EP3728518B1 - Method for converting heavy hydrocarbon feedstocks with recycling of a deasphalted oil - Google Patents

Description

Field of the invention

The present invention relates to the refining and conversion of heavy hydrocarbon feeds derived 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 of at least 300°C, and containing inter alia asphaltenes, sulphurous and nitrogenous impurities and metals. It is sought to convert these feedstocks into lighter products that can be used as fuels, for example to produce gasoline or diesel, or raw materials for the petrochemical industry.

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

General context

The feedstocks that it is desired to process in the context of the present invention are either crude oils or heavy hydrocarbon fractions resulting from the distillation of a crude oil, also called petroleum residues, and contain a fraction of at least least 50% having a boiling temperature of at least 300°C, preferably at least 350°C and most preferably at least 375°C. They are preferably vacuum residues containing a fraction of at least 50% have a boiling temperature of at least 450°C, and preferably of 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 content of C ₇ asphaltenes 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 at least 100 ppm by weight.

The recovery of these heavy loads is relatively difficult, both technically and economically.

Indeed, the market is above all in demand for fuels that can be distilled at atmospheric pressure at a temperature below 380°C, or even 320°C. With regard to crude oils, their atmospheric distillation leads to variable contents 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 in the Athabasca region in the northern Canada. It is therefore necessary to convert these residues, by transforming the heavy molecules of residues to produce refined products made up of lighter molecules. These refined products generally have a much higher hydrogen to carbon ratio than the starting heavy cuts. A series of processes used to produce refined light cuts, such as hydrocracking, hydrotreating and hydroconversion processes, are therefore based on the addition of hydrogen into the molecules, preferably at the same time as the cracking of these heavy molecules.

The conversion of heavy feeds depends on a large number of parameters such as the composition of the feed, the technology of the reactor used, the severity of the operating conditions (temperature, pressure, partial pressure of hydrogen, residence time, etc.) , the type of catalyst used and its activity. By increasing the severity of the operation, the conversion of heavy feeds to light products is increased, but by-products, such as coke precursors and sediments, begin to be formed significantly via side reactions. The advanced conversion of heavy feedstocks therefore very often results in the formation of solid, very 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, to the fouling of the process equipment, and in particular the separation and distillation equipment. As a result, the refiner is obliged to reduce the conversion of heavy feeds in order to avoid stopping the hydroconversion unit.

The formation of these sediments in hydrotreating and hydroconversion processes therefore depends very strongly on the quality of the feed and the severity of the operation. More specifically, the asphaltenes present in the feed are mainly converted by dealkylation under severe hydroconversion conditions and thereby form molecules comprising highly condensed aromatic rings which precipitate in the form of sediments.

• un premier type de procédé, connu sous le nom de « voie indirecte », met en œuvre l'unité de désasphaltage placée en amont de l'unité d'hydroconversion. Selon cette voie, la charge est traitée au moins en partie dans une unité de désasphaltage avant d'être envoyée au moins en partie à une unité d'hydroconversion comportant un ou plusieurs réacteurs d'hydroconversion en présence d'hydrogène. Le brevet US 7 214 308 décrit ainsi un procédé de conversion de résidu atmosphérique ou sous vide issu de la distillation de pétroles bruts lourds, dans lequel le résidu est d'abord envoyé dans une unité de désasphaltage au solvant produisant un flux de DAO et un flux d'asphalte, les deux flux étant ensuite traités séparément dans des réacteurs fonctionnant en lit bouillonnant. Le procédé permet alors un niveau de conversion plus élevé du résidu car l'hydroconversion séparée du flux de DAO met en œuvre un catalyseur spécifique au traitement de la DAO et peut être est opérée de manière à atteindre une conversion plus poussée. Un inconvénient principal de la voie indirecte réside dans la taille importante requise pour le désasphalteur conduisant à des coûts d'investissements et d'opération importants.
• un deuxième type de procédé, connu sous le nom de « voie directe », met en œuvre une unité de désasphaltage placée en aval de l'unité d'hydroconversion. En général, dans ce type de procédé, une étape de distillation atmosphérique, et éventuellement une étape de distillation sous vide successive à l'étape de distillation atmosphérique, est mise en œuvre entre les deux étapes unitaires constituées par l'hydroconversion et le désasphaltage.

C'est le cas par exemple du procédé décrit dans le brevet FR 2 753 984 , dans lequel une charge lourde est d'abord envoyée dans une section d'hydroconversion comprenant au moins un réacteur triphasique contenant un catalyseur d'hydroconversion en lit bouillonnant et de l'hydrogène et fonctionnant à courant ascendant de liquide et de gaz. Les conditions appliquées dans la section réactionnelle d'hydroconversion permettent d'obtenir un effluent liquide à teneur réduite en carbone Conradson, en métaux, en azote et en soufre. Cet effluent est ensuite séparé en plusieurs fractions, dont une ou plusieurs fractions résiduelles : l'effluent liquide hydroconverti est envoyé dans une zone de distillation atmosphérique produisant un distillat et un résidu atmosphérique, et au moins une partie du résidu atmosphérique est envoyé dans une zone de distillation sous vide à la suite de laquelle on récupère un distillat sous vide et un résidu sous vide Le résidu sous vide est alors envoyé au moins en partie dans une section de désasphaltage dans laquelle est mis en œuvre un extracteur liquide-liquide à l'aide d'un solvant dans des conditions de désasphaltage connues de l'homme du métier permettant d'obtenir une DAO et un asphalte résiduel. La DAO ainsi obtenue fait ensuite l'objet d'un hydrotraitement, soit en lit fixe, en lit mobile, en lit bouillonnant et/ou en lit hybride, dans des conditions permettant de réduire en particulier sa teneur en métaux, en soufre, en azote et en carbone Conradson et d'obtenir, après une nouvelle séparation par distillation, une fraction gazeuse, un distillat atmosphérique que l'on peut scinder en une fraction essence et gazole envoyé ensuite au pool carburants et une fraction plus lourde hydrotraitée. Cette fraction plus lourde peut ensuite être alors envoyée dans une section de craquage catalytique ou hydrocraquage catalytique par exemple.Processes for the hydroconversion of heavy hydrocarbon feedstocks are well known to those skilled in the art. Specifically,
conventional heavy load conversion schemes comprise a solvent deasphalting step (SDA for Solvent DeAsphalting in English) and a hydroconversion step carried out in a fixed bed, in a moving bed, in an ebullating bed and/or in a hybrid bed. The hydroconversion stages being carried out in a fixed bed, in a moving bed, in an ebullating bed and/or in a hybrid bed depending on the feed to be treated, these stages therefore always contain at least one catalyst which is maintained in the reactor during the operation. 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 catalyst entrained (known as "slurry" according to the English terminology). Saxon) which enters the reactor with the load and which is carried out of the reactor with the effluents. Deasphalting and hydroconversion are conventionally carried out successively. In particular, there are two types of heavy load conversion processes combining deasphalting and hydroconversion:

• a first type of process, known as the “indirect route”, uses the deasphalting unit placed upstream of the hydroconversion unit. According to this route, the charge 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. The patent US 7,214,308 thus describes a process for converting atmospheric or vacuum residue from the distillation of heavy crude oils, in which the residue is first sent to a solvent deasphalting unit producing a DAO stream and an asphalt stream, the two streams are then treated separately in reactors operating in an ebullated bed. The process then allows a higher level of conversion of the residue because the separate hydroconversion of the DAO stream uses a catalyst specific to the treatment of the DAO and can be operated in such a way as to achieve a more thorough conversion. A main drawback of the indirect route lies in the large size required for the deasphalter leading to significant investment and operating costs.
• a second type of process, known as the “direct route”, uses 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 implemented between the two unit steps consisting of hydroconversion and deasphalting.

This is the case, for example, of the process described in the patent FR 2 753 984 , in which a heavy load is first sent to a hydroconversion section comprising at least one three-phase reactor containing an ebullated bed hydroconversion catalyst and hydrogen and operating in an upward flow of liquid and gas. The conditions applied in the hydroconversion reaction section make it possible to obtain a liquid effluent with a reduced content of Conradson carbon, metals, nitrogen and 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 part of the atmospheric residue is sent to a zone vacuum distillation following which a vacuum distillate and a vacuum residue are recovered. The vacuum residue is then sent at least in part to a deasphalting section in which a liquid-liquid extractor is implemented at the using a solvent under deasphalting conditions known to those skilled in the art, making it possible 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 an ebullating bed and/or in a hybrid bed, under conditions making it possible to reduce in particular its content of metals, sulphur, nitrogen and carbon Conradson and to obtain, after a new separation by distillation, a gaseous fraction, an atmospheric distillate which 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.

The documents US 2010/320122A , US 6,017,441 , US 3,905,892 , US 4,176,048 , US 2012/061293A and US 8,287,720 describe various possible configurations for the direct route, in which a first hydroconversion stage is carried out followed by the stage of deasphalting of the heavy cut resulting from an intermediate separation of the hydroconverted effluent, then a second stage of hydroconversion, hydrotreating or hydrocracking of DAO. In these configurations, the formation of coke and sediments can still occur during the second stage of hydroconversion in the case where the DAO is co-processed with a feed containing asphaltenes. In addition, a large amount of asphalt is produced during the deasphalting step after the first low asphaltene conversion hydroconversion step, as in the case of the scheme proposed in the patent US 4,176,048 . This asphalt is a low-value product that is more difficult to convert into fuels.

The international request WO2010/033487A2 describes a "slurry" process for converting a heavy charge of hydrocarbons comprising two stages of hydroconversion (hydrocracking), and an optional deasphalting treatment (SDA) that can be implemented in an intermediate unit positioned after one of the intermediate separation.

Another configuration according to the direct route consists in carrying out the stage of deasphalting of the heavy cuts after a stage of hydroconversion thus making it possible to minimize the quantity of asphalt produced, then to recycle the DAO at the entrance to 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 separation zones, increasing the investment required and the operating cost compared to a conversion process without DAO recycling. Furthermore, in this configuration, coke and sediment formation problems may still occur during the hydroconversion step where the DAO is recycled and co-processed with the heavy feed containing asphaltenes.

Objects and summary of the invention

The present invention aims to solve, at least partially, the problems mentioned above in relation to the methods for converting heavy loads of the prior art integrating hydroconversion and deasphalting stages.

In particular, one of the objectives of the invention is to provide a process for the conversion of heavy loads of hydrocarbons integrating hydroconversion and deasphalting stages in which the stability of the effluents is improved for a given level of conversion of the heavy loads, thus making it possible to push the conversion further 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 process in which the formation of coke and sediments is limited during the hydroconversion, thus reducing the problems of deactivation of the catalysts used in the reaction zones and of fouling of the equipment used. implemented in the process.

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

• une étape initiale d'hydroconversion (a₁) d'au moins une partie de ladite charge lourde d'hydrocarbures en présence d'hydrogène dans une section d'hydroconversion initiale, réalisée dans des conditions permettant d'obtenir un effluent liquide à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote ;
• (n-1) étape(s) d'hydroconversion supplémentaire(s) (a _i ) dans (n-1) section(s) d'hydroconversion supplémentaire(s), en présence d'hydrogène, d'au moins une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion précédente (a _i-1) ou éventuellement d'une fraction lourde issue d'une étape optionnelle de séparation intermédiaire (b _j ) dans une section de séparation intermédiaire entre deux étapes d'hydroconversion consécutives séparant une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion précédente (a _i-1) pour produire au moins une fraction lourde bouillant majoritairement à une température supérieure ou égale à 350°C, les (n-1) étape(s) d'hydroconversion supplémentaire(s) (a _i ) étant réalisées de manière à obtenir un effluent liquide hydroconverti à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote,

n étant le nombre total d'étapes d'hydroconversion, avec n supérieur ou égal à 2, i étant un entier allant de 2 à n et j étant un entier allant de 1 à (n-1), et les sections d'hydroconversion initiale et supplémentaire(s) comportant chacune au moins un réacteur triphasique fonctionnant en lit bouillonnant ou en lit hybride contenant au moins un catalyseur d'hydroconversion étant utilisé sous forme d'extrudés ou de billes;

• une première étape de fractionnement (c) dans une première section de fractionnement d'une partie ou de la totalité de l'effluent liquide hydroconverti issu de la dernière étape d'hydroconversion supplémentaire (a_n ) produisant au moins une coupe lourde bouillant majoritairement à une température supérieure ou égale à 350°C, ladite coupe lourde contenant une fraction résiduelle bouillant à une température supérieure ou égale à 540°C ;
• une étape de désasphaltage (d) dans un désasphalteur d'une partie ou de la totalité de ladite coupe lourde issue de l'étape de fractionnement (c), avec au moins un solvant hydrocarboné, pour obtenir une huile désasphaltée DAO et un asphalte résiduel ;
• éventuellement une deuxième étape de fractionnement (e) dans une deuxième section de fractionnement d'une partie ou de la totalité de la DAO issue de l'étape de désasphaltage (d) en au moins une fraction lourde de DAO et une fraction légère de DAO ;
• une étape de recyclage (f) d'au moins une partie de la DAO issue de l'étape (d) et/ou d'au moins une partie de la fraction lourde de la DAO issue de l'étape (e) à une étape d'hydroconversion supplémentaire (a _i ) et/ou à une étape de séparation intermédiaire (b _j ).

Thus, to achieve at least one of the aforementioned objectives, among others, the present invention proposes a process for converting a heavy charge of hydrocarbons containing a fraction of at least 50% having a boiling point at least 300°C, and containing sulphur, Conradson carbon, metals, and nitrogen, comprising the following successive steps:

• an initial stage of hydroconversion (a ₁ ) of at least part of said heavy charge of hydrocarbons in the presence of hydrogen in an initial hydroconversion section, carried out under conditions making it possible to obtain a liquid effluent with a reduced content sulfur, Conradson carbon, metals, and nitrogen;
• (n-1) additional hydroconversion step(s) ( a _i ) in (n-1) additional hydroconversion section(s), in the presence of hydrogen, of at least a part or all of the liquid effluent from the preceding hydroconversion step ( a _{i -1} ) or possibly from a heavy fraction from an optional intermediate separation step ( b _j ) in an intermediate separation section between two consecutive hydroconversion stages separating part or all of the liquid effluent from the preceding hydroconversion stage ( a _{i -1} ) to produce at least one heavy fraction boiling mainly at a temperature greater than or equal to 350° C, the (n-1) additional hydroconversion step(s) ( a _i ) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur, Conradson carbon, metals and nitrogen content,

n being the total number of hydroconversion steps, with n greater than or equal to 2, i being an integer ranging from 2 to n and j being an integer ranging from 1 to (n-1), and the hydroconversion sections initial and additional(s) each comprising at least one three-phase reactor operating in an ebullated bed or in a hybrid bed containing at least one hydroconversion catalyst being used in the form of extrudates or beads;

• a first fractionation step (c) in a first fractionation section of part or all of the hydroconverted liquid effluent from the last additional hydroconversion step ( a _n ) producing at least one heavy cut boiling mainly at a temperature greater than or equal to 350°C, said heavy cut containing a residual fraction boiling at a temperature greater than or equal to 540°C;
• a deasphalting step (d) in a deasphalter of part or all of said heavy cut from the fractionation step (c), with at least one hydrocarbon solvent, to obtain a deasphalted oil DAO and a residual asphalt ;
• optionally a second stage of fractionation (e) in a second fractionation section of part or all of the DAO from the deasphalting stage (d) into at least one heavy DAO fraction and one light DAO fraction ;
• a step of recycling (f) at least part of the DAO from step (d) and/or at least part of the heavy fraction of the DAO from step (e) at a additional hydroconversion step ( a _i ) and/or an intermediate separation step ( b _j ).

The heavy hydrocarbon charge preferably has a sulfur content of at least 0.1% by weight, a Conradson carbon content of at least 0.5% by weight, a C ₇ asphaltenes content of at least 1% weight, and a metal content of at least 20 ppmw.

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

According to the invention, said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating in an ebullated bed, with an ascending current of liquid and gas, or 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 of said three-phase reactor.

According to one implementation of the invention, the initial hydroconversion step ( a ₁ ) 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 speed hourly space VVH relative to the volume of each three-phase reactor comprised between 0.05 h ^-1 and 10 h ^-1 and under a quantity of hydrogen mixed with the heavy hydrocarbon charge comprised between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of heavy oil load.

