obtain a gas cut 2, a naphtha cut 3, a diesel cut 4 and an atmospheric residue cut 5. Cut 5 is sent to a residue hydrotreatment step k) to obtain a gas cut 6, a naphtha cut 7, a diesel cut 8 and a hydrotreated atmospheric residue cut 9. Cut 9 is sent to a fluid catalytic cracking step b) to obtain a cut comprising essentially C1 and C2 hydrocarbon compounds 10, an LPG cut 46, an FCC gasoline cut 11, an LCO cut 12 and a heavy oil cut 13. The LPG cut 46 is sent to a step j) of propylene recovery to obtain a propane cut 50, a propylene cut 49 and a C4 cut 48. At least a portion of cut 4 is sent to a first hydrocracking section c-S1) to obtain a gas cut 14, a light naphtha cut 15, a heavy naphtha cut 16 and a purge cut 17. At least a portion of cut 4, cut 8 and cut 12 are sent to a second hydrocracking section c-S2) to obtain a gas cut 23, a light naphtha cut 24, a heavy naphtha cut 25 and a purge cut 26. Cuts 3 and 7 are sent to a first naphtha hydrotreatment section i-S1) to obtain a gas cut 27, a hydrotreated light naphtha cut 28 and a hydrotreated heavy naphtha cut 29. Cut 11 is sent to a second hydrocracking section i-S2) of naphtha hydrotreatment to obtain a selectively hydrogenated LCN cut 47, a hydrotreated LCN cut 19, a gas cut 18, and a hydrotreated HCN cut 20. Cut 20 is sent to a liquid-liquid extraction step h) to obtain an extract concentrated in aromatic compounds of 6 to 10 carbon atoms (C6-C10) 21 and a raffinate concentrated in non-aromatic compounds and in aromatic compounds with 11 carbons and more (C11 +) 22. Cuts 47 and 48 are sent to a step g) of oligomerization and catalytic cracking in one step to obtain a cut essentially comprising propylene and ethylene 51, a cut essentially comprising hydrocarbon compounds having from 4 to 6 carbon atoms (C4-C6) 52 and a cut essentially comprising hydrocarbon compounds having 7 carbon atoms and plus (C7+) 53. Part of cut 52 is recycled as input to step g). Cuts 16, 22, 25, 29 and 53 are sent to a catalytic reforming step e) to obtain a hydrogen cut 30, a gas cut 31, and a reformate cut 32. Cuts 2, 6, 10, 14, 18, 23, 27, 31, 50, 51, 15, 24, 28, 19 and the other part of cut 52 are sent to a steam cracking step d) to obtain a cut 39 comprising H ₂ , H ₂ S, CO and CH ₄ , an olefinic cut (40 ethylene, or 41 propylene, or 42 butadiene), a light pyrolysis gasoline cut 43, a heavy pyrolysis gasoline cut 44 and a pyrolysis oil cut 45. Cut 44 is sent to the first section hydrocracking c-S1). Cuts 21, 32 and 43 are sent to a stage f) of transformation and/or separation of aromatics to obtain an ethane cut 33, an LPG cut 34, a raffinate cut 35, an aromatic cut (36 benzene, or 37 paraxylene), and a heavy aromatic cut 38. Cuts 33, 34 and 35 are sent to stage d) of steam cracking.

Figure 3: The diagram of Figure 3 is identical to that of Figure 3, except that in step d) of steam cracking a C4 54 cut is additionally obtained which is sent to step g) of oligomerization and catalytic cracking in one step.

EXAMPLES

1: Method according to the embodiment of figure 2: The example below illustrates a particular implementation of the method according to the invention without limiting its scope.

The heavy hydrocarbon feedstock 1 treated in the process is a crude oil from the Middle East and having the properties indicated in the table below.

Table 1

The feed is subjected to a step a) of atmospheric distillation, the cuts obtained are described in the table below.

Table 2

The atmospheric residue cut 5 is sent to step k) of residue hydrotreatment in five fixed bed reactors in series and in the presence of different hydrotreatment catalysts (hydrodemetallation catalyst, transition catalyst and hydrodesulfurization catalyst) in fixed bed of CoMoNi type on Alumina under the conditions indicated in the table below.

Table 3

A hydrotreated atmospheric residue cut 9 obtained in step k) of residue hydrotreatment is sent to a step b) of fluid catalytic cracking in the presence of a zeolitic catalyst on alumina under the conditions indicated in the table below. Table 4

Part of the diesel cut 4 from atmospheric distillation a) and the pyrolysis gasoline cut 44 from steam cracking step d) are sent to fixed bed hydrocracking step c) in a first section c-S1) carried out under the conditions presented in the following table.

