FR3113062A1 - Residue hydroconversion process with several hydroconversion stages incorporating a deasphalting step - Google Patents

Abstract

The present invention relates to a method for converting a heavy hydrocarbon feedstock (10) comprising: a) the hydroconversion of said feedstock (10) in a first hydroconversion stage (A1) to form a first effluent (12); b) hydroconverting a DAO (15) in a second hydroconversion stage (A2) to form a second effluent (18); c) sending the first and second effluents to a separation system (C); d) fractionating said mixed first and second effluents in said separation system (C) to form at least one distillate hydrocarbon fraction (13) and one residue hydrocarbon fraction (14); e) sending at least part of the fraction (14) to a solvent deasphalting unit (D) to obtain the DAO (15) and an asphalt fraction (16), in which the hourly volume velocity for step a) is between 0.05 and 0.09 h-1. Figure 1 to be published

Description

Residue hydroconversion process with several hydroconversion stages incorporating a deasphalting step

The present invention relates to the conversion of petroleum feedstocks, in particular heavy hydrocarbon feedstocks containing a fraction of at least 50% by weight, preferably at least 80% by weight, having a boiling point of at least 300°C.

These feeds can be a crude oil or be derived from the distillation and/or refining of a crude oil, typically residues from the atmospheric and/or vacuum distillation of a crude oil.

In particular, the present invention relates to a process for hydroconversion and deasphalting of residues comprising several stages of hydroconversion.

Hydrocarbon compounds are useful for several purposes. In particular, the hydrocarbon compounds are useful, among other things, as fuels, solvents, degreasers, cleaning agents and polymer precursors. The most important source of hydrocarbon compounds is currently crude oil. Refining crude oil into separate fractions of hydrocarbon compounds is a well-known processing technique.

Crude oils vary widely in their composition, and their physical and chemical properties. Heavy crude oils are characterized by relatively high viscosity, low API gravity and a high percentage of high boiling point components (e.g. having a normal boiling point of at least 540°C).

Refined petroleum products generally have a higher average hydrogen to carbon ratio than the petroleum cuts from which they are derived, on a molecular basis. Therefore, the upgrading of a hydrocarbon fraction from an oil refinery is generally classified into one of two categories: hydrogen addition and carbon release. The addition of hydrogen is carried out by processes such as hydrotreating (for example the desulfurization of atmospheric residues or "ARDS" for "Atmospheric Residue DeSulfuration" in English) and hydroconversion (commonly called "residue hydrocracking" in English ). Carbon rejection processes typically produce a stream of high carbon rejected material which may be a liquid or a solid; for example, coke deposits. Carbon rejection is carried out by processes such as fluidized bed catalytic cracking, known as “FCC” for “Fluid Catalytic Cracking”, and delayed coking (commonly known as “Delayed Coking”).

Hydroconversion processes can be used to upgrade higher boiling point compounds, such as resids, typically found in heavy crude oil, by converting them to lower boiling point compounds. Thus, at least part of a residue sent to a hydroconversion reactor is converted into a product with a lower boiling point. The conversion of the residue corresponds to the fraction of the residue which has been converted. The unreacted residue (commonly called "UCO" for "UnConverted Oil" in English) can be recovered and either taken out of the hydroconversion process, or recycled in the hydroconversion reactor in order to increase the overall conversion of the residue.

The conversion of residues in a hydroconversion reactor can depend on a variety of factors, including the composition of the feed (ie the residue); the type of reactor used; the severity of the reaction, which includes the operating conditions of temperature and pressure; the hourly volumetric velocity of the reactor or "VVH" (commonly called "LHSV" for "Liquid Hourly Space Velocity" in English); and catalyst type and performance. The hourly volume velocity (VVH) with respect to the reactor is defined as the ratio of the volume flow rate of liquid feed entering the reactor, measured at ambient conditions, also called standard conditions (typically at 15°C and 1 atm, i.e. 0, 101325 MPa), relative to the volume of the reactor. The hourly volume velocity with respect to the catalyst is defined as the ratio of the volume flow rate of liquid charge which enters the reactor, measured at ambient conditions (typically at 15°C and 1 atm, i.e. 0.101325 MPa), relative to the volume catalyst in the reactor. The hourly volume velocity therefore has the unit h ⁻¹ and is inversely proportional to the residence time in the reactor or in the catalytic bed.

The severity of the reaction can be used to increase the conversion, i.e. more severe operating conditions make it possible to increase the conversion of the charge. However, as the severity of the reaction increases, side reactions can occur inside the hydroconversion reactor to produce various by-products in the form of coke precursors, sediments, other deposits as well as by-products that form a secondary liquid phase (commonly called “mesophase”). Excessive formation of coke precursors deactivates the hydroconversion catalyst by poisoning and can interfere with its further processing. Deactivation of the hydroconversion catalyst can not only significantly reduce residue conversion, but can also require more frequent costly catalyst replacements. The formation of a secondary liquid phase not only deactivates the hydroconversion catalyst, thus leading to higher catalyst consumption, but can also defluidize the catalyst thus also limiting the maximum conversion. This defluidization leads to the formation of "hot spots" within the catalyst bed, exacerbating coke formation, which further deactivates the hydroconversion catalyst. Excessive sediment formation deactivates the hydroconversion catalyst by poisoning and fouls equipment downstream of the reactor, such as separators and distillation columns.