According to one implementation of the invention, the additional hydroconversion step(s) ( a _n ) are operated at a temperature between 300° C. and 550° C., and higher than the temperature operated in the hydroconversion step initial ( a ₁ ), under a quantity of hydrogen mixed with the heavy hydrocarbon charge 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 in the initial hydroconversion step ( a ₁ ), under an absolute pressure of between 2 and 38 MPa, and at an hourly space velocity VVH relative to the volume of each three-phase reactor of between 0.05 h ^-1 and ^10:00 a.m.

According to one implementation of the invention, the intermediate separation section comprises one or more flash drums 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 drum.

According to one implementation of the invention, the first fractionation section comprises one or more flash drums 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 set of several flash drums in series and atmospheric and vacuum distillation columns.

According to one implementation 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 carbon atoms. of carbon, and a solvent/filler (volume/volume) ratio of between 3/1 and 16/1, and preferably between 4/1 and 8/1.

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

According to one implementation 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.

• le recyclage (r ₁) d'une partie ou de la totalité de la fraction légère de la DAO issue de l'étape (e) dans la section d'hydroconversion initiale et/ou dans au moins une section d'hydroconversion supplémentaire et/ou dans au moins une section de séparation intermédiaire et/ou dans la première section de fractionnement ;
• le recyclage (r ₂) d'une partie de la fraction lourde de la DAO issue de l'étape (f) dans la première section de fractionnement ;
• le recyclage (r ₃) d'une partie de la DAO issue de l'étape (d) dans la première section de fractionnement ;
• le recyclage (r₄ ) d'une partie ou de la totalité de l'asphalte résiduel issu de l'étape (d) dans la section d'hydroconversion initiale et/ou dans au moins une section d'hydroconversion supplémentaire ;
• le recyclage (r ₅) d'une partie de l'effluent liquide hydroconverti d'une section d'hydroconversion supplémentaire donnée :
  • dans la section d'hydroconversion initiale, et/ou
  • dans une autre section d'hydroconversion supplémentaire positionnée en amont de ladite section donnée, et/ou
  • dans une section de séparation intermédiaire positionnée en amont de ladite section donnée ;
• le recyclage (r ₆) d'une partie de la fraction lourde et/ou d'une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue d'une section intermédiaire donnée :
  • dans la section d'hydroconversion initiale, et/ou
  • dans une section d'hydroconversion supplémentaire positionnée en amont de ladite section intermédiaire donnée, et/ou
  • dans une autre section de séparation intermédiaire positionnée en amont de ladite section donnée ;
• le recyclage (r ₇) d'une partie de la fraction lourde et/ou d'une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue de la première section de fractionnement :
  • dans la section d'hydroconversion initiale, et/ou
  • dans une section d'hydroconversion supplémentaire, et/ou
  • dans une section de séparation intermédiaire.

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

• the recycling ( r ₁ ) of part or all of the light fraction of the DAO 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;
• the recycling ( r ₂ ) of part of the heavy fraction of the DAO resulting from stage (f) in the first fractionation section;
• the recycling ( r ₃ ) of part of the DAO resulting from step (d) in the first fractionation section;
• the 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;
• the recycling ( r ₅ ) of part of the hydroconverted liquid effluent from 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 ) of part 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 ) of part of the heavy fraction and/or part or all of one or more intermediate fractions 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 implementation of the invention, n is equal to 2.

According to one implementation of the invention, the process comprises recycling (f) all of the DAO from step (d) or all of the heavy fraction from the second fractionation step (e) in the last additional hydroconversion step ( a _i ), and preferably in the additional hydroconversion step ( a ₂ ) when n is equal to 2 and when, in addition, all of the liquid effluent from the step ( a ₁ ) is sent to step ( b ₁ ), all of the heavy fraction from step ( b ₁ ) is sent to step ( a ₂ ), all of the hydroconverted liquid effluent from step ( a ₂ ) is sent to step (c), and all of the heavy cut from step (c) is sent to step (d).

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

According to one implementation of the invention, the method does not include an intermediate separation step ( b _j ) and includes the recycling (f) of all of the DAO from step (d) to the last step additional hydroconversion steps ( a _i ), and preferably in the additional hydroconversion step ( a ₂ ) when n is equal to 2 and when, in addition, all of the liquid effluent from step ( a ₁ ) is sent to stage ( a ₂ ), all of the hydroconverted liquid effluent from stage ( a ₂ ) is sent to stage (c), and all of the heavy cut from the step (c) is sent to step (d).

According to one implementation of the invention, the hydroconversion catalyst of said at least one three-phase reactor of the initial hydroconversion section and of the additional hydroconversion section(s) contains at least one metal from group VIII not -noble chosen from nickel and cobalt and at least one group VIB metal chosen 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 specific examples of implementation of the invention, given by way of non-limiting examples, the description being partly made with reference to the appended figures described below.

Brief description of figures

• The figure 1 is a block diagram of the implementation of the conversion method according to the invention.
• The picture 2 is a diagram of the process according to a first embodiment in which at least part of a heavy fraction of the DAO is recycled in a second hydroconversion section.
• The picture 3 is a diagram of the process according to a third embodiment in which at least a part of the DAO is recycled in the intermediate separation section to the two hydroconversion sections.
• The figure 4 is a diagram of the process according to a second embodiment in which at least a part of the DAO is recycled in a second hydroconversion section.
• The figure 5 is a diagram of the process according to a fourth embodiment in which at least part of the DAO is recycled in a second section hydroconversion following 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 includes hydroconversion of said feedstocks and deasphalting of at least part of the hydroconverted effluent in the form of a succession of specific steps.

In the remainder of the description, reference is made to the figure 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 stage, and at least one stage deasphalting of a heavy fraction of the effluent from the hydroconversion, with recycling of at least part of the DAO downstream of the first hydroconversion stage. The DAO is either recycled when it leaves 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 charge of hydrocarbons greater than 70%, and preferably greater than 80%, this level of conversion not always being able to be achieved using conventional methods which are limited by the stability of the liquid effluents.

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

• une étape initiale d'hydroconversion (a ₁) d'au moins une partie de ladite charge lourde d'hydrocarbures en présence d'hydrogène dans une section d'hydroconversion initiale A₁ , réalisée dans des conditions permettant d'obtenir un effluent liquide à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote ;
• (n-1) étape(s) d'hydroconversion supplémentaire(s) (a _i ) dans (n-1) section(s) d'hydroconversion supplémentaire(s) A _i , en présence d'hydrogène, d'au moins une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion précédente (a _i-1) ou éventuellement d'une fraction lourde issue d'une étape optionnelle de séparation intermédiaire (b _j ) entre deux étapes d'hydroconversion consécutives séparant une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion précédente (a _i-1) pour produire au moins une fraction lourde bouillant majoritairement à une température supérieure ou égale à 350°C, les (n-1) étape(s) d'hydroconversion supplémentaire(s) (a _i ) étant réalisées de manière à obtenir un effluent liquide hydroconverti à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote ;

n étant le nombre total d'étapes d'hydroconversion, avec n supérieur ou égal à 2, i étant un entier allant de 2 à n et j étant un entier allant de 1 à (n-1), et les sections d'hydroconversion initiale A ₁ et supplémentaire(s) A _i comportant chacune au moins un réacteur triphasique contenant au moins un catalyseur d'hydroconversion ;

• une première étape de fractionnement (c) dans une première section de fractionnement C d'une partie ou de la totalité de l'effluent liquide hydroconverti issu de la dernière l'étape d'hydroconversion supplémentaire (a_n ) pour produire au moins une coupe lourde bouillant majoritairement à une température supérieure ou égale à 350°C, ladite coupe lourde contenant une fraction résiduelle bouillant à une température supérieure ou égale à 540°C ;
• une étape de désasphaltage (d) dans un désasphalteur D d'une partie ou de la totalité de ladite coupe lourde issue de l'étape de fractionnement (c), avec au moins un solvant hydrocarboné, pour obtenir une huile désasphaltée DAO et un asphalte résiduel ;
• éventuellement une deuxième étape de fractionnement (e) dans une deuxième section de fractionnement E d'une partie ou de la totalité de la DAO issue de l'étape de désasphaltage (d) en au moins une fraction lourde de DAO et une fraction légère de DAO ;
• une étape de recyclage (f) d'au moins une partie de la DAO issue de l'étape (d) et/ou d'au moins une partie de la fraction lourde de la DAO issue de l'étape (e) à une étape d'hydroconversion supplémentaire (a _i ) et/ou à une étape de séparation intermédiaire (b _j ).

Thus, there is proposed a process for converting a heavy hydrocarbon charge, for example a crude oil or the heavy hydrocarbon fraction resulting from the atmospheric or vacuum distillation of a crude oil, said charge containing a fraction of 'to least 50% having a boiling point of at least 300°C, comprising the following successive steps:

• an initial stage of hydroconversion ( a ₁ ) of at least part of said heavy hydrocarbon charge in the presence of hydrogen in an initial hydroconversion section A ₁ , carried out under conditions making it possible to obtain a liquid effluent at reduced sulfur, Conradson carbon, metals, and nitrogen;
• (n-1) additional hydroconversion step(s) ( a _i ) in (n-1) additional hydroconversion section(s) A _i , in the presence of hydrogen, of at least part or all of the liquid effluent from the previous hydroconversion step ( a _{i -1} ) or possibly from a heavy fraction from an optional intermediate separation step ( b _j ) between two consecutive hydroconversion separating part or all of the liquid effluent from the previous hydroconversion step ( a _{i -1} ) to produce at least one heavy fraction boiling mainly at a temperature greater than or equal to 350°C, the ( n-1) additional hydroconversion step(s) ( a _i ) being carried out so as to obtain a hydroconverted liquid effluent with a reduced sulfur, Conradson carbon, metals and nitrogen content;

n being the total number of hydroconversion steps, with n greater than or equal to 2, i being an integer ranging from 2 to n and j being an integer ranging from 1 to (n-1), and the hydroconversion sections initial A ₁ and additional(s) A _i each comprising at least one three-phase 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 from the last additional hydroconversion step ( a _n ) to produce at least one cut heavy boiling mainly at a temperature greater than or equal to 350° C., said heavy cut containing a residual fraction boiling at a temperature greater than or equal to 540° C.;
• a deasphalting step (d) in a deasphalter D of part or all of said heavy cut 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 (e) in a second fractionation section E of part or all of the DAO from the deasphalting step (d) into at least one heavy fraction of DAO and a light fraction of CAD;
• a step of recycling (f) at least part of the DAO from step (d) and/or at least part of the heavy fraction of the DAO from step (e) at a additional hydroconversion step ( a _i ) and/or an intermediate separation step ( b _j ).

• une étape initiale d'hydroconversion (a ₁) d'au moins une partie de ladite charge lourde d'hydrocarbures en présence d'hydrogène dans une section d'hydroconversion initiale A₁ , réalisée dans des conditions permettant d'obtenir un effluent liquide à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote ;
• une étape d'hydroconversion supplémentaire (a ₂) dans une section d'hydroconversion supplémentaire A ₂ , en présence d'hydrogène, d'au moins une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion initiale (a ₁ ) ou éventuellement d'une fraction lourde issue d'une étape optionnelle de séparation intermédiaire (b ₁ ) entre les étapes d'hydroconversion initiale (a ₁ ) et supplémentaire (a ₂ ) séparant une partie ou la totalité de l'effluent liquide issu de l'étape d'hydroconversion initiale (a ₁ ) pour produire au moins une fraction lourde bouillant majoritairement à une température supérieure ou égale à 350°C, l'étape d'hydroconversion supplémentaire (a ₂ ) étant réalisées de manière à obtenir un effluent liquide hydroconverti à teneur réduite en soufre, en carbone Conradson, en métaux, et en azote,

les sections d'hydroconversion initiale A ₁ et supplémentaire A ₂ comportant chacune au moins un réacteur triphasique contenant au moins un catalyseur d'hydroconversion;

• une première étape de fractionnement (c) dans une première section de fractionnement C d'une partie ou de la totalité de l'effluent liquide hydroconverti issu de l'étape d'hydroconversion supplémentaire (a ₂) pour produire au moins une coupe lourde bouillant majoritairement à une température supérieure ou égale à 350°C, ladite coupe lourde contenant une fraction résiduelle bouillant à une à une température supérieure ou égale à 540°C ;
• une étape de désasphaltage (d) dans un désasphalteur D d'une partie ou de la totalité de ladite coupe lourde issue de l'étape de fractionnement (c), avec au moins un solvant hydrocarboné, pour obtenir une huile désasphaltée DAO et un asphalte résiduel ;
• éventuellement une deuxième étape de fractionnement (e) dans une deuxième section de fractionnement E d'une partie ou de la totalité de la DAO issue de l'étape de désasphaltage (d) en au moins une fraction lourde de DAO et une fraction légère de DAO ;
• une étape de recyclage (f) d'au moins une partie de la DAO issue de l'étape (d) et/ou d'au moins une partie de la fraction lourde de la DAO issue de l'étape (e) à une l'étape d'hydroconversion supplémentaire (a ₂ ) et/ou à une étape de séparation intermédiaire (b ₁ ).

According to a preferred implementation, the method according to the invention contains two hydroconversion steps, and an optional intermediate separation step between these two hydroconversion steps. According to this implementation, n is equal to 2, and the method then comprises:

• an initial stage of hydroconversion ( a ₁ ) of at least part of said heavy hydrocarbon charge in the presence of hydrogen in an initial hydroconversion section A ₁ , carried out under conditions making it possible to obtain a liquid effluent at reduced sulfur, Conradson carbon, metals, and nitrogen;
• an additional hydroconversion step ( a ₂ ) in an additional hydroconversion section A ₂ , in the presence of hydrogen, of at least part or all of the liquid effluent from the initial hydroconversion step ( a ₁ ) or possibly from a heavy fraction resulting from an optional intermediate separation step ( b ₁ ) between the initial ( a ₁ ) and additional ( a ₂ ) hydroconversion steps separating part or all of the effluent liquid resulting from the initial hydroconversion stage ( a ₁ ) to produce at least one heavy fraction boiling mainly at a temperature greater than or equal to 350° C., the additional hydroconversion stage ( a ₂ ) being carried out in such a way as to obtain a hydroconverted liquid effluent with a reduced sulfur, Conradson carbon, metals and nitrogen content,

the initial A ₁ and additional A ₂ hydroconversion sections each comprising at least one three-phase reactor containing at least one hydroconversion catalyst;

• a first fractionation stage (c) in a first fractionation section C of part or all of the hydroconverted liquid effluent from the additional hydroconversion stage ( a ₂ ) to produce at least one boiling heavy cut predominantly at a temperature greater than or equal to 350° C., said heavy cut containing a residual fraction boiling at a temperature greater than or equal to 540° C.;
• a deasphalting step (d) in a deasphalter D of part or all of said heavy cut 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 (e) in a second fractionation section E of part or all of the DAO from the deasphalting step (d) into at least one heavy fraction of DAO and a light fraction of CAD;
• a step of recycling (f) at least part of the DAO from step (d) and/or at least part of the heavy fraction of the DAO from step (e) at a the additional hydroconversion stage ( a ₂ ) and/or an intermediate separation stage ( b ₁ ).

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

The mixing of at least a part of the DAO and the effluent from the first hydroconversion section(s) in the process according to the invention makes it possible to supply the subsequent hydroconversion stage(s) with a feed having a reduced content of C ₇ asphaltenes and a higher content of aromatic compounds both compared to a process comprising a hydroconversion unit without recycling of the DAO, and compared to a process comprising a hydroconversion unit with recycling of the DAO upstream of a first stage of hydroconversion or hydrotreatment. 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 to reach higher levels in terms of feed conversion, while limiting sediment production.

The effluent from the last additional hydroconversion step is separated into several cuts. Deasphalting is then carried out on the heavy cut(s) produced in this separation step. The use of these cuts obtained at the highest level of conversion thus makes it possible to minimize the size required for the deasphalter and to minimize the quantity of asphalt produced. According to the invention, the DAO extracted by deasphalting is always recycled after the initial hydroconversion step, 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 entrance to the section of the last additional hydroconversion step. According to these two implementations, the size of the reactors of the first hydroconversion sections is 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 hydroconversion stages are impacted. The 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 in the stability of liquid effluents from areas where the highest conversion levels are reached. An operation to achieve higher conversion rates can therefore thus be envisaged in the process according to the invention.

Charge

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

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

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

The heavy hydrocarbon feed may also consist of atmospheric and/or vacuum residues from the atmospheric and/or vacuum distillation of effluents from thermal conversion, hydrotreating, hydrocracking and/or hydro conversion.