Table 5

The fractionation part of step c-S1) separates the light naphtha cut and the heavy naphtha cut considering a cutting point at 65°C.

At the end of steps a), k) and b), the diesel and LCO cuts 4, 8 and 12 respectively obtained are sent, partly for cut 4, and entirely for cuts 8 and 12, to a fixed bed hydrocracking step c) in a second section c-S2) carried out under the conditions presented in the following table. Table 6

The fractionation part of step c-S2) separates the light naphtha cut and the heavy naphtha cut considering a cutting point at 65°C.

The naphtha cut 3 from atmospheric distillation step a) and a naphtha cut 7 from residue hydrotreatment step k) are sent to a first fixed-bed hydrotreatment section i-S1) under the conditions indicated in the following table.

Table 7

The fractionation part of step i-S1) separates the hydrotreated light naphtha cut and the hydrotreated heavy naphtha cut considering a cutting point at 65°C.

The FCC 11 gasoline cut from fluid catalytic cracking step b) is sent to a second fixed-bed hydrotreatment section i-S2) consisting of a first reactor for selective hydrogenation of diolefins and then a second reactor for hydrogenation of olefins, the conditions of which are indicated in the table below. Table 8

The fractionation part of step i-S2) separates the hydrotreated LCN cut and the hydrotreated HCN cut considering a cutting point at 65°C.

The GPL 46 cut obtained in step b) of fluid catalytic cracking is sent to a step j) of propylene recovery.

The selectively hydrogenated LCN cut 47 and the C4 cut 48 obtained respectively in steps i-S2) and j) are sent to a step g) of oligomerization and catalytic cracking in one step under the conditions indicated in the table below.

Table 9

The recycle flow rate of the cut comprising essentially hydrocarbon compounds having 4 to 6 carbon atoms (C4-C6) 52 from the single-stage oligomerization and catalytic cracking unit g), relative to the flow rate of the feedstock entering said unit, is 2. The hydrotreated HCN cut 20 from the unit i-S2) is sent to a liquid-liquid extraction step h) of the C6-C10 aromatic compounds, the conditions of which are indicated in the table below.

Table 10

The heavy naphtha cuts 16, 25, 29 and the raffinate cut concentrated in non-aromatic compounds and in C11+ 22 resulting respectively from the hydrocracking stages c) in sections c-S1) and c-S2), i-S1) of hydrotreatment and h) of liquid-liquid extraction are sent to a stage e) of catalytic reforming, and treated under the conditions set out in the following table.

Table 11

WAIT = weighted-average inlet temperature according to Anglo-Saxon terminology or weighted average temperature at the entrance to the reforming stage.

The concentrated extract of C6-C10 aromatic compounds 21 from the liquid-liquid extraction step h), the reformate cut 32 from the catalytic reforming step e) and the light pyrolysis gasoline cut 43 from the steam cracking step d) are sent to the aromatics transformation and/or separation step f).

The light naphtha cuts 15, 24, 28, the hydrotreated LCN cut 19 and at least a portion of the cut 52 originating respectively from the stages c) of fixed bed hydrocracking in sections c-S1) and c-S2), hydrotreatment i-S1) and i-S2) and oligomerization and one-stage catalytic cracking g), the gas cuts 2, 6, 14, 23, 18, 27, 31, the cut essentially comprising C1 and C2 hydrocarbon compounds 10, the propane cut 50 and the cut essentially comprising propylene and ethylene 51, originating respectively from the stages a) of atmospheric distillation, k) of residue hydrotreatment, b) of fluid catalytic cracking, hydrocracking in sections c-S1) and c-S2) and hydrotreatment in sections i-S1) and i-S2), catalytic reforming e), fluid catalytic cracking b) propylene recovery j) and oligomerization and one-step catalytic cracking g), and a cut ethane 33, an LPG cut 34 and a paraffin-rich raffinate cut 35 from step f) of transformation and/or separation of aromatics are sent to a steam cracking step d) where each of the cuts is cracked under different conditions set out in the following table. Table 12

The entirety of the pyrolysis oil cut 45 obtained in step d) of steam cracking, part of the diesel cut 4 from atmospheric distillation a), the heavy oil cut 13 from step b) of fluid catalytic cracking, and the purge cuts 17 and 26 from the hydrocracking units c-S1) and c-S2) are used for the production of a low-sulfur fuel oil.

The following table shows the product yields from the different stages of the process according to example 1.

Table 13

When the total is greater than 100% for a step, this means that a secondary charge has been injected into said step, such as, for example, hydrogen in steps k) and c).

The following table shows different yields in percentage by weight relative to the weight of the crude oil feedstock entering the process.

