EP3728518A1

EP3728518A1 - Method for converting heavy hydrocarbon feedstocks with recycling of a deasphalted oil

Info

Publication number: EP3728518A1
Application number: EP18814904.1A
Authority: EP
Inventors: Joao MARQUES; Jan Verstraete
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2017-12-21
Filing date: 2018-12-07
Publication date: 2020-10-28
Anticipated expiration: 2038-12-07
Also published as: CN111819268A; ES2923131T3; WO2019121073A1; PT3728518T; SA520412257B1; CN111819268B; RU2020123948A; US11149217B2; FR3075809B1; FR3075809A1; PL3728518T3; EP3728518B1; RU2020123948A3; US20200339894A1

Abstract

The invention concerns a method for converting a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling temperature of at least 300°C and containing sulfur, Conradson carbon, metals and nitrogen, comprising at least two successive hydroconversion steps, that may be separated by an intermediate separation step, and at least one step of deasphalting a heavy fraction of the effluent from the hydroconversion, at least part of the deasphalted oil (DAO) being recycled during the hydroconversion, downstream from the first hydroconversion step. The DAO is either recycled upon exiting the deasphalter, or after having undergone a fractionation step producing a heavy fraction of the DAO that then constitutes the recycled part of the DAO. This method helps simultaneously improve the level of conversion and the stability of the liquid effluents.

Description

PROCESS FOR CONVERTING HEAVY HYDROCARBON LOADS

WITH RECYCLE OF A DESASPHALTEE OIL

Field of the invention

The present invention relates to the refining and conversion of heavy hydrocarbon feedstocks either from a crude oil or from the distillation of a crude oil, said feeds comprising a fraction of at least 50% having a boiling point. at least 300 ° C, and containing, inter alia, asphaltenes, sulfur, nitrogen impurities and metals. It is sought for the conversion of these charges into lighter products, recoverable as fuels, for example to produce gasoline or gas oils, or raw materials for petrochemicals.

In particular, the invention relates to a process for converting such a heavy load comprising hydroconversion steps in a three-phase reactor operating as a bubbling bed and deasphalting a fraction of the product resulting from hydroconversion, in which the oil deasphalted, called DAO for DeAsphalted Oil in English, resulting from the deasphalting is recycled during the hydroconversion.

General context

The fillers that it is desired to treat in the context of the present invention are either crude oils or heavy fractions of hydrocarbons derived from the distillation of a crude oil, also known as petroleum residues, and contain a fraction of at least 50% having a boiling point of at least 300 ° C, preferably at least 350 ° C and preferably at least 375 ° C. It is preferably vacuum residues containing a fraction of at least 50% having a boiling point of at least 450 ° C, and preferably at least 500 ° C.

These fillers generally have a sulfur content of at least 0.1%, sometimes at least 1% and even at least 2% by weight, a Conradson carbon content of at least 0.5% by weight and preferably at least 5% by weight, a C ₇ asphaltene content of at least 1% by weight and preferably at least 3% by weight and a metal content of at least 20 ppm by weight and preferably of at least 100 ppm by weight.

The valuation of these heavy loads is relatively difficult, both from a technical and an economic point of view. Indeed, the market is primarily requesting fuels that can be distilled at atmospheric pressure at a temperature below 380 ° C or 320 ° C. As regards crude oils, their atmospheric distillation leads to variable levels of atmospheric residues which depend on the origin of the crude oils treated. This content generally varies between 20% and 50% for conventional crude oils, but can reach 50% to 80% for heavy and extra heavy crude oils such as those produced in Venezuela or the Athabasca region in the United States. northern Canada. It is therefore necessary to convert these residues, transforming the heavy residue molecules to produce refined products made up of lighter molecules. These refined products generally have a much higher hydrogen to carbon ratio than the heavy cuts at the start. A series of processes used to produce refined light cuts, such as hydrocracking, hydrotreatment and hydroconversion processes, is therefore based on adding hydrogen to the molecules, preferably at the same time as cracking. these heavy molecules.

The conversion of heavy loads depends on a large number of parameters such as the composition of the feedstock, the reactor technology used, the severity of the operating conditions (temperature, pressure, hydrogen partial pressure, residence time, etc.). , the type of catalyst used and its activity. By increasing the severity of the operation, the conversion of heavy loads to light products is increased, but by-products, such as coke precursors and sediments, begin to be significantly formed via side reactions. The high conversion of heavy charges therefore very often results in the formation of solid, highly viscous and / or sticky particles composed of asphaltenes, coke and / or fine particles of catalyst. The excessive presence of these products leads to the coking and deactivation of the catalyst, the fouling of the process equipment, and in particular the separation and distillation equipment. As a result, the refiner is forced to reduce the conversion of heavy loads to avoid stopping the hydroconversion unit.

The formation of these sediments in hydrotreatment and hydroconversion processes therefore depends very strongly on the quality of the load and the severity of the operation. Specifically, the asphaltenes present in the feed are mainly converted by dealkylation under severe hydroconversion conditions and thus form molecules with highly condensed aromatic rings that precipitate as sediments. Hydroconversion processes of heavy hydrocarbon feeds are well known to those skilled in the art. In particular,

the conventional heavy-lift conversion schemes comprise a solvent deasphalting step (SDA for Solvent DeAsphalting) and a hydroconversion step carried out in a fixed bed, in a moving bed, in a bubbling bed and / or in a hybrid bed. The hydroconversion stages being carried out in fixed bed, moving bed, bubbling bed and / or hybrid bed depending on the feedstock to be treated, these steps therefore always contain at least one catalyst which is maintained in the reactor during the surgery. In the present application, the term "hybrid bed" refers to a mixed bed of catalysts of very different particle size, simultaneously comprising at least one catalyst which is maintained in the reactor and at least one entrained catalyst (so-called "slurry" according to the English terminology). Saxon) which enters the reactor with the feed and is driven out of the reactor with the effluents. Deasphalting and hydroconversion are conventionally carried out successively. There are in particular two types of heavy-load conversion processes combining deasphalting and hydroconversion:

- A first type of process, known as the "indirect route", implements the deasphalting unit placed upstream of the hydroconversion unit. In this way, the feed is treated at least in part in a deasphalting unit before being sent at least in part to a hydroconversion unit comprising one or more hydroconversion reactors in the presence of hydrogen. US Pat. No. 7,214,308 thus describes a process for the conversion of atmospheric or vacuum residues from the distillation of heavy crude oils, in which the residue is first sent to a solvent deasphalting unit producing a flow of DAO and a solvent. asphalt flow, the two streams being then treated separately in reactors operating as a bubbling bed. The process then allows for a higher conversion level of the residue since the separate hydroconversion of the DAO stream implements a specific DAO treatment catalyst and can be operated to achieve further conversion. A major disadvantage of the indirect route is the large size required for the deasphalter leading to significant investment and operating costs.

a second type of process, known as the "direct route", implements a deasphalting unit placed downstream of the hydroconversion unit. In general, in this type of process, an atmospheric distillation step, and optionally a vacuum distillation step following the atmospheric distillation step, is carried out between the two unitary stages consisting of hydroconversion and deasphalting. This is the case, for example, of the process described in patent FR 2 753 984, in which a heavy charge is first sent to a hydroconversion section comprising at least one three-phase reactor containing a bubbling bed hydroconversion catalyst and hydrogen and operating at an upward flow of liquid and gas. The conditions applied in the hydroconversion reaction section make it possible to obtain a liquid effluent with reduced Conradson carbon content, in metals, in nitrogen and in sulfur. This effluent is then separated into several fractions, including one or more residual fractions: the hydroconverted liquid effluent is sent to an atmospheric distillation zone producing a distillate and an atmospheric residue, and at least a part of the atmospheric residue is sent to a zone The vacuum residue is then sent at least partly into a deasphalting section in which a liquid-liquid extractor is used. using a solvent under deasphalting conditions known to those skilled in the art to obtain a DAO and a residual asphalt. The DAO thus obtained is then subjected to hydrotreatment, either in a fixed bed, in a moving bed, in a bubbling bed and / or in a hybrid bed, under conditions which make it possible to reduce in particular its content of metals, sulfur, Conradson carbon and nitrogen and obtain, after a further separation by distillation, a gaseous fraction, an atmospheric distillate that can be split into a gasoline and diesel fraction then sent to the fuel pool and a heavier hydrotreated fraction. This heavier fraction can then be sent to a catalytic cracking or catalytic hydrocracking section, for example.

Documents US 2010 / 320122A, US 6,017,441, US 3,905,892, US 4,176,048, US 2012 / 061293A and US Pat. No. 8,287,720 describe various possible configurations for the direct route, in which a first hydroconversion step followed by the step of deasphalting is carried out. the heavy cut resulting from an intermediate separation of the hydroconverted effluent, followed by a second hydroconversion, hydrotreatment or hydrocracking step of the DAO. In these configurations, coke and sediment formation can still occur during the second hydroconversion stage in the case where the DAO is co-treated with a feed containing asphaltenes. In addition, a large amount of asphalt is produced during the deasphalting step after the first step of low asphaltene conversion hydroconversion, as in the case of the scheme proposed in US Patent 4,176,048. This asphalt is a low value product that is difficult to convert into fuel. Another configuration according to the direct route consists of carrying out the step of deasphalting the heavy cuts after a hydroconversion step thus making it possible to minimize the quantity of asphalt produced, then of recycling the DAO at the inlet of the first zone of hydroconversion or in fractionation zones upstream of the first hydroconversion zone, as described in the patent applications FR 2 964 388 and FR 2 999 599. This configuration requires a significant increase in the volume of the reaction zones as well as the zones of separation increasing the investment required and the operating cost compared to a conversion process without recycling of CAD. In addition, in this configuration, coke and sediment formation problems can still occur in the hydroconversion stage where the DAO is recycled and co-treated with the asphaltenes-containing heavy feedstock.

Objectives and summary of the invention

The present invention aims to solve, at least partially, the problems mentioned above in connection with the heavy-load conversion processes of the prior art incorporating hydroconversion and deasphalting steps.

In particular, one of the objectives of the invention is to provide a process for converting heavy hydrocarbon feedstocks incorporating hydroconversion and deasphalting steps in which the effluent stability is improved for a given level of heavy load conversion, thus making it possible to further the conversion in the process, that is to say to carry out the hydroconversion so as to obtain a higher conversion rate.

Another object of the invention is to provide such a method in which the formation of coke and sediment is limited during the hydroconversion, thus reducing the problems of deactivation of the catalysts used in the reaction zones and fouling of the equipment used. implemented in the process.

Another objective of the invention is still to provide a good quality DAO, that is to say having a reduced content of nitrogen, sulfur, metals and Conradson carbon.

Thus, to achieve at least one of the above objectives, among others, the present invention provides a method for converting a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling point. at least 300 ° C, and containing sulfur, Conradson carbon, metals, and nitrogen, comprising the following successive steps: an initial hydroconversion step (ai) of at least a portion of said hydrocarbon heavy charge in the presence of hydrogen in an initial hydroconversion section, carried out under conditions making it possible to obtain a reduced-rate liquid effluent; sulfur, Conradson carbon, metals, and nitrogen;

- (n-1) additional hydroconversion stage (s) (a, ·) in (n-1) additional hydroconversion section (s), in the presence of hydrogen, of at least a part or all of the liquid effluent resulting from the preceding hydroconversion stage (a _/ -i) or optionally a heavy fraction resulting from an optional intermediate separation step (b _y ) in a separation section intermediate between two consecutive hydroconversion steps separating part or all of the liquid effluent from the preceding hydroconversion stage (a) to produce at least one heavy fraction boiling predominantly at a temperature greater than or equal to 350 ° C , the (n-1) additional hydroconversion stage (s) (a, ·) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur content, Conradson carbon, metals, and nitrogen,

where n is the total number of hydroconversion steps, where n is greater than or equal to 2, where / is an integer from 2 to n and y is an integer from 1 to (n-1), and the hydroconversion sections initial and additional (s) each comprising at least one triphasic reactor containing at least one hydroconversion catalyst;

a first fractionation step (c) in a first fractionation section of part or all of the hydroconverted liquid effluent from the last additional hydroconversion stage (a _n ) producing at least one heavy cup boiling predominantly at a temperature greater than or equal to 350 ° C, said heavy cup containing a residual fraction boiling at a temperature greater than or equal to 540 ° C;

a step of deasphalting (d) in a deasphalter of a part or all of said heavy cut resulting from the fractionation step (c), with at least one hydrocarbon solvent, to obtain a deasphalted oil DAO and an asphalt residual;

optionally a second fractionation step in a second fractionation section of a part or all of the DAO resulting from the deasphalting stage (d) into at least one heavy fraction of DAO and a light fraction of DAO;

a recycling step (f) of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a, ·) and / or an intermediate separation step (b _y ). The heavy hydrocarbon feedstock preferably has a sulfur content of at least 0.1% by weight, a Conradson carbon content of at least 0.5% by weight and a C ₇ asphaltene content of at least 1%. weight, and a metal content of at least 20 ppm by weight.

The heavy hydrocarbon feedstock may be a crude oil or consist of atmospheric residues and / or vacuum residues resulting from the atmospheric distillation and / or under vacuum of a crude oil, and preferably consists of vacuum residues from vacuum distillation of crude oil.

According to one embodiment of the invention, said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating as a bubbling bed, with an upward flow of liquid and gas.

According to an implementation of the invention, the three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating in a hybrid bed, said hybrid bed comprising at least one catalyst maintained in said three-phase reactor and at least one catalyst driven out said triphasic reactor.

According to one embodiment of the invention, the initial hydroconversion stage (ai) is carried out under an absolute pressure of between 2 and 38 MPa, at a temperature of between 300 ° C. and 550 ° C., at a space velocity hourly WH relative to the volume of each triphasic reactor between 0.05 h ¹ and 10 h ¹ and under a quantity of hydrogen mixed with the hydrocarbon heavy load of between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter ( m ³ ) heavy load of hydrocarbons.

According to one embodiment of the invention, the additional hydroconversion step (s) (a _n ) are carried out at a temperature of between 300 ° C. and 550 ° C., and greater than the temperature operated at the hydroconversion stage. initial (ai), under a quantity of hydrogen mixed with the hydrocarbon heavy load of between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of heavy load of hydrocarbons and less than the quantity of hydrogen performed at the initial hydroconversion stage (ai), at an absolute pressure of between 2 and 38 MPa, and at a space velocity WH of the volume of each triphasic reactor between 0.05 h ¹ and 10 h ¹ .

According to one embodiment of the invention, the intermediate separation section comprises one or more flash balloons arranged in series, and / or one or more steam and / or hydrogen stripping columns, and / or a atmospheric distillation column, and / or a vacuum distillation column, and is preferably constituted by a single flash tank. According to an implementation of the invention, the first fractionation section comprises one or more flash balloons arranged in series, and / or one or more stripping columns with steam and / or hydrogen, and / or a atmospheric distillation column, and / or a vacuum distillation column, and is preferably constituted by a set of several flash balloons in series and atmospheric distillation columns and under vacuum.

According to one embodiment of the invention, the deasphalting step (d) is carried out in an extraction column at a temperature of between 60 ° C. and 250 ° C. with at least one hydrocarbon solvent having from 3 to 7 atoms. carbon, and a solvent / filler ratio (volume / volume) of between 3/1 and 16/1, and preferably between 4/1 and 8/1.

According to one embodiment of the invention, a part of the hydrocarbon heavy load is sent to at least one additional hydroconversion section and / or in at least one intermediate separation section and / or in the first fractionation section. and / or in the deasphalter.

According to one embodiment of the invention, an external hydrocarbon feed is sent to the process in the initial hydroconversion section and / or in at least one additional hydroconversion section and / or in at least one intermediate separation section. and / or in the first fractionation section and / or in the deasphalter.