Preferably, the charge consists of vacuum residues. 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 even at least 540° C. °C. Vacuum resids can come directly from crude oil, or from other refining units, such as, but not limited to, residing hydrotreating, residing hydrocracking, and residing visbreaking. Preferably, the vacuum residues are vacuum residues from the vacuum distillation column of the primary fractionation of crude oil (known as “straight run” according to English terminology).

The feed may still consist of vacuum distillates, either directly from crude oil or from cuts from other refining units, such as, inter alia, cracking units, such as fluid bed catalytic cracking FCC (for “Fluid Catalytic Cracking” in English) and hydrocracking, and thermal conversion units, such as coking units or visbreaking units.

It may also consist of aromatic cuts extracted from a lubricant production unit, deasphalted oils from a deasphalting unit (raffinates from the deasphalting unit), asphalts from a deasphalting unit ( residues from the deasphalting unit).

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

All of these feedstocks can be used to form the heavy hydrocarbon feedstock treated according to the invention, alone or as a mixture.

The heavy charge of hydrocarbons treated according to the invention contains impurities, such as metals, sulfur, nitrogen, Conradson carbon. It may also contain heptane insolubles, 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%, or even greater than or equal to 1%, and may be greater than or equal to 2% by weight. The rate of asphaltenes C ₇ (compounds insoluble in heptane according to standard NFT60-115 or standard ASTM D 6560) 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 called coke, and by their tendency to produce sediments which severely limit the operability of the 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 the ASTM D 482 standard and represents, for those skilled in the art, a well-known evaluation of the quantity of carbon residues produced after pyrolysis under standard temperature and pressure conditions.

Initial hydroconversion step ( a ₁ )

In accordance with the invention, the heavy hydrocarbon charge is treated in the presence of hydrogen in a first hydroconversion stage ( a ₁ ), within an initial hydroconversion section A ₁ . The initial hydroconversion section comprises one or more three-phase reactors containing at least one hydroconversion catalyst, the reactors possibly being arranged in series and/or in parallel. These reactors can be bubbling bed and/or hybrid bed type reactors, depending on the feed to be treated.

The invention is particularly suitable for three-phase reactors operating in an ebullated bed, with an ascending current of liquid and gas. Thus, this initial hydroconversion step ( a ₁ ) is advantageously implemented in an initial hydroconversion section A ₁ comprising one or more three-phase hydroconversion reactors, which can be in series and/or in parallel, operating as a bed bubbling, typically using the technology and under the conditions of the H-Oil ^™ process as described for example in the patents US 4,521,295 Where US 4,495,060 Where US 4,457,831 Where US 4,354,852 , or in the article AlChE, March 19-23, 1995, Houston, Texas, paper number 46d, "Second generation ebullated bed technology ", or in the chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" of the book "Catalysis by Transition Metal Sulphides", published by Éditions Technip in 2013 . According to this implementation, each three-phase reactor is operated in a fluidized bed called an ebullating bed. Each reactor advantageously comprises a recirculation pump making it possible to maintain the catalyst in an ebullated bed by continuous recycling of at least part of a liquid fraction advantageously drawn off at the top of the reactor and reinjected at the bottom of the reactor.

The first hydroconversion stage ( a ₁ ) is carried out under conditions making it possible to obtain a liquid effluent with a reduced sulfur, Conradson carbon, metals and nitrogen content.

In this step ( a ₁ ), the feedstock is preferably transformed under specific hydroconversion conditions. Step ( a ₁ ) 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 between 300°C and 550°C, more preferably between 350°C and 500°C and more preferably between 370°C and 450°C. The hourly space velocity (HSV) relative to the volume of each three-phase reactor is preferably between 0.05 h ^-1 and 10 h ^-1 .

According to a preferred implementation, the VVH 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 VVH is between 0.05 h ^-1 and 0.09 h ^-1 . The amount of hydrogen mixed with the charge is preferably between 50 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of liquid charge, preferably between 100 and 2000 Nm ³ /m ³ and so very preferred between 200 and 1000 Nm ³ /m ³ .

The initial hydroconversion step ( a ₁ ) being carried out in an ebullated bed and/or in a hybrid bed depending on the feed to be treated, this step therefore contains at least one hydroconversion catalyst which is maintained in the reactor.

The hydroconversion catalyst used in the initial hydroconversion step ( a ₁ ) of the process according to the invention may contain one or more elements from groups 4 to 12 of the periodic table of elements, which may or may not be deposited on a support. . One can advantageously 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 metal from group VIII chosen from nickel and cobalt, and preferably nickel, said element from group VIII preferably being used in combination with at least one metal from group VIB chosen from molybdenum and tungsten, and preferably the Group VIB metal is molybdenum.

In this description, the groups of chemical elements are given according to the CAS classification ( CRC Handbook of Chemistry and Physics, publisher CRC press, editor DR 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 IUPAC classification.

Advantageously, the hydroconversion catalyst used in the initial hydroconversion step ( a ₁ ) comprises an alumina support and at least one group VIII metal chosen from nickel and cobalt, preferably nickel, and at least one metal of group VIB chosen from molybdenum and tungsten, preferably molybdenum. Preferably, the hydroconversion catalyst comprises nickel as a group VIII element and molybdenum as a group VIB element.

The content of non-noble group VIII metal, in particular nickel, is advantageously between 0.5% and 10%, expressed by weight of metal oxide (in particular NiO), and preferably between 1% and 6 % by 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 percentage of metal oxide relative to the weight of the catalyst.

This catalyst is 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 between 0.5 and 4.0 mm and a length between 1 and 5 mm. Extrudes 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 by 6 times the ratio between the volume of the particle and the external surface of the particle. The catalyst used in the form of extrudates, of beads 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 step ( a ₁ ) is carried out in a hybrid bed, simultaneously comprising at least one catalyst which is maintained in the reactor and at least one entrained catalyst which enters the reactor with the load and which is drawn outside the reactor with the effluents. In this case, a type of entrained catalyst, also called "slurry" according to English terminology, is therefore used in addition to the hydroconversion catalyst which is maintained in the reactor in an ebullated bed. The entrained catalyst has, as a difference, a particle size and a density adapted to its entrainment. By entrainment of the dispersed catalyst is meant its circulation in the three-phase reactor(s) by the liquid flows, said catalyst circulating with the charge in the said three-phase reactor(s), and being withdrawn from the said three-phase reactor(s) with the liquid effluent produced. These catalysts are well known to those skilled in the art.

The entrained catalyst can advantageously be obtained by injecting at least one active phase precursor directly into the hydroconversion reactor(s) and/or into the charge prior to the introduction of said charge into the hydroconversion stage(s). The addition of precursor can be introduced continuously or discontinuously (depending on the operation, the type of feedstock treated, the desired product specifications and the operability). According to one or more embodiments, the precursor(s) of entrained catalyst is (are) pre-mixed 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 pre-mixture of dilute precursor. According to one or more embodiments, the precursor or the dilute precursor pre-mixture is dispersed in the heavy hydrocarbon feedstock, for example by dynamic mixing (for example using a rotor, an agitator, etc. ), by static mixing (e.g. using an injector, by gavage, via a static mixer, etc.), or only added to the charge to obtain a mixture. All the mixing and agitation techniques known to those skilled in the art can be used to disperse the precursor or the mixture of precursors diluted in the charge of one or more hydroconversion stages.

The said 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, such as, 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, then be injected with the charge. Said entrained catalyst can also be formed and activated in situ under the reaction conditions of one of the hydroconversion steps.

• par broyage du catalyseur supporté d'hydroconversion, frais ou usé ou par broyage d'un mélange des catalyseurs frais et usé, ou
• par imprégnation d'au moins un précurseur de phase active sur un support présentant une granulométrie adaptée à son entraînement et de préférence une taille comprise entre 0,001 et 100 µm. La phase active peut être celle décrite plus haut pour le catalyseur d'hydroconversion utilisé dans l'étape d'hydroconversion initiale (a ₁), de même que le support. Leur description n'est pas répétée ici.

According to one embodiment, said entrained catalyst may 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
• by impregnation of at least one active phase precursor on a support having a particle size suitable for its entrainment and preferably a size comprised between 0.001 and 100 μm. The active phase may be that described above for the hydroconversion catalyst used in the initial hydroconversion step ( a ₁ ), 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 ( a ₁ ), the catalyst offered to each reactor being adapted to the feed sent into this 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 suitable for operation in an ebullated bed, and optionally one or more additional entrained catalyst(s).

As is known, and for example described in the patent FR 3 033 797 , the hydroconversion catalyst, when used, can be partly replaced by fresh catalyst, and/or used catalyst but with higher catalytic activity than the used catalyst to be replaced, and/or regenerated catalyst, and/ or rejuvenated catalyst (catalyst from a rejuvenation zone in which most of the metals deposited are removed, before sending the spent and rejuvenated catalyst to a regeneration zone in which the carbon and sulfur that it contains is removed contains thus increasing the activity of the catalyst), by withdrawing the used catalyst preferably at the bottom of the reactor, and by introducing the replacement catalyst either at the top or at the bottom of the reactor. This replacement of used catalyst is preferably carried out at regular time intervals, and preferably in bursts or almost continuously. The replacement of used catalyst can be done entirely or in part by used and/or regenerated and/or rejuvenated catalyst from the same reactor and/or from another reactor of any hydroconversion stage. The catalyst can be added with the metals as metal oxides, with the metals as metal sulfides, or after preconditioning. For each reactor, the rate of replacement of spent hydroconversion catalyst with fresh catalyst is advantageously between 0.01 kg and 10 kg per cubic meter of feedstock treated, and preferably between 0.1 kg and 3 kg per cubic meter load processed. This withdrawal and this replacement are carried out using devices that advantageously allow the continuous operation of this hydroconversion step.

As regards the replacement at least in part by regenerated catalyst, it is possible to send the spent catalyst withdrawn from the reactor to a regeneration zone in which the carbon and the sulfur which it contains are eliminated and then to return this catalyst regenerated in the hydroconversion step. As regards the replacement at least in part by rejuvenated catalyst, it is possible to send the spent catalyst withdrawn from the reactor to a rejuvenation zone in which the major part of the deposited metals is eliminated, before sending the spent catalyst and rejuvenated in an area of regeneration in which the carbon and the sulfur which it contains are eliminated and then this regenerated catalyst is returned to the hydroconversion stage.

• une ou plusieurs charges d'hydrocarbures externes (dans le sens externes au procédé selon l'invention et différentes de la charge initiale), de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, ou des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i), ces étapes (a _i) et (b _j ) étant décrites plus bas ;
• une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i) ;
• une partie de l'effluent d'une ou plusieurs étapes d'hydroconversion supplémentaires (a _i) ;
• une partie de la coupe lourde et/ou d'une ou de plusieurs des coupes intermédiaires et/ou d'une ou de plusieurs des coupes légères issues de la première étape de fractionnement (c) du procédé selon l'invention ;
• une partie ou la totalité de l'asphalte résiduel produit dans le désasphalteur D à l'étape de désasphaltage (d) ;
• une partie ou la totalité de la fraction légère de la DAO produite dans la deuxième étape de fractionnement (e) du procédé selon l'invention.

The initial hydroconversion section A ₁ can also receive, in addition to the heavy hydrocarbon charge, at least one of the following effluents:

• one or more external hydrocarbon feedstocks (in the sense external to the process according to the invention and different from the initial feedstock), preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, or vacuum residues;
• part of the heavy fraction from one or more intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i ), these stages ( a _i ) and ( b _j ) being described below;
• part or all of one or more intermediate fractions resulting from one or more intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i );
• part of the effluent from one or more additional hydroconversion stages ( a _i );
• 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) of the process according to the invention;
• some or all of the residual asphalt produced in the deasphalter D in the deasphalting step (d);
• 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 ₁ ) - optional

The liquid effluent from the initial hydroconversion stage ( a ₁ ) can then undergo an intermediate separation stage ( b ₁ ) in an intermediate separation section B ₁ , carried out between the initial hydroconversion stage ( a ₁ ) and an additional hydroconversion step following the initial hydroconversion step. This additional hydroconversion step is described below. According to the invention, this intermediate separation step ( b ₁ ) is preferred, but it remains optional. Indeed, the liquid effluent from the initial hydroconversion step ( a ₁ ) can alternatively be sent directly to the additional hydroconversion step.

Preferably, at least part of the liquid effluent resulting from the initial hydroconversion stage ( a ₁ ) is sent to the intermediate separation stage ( b ₁ ).

The intermediate separation stage ( b ₁ ) separates part or all of the liquid effluent from the initial hydroconversion stage ( a ₁ ) to produce at least one so-called heavy liquid fraction boiling mainly at a higher temperature or equal to 350°C.

This first intermediate separation step therefore produces at least two fractions including the heavy liquid fraction as described above, the other cut(s) being light and intermediate cut(s).

The light fraction thus separated contains dissolved light gases (H ₂ and C ₁ -C ₄ ), naphtha (fraction boiling at a temperature below 150°C), kerosene (fraction boiling between 150°C and 250°C) , and at least part 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 flash balloon. The gaseous hydrogen thus recovered can advantageously be recycled at the inlet of the initial hydroconversion stage ( a ₁ ).

The fractionation unit where the light fraction can be sent can also include a distillation column. In this case, the naphtha, kerosene and gas oil fractions of the light fraction sent to said column are separated.

The heavy liquid fraction from the intermediate separation stage ( b ₁ ), boiling mainly at a temperature greater than or equal to 350°C, contains at least one fraction boiling at a temperature greater than or equal to 540°C, called residue under void (which is the unconverted fraction). The heavy liquid fraction from the intermediate separation stage ( b ₁ ), boiling mainly at a temperature greater than or equal to 350° C., can also contain a fraction boiling between 375 and 540° C., called vacuum distillate. It may optionally also contain part of the gas oil 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 stage ( b ₁ ) can therefore separate the liquid effluent from the initial hydroconversion stage ( a ₁ ) into more than two liquid fractions, depending on the separation means implemented.

The intermediate separation section B ₁ comprises any separation means known to those skilled in the art.

The intermediate separation section B ₁ can thus comprise one or more following separation equipment: one or more flash drums arranged in series, one or more steam and/or hydrogen stripping columns, an atmospheric distillation column , a vacuum distillation column.

Preferably, this intermediate separation step ( b ₁ ) is carried out by one or more flash balloons arranged in series.

According to a preferred implementation, the intermediate separation step ( b ₁ ) is carried out by a single flash balloon. Preferably, the flash drum is at a pressure and a temperature close to the operating conditions of the last reactor of the initial hydroconversion step ( a ₁ ). This implementation is preferred in particular because it makes it possible to reduce the number of equipment and therefore the investment cost.

According to another implementation, the intermediate separation step ( b ₁ ) is carried out by a sequence of several flash drums, operating at operating conditions different from those of the last reactor of the initial hydroconversion step ( a ₁ ), and leading to the obtaining of at least the light liquid fraction, which can then be sent at least in part to a fractionation unit, and of at least the heavy liquid fraction, which is then sent at least in part to a second hydroconversion step ( a ₂ ).

In another implementation, the intermediate separation step ( b ₁ ) is carried out by one or more steam and/or hydrogen stripping columns. By this means, the effluent from the initial hydroconversion step ( a ₁ ) 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 in part to a second hydroconversion stage ( a ₂ ).

In another implementation; the intermediate separation stage ( b ₁ ) is carried out in an atmospheric distillation column separating the liquid effluent from the initial hydroconversion stage ( a ₁ ). The heavy liquid fraction recovered from the atmospheric distillation column is then sent at least in part to a second hydroconversion step ( a ₂ ).

In another implementation; the intermediate separation step ( b ₁ ) is carried out by an atmospheric distillation column separating the liquid effluent from the step initial hydroconversion ( a ₁ ), and by a vacuum distillation column receiving the residue from the atmospheric distillation column and producing the heavy liquid fraction which is then sent at least in part to a second hydroconversion stage ( a ₂ ).

The intermediate separation step ( b ₁ ) can also consist 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 can be subjected to a steam and/or hydrogen stripping stage using one or more stripping columns, in order to eliminate from the heavy fraction the compounds having a boiling point lower than 540°C.

• une partie de la charge lourde hydrocarbonée envoyée à l'étape d'hydroconversion (bypass);
• une ou plusieurs charges d'hydrocarbures externes, de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires B _j réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i), postérieures à l'étape (a ₁), comme détaillé plus loin ;
• une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) ;
• une partie de l'effluent liquide d'une ou plusieurs étapes d'hydroconversion supplémentaires (a _i ) décrites plus loin ;
• une partie de la coupe lourde et/ou d'une ou de plusieurs des coupes intermédiaires et/ou d'une ou de plusieurs des coupes légères issues de la première étape de fractionnement (c) détaillé plus bas ;
• une partie ou la totalité de la DAO produite dans le désasphalteur D à l'étape de désasphaltage (d) ;
• une partie ou la totalité de la fraction lourde de la DAO produite dans la deuxième étape de fractionnement (e) ;
• une partie ou la totalité de la fraction légère de la DAO produite dans la deuxième étape de fractionnement (e).