The formation of sediments within the hydroconversion reactor also depends on the quality of the feed which feeds the reactor. For example, the asphaltenes which may be present in the feed sent to the hydroconversion reactor are particularly prone to form sediments when they are subjected to severe operating conditions. Thus, it may be desirable to separate the asphaltenes from the residue in order to increase the conversion.

In order to remove the asphaltenes from a heavy hydrocarbon charge of the residue type, it is known to implement solvent deasphalting processes, also called “SDA” for “Solvent DeAsphalting” in English. Solvent deasphalting generally involves the physical separation of more apolar hydrocarbons and more polar hydrocarbons, including asphaltenes, based on their relative solvent affinities. A light solvent such as a C ₃ to C ₇ hydrocarbon can be used to dissolve or suspend the lighter hydrocarbons, forming what is commonly called a DeAsphalted Oil or "DAO" for "DeAsphalted Oil" in English, and allowing the asphaltenes to be rushed. The two phases are then separated and the solvent is recovered. Additional information on solvent deasphalting conditions, solvents and the steps operated can be obtained from US patents 4,239,616, US 4,440,633, US 4,354,922, US 4,354,928 and US 4,536,283, and in chapter 15 "Deasphalting with Paraffinic Solvents" of the book "Heavy Crude Oils: From Geology to Upgrading, An Overview", published by Éditions Technip in 2011.

Processes integrating a solvent deasphalting process and a hydroconversion process in order to remove the asphaltenes from the residues are also known. For example, an example of such an integrated process is described in US Patents 7,214,308, US 7,279,090, and US 7,691,256. separating the asphaltenes from the deasphalted oil. The DAO and the asphaltenes are then each sent to separate hydroconversion reactor systems.

Moderate overall conversions of these residues, on the order of 65% to 70% as described in US Patent 7,214,308, can be obtained with such processes, since the DAO and the asphaltenes are converted separately. However, the hydroconversion of asphaltenes as described is carried out under severe operating conditions, at high conversion, and can present particular problems, as discussed above. For example, the hydroconversion reactor in which the asphaltenes are sent operates under severe conditions in order to increase the conversion, which can also lead to a high rate of sediment formation and a high rate of catalyst replacement. On the contrary, operation of the asphaltene hydroconversion reactor under less severe conditions will suppress the formation of sediments, but the conversion per pass of the asphaltenes will be low. In order to obtain a higher overall conversion of the feed, i.e. of the residue, these processes generally require a high recycling rate of the unreacted residue to one or more of the hydroconversion reactors. Such high volume recycle can significantly increase the size of the upstream hydroconversion reactor and/or solvent deasphalting system.

A process for the hydroconversion of residues is known which addresses the problems set out above, and which aims to provide a high overall conversion of the residue, while reducing the overall size of the equipment of the hydroconversion reactor or of the overall conversion level deasphalting and minimizing catalyst replacement frequency. Thus, patents US Pat. No. 8,287,720, US Pat. No. 9,441,174 and US Pat. the following steps: the hydroconversion of a residue in a first reaction stage in order to form a first hydroconverted effluent, the hydroconversion of a DAO fraction in a second reaction stage in order to form a second effluent, the fractionation of the first hydroconverted effluent and the second hydroconverted effluent to form at least a distillate fraction and a residue fraction, and sending the residue fraction to a deasphalting unit using a solvent to obtain the DAO fraction and a asphalt fraction.

However, the mixture of the first and second hydroconverted effluents, sent to the fractionation stage, is liable to create chemical instability and to cause significant formation of sediments, a source of various problems such as fouling, deactivation of catalysts in treatments in downstream of fractionation etc., as already described above.

Indeed, it has been demonstrated that the mixing of certain hydrocarbon cuts in processes for the hydroconversion of heavy hydrocarbon feedstocks, for example certain fractions of distillate and residues resulting from the fractionation of hydroconverted effluents, could cause chemical instability and lead to significant formation of additional sediment. Surprisingly, it was also demonstrated that a judicious choice of the operating conditions of the different stages made it possible to avoid this generation of new sediments.

Consequently, the present invention aims to provide an improved multi-stage hydroconversion process for heavy residue-type hydrocarbon feedstocks, as described in US patents 8,287,720, US 9,441,174 and US 9,873,839, making it possible to achieve a high overall conversion level while minimizing sediment formation and the risk of equipment fouling.

Objects and Summary of the Invention

Thus, to achieve at least one of the aforementioned objectives, among others, the present invention proposes, according to a first aspect, a process for converting a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling temperature of at least 300°C, comprising the following steps:
a) the hydroconversion of said heavy hydrocarbon feedstock in a first hydroconversion stage to form a first effluent;
b) hydroconversion of a deasphalted oil fraction in a second hydroconversion stage to form a second effluent;
c) sending said first and second effluents to a separation system;
d) fractionating said mixed first and second effluents in said separation system (C) to form at least one distillate hydrocarbon fraction and one residue hydrocarbon fraction;
e) sending at least part of the residue hydrocarbon fraction to a solvent deasphalting unit to obtain the deasphalted oil fraction and an asphalt fraction,
wherein the hourly volume velocity for step a) is between 0.05 h ^-1 and 0.09 h ^-1 .

According to one or more embodiments, the hourly volume velocity implemented in step a) is between 0.05 h ^-1 and 0.08 h ^-1 .

According to one or more embodiments, at least one of the operating temperature and the operating pressure in the second stage of hydroconversion in step b) is higher than the operating temperature and the operating pressure in the first stage of hydroconversion in step a).