Tablet 4

Compared to the crude oil feedstock introduced in atmospheric distillation step a), the process according to Example 1 achieves total mass yields of 77.2% of 10 petrochemical base products. The olefin yields are: 18.3% ethylene, 21.6% propylene and 1.5% butadiene. The aromatic yields are 0.3% benzene and 26.9% paraxylene. In addition, the specific sequence of steps upstream of the steam cracking step limits coke formation.

Example 2: Method according to the embodiment of figure 3 with sending of the C4 15 cut obtained in step d) to step g) as co-load:

The example below illustrates a particular implementation of the method according to the invention without limiting its scope.

Example 2 differs from Example 1 by obtaining an O4 cut in step d) of steam cracking which is sent as a co-charge to the oligomerization and catalytic cracking step 20 in one step g).

Thus, in this example, the charge of step g) is composed of cuts 47, 48 and 54. The operating conditions of step g) are unchanged compared to the conditions presented in Table 9 of example 1.

25 The following table shows the product yields from the different stages of the process according to example 2.

Table 15

The following table shows the different yields in percentage by weight relative to the weight of the crude oil feedstock entering the process.

Table 16

Compared to the crude oil feedstock introduced in step a) of atmospheric distillation, the process according to Example 2 makes it possible to achieve total mass yields of 78.4% of basic products for petrochemicals. The olefin yields are: 17.7% ethylene, 22.5% propylene and 1.4% butadiene. The aromatic yields are 9.2% benzene and 27.6% paraxylene. The process according to Example 2 makes it possible to significantly increase the conversion of the feedstock into petrochemical products (+1.2%), which is reflected in particular by an increase in the production of propylene (+0.9%) and paraxylene (+0.7%) compared to Example 1, and therefore to direct the conversion towards the production of propylene.