The intermediate separation section B ₁ can also receive, in addition to part or all of the liquid effluent from the initial hydroconversion step ( a ₁ ), at least one of the following effluents:

• part of the heavy hydrocarbon feed 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, vacuum residues;
• part of the heavy fraction from one or more intermediate separation stages B _j carried out between two consecutive additional hydroconversion stages ( a _i ), subsequent to stage ( a ₁ ), as detailed below;
• part or all of one or more intermediate fractions resulting from one or more intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i );
• part of the liquid effluent from one or more additional hydroconversion stages ( a _i ) 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 stage (c) detailed below;
• part or all of the DAO produced in the deasphalter D in the deasphalting step (d) ;
• part or all of the heavy fraction of the DAO produced in the second fractionation step (e) ;
• part or all of the light fraction of the DAO produced in the second fractionation step (e).

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

Additional hydroconversion step(s) ( a _i ) and optional intermediate separation step(s) ( b _j )

In accordance with the invention, part or all of the effluent from the initial hydroconversion step ( a ₁ ), or preferably part or all of the heavy fraction from the intermediate separation step ( b ₁ ), is treated in the presence of hydrogen in an additional hydroconversion step ( a ₂ ) carried out in an additional hydroconversion section A ₂ , which follows the initial hydroconversion step ( a ₁ ) or optionally l intermediate separation step ( b ₁ ).

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

Thus, the process according to the invention comprises (n-1) additional hydroconversion step(s) ( a _i ) in (n-1) additional hydroconversion section(s) A _j , in presence of hydrogen, of at least part or all of the liquid effluent from the preceding hydroconversion step ( a _{i -1} ) or possibly of a heavy fraction from the optional intermediate separation step ( b _j ) between two consecutive hydroconversion stages separating part or all of the liquid effluent from the preceding hydroconversion stage ( a _{i -1} ) to produce at least one heavy fraction boiling mainly at a higher temperature or equal to 350° C., the (n-1) additional hydroconversion stage(s) ( a _i ) being carried out so as to obtain a hydroconverted liquid effluent with a reduced content of sulphur, Conradson carbon, metals , and nitrogen.

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

i and j are indices. i is an integer ranging from 2 to n and j being an integer ranging from 1 to (n-1).

The additional hydroconversion section(s) A _i each comprise at least one three-phase reactor containing at least one hydroconversion catalyst, as described for the initial hydroconversion section A ₁ .

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

The (n-1) additional hydroconversion step(s) ( a _i ) are implemented in a manner similar to what was described for the initial hydroconversion step, and their description is therefore not 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 for the initial hydroconversion step ( a ₁ ), the (n-1) additional hydroconversion step(s) ( a _i ) are advantageously implemented in initial hydroconversion sections A ₁ comprising one or more three-phase hydroconversion reactors, which can be in series and/or in parallel, preferably operating in an ebullated bed, as described above for the initial hydroconversion step ( a ₁ ). According to this preferred implementation, each three-phase reactor is operated in a fluidized bed called an ebullating bed. Each reactor advantageously comprises a recirculation pump making it possible to maintain the catalyst in an ebullated bed by continuous recycling of at least part of a liquid fraction advantageously drawn off at the top of the reactor and reinjected at the bottom of the reactor.

In these additional hydroconversion steps, the operating conditions can be more severe than in the initial hydroconversion step, 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 reducing the quantity of hydrogen introduced into the reactor, remaining in the range between 50 and 5000 Nm ³ /m ³ of liquid filler, preferably between 100 and 2000 Nm ³ /m ³ , and even more preferably between 200 and 1000 Nm ³ /m ³ . The other pressure and VVH parameters are in ranges identical to those described for the initial hydroconversion step.

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 a DAO. In this case, the catalyst may have a porosity of the support or contain metal contents suitable for the hydroconversion of feedstocks containing DAO cuts.

With regard to the possible replacement of the spent 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 the hydroconversion of residual cuts containing a DAO. In this case, the catalyst replacement rate can be lower, suitable for the hydroconversion of feedstocks containing DAO cuts.

The other intermediate separation steps ( b _j ) each of which can be carried out between two consecutive additional hydroconversion steps A _i are also implemented in a manner similar to what has been described for the intermediate separation step ( b ₁ ), and the description of these steps ( b _j ) is therefore not repeated here.

In a preferred implementation, the process according to the invention always comprises an intermediate separation step ( b _j ) between two consecutive additional hydroconversion steps ( a _i ). According to an alternative implementation, the effluent from an additional hydroconversion stage ( a _i ) is sent directly to another additional hydroconversion stage ( a _{i + 1} ) following stage ( a _i ).

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

In accordance with the invention, at least part of the DAO from the deasphalting step (d) detailed below, and/or at least part of the heavy fraction of the DAO from a second fractionation step ( e) also detailed below, is recycled by being sent to an additional hydroconversion stage ( a _i ) and/or to an intermediate separation stage ( b _j ). The process according to the invention thus excludes recycling of the DAO or of a heavy fraction of the DAO in the initial hydroconversion step.

The DAO or the heavy fraction of the DAO thus recycled can then be co-treated in an additional hydroconversion section A _i with at least part of the effluent coming from the initial hydroconversion stage ( a ₁ ) or d a hydroconversion step additional ( a _i ), or more preferably co-treated with at least part of the heavy fraction from an intermediate separation step ( b _j ).

• une partie de la charge lourde hydrocarbonée envoyée à l'étape initiale d'hydroconversion (bypass) ;
• une ou plusieurs charges d'hydrocarbures externes, de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, ou des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires B _j ultérieures réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) ;
• une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) ultérieures réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) ;
• une partie de l'effluent d'une ou plusieurs étapes d'hydroconversion d'hydroconversion supplémentaires ultérieure (a _j+1) ;
• une partie de la coupe lourde et/ou d'une ou de plusieurs des coupes intermédiaires et/ou d'une ou de plusieurs des coupes légères issues de la première étape de fractionnement (c) du procédé selon l'invention ;
• une partie ou la totalité de la DAO produite dans le désasphalteur D à l'étape de désasphaltage (d) ;
• une partie ou la totalité de la fraction lourde de la DAO produite dans la deuxième étape de fractionnement (e) du procédé selon l'invention ;
• une partie ou la totalité de la fraction légère de la DAO produite dans la deuxième étape de fractionnement (e) ;
• une partie ou la totalité de l'asphalte résiduel produit dans le désasphalteur D à l'étape de désasphaltage (d).

Each additional hydroconversion section A _i can also receive, in addition to the effluent from the initial hydroconversion step or from a previous additional hydroconversion step ( a _{i -1} ) or even, preferably, in addition to the heavy fraction from an intermediate separation step ( b _j ), at least one of the following effluents:

• part of the heavy hydrocarbon feed sent to the initial hydroconversion stage (bypass);
• one or more external hydrocarbon feedstocks, preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, or vacuum residues;
• a part of the heavy fraction resulting from one or more subsequent intermediate separation stages B _j carried out between two consecutive additional hydroconversion stages ( a _i );
• part or all of one or more intermediate fractions resulting from one or more subsequent intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i );
• part of the effluent from one or more subsequent additional hydroconversion hydroconversion stages ( a _{j +1} );
• 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) of the process according to the invention;
• part or all of the DAO produced in the deasphalter D in the deasphalting step (d) ;
• 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) ;
• some or all of the residual asphalt produced in the deasphalter D in the deasphalting step (d).

• une partie de la charge lourde hydrocarbonée envoyée à l'étape d'hydroconversion (bypass);
• une ou plusieurs charges d'hydrocarbures externes, de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires B _j ultérieures réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) ;
• une partie ou de la totalité d'une ou plusieurs fractions intermédiaires issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) ultérieures réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) ;
• une partie de l'effluent liquide d'une ou plusieurs étapes d'hydroconversion supplémentaires (a _i ) ultérieures ;
• une partie de la coupe lourde et/ou d'une ou de plusieurs des coupes intermédiaires et/ou d'une ou de plusieurs des coupes légères issues de la première étape de fractionnement (c) ;
• une partie ou la totalité de la DAO produite dans le désasphalteur D à l'étape de désasphaltage (d) ;
• une partie ou la totalité de la fraction lourde de la DAO produite dans la deuxième étape de fractionnement (e) ;
• une partie ou la totalité de la fraction légère de la DAO produite dans la deuxième étape de fractionnement (e).

Each intermediate separation section B _j can also receive, in addition to part or all of the hydroconverted liquid effluent from the initial stage of hydroconversion ( a ₁ ) or of a preceding additional hydroconversion stage ( a _{i -1} ), at least one of the following effluents:

• part of the heavy hydrocarbon feed 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, vacuum residues;
• a part of the heavy fraction resulting from one or more subsequent intermediate separation stages B _j carried out between two consecutive additional hydroconversion stages ( a _i );
• part or all of one or more intermediate fractions resulting from one or more subsequent intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i );
• part of the liquid effluent from one or more subsequent additional hydroconversion stages ( a _i );
• 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) ;
• part or all of the DAO produced in the deasphalter D in the deasphalting step (d) ;
• part or all of the heavy fraction of the DAO produced in the second fractionation step (e) ;
• part or all of the light fraction of the DAO produced in the second fractionation step (e).

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

First fractionation step (c)

The hydroconverted liquid effluent from the last additional hydroconversion step ( a _n ) then undergoes at least part of a fractionation step (c) in a first fractionation section C.

This first fractionation stage (c) separates part or all of the effluent from stage ( a _n ) into several fractions including at least one heavy liquid fraction boiling mainly at a temperature above 350° C., preferably greater than 500°C and preferably greater than 540°C. The heavy liquid cut contains a fraction boiling at a temperature above 540° C., called vacuum residue (which is the unconverted fraction). It may contain part 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 including the heavy liquid fraction as described above, the other cut(s) being light and intermediate cut(s).

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

The first fractionating section C can thus comprise one or more following separation equipment: one or more flash drums arranged in series, and preferably a sequence of at least two successive flash drums, 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 linking at least two successive flash balloons.

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

According to another preferred implementation, 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 drums, 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 the investment costs and the operating costs.

• une partie de la charge lourde hydrocarbonée envoyée à l'étape d'hydroconversion (bypass);
• une ou plusieurs charges d'hydrocarbures externes, de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires B _j réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i) ;
• une partie de l'effluent liquide d'une ou plusieurs étapes d'hydroconversion supplémentaires (a _i) ;
• une partie d'une ou de plusieurs des coupes intermédiaires issues de la première étape de fractionnement (c) ;
• une partie de la DAO produite dans le désasphalteur D à l'étape de désasphaltage (d) ;
• une partie de la fraction lourde de la DAO produite dans la deuxième étape de fractionnement (e) ;
• une partie ou la totalité de la fraction légère de la DAO produite dans la deuxième étape de fractionnement (e).

The first fractionation section C can 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:

• part of the heavy hydrocarbon feed 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, vacuum residues;
• part of the heavy fraction from one or more intermediate separation stages B _j carried out between two consecutive additional hydroconversion stages ( a _i );
• part of the liquid effluent from one or more additional hydroconversion stages ( a _i );
• a portion of one or more of the intermediate cuts from the first fractionation step (c) ;
• a portion of the DAO produced in the deasphalter D in the deasphalting step (d) ;
• a part of the heavy fraction of the DAO produced in the second fractionation step (e) ;
• part or all of the light fraction of the DAO produced in the second fractionation step (e).

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

Deasphalting step ( d )

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

• une partie de la charge lourde hydrocarbonée envoyée à l'étape d'hydroconversion (bypass);
• une ou plusieurs charges d'hydrocarbures externes de préférence des coupes d'hydrocarbures externes au procédé, telles que des distillats atmosphériques, des distillats sous vide, des résidus atmosphériques, des résidus sous vide ;
• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires (b _j ) réalisées entre deux étapes d'hydroconversion supplémentaires consécutives (a _i ) (non représenté à la figure 1) ;
• une partie de l'effluent liquide de l'étape initiale d'hydroconversion (a ₁) ou d'une ou plusieurs étapes d'hydroconversion supplémentaires (a _i ) (non représenté à la figure 1) ;

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

• part of the heavy hydrocarbon feed sent to the hydroconversion stage (bypass);
• one or more feedstocks of external hydrocarbons, preferably hydrocarbon cuts external to the process, such as atmospheric distillates, vacuum distillates, atmospheric residues, vacuum residues;
• part of the heavy fraction from one or more intermediate separation stages ( b _j ) carried out between two consecutive additional hydroconversion stages ( a _i ) (not shown in figure 1 );
• part of the liquid effluent from the initial hydroconversion stage ( a ₁ ) or from one or more additional hydroconversion stages ( a _i ) (not shown in figure 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. One can thus refer to the article of Billon and others published in 1994 in volume 49, N°5 of the Revue de l'Institut Français du Pétrole, pages 495 to 507 , to the book " Refining and conversion of heavy petroleum products" by JF Le Page, SG Chatila and M Davidson, Technip Edition, page 17 - 32 or patents US 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 between 60°C and 250°C with at least one hydrocarbon solvent. The solvents used for deasphalting are low boiling point solvents, preferably paraffinic solvents, and preferably heavier than propane, and preferably having 3 to 7 carbon atoms. Preferred solvents include propane, butane, isobutane, pentane, isopentane, neopentane, hexane, isohexanes, C ₆ hydrocarbons, heptane, C ₇ hydrocarbons, light gasolines more or less apolar, as well as the mixtures obtained from the aforementioned solvents. Preferably, the solvent is butane, pentane or hexane, as well as their mixtures. The solvent or solvents are optionally added with at least one additive. The solvents which can be used and the additives are widely described in the literature. The solvent/feed (volume/volume) ratios entering 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 opticcritical process, that is to say by using a solvent under supercritical conditions in the separation section. This method makes it possible in particular to significantly improve the overall economy of the method.

In the context of the present invention, it is preferred to implement a technique using at least one extraction column and preferably only one (for example the Solvahl ^™ process). Advantageously, as in the Solvahl ^™ process with a single extraction column, the solvent/feed (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 a preferred implementation, the deasphalting is carried out in an extraction column at a temperature between 60° C. and 250° C. with at least one hydrocarbon solvent having from 3 to 7 carbon atoms, and a solvent / charge ratio (volume/volume) between 4/1 and 6/1.

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

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

Table 1 below gives the ranges of typical operating conditions for deasphalting depending on the solvent: <b>Table 1</b> Solvent Propane Butane pentane Hexane Heptane Pressure, MPa 3-5 3-4 2-4 2-4 2-4 Temperature, °C 45 - 110 80 - 160 140 - 210 150 - 230 160 - 280 Solvent/Filler Ratio, v/v 6-10 5-8 3-6 3-6 3-6

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

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

The DAO obtained advantageously has a content of C ₇ asphaltenes of less than 2% by weight in general, preferably of less than 0.5% by weight, preferably of less than 0.05% by weight measured of C ₇ insolubles.

In accordance with the invention, the DAO thus produced is either sent to a second fractionation stage (e) of the process according to the invention, or recycled at least in part to one or more of the intermediate separation stages ( b _j ) and/ or directly at the entrance to one or more additional hydroconversion stages ( a _i ), and more preferably at the entrance to the last additional hydro conversion stage ( a _n ).

Second fractionation step (e) - 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 fractionating section E can thus comprise one or more following separation equipment: one or more flash drums arranged in series, and preferably a sequence of at least two successive flash drums, 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 carried out by linking at least two successive flash balloons.

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

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

According to another preferred implementation, this second fractionation step (e) is carried out by a vacuum column.

The choice of the equipment of the splitting section E preferably depends on the choice of the equipment of the first splitting section C and of the loads 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 several additional hydroconversion steps ( a _i ), and more preferably at the inlet of the last additional hydroconversion step ( a _n ).