According to an implementation of the invention, the method further comprises at least one recycling step:

recycling (h) part or all of the light fraction of the DAO resulting from step (e) in the initial hydroconversion section and / or in at least one additional hydroconversion section and / or in at least one intermediate separation section and / or in the first fractionation section;

recycling (r ₂ ) a portion of the heavy fraction of the DAO resulting from step (f) into the first fractionation section;

recycling (r ₃ ) a portion of the DAO resulting from step (d) in the first fractionation section;

recycling (r ₄ ) of part or all of the residual asphalt resulting from step (d) in the initial hydroconversion section and / or in at least one additional hydroconversion section;

recycling (r ₅ ) of a portion of the hydroconverted liquid effluent of a given additional hydroconversion section:

- in the initial hydroconversion section, and / or in another additional hydroconversion section positioned upstream of said given section, and / or

in an intermediate separation section positioned upstream of said given section;

recycling (r ₆ ) a portion of the heavy fraction and / or part or all of one or more intermediate fractions from a given intermediate section:

- in the initial hydroconversion section, and / or

in an additional hydroconversion section positioned upstream of said given intermediate section, and / or

in another intermediate separation section positioned upstream of said given section;

recycling (r ₇ ) a part of the heavy fraction and / or a part or all of one or more intermediate fractions resulting from the first fractionation section:

- in the initial hydroconversion section, and / or

- in an additional hydroconversion section, and / or

in an intermediate separation section.

According to one embodiment of the invention, n is equal to 2.

According to one embodiment of the invention, the process comprises recycling (f) all of the DAO resulting from stage (d) or all of the heavy fraction resulting from the second fractionation stage (e) at the last additional hydroconversion stage (a, ·), and preferably in the additional hydroconversion stage (a ₂ ) when n is 2 and in addition all of the liquid effluent from the step (ai) is sent to step (bi), all of the heavy fraction resulting from step (bi) is sent in step (a ₂ ), all of the hydroconverted liquid effluent from step (a ₂ ) is sent in step (c), and the entire heavy cut from step (c) is sent to step (d).

According to one embodiment of the invention, the process comprises recycling (f) all of the DAO resulting from stage (d) or all of the heavy fraction resulting from the second fractionation stage (e) at an intermediate separation step (b _y ), and preferably at the intermediate separation step (bi) between the initial hydroconversion step (a 1) and the additional hydroconversion step (a ₂ ) when n is equal to 2 and in addition all the liquid effluent from step (ai) is sent to step (bi), all of the heavy fraction from step (bi) is sent to step (a ₂ ), the entire effluent hydroconverted liquid from step (a ₂ ) is sent in step (c), and all of the heavy cut from step (c) is sent to step (d).

According to an implementation of the invention, the method does not include an intermediate separation step (b _y -) and comprises the recycling (f) of all the DAO resulting from step (d) to the last additional hydroconversion stage (a, ·), and preferably in the additional hydroconversion stage (a ₂ ) when n is equal to 2 and in addition all of the liquid effluent resulting from the stage ( a1) is sent to step (a ₂ ), all of the hydroconverted liquid effluent from step (a ₂ ) is sent in step (c), and all of the heavy cut resulting from step (c) is sent to step (d).

According to one embodiment of the invention, the hydroconversion catalyst of the at least one triphasic reactor of the initial hydroconversion section and the additional hydroconversion section (s) contains at least one non-group VIII metal. -noble selected from nickel and cobalt and at least one Group VIB metal selected from molybdenum and tungsten, and preferably comprising an amorphous support.

Other objects and advantages of the invention will appear on reading the following detailed description of the method, as well as examples of particular implementation of the invention, given by way of non-limiting examples, the description being partly with reference to the accompanying figures described below.

Brief description of the figures

Figure 1 is a block diagram of implementation of the conversion method according to the invention.

Fig. 2 is a schematic diagram of the method according to a first embodiment wherein at least a portion of a heavy fraction of the DAO is recycled to a second hydroconversion section.

Fig. 3 is a flow diagram of the method according to a third embodiment wherein at least a portion of the DAO is recycled to the intermediate separation section at the two hydroconversion sections.

Fig. 4 is a schematic diagram of the method according to a second embodiment wherein at least a portion of the DAO is recycled to a second hydroconversion section.

FIG. 5 is a diagram of the method according to a fourth embodiment in which at least a part of the CAD is recycled in a second section hydroconversion succeeding a first hydroconversion section without intermediate separation.

In the figures, the same references designate identical or similar elements.

Description of the invention

The process for converting heavy hydrocarbon feedstocks according to the invention incorporates a hydroconversion of said feeds and a deasphalting of at least a portion of the hydroconverted effluent in the form of a succession of specific steps.

In the remainder of the description, reference is made to FIG. 1 which illustrates the general implementation of the conversion method according to the invention.

In the present invention, it is proposed to simultaneously improve the level of conversion and the stability of the liquid effluents by a sequence comprising at least two successive hydroconversion stages, which can be separated by an intermediate separation step, and at least one step deasphalting a heavy fraction of the effluent from the hydroconversion, with a recycling of at least a portion of the DAO downstream of the first hydroconversion stage. DAO is either recycled at the end of the deasphalter or after having undergone a fractionation step producing a heavy fraction of the DAO which then constitutes the part of the recycled DAO. This configuration makes it possible to achieve a conversion of the heavy hydrocarbon charge of greater than 70%, and preferably greater than 80%, this level of conversion not always being able to be achieved by using the conventional methods which are limited by the stability of the liquid effluents.

The net conversion is defined as the ratio of the (residue rate in the feed - the rate of the residue in the product) / (the rate of residue in the feed), for the same point of load-product cut; typically this cutting point is between 450 ° C and 550 ° C, and often about 540 ° C; in this definition, the residue being the fraction boiling from this cutting point, for example, the fraction 540 ° C +.

Thus, there is provided a method for converting a heavy hydrocarbon feedstock, for example a crude oil or the heavy hydrocarbon fraction resulting from the atmospheric or vacuum distillation of a crude oil, said feedstock containing a fraction of a hydrocarbon feedstock. at minus 50% having a boiling temperature of at least 300 ° C, comprising the following successive steps:

an initial hydroconversion step (ai) of at least a portion of said hydrocarbon heavy load in the presence of hydrogen in an initial hydroconversion section Ai, carried out under conditions making it possible to obtain a liquid effluent with a content reduced to sulfur, Conradson carbon, metals, and nitrogen;

- (n-1) additional hydroconversion stage (s) (a, ·) in (n-1) additional hydroconversion section (s) A, ·, in the presence of hydrogen, d at least some or all of the liquid effluent from the preceding hydroconversion step (a) or optionally a heavy fraction from an optional intermediate separation step (b _y ) between two stages of consecutive hydroconversion separating part or all of the liquid effluent from the preceding hydroconversion stage (a) to produce at least one heavy fraction boiling predominantly at a temperature greater than or equal to 350 ° C, the (n-1 ) additional hydroconversion stage (s) (a, ·) being performed to obtain a hydroconverted liquid effluent with reduced sulfur, Conradson carbon, metals, and nitrogen;

where n is the total number of hydroconversion steps, where n is greater than or equal to 2, where / is an integer from 2 to n and y is an integer from 1 to (n-1), and the hydroconversion sections initial - and additional (s) A, · each comprising at least one triphasic reactor containing at least one hydroconversion catalyst;

a first fractionation step (c) in a first fractionation section C of part or all of the hydroconverted liquid effluent resulting from the last additional hydroconversion stage (a _n ) to produce at least one heavy cut boiling predominantly at a temperature greater than or equal to 350 ° C, said heavy cup containing a residual fraction boiling at a temperature greater than or equal to 540 ° C;

a step of deasphalting (d) in a deasphalter D of part or all of said heavy cut resulting from the fractionation step (c), with at least one hydrocarbon solvent, in order to obtain a deasphalted oil DAO and a residual asphalt;

- optionally a second fractionation step (e) in a second fractionation section E of a part or all of the DAO from the deasphalting step (d) into at least a heavy fraction of DAO and a light fraction of CAD;

a recycling step (f) of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a, ·) and / or an intermediate separation step (b _y ). According to one preferred embodiment, the method according to the invention contains two hydroconversion stages, and an optional intermediate separation stage between these two hydroconversion stages. According to this implementation, n is equal to 2, and the method then comprises:

an additional hydroconversion stage (a ₂ ) in an additional hydroconversion section A ₂ , in the presence of hydrogen, of at least some or all of the liquid effluent resulting from the initial hydroconversion stage _(a}) or optionally a heavy fraction that an optional intermediate separation stage _(b}) between the steps of initial hydroconversion _(a}) and additional ₍₂₎ separating part or all of the liquid effluent from the initial hydroconversion step (a ₎ ) to produce at least one heavy fraction boiling predominantly at a temperature greater than or equal to 350 ° C, the additional hydroconversion step (a ₂ ) being carried out to obtain a hydroconverted liquid effluent with reduced sulfur content, Conradson carbon, metals, and nitrogen,

the initial and additional hydroconversion sections A ₂ each comprising at least one triphasic reactor containing at least one hydroconversion catalyst;

a first fractionation step (c) in a first fractionation section C of part or all of the hydroconverted liquid effluent resulting from the additional hydroconversion stage (a ₂ ) to produce at least one heavy fraction boiling predominantly at a temperature greater than or equal to 350 ° C, said heavy cup containing a residual fraction boiling at a temperature greater than or equal to 540 ° C;

- optionally a second fractionation step (e) in a second fractionation section E of a part or all of the DAO from the deasphalting step (d) into at least a heavy fraction of DAO and a light fraction of CAD; a recycling step (f) of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a ₂ ) and / or an intermediate separation step (b ₎ ).

The DAO obtained by the process according to the invention contains no or very few C ₇ asphaltenes, compounds known to inhibit the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly called cokes, and by their tendency to produce sediments which strongly limit the operability of the hydrotreatment and hydroconversion units. The DAO obtained by the process according to the invention is also more aromatic than a DAO produced from a heavy oil charge resulting from the primary fractionation of the crude oil (so-called "straight run" according to the English terminology) because it comes from an effluent that has previously undergone a high level of hydroconversion.

The mixture of at least a portion of the DAO and the effluent from the first hydroconversion section (s) in the process according to the invention makes it possible to feed the posterior hydroconversion stage (s) with a feed having a reduced C ₇ asphaltene content and higher aromatics content compared to a process comprising a hydroconversion unit without recycle of the DAO, and with respect to a process comprising a hydroconversion unit with recycling of the DAO upstream of a first hydroconversion or hydrotreatment step. As a result, it is possible to impose more severe operating conditions in the process according to the invention, in particular in the additional hydroconversion stages, and thus achieve higher levels in terms of conversion of the feedstock, while by limiting the production of sediments.

The effluent from the last additional hydroconversion stage is separated into several sections. Deasphalting is then performed on the heavy cup (s) produced in this separation step. The use of these cuts obtained at the highest conversion level thus makes it possible to minimize the size required for the deasphalter and to minimize the amount of asphalt produced. According to the invention, the DAO extracted by deasphalting is always recycled after the initial hydroconversion stage, either at the inlet of one of the intermediate separation sections, or at the inlet of one of the additional hydroconversion sections. preferably at the inlet of the section of the last additional hydroconversion step. According to these two implementations, the size of The reactors of the first hydroconversion sections are not impacted, and according to the second implementation, neither the size of the intermediate separation equipment nor the size of the reactors of the prior stages of hydroconversion are affected. Injection of the DAO downstream of the initial hydroconversion section makes it possible to avoid the prior hydrogenation of the DAO thus preserving its aromatic character (characterized by the aromatic carbon content measured by the ASTM D 5292 method) which provides a gain on the stability of the liquid effluents of the areas where the highest conversion levels are reached. An operation to achieve higher conversion rates can thus be envisaged in the method according to the invention.

Charge

The feedstock treated in the process according to the invention is a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling point of at least 300 ° C, preferably at least 350 ° C, and even more preferably at least 375 ° C.

This heavy load of hydrocarbons can be a crude oil, or come from the refining of a crude oil or the treatment of another hydrocarbon source in a refinery.

Preferably, the feedstock is a crude oil or consists of atmospheric residues and / or vacuum residues from the atmospheric distillation and / or vacuum of a crude oil.

The heavy hydrocarbon feedstock may also consist of atmospheric and / or vacuum residues resulting from the atmospheric distillation and / or under vacuum of effluents from thermal conversion, hydrotreatment, hydrocracking and / or hydroconversion.

In a preferred manner, the feedstock consists of residues under vacuum. These vacuum residues generally contain a fraction of at least 50% having a boiling point of at least 450 ° C, and most often at least 500 ° C, or at least 540 ° C. ° C. Vacuum residues can come directly from crude oil, other refining units, such as, among others, the hydrotreating of residues, the hydrocracking of residues, and the visbreaking of residues. Preferably, the vacuum residues are vacuum residues from the column of the vacuum distillation of the primary fractionation of crude (so-called "straight run" in the English terminology).

The feed may also be vacuum distillate, either directly from crude oil or from other refinery units, such as, among others, cracking units, such as Fluid Catalytic Cracking (FCC) and hydrocracking, and thermal conversion units, such as coking units or visbreaking units.

It may also consist of aromatic cuts extracted from a unit for producing lubricants, deasphalted oils from a deasphalting unit (refining the deasphalting unit), asphalts from a deasphalting unit ( residues of the deasphalting unit).

The heavy hydrocarbon feed may also be a residual fraction resulting from the direct liquefaction of coal (an atmospheric residue and / or a vacuum residue resulting for example from the H-Coal ™ process), a vacuum distillate resulting from the direct liquefaction coal, such as the H-Coal ™ process, or a residual fraction resulting from the direct liquefaction of the lignocellulosic biomass alone or mixed with coal and / or a petroleum fraction.

All these fillers can be used to constitute the hydrocarbon heavy load treated according to the invention, alone or as a mixture.

The heavy hydrocarbon feed treated according to the invention contains impurities, such as metals, sulfur, nitrogen and Conradson carbon. It may also contain insoluble heptane, also called C ₇ asphaltenes. The metal contents may be greater than or equal to 20 ppm by weight, preferably greater than or equal to 100 ppm by weight. The sulfur content may be greater than or equal to 0.1%, even greater than or equal to 1%, and may be greater than or equal to 2% by weight. The level of C ₇ asphaltenes (insoluble compounds with heptane according to the standard NFT60-115 or the ASTM D 6560 standard) amounts to at least 1% and is often greater than or equal to 3% by weight. C ₇ asphaltenes are compounds known to inhibit the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly known as cokes, and by their tendency to produce sediments which severely limit the operability of the coke units. hydrotreating and hydroconversion. The Conradson carbon content may be greater than or equal to 0.5%, or even at least 5% by weight. The Conradson carbon content is defined by ASTM D 482 and represents for the skilled person a well-known evaluation of the amount of carbon residues produced after pyrolysis under standard conditions of temperature and pressure. Initial hydroconversion stage (ai)

According to the invention, the heavy hydrocarbon feedstock is treated in the presence of hydrogen in a first hydroconversion stage (ai), within an initial hydroconversion section A-i. The initial hydroconversion section comprises one or more three-phase reactors containing at least one hydroconversion catalyst, the reactors being able to be arranged in series and / or in parallel. These reactors may, in addition, be reactors of fixed bed type, moving bed, bubbling bed, and / or hybrid bed, depending on the load to be treated.

The invention is particularly suitable for three-phase reactors operating as a bubbling bed, with an upward flow of liquid and gas. Thus, this initial hydroconversion step (ai) is advantageously carried out in an initial hydroconversion section i comprising one or more three-phase hydroconversion reactors, which can be in series and / or in parallel, operating as a bubbling bed, typically using the technology and under the conditions of the H-Oil ™ process as described for example in US Pat. Nos. 4,521,295 or US 4,495,060 or US Pat. No. 4,457,831 or US Pat. No. 4,354,852, or in AlChE article, March 19, 23, 1995, Houston, Texas, paper number 46d, "Second generation ebullated bed technology", or in Chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" of the book "Catalysis by Transition Metal Sulphides", published by Technip Editions in 2013. According to this implementation, each triphasic reactor is operated in a fluidized bed called bubbling bed. Each reactor advantageously comprises a recirculation pump for maintaining the catalyst in a bubbling bed by continuously recycling at least a portion of a liquid fraction advantageously withdrawn at the top of the reactor and reinjected at the bottom of the reactor.