Alternatively, at least one of the operating temperature and the operating pressure in the second hydroconversion stage in step b) is lower than the operating temperature and the operating pressure in the first hydroconversion stage in step a ).

According to one or more embodiments, the hourly volume velocity implemented in step b) is between 0.1 h ^-1 and 5.0 h ^-1 .

According to one or more embodiments, at least part of the asphaltenes contained in said heavy hydrocarbon feedstock is converted in the first hydroconversion stage in step a).

According to one or more embodiments, the first hydroconversion stage in step a) is operated at a temperature and a pressure so as to convert said heavy hydrocarbon charge at a conversion rate of between approximately 30% by weight and approximately 95 % weight of said heavy hydrocarbon charge.

According to one or more embodiments, the overall conversion of said heavy hydrocarbon feedstock at the end of the process is at least 60% by weight of said heavy hydrocarbon feedstock, preferably at least 90% by weight of said heavy hydrocarbon feedstock .

According to one or more embodiments, the residue hydrocarbon fraction from step d) comprises hydrocarbon compounds having a boiling point of at least 300° C.

According to one or more embodiments, the first hydroconversion stage comprises a single bubbling bed reactor.

According to one or more embodiments, the second hydroconversion stage comprises at least one bubbling bed reactor and/or one fixed bed reactor.

step d) of fractionation comprises:
- the separation of the first and second effluents in a high pressure and high temperature separator in order to obtain a gas phase product and a liquid phase product;
- separation of the product in the liquid phase in an atmospheric distillation column in order to recover a first light fraction comprising hydrocarbon compounds boiling in a range of atmospheric distillates and a first heavy fraction comprising hydrocarbon compounds having a boiling point of at minus 300°C;
- separation of the heavy fraction in a vacuum distillation column in order to recover a second light fraction comprising hydrocarbon compounds boiling in a range of vacuum distillates and a second heavy fraction comprising hydrocarbon compounds having a boiling point of at least 450°C; And
- sending the second heavy fraction to the solvent deasphalting unit in step e) as residue hydrocarbon fraction,
in which the hydroconversion step a) of the heavy hydrocarbon feedstock comprises:
- Sending hydrogen and the heavy hydrocarbon charge to a first hydroconversion reactor containing a first hydrocracking catalyst;
- bringing the heavy hydrocarbon feedstock into contact with hydrogen in the presence of the first hydrocracking catalyst under temperature and pressure conditions making it possible to carry out the conversion of at least a portion of said heavy hydrocarbon feedstock;
- recovering the first effluent from the first hydroconversion reactor;
and wherein the hydroconversion step b) of the deasphalted oil fraction comprises:
- sending hydrogen and the deasphalted oil fraction to a second hydroconversion reactor containing a second hydrocracking catalyst;
- bringing the fraction of deasphalted oil and hydrogen into contact in the presence of the second hydrocracking catalyst under temperature and pressure conditions making it possible to carry out the conversion of at least a portion of the deasphalted oil; And
- the recovery of the second effluent from the second hydroconversion reactor.

According to one or more embodiments, the method further comprises cooling the product in the gas phase in order to recover a gas fraction containing hydrogen and a distillate fraction; and passing the distillate fraction to the atmospheric distillation column.

According to one or more embodiments, the method further comprises recycling at least a portion of the gas fraction containing hydrogen in at least one of the first hydroconversion reactor and the second hydroconversion reactor.

According to one or more embodiments, the method further comprises cooling the second heavy fraction via direct heat exchange with at least one of a portion of the residue and a portion of the first heavy fraction.

According to one or more embodiments, the residue hydrocarbon fraction comprises hydrocarbon compounds having a boiling point of at least 450°C.

According to one or more embodiments, the hydroconversion step a) is carried out under an absolute pressure of between 2 MPa and 35 MPa, at a temperature of between 300° C. and 550° C., and under a quantity of hydrogen mixed with the heavy hydrocarbon charge of between 50 and 5000 Nm ³ /m ³ of heavy hydrocarbon charge.

According to one or more embodiments, the first effluent and second effluent mixed in the separation system in the fractionation step d) do not create sediments.

According to one or more embodiments, the heavy hydrocarbon feedstock contains a fraction of at least 80% having a boiling point of at least 300° C., and is preferably a crude oil or consists of atmospheric residues and/or or vacuum residues from the atmospheric and/or vacuum distillation of a crude oil, and preferably consists of vacuum residues from the vacuum distillation of a crude oil.

According to one or more embodiments, the heavy hydrocarbon charge 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% by weight, and a metal content of at least 20 ppm by weight.

Other objects and advantages of the invention will appear on reading the following description of examples of particular embodiments of the invention, given by way of non-limiting examples, the description being made with reference to the appended figures described below. -After.

List of Figures

There is a simplified diagram of a hydroconversion and multi-stage deasphalting process according to the invention.

There is a simplified diagram of an example of a multi-stage hydroconversion and deasphalting process according to the invention.

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

The present invention generally relates to a method for converting a petroleum feedstock, in particular a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling point of at least 300°C. In particular, the present invention relates to a process for the hydroconversion and deasphalting of such a feed, comprising several hydroconversion steps.