According to a preferred implementation, the heavy cut 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 avoids the concentration of sediments and rapid fouling of the vacuum distillation column. The atmospheric residue thus produced is then sent to the deasphalter D to operate the deasphalting stage (d), producing a residual asphalt and a DAO practically free of C ₇ asphaltenes and sediments, but containing both a fraction of distillate under vacuum and a residue fraction under vacuum. This DAO thus obtained can then be sent to the second fractionation section E of the process according to the invention, consisting of a vacuum distillation column and having the objective of separating the DAO into at least one light fraction of the DAO whose boiling point is predominantly below 500°C and at least one heavy fraction of the DAO whose boiling point is predominantly above 500°C. As the DAO produced in Deasphalter D is sediment-free and contains virtually no 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 at the inlet of the last additional hydroconversion stage ( a _n ).

The process according to the invention therefore improves the stability of the liquid effluents treated during the hydroconversion, and more particularly during the additional hydroconversion stages receiving at least a part of the DAO and/or of the heavy fraction of the DAO, while by considerably increasing the conversion of the heavy hydrocarbon feedstock.

DAO or DAO heavy fraction recycling step (f)

The process according to the invention comprises the recycling of at least part of the DAO resulting from stage (d) and/or of at least a part of the heavy fraction of the DAO resulting from stage (e) to an additional hydroconversion step ( a _i ) and/or to an intermediate separation step ( b _j ).

This recycling was previously described in relation to the deasphalting (d) and second fractionation (e) stages.

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

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

According to one implementation, the method comprises the recycling ( r ₁ ) of part or all of the light fraction of the DAO from step (e) in the initial hydroconversion section A ₁ and/or in at least one additional hydroconversion section A _i and/or in at least one intermediate separation section B _j and/or in the first fractionation section C.

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

According to one implementation, the method comprises the recycling ( r ₃ ) of part of the DAO resulting from step (d) in the first fractionation section C.

According to one implementation, the method comprises the recycling ( r ₄ ) of part or all of the residual asphalt resulting from step (d) in the initial hydroconversion section A ₁ and/or in at least one additional hydroconversion section A _i . Preferably, the residual asphalt is recycled in a hydroconversion section different from that which receives the DAO or the heavy fraction of the DAO.

• dans la section d'hydroconversion initiale A₁ , et/ou
• dans une autre section d'hydroconversion supplémentaire A _i positionnée en amont de ladite section A _i donnée, et/ou
• dans une section de séparation intermédiaire B _j positionnée en amont de ladite section A _i donnée.

According to one implementation, the process comprises the recycling ( r ₅ ) of part of the hydroconverted liquid effluent from a given additional hydroconversion section A _i :

• in the initial hydroconversion section A ₁ , and/or
• in another additional hydroconversion section A _i positioned upstream of said given section A _i , and/or
• in an intermediate separation section B _j positioned upstream of said given section A _i .

• dans la section d'hydroconversion initiale A₁ , et/ou
• dans une section d'hydroconversion supplémentaire A _i positionnée en amont de ladite section intermédiaire B _j donnée, et/ou
• dans une autre section de séparation intermédiaire B _j positionnée en amont de ladite section B _j donnée.

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

• in the initial hydroconversion section A ₁ , and/or
• in an additional hydroconversion section A _i positioned upstream of said given intermediate section B _j , and/or
• in another intermediate separation section B _j positioned upstream of said given section B _j .

• dans la section d'hydroconversion initiale A₁ , et/ou
• dans une section d'hydroconversion supplémentaire A _i , et/ou
• dans une section de séparation intermédiaire B _j .

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

• in the initial hydroconversion section A ₁ , and/or
• in an additional hydroconversion section A _i , and/or
• in an intermediate separation section B _j .

The following embodiments are described with reference to the corresponding figures

The figure 1 schematically represents the general case of the method according to the invention, including different options corresponding to different embodiments.

According to the process illustrated in figure 1 , the heavy hydrocarbon charge 1 is sent via a pipe to an initial hydroconversion section A ₁ composed of one or more three-phase reactors, which can be in series and/or in parallel. These hydroconversion reactors can be reactors of the bubbling bed and/or hybrid bed type, depending on the feed to be treated, and are preferably reactors operating in a bubbling bed.

The initial hydroconversion step carried out in section A ₁ represents the first hydroconversion step of the heavy hydrocarbon feedstock 1, and may include the co-treatment of one or more external feedstocks 2 and/or one or more recycle effluents from other stages of the process.

• une partie de l'effluent total (6, 10) issu d'une ou plusieurs sections d'hydroconversion supplémentaires A _i ;
• une partie ou la totalité d'une ou plusieurs fractions intermédiaires issues d'une ou plusieurs sections de séparation intermédiaires B_j (non représenté à la figure 1) ;
• une partie de la fraction lourde issue d'une ou plusieurs sections de séparation intermédiaires B_j ;
• une partie ou la totalité d'une ou plusieurs coupes intermédiaires 12 issues de la première section de fractionnement C ;
• une partie de la coupe lourde 13 issue de la première section de fractionnement C ;
• une partie ou la totalité de l'asphalte résiduel 14 issu du désasphalteur D ;
• une partie ou la totalité de la fraction légère 16 de la DAO issue de la deuxième section de fractionnement E.

The various recycle effluents which can be injected into section A ₁ are as follows:

• a portion of the total effluent (6, 10) from one or more additional hydroconversion sections A _i ;
• part or all of one or more intermediate fractions from one or more intermediate separation sections B _j (not shown in figure 1 );
• part of the heavy fraction from one or more intermediate separation sections B _j ;
• part or all of one or more intermediate cuts 12 from the first splitting section C ;
• a part of the heavy cut 13 from the first splitting section C ;
• some or all of the residual asphalt 14 from the deasphalter D ;
• part or all of the light fraction 16 of the DAO from the second fractionation section E.

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

• une partie de l'effluent total (6, 10) issu d'une ou plusieurs sections d'hydroconversion supplémentaires A_i ;
• une partie ou la totalité d'une ou plusieurs fractions intermédiaires issues d'une ou plusieurs sections de séparation intermédiaires B _j (non représenté à la figure 1) ;
• une partie de la fraction lourde 9 issue d'une ou plusieurs sections de séparation intermédiaires B_j en aval ;
• une partie ou la totalité d'une ou plusieurs coupes intermédiaires 12 issues de la première section de fractionnement C ;
• une partie de la coupe lourde 13 issue de la première section de fractionnement C ;
• une partie ou la totalité de la DAO 15 issue du désasphalteur D ;
• une partie ou la totalité de la fraction légère de la DAO 16 issue de la deuxième section de fractionnement E ;
• une partie ou la totalité de la fraction lourde de la DAO 17 issue de la deuxième section de fractionnement E.

Section B ₁ represents the first intermediate separation section where the intermediate separation step ( b ₁ ) takes place. It receives part or all of the liquid effluent from the previous hydroconversion step A ₁ , possibly with an injection of a heavy hydrocarbon feed 1 and/or an injection of one or more external feeds 2 and/or an injection of one or more recycle effluents. The different recycle effluents that can be injected into section B ₁ are:

• a portion of the total effluent (6, 10) from one or more additional hydroconversion sections A _i ;
• part or all of one or more intermediate fractions from one or more intermediate separation sections B _j (not shown in figure 1 );
• part of the heavy fraction 9 from one or more intermediate separation sections B _j downstream;
• part or all of one or more intermediate cuts 12 from the first splitting section C ;
• a part of the heavy cut 13 from the first splitting section C ;
• part or all of the DAO 15 from the deasphalter D ;
• part or all of the light fraction of the DAO 16 from the second fractionation section E ;
• part or all of the heavy fraction of the DAO 17 from the second fractionation section E.

The heavy fraction 5 from the first intermediate separation section B ₁ is then sent at least in part 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 part or all 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 A ₁ .

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

• une partie de l'effluent total 10 d'une ou plusieurs sections d'hydroconversion supplémentaires A_i en aval ;
• une partie ou la totalité d'une ou plusieurs fractions intermédiaires issues d'une ou plusieurs sections de séparation intermédiaires B_j en aval (non représenté à la figure 1) ;
• une partie de la fraction lourde 9 issue d'une ou plusieurs sections de séparation intermédiaires B_j en aval ;
• une partie ou la totalité d'une ou plusieurs coupes intermédiaires 12 issues de la première section de fractionnement C ;
• une partie de la coupe lourde 13 issue de la première section de fractionnement C ;
• une partie ou la totalité de la DAO 15 issue du désasphalteur D ;
• une partie ou la totalité de l'asphalte résiduel 14 issu du désasphalteur D ;
• une partie ou la totalité de la fraction légère de la DAO 16 issue de la deuxième section de fractionnement E ;
• une partie ou la totalité de la fraction lourde 17 de la DAO issue de la deuxième section de fractionnement E.

This section A ₂ can receive part or all of the liquid effluent from the initial hydroconversion section A ₁ and/or at least part of the heavy fraction from the first intermediate separation section B ₁ . This section A ₂ can also receive part of the heavy hydrocarbon feed 1 and/or one or more additional feeds 2 and/or one or more recycle effluents for co-treatment. The various recycle effluents which can be injected into section A ₂ are:

• a portion of the total effluent 10 from one or more additional hydroconversion sections A _i downstream;
• part or all of one or more intermediate fractions from one or more intermediate separation sections B _j downstream (not shown in figure 1 );
• part of the heavy fraction 9 from one or more intermediate separation sections B _j downstream;
• part or all of one or more intermediate cuts 12 from the first splitting section C ;
• a part of the heavy cut 13 from the first splitting section C ;
• part or all of the DAO 15 from the deasphalter D ;
• some or all of the residual asphalt 14 from the deasphalter D ;
• part or all of the light fraction of the DAO 16 from the second fractionation section E ;
• part or all of the heavy fraction 17 of the DAO from the second fractionation section E.

The liquid effluent 6 from the second hydroconversion section A ₂ can 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 therefore of sending either all or only part of said effluent from section A ₂ to second intermediate separation section B ₂ (not shown), as well as recycling part of said effluent to one or more hydroconversion sections upstream from section A ₂ or towards the intermediate separation section B ₁ situated between sections A ₁ and A ₂ .

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

• une partie de l'effluent 10 de la dernière section d'hydroconversion A _n ;
• une partie ou la totalité d'une ou plusieurs coupes intermédiaires (12) issues de la première section de fractionnement C ;
• une partie de la coupe lourde issue de la première section de fractionnement C ;
• une partie ou la totalité de la DAO 15 issue du désasphalteur D ;
• une partie ou la totalité de la fraction légère de la DAO 16 issue de la deuxième section de fractionnement E ;
• une partie ou la totalité de la fraction lourde de la DAO 17 issue de la deuxième section de fractionnement E.

Section B _j=n-1 represents the last intermediate separation section. It receives part or all of the liquid effluent 7 from the previous hydroconversion step A _i=n-1 , and optionally an injection of a heavy load of hydrocarbons 1 and/or an injection of one or more external loads 2 and/or an injection of one or more recycle effluents. The different recycle effluents that can be injected into section B _j=n-1 are:

• part of the effluent 10 from the last hydroconversion section A _n ;
• part or all of one or more intermediate cuts (12) from the first splitting section C ;
• part of the heavy cut from the first fractionation section C ;
• part or all of the DAO 15 from the deasphalter D ;
• part or all of the light fraction of the DAO 16 from the second fractionation section E ;
• part or all of the heavy fraction of the DAO 17 from the second fractionation section E.

Section A _n represents the last hydroconversion step where the additional hydroconversion step ( a _n ) is carried out. Section A _n is made up of one or more three-phase reactors, which can be in series and/or in parallel. These hydroconversion reactors can be boiling bed and/or hybrid bed reactors, depending on the feed to be treated, and are preferably reactors operating in a boiling bed.

• une partie ou la totalité d'une ou plusieurs coupes intermédiaires 12 issues de la première section de fractionnement C ;
• une partie de la coupe lourde issue 13 issue de la première section de fractionnement C ;
• une partie ou la totalité de l'asphalte résiduel 14 issu du désasphalteur D ;
• une partie ou la totalité de la DAO 15 issue du désasphalteur D ;
• une partie ou la totalité de la fraction légère de la DAO 16 issue de la deuxième section de fractionnement E ;
• une partie ou la totalité de la fraction lourde de la DAO 17 issue de la deuxième section de fractionnement E.

This section A _n can receive part or all of the effluent from the preceding hydroconversion stage A _n-1 and/or the heavy fraction of the preceding intermediate separation section B _j=n-1 . This section A _n can also receive part of the heavy hydrocarbon feed 1 and/or one or more external feeds 2 and/or one or more recycle effluents for co-treatment. The different recycle effluents that can be injected into section A _n are:

• part or all of one or more intermediate cuts 12 from the first splitting section C ;
• a part of the heavy cut 13 from the first fractionation section C ;
• some or all of the residual asphalt 14 from the deasphalter D ;
• part or all of the DAO 15 from the deasphalter D ;
• part or all of the light fraction of the DAO 16 from the second fractionation section E ;
• part or all of the heavy fraction of the DAO 17 from the second fractionation section E.

Section C represents the first fractionation section in which all or at least part of the hydroconverted liquid effluent 10 from the last hydroconversion section A _n is sent via a pipe to be split into several cuts. For example, the figure 1 represents three cuts, a light cut 11, which comes out of the process according to the invention and which is optionally sent to post-processing, an intermediate cut 12 and a heavy cut 13. These last two cuts can be partially or totally sent to d 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.

• une partie de la fraction lourde issue d'une ou plusieurs étapes de séparation intermédiaires B _j (non représentée à la figure 1) ;
• une partie de l'effluent liquide d'une ou plusieurs étapes d'hydroconversion (a ₁ et a _i) (non représentée à la figure 1) ;
• une partie de la DAO 15 produite dans le désasphalteur D ;
• une partie de la fraction lourde de la DAO 17 produite dans la deuxième section de fractionnement E ;
• une partie ou la totalité de la fraction légère 16 de la DAO produite dans la deuxième étape de fractionnement E.

The first fractionation section C can also receive, either at the inlet or between two different pieces of equipment making up this section C, part of the heavy hydrocarbon load 1 and/or external loads 2 and/or one of the following recycle effluents:

• part of the heavy fraction from one or more intermediate separation stages B _j (not shown in figure 1 );
• part of the liquid effluent from one or more hydroconversion stages ( a ₁ and a _i ) (not shown in figure 1 );
• part of the DAO 15 produced in the deasphalter D ;
• part of the heavy fraction of the DAO 17 produced in the second fractionation section E ;
• part or all of the light fraction 16 of the DAO produced in the second fractionation step E.

• une partie de la fraction lourde issue d'une ou plusieurs sections de séparation intermédiaires B) (non représenté à la figure 1) ;
• une partie de l'effluent liquide issu de la section initiale d'hydroconversion A ₁ ou d'une ou plusieurs sections d'hydroconversion supplémentaires A_i (non représenté à la figure 1) ;

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 part of the heavy cut 13 from the first fractionation section C The deasphalter D can also receive part of the heavy hydrocarbon load 1 and/or additional loads 2 and/or one of the following recycle effluents:

• part of the heavy fraction from one or more intermediate separation sections B) (not shown in figure 1 );
• part of the liquid effluent from the initial hydroconversion section A ₁ or from one or more additional hydroconversion sections A _i (not shown in figure 1 );

The DAO produced in the deasphalter D can either be sent, in part or totally, to the second fractionation section E, or recycled, in part or totally, to one or more of the additional hydroconversion sections A _i and/or to one or more of the intermediate separation sections B _j .

Section E represents a second splitting section of the method according to the invention in which step (e) of splitting all or at least part of the DAO into at least two sections is carried out. For example, the process illustrated in figure 1 shows two cuts, a light cut 16, which can come out of the process according to the invention and/or be recycled in different sections of the process as previously described, and a heavy cut 17. The latter can then be partially or totally recycled in one or more several additional hydroconversion sections A _i and/or recycled on one or on several intermediate separation sections B _j .

The light cut 16 can for example, in part or in whole, be used to produce heavy fuel oils, such as bunker fuel oils. The light cut 16 can also, in part or in whole, be sent to a conversion stage operating with a process chosen from the group formed by fixed-bed hydrocracking, fluidized-bed catalytic cracking, bubbling-bed hydroconversion , these processes possibly comprising a prior hydrotreatment.

According to a preferred embodiment, part or all of the light cut 16 of the deasphalted DAO fraction is subjected to fixed-bed hydrocracking, in the presence of hydrogen, under an absolute pressure of between 5 MPa and 35 MPa, at a temperature advantageously comprised between 300 and 500° C., a WH comprised between 0.1 h ^-1 and 5 h ^-1 , and a quantity of hydrogen comprised 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 from non-noble group VIII and at least one element from group VIB and comprising a support containing at minus one zeolite.