The first hydroconversion step (a-i) is carried out under conditions making it possible to obtain a liquid effluent with a reduced sulfur content, Conradson carbon, metals, and nitrogen.

In this step (ai), the charge is preferably converted under specific hydroconversion conditions. Step (a) is preferably carried out under an absolute pressure of between 2 MPa and 38 MPa, more preferably between 5 MPa and 25 MPa and even more preferably between 6 MPa and 20 MPa, at a temperature of between 300 and 300 MPa. ° C and 550 ° C, more preferably between 350 ° C and 500 ° C and preferably between 370 ° C and 450 ° C. The hourly space velocity (WH) with respect to the volume of each triphasic reactor is preferably between 0.05 h ¹ and 10 h ¹ . According to a preferred embodiment, the WH is between 0.1 h ¹ and 10 h ¹ , more preferably between 0.1 h ¹ and 5 h ¹ and even more preferably between 0.15 h ¹ and 2 h ¹ . According to another implementation, the WH is between 0.05 h ¹ and 0.09 h ¹ . The amount of hydrogen mixed with the feedstock is preferably between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of liquid feed, preferably between 100 and 2000 Nm ³ / m ³ and very preferred between 200 and 1000 Nm ³ / m ³ .

Since the initial hydroconversion stage (ai) is carried out in a fixed bed, in a moving bed, in a bubbling bed and / or in a hybrid bed depending on the feedstock to be treated, this step therefore contains at least one hydroconversion catalyst which is kept in the reactor.

The hydroconversion catalyst used in the initial hydroconversion stage (a-i) of the process according to the invention may contain one or more elements from groups 4 to 12 of the periodic table of the elements, which may be deposited on a support or not. It is advantageous to use a catalyst comprising a support, preferably amorphous, such as silica, alumina, silica-alumina, titanium dioxide or combinations of these structures, and very preferably alumina.

The catalyst may contain at least one non-noble group VIII metal selected from nickel and cobalt, and preferably nickel, said group VIII element being preferably used in combination with at least one Group VI B metal selected from molybdenum and tungsten, and preferably the Group VIB metal is molybdenum.

In the present description, 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 VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new classification IU PAC.

Advantageously, the hydroconversion catalyst used in the initial hydroconversion stage (ai) comprises an alumina support and at least one Group VIII metal chosen from nickel and cobalt, preferably nickel, and at least one metal from the group. group VIB selected from molybdenum and tungsten, preferably molybdenum. Preferably, the hydroconversion catalyst comprises nickel as part of group VIII and molybdenum as part of group VIB.

The metal content of the non-noble group VIII, in particular nickel, is advantageously between 0.5% to 10% expressed by weight of metal oxide (in particular NiO), and preferably between 1% to 6%. % weight, and the metal content of the group VIB, in particular in molybdenum, is advantageously between 1% and 30% expressed by weight of metal oxide (in particular of molybdenum trioxide MoO ₃ ), and preferably between 4% and 20% by weight. The metal contents are expressed as weight percent of metal oxide relative to the weight of the catalyst.

This catalyst is advantageously used in the form of extrudates or beads. The balls have for example a diameter of between 0.4 mm and 4.0 mm. The extrudates have for example a cylindrical shape with a diameter of between 0.5 and 4.0 mm and a length of between 1 and 5 mm. Extrusions can also be objects of a different shape such as trilobes, regular or irregular tetralobes, or other multilobes. Catalysts of other forms can also be used.

The size of these different forms of catalysts can be characterized using the equivalent diameter. The equivalent diameter is defined as 6 times the ratio between the volume of the particle and the external surface of the particle. The catalyst used in the form of extrusions, beads or other forms therefore has an equivalent diameter of between 0.4 mm and 4.4 mm. These catalysts are well known to those skilled in the art.

In one of the implementations according to the invention, the initial hydroconversion stage (ai) is carried out in a hybrid bed, comprising simultaneously at least one catalyst which is maintained in the reactor and at least one entrained catalyst which enters the reactor with the charge and which is driven out of the reactor with the effluents. In this case, a type of entrained catalyst, also called "slurry" according to the English terminology, is therefore used in addition to the hydroconversion catalyst which is maintained in the bubbling bed reactor. The catalyst entrained has as a difference a particle size and a density suitable for its training. The term "entrainment of the dispersed catalyst" is understood to mean its circulation in the three-phase reactor (s) by the liquid flows, said catalyst circulating with the feedstock in the said three-phase reactor (s), and being withdrawn from the said triphasic reactor (s) with the liquid effluent produced. These catalysts are well known to those skilled in the art.

The entrained catalyst may advantageously be obtained by injecting at least one active phase precursor directly into the hydroconversion reactor (s) and / or into the feedstock prior to introducing said feed into the hydroconversion stage (s). The addition of precursor may be introduced continuously or discontinuously (depending on the operation, the type of charges processed, product specifications sought and operability). According to one or more embodiments, the precursor (s) entrained catalyst is (are) premixed (s) with a hydrocarbon oil composed for example of hydrocarbons of which at least 50% by weight relative to the total weight of the hydrocarbon oil have a boiling point between 180 ° C and 540 ° C to form a diluted precursor premix. According to one or more embodiments, the precursor or premix of diluted precursor is dispersed in the heavy hydrocarbon feedstock, for example by dynamic mixing (for example using a rotor, a stirrer, etc.). ), by static mixing (for example by means of an injector, by gavage, via a static mixer, etc.), or only added to the charge to obtain a mixture. Any mixing and stirring techniques known to those skilled in the art can be used to disperse the precursor or diluted precursor mixture into the feed of one or more hydroconversion steps.

The at least one active phase precursor (s) of the unsupported catalyst may or may be in liquid form, such as, for example, precursors of metals soluble in organic media, for example molybdenum octoates and / or molybdenum naphthenates, or water-soluble compounds, such as, for example, phosphomolybdic acids and / or ammonium heptamolybdates.

Said entrained catalyst can be formed and activated ex situ outside the reactor under conditions suitable for activation and then injected with the feedstock. Said entrained catalyst can also be formed and activated in situ under the reaction conditions of one of the hydroconversion stages.

According to one embodiment, said driven catalyst can be supported. In this case, the supported catalyst can advantageously be obtained:

- by grinding the supported hydroconversion catalyst, fresh or spent or by grinding a mixture of fresh and spent catalysts, or

- Impregnation of at least one active phase precursor on a support having a particle size suitable for its drive and preferably a size between 0.001 and 100 pm. The active phase may be that described above for the hydroconversion catalyst used in the initial hydroconversion stage (a-i), as well as the support. Their description is not repeated here.

In one of the implementations of the process according to the invention, a different hydroconversion catalyst is used in each reactor of this initial hydroconversion stage (ai), the catalyst proposing that each reactor be adapted to the feedstock sent in this reactor. reactor. In one of the implementations of the process according to the invention, several types of catalyst are used in each reactor.

In one of the implementations of the process according to the invention, each reactor contains one or more catalysts adapted to a bubbling bed operation, and possibly one or more additional entrained catalysts.

As is known, and for example described in patent FR 3,033,797, the hydroconversion catalyst, when used, may be partly replaced by fresh catalyst, and / or used catalyst but of catalytic activity. higher than the spent catalyst to be replaced, and / or regenerated catalyst, and / or catalyst rejuvenated (catalyst from a rejuvenation zone in which the bulk of the deposited metals are removed, before sending the spent catalyst and rejuvenated in a regeneration zone in which the carbon and the sulfur contained therein are removed, thereby increasing the activity of the catalyst), by withdrawing the used catalyst, preferably at the bottom of the reactor, and introducing the replacement catalyst either at the top or at the bottom of the reactor. This spent catalyst replacement is preferably carried out at regular time intervals, and preferably by puff or almost continuously. The replacement of used catalyst may be done in whole or in part by used catalyst and / or regenerated and / or rejuvenated from the same reactor and / or another reactor of any hydroconversion step. The catalyst may be added with the metals as metal oxides, metals as metal sulfides, or after preconditioning. For each reactor, the replacement rate of the spent hydroconversion catalyst with fresh catalyst is advantageously between 0.01 kg and

10 kg per cubic meter of treated feedstock, and preferably between 0.1 kg and 3 kg per cubic meter of feedstock treated. This withdrawal and replacement are performed using devices advantageously allowing the continuous operation of this hydroconversion step.

With regard to the replacement at least partly by regenerated catalyst,

It is possible to send the spent catalyst withdrawn from the reactor into a regeneration zone in which the carbon and the sulfur contained therein are eliminated and then to return this regenerated catalyst to the hydroconversion stage. With regard to the replacement at least in part by the rejuvenated catalyst, it is possible to send the spent catalyst withdrawn from the reactor into a rejuvenation zone in which the major part of the deposited metals is removed before sending the spent catalyst. and rejuvenated in a zone of regeneration in which the carbon and sulfur contained therein are removed and then return this regenerated catalyst in the hydroconversion stage.

The initial hydroconversion section A _} can also receive, in addition to the heavy load of hydrocarbons, at least one of the following effluents:

one or more external hydrocarbon feeds (in the sense outside the process according to the invention and different from the initial feedstock), preferably cuts of hydrocarbons external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, or residues under vacuum;

a portion of the heavy fraction resulting from one or more intermediate separation steps (by) carried out between two consecutive additional hydroconversion stages (a,), these steps (a,) and (b _y ) being described below;

a part or all of one or more intermediate fractions resulting from one or more intermediate separation stages (by) carried out between two consecutive additional hydroconversion stages (a,);

a part of the effluent of one or more additional hydroconversion stages

(at ;

a part of the heavy cut and / or of one or more of the intermediate cuts and / or of one or more light cuts resulting from the first fractionation step (c) of the process according to the invention;

a part or all of the residual asphalt produced in the deasphalter D in the deasphalting stage (d);

a part or all of the light fraction of the DAO produced in the second fractionation step (e) of the process according to the invention.

Intermediate separation step (b ·,) - optional

The liquid effluent from the initial step hydroconversion (ai) may then undergo intermediate separation stage _(b}) in an intermediate separation section B ,, performed between the initial step hydroconversion (ai) and an additional hydroconversion step following the initial hydroconversion stage. This additional hydroconversion step is described below. According to the invention, the intermediate separation stage _(b}) is preferred, but it is optional. Indeed, the liquid effluent from the initial hydroconversion stage (ai) may alternatively be sent directly to the additional hydroconversion stage. Preferably, at least a portion of the liquid effluent from the initial step hydroconversion (ai) is sent to the intermediate separation step _(b}).

The intermediate separation step _(b}) separating some or all of the liquid effluent from the initial step hydroconversion (ai) to produce at least one so-called heavy fraction predominantly liquid boiling at a temperature greater than or equal at 350 ° C.

This first intermediate separation step thus produces at least two fractions, the heavy liquid fraction as described above, the other cup or sections being light and intermediate sections (s).

The light fraction thus separated contains dissolved light gases (H ₂ and CC ₄ ), naphtha (fraction boiling at a temperature below 150 ° C), kerosene (fraction boiling between 150 ° C and 250 ° C), and minus a portion of the gas oil (fraction boiling between 250 ° C and 375 ° C).

The light fraction can then be sent at least in part to a fractionation unit (not shown in the figures) where the light gases (H ₂ and C ₁ -C 4) are extracted from said light fraction, for example by passing through a storage tank. flash. The hydrogen gas thus recovered can advantageously be recycled at the inlet of the initial hydroconversion stage (ai).

The fractionation unit where the light fraction can be sent may also comprise a distillation column. In this case, the naphtha, kerosene and diesel fractions of the light fraction sent into said column are separated.

The heavy liquid fraction from the intermediate separation step _(b}), predominantly boiling at a temperature greater than or equal to 350 ° C, contains at least a fraction boiling at a temperature greater than or equal to 540 ° C, called residue under empty (which is the unconverted fraction). The heavy liquid fraction from the intermediate separation step (bi), boiling predominantly at a temperature greater than or equal to 350 ° C, may also contain a fraction boiling between 375 and 540 ° C, called vacuum distillate. It may also possibly contain a portion of the diesel fraction boiling between 250 and 375 ° C.

This heavy liquid fraction is then sent in whole or in part to a second hydroconversion stage (a ₂ ), as described below. The intermediate separation step _(b}) can then separate the liquid effluent from the initial step hydroconversion (ai) as well as two liquid fractions, according to the separation means implemented.

The intermediate separation section B comprises any separation means known to those skilled in the art.

The intermediate separation section B may thus comprise one or more separation equipment as follows: one or more flash balloons arranged in series, one or more steam and / or hydrogen stripping columns, an atmospheric distillation column a vacuum distillation column.

Preferably, this intermediate separation stage _(b}) is performed by one or more flash balls arranged in series.

According to a preferred implementation, the intermediate separation step _(b}) is formed by a single flash drum. Preferably, the flash balloon is at a pressure and a temperature close to the operating conditions of the last reactor of the initial hydroconversion stage (ai). This implementation is preferred because it reduces the number of equipment and therefore the investment cost.

According to another implementation, the intermediate separation step _(b}) is produced by a sequence of several flash balls, operating at different operating conditions from those of the last reactor of the initial stage hydroconversion (ai) , and leading to obtaining at least the light liquid fraction, which can then be sent at least partly to a fractionation unit, and at least the heavy liquid fraction, which is then sent at least in part to a second hydroconversion stage (a ₂ ).

In another implementation, intermediate separation step _(b}) is performed by one or more columns of stripping steam and / or hydrogen. By this means, the effluent from the initial hydroconversion stage (ai) is separated into at least the light liquid fraction and at least the heavy liquid fraction. The heavy liquid fraction is then sent at least partly to a second hydroconversion stage (a ₂ ).

In another implementation; the intermediate separation step _(b}) is performed in an atmospheric distillation column separating the liquid effluent from the initial step hydroconversion (ai). The heavy liquid fraction recovered from the atmospheric distillation column is then sent at least partly to a second hydroconversion stage (a ₂ ).

In another implementation; the intermediate separation step _(b}) is formed by an atmospheric distillation column separating the liquid effluent from step hydroconversion initial (ai), and by a vacuum distillation column receiving the residue of the atmospheric distillation column and producing the heavy liquid fraction which is then sent at least partly to a second hydroconversion stage (a ₂ ) .

The intermediate separation step _(b}) may also be comprised of a combination of the different implementations described above, in a different order from that described above.

Optionally, before being sent to a second hydroconversion stage (a ₂ ) according to the invention, the heavy liquid fraction may be subjected to a stripping step with steam and / or hydrogen using one or more stripping columns, in order to remove from the heavy fraction the compounds having a boiling point below 540 ° C.

The intermediate separation section B can also receive, in addition to part or all of the liquid effluent from the initial hydroconversion stage (a-i), at least one of the following effluents:

a portion of the hydrocarbon heavy feedstock sent to the hydroconversion stage (bypass);

one or more external hydrocarbon feedstocks, preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, residues under vacuum;

a part of the heavy fraction resulting from one or more intermediate By separation stages carried out between two consecutive additional hydroconversion steps (a,), subsequent to step (a1), as detailed below;

a part of the liquid effluent of one or more additional hydroconversion stages (a,) described below;

a part of the heavy cut and / or of one or more of the intermediate cuts and / or of one or more of the light cuts resulting from the first fractionation step (c) detailed below;

a part or all of the DAO produced in the deasphalter D at the deasphalting stage (d);

a part or all of the heavy fraction of the DAO produced in the second fractionation stage (e); a part or all of the light fraction of the DAO produced in the second fractionation stage (e).

In this case, the additional effluent can be sent to the inlet of the intermediate separation section, or between two different equipment of the intermediate separation section, for example between the flash balloons, the stripping columns and / or the distillation columns.

Additional hydroconversion stage (s) (ai) and optional intermediate separation stage (s) (b, ·)

According to the invention, part or all of the effluent resulting from the initial hydroconversion stage (ai), or preferably a part or all of the heavy fraction resulting from the intermediate separation step ( b _} ), is treated in the presence of hydrogen in an additional hydroconversion stage (a ₂ ) carried out in an additional hydroconversion section A ₂ , which follows the initial hydroconversion stage (ai) or optionally the stage intermediate separation (b ₎ ).