In accordance with the invention, the process for converting the heavy hydrocarbon feedstock comprises the following steps, which are detailed below:

a) hydroconversion of the heavy hydrocarbon feedstock in a first hydroconversion stage (A ₁ ) to form a first hydroconverted effluent;

b) the hydroconversion of a deasphalted oil fraction in a second hydroconversion stage (A ₂ ) in order to form a second effluent;

c) sending the first and second hydroconverted effluents to a separation system (C);

d) fractionating the mixed first and second hydroconverted effluents in the separation system (C) to form at least one hydrocarbon distillate fraction and one hydrocarbon residue fraction;

e) sending at least part of the residue hydrocarbon fraction to a solvent deasphalting unit (D) to obtain the deasphalted oil fraction and an asphalt fraction,

wherein the hourly volume rate relative to the volume of the reactor for step a) is between 0.05 h ^-1 and 0.09 h ^-1 .

Throughout the description, the fractions of the various hydrocarbon compounds or hydrocarbon cuts are expressed by weight unless otherwise specified.

The ranges of temperature, pressure, are understood as limits included, unless otherwise specified.

The pressures are expressed in absolute values, unless indicated otherwise. The description of the process according to the invention below refers to the general diagram of the process according to the invention of the .

Load

The heavy hydrocarbon feedstock 10 treated in the process according to the invention is a heavy hydrocarbon feedstock containing a fraction of at least 50% by weight, preferably at least 80% by weight, having a boiling point of at least 300 °C, preferably at least 350°C, and even more preferably at least 375°C.

The charge is predominantly liquid under the pressure and temperature conditions of the reactor into which the charge is sent.

The heavy loads treated can be a crude oil or be derived from the refining of a crude oil, typically residues from the atmospheric and/or vacuum distillation of a crude oil.

Preferably, the heavy hydrocarbon feedstock treated in the process according to the invention is a residual hydrocarbon feedstock, also called more simply residue, which can include various fractions of heavy crude oil and cuts resulting from the refining of crude oil. The residue contains a fraction of at least 50% by weight, preferably at least 80% by weight having a boiling point of at least 300°C.

For example, the feedstock treated may be an atmospheric distillation residue from the primary fractionation (known as “SR” for “Straight Run”) of a crude oil, a vacuum distillation residue from the primary fractionation of a crude oil, an atmospheric or vacuum distillation residue of a hydrotreated, hydrocracked or hydroconverted effluent, a vacuum distillate (known as "VGO" for "Vacuum Gas Oil" in English) resulting from the primary fractionation of crude oil, a vacuum distillate (VGO ) a hydrotreated, hydrocracked or hydroconverted effluent, a distillate (known as “Cycle Oil” in English) or a residue (known as “Slurry Oil” in English) from the fractionation column of an effluent from an FCC unit, a vacuum distillate from a delayed coking unit (called "HCGO" for "Heavy Coker Gas Oil" in English), a vacuum distillate from a visbreaking unit, a deasphalted oil from a deasphalting unit, a asphalt from a deasphalt unit ge, as well as other similar hydrocarbon effluents, or a combination thereof, each of said effluents being able to come from a primary fractionation and/or be derived from a process, or and/be hydroconverted, and/or be hydrotreated, or partially desulfurized and/or demetallized.

The cited fillers generally contain various impurities, including asphaltenes, metals, sulfur, nitrogen, Conradson carbon (“CCR” for “Carbon Conradson Residue” in English). The heavy hydrocarbon feedstock treated generally 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% by weight , and a metal content of at least 20 ppm by weight.

In the present description, the asphaltenes are in particular the asphaltenes C ₇ , which are compounds insoluble in heptane, according to standard NFT 60-115 or standard ASTM D 6560 (standards describing the method for determining said asphaltenes C ₇ ) .

P remy e r eta g e of hydroconversion : hydroconversion heavy liquid load - step a)

The process according to the invention for converting the heavy hydrocarbon feed into lighter hydrocarbon compounds initially comprises a step a) of hydroconversion of said feed, including all the asphaltenes contained therein.

The heavy hydrocarbon feed 10 is sent to a first hydroconversion stage A ₁ to undergo hydroconversion there, and form a reaction product here called first hydroconverted effluent 12.

All of the heavy hydrocarbon feedstock 10, including the asphaltenes, can thus be reacted with hydrogen 11 over a hydroconversion catalyst in the first hydroconversion stage A ₁ to convert at least some of the hydrocarbon compounds into lighter molecules, including the conversion of at least some of the asphaltenes.

However, as the severity of the reaction increases, the conversion of the heavy load increases, but it is accompanied by the formation of sediment. These products are insoluble in their environment and can therefore precipitate in lines, equipment (separators, distillation columns, exchangers, filters, etc.) and storage tanks. The sediment content is measured according to the IP 375 standard or the ASTM D 4870 standard (standards describing the method for determining said sediments).

In order to mitigate the formation of sediment, the first stage of hydroconversion can be carried out at temperatures and pressures allowing to avoid high rates of sediment formation and fouling of the catalyst, i.e. operating conditions of moderate severity and leading to lower heavy load conversion.

This first hydroconversion stage is advantageously operated at a temperature between 300° C. and 550° C., preferably between 350° C. and 500° C. and in a preferred manner between 370° C. and 440° C., and more preferably between 380°C and 440°C. The absolute operating pressure can be between 2 MPa and 35 MPa, preferably between 5 MPa and 25 MPa and more preferably between 6 MPa and 20 MPa. The quantity 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 taken under standard temperature and pressure conditions (typically 15° C. and 1 atm, ie 0.101325 MPa), preferably between 100 Nm ³ /m ³ and 2000 Nm ³ /m ³ and very preferably between 200 Nm ³ /m ³ and 1000 Nm ³ /m ³ .