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

According to another preferred mode, part or all of the light cut 16 of the deasphalted fraction DAO is subjected to bubbling bed hydroconversion, carried out in the presence of hydrogen, under 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 between 0.1 h ^-1 and 10 h ^-1 and in presence of a catalyst containing a support and at least one metal from group VIII chosen from nickel and cobalt and at least one metal from group VIB chosen from molybdenum and tungsten.

Circuit 18 dotted on the figure 1 represents the multiple possible catalyst exchanges between the different hydroconversion steps, as well as the purging and addition of fresh and spent catalysts.

Four preferred implementations of the general scheme of the figure 1 are illustrated in figures 2 to 5 by increasingly limiting the number of equipment and thus the investment costs.

The figure 2 illustrates the invention in a preferred implementation comprising the recycling of the heavy fraction of the DAO at the inlet of the last hydroconversion step.

According to this implementation, the method comprises the following successive steps: the initial hydroconversion step ( a ₁ ), the intermediate separation step ( b ₁ ), a second hydroconversion step ( a ₂ ) which is the only additional hydroconversion step, the first fractionation step (c), the deasphalting step (d) and the second fractionation step (e).

The heavy hydrocarbon charge 1 is sent via a pipe into the initial hydroconversion section A ₁ at high hydrogen pressure 19. The section A ₁ is identical to that described in relation to the figure 1 .

The liquid effluent 3 from section A ₁ is separated in intermediate separation section B ₁ . In the separation section B ₁ , the conditions are generally chosen so as to obtain two liquid fractions, a light fraction 4 and a heavy fraction 5. The section can comprise any means of separation known to those skilled in the art, and preferably does not comprise either an atmospheric distillation column or a vacuum distillation column, but a vapor or hydrogen stripping column, and is constituted more preferably by a sequence of flash drums, and even more preferably by a single flash balloon.

The heavy liquid fraction 5 at the outlet of the intermediate separation section B ₁ is then sent via a pipe to the second hydroconversion stage A ₂ at high hydrogen pressure 20. This section A ₂ conforms to the description of the section of initial hydroconversion A ₁ of the 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 cut 13. The section preferably includes a set of flash drums and an atmospheric distillation column.

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

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. Section E comprises preferably a set of flash flasks and a vacuum distillation column.

The heavy fraction of the DAO 17 is then mixed, in part or in whole 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 .

The picture 3 illustrates the invention in another implementation involving the recycling of the DAO in the intermediate separation section.

According to this implementation, the method comprises the following successive steps: the initial hydroconversion step ( a ₁ ), the intermediate separation step ( b ₁ ), a second hydroconversion step ( a ₂ ) which is the one additional hydroconversion step, the first fractionation step (c), and the deasphalting step (d). There is no second splitting step (e).

The heavy hydrocarbon charge 1 is sent via a pipe to an initial hydroconversion section A ₁ at high hydrogen pressure 19. Section A ₁ is identical to that described in relation to the figure 1 .

The liquid effluent 3 from the section A ₁ is separated in the intermediate separation section B ₁ at the same time as the DAO 15 recycled from the deasphaltor D. In the intermediate separation section B ₁ , the conditions are chosen so as to obtain two liquid fractions, a light fraction 4 and a heavy fraction 5. Section B ₁ may include any means of separation known to those skilled in the art, and preferably does not include either an atmospheric distillation column or a 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 balloon.

The heavy liquid fraction 5 at the outlet of the intermediate separation section B ₁ is then sent to the second hydroconversion section A ₂ at high hydrogen pressure 20. This section A ₂ conforms to the description of the hydroconversion section initial A ₁ of the 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 cut 13. The section preferably involves using a set of flash flasks and an atmospheric distillation column.

The heavy cut 13 is then sent via a pipe to 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 pipe.

The DAO is then mixed, in part or in whole 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 B ₁ .

The figure 4 illustrates the invention in another preferred implementation comprising the recycling of the DAO at the inlet of the last hydroconversion step.

According to this implementation, the method comprises the following successive steps: the initial hydroconversion step ( a ₁ ), the intermediate separation step ( b ₁ ), a second hydroconversion step ( a ₂ ) which is the one additional hydroconversion step, the first fractionation step (c), and the deasphalting step (d). There is no second splitting step (e).

The heavy hydrocarbon charge 1 is sent via a pipe to an initial hydroconversion section A ₁ at high hydrogen pressure 19. Section A ₁ is identical to that described in relation to the figure 1 .

The liquid effluent 3 from section A ₁ is separated in intermediate separation section B ₁ . 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 can comprise any means of separation 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 preferred by a sequence of flash balloons, and even more preferably by a single flash balloon.

The heavy liquid fraction 5 at the outlet of the intermediate separation section B ₁ is then sent via a pipe to the second hydroconversion stage A ₂ at high hydrogen pressure 20. This section A ₂ conforms to the description of the section of initial hydroconversion A ₁ of the 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 cut 13. The section preferably comprises a set of flash drums and atmospheric and vacuum distillation columns.

The heavy cut 13 is then sent via a pipe to the deasphalter D to obtain a 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 is then mixed, in part or in whole as shown, with the heavy liquid fraction 5 coming from the intermediate separation section B ₁ and the mixture is then sent to the second hydroconversion section A ₂ .

The figure 5 illustrates the invention in another implementation not comprising any intermediate separation step.

According to this implementation, the method comprises the following successive steps: the initial hydroconversion step ( a ₁ ), a second hydroconversion step ( a ₂ ) which is the only additional hydroconversion step, the first step of fractionation (c), and the deasphalting step (d). There is no second splitting step (e).

The heavy hydrocarbon charge 1 is sent via a pipe to an initial hydroconversion section A ₁ at high hydrogen pressure 19. Section A ₁ is identical to that described in relation to the figure 1 .

The liquid effluent 3 from section A ₁ is then sent via a pipe to the second hydroconversion section A ₂ at high hydrogen pressure 20. This section A ₂ conforms to the description of the initial hydroconversion section At ₁ of the figure 1 .

The hydroconverted liquid effluent 6 obtained at the end of this second hydroconversion step 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 cut 13. The section preferably comprises using a set of flash drums and atmospheric and vacuum distillation columns.

The heavy cut 13 is then sent via a pipe to 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 whole as shown, with the liquid effluent 3 from the initial hydroconversion section A ₁ , 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 its scope, and some of its performances, 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 heavy hydrocarbon charge is a vacuum residue (RSV) originating from a Ural crude oil, the main characteristics of which are presented in Table 2 below. <b>Table 2</b> Charge of the first stage of hydroconversion ( a ₁ ) / (a' ₁ ) / (a" ₁ ) Charge RSV Urals Content at 540°C+ %weight 84.7 Viscosity at 100°C cSt 880 Density 1.0090 Carbon Conradson %weight 17.0 C ₇ Asphaltenes %weight 5.5 Nickel + Vanadium ppm weight 254 Nitrogen %weight 0.615 Sulfur %weight 2,715

This RSV heavy load is the same fresh load for the different examples.

Example. 1: Method of. reference without recycling of / a DAO. (not according to the invention)

This example illustrates a process for the hydroconversion of a heavy charge of hydrocarbons according to the state of the art comprising two successive hydroconversion stages each comprising a reactor operating in an ebullated bed, followed by a deasphalting stage without recycling of the DAO.

First stage of hydroconversion

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A′ ₁ in the presence of hydrogen to undergo a first hydroconversion step ( a′ ₁ ), said section comprising a three-phase reactor containing a catalyst of 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 an ebullated bed operating with an ascending current of liquid and gas.

The operating conditions applied in the first hydroconversion step are presented in Table 3 below. <b>Table 3</b> First stage of hydroconversion ( a ' ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate Separation Stage

The hydroconverted liquid effluent from the first hydroconversion stage ( a′ ₁ ) is then sent to an intermediate separation section B′ ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first stage of hydroconversion. A light fraction and a so-called heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point lower than 350°C and the heavy fraction is mainly composed of molecules of hydrocarbons boiling at a temperature higher than or equal to 350°C.

The composition of this heavy fraction is shown in Table 4. <b>Table 4</b> Stage load ( a' ₂ ) Charge Heavy fraction from B' ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second hydroconversion step (a' ₂ ).

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 three-phase 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 ascending current of liquid and gas.

The operating conditions applied in the second hydroconversion step ( a′ ₂ ) are presented in Table 5 below. <b>Table 5</b> Step ( a' ₂ ) VVH reactor h ^-1 0.54 P total MPa 15.6 Temperature °C 425 Hydrogen quantity Nm ³ /m ³ 250

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

First step fractionation

The hydroconverted liquid effluent 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 distillation column under vacuum following which a distillate fraction is recovered under vacuum boiling at a temperature between essentially between 350°C and 500°C (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500°C (RSV) whose yields relative to the fresh load and product qualities are given in Table 6 below. <b>Table 6</b> DSV RSV Yield relative to fresh load %weight 35.2 29.0 Density 0.9532 1,067 Carbon Conradson %weight 1.9 > 30 C ₇ Asphaltenes %weight < 0.05 15.7 Nickel + Vanadium ppm weight <4 151 Nitrogen %weight 0.46 0.98 Sulfur %weight 0.7097 1.6887 sediments %weight < 0.01 0.20

Deasphalting step

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

• Pression totale = 3 MPa ;
• Température moyenne = 95°C ;
• Ratio solvant/charge = 8 v/v.

The operating conditions applied in the deasphalter are as follows:

• Total pressure = 3 MPa;
• Average temperature = 95°C;
• Solvent/filler ratio = 8 v/v.

At the outlet of the deasphalter, a DAO and a residual asphalt are obtained, having the characteristics given in Table 7 below. <b>Table 7</b> CAD Residual asphalt Yield %weight of SDA load 69.5 30.5 Density 0.9939 1,282 Carbon Conradson %weight 7.84 > 30 C ₇ Asphaltenes %weight 0.07 > 30 Nickel + Vanadium ppm weight < 4 490 Nitrogen %weight 0.52 2.0 Sulfur %weight 1,049 3,146

Overall performance

With this conventional process, not in accordance with the invention, the overall conversion of the 540° C.+ fraction of the fresh charge is 64.0% by weight. The unconverted vacuum residue fraction contains 0.20% by weight of sediments, 150 ppm by weight of metals and a Conradson Carbon content greater than 30% by weight. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable 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 more metals or asphaltenes and its Conradson Carbon content is less than 8% by weight. This DAO cut can therefore be sent, in part or in whole, to another conversion stage such as fixed bed hydrocracking, fixed bed hydrotreating, fluidized bed catalytic cracking, or bubbling bed hydroconversion .

Example 2: Reference process. with recycling of the DAO at the inlet of the first, hydroconversion stage (not in accordance with the invention)

In this example 2, the state of the art is illustrated in a process for the hydroconversion of a heavy charge of hydrocarbons comprising two successive hydroconversion stages each comprising a reactor operating in an ebullated bed, followed by a stage of deasphalting with recycling of the DAO at the entrance to the first hydroconversion stage.

First stage of hydroconversion

The fresh load from Table 2 is first mixed with the DAO from the deasphalting stage ( d" ) in a fresh load/DAO volume ratio equal to 75/25. This mixture is then sent in its entirety to a first section of hydroconversion A " ₁ in the presence of hydrogen to undergo a first hydroconversion step ( a " ₁ ). This section A " ₁ is identical to that described in example 1.

The conditions applied in this first hydroconversion section A " ₁ are presented in Table 8 below. <b>Table 8</b> Step (a" ₁ ) VVH reactor h ^-1 0.80 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

The increase in the reactor VVH, compared to the VVH during the first hydroconversion step according to example 1, is due to the recycling of the DAO, the flow rate of fresh feed being kept constant. These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced content of Conradson carbon, metals and sulfur. The conversion per pass 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" ₁ ) is then sent to an intermediate separation section B" ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion step. A light fraction and a heavy fraction are thus separated. The light fraction is mainly composed of molecules with a boiling point below 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. <b>Table 9</b> Stage load (a" ₂ ) load Heavy fraction from B" ₁ Density 0.9747 Carbon Conradson %weight 9.3 C ₇ Asphaltenes %weight 3.6 Nickel + Vanadium ppm weight 70 Nitrogen %weight 0.49 Sulfur %weight 1.1380

Second stage of hydroconversion

The heavy fraction, the composition of which is given in Table 9, is sent in its entirety to a second hydroconversion section A″ ₂ in the presence of hydrogen to undergo a second hydroconversion stage (a″ ₂ ). This section A" ₂ is identical to that described in example 1.

The operating conditions applied during this second hydroconversion step (a" ₂ ) are presented in Table 10 below. <b>Table 10</b> Step (a" ₂ ) VVH reactor h ^-1 0.72 P total MPa 15.6 Temperature °C 425 Hydrogen quantity Nm ³ /m ³ 250

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

First step fractionation

The hydroconverted liquid effluent 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 following which a distillate fraction under vacuum boiling at a temperature essentially between 350°C and 500°C (DSV) and an unconverted residue fraction under vacuum boiling mainly at a temperature greater than or equal to 500°C are recovered (RSV) whose yields in relation to the fresh load and product qualities are given in Table 11 below. <b>Table 11</b> DSV RSV Yield relative to fresh load %weight 36.8 34.4 Density 0.9383 1,039 Carbon Conradson %weight 0.8 21 C ₇ Asphaltenes %weight < 0.05 6.3 Nickel + Vanadium ppm weight <4 74 Nitrogen %weight 0.38 0.66 Sulfur %weight 0.4292 1.0408 sediments %weight < 0.01 0.34

Deasphalting stage

The RSV from the first fractionation section C ″ is then advantageously sent to a deasphalting stage (d″) in a deasphalting device D ″, in which it is treated as described in example 1 (same equipment and same conditions).

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 12 below are obtained. <b>Table 12</b> CAD Residual asphalt Yield %weight of SDA load 73.9 26.1 Density 0.9729 1,286 Carbon Conradson %weight 4.4 > 30 C ₇ Asphaltenes %weight < 0.05 24 Nickel + Vanadium ppm weight < 4 281 Nitrogen %weight 0.33 1.6 Sulfur %weight 0.6689 2,094

After deasphalter D, 26% of the DAO produced is purged, while the rest of the DAO is sent upstream of the first hydroconversion stage ( a″ ₁ ).

Overall performance

With this conventional process comprising a recycling of the DAO at the inlet of the first hydroconversion stage, not in accordance with the invention, the conversion by pass of the 540° C.+ fraction of the fresh feed in the section of hydroconversion is 55.9% by weight. The unconverted vacuum residue fraction contains 0.34% by weight of sediment, 74 ppm by weight of metals and a Conradson Carbon content of 21% by weight. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable 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 more metals or asphaltenes and its Conradson Carbon content is less than 5% by weight. In this diagram not in accordance with the invention, a large fraction of this DAO cut (74%) is recycled at the inlet of the first reactor of the hydroconversion section. Thanks to recycling, the overall conversion of the 540° C.+ fraction of the fresh feed is 69.7% by weight.

Example 3: Process according to the invention, aimed at reducing the sediment content of the unconverted vacuum residue

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 an ebullated bed followed by a deasphalting stage with recycling of the DAO at the inlet of the last hydroconversion reactor.

First stage of hydroconversion.

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A ₁ in the presence of hydrogen to undergo a first hydroconversion step ( a ₁ ). This section A ₁ is identical to that described in example 1.

The operating conditions applied to this first hydroconversion step ( a ₁ ) are presented in Table 13 below. <b>Table 13</b> Step ( has ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate separation step

The hydroconverted liquid effluent is then sent to an intermediate separation section B ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor 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 below 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. <b>Table 14</b> Charge Heavy fraction from B ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second, hydroconversion step

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B ₁ is completely mixed with the DAO from the deasphalting step ( d ) in a heavy effluent/DAO volume ratio of 75 /25. The composition of this filler is shown in Table 15. <b>Table 15</b> Stage load (a ₂ ) Density 0.9854 Carbon Conradson %weight 10.4 C ₇ Asphaltenes %weight 3.7 Nickel + Vanadium ppm weight 60 Nitrogen %weight 0.54 Sulfur %weight 1.2186

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

The operating conditions applied in the hydroconversion stage ( a ₂ ) are presented in Table 16 below. <b>Table 16</b> Step (a ₂ ) VVH reactor h ^-1 0.72 P total MPa 15.6 Temperature °C 425 Hydrogen quantity Nm ³ /m ³ 250

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

First split section

The hydroconverted liquid effluent 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 vacuum distillation column at the following which a vacuum distillate fraction boiling at a temperature essentially between 350° C. and 500° C. (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500° C. (RSV) are recovered. Returns relative to fresh feed and product grades are given from this first fractionation section are shown in Table 17 below. <b>Table 17</b> DSV RSV Yield relative to fresh load %weight 36.4 33.9 Density 0.9483 1,048 Carbon Conradson %weight 0.9 24 C ₇ Asphaltenes %weight < 0.05 7.2 Nickel + Vanadium ppm weight <4 63 Nitrogen %weight 0.44 0.75 Sulfur %weight 0.6113 1.1141 sediments %weight <0.01 0.07

Comparing with Example 1, a higher level of hydrotreating is observed with a lower density, lower sulfur, nitrogen, metals, asphaltenes and Conradson carbon contents. In addition, RSV contains less sediment and is therefore more stable, in particular thanks to the presence of heavy aromatics from the recycled DAO upstream of the second hydroconversion step.