The method according to the invention may comprise more than one additional hydroconversion step (a, ·), as well as more than one intermediate separation step (b _y ) between two consecutive additional hydroconversion steps (a, ·). .

Thus, the method according to the invention comprises (n-1) additional hydroconversion stage (s) (a, ·) in (n-1) additional hydroconversion section (s) A, · in the presence of hydrogen, at least some or all of the liquid effluent from the preceding hydroconversion step (a, -i) or optionally a heavy fraction from the optional step of intermediate separation (bj) between two consecutive hydroconversion stages separating part or all of the liquid effluent from the preceding hydroconversion stage (a) to produce at least one heavy fraction boiling predominantly at a temperature greater than or equal to at 350 ° C, the (n-1) additional hydroconversion stage (s) (a, ·) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur content, Conradson carbon, metal, and nitrogen.

n is the total number of hydroconversion steps, with n greater than or equal to 2.

/ and y are indices / is an integer ranging from 2 to n and y being an integer ranging from 1 to

(n-1). The additional hydroconversion section (s) A, each comprise at least one triphasic reactor containing at least one hydroconversion catalyst, as described for the initial hydroconversion section A _} .

The initial hydroconversion step and the additional hydroconversion step (s) are separate steps, performed in different hydroconversion sections.

The (n-1) additional hydroconversion stage (s) (a, ·) are implemented in a manner similar to that described for the initial hydroconversion stage, and their description is not so not repeated here. This applies in particular to the operating conditions, the equipment used, the hydroconversion catalysts used, with the exception of the details given below.

As with the initial hydroconversion step _(a}), the (n-1) step (s) additional hydroconversion (s) (a, ·) are advantageously implemented in sections of initial hydroconversion - \ comprising one or more three-phase hydroconversion reactors, which may be in series and / or in parallel, preferably operating as a bubbling bed, as described above for the initial hydroconversion step (a ₎ ). According to this preferred embodiment, each triphasic reactor is operated in a fluidized bed called bubbling bed. Each reactor advantageously comprises a recirculation pump for maintaining the catalyst in a bubbling bed by continuously recycling at least a portion of a liquid fraction advantageously withdrawn at the top of the reactor and reinjected at the bottom of the reactor.

In these additional hydroconversion steps, the operating conditions may be more severe than in the initial hydroconversion stage, in particular by using a higher reaction temperature, remaining in the range between 300 ° C. and 550 ° C., preferably between 350 ° C and 500 ° C, and more preferably between 370 ° C and 450 ° C, or by decreasing the amount of hydrogen introduced into the reactor, remaining in the range between 50 and 5000 Nm ³ / m ³ of liquid charge, preferably between 100 and 2000 Nm ³ / m ³ , and even more preferably between 200 and 1000 Nm ³ / m ³ . The other parameters of pressure and WH are in ranges identical to those described for the initial hydroconversion stage.

The catalyst used in the reactor (s) of an additional hydroconversion stage may be the same as that used in the reactor (s) of the initial hydroconversion stage, or may also be a catalyst more suitable for hydroconversion of residual cuts containing DAO. In this case, the catalyst may have a porosity of the support or contain metal contents, suitable for hydroconversion of feeds containing cuts of DAO.

With regard to the possible replacement of the used catalyst, the catalyst replacement rate applied in the reactor (s) of an additional hydroconversion stage may be the same as that used for the reactor (s) of the initial hydroconversion stage. , or be more suitable for hydroconversion of residual cuts containing DAO. In this case, the catalyst replacement rate may be lower, suitable for hydroconversion of feeds containing CAD cuts.

The other intermediate separation steps (b _y ) which can be carried out each between two additional hydroconversion steps A · consecutive are also implemented in a manner similar to that described for the intermediate separation step ( b _} ), and the description of these steps (b _y ) is not repeated here.

In a preferred implementation, the method according to the invention always comprises an intermediate separation step (b _y ) between two additional hydroconversion stages (s) (a, ·) consecutive. According to an alternative implementation, the effluent resulting from an additional hydroconversion step (a, ·) is directly sent to another additional hydroconversion stage (a _{/ +} ) as a result of step (a). ·).

According to a preferred implementation, the method comprises a single additional hydroconversion step (a ₂ ), and an intermediate separation step (b ₎ ). With reference to the figures in particular, this is the case where n is equal to 2, with / taking the unique value of 2 and y the unique value of 1.

According to the invention, at least a portion of the DAO resulting from the deasphalting step (d) detailed below, and / or at least a portion of the heavy fraction of the DAO resulting from a second fractionation step ( e) also detailed below, is recycled by being sent to an additional hydroconversion step (a, ·) and / or an intermediate separation step (b _y ). The method according to the invention thus excludes a recycling of the DAO or a heavy fraction of the DAO in the initial hydroconversion stage.

The DAO or the heavy fraction of the DAO thus recycled can then be co-processed in an additional hydroconversion section A, with at least a portion of the effluent from the initial hydroconversion stage (a ₎ ) or a hydroconversion stage additional (a, ·), or more preferably co-processed with at least a portion of the heavy fraction from an intermediate separation step (b _y ).

Each additional hydroconversion section A may also receive, in addition to the effluent resulting from the initial hydroconversion stage or a previous additional hydroconversion stage (a _/ -i) or, more preferably, in addition to the heavy fraction resulting from an intermediate separation step (b _y ), at least one of the following effluents:

a portion of the hydrocarbon heavy feedstock sent to the initial hydroconversion stage (bypass);

one or more external hydrocarbon feeds, preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, or residues under vacuum;

a portion of the heavy fraction resulting from one or more subsequent intermediate separation steps B _y carried out between two consecutive additional hydroconversion stages (a,);

a part or all of one or more intermediate fractions resulting from one or more subsequent intermediate separation steps (b _y ) carried out between two consecutive additional hydroconversion stages (a,);

a part of the effluent of one or more subsequent hydroconversion stages of additional hydroconversion (a, _{+ i} );

a part or all of the heavy fraction of the DAO produced in the second fractionation step (e) of the process according to the invention;

- part or all of the light fraction of the DAO produced in the second fractionation step (e);

a part or all of the residual asphalt produced in the deasphalter D in the deasphalting stage (d).

Each intermediate separation section B _y may also receive, in addition to part or all of the hydroconverted liquid effluent from the initial step hydroconversion (ai) or a preceding additional hydroconversion stage (a, -i), at least one of the following effluents:

a part of the liquid effluent of one or more additional hydroconversion stages (a,) subsequent;

a part of the heavy cut and / or of one or more of the intermediate cuts and / or of one or more of the light cuts resulting from the first fractionation step (c);

a part or all of the heavy fraction of the DAO produced in the second fractionation stage (e);

a part or all of the light fraction of the DAO produced in the second fractionation stage (e).

In this case, the additional effluent can be sent to the inlet of the intermediate separation section B _y , or between two different equipment of the intermediate separation section B _y , for example between the flash balloons, the stripping columns. and / or the distillation columns.

First step of splitting (c)

The hydroconverted liquid effluent from the last additional hydroconversion step (a _n ) then undergoes at least partly a fractionation step (c) in a first fractionation section C. This first fractionation step (c) separates part or all of the effluent from step (a _n ) in several fractions, at least one heavy liquid fraction boiling predominantly at a temperature above 350 ° C., preferably greater than 500 ° C and more preferably greater than 540 ° C. The heavy liquid cup contains a fraction boiling at a temperature above 540 ° C, referred to as vacuum residue (which is the unconverted fraction). It may contain a portion of the gas oil fraction boiling between 250 and 375 ° C and a fraction boiling between 375 and 540 ° C called vacuum distillate.

This first fractionation step therefore produces at least two fractions, the heavy liquid fraction as described above, the other cup or sections being light and intermediate cuts (s).

The first fractionation section C comprises any separation means known to those skilled in the art.

The first fractionation section C may thus comprise one or more separation devices as follows: one or more flash balloons arranged in series, and preferably a sequence of at least two successive flash balloons, one or more stripping columns at the steam and / or hydrogen, an atmospheric distillation column, a vacuum distillation column.

According to one implementation, this first splitting step (c) is performed by a sequence of at least two successive flash balls.

According to another implementation, this first fractionation stage (c) is carried out by one or more stripping columns with steam and / or with hydrogen.

According to another preferred embodiment, this first fractionation step (c) is carried out by an atmospheric distillation column, and more preferably by an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

According to the most preferred implementation, this first fractionation step (c) is carried out by one or more flash flasks, an atmospheric distillation column and a vacuum column receiving the atmospheric residue. This configuration makes it possible to reduce the size of the deasphalter downstream, thus minimizing investment costs and operating costs. The first fractionation section C may also receive, in addition to part or all of the hydroconverted liquid effluent from the last additional hydroconversion step (a _n ), at least one of the following effluents:

a part of the heavy fraction resulting from one or more intermediate separation steps B _y made between two consecutive additional hydroconversion stages (a,);

a part of the liquid effluent of one or more additional hydroconversion stages (a,);

a part of one or more of the intermediate sections resulting from the first fractionation stage (c);

a part of the DAO produced in the deasphalter D in the deasphalting stage (d);

a part of the heavy fraction of the DAO produced in the second fractionation stage (e);

Deasphalting step (d)

The heavy cut resulting from the first fractionation step (c) then undergoes, in accordance with the process according to the invention, all or part of a deasphalting step (d) in a deasphalter D, with at least one hydrocarbon solvent, to extract a DAO and a residual asphalt.

The deasphalter D can also receive at least one of the following effluents:

a portion of the hydrocarbon heavy feedstock sent to the hydroconversion stage (bypass); one or more external hydrocarbon feeds, preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, residues under vacuum;

a portion of the heavy fraction resulting from one or more intermediate separation steps (b /) carried out between two consecutive additional hydroconversion stages (a,) (not shown in FIG. 1);

a part of the liquid effluent of the initial hydroconversion stage (a-i) or of one or more additional hydroconversion stages (a,) (not shown in FIG. 1);

The deasphalting step (d) using a solvent (or SDA for Solvent DeAsphalting in English) is carried out under conditions well known to those skilled in the art. We can thus refer to the article by Billon and others published in 1994 in volume 49, No. 5 of the Revue of the Institut Français du Pétrole, page 495 to 507, in the book "Refining and Conversion of Heavy Products of the oil "by JF Le Page, SG Shatila and M Davidson, Technip Edition, page 17-32 or US Patents 4,239,616; US 4,354,922; US 4,354,928; US 4,440,633; US 4,536,283; and US 4,715,946.

The deasphalting can be carried out in one or more mixer-settlers or in one or more extraction columns. The deasphalter D thus comprises at least one mixer-settler or at least one extraction column.

Deasphalting is a liquid-liquid extraction generally carried out at an average temperature of between 60 ° C. and 250 ° C. with at least one hydrocarbon solvent. The solvents used for deasphalting are low-boiling solvents, preferably paraffinic solvents, and preferably heavier than propane, and preferably having from 3 to 7 carbon atoms. Preferred solvents include propane, butane, isobutane, pentane, isopentane, neopentane, hexane, isohexanes, C ₆ hydrocarbons, heptane, C ₇ hydrocarbons, light essences more or less apolar, as well as mixtures obtained from the aforementioned solvents. Preferably, the solvent is butane, pentane or hexane, and mixtures thereof. The solvent or solvents are optionally added with at least one additive. Useful solvents and additives are widely described in the literature. The solvent / charge (volume / volume) ratios entering the deasphalter D are generally between 3/1 and 16/1, and preferably between 4/1 and 8/1. It is also possible and advantageous to carry out the recovery of the solvent according to the opticritic process, that is to say using a solvent under supercritical conditions in the separation section. This process makes it possible in particular to significantly improve the overall economy of the process.

In the context of the present invention, it is preferred to implement a technique using at least one extraction column and preferably only one (eg the Solvahl ™ process). Advantageously, as in the Solvahl ™ process with a single extraction column, the solvent / charge (volume / volume) ratios entering the deasphalter D are low, typically between 4/1 and 8/1, or even between 4 / 1 and 6/1.

According to one preferred embodiment, the deasphalting is carried out in an extraction column at a temperature of between 60 ° C. and 250 ° C. with at least one hydrocarbon solvent having from 3 to 7 carbon atoms, and a solvent / filler ratio. (volume / volume) between 4/1 and 6/1.

The deasphalter D produces a DAO substantially free of C ₇ asphaltenes and a residual asphalt concentrating most of the impurities of the residue, said residual asphalt being withdrawn.

The yield of DAO is generally between 40% by weight and 95% by weight depending on the operating conditions and the solvent used, and according to the charge sent to the duster D and in particular the quality of the heavy liquid cut from the first fractionation stage (c ).

The following Table 1 gives the ranges of typical operating conditions for deasphalting according to the solvent:

Table 1

The deasphalting conditions are adapted to the quality of the DAO to be extracted and to the feed entering into the deasphalter D.

These conditions allow a significant lowering of the sulfur content, Conradson carbon and the content of C ₇ asphaltenes.

The DAO obtained advantageously has a C ₇ asphaltenes content of less than 2% by weight in general, preferably less than 0.5% by weight, and preferably less than 0.05% by weight, measured as insoluble C ₇ . According to the invention, the CAD thus produced is either sent to a second fractionation step (e) of the process according to the invention, or recycled at least in part to one or more intermediate separation steps (b _j ) and / or directly at the entry of one or more additional hydroconversion steps (a,), and more preferably at the entry of the last additional hydroconversion step (a _n ).

Second stage of fractionation - optional

The DAO from the deasphalting step (d) can undergo, at least in part, a second fractionation in a second fractionation section E, in order to produce at least two fractions.

Preferably, part or all of the DAO from the deasphalting step (d) is sent to this second fractionation step (e).

The second fractionation section E comprises any separation means known to those skilled in the art.

The second fractionation section E may thus comprise one or more separation devices as follows: one or more flash balloons arranged in series, and preferably a sequence of at least two successive flash balloons, one or more stripping columns at the steam and / or hydrogen, an atmospheric distillation column, a vacuum distillation column.

According to one implementation, this second splitting step (e) is performed by a sequence of at least two successive flash balls.

According to another implementation, this second fractionation stage (e) is carried out by one or more stripping columns with steam and / or with hydrogen.

According to another preferred embodiment, this second fractionation step (e) is carried out by an atmospheric distillation column, and more preferably by an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

According to another preferred embodiment, this second fractionation step (e) is carried out by one or more flash balloons, an atmospheric distillation column and a vacuum column receiving the atmospheric residue.

According to another preferred embodiment, this second fractionation step (e) is carried out by a vacuum column. The choice of the equipment of the fractionation section E depends preferably on the choice of the equipment of the first fractionation section C and the charges introduced into the deasphalter D.

According to the process of the invention, the heavy fraction of the DAO thus produced in the second fractionation section E is then recycled at least in part to one or more intermediate separation stages and / or directly to the inlet of one or more several additional hydroconversion steps (a,), and more preferably at the entry of the last additional hydroconversion step (a _n ).

According to one preferred embodiment, the heavy fraction resulting from the first fractionation section C of the process according to the invention is an atmospheric residue which leaves an atmospheric distillation column. The absence of a vacuum distillation column makes it possible to avoid the concentration of sediments and the rapid fouling of the vacuum distillation column. The atmospheric residue thus produced is then sent to the deasphalter D to perform the deasphalting step (d), producing a residual asphalt and a DAO substantially free of C ₇ asphaltenes and sediments, but containing both a distillate fraction. under vacuum and a fraction of residue under vacuum. This DAO thus obtained can then be sent to the second fractionation section E of the process according to the invention, composed of a vacuum distillation column and intended to separate the DAO into at least a light fraction of the DAO whose boiling point is mostly below 500 ° C and at least a heavy fraction of the DAO whose boiling point is mostly above 500 ° C. Since the DAO produced in the deatpaste D is free of sediment and contains almost no more C ₇ asphaltenes, the vacuum distillation column will only foul very slowly, thus avoiding frequent shutdowns and shutdowns for cleaning. of the vacuum distillation column. The heavy fraction of the DAO thus produced is then advantageously recycled at least in part to the inlet of the last additional hydroconversion stage (a _n ).