According to the invention, the hourly volume velocity (VVH) for this first hydroconversion stage is between 0.05 h ^-1 and 0.09 h ^-1 , the hourly volume velocity being the liquid feed rate of the stage a) hydroconversion taken under standard temperature and pressure conditions (typically 15° C. and 1 atm, ie 0.101325 MPa), relative to the total volume of the reactor(s) used in step a). The hourly volume velocity can be between 0.05 h ^-1 and 0.08 h ^-1 .

These temperature conditions associated with a high residence time (low VVH) make it possible to simultaneously improve the overall level of conversion of the process (i.e. the level of conversion of the initial charge 10 reached at the end of the process including the two stages hydroconversion) and the stability of the mixture with the second hydroconverted effluent 18 from the second hydroconversion stage b), sent to the common fractionation stage d), in particular by better compatibility of the first hydroconverted effluent 12 with the second effluent hydroconverted 18. Surprisingly, it was demonstrated that a high residence time (low VVH) combined with a lower temperature made it possible to avoid this generation of new sediments when mixing the two hydroconverted effluents 12 and 18 .

In particular, the two hydroconverted effluents mixed in the separation system (C) in the fractionation step d) do not create sediments. The mixture of hydroconverted effluents (12, 18) for example has a lower sediment content than that of said first hydroconverted effluent 12.

Indeed, without being linked to a particular theory, it has been demonstrated by the inventors that when a high conversion in the first hydroconversion stage is obtained by long residence times (specific range for the VVH), the effluent contains a low sediment content, but also a low asphaltene content. Thus, the mixing of the first and second effluents does not surprisingly create additional sediments and can even lead to lower sediment contents than expected. The very high conversion of the asphaltenes in the first stage of hydroconversion makes it possible to avoid the incompatibility between the two effluents identified in the processes of the prior art, thanks to the high residence times used according to the present invention. The problem with the mixing of hydroconversion effluents appears to arise when first stage hydroconversion conversion is moderate, resulting in an effluent that not only contains a relatively high sediment content, but also asphaltenes which are incompatible with highly hydrogenated effluents. As a result, the mixing of the first and second effluents sees a strong increase in the sediment content of the total liquid, which leads to a very strong fouling of the equipment (separators, distillation columns, exchangers, etc.) of the section of separation and which may therefore require regular stops for cleaning.

The conversion of the heavy hydrocarbon feedstock 10 in this first hydroconversion stage can be within a range from approximately 30% by weight to approximately 95% by weight. Said conversion may in particular be between about 30% and 75% by weight, or even between about 45% and about 55% by weight. It may be less than 45% by weight according to certain embodiments.

In addition to hydroconversion of residue 10, sulfur and metal removal can be between about 40% and about 75%, and Conradson carbon removal can be between about 30% and about 60%. These elimination rates are expressed relative to the flow rates of sulphur, metals and Conradson carbon respectively, entering the first stage of hydroconversion A ₁ . These flow rates are obtained from the feed rate and the sulfur, metals and Conradson carbon content initially present in the feed.

A hydroconversion catalyst suitable for this first stage hydroconversion, which can also be a catalyst for hydrotreating reactions, preferably comprises one or more elements from groups 4 to 12 of the periodic table of elements.

The hydroconversion catalyst for this first hydroconversion step a) may comprise, or consist of, or be essentially constituted by, one or more elements chosen from the list consisting of nickel, cobalt, tungsten, molybdenum, supported (s) on a porous substrate such as silica, alumina, titania or combinations thereof.

The nickel or cobalt content, 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 content of molybdenum or tungsten, in particular of 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.

The hydroconversion catalyst for this first hydroconversion stage is advantageously 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 mm and 4.0 mm and a length between 1 mm 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 hydroconversion catalyst used, in the form of extrudates, beads or other shapes, can therefore have an equivalent diameter of between 0.4 mm and 4.4 mm.

These catalysts are well known to those skilled in the art. Whether supplied by a manufacturer or resulting from a process of regeneration of spent catalysts, they are preferably in the form of metal oxides. If necessary, the catalyst in the form of metal oxide(s) can be converted into metal sulphides before or during its use.

The hydroconversion catalyst can be presulfided and/or preconditioned before introduction into the hydroconversion reactor.

The first hydroconversion stage A ₁ can comprise one or more reactors which can be arranged in series and/or in parallel. A suitable reactor for this first hydroconversion stage can be any type of hydroconversion reactor which is a three-phase reactor, ie operating with the three liquid, solid and gaseous phases. A liquid and gas rising current reactor of the fluidized bed or bubbling bed type, ie which is a particular fluidized bed where the catalyst is kept boiling in the reactor, is preferred because of the treatment of the asphaltenes of the heavy hydrocarbon feedstock during of this first hydroconversion step. The ebullated bed processes are described for example in the patents US 4,521,295, US 4,495,060, US 4,457,831 and US 4,354,852, and in chapter 3.5 "Hydroprocessing and Hydroconversion of Residue Fractions" of the work " Catalysis by Transition Metal Sulphides", published by Éditions Technip in 2013.

According to one or more embodiments, the first hydroconversion step a) only comprises a single bubbling bed reactor.