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

Deasphalting stage

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

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 18 below are obtained. <b>Table 18</b> CAD Residual asphalt Yield %weight of SDA load 73.5 26.5 Density 0.9832 1,282 Carbon Conradson %weight 4.8 > 30 C ₇ Asphaltenes %weight < 0.05 27 Nickel + Vanadium ppm weight < 4 235 Nitrogen %weight 0.37 1.8 Sulfur %weight 0.6976 2,269

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

Overall performance

According to the process of the invention illustrated in this example, comprising recycling of the DAO to the last hydroconversion step, the conversion per pass of the 540° C.+ fraction of the fresh feed from the hydroconversion section is 61.5% by weight. The unconverted vacuum residue fraction contains 0.07% by weight of sediment, 63 ppm by weight of metals and a Conradson Carbon content of 24% by weight. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable 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 more 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 DAO cut (74%) is recycled at the inlet of the last reactor of the hydroconversion section. Thanks to recycling, the overall conversion of the 540° C.+ fraction of the fresh feed is 69.5% by weight.

It is therefore noted that, compared to example 1, the conversion is stronger (5.5 conversion points more) and that the RSV which leaves 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 their cleaning.

Example 4: Process according to the invention , aimed at increasing the overall conversion of the 540° C.+ fraction

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 an ebullated bed followed by a deasphalting stage with recycling of the DAO at the inlet of the last hydroconversion reactor. As the sediment content is reduced in the process according to the invention, this latter reactor will be operated under more severe conditions in order to increase the overall conversion of the process.

First stage of hydroconversion

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A ₁ in the presence of hydrogen to undergo a first hydroconversion step ( a ₁ ). This section A ₁ is identical to that described in example 1.

The operating conditions applied to this first hydroconversion step ( a ₁ ) are presented in Table 19 below. <b>Table 19</b> Step (a ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate separation stage

The hydroconverted liquid effluent is then sent to an intermediate separation section B ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor 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 below 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. <b>Table 20</b> Charge Heavy fraction from B ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second stage of hydroconversion

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B ₁ is completely mixed with the DAO from the deasphalting step ( d ) in a heavy effluent/DAO volume ratio of 75 /25. The composition of this filler is shown in Table 21. <b>Table 21</b> Stage load (a ₂ ) Density 0.9865 Carbon Conradson %weight 10.6 C ₇ Asphaltenes %weight 3.7 Nickel + Vanadium ppm weight 60 Nitrogen %weight 0.55 Sulfur %weight 1.2324

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

The operating conditions applied in the hydroconversion stage ( a ₂ ) are presented in Table 22 below. Compared to the other examples, the reaction temperature was increased by 5°C. <b>Table 22</b> Step (a ₂ ) VVH reactor h ^-1 0.72 P total MPa 15.6 Temperature °C 430 Hydrogen quantity Nm ³ /m ³ 250

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

First split section

The hydroconverted liquid effluent 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 vacuum distillation column at the following which a vacuum distillate fraction boiling at a temperature essentially between 350° C. and 500° C. (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500° C. (RSV) are recovered. Yields relative to fresh feed and product qualities are given from this first fractionation section are shown in Table 23 below. <b>Table 23</b> DSV RSV Yield relative to fresh load %weight 34.9 29.1 Density 0.9496 1.055 Carbon Conradson %weight 0.8 27 C ₇ Asphaltenes %weight < 0.05 9.7 Nickel + Vanadium ppm weight <4 61 Nitrogen %weight 0.45 0.80 Sulfur %weight 0.6208 1.1862 sediments %weight <0.01 0.19

Comparing with Example 1, a higher level of hydrotreating is observed with a lower density, lower sulfur, nitrogen, metals, asphaltenes and Conradson carbon contents. Despite the higher severity, the RSV contains the same sediment content and therefore remains stable, in particular thanks to the presence of heavy aromatics from the DAO recycled upstream of the second hydroconversion step.

By 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 therefore more stable, in particular thanks to the presence of heavy aromatics from the DAO cut recycled upstream of the second hydroconversion step. In Example 2, the DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are hydrogenated more compared to the process according to the invention.

Deasphalting step

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

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in Table 24 below are obtained. <b>Table 24</b> CAD Residual asphalt Yield %weight of SDA load 72.6 27.4 Density 0.9873 1,289 Carbon Conradson %weight 5.6 > 30 C ₇ Asphaltenes %weight < 0.05 > 30 Nickel + Vanadium ppm weight < 4 220 Nitrogen %weight 0.39 1.9 Sulfur %weight 0.7529 2,334

After deasphalter D , 17% of the DAO produced 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 recycling of the DAO in the last hydroconversion step carried out under more severe conditions, a conversion is achieved per pass of the 540° C.+ fraction of the fresh charge of 64 .6% by weight in the hydroconversion section for identical operating conditions. The unconverted fraction, the vacuum residue, contains 0.19 wt% sediment, 61 wppm metals and a Conradson Carbon content of 27 wt%. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable 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 more 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 DAO cut (83%) is recycled at the inlet of the last reactor of the hydroconversion 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 to example 1, the conversion is much stronger (+10 conversion points), but that the RSV which leaves the vacuum distillation column at the first fractionation stage remains stable, because it contains approximately the same sediment content (0.19% by weight instead of 0.20% by weight). Compared to example 2, the conversion is greater (+4 conversion points), but the residual RSV still contains much less sediment (0.19% by weight instead of 0.34% by weight) and remains therefore 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 stopping for their cleaning.

Example 5: Method according to the invention, aiming to recycle the DAO cut until extinguished

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 an ebullated bed followed by a deasphalting stage with recycling of the DAO at the inlet of the last hydroconversion reactor. The DAO cut will be recycled until extinguished in order to increase the overall conversion of the process.

First stage of hydroconversion

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A ₁ in the presence of hydrogen to undergo a first hydroconversion step ( a ₁ ). This section A ₁ is identical to that described in example 1.

The operating conditions applied to this first hydroconversion step ( a ₁ ) are presented in Table 25Table 19 below. <b>Table 25</b> Step (a ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate separation step

The hydroconverted liquid effluent is then sent to an intermediate separation section B ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor 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 below 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 26. <b>Table 26</b> Charge Heavy fraction from B ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second stage of hydroconversion

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B ₁ is mixed in its entirety with the entire DAO cut resulting from the deasphalting stage ( d ). The composition of this filler is shown in Table 27. <b>Table 27</b> Stage load (a ₂ ) Density 0.9857 Carbon Conradson %weight 9.8 C ₇ Asphaltenes %weight 3.2 Nickel + Vanadium ppm weight 52 Nitrogen %weight 0.52 Sulfur %weight 1.1591

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

The operating conditions applied in the hydroconversion stage ( a ₂ ) are presented in table 28 below. As the recycling of the DAO cut is total, the _reactor VVH is greater. <b>Table 28</b> Step (a ₂ ) VVH reactor h ^-1 0.81 P total MPa 15.6 Temperature °C 430 Hydrogen quantity Nm ³ /m ³ 250

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

First split section

The hydroconverted liquid effluent 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 vacuum distillation column at the following which a vacuum distillate fraction boiling at a temperature essentially between 350° C. and 500° C. (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500° C. (RSV) are recovered. Yields relative to fresh feed and product qualities are given from this first fractionation section are shown in Table 29 below. <b>Table 29</b> DSV RSV Yield relative to fresh load %weight 35.6 31.8 Density 0.9492 1,051 Carbon Conradson %weight 0.8 25 C ₇ Asphaltenes %weight < 0.05 8.3 Nickel + Vanadium ppm weight <4 66 Nitrogen %weight 0.43 0.77 Sulfur %weight 0.5787 1.1506 sediments %weight <0.01 0.25

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

By 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 therefore more stable, in particular thanks to the presence of heavy aromatics from the DAO cut recycled upstream of the second hydroconversion step. In Example 2, the DAO is recycled upstream of the first hydroconversion stage and the heavy aromatics are hydrogenated more compared to the process according to the invention.

Deasphalting stage

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

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in table 30 below are obtained. <b>Table 30</b> CAD Residual asphalt Yield %weight of SDA load 73.3 26.7 Density 0.9851 1,287 Carbon Conradson %weight 5.2 > 30 C ₇ Asphaltenes %weight < 0.05 > 30 Nickel + Vanadium ppm weight < 4 244 Nitrogen %weight 0.38 1.8 Sulfur %weight 0.7249 2,319

After the deasphalter D , the DAO cut is sent in its entirety upstream of the last hydroconversion step.

Overall performance

According to the process of the invention illustrated in this example, comprising a recycling of the DAO in the last hydroconversion step carried out under more severe conditions, a conversion is achieved per pass of the 540° C.+ fraction of the fresh charge of 64 .6% by weight in the hydroconversion section for identical operating conditions. The unconverted fraction, the vacuum residue, contains 0.25 wt% sediment, 66 wppm metals and a Conradson Carbon content of 25 wt%. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable 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 more metals or asphaltenes and its Conradson Carbon content is only 5.2% by weight. In this scheme according to the invention, all of this DAO cut is recycled at the inlet of the last reactor of the hydroconversion section. Thanks to quenching recycling of the DAO cut, the overall conversion of the 540°C+ fraction of the fresh feed is 76.1% by weight.

It is therefore noted that, compared to Example 1, the conversion is much stronger (+12 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 (0.25% weight instead of 0.20% weight). Compared to Example 2, the conversion is greater (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 rather 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 according to the invention, allowing a longer operation before stopping for their cleaning. .

Example 6: Process according to the invention, aimed at reducing the sediment content of the unconverted vacuum residue

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 an ebullated bed followed by a deasphalting stage and a fractionation stage, with recycling of the heavy DAO at the inlet of the last hydroconversion reactor and conversion of the light DAO in an FCC unit.

First stage of hydroconversion.

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A ₁ in the presence of hydrogen to undergo a first hydroconversion stage ( a ₁ ). This section A ₁ is identical to that described in example 1.

The operating conditions applied to this first hydroconversion step ( a ₁ ) are presented in table 31 below. <b>Table 31</b> Step (a ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate separation stage

The hydroconverted liquid effluent is then sent to an intermediate separation section B ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor 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 below 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 32. <b>Table 32</b> Charge Heavy fraction from B ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second, hydroconversion step

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B ₁ is completely mixed with the heavy DAO from the second fractionation section ( e ) in a heavy effluent/DAO volume ratio of 75/25. The composition of this filler is shown in Table 33. <b>Table 33</b> Stage load (a ₂ ) Density 1.0005 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 3.6 Nickel + Vanadium ppm weight 59 Nitrogen %weight 0.57 Sulfur %weight 1.2706

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

The operating conditions applied in the hydroconversion stage ( a ₂ ) are presented in table 34 below. <b>Table 34</b> Step (a ₂ ) VVH reactor h ^-1 0.72 P total MPa 15.6 Temperature °C 425 Hydrogen quantity Nm ³ /m ³ 250

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

First split section

The hydroconverted liquid effluent 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 vacuum distillation column at the following which a vacuum distillate fraction boiling at a temperature essentially between 350° C. and 500° C. (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500° C. (RSV) are recovered. Yields relative to fresh feed and product qualities are given from this first fractionation section are shown in Table 35 below. <b>Table 35</b> DSV RSV Yield relative to fresh load %weight 31.5 39.2 Density 0.9543 1,058 Carbon Conradson %weight 1.0 28 C ₇ Asphaltenes %weight < 0.05 7.5 Nickel + Vanadium ppm weight <4 67 Nitrogen %weight 0.46 0.78 Sulfur %weight 0.6425 1.1496 sediments %weight <0.01 0.12

Comparing with Example 1, a higher level of hydrotreating is observed with a lower density, lower sulfur, nitrogen, metals, asphaltenes and Conradson carbon contents. In addition, RSV contains less sediment and is therefore more stable, in particular thanks to the presence of heavy aromatics from the recycled DAO upstream of the second hydroconversion step.

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

Deasphalting step

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

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in table 36 below are obtained. <b>Table 36</b> CAD Residual asphalt Yield %weight of SDA load 71.9 28.1 Density 0.9897 1,285 Carbon Conradson %weight 5.7 > 30 C ₇ Asphaltenes %weight < 0.05 27 Nickel + Vanadium ppm weight < 4 236 Nitrogen %weight 0.39 1.8 Sulfur %weight 0.7381 2,203

Second split section

After the deasphaltor D , the DAO cut produced is sent to a second fractionation section ( e ) carried out in a fractionation section E composed by a series of flashes, an atmospheric distillation column and a vacuum distillation column following which a light DAO cut (DAO-) boiling at a temperature essentially comprised below 580° C. and a heavy DAO cut (DAO+) boiling mainly at a temperature greater than or equal to 580° C. are recovered. The characteristics of the light DAO and heavy DAO cut are given in table 37 below. <b>Table 37</b> CAD- CAD+ Distillation yield %weight 54.0 46.0 Density 0.9374 1,059 Carbon Conradson %weight 0.28 12.1 C ₇ Asphaltenes %weight < 0.05 not measured Nickel + Vanadium ppm weight <4 <4 Molybdenum ppm weight < 1 not measured Nitrogen %weight 0.31 0.48 Sulfur %weight 0.5605 0.9469

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

Conversion step in an FCC unit

The light DAO cut (DAO-) from the second fractionation section ( e ) carried out in the fractionation section E is then sent to a fluidized bed 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 starting charge. On the other hand, the liquid fraction from the FCC unit still contains an unconverted 540°C+ fraction, the yield of which is only 0.4% by weight relative to the FCC charge, as indicated in Table 38. <b>Table 38</b> Unity FCC Gasoline yield (C5 - 220°C) %weight 47.3 Diesel efficiency (220 - 360°C) %weight 13.1 Yield Distillate Under Vacuum (360 - 540°C) %weight 9.8 Vacuum Residue Yield (540°C+) %weight 0.4

Overall performance

According to the process according to the invention illustrated in this example, comprising recycling of the DAO to the last hydroconversion step, the conversion per pass of the 540° C.+ fraction of the fresh feed from the hydroconversion section is 60.9% by weight. The unconverted vacuum residue fraction contains 0.12% by weight of sediment, 67 ppm by weight of metals and a Conradson Carbon content of 28% by weight. This cut is therefore very difficult to value. Deasphalting of unconverted vacuum residue makes it possible to extract a recoverable fraction by separating the RSV into a DAO fraction (which represents approximately 72% of the RSV) and an asphalt fraction. The DAO fraction contains almost no more 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 in order 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 full at the inlet of the last hydroconversion step. 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 hydrotreating section. Thanks to the conversion of the light DAO in the FCC unit, an additional conversion of 4.1% by weight is obtained, leading to an overall conversion of the scheme according to the invention of 77.5% by weight of the 540° C.+ fraction of the fresh load.

It is therefore noted that, compared to example 1, the conversion is much higher (+13.5 conversion points), while keeping a stable RSV which 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 greater (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 scheme 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 their cleaning. Compared to example 3, the use of an FCC unit for the conversion of the light DAO cut makes it possible to produce more gasoline and less diesel.

Example 7: Process according to the invention, aimed at increasing the overall conversion of the 540° C.+ fraction

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 an ebullated bed followed by a deasphalting stage and a fractionation stage, with recycling of the heavy DAO at the inlet of the last hydroconversion reactor and conversion of the light DAO in an FCC unit. As the content in sediment is reduced in the process according to the invention, this latter reactor will be operated under more severe conditions in order to increase the overall conversion of the process.

First stage of hydroconversion.

The fresh feed from Table 2 is sent in its entirety to a first hydroconversion section A ₁ in the presence of hydrogen to undergo a first hydroconversion stage ( a ₁ ). This section A ₁ is identical to that described in example 1.