The method according to the invention therefore improves the stability of the treated liquid effluents during the hydroconversion, and more particularly during the additional hydroconversion stages receiving at least a portion of the DAO and / or the heavy fraction of the DAO, while considerably increasing the conversion of the heavy hydrocarbon feedstock. Recycle step of the DAO or the heavy fraction of the DAO (f)

The method according to the invention comprises the recycling of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a, ·) and / or at an intermediate separation step (b _y ).

This recycling has been previously described in relation to the steps of deasphalting (d) and second fractionation (e).

Recycling step (r ₁ to r ₇ ) other effluents from steps (e)

The process according to the invention may comprise other recycles, the recycled effluents possibly coming from the second fractionation stage (e), the deasphalting stage (d), an additional hydroconversion stage (a, ), or an intermediate separation step (b _j ).

According to one implementation, the method includes recycling (h) of a portion or all of the light fraction of the DAO from step (e) into the hydroconversion initial section - _\ and / or at least one additional hydroconversion section A, and / or in at least one intermediate separation section B _y and / or in the first fractionation section C.

According to one embodiment, the method comprises the recycling (r ₂ ) of a portion of the heavy fraction of the DAO resulting from step (e) in the first fractionation section C.

According to one embodiment, the method comprises the recycling (r ₃ ) of a portion of the DAO resulting from step (d) into the first fractionation section C.

According to one embodiment, the method comprises the recycling (r ₄ ) of part or all of the residual asphalt resulting from step (d) in the initial hydroconversion section Ai and / or in at least an additional hydroconversion section A, ·. Preferably, the residual asphalt is recycled to a hydroconversion section different from that receiving the DAO or the heavy fraction of the DAO.

According to one embodiment, the method comprises the recycling (r ₅ ) of a part of the hydroconverted liquid effluent of an additional hydroconversion section A, · given: - in the initial hydroconversion section Ai, and / or

- in another additional hydroconversion section A, · positioned upstream of said section A, · data, and / or

in an intermediate separation section B _y positioned upstream of said given section A j.

According to one embodiment, the method comprises recycling (r ₆ ) a portion of the heavy fraction and / or a part or all of one or more intermediate fractions from a given intermediate section B _y :

in the initial hydroconversion section A _1; and or

- in an additional hydroconversion section A, · positioned upstream of said intermediate section B _are given, and / or

- In another intermediate separation section B _y positioned upstream of said section B _y given.

According to one embodiment, the method comprises recycling (r ₇ ) a part of the heavy fraction and / or a part or all of one or more intermediate fractions resulting from the first fractionation section C:

in the initial hydroconversion section A _1; and or

- in an additional hydroconversion section A, ·, and / or

in an intermediate separation section B _y .

The following embodiments are described with reference to the corresponding figures

Figure 1 schematically shows the general case of the method according to the invention, including different options corresponding to different embodiments.

According to the process illustrated in FIG. 1, the hydrocarbon heavy load 1 is sent via a pipe in an initial hydroconversion section Ai composed of one or more three-phase reactors, which can be in series and / or in parallel. These hydroconversion reactors may, in addition, be fixed-bed reactors, moving bed, bubbling bed, and / or hybrid bed, depending on the charge to be treated, and are preferably reactors operating as a bubbling bed. The initial hydroconversion step performed in section Ai represents the first hydroconversion step of the heavy hydrocarbon feedstock 1, and may include the co-treatment of one or more external feeds 2 and / or one or more effluents. recycle from other steps of the process.

The different recycling effluents that can be injected in section A- _\ are as follows:

a part of the total effluent (6, 10) from one or more additional hydroconversion sections A;

a part or all of one or more intermediate fractions originating from one or more intermediate separation sections B _j (not shown in FIG. 1);

a part of the heavy fraction resulting from one or more intermediate separation sections B _j ;

a part or all of one or more intermediate cuts 12 originating from the first fractionation section C;

a part of the heavy cut 13 resulting from the first fractionation section C;

a part or all of the residual asphalt 14 coming from the deasphalter D;

a part or all of the light fraction 16 of the DAO resulting from the second fractionation section E.

The liquid effluent 3 from the initial hydroconversion section A- ₁ may be sent either directly to the additional hydroconversion section A ₂ or to the intermediate separation section B- ₁ via a pipe. This pipe offers the possibility of purging a fraction of this effluent 3 and thus sending either all or only a part of the liquid effluent from A- ₁ to the intermediate separation section Bi.

Section B- ₁ represents the first intermediate separation section where the intermediate separation step (bi) is performed. It receives part or all of the liquid effluent from the previous hydroconversion stage A _1; possibly with a heavy hydrocarbon feed injection 1 and / or an injection of one or more external charges 2 and / or an injection of one or more recycling effluents. The different recycling effluents that can be injected in section Bi are:

a part of the total effluent (6, 10) from one or more additional hydroconversion sections A,;

a part or all of one or more intermediate fractions originating from one or more intermediate separation sections B _j (not shown in FIG. 1); a portion of the heavy fraction 9 resulting from one or more intermediate separation sections B _j downstream;

a part of the heavy cut 13 resulting from the first fractionation section C;

part or all of the DAO 15 from the deasphalter D;

a part or all of the light fraction of the DAO 16 resulting from the second fractionation section E;

a part or all of the heavy fraction of the DAO 17 resulting from the second fractionation section E.

The heavy fraction 5 resulting from the first intermediate separation section Bi is then sent at least partly to the additional hydroconversion section A ₂ via a pipe, while the light fraction 4 from the section B- ₁ is purged via a other conduct. A purge of the heavy fraction 5 can be carried out, it is either a part or the whole of the heavy fraction 5 which is sent to the additional hydroconversion section A ₂ . Part of the effluent 5 can also be recycled to the initial hydroconversion section Ai.

Section A ₂ represents the second hydroconversion section where an additional hydroconversion step (a ₂ ) is carried out. Section A ₂ is composed of one or more three-phase reactors, which can be in series and / or in parallel. These hydroconversion reactors may, in addition, be fixed-bed reactors, moving bed, bubbling bed, and / or hybrid bed, depending on the charge to be treated, and are preferably reactors operating as a bubbling bed.

This section A ₂ may receive part or all of the liquid effluent from the initial hydroconversion section i and / or at least a portion of the heavy fraction from the first intermediate separation section Bi. This section A ₂ can also receive for co-treatment part of the heavy hydrocarbon load 1 and / or one or more additional charges 2 and / or one or more recycling effluents. The various recycling effluents that can be injected into section A ₂ are:

a part of the total effluent of one or more additional hydroconversion sections A downstream; a part or all of one or more intermediate fractions coming from one or more intermediate separation sections B _j downstream (not shown in FIG. 1);

a portion of the heavy fraction 9 resulting from one or more intermediate separation sections B _j downstream;

a part of the heavy cut 13 resulting from the first fractionation section C;

part or all of the DAO 15 from the deasphalter D;

a part or all of the residual asphalt 14 coming from the deasphalter D;

a part or all of the heavy fraction 17 of the DAO resulting from the second fractionation section E.

The liquid effluent 6 issuing from the second hydroconversion section A ₂ may be sent to a third hydroconversion section, or to a second intermediate separation section via a pipe which offers the possibility of purging a fraction of said effluent and thus of send either all or only a portion of said effluent from section A ₂ to the second intermediate separation section B ₂ (not shown), as well as to recycle a portion of said effluent to one or more hydroconversion sections upstream of the section A ₂ or to the intermediate separation section Bi located between the sections - \ and A ₂ .

The method according to the invention can thus comprise n hydroconversion stages and (n-1) intermediate separation steps.

Section B _{j = n-1} represents the last intermediate separation section. It receives a part or all of the liquid effluent 7 from the previous hydroconversion stage A _{i = n-1} , and optionally a heavy hydrocarbon feed injection 1 and / or an injection of one or more external charges 2 and / or an injection of one or more recycling effluents. The different recycling effluents that can be injected into the section B _{i = n-1} are:

part of the effluent of the last hydroconversion section A _n ; a part or all of one or more intermediate cuts (12) issuing from the first fractionation section C;

a part of the heavy cut resulting from the first fractionation section C;

part or all of the DAO 15 from the deasphalter D;

Section A _n represents the last hydroconversion stage where the additional hydroconversion step (a _n ) is carried out. Section A _n is composed of one or more three-phase reactors, which can be in series and / or in parallel. These hydroconversion reactors may, in addition, be fixed-bed reactors, moving bed, bubbling bed, and / or hybrid bed, depending on the charge to be treated, and are preferably reactors operating as a bubbling bed.

This section A _n may receive part or all of the effluent of the preceding hydroconversion step A _n-1 and / or the heavy fraction of the previous intermediate separation section B _{j = n-1} . This section A _n can also receive for a co-treatment part of the heavy hydrocarbon load 1 and / or one or more external charges 2 and / or one or more recycling effluents. The different recycling effluents that can be injected into section A _n are:

a part of the heavy cut 13 coming out of the first fractionation section

C;

a part or all of the residual asphalt 14 coming from the deasphalter D;

part or all of the DAO 15 from the deasphalter D;

Section C represents the first fractionation section in which all or at least a portion of the hydroconverted liquid effluent 10 from the last section hydroconversion A _n is sent via a line to be split into multiple sections. By way of example, FIG. 1 shows three sections, a light section 11, which comes out of the process according to the invention and which is optionally sent to a post-treatment, an intermediate section 12 and a heavy section 13. The latter two cuts may be partially or totally sent to other processes and / or recycled to one or more hydroconversion stages of the process according to the invention and / or recycled to one or more intermediate separation sections of the process according to the invention.

The first fractionation section C can also receive, either at the inlet or between two different equipment components of this section C, a portion of the heavy hydrocarbon feedstock 1 and / or external feeds 2 and / or one of the following recycling effluents:

a part of the heavy fraction resulting from one or more intermediate separation steps B _y (not shown in FIG. 1);

a part of the liquid effluent of one or more hydroconversion stages (ai and a) (not shown in FIG. 1);

a part of the DAO 15 produced in the deasphalter D;

a part of the heavy fraction of the DAO 17 produced in the second fractionation section E;

a part or all of the light fraction 16 of the DAO produced in the second fractionation stage E.

Section D represents the deasphalter operating the deasphalting step (d) (SDA) in which the DAO 15 and the residual asphalt 14 are extracted from at least a portion of the heavy cut 13 from the first fractionation section C The deasphalter D can also receive part of the heavy hydrocarbon feed 1 and / or additional feeds 2 and / or one of the following recycling effluents:

a part of the heavy fraction resulting from one or more intermediate separation sections B) (not represented in FIG. 1);

a part of the liquid effluent resulting from the initial hydroconversion section i or from one or more additional hydroconversion sections A (not shown in FIG. 1);

The DAO produced in the deasphalter D may be sent, partly or totally, into the second fractionation section E, or recycled, in part or totally, to one or more of the additional hydroconversion sections A, and / or to one or more of the By intermediate separation sections.

Section E represents a second fractionation section of the process according to the invention in which the fractionation step (e) of all or at least part of the DAO is carried out in at least two sections. By way of example, the method illustrated in FIG. 1 shows two sections, a light section 16, which can leave the process according to the invention and / or be recycled in different sections of the process as previously described, and a heavy section 17. The latter may then be partially or completely recycled in one or more additional hydroconversion sections A and / or recycled on one or more intermediate separation sections B _y .

The light cut 16 may, for example, partly or wholly be used to produce heavy fuel oils, such as bunker fuels. The light cut 16 may also, in part or in all, be sent to a conversion step operating with a process selected from the group consisting of fixed bed hydrocracking, fluidized catalytic cracking, ebullated bed hydroconversion these processes may include prior hydrotreatment.

According to a preferred embodiment, part or all of the light section 16 of the DAO deasphalted fraction is subjected to fixed bed hydrocracking, in the presence of hydrogen, at an absolute pressure of between 5 MPa and 35 MPa, at a temperature advantageously between 300 and 500 ° C, a WH between 0.1 h ¹ and 5 h ¹ , and a quantity of hydrogen of between 100 Nm ³ / m ³ and 1000 Nm ³ / m ³ (normal cubic meters) (Nm ³ ) per cubic meter (m ³ ) of liquid charge), and in the presence of a catalyst containing at least one element of non-noble group VIII and at least one element of group VI B and comprising a support containing at least a zeolite.

According to another preferred embodiment, part or all of the light section 16 of the DAO deasphalted fraction is subjected to FCC fluidized catalytic cracking in the presence of a catalyst, preferably free of metals, comprising alumina, silica, silica-alumina, and preferably comprising at least one zeolite.

According to another preferred embodiment, part or all of the light section 16 of the DAO deasphalted fraction is subjected to a bubbling bed hydroconversion, carried out in the presence of hydrogen, at an absolute pressure of between 2 MPa and 35 MPa, at a temperature between 300 ° C and 550 ° C, a quantity of hydrogen between 50 Nm ³ / m ³ and 5000 Nm ³ / m ³ (normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of liquid load), a WH of between 0.1 h ¹ and 10 h ¹ and in the presence of a support-containing catalyst and at least one Group VIII metal selected from nickel and cobalt and at least one Group VIB metal selected from molybdenum and tungsten.

The dashed circuit 18 in FIG. 1 represents the multiple possible catalyst exchanges between the different hydroconversion stages, as well as the purging and addition of fresh and spent catalysts.

Four preferred implementations of the general scheme of FIG. 1 are illustrated in FIGS. 2 to 5 by limiting more and more the number of equipment and thus the investment costs.

FIG. 2 illustrates the invention in a preferred embodiment comprising the recycling of the heavy fraction of the DAO at the inlet of the last hydroconversion stage.

According to this implementation, the process comprises the following successive stages: the initial hydroconversion step (ai), the intermediate separation step (bi), a second hydroconversion step (a ₂ ) which is the only step additional hydroconversion, the first fractionation step (c), the deasphalting step (d) and the second fractionation step (e).

The heavy hydrocarbon feedstock 1 is sent via a pipe into the initial hydroconversion section A- ₁ at high hydrogen pressure 19. Section A- ₁ is identical to that described with reference to FIG.

The liquid effluent 3 from section A- _\ is separated in the intermediate separation section Bi. In the separation section Bi, the conditions are generally chosen so as to obtain two liquid fractions, a light fraction 4 and a heavy fraction 5. The section may comprise any separation means known to those skilled in the art, and preferably not has neither an atmospheric distillation column nor a vacuum distillation column, but a steam or hydrogen stripping column, and is more preferably constituted by a sequence of flash balls, and even more preferably by a only flash balloon.

The heavy liquid fraction 5 at the outlet of the intermediate separation section Bi is then sent via a pipe in the second hydroconversion stage A ₂ at high hydrogen pressure 20. This section A ₂ is in accordance with the description of the section d initial hydroconversion A- _\ Figure 1. The hydroconverted liquid effluent 6 obtained at the end of this second hydroconversion stage is separated in the first fractionation section C. In this section C, the conditions are chosen so as to obtain at least two liquid fractions, a light cut 11 and a heavy section 13. The section preferably comprises a set of flash balloons and an atmospheric distillation column.

The heavy cut 13 is then sent via a line into the deasphalter D to obtain a DAO 15 which is sent to the second fractionation section E via a line and a residual asphalt 14 which is purged via another line.

The DAO fraction is then separated in the second fractionation section E, where the conditions are chosen so as to obtain at least two liquid fractions, a light fraction of the DAO 16 and a heavy fraction of the DAO 17. The section E comprises preferably a set of flash balloons and a vacuum distillation column.

The heavy fraction of the DAO 17 is then mixed, in part or in full as shown, with the heavy liquid fraction 5 from the intermediate separation section Bi and the mixture is then sent to the second hydroconversion section A ₂ .

Figure 3 illustrates the invention in another implementation involving the recycling of CAD into the intermediate separation section.