E sending of the effluent from step a) in a common separation system C and fractionation – steps c) and d)

The reaction product from the first hydroconversion step a), i.e. the first hydroconverted effluent 12, is sent to a separation system C, with the reaction product 18 from the hydroconversion of the DAO fraction 15, constituting a second hydroconversion step b) as described below. The separation system C is therefore a common separation system. The first hydroconverted effluent 12 and the second hydroconverted effluent 18, as a mixture, are fractionated to recover at least one distillate hydrocarbon fraction 13 and one residue hydrocarbon fraction 14.

The hydrocarbon fraction of residue 14 comprises a part of the residue 10 sent to the first hydroconversion stage which has not reacted, unconverted asphaltenes, and any hydrocarbon cut boiling in the same range as a residue and resulting from the hydroconversion of the asphaltenes contained in the residue 10 sent to step a).

The hydrocarbon fraction(s) of distillate 13 recovered may (or may) include, among others, gaseous fractions and atmospheric distillates, such as hydrocarbon compounds having a lower boiling temperature. to about 350°C, and vacuum distillates, such as hydrocarbon compounds having a boiling temperature of about 300°C to about 580°C.

The fractionation of the first and second hydroconverted effluents (12, 18) is carried out in the common separation system C placed between the first hydroconversion stage A ₁ and the second hydroconversion stage A ₂ .

The first hydroconverted effluent 12 and the second hydroconverted effluent 18 can be mixed prior to their introduction into the separation system C, as illustrated in .

Alternatively, said effluents (12, 18) can be introduced separately into the separation system C.

Solvent deasphalting – step e)

At least part of the residue hydrocarbon fraction 14 resulting from fractionation step d) is sent to a solvent deasphalting unit D to recover a fraction of DAO (deasphalted oil) 15 and an asphalt fraction 16. The DAO fraction 15 is substantially free of asphaltenes, and asphalt fraction 16 concentrates most of the residue impurities, including asphaltenes.

The solvent deasphalting unit D may be, for example, as described in one or more of US patents US 4,239,616, US 4,440,633, US 4,354,922, US 4,354,928, US 4,536,283, US 4,715,946 and US 7,214,308, and in chapter 15 "Deasphalting with Paraffinic Solvents" of the book "Heavy Crude Oils: From Geology to Upgrading, An Overview", published by Éditions Technip in 2011. Deasphalting is generally carried out at an average temperature of between 60°C and 250°C with at least one light hydrocarbon solvent having from 3 to 7 carbon atoms (C ₃ to C ₇ ), and may include propane, butane, isobutane, pentane, isopentane, hexane, isohexanes, heptane, isoheptanes and mixtures thereof, optionally containing at least one additive. The solvents which can be used and the additives are widely described in the literature. This deasphalting can be carried out in one or more mixer-settlers or in one or more extraction columns.

The solvent/feed (volume/volume) ratios during deasphalting are generally between 4/1 and 9/1, often between 4/1 and 8/1.

The deasphalting unit D produces the DAO practically free of asphaltenes and a residual asphalt concentrating the major part of the impurities of the residue, which is withdrawn.

The DAO yield is generally between 40% and 90% by weight depending on the quality of the heavy liquid fraction sent, the operating conditions and the solvent used. The DAO obtained advantageously has an asphaltene content of less than 1%, preferably less than 0.5%, preferably less than 0.05% by weight, measured as C ₇ insolubles, and even more preferably less than 0, 3% by weight measured in C ₅ insolubles (measured by the ASTM D 893 standard describing the method for determining said C ₅ asphaltenes) and less than 0.05% by weight measured in C ₇ insolubles.

In solvent deasphalting unit D, a light hydrocarbon solvent can be used to selectively dissolve the desired components of the residue hydrocarbon fraction and remove the asphaltenes. According to one or more embodiments, the light hydrocarbon solvent can be a hydrocarbon solvent having from 3 to 7 carbon atoms (C ₃ to C ₇ ), and can comprise propane, butane, isobutane, pentane, isopentane, hexane, isohexanes, heptane, isoheptanes and mixtures thereof.

Second stage g e of hydroconversion : hydroconversion of the DAO – step b)

The DAO fraction 15 from step e) is sent to a second hydroconversion stage A ₂ to undergo hydroconversion and form a reaction product here called second hydroconverted effluent 18. The DAO fraction 15 can thus be reacted with hydrogen 17 on a hydroconversion catalyst in the second hydroconversion stage A ₂ , to convert at least some of the hydrocarbon compounds present in the DAO into lighter molecules.

The second hydroconverted effluent 18 is then sent to the common separation system C to to be separated with the first hydroconverted effluent 12 from the first hydroconversion step a) during the fractionation step d), in order to recover the compounds hydrocarbons produced during the first and second hydroconversion stages and boiling in the distillate range, as mentioned in stages c) and d) described above.

The hydroconversion catalyst of this second hydroconversion stage b) may be identical to or different from that of the first hydroconversion stage a).

A suitable catalyst for this second hydroconversion step b) is as described for the first hydroconversion step a).

The second hydroconversion stage A ₂ can comprise one or more reactors which can be arranged in series and/or in parallel.

A suitable reactor for this second hydroconversion stage can be any type of three-phase hydroconversion reactor, in particular a three-phase reactor with ascending current of liquid and gas of the entrained bed, moving bed, fluidized bed, bubbling bed or fixed bed type.

Asphaltenes can only be present in the DAO to a lesser extent, which allows the possible use of a wider variety of reactor types in this second stage of hydroconversion.