The operating conditions applied to this first hydroconversion step ( a ₁ ) are presented in Table 39 below. <b>Table 39</b> Step (a ₁ ) VVH reactor h ^-1 0.60 P total MPa 16 Temperature °C 420 Hydrogen quantity Nm ³ /m ³ 750

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

Intermediate separation stage

The hydroconverted liquid effluent is then sent to an intermediate separation section B ₁ composed of a single gas/liquid separator operating at the pressure and temperature of the reactor 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 below 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 40. <b>Table 40</b> Charge Heavy fraction from B ₁ Density 0.9862 Carbon Conradson %weight 12.2 C ₇ Asphaltenes %weight 4.9 Nickel + Vanadium ppm weight 80 Nitrogen %weight 0.60 Sulfur %weight 1.3922

Second, hydroconversion step

In this example of the process according to the invention, the heavy effluent from the intermediate separation section B ₁ is completely mixed with the heavy DAO from the second fractionation section ( e ) in a heavy effluent/DAO volume ratio of 75/25. The composition of this filler is shown in Table 41. <b>Table 41</b> Stage load (a ₂ ) Density 0.9964 Carbon Conradson %weight 11.6 C ₇ Asphaltenes %weight 3.6 Nickel + Vanadium ppm weight 59 Nitrogen %weight 0.55 Sulfur %weight 1.2671

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

The operating conditions applied in the hydroconversion stage ( a ₂ ) are presented in table 42 below. <b>Table 42</b> Step (a ₂ ) VVH reactor h ^-1 0.72 P total MPa 15.6 Temperature °C 425 Hydrogen quantity Nm ³ /m ³ 250

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

First split section

The hydroconverted liquid effluent 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 vacuum distillation column at the following which a vacuum distillate fraction boiling at a temperature essentially between 350° C. and 500° C. (DSV) and an unconverted vacuum residue fraction boiling at a temperature greater than or equal to 500° C. (RSV) are recovered. Returns relative to fresh feed and product grades are given from this first fractionation section are shown in Table 43 below. <b>Table 43</b> DSV RSV Yield relative to fresh load %weight 30.8 36.8 Density 0.9558 1,061 Carbon Conradson %weight 0.9 29 C ₇ Asphaltenes %weight < 0.05 10.2 Nickel + Vanadium ppm weight <4 65 Nitrogen %weight 0.47 0.82 Sulfur %weight 0.6541 1.2158 sediments %weight <0.01 0.23

Comparing with Example 1, a higher level of hydrotreating is observed with lower density, lower sulfur, nitrogen, metals, asphaltenes and Conradson carbon contents. In addition, RSV contains less sediment and is therefore more stable, in particular thanks to the presence of heavy aromatics from the recycled DAO upstream of the second hydroconversion step.

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

Deasphalting stage

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

At the outlet of the deasphalter, a DAO and a residual asphalt having the characteristics given in table 44 below are obtained. <b>Table 44</b> CAD Residual asphalt Yield %weight of SDA load 71.6 28.4 Density 0.9902 1,294 Carbon Conradson %weight 6.1 > 30 C ₇ Asphaltenes %weight < 0.05 > 30 Nickel + Vanadium ppm weight < 4 226 Nitrogen %weight 0.40 1.8 Sulfur %weight 0.7894 2,291

Second split section

After the deasphaltor D , the DAO cut produced is sent to a second fractionation section ( e ) carried out in a fractionation section E composed by a series of flashes, an atmospheric distillation column and a vacuum distillation column following which a light DAO cut (DAO-) boiling at a temperature essentially comprised below 580° C. and a heavy DAO cut (DAO+) boiling mainly at a temperature greater than or equal to 580° C. are recovered. The characteristics of the light DAO and heavy DAO cut are given in table 45 below. <b>Table 45</b> CAD- CAD+ Distillation yield %weight 38.8 61.2 Density 0.9397 1.025 Carbon Conradson %weight 0.20 9.8 C ₇ Asphaltenes %weight < 0.05 not measured Nickel + Vanadium ppm weight <4 <4 Molybdenum ppm weight < 1 not measured Nitrogen %weight 0.35 0.43 Sulfur %weight 0.5702 0.9283

The heavy DAO cut (DAO+) from fraction stage (e) is sent in full 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) produced in the fractionation section E is then sent to a fluidized bed 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 increases the overall conversion of the starting charge. On the other hand, the liquid fraction from the FCC unit still contains an unconverted 540°C+ fraction, the yield of which is only 0.4% by weight relative to the FCC charge, as indicated in Table 46. <b>Table 46</b> Unity FCC Gasoline yield (C5 - 220°C) %weight 47.2 Diesel efficiency (220 - 360°C) %weight 13.3 Yield Distillate Under Vacuum (360 - 540°C) %weight 9.9 Vacuum Residue Yield (540°C+) %weight 0.4

Overall performance

According to the process according to the invention illustrated in this example, comprising recycling of the DAO to the last hydroconversion step, the conversion per pass of the 540° C.+ fraction of the fresh feed from the hydroconversion section is 64.6% by weight. The unconverted vacuum residue fraction contains 0.23% by weight of sediment, 65 ppm by weight of metals and a Conradson Carbon content of 29% by weight. This cut is therefore very difficult to value. The deasphalting of the unconverted vacuum residue makes it possible to extract a recoverable fraction by separating the RSV into a DAO fraction (which represents approximately 72% of the RSV) and an asphalt fraction. The DAO fraction contains almost no more 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 in order 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 full at the inlet 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 hydrotreating section. Thanks to the conversion of the light DAO in the FCC unit, an additional conversion of 4.0% by weight is obtained, leading to an overall conversion of the scheme according to the invention of 83.2% by weight of the 540°C+ fraction of the fresh load.

It is therefore noted that, compared to 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 wt% instead of 0.20 wt%). Compared to example 2, the conversion is not only greater (more than 12 additional conversion points), but the Residual RSV contains less sediment (0.23% by weight instead of 0.34% by weight) and therefore remains more stable despite the 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 the scheme of example 2 not in accordance with the invention, allowing a longer operation before the stop for their cleaning. Compared to example 3, the use of an FCC unit for the conversion of the light DAO cut makes it possible to produce more gasoline and less diesel.

Claims (15)

1. 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 (a₁ ) of at least a portion of said heavy hydrocarbon feedstock in the presence of hydrogen in an initial hydroconversion section (A₁ ), performed under conditions for obtaining a liquid effluent with a reduced content of sulfur, Conradson carbon, metals and nitrogen;

   - (n-1) additional hydroconversion step(s) (a _i ) in (n-1) additional hydroconversion section(s) (A _i ), in the presence of hydrogen, of at least a portion or all of the liquid effluent obtained from the preceding hydroconversion step (a _i-1 ) or optionally of a heavy fraction obtained from an optional intermediate separation step (b _j ) in an intermediate separation section (B _j ) between two consecutive hydroconversion steps separating a portion or all of the liquid effluent obtained from the preceding hydroconversion step (a _i-1 ) to produce at least one heavy fraction predominantly boiling at a temperature of greater than or equal to 350°C, the (n-1) additional hydroconversion step(s) (a _i ) being performed so as to obtain a hydroconverted liquid effluent with a reduced content of sulfur, Conradson carbon, metals and nitrogen,

   n being the total number of hydroconversion steps, with n greater than or equal to 2, i being an integer ranging from 2 to n and j being an integer ranging from 1 to (n-1), and the initial hydroconversion section (A₁ ) and additional hydroconversion section (A₁ ) each including at least one three-phase reactor operating as an ebullated bed or as a hybrid bed, containing at least one hydroconversion catalyst which is used in the form of extrudates or beads;

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

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

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

   - a step of recycling (f) of at least a portion of the DAO obtained from step (d) and/or of at least a portion of the heavy DAO fraction obtained from step (e) into an additional hydroconversion step (a _i ) and/or into an intermediate separation step (b _j ).
2. Process according to Claim 1, in which said heavy hydrocarbon feedstock has a sulfur content of at least 0.1% by weight, a Conradson carbon content of at least 0.5% by weight, a C₇ asphaltene content of at least 1% by weight and a metal content of at least 20 ppm by weight, and said heavy hydrocarbon feedstock is a crude oil or consists of atmospheric residues and/or of vacuum residues obtained from the atmospheric and/or vacuum distillation of a crude oil, and preferably consists of vacuum residues obtained from the vacuum distillation of a crude oil.
3. Process according to Claim 1 or Claim 2, in which said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating as an ebullated bed, with an ascending stream of liquid and of gas.
4. Process according to any one of Claims 1 to 3, in which said three-phase reactor containing at least one hydroconversion catalyst is a three-phase reactor operating as a hybrid bed, said hybrid bed including at least one catalyst maintained in said three-phase reactor and at least one catalyst entrained out of said three-phase reactor.
5. Process according to any one of the preceding claims, in which the initial hydroconversion step (a₁ ) is performed at an absolute pressure of between 2 and 38 MPa, at a temperature of between 300°C and 550°C, at an hourly space velocity HSV relative to the volume of each three-phase reactor of between 0.05 h^-1 and 10 h^-1 and with an amount of hydrogen mixed with the heavy hydrocarbon feedstock of between 50 and 5000 normal cubic metres (Nm³) per cubic metre (m³) of heavy hydrocarbon feedstock.
6. Process according to any one of the preceding claims, in which the additional hydroconversion step(s) (a _n) are performed at a temperature of between 300°C and 550°C, and greater than the temperature applied in the initial hydroconversion step (a₁ ), with an amount of hydrogen mixed with the heavy hydrocarbon feedstock of between 50 and 5000 normal cubic metres (Nm³) per cubic metre (m³) of heavy hydrocarbon feedstock, and less than the amount of hydrogen applied in the initial hydroconversion step (a₁ ), with an absolute pressure of between 2 and 38 MPa, and at an hourly space velocity HSV relative to the volume of each three-phase reactor of between 0.05 h^-1 and 10 h^-1.
7. Process according to any one of the preceding claims, in which the deasphalting step (d) is performed in an extraction column at a temperature of between 60°C and 250°C with at least one hydrocarbon-based solvent containing from 3 to 7 carbon atoms, and a solvent/feedstock ratio (volume/volume) of between 3/1 and 16/1 and preferably between 4/1 and 8/1.
8. Process according to any one of the preceding claims, in which at least a portion of the heavy hydrocarbon feedstock is sent into at least one additional hydroconversion section (A _i ) and/or into at least one intermediate separation section (B _j ) and/or into the first fractionation section (C) and/or into the deasphalter (D).
9. Process according to any one of the preceding claims, in which a hydrocarbon feedstock external to the process is sent into the initial hydroconversion section (A₁ ) and/or into at least one additional hydroconversion section (A₁ ) and/or into at least one intermediate separation section (B _j ) and/or into the first fractionation section (C) and/or into the deasphalter (D).
10. Process according to any one of the preceding claims, also comprising at least one recycling step as follows:

    - recycling (r ₁) of a portion or all of the light DAO fraction obtained from step (e) into the initial hydroconversion section (A₁ ) and/or into at least one additional hydroconversion section (A _i ) and/or into at least one intermediate separation section (B _j ) and/or into the first fractionation section (C);

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

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

    - recycling (r₄ ) of a portion or all of the residual asphalt obtained from step (d) into the initial hydroconversion section (A₁ ) and/or into at least one additional hydroconversion section (A _i );

    - recycling (r₅ ) of a portion of the hydroconverted liquid effluent from a given additional hydroconversion section (A₁ ):

    - into the initial hydroconversion section (A₁ ), and/or

    - into another additional hydroconversion section (A₁ ) positioned upstream of said given section (A _i ), and/or

    - into an intermediate separation section (B _j ) positioned upstream of said given section (A _i );

    - recycling (r₆ ) of a portion of the heavy fraction and/or of a portion or all of one or more intermediate fractions obtained from a given intermediate section (B _j ):

    - into the initial hydroconversion section (A₁ ), and/or

    - into an additional hydroconversion section (A _i ) positioned upstream of said given intermediate section (B _j ), and/or

    - into another intermediate separation section (B _j ) positioned upstream of said given section (B _j );

    - recycling (r₇ ) of a portion of the heavy fraction and/or of a portion or all of one or more intermediate fractions obtained from the first fractionation section (C):

    - into the initial hydroconversion section (A₁ ), and/or

    - into an additional hydroconversion section (A _i ), and/or

    - into an intermediate separation section (Bj ).
11. Conversion process according to any one of the preceding claims, in which n is equal to 2, and comprising the following successive steps:

    - an initial step of hydroconversion (a₁ ) of at least a portion of said heavy hydrocarbon feedstock in the presence of hydrogen in an initial hydroconversion section (A₁ ), performed under conditions for obtaining a liquid effluent with a reduced content of sulfur, Conradson carbon, metals and nitrogen;

    - an additional step of hydroconversion (a₂ ) in an additional hydroconversion section (A₂ ), in the presence of hydrogen, of at least a portion or all of the liquid effluent obtained from the initial hydroconversion step (a₁ ) or optionally of a heavy fraction obtained from an optional step of intermediate separation (b₁ ) in an intermediate separation section (B₁ ) between the initial hydroconversion step (a₁ ) and the additional hydroconversion step (a₂ ) separating a portion or all of the liquid effluent obtained from the initial hydroconversion step (a₁ ) into at least one light fraction predominantly boiling at a temperature of less than 350°C and at least one heavy fraction predominantly boiling at a temperature of greater than or equal to 350°C, the additional hydroconversion step (a₂ ) being performed so as to obtain a hydroconverted liquid effluent with a reduced content of sulfur, Conradson carbon, metals and nitrogen,

    the initial hydroconversion section (A₁ ) and additional hydroconversion section (A ₂) each including at least one three-phase reactor operating as an ebullated bed or as a hybrid bed, containing at least one hydroconversion catalyst used in the form of extrudates or of beads;

    - a first step of fractionation (c) in a first fractionation section (C) of a portion or all of the hydroconverted liquid effluent obtained from the additional hydroconversion step (a₂ ) producing at least one heavy cut predominantly boiling at a temperature of greater than or equal to 350°C, said heavy cut containing a residual fraction boiling at a temperature of greater than or equal to 540°C;

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

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

    - a step of recycling (f) of at least a portion of the DAO obtained from step (d) and/or of at least a portion of the heavy DAO fraction obtained from step (e) into an additional hydroconversion step (a₂ ) and/or into an intermediate separation step (b₁ ).
12. Process according to any one of the preceding claims, including the recycling (f) of all of the DAO obtained from step (d) or of all of the heavy fraction obtained from the second fractionation step (e) into the last additional hydroconversion step (a _i ), and preferably into the additional hydroconversion step (a₂ ) when n is equal to 2 and when in addition all of the liquid effluent obtained from step (a₁) is sent into step (b₁ ), all of the heavy fraction obtained from step (b₁ ) is sent into step (a₂ ), all of the hydroconverted liquid effluent obtained from step (a₂ ) is sent into step (c), and all of the heavy cut obtained from step (c) is sent into step (d).
13. Process according to any one of Claims 1 to 11, including the recycling (f) of all of the DAO obtained from step (d) or of all of the heavy fraction obtained from the second fractionation step (e) into an intermediate separation step (b _j ), and preferably into the intermediate separation step (b ₁) between the initial hydroconversion step (a₁ ) and the additional hydroconversion step (a₂ ) when n is equal to 2 and when in addition all of the liquid effluent obtained from step (a₁ ) is sent into step (b₁ ), all of the heavy fraction obtained from step (b₁ ) is sent into step (a₂ ), all of the hydroconverted liquid effluent obtained from step (a₂ ) is sent into step (c), and all of the heavy cut obtained from step (c) is sent into step (d).
14. Process according to any one of Claims 1 to 11, not including an intermediate separation step (b _j ) and including the recycling (f) of all of the DAO obtained from step (d) into the last additional hydroconversion step (a _i ), and preferably into the additional hydroconversion step (a₂ ) when n is equal to 2 and when in addition all of the liquid effluent obtained from step (a₁ ) is sent into step (a₂ ), all of the hydroconverted liquid effluent obtained from step (a₂ ) is sent into step (c), and all of the heavy cut obtained from step (c) is sent into step (d).
15. Process according to any one of Claims 1 to 14, in which said hydroconversion catalyst of said at least one three-phase reactor of the initial hydroconversion section (A₁ ) and of the additional hydroconversion section(s) (A₁ ) contains at least one non-noble group VIII metal chosen from nickel and cobalt and at least one group VIB metal chosen from molybdenum and tungsten, and preferably including an amorphous support.

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