According to this implementation, the process comprises the following successive stages: the initial hydroconversion step (ai), the intermediate separation step (bi), a second hydroconversion step (a ₂ ) which is the only step additional hydroconversion, the first fractionation step (c), and the deasphalting step (d). There is no second stage of splitting (e).

The heavy hydrocarbon feedstock is sent 1 via a conduit in an initial hydroconversion section A- _\ high hydrogen pressure section 19. A- _\ is the same as described in connection with Figure 1.

The liquid effluent 3 from the section Ai is separated in the intermediate separation section Bi at the same time as the recycled DAO 15 from the deasphalter D. In the intermediate separation section B ₁ the conditions are chosen so as to obtain two fractions The Bi section may comprise any separation means known to those skilled in the art, and preferably has no atmospheric distillation column or vacuum distillation column, but a column of stripping with steam or hydrogen, and is constituted more preferred by a sequence of flash balloons, and even more preferably by a single flash ball.

The heavy liquid fraction 5 at the outlet of the intermediate separation section Bi is then sent to the second hydroconversion section A ₂ at high hydrogen pressure 20. This section A ₂ is in accordance with the description of the initial hydroconversion section. A- _\ Figure 1.

The hydroconverted liquid effluent 6 obtained at the end of this second hydroconversion stage is separated in the first fractionation section C. In this section C, the conditions are chosen so as to obtain at least two liquid fractions, a light cut 11 and a heavy section 13. The section preferably comprises using a set of flash balloons and an atmospheric distillation column.

The heavy cut 13 is then sent via a line into the deasphalter D to obtain a DAO which is recycled to the intermediate separation section B- ₁ and a residual asphalt 14 which is purged via another conduit.

The DAO is then mixed, in part or in full as shown, with the liquid effluent 3 from the initial hydroconversion section A- ₁ and the mixture is then sent to the intermediate separation section Bi.

FIG. 4 illustrates the invention in another preferred embodiment including recycle of the DAO at the inlet of the last hydroconversion stage.

The heavy hydrocarbon feedstock 1 is sent via a pipe into an initial hydroconversion section Ai at high hydrogen pressure 19. The section Ai is identical to that described with reference to FIG.

The liquid effluent 3 from the section Ai is separated in the intermediate separation section Bi. In the separation section B ₁ the conditions are chosen so as to obtain two liquid fractions, a light fraction 4 and a heavy fraction 5. The section may comprise any separation means known to those skilled in the art, and preferably does not comprise no atmospheric distillation column or vacuum distillation column, but a steam or hydrogen stripping column, and is more preferred by a sequence of flash balloons, and even more preferably by a single flash ball.

The heavy liquid fraction 5 at the outlet of the intermediate separation section Bi is then sent via a pipe in the second hydroconversion stage A ₂ at high hydrogen pressure 20. This section A ₂ is in accordance with the description of the section d initial hydroconversion A- _\ Figure 1.

The hydroconverted liquid effluent 6 obtained at the end of this second hydroconversion stage is separated in the first fractionation section C. In this section C, the conditions are chosen so as to obtain at least two liquid fractions, a light cut 11 and a heavy section 13. The section preferably comprises a set of flash balloons and atmospheric and vacuum distillation columns.

The heavy cut 13 is then sent via a line into the deasphalter D to obtain a DAO 15 which is recycled via a line to the second hydroconversion section A ₂ and a residual asphalt 14 which is purged via another line.

The DAO is then mixed, in part or in full as shown, with the heavy liquid fraction 5 from the intermediate separation section B- ₁ and the mixture is then sent to the second hydroconversion section A ₂ .

FIG. 5 illustrates the invention in another implementation that does not include an intermediate separation step.

According to this implementation, the process comprises the following successive stages: the initial hydroconversion stage (ai), a second hydroconversion stage (a ₂ ) which is the only additional hydroconversion stage, the first stage of fractionation (c), and the deasphalting step (d). There is no second stage of splitting (e).

The liquid effluent 3 from the section Ai is then sent via a pipe into the second hydroconversion section A ₂ at high hydrogen pressure 20. This section A ₂ is in accordance with the description of the initial hydroconversion section Ai of Figure 1.

The hydroconverted liquid effluent 6 obtained at the end of this second hydroconversion stage is separated in the first fractionation section C. In this section C, the conditions are chosen so as to obtain at least two liquid fractions, a light section 11 and a heavy section 13. The section preferably comprises using a set of flash balloons and atmospheric distillation columns and vacuum.

The heavy cut 13 is then sent via a line into the deasphalter D to obtain the DAO 15 which is recycled via a pipe to the second hydroconversion section A ₂ and a residual asphalt 14 which is purged via another pipe.

The DAO 15 is mixed, in part or in full as shown, with the liquid effluent 3 from the initial hydroconversion section Ai, and the mixture is sent to the second hydroconversion section A ₂ . Examples

The following examples illustrate an example of implementation of the method according to the invention, without limiting the scope, and some of its performance, in comparison with methods according to the prior art.

Examples 1, 2 and 6 are not in accordance with the invention. Examples 3, 4, 5 and 7 are in accordance with the invention.

Charge

The hydrocarbon heavy load is a vacuum residue (RSV) from an Ural crude oil whose main characteristics are shown in Table 2 below.

Table 2

This RSV heavy load is the same fresh load for the different examples. Example 7 Method of. reference without _, recycling _, of. the. DAO .. (n.on .. conform to l.'inyentipn)

This example illustrates a hydroconversion process for a heavy hydrocarbon feedstock according to the state of the art comprising two successive hydroconversion stages, each comprising a reactor operating as a bubbling bed, followed by a step of deasphalting without recycle. the DAO.

P. hydroconversion

The fresh feed of Table 2 is sent wholly in a first hydroconversion section A'i in the presence of hydrogen to undergo a first hydroconversion step (a'-i), said section comprising a three-phase reactor containing a catalyst. NiMo / alumina hydroconversion having a NiO content of 4% by weight and a MoO ₃ content of 10% by weight, the percentages being expressed relative to the total mass of the catalyst. The reactor operates in a bubbling bed operating at an upward flow of liquid and gas.

The operating conditions applied in the first hydroconversion stage are shown in Table 3 below.

Table 3

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The conversion of the 540 ° C + fraction at the outlet of the first hydroconversion stage is 42.0% by weight.

Intermediate Separation Stage.

The hydroconverted liquid effluent from the first hydroconversion stage (a'-i) is then sent to an intermediate separation section B'-i composed of a single gas / liquid separator operating at the reactor pressure and temperature. of the first hydroconversion stage. A light fraction and a so-called heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point below 350 ° C and the heavy fraction is mainly composed of hydrocarbon molecules boiling at a temperature greater than or equal to 350 ° C. The composition of this heavy fraction is shown in Table 4.

Table 4

Second hydroconversion stage {a ₂ J _:

The heavy fraction, the composition of which is given in Table 4, is sent to a second hydroconversion section A ' ₂ in the presence of hydrogen to undergo a second hydroconversion stage (a' ₂ ).

The second hydroconversion section A ' ₂ comprises a triphasic reactor A' ₂ containing a NiMo / alumina hydroconversion catalyst having a NiO content of 4% by weight and a MoO ₃ content of 10% by weight, the percentages being expressed by relative to the total mass of the catalyst. The section operates as a bubbling bed operating with an upward flow of liquid and gas.

The operating conditions applied in the second hydroconversion stage (a ' ₂ ) are shown in Table 5 below.

Table 5

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The conversion of the fraction 540 ° C + produced during this second hydroconversion stage is 38.1% by weight.

First step of jetting

The hydroconverted liquid effluent resulting from the hydroconversion stage (a ' ₂ ) is sent to a fractionation stage (c') carried out in a fractionation section C 'composed of an atmospheric distillation column and a distillation column under vacuum after which a vacuum distillate fraction boiling at a temperature of essentially between 350 ° C and 500 ° C (DSV) and a fraction unconverted vacuum residue boiling at a temperature greater than or equal to 500 ° C (RSV) whose yields relative to the fresh charge and qualities of products are given in Table 6 below.

Table 6

Deasphalting step

The RSV from the distillation zone of the fractionation section C 'is then advantageously sent to a deasphalting step (cT) in a deasphalter D' in which it is treated in an extractor using the butane solvent under conditions deasphalting to obtain a DAO and a residual asphalt.

The operating conditions applied in the deasphalter are as follows:

Total pressure = 3 MPa;

Average temperature = 95 ° C;

Solvent ratio / charge = 8 v / v.

At the deasphalter outlet, a DAO and a residual asphalt having the characteristics given in Table 7 below are obtained.

Table 7 Overall performance

With this conventional process, not in accordance with the invention, the overall conversion of the 540 ° C + fraction of the fresh feed is 64.0% by weight. The unconverted vacuum residue fraction contains 0.20% by weight of sediment, 150 ppm by weight of metals and a Conradson carbon content of greater than 30% by weight. This cut is therefore very difficult to valorize. The deasphalting of the unconverted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents almost 70% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 8% by weight. This CAD cut can therefore be sent, in part or in full, in another conversion step such as fixed bed hydrocracking, fixed bed hydrotreatment, fluidized catalytic cracking, or bubbling bed hydroconversion. .

E ernp / e 2 _; Process ". this reference with. recycling. of. / DAO at the entrance. from Ja first _, step. of hydrgconyersjpn (no _, according to the invention)

In this example 2, the state of the art is illustrated in a hydroconversion process of a heavy hydrocarbon feedstock comprising two successive hydroconversion stages, each comprising a reactor operating as a bubbling bed, followed by a step of deasphalting with recycling of the DAO at the entrance of the first hydroconversion stage.

Pre-stage hydroconversion

The fresh feed of Table 2 is first mixed with the DAO resulting from the deasphalting step (d ") in a ratio by fresh feed / DAO equal to 75/25. This mixture is then sent entirely into a first hydroconversion section A " _! in the presence of hydrogen to undergo a first hydroconversion step (a " _! ). This section A " _! is identical to that described in Example 1.

The conditions applied in this first hydroconversion section A " _! are shown in Table 8 below.

Table 8

The increase of the WH reactor, compared to the WH during the first hydroconversion step according to Example 1, is due to the recycling of the DAO, the fresh feed rate being kept constant. These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The pass conversion of the 540 ° C + fraction at the outlet of the first hydroconversion stage is 33.4% by weight.

Intermediate Separation Stage.

The hydroconverted liquid effluent from the first hydroconversion stage (a "i) is then sent to an intermediate separation section B" _! composed of a single gas / liquid separator operating at the pressure and the reactor temperature of the first hydroconversion stage. A light fraction and a heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point of less than 350 ° C. and the so-called heavy fraction is mainly composed of hydrocarbon molecules bubbling at a temperature greater than or equal to 350 ° C.

The composition of this heavy fraction is shown in Table 9.

Table 9

Second hydroconversion stage

The heavy fraction, the composition of which is given in Table 9, is wholly sent to a second hydroconversion section A " ₂ in the presence of hydrogen to undergo a second hydroconversion step (a" ₂ ). This section A " ₂ is identical to that described in Example 1. The operating conditions applied during this second hydroconversion stage (a " ₂ ) are presented in Table 10 below.

Table 10

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The pass conversion of the 540 ° C + fraction carried out during this second hydroconversion stage is 33.7% by weight.

First step of ractjonnement

The hydroconverted liquid effluent of the hydroconversion stage (a " ₂ ) is sent a fractionation step (c") carried out in a fractionation section C "composed of an atmospheric distillation column and a distillation column under vacuum, after which a vacuum distillate fraction boiling at a temperature essentially between 350 ° C. and 500 ° C. (DSV) and an unconverted vacuum residue fraction boiling predominantly at a temperature greater than or equal to 500 ° C. is recovered. (RSV) whose yields with respect to the fresh load and qualities of products are given in Table 11 below.

Table 11

Deasphalting step

The RSV from the first fractionation section C "is then advantageously sent to a deasphalting step (d") in a deasphalter D ", in which it is treated as described in Example 1 (same equipment and same conditions). At the deasphalter outlet, a DAO and a residual asphalt having the characteristics given in Table 12 below are obtained.

Table 12

After deasphalter D, 26% of the produced DAO is purged, while the rest of the DAO is sent upstream of the first hydroconversion stage (a " _! ).

Overall performance

With this conventional method comprising a recycling of the DAO at the inlet of the first hydroconversion step, not in accordance with the invention, the pass conversion of the fraction 540 ° C + of the fresh charge in the section of hydroconversion is 55.9% weight. The unconverted vacuum residue fraction contains 0.34% sediment weight, 74 ppm metal weight and a Conradson carbon content of 21% by weight. This cut is therefore very difficult to valorize. The deasphalting of the unconverted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents almost 74% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 5% by weight. In this scheme not in accordance with the invention, a large fraction of this CAD cut (74%) is recycled to the inlet of the first reactor of the hydroconverison section. Thanks to recycling, the overall conversion of the 540 ° C + fraction of the fresh feed is 69.7% by weight.

Exempje.3; Process ". seJonJ'myention to reduce _the _ta, sediment content of the _residue, _under, vjde ngn-con verti

In this example, the process according to the invention is illustrated in an implementation comprising two successive hydroconversion stages each comprising a reactor operating in a bubbling bed followed by a deasphalting step with recycling of the DAO at the inlet of the last hydroconversion reactor.

First step dihydro version.

Fresh feed of Table 2 is sent in full in a first section hydroconversion A- _\ in the presence of hydrogen to undergo a first hydroconversion step (I). This section A- _\ is identical to that described in Example 1.

The operating conditions applied to this first hydroconversion stage (ai) are presented in Table 13 below.

Table 13

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The conversion of the fraction 540 ° C + produced during this first hydroconversion stage is 42% by weight.

Intermediate separation step

The hydroconverted liquid effluent is then sent to an intermediate separation section B-i composed of a single gas / liquid separator operating at the pressure and the reactor temperature of the first hydroconversion stage. A light fraction and a heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point of less than 350 ° C. and the so-called heavy fraction is mainly composed of hydrocarbon molecules bubbling at a temperature greater than or equal to 350 ° C.

The composition of this heavy fraction is shown in Table 14.

Table 14 _Second, _step hydroconversion

In this example of the process according to the invention, the heavy effluent from the intermediate separation section Bi is mixed in all with the DAO resulting from the deasphalting step (d) in a volume ratio of heavy effluent / DAO of 75 / 25. The composition of this charge is shown in Table 15.

Table 15

In this example according to the invention, this mixture is sent entirely into a second hydroconversion section A ₂ in the presence of hydrogen to undergo a second hydroconversion step (a ₂ ). Said section A ₂ is identical to that described in Example 1.

The operating conditions applied in the hydroconversion step (a ₂ ) are shown in Table 16 below.

Table 16

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The pass conversion of the 540 ° C + fraction carried out during this second hydroconversion stage is 33.0% by weight.

First _, section. splitting

The hydroconverted liquid effluent resulting from the hydroconversion step (a ₂ ) is sent to a fractionation step (c) carried out in a fractionation section C composed of an atmospheric distillation column and a vacuum distillation column at the from which a vacuum distillate fraction boiling at a temperature of essentially 350 ° C to 500 ° C (DSV) and an unconverted vacuum residue fraction boiling at a temperature of 500 ° C (RSV) or higher is recovered. Returns relative to the fresh load and grades of products are given from this first fractionation section are shown in Table 17 below.

Table 17

Comparing with Example 1, there is a higher level of hydrotreatment with lower density, lower levels of sulfur, nitrogen, metals, asphaltenes and Conradson carbon. In addition, the RSV contains less sediment and is therefore more stable, particularly thanks to the presence of heavy aromatics recycled DAO upstream of the second hydroconversion stage.

Comparing with Example 2, it is noted that the level of hydrotreatment is slightly lower, but the RSV contains much less sediment. This cut is thus more stable, in particular thanks to the presence of heavy aromatics of the recycled CAD cut upstream of the second hydroconversion stage. In Example 2, the DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are further hydrogenated compared to the process according to the invention.

Deasphalting step

The RSV from the first fractionation section is then advantageously sent to a deasphalting step (d) in a deasphalter, in which it is treated as described in Example 1 (same equipment and same conditions).