For example, a fixed-bed reactor can be implemented when the metal and Conradson carbon contents of the DAO fraction feeding the second hydroconversion stage are respectively less than 100 ppmw and 10%w.

The number of reactors required may depend on the feedstock flow rate, i.e. the DAO fraction, the overall conversion level of the targeted residue, and the conversion level achieved in the first hydroconversion step.

The temperature and pressure ranges for this second hydroconversion step b) are those described for the first hydroconversion step a).

In one or more embodiments, the operating conditions in the first hydroconversion step a) may be less severe than those used in the second hydroconversion step, thereby avoiding excessive catalyst replacement rates. Therefore, the overall catalyst replacement (i.e. for both hydroconversion steps combined) is also reduced.

For example, the temperature in the first hydroconversion step a) can be lower than the temperature in the second hydroconversion step b). The operating conditions can be selected based on the heavy liquid feed sent to the first hydroconversion stage, including the content of impurities in said feed and the desired level of impurities to be removed in the first hydroconversion stage, among other factors.

According to one or more alternative embodiments, at least one of the operating temperature and the operating pressure in the first hydroconversion stage A ₁ is higher than that applied in the second hydroconversion stage A ₂ .

The hourly volume rate (VVH) for this second hydroconversion step can be between 0.1 h ^-1 and 5.0 h ^-1 , preferably between 0.2 h ^-1 and 2.0 h ^-1 , the hourly volumetric speed being the liquid feed rate of step b) of hydroconversion taken under standard temperature and pressure conditions (typically 15° C. and 1 atm, i.e. 0.101325 MPa), relative to the total volume of the or reactors used in step b).

In the process according to the invention, although the severity of the operation is deliberately limited during the first hydroconversion step a) in order to reduce the risk of fouling, the overall conversion of the residue in the process, i.e. the conversion at the end of the two stages of hydroconversion, is high, and can go beyond 80% by weight, in particular thanks to the partial conversion of the asphaltenes in the first stage of hydroconversion and the hydroconversion of the DAO fraction during of the second hydroconversion step b). Overall conversions of the residue of at least 80% by weight, even of at least 85% by weight, and even of at least 90% by weight or beyond can be achieved with the process according to the invention, while reducing the problems of instability and the formation of sediments that can occur during the mixing of the hydroconverted effluents from the two hydroconversion stages and sent to the fractionation, which represents a significant advantage in terms of reliability, operability and simplified maintenance, and associated economic gains.

The process according to the invention therefore comprises a solvent deasphalting unit D downstream of a first hydroconversion stage A ₁ where a first step of hydroconversion of the residue is carried out in which the residence time of the treated residue is optimized, this step thus allowing the conversion of at least part of the asphaltenes into lighter and recoverable hydrocarbon compounds while minimizing the risk of formation of sediments during the mixing with the hydroconverted DAO in a second hydroconversion step. The hydroconversion of the asphaltenes in the first hydroconversion stage a) can make it possible to achieve an overall conversion of the residue greater than about 60% by weight, or even greater than 85% by weight; and advantageously greater than 90% by weight, or even greater than 95%, while minimizing the risks of fouling in the common separation unit (C) receiving the hydroconverted effluents. In addition, due to the conversion of at least part of the asphaltenes upstream (from the deasphalting), the size required for the solvent deasphalting units used in the process according to the invention can be lower than that which would be required when the entire residue is initially to be treated.

There illustrates an example of a process according to the invention. As described in connection with the , the first hydroconverted effluent 12 from the first hydroconversion step a) and the second hydroconverted effluent 18 from the second hydroconversion step b) are sent to the separation system C. According to this example, the separation system C comprises at least one high-temperature high-pressure separator C1 (separator called "HP/HT" or "HHPS" for "Hot High Pressure Separator" in English), an atmospheric distillation column C2, and a vacuum distillation column C3. The separation system C can also comprise a cooling, purification and gas compression system R. Other separators, not shown, can be part of the separation system C, such as for example a high temperature medium pressure separator (separator called “MP/HT”, or “HMPS” for “Hot Medium Pressure Separator” in English) downstream of the HP/HT separator and upstream of the distillation column, high pressure medium temperature separators (separator called “HP/MT “, or “WHPS” for “Warm High Pressure Separator” in English) and high pressure low temperature (separator called “HP/BT”, or “CHPS” for “Cold High Pressure Separator” in English) on the gas circuit, a low temperature medium pressure separator (separator called “MP/BT”, or “CMPS” for “Cold Medium Pressure Separator” in English) on the condensed hydrocarbon outlet line 22 downstream of R.

The HP/HT separator C ₁ makes it possible to separate the hydroconverted effluents into a gas phase product 19 and a liquid phase product 20.

The gas phase product 19 can be directed to the gas cooling, purification and compression system R. A gas 21 containing hydrogen can thus be recovered from the system, part of which can be recycled to the reactors of the first and second hydroconversion stages A ₁ and A ₂ . Hydrocarbons condensed during cooling and purification 22 can be recovered and combined with liquid phase product 20 for further processing. The combined liquid stream 23 can then be introduced into an atmospheric distillation column C ₂ to separate said stream into a first light fraction 24 comprising hydrocarbon compounds boiling in a range of atmospheric distillates and a first heavy fraction 25 comprising hydrocarbon compounds having a boiling point of at least 300°C. The first light fraction 24 and the first heavy fraction 25 can be recovered by different lines, as illustrated.