Claims

1. A process for producing olefins and aromatics from a hydrocarbon feedstock comprising crude oil, the process comprising the following steps: a) an atmospheric distillation step comprising treating all or part of the hydrocarbon feedstock comprising crude oil in an atmospheric distillation unit, and obtaining a naphtha cut, a diesel cut and an atmospheric residue cut; b) a fluid catalytic cracking step comprising treating all or part of the atmospheric residue cut obtained in step a) in an FCC unit comprising a catalytic cracking zone operating in an upflow or downflow mode containing an FCC catalyst, operating at a temperature at the outlet of the catalytic cracking zone of between 400 and 700°C, at a pressure in the catalytic cracking zone of between 0.1 and 2 MPa, and obtaining an LPG cut, an FCC gasoline cut and a light distillate cut; c) a fixed-bed hydrocracking step comprising the treatment of all or part of a diesel and/or light distillate cut selected from the cuts obtained in steps a) and b) alone or as a mixture in a hydrocracking unit comprising a reactor containing a hydrocracking catalyst, operated in the presence of hydrogen, at a temperature of between 250 and 480°C, under a pressure of between 2 and 25 MPa, and obtaining a light naphtha cut and a heavy naphtha cut; d) a steam cracking step comprising the treatment of all or part of the naphtha and/or light naphtha and/or heavy naphtha cuts and/or cut essentially comprising propylene and ethylene selected from the cuts obtained in steps a), c) and g) alone or as a mixture in a steam cracking unit comprising a pyrolysis furnace, and obtaining an olefinic cut; e) a catalytic reforming step comprising the treatment of all or part of the heavy naphtha cut obtained in step c) in a catalytic reforming unit comprising a reactor containing a reforming catalyst, operated under a pressure of between 0.1 and 25 MPa and at a temperature of between 480 and 570°C, and obtaining a reformate cut; f) a step of transformation and/or separation of aromatics comprising the treatment of all or part of the reformate cut obtained in step e) in a unit for transformation and/or separation of aromatics, and obtaining an aromatic cut; g) a one-stage oligomerization and catalytic cracking step, comprising the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking in a one-stage oligomerization and catalytic cracking unit comprising a reactor containing a catalyst allowing the oligomerization and catalytic cracking of olefins, operated at a temperature of between 400 and 600°C, and at a pressure of between 0.1 and 1 MPa, and obtaining a cut essentially comprising propylene and ethylene. 2. Process according to claim 1 in which, in step d) of steam cracking, a heavy pyrolysis gasoline cut is also obtained. 3. Process according to any one of the preceding claims, further comprising a step k) of residue hydrotreatment comprising the treatment of all or part of the atmospheric residue cut obtained in step a) in a hydrotreatment unit comprising a reactor containing a hydrotreatment catalyst, operated in the presence of hydrogen, at a temperature between 300°C and 500°C, under a pressure between 5 MPa and 35 MPa, and obtaining a hydrotreated atmospheric residue cut. 4. Process according to claim 3 in which, in step k) of hydrotreatment, a diesel cut is also obtained. 5. Process according to claim 4 in which, step c) of hydrocracking comprises the treatment of all or part of the heavy pyrolysis gasoline cut resulting from step d) of steam cracking and/or of a first part of the diesel cut resulting from step a) of atmospheric distillation in a first hydrocracking section c-S1), and the treatment of all or part of the light distillate cut obtained in step b) of fluid catalytic cracking and/or all or part of the diesel cut obtained in the optional step k) of residue hydrotreatment and/or of a second part of the diesel cut resulting from step a) of atmospheric distillation in a second hydrocracking section c-S2). 6. Process according to any one of the preceding claims, further comprising a step i) of hydrotreatment of naphtha comprising the treatment of all or part of a naphtha and/or FCC gasoline cut chosen from the cuts obtained in steps a) and b) alone or as a mixture in a hydrotreatment unit comprising a reactor containing a hydrotreatment catalyst, operated in the presence of hydrogen, at a temperature between 200°C and 400°C, under a pressure between 0.2 MPa and 2.5 MPa, preferably between 0.5 MPa and 2.0 MPa, and obtaining a hydrotreated naphtha and/or hydrotreated FCC gasoline cut. 7. Process according to any one of claims 3 to 6 in which, in step k) of residue hydrotreatment, a naphtha cut is also obtained. 8. Process according to claim 7 in which step i) of naphtha hydrotreatment comprises the treatment of all or part of the naphtha cuts from steps a) of atmospheric distillation and k) of residue hydrotreatment in a first hydrotreatment section i-S1), and the treatment of all or part of the FCC gasoline cut obtained in step b) of fluid catalytic cracking in a second hydrotreatment section i-S2). 9. Process according to claim 8 in which the treatment of all or part of the naphtha cuts resulting from steps a) of atmospheric distillation and k) of residue hydrotreatment in the first hydrotreatment section i-S1) is followed by a step of separation of the hydrotreated naphtha cut to obtain a hydrotreated light naphtha cut and/or a hydrotreated heavy naphtha cut. 10. Process according to claim 8 or 9 in which the treatment of all or part of the FCC gasoline cut obtained in step b) of fluid catalytic cracking in the hydrotreatment section i-S2) comprises a step of selective hydrogenation of the diolefins into olefins followed by a separation step to obtain a selectively hydrogenated light FCC gasoline cut essentially comprising olefins and a heavy FCC gasoline cut. 11. Process according to any one of the preceding claims, further comprising a step j) of propylene recovery comprising the treatment of all or part of the LPG cut obtained in step b) of fluid catalytic cracking in a propylene recovery unit, and obtaining a C4 cut, a propane cut and a polymer grade propylene cut. 12. Process according to claim 11, in which step g) of oligomerization and one-step catalytic cracking comprises the treatment of the olefins contained in the LPG and FCC gasoline cuts obtained in step b) of fluid catalytic cracking by sending all or part of the C4 cut obtained in step j) and all or part of the selectively hydrogenated light FCC gasoline cut obtained in step i) into a one-step oligomerization and catalytic cracking unit. 13. Process according to any one of claims 10 to 12 in which the heavy FCC gasoline cut undergoes a step of hydrogenation of the olefins into paraffins and removal of sulfur and/or removal of nitrogen followed by a separation step to obtain a hydrotreated light FCC gasoline cut and/or a hydrotreated heavy FCC gasoline cut. 14. Process according to any one of claims 9 to 13 in which step d) of steam cracking further comprises the treatment of all or part of the hydrotreated light naphtha cut and/or hydrotreated heavy naphtha and/or hydrotreated light FCC gasoline obtained in step i) of naphtha hydrotreatment. 15. Process according to any one of claims 13 or 14, further comprising a step h) of liquid-liquid extraction comprising the treatment of all or part of the hydrotreated heavy FCC gasoline cut obtained in step i) of naphtha hydrotreatment, in a liquid-liquid extraction unit, and obtaining an extract concentrated in aromatic compounds of 6 to 10 carbon atoms and a raffinate concentrated in non-aromatic compounds and in aromatics with 11 carbons and more. 16. Process according to claim 15 in which step e) of catalytic reforming further comprises the treatment of all or part of the raffinate concentrated in non-aromatic compounds and in aromatic compounds with 11 carbons or more obtained in step h) of liquid-liquid extraction. 17. Process according to any one of claims 15 or 16 in which step f) of transformation and/or separation of the aromatics further comprises a treatment of all or part of the extract concentrated in aromatic compounds of 6 to 10 carbon atoms obtained in step h) of liquid-liquid extraction.