On leaving the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 18 below are obtained.

Table 18

After deasphalter D, 26% of the produced DAO is purged, while the rest of the DAO is sent upstream of the second hydroconversion stage. Overall performance

According to the method of the invention illustrated in this example, comprising a recycle of the DAO at the last hydroconversion stage, the pass conversion of the 540 ° C + fraction of the fresh charge of the hydroconversion section is 61.5% wt. The unconverted vacuum residue fraction contains 0.07% sediment weight, 63 ppm metal weight and a Conradson carbon content of 24% weight. This cut is therefore very difficult to valorize. The deasphalting of the unconverted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents almost 74% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 5% by weight. In this scheme according to the invention, a large fraction of this CAD cut (74%) is recycled at the inlet of the last reactor of the hydroconverison section. Thanks to recycling, the overall conversion of the 540 ° C + fraction of the fresh feed is 69.5% by weight.

It should therefore be noted that, compared with Example 1, the conversion is higher (5.5 conversion points in addition) and that the RSV leaving the vacuum distillation column at the first fractionation stage is more stable. (0.07% by weight instead of 0.20% by weight) because it contains less sediment, thus limiting the fouling of the columns of the first fractionation section. Compared to Example 2, the overall conversion is identical, but the residual RSV contains 5 times less sediment (0.07% by weight instead of 0.34% by weight). As a result, the fouling of the columns of the first fractionation section is greatly reduced allowing a longer operation before stopping for cleaning.

In this example, the process according to the invention is illustrated in an implementation comprising two successive hydroconversion stages each comprising a reactor operating as a bubbling bed followed by a deasphalting step with recycle of the DAO at the inlet of the last hydroconversion reactor. As the sediment content is reduced in the process according to the invention, the latter reactor will be operated under more severe conditions in order to increase the overall conversion of the process.

First hydroconversion stage

The fresh feed of Table 2 is sent entirely in a first hydroconversion section Ai in the presence of hydrogen to undergo a first hydroconversion step (a-i). This section Ai is identical to that described in Example 1.

The operating conditions applied to this first hydroconversion stage (ai) are presented in Table 19 below.

Table 19

Floor .separation .intermediate

The hydroconverted liquid effluent is then sent to an intermediate separation section Bi composed of a single gas / liquid separator operating at the pressure and the reactor temperature of the first hydroconversion stage. A light fraction and a heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point of less than 350 ° C. and the so-called heavy fraction is mainly composed of hydrocarbon molecules bubbling at a temperature greater than or equal to 350 ° C.

The composition of this heavy fraction is shown in Table 20.

Table 20

Second stage of hydroconversion.

In this example of the process according to the invention, the heavy effluent from the intermediate separation section Bi is mixed in all with the DAO resulting from the deasphalting step (d) in a volume ratio of heavy effluent / DAO of 75 / 25. The composition of this charge is shown in Table 21.

Table 21

The operating conditions applied in the hydroconversion step (a ₂ ) are presented in Table 22 below. Compared with the other examples, the reaction temperature was increased by 5 ° C.

Table 22

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The conversion by pass of the fraction 540 ° C + achieved during this second hydroconversion stage is 38.4% by weight.

P _iewé . é.ÇÉQD. splitting dp

The hydroconverted liquid effluent resulting from the hydroconversion step (a ₂ ) is sent to a fractionation step (c) carried out in a fractionation section C composed of an atmospheric distillation column and a vacuum distillation column at the from which a vacuum distillate fraction boiling at a temperature of essentially 350 ° C to 500 ° C (DSV) and an unconverted vacuum residue fraction boiling at a temperature of 500 ° C (RSV) or higher is recovered. The yields relative to the fresh feed and grades of products are given in this first fractionation section are shown in Table 23 below.

Table 23

Comparing with Example 1, there is a higher level of hydrotreatment with lower density, lower levels of sulfur, nitrogen, metals, asphaltenes and Conradson carbon. Despite the higher severity, the RSV contains the same sediment content and therefore remains stable, notably thanks to the presence of heavy aromatics from the recycled DAO upstream of the second hydroconversion stage.

Comparing with Example 2, it is noted that the level of hydrotreatment is very similar, but that the RSV contains less sediment. This cut is thus more stable, in particular thanks to the presence of heavy aromatics of the recycled CAD cut upstream of the second hydroconversion stage. In Example 2, the DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are further hydrogenated compared to the process according to the invention.

Deasphalting step

The RSV from the first fractionation section is then advantageously sent to a deasphalting step (d) in a deasphalter, in which it is treated as described in Example 1 (same equipment and same conditions). On leaving the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 24 below are obtained.

Table 24

After deasphalter D, 17% of the produced DAO is purged, while the rest of the DAO is sent upstream of the last hydroconversion stage.

Overall performance

According to the process of the invention illustrated in this example, comprising a recycle of the DAO in the last hydroconversion stage operated under more severe conditions, a pass conversion of the fraction 540 ° C + of the fresh feed of 64 is achieved. , 6% weight in the hydroconversion section for identical operating conditions. The unconverted fraction, the vacuum residue, contains 0.19% sediment weight, 61 ppm metal weight and a Conradson carbon content of 27% by weight. This cut is therefore very difficult to valorize. The deasphalting of the unconverted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents almost 73% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 6% by weight. In this scheme according to the invention, a large fraction of this CAD cut (83%) is recycled at the inlet of the last reactor of the hydroconverison section. Thanks to recycling, the overall conversion of the 540 ° C + fraction of the fresh feed is 73.9% by weight.

It is therefore noted that, compared with Example 1, the conversion is much higher (+10 conversion points), but that the RSV which leaves the vacuum distillation column at the first fractionation stage remains stable because it contains about the same sediment content (0.19% by weight instead of 0.20% by weight). Compared to Example 2, the conversion is larger (+4 conversion points), but the residual RSV still contains much less sediment (0.19% weight instead of 0.34% weight) and remains therefore stable under these more severe conditions. Therefore, in the diagram according to the invention, the fouling of the columns of the first fractionation section is greatly reduced compared to diagram 2 not in accordance with the invention, allowing a longer operation before stopping for cleaning.

Example 5 Polder according to invention _J to recycle the cut DAOjusgu' extinction

In this example, the process according to the invention is illustrated in an implementation comprising two successive hydroconversion stages each comprising a reactor operating as a bubbling bed followed by a deasphalting step with recycle of the DAO at the inlet of the last hydroconversion reactor. The CAD cut will be recycled to extinction to increase overall process conversion.

First step of the right

The operating conditions applied to this first hydroconversion stage (ai) are presented in Table 25Table 19 below.

Table 25

Intermediate Separation Stage.

The hydroconverted liquid effluent is then sent to an intermediate separation section Bi composed of a single gas / liquid separator operating at the pressure and the reactor temperature of the first hydroconversion stage. A light fraction and a heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point of less than 350 ° C. and the so-called heavy fraction is mainly composed of hydrocarbon molecules bubbling at a temperature greater than or equal to 350 ° C. The composition of this heavy fraction is presented in Table 26.

Table 26

Second stage of hydroconversion.

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B-i is mixed in all with the entire DAO cut resulting from the deasphalting step (d). The composition of this load is presented in Table 27.

Table 27

The operating conditions applied in the hydroconversion step (a ₂ ) are shown in Table 28 below. As the recycling of the CAD cut is total, the WH _reactor is larger.

Table 28

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The conversion by pass of the fraction 540 ° C + achieved during this second hydroconversion stage is 36.2% by weight.

Pre Island section. splitting

The hydroconverted liquid effluent resulting from the hydroconversion step (a ₂ ) is sent to a fractionation step (c) carried out in a fractionation section C composed of an atmospheric distillation column and a vacuum distillation column at the from which a vacuum distillate fraction boiling at a temperature of essentially 350 ° C to 500 ° C (DSV) and an unconverted vacuum residue fraction boiling at a temperature of 500 ° C (RSV) or higher is recovered. The yields relative to the fresh feed and grades of products are given in this first fractionation section are shown in Table 29 below.

Table 29

Comparing with Example 1, there is a higher level of hydrotreatment with lower density, lower levels of sulfur, nitrogen, metals, asphaltenes and Conradson carbon. Despite the higher severity, the RSV contains a similar sediment content (0.25% by weight relative to 0.20% by weight in Example 1) and thus remains stable, in particular thanks to the presence of heavy aromatics of the DAO recycled upstream of the second hydroconversion stage.

Comparing with Example 2, it is noted that the level of hydrotreatment is very similar, but that the RSV contains less sediment. This cut is thus more stable, in particular thanks to the presence of heavy aromatics of the recycled CAD cut upstream of the second hydroconversion stage. In Example 2, the DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are further hydrogenated compared to the process according to the invention. Deasphalting step

On leaving the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 30 below are obtained.

Table 30

After deasphalter D, the CAD cut is sent in full upstream of the last hydroconversion stage.

Overall performance

According to the process of the invention illustrated in this example, comprising a recycle of the DAO in the last hydroconversion stage operated under more severe conditions, a pass conversion of the fraction 540 ° C + of the fresh feed of 64 is achieved. , 6% weight in the hydroconversion section for identical operating conditions. The unconverted fraction, the vacuum residue, contains 0.25% sediment weight, 66 ppm metal weight and a Conradson carbon content of 25% by weight. This cut is therefore very difficult to valorize. The deasphalting of the non-converted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents 73.3% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is only 5.2% by weight. In this scheme according to the invention, all of this CAD cut is recycled to the inlet of the last reactor of the hydroconverison section. Thanks to the extinction recycling of the DAO cut, the overall conversion of the 540 ° C + fraction of the fresh feed is 76.1% by weight.

It should therefore be noted that, compared with Example 1, the conversion is much higher (+12 conversion points), but that the RSV that leaves the vacuum distillation column at the first fractionation stage remains stable because it contains about the same sediment content (0.25% by weight instead of 0.20% by weight). Compared to Example 2, the conversion is larger (more than 6 additional conversion points), but the residual RSV contains less sediment (0.25% by weight instead of 0.34% by weight) and therefore remains stable under these more severe conditions. Therefore, in the scheme according to the invention, the fouling of the columns of the first fractionation section is greatly reduced compared to diagram 2 not in accordance with the invention, allowing a longer operation before shutdown for their cleaning. .

In this example, the process according to the invention is illustrated in an implementation comprising two successive hydroconversion stages each comprising a reactor operating as a bubbling bed followed by a deasphalting step and a fractionation step, with recycling of the heavy DAO at the inlet of the last hydroconversion reactor and conversion of the light DAO into an FCC unit.

Pr.mjere e.tap.e.of.dhy.droconyersi.on

The operating conditions applied to this first hydroconversion step (ai) are presented in Table 31 below.

Table 31

Intermediate Separation Stage.

The composition of this heavy fraction is shown in Table 32.

Table 32

_Second, _step hydroconversion

In this example of the process according to the invention, the heavy effluent resulting from the intermediate separation section Bi is mixed in all with the heavy DAO resulting from the second fractionation section (e) in a heavy effluent / DAO volume ratio of 75. / 25. The composition of this charge is shown in Table 33.

Table 33

The operating conditions applied in the hydroconversion step (a ₂ ) are shown in Table 34 below.

Table 34

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The pass conversion of the fraction 540 ° C + achieved during this second hydroconversion stage is 32.0% by weight.

PfJsmjere fractionation area

The hydroconverted liquid effluent resulting from the hydroconversion step (a ₂ ) is sent to a fractionation step (c) carried out in a fractionation section C composed of an atmospheric distillation column and a vacuum distillation column at the from which a vacuum distillate fraction boiling at a temperature of essentially 350 ° C to 500 ° C (DSV) and an unconverted vacuum residue fraction boiling at a temperature of 500 ° C (RSV) or higher is recovered. The yields relative to the fresh load and grades of products are given in this first fractionation section are shown in Table 35 below.

Table 35

Comparing with Example 2, it is noted that the level of hydrotreatment is lower, but the RSV contains much less sediment. This cup is more stable, in particular thanks to the presence of heavy aromatics from the heavy recycled CAD cut upstream of the second hydroconversion stage. In Example 2, the total DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are further hydrogenated compared to the process according to the invention.

Deasphalting step

At the deasphalter outlet, a DAO and a residual asphalt having the characteristics given in Table 36 below are obtained.

Table 36

Second _, section. splitting

After deasphalter D, the produced CAD cut is sent to a second fractionation section (e) made in a fractionation section E composed of a series of flashes, an atmospheric distillation column and a vacuum distillation column after which a light DAO cut (DAO-) boiling at a temperature substantially below 580 ° C is recovered and a heavy DAO (DAO +) cut predominantly boiling at a temperature greater than or equal to 580 ° C. The characteristics of the light CAD and heavy CAD cut are given in Table 37 below.

Table 37

The heavy DAO cut (DAO +) from the fraction step (e) is sent entirely to the second hydroconversion stage, while the light DAO fraction (DAO-) is sent to an FCC catalytic cracking unit for additional conversion.

Conversion step in an FCC unit

The light DAO cut (DAO-) from the second fractionation section (e) made in the fractionation section E is then sent to a fluidized catalytic cracking unit, also called FCC. This conversion unit makes it possible to transform the DAO fraction, which is a 540 ° C + cut, into lighter fractions. This therefore makes it possible to increase the overall conversion of the feedstock. In contrast, the liquid fraction from the FCC unit still contains an unconverted 540 ° C + fraction with a yield of only 0.4% by weight relative to the FCC charge, as shown in Table 38.

Table 38

Overall performance

According to the process according to the invention illustrated in this example, comprising a recycle of the DAO at the last hydroconversion stage, the pass conversion of the 540 ° C + fraction of the fresh charge of the hydroconversion section is 60.9% weight. The unconverted vacuum residue fraction contains 0.12% by weight of sediment,

67 ppm weight of metals and a Conradson Carbon content of 28% by weight. This cut is therefore very difficult to valorize. Deasphalting of the unconverted vacuum residue allows extracting a valuable fraction by separating the RSV into a DAO fraction (which represents about 72% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 6% by weight. In this scheme according to the invention, the DAO cut is sent to a second fractionation section to produce a light DAO cut, which is sent to an FCC catalytic cracking unit for further conversion, and a heavy DAO cut, which is recycled in its entirety at the entrance of the last hydroconversion stage. Thanks to the recycling of the heavy DAO cut, the overall conversion of the 540 ° C + fraction of the fresh feed is 73.4% by weight in the hydrotreatment section. Thanks to the conversion of the light DAO into the FCC unit, an additional conversion of 4.1% by weight is obtained, resulting in an overall conversion of the scheme according to the invention of 77.5% by weight of the fraction 540 ° C. the fresh charge.

It is therefore noted that, compared with Example 1, the conversion is much higher (+13.5 conversion points), while keeping a stable RSV that leaves the vacuum distillation column at the first fractionation section. because it contains less sediment (0.12% by weight instead of 0.20% by weight), thus limiting the fouling of the columns of the first fractionation section. Compared to Example 2, the conversion is not only larger (almost 8 additional conversion points), but the residual RSV contains much less sediment (0.12% by weight instead of 0.34% by weight) and remains therefore stable under these more severe conditions. Therefore, in the diagram according to the invention, the fouling of the columns of the first fractionation section is greatly reduced compared to the scheme of Example 2 not in accordance with the invention, allowing a longer operation before the stop for cleaning. Compared to Example 3, the use of an FCC unit for conversion of the light CAD cut produces more gasoline and less diesel.

. con version

In this example, the process according to the invention is illustrated in an implementation comprising two successive hydroconversion stages each comprising a reactor operating as a bubbling bed followed by a deasphalting step and a fractionation step, with recycling of the heavy DAO at the inlet of the last hydroconversion reactor and conversion of the light DAO into an FCC unit. As the content In sediment is reduced in the process according to the invention, the latter reactor will be operated under more stringent conditions to increase the overall conversion of the process.

First step dihydro version.

The fresh feed of Table 2 is sent entirely in a first hydroconversion section Ai in the presence of hydrogen to undergo a first hydroconversion step (ai). This section - _\ is identical to that described in Example 1.

The operating conditions applied to this first hydroconversion step (ai) are presented in Table 39 below.

Table 39

Intermediate separation step

The composition of this heavy fraction is shown in Table 40.

Table 40 _Second, _step hydroconversion

In this example of the process according to the invention, the heavy effluent resulting from the intermediate separation section Bi is mixed in all with the heavy DAO resulting from the second fractionation section (e) in a heavy effluent / DAO volume ratio of 75. / 25. The composition of this charge is shown in Table 41.

Table 41

The operating conditions applied in the hydroconversion step (a ₂ ) are shown in Table 42 below.

Table 42

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced Conradson carbon content, in metals and in sulfur. The pass conversion of the fraction 540 ° C + produced during this second hydroconversion stage is 38.4% by weight.

First _, section. splitting

The hydroconverted liquid effluent resulting from the hydroconversion step (a ₂ ) is sent to a fractionation step (c) carried out in a fractionation section C composed of an atmospheric distillation column and a vacuum distillation column at the from which a vacuum distillate fraction boiling at a temperature of essentially 350 ° C to 500 ° C (DSV) and an unconverted vacuum residue fraction boiling at a temperature of 500 ° C (RSV) or higher is recovered. Returns relative to the fresh load and grades of products are given this first fractionation section are shown in Table 43 below.

Table 43

Comparing with Example 2, it is noted that the level of hydrotreatment is lower, but the RSV contains less sediment. This cut is thus more stable, in particular thanks to the presence of heavy aromatics from the heavy recycled CAD cut upstream of the second hydroconversion stage. In Example 2, the total DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are further hydrogenated compared to the process according to the invention.

Deasphalting step

On leaving the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 44 below are obtained.

Table 44

Second section _ of_ splitting

After deasphalter D, the produced CAD cut is sent to a second fractionation section (e) made in a fractionation section E composed of a series of flashes, an atmospheric distillation column and a vacuum distillation column after which a light DAO cut (DAO-) boiling at a temperature substantially below 580 ° C is recovered and a heavy DAO (DAO +) cut predominantly boiling at a temperature greater than or equal to 580 ° C. The characteristics of the light CAD and heavy CAD cut are given in Table 45 below.

Table 45

i¾pe conversion in. a. FCC unit

The light DAO cut (DAO-) from the second fractionation section (e) made in the fractionation section E is then sent to a fluidized catalytic cracking unit, also called FCC. This conversion unit makes it possible to transform the DAO fraction, which is a 540 ° C + cut, into lighter fractions. This therefore allows to increase the overall conversion of the starting load. In contrast, the liquid fraction from the FCC unit still contains an unconverted 540 ° C + fraction with a yield of only 0.4% by weight relative to the FCC charge, as shown in Table 46.

Table 46

Overall performance

According to the process according to the invention illustrated in this example, comprising a recycle of the DAO at the last hydroconversion stage, the pass conversion of the 540 ° C + fraction of the fresh charge of the hydroconversion section is 64.6% weight. The unconverted vacuum residue fraction contains 0.23% sediment weight, 65 ppm metal weight and a Conradson carbon content of 29% weight. This cut is therefore very difficult to valorize. The deasphalting of the unconverted vacuum residue makes it possible to extract a valuable fraction by separating the RSV into a DAO fraction (which represents about 72% of the RSV) and an asphalt fraction. The DAO fraction contains almost no metals or asphaltenes and its Conradson Carbon content is less than 6% by weight. In this scheme according to the invention, the DAO cut is sent to a second fractionation section to produce a light DAO cut, which is sent to an FCC catalytic cracking unit for further conversion, and a heavy DAO cut, which is recycled in its entirety at the entrance of the last hydroconversion stage. Thanks to the recycling of the heavy DAO cut, the overall conversion of the 540 ° C + fraction of the fresh feed is 79.2% by weight in the hydrotreatment section. Thanks to the conversion of the light DAO into the FCC unit, an additional conversion of 4.0% by weight is obtained, resulting in an overall conversion of the scheme according to the invention of 83.2% by weight of the 540 ° C + fraction. the fresh charge.

It is therefore noted that, compared with Example 1, the conversion is much higher (+19 conversion points), while keeping a stable RSV which leaves the vacuum distillation column at the first fractionation section, because it has a similar sediment content (0.23% by weight instead of 0.20% by weight). Compared to Example 2, the conversion is not only larger (over 12 additional conversion points), but the Residual RSV contains less sediment (0.23% weight instead of 0.34% weight) and thus remains more stable despite the more severe conditions. Therefore, in the diagram according to the invention, the fouling of the columns of the first fractionation section is greatly reduced compared to the scheme of Example 2 not in accordance with the invention, allowing a longer operation before the stop for cleaning. Compared to Example 3, the use of an FCC unit for conversion of the light CAD cut produces more gasoline and less diesel.

Claims

A process for converting a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling point of at least 300 ° C, and containing sulfur, Conradson carbon, metals, and nitrogen, comprising the following successive steps:

an initial step of hydroconversion (ai) of at least a portion of said heavy hydrocarbon charge in the presence of hydrogen in an initial hydroconversion section (Ai), carried out under conditions making it possible to obtain a liquid effluent reduced sulfur, Conradson carbon, metals, and nitrogen;

- (n-1) additional hydroconversion stage (s) (a, ·) in (n-1) additional hydroconversion section (s) (A, ·), in the presence of hydrogen , at least part or all of the liquid effluent from the preceding hydroconversion stage (ar1) or optionally a heavy fraction from an optional intermediate separation step (b _y ) in a section intermediate separation (B _y ) between two consecutive hydroconversion stages separating some or all of the liquid effluent from the preceding hydroconversion stage (a) to produce at least one heavy fraction boiling predominantly at a higher temperature or equal to 350 ° C, the (n-1) additional hydroconversion stage (s) (a, ·) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur content, Conradson carbon, in metals, and nitrogen,

where n is the total number of hydroconversion steps, where n is greater than or equal to 2, where / is an integer from 2 to n and y is an integer from 1 to (n-1), and the hydroconversion sections initial (Ai) and additional (s) (A, ·) each comprising at least one triphasic reactor containing at least one hydroconversion catalyst;

a first fractionation step (c) in a first fractionation section (C) of part or all of the hydroconverted liquid effluent resulting from the last additional hydroconversion stage (a _n ) producing at least one cut heavy boiling predominantly at a temperature greater than or equal to 350 ° C, said heavy cup containing a residual fraction boiling at a temperature greater than or equal to 540 ° C;

a step of deasphalting (d) in a deasphalter (D) of part or all of said heavy cut resulting from the fractionation step (c), with at least one hydrocarbon solvent, to obtain a deasphalted oil DAO and residual asphalt; optionally a second fractionation step in a second fractionation section (E) of a part or all of the DAO resulting from the deasphalting step (d) into at least one heavy fraction of DAO and a light fraction of DAO;

a recycling step (f) of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a, ·) and / or an intermediate separation step (b _y ).

The process according to claim 1, wherein said heavy hydrocarbon feed has a sulfur content of at least 0.1% by weight, a Conradson carbon content of at least 0.5% by weight, an asphaltenes content. C ₇ at least 1% by weight, and a metal content of at least 20 ppm by weight.

A process according to any one of the preceding claims, wherein said hydrocarbon heavy load is a crude oil or consists of atmospheric residues and / or vacuum residues from atmospheric distillation and / or vacuum of a crude oil, and preferably consists of vacuum residues from the vacuum distillation of a crude oil.

4. Method according to any one of the preceding claims, wherein said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating in ebullated bed, with an upward flow of liquid and gas.

5. Method according to any one of the preceding claims, wherein said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating in a hybrid bed, said hybrid bed comprising at least one catalyst maintained in said triphasic reactor and at least a catalyst entrained out of said triphasic reactor.

6. Process according to any one of the preceding claims, in which the initial hydroconversion stage (ai) is carried out under an absolute pressure of between 2 and 38 MPa at a temperature of between 300 ° C. and 550 ° C. at a space velocity WH hour relative to the volume of each triphasic reactor between 0.05 h ¹ and 10 h ¹ and under a quantity of hydrogen mixed with the heavy hydrocarbon load of between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of heavy hydrocarbon load.

7. Process according to any one of the preceding claims, in which the additional hydroconversion stage or stages (a _n ) are carried out at a temperature of between 300 ° C. and 550 ° C., and greater than the temperature operated at initial hydroconversion step (ai), under a quantity of hydrogen mixed with the hydrocarbon heavy load of between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of heavy hydrocarbon charge, and less than the quantity of hydrogen operated at the initial hydroconversion stage (ai), at an absolute pressure of between 2 and 38 MPa, and at a space velocity WH of the volume of each triphasic reactor between 0.05 h ¹ and 10 h ¹ .

A method according to any one of the preceding claims, wherein the intermediate separation section (B _y ) comprises one or more flash balloons arranged in series, and / or one or more steam stripping columns and / or hydrogen, and / or an atmospheric distillation column, and / or a vacuum distillation column, and is preferably constituted by a single flash balloon.

A method according to any one of the preceding claims, wherein the first fractionation section (C) comprises one or more flash balloons arranged in series, and / or one or more steam stripping columns and / or hydrogen, and / or an atmospheric distillation column, and / or a vacuum distillation column, and is preferably constituted by a set of several flash balloons in series and atmospheric distillation columns and under vacuum.

A method as claimed in any one of the preceding claims, wherein the second fractionation section (E) comprises one or more flash balloons arranged in series, and / or one or more steam stripping columns and / or hydrogen, and / or an atmospheric distillation column, and / or a vacuum distillation column, and is preferably constituted by a set of several flash balloons in series and a vacuum distillation column.

11. Process according to any one of the preceding claims, in which the deasphalting step (d) is carried out in an extraction column at a temperature of between 60 ° C. and 250 ° C. with at least one hydrocarbon solvent having 3 to 7 carbon atoms, and a solvent / filler ratio (volume / volume) of between 3/1 and 16/1, and preferably between 4/1 and 8/1.

12. A method according to any one of the preceding claims, wherein a portion of the hydrocarbon heavy load is sent to at least one additional hydroconversion section (A, ·) and / or in at least one intermediate separation section. (B _y ) and / or in the first fractionation section (C) and / or in the deasphalter (D).

A process according to any one of the preceding claims, wherein an external hydrocarbon feed is fed to the process in the initial hydroconversion section (A 1) and / or in at least one additional hydroconversion section (A, · ) and / or in at least one intermediate separation section (B _y ) and / or in the first fractionation section (C) and / or in the deasphalter (D).

The method of any one of the preceding claims, further comprising at least one subsequent recycling step:

recycling (n) a portion or all of the light fraction of the DAO resulting from step (e) in the initial hydroconversion section (Ai) and / or in at least one hydroconversion section additional (A, ·) and / or in at least one intermediate separation section (B _y ) and / or in the first fractionation section (C);

recycling (r ₂ ) a portion of the heavy fraction of the DAO resulting from step (f) into the first fractionation section (C);

recycling (r ₃ ) a portion of the DAO resulting from step (d) into the first fractionation section (C);

recycling (r ₄ ) of part or all of the residual asphalt resulting from step (d) in the initial hydroconversion section (Ai) and / or in at least one additional hydroconversion section (AT,·) ;

recycling (r ₅ ) of a part of the hydroconverted liquid effluent of a given additional hydroconversion section (A, ·):

- in the initial hydroconversion section (Ai), and / or

- in another additional hydroconversion section (A, ·) positioned upstream of said given section (A, ·), and / or

in an intermediate separation section (B _y ) positioned upstream of said given section (A, ·); recycling (r ₆ ) of a part of the heavy fraction and / or of part or all of one or more intermediate fractions resulting from a given intermediate section (B _y ):

- in the initial hydroconversion section (A-i), and / or

in an additional hydroconversion section (A, ·) positioned upstream of said given intermediate section (B _y ), and / or

in another intermediate separation section (B _y ) positioned upstream of said given section (B _y );

recycling (r ₇ ) a part of the heavy fraction and / or a part or all of one or more intermediate fractions resulting from the first fractionation section (C):

- in the initial hydroconversion section (A-i), and / or

- in an additional hydroconversion section (A, ·), and / or

in an intermediate separation section (B _y ).

15. Conversion method according to any one of the preceding claims, wherein n is equal to 2, and comprising the following successive steps:

an additional hydroconversion stage (a ₂ ) in an additional hydroconversion section (A ₂ ), in the presence of hydrogen, of at least part or all of the liquid effluent resulting from the step of initial hydroconversion _(a}) or optionally a heavy fraction that an optional intermediate separation stage _(b}) in an intermediate separation section (B) between the stages of initial hydroconversion _(a}) and additional ( a ₂ ) separating part or all of the liquid effluent resulting from the initial hydroconversion step (a ₎ ) into at least one light fraction boiling predominantly at a temperature below 350 ° C and at least one heavy boiling fraction predominantly at a temperature greater than or equal to 350 ° C, the additional hydroconversion step (a ₂ ) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur content, Conradson carbon, in methanol. x, and nitrogen,

the initial (Ai) and additional (A ₂ ) hydroconversion sections each comprising at least one triphasic reactor containing at least one hydroconversion catalyst; a first fractionation step (c) in a first fractionation section (C) of part or all of the hydroconverted liquid effluent resulting from the additional hydroconversion stage (a ₂ ) producing at least one cut heavy boiling predominantly at a temperature greater than or equal to 350 ° C, said heavy cup containing a residual fraction boiling at a temperature greater than or equal to 540 ° C;

a step of deasphalting (d) in a deasphalter (D) of part or all of said heavy cut resulting from the fractionation step (c), with at least one hydrocarbon solvent, to obtain a deasphalted oil DAO and residual asphalt;

optionally a second fractionation step in a second fractionation section (E) of a part or all of the DAO resulting from the deasphalting step (d) into at least one heavy fraction of DAO and a light fraction of DAO;

a recycling step (f) of at least a portion of the DAO resulting from step (d) and / or at least a portion of the heavy fraction of the DAO resulting from step (e) at an additional hydroconversion step (a ₂ ) and / or an intermediate separation step (b ₎ ).

16. Process according to any one of the preceding claims, comprising recycling (f) all of the DAO resulting from stage (d) or all of the heavy fraction resulting from the second stage of fractionation (e). at the last additional hydroconversion stage (a, ·), and preferably in the additional hydroconversion stage (a ₂ ) when n is 2 and in addition all of the liquid effluent from the step (ai) is sent to step (bi), all of the heavy fraction resulting from step (bi) is sent in step (a ₂ ), all of the hydroconverted liquid effluent from step (a ₂ ) is sent in step (c), and the entire heavy cut resulting from step (c) is sent to step (d).

17. Process according to any one of claims 1 to 15, comprising the recycling (f) of all the DAO resulting from stage (d) or all of the heavy fraction resulting from the second fractionation stage ( e) at an intermediate separation step (b _y ), and preferably at the intermediate separation step (bi) between the initial hydroconversion step (a 1) and the additional hydroconversion step (a ₂ ) when n is equal to 2 and in addition all of the liquid effluent from step (a1) is sent to step (b1), all of the heavy fraction from step (b1) is sent in step (a ₂ ), all of the hydroconverted liquid effluent from step (a ₂ ) is sent to step (c), and all of the heavy cut resulting from step (a) is c) is sent to step (d).

18. A method according to any one of claims 1 to 15, having no intermediate separation step (b _y -) and comprising the recycling (f) of all the DAO from step (d) to the last additional hydroconversion stage (a, ·), and preferably in the additional hydroconversion stage (a ₂ ) when n is 2 and in addition all of the liquid effluent from the step (a1) is sent to step (a ₂ ), all of the hydroconverted liquid effluent from step (a ₂ ) is sent in step (c), and the entire heavy cut out of step (c) is sent to step (d).

19. A method according to any one of claims 1 to 18, wherein said hydroconversion catalyst of said at least one triphasic reactor of the initial hydroconversion section (Ai) and the additional hydroconversion section (s) (A, ·) contains at least one non-noble group VIII metal selected from nickel and cobalt and at least one Group VI B metal selected from molybdenum and tungsten, and preferably having an amorphous support.