The first heavy fraction 25 can then be fed to a C ₃ vacuum distillation system to separate the first bottoms fraction 25 into a second light fraction 26 comprising hydrocarbon compounds boiling in a range of vacuum distillates and a second heavy fraction 14 comprising hydrocarbon compounds having a boiling point of at least 450°C. The second light fraction 26 and the second heavy fraction 14 can be recovered by different lines, as illustrated. The second heavy fraction 14 is sent to the solvent deasphalting unit D.

It may be necessary to reduce the temperature of the second heavy fraction 14 before supplying the deasphalting unit with solvent D. The second heavy fraction 14 can thus be cooled by heat exchange. Due to the greater risk of fouling of indirect heat exchange systems, a direct heat exchange is preferred, and can be carried out by bringing the second heavy fraction 14 into contact, for example, with at least a part 28 of the first heavy fraction 25 and/or part 27 of residue 10.

As illustrated on the , the method according to the invention may comprise a dedicated system for cooling, purifying and compressing gas R. According to other embodiments, the product in the gaseous phase 19 recovered at the top of the HP/HT separator C1, or at the least part of it, can be treated in a common gas cooling, purification and compression system, integrating the treatment of gas coming from other hydrorefining units on the site.

Although not illustrated, at least a portion of the asphalt 16 may be recycled to the first stage of hydroconversion reactor A ₁ according to certain embodiments. The upgrading or use of the asphalt 16 can be carried out using other methods known to those skilled in the art. For example, the asphalt 16 can be mixed with LCO, HCO cuts or residues from FCC (“slurry oil”) units to be used as fuel, or be treated alone or in combination with other fillers. in delayed coking or gasification units, or be transformed into asphalt granules.

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.

Example 1 is not in accordance with the invention. Example 2 is in accordance with the invention.

Charge

The heavy hydrocarbon feedstock is a "Straight Run" vacuum residue (RSV) from Ural crude oil, the main characteristics of which are presented in Table 1 below.

First stage load hydroconversion AT ₁ Charge RSV Urals Content at 540°C+ (i.e. boiling at 540°C or more) %weight 77.9 Sulfur %weight 2.72 Nitrogen %weight 0.60 Nickel + Vanadium ppm weight 236 Carbon Conradson %weight 17.0 C ₇ Asphaltenes %weight 6.8 sediments %weight < 0.01

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

Example 1: Process according to the state of the art (not in accordance with 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 hydroconversion stages each comprising a reactor operating in an ebullated bed and working at conventional hourly volume velocities (between 0, 1:00 ^a.m. and 5:00 ^a.m. ).

First floor of hydroconversion

The fresh feed from Table 1 is sent in its entirety to a first hydroconversion stage A ₁ in the presence of hydrogen, said stage comprising two three-phase reactors R1 and R2 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 relative to the total mass of the catalyst. The two reactors are operated in an ebullated bed operating with an ascending current of liquid and gas.

The operating conditions applied in the first hydroconversion stage are presented in Table 2 below.

Operating conditions of the first stage of hydroconversion AT ₁ VVH reactor (R1+R2) h ^-1 0.217 Temperature R1 / Temperature R2 °C 415 / 417 Total pressure R1 / Total pressure R2 MPa 16.0 / 15.6 Quantity of hydrogen entering R1 Nm ³ /m ³ 650

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced content of C ₇ asphaltenes, Conradson carbon, nitrogen and sulfur. The yield structure at the outlet of the first stage and the overall performances are given in Table 3, together with the composition of the total liquid and the sediment content of the atmospheric residue. The conversion of the 540° C.+ fraction at the outlet of the first hydroconversion stage is 55% by weight. The atmospheric residue sent to the separation system contains 0.19% by weight of sediment.

Effluent from the first stage of hydroconversion AT ₁ Gas % weight / load 4.7 Naphtha (C5 – 180°C) % weight / load 4.9 Diesel (180°C – 350°C) % weight / load 16.3 Distillate under vacuum (350°C – 540°C) % weight / load 40.3 Vacuum residue (540°C+) % weight / load 35.2 Hydrogen consumption % weight / load 1.39 HDC540°C+ % weight 55 HDS % weight 80 HDN % weight 28 HDCCR % weight 62 HDAsC ₇ % weight 66 Sulfur %weight 0.56 Nitrogen %weight 0.45 Nickel + Vanadium ppm weight 24 Carbon Conradson %weight 6.6 C ₇ Asphaltenes %weight 2.4 Atmospheric residue sediments %weight 0.19

Second floor of hydroconversion

The DAO cut from the deasphalter, the properties of which are given in Table 4, is sent in its entirety to a second hydroconversion stage A ₂ in the presence of hydrogen, said stage comprising two three-phase reactors R3 and R4 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 reactors are operated in an ebullated bed operating with an ascending current of liquid and gas.

Second stage load hydroconversion AT ₂ Charge CAD Content at 540°C+ %weight 76.7 Sulfur %weight 0.77 Nitrogen %weight 0.46 Nickel + Vanadium ppm weight < 2 Carbon Conradson %weight 6.4 C ₇ Asphaltenes %weight 0.11 Atmospheric residue sediments %weight < 0.01

The operating conditions applied in the first hydroconversion stage are presented in Table 5 below.

Operating conditions of the second stage of hydroconversion AT ₂ VVH reactor (R3+R4) h ^-1 0.36 R3 temperature / R4 temperature °C 440 / 440 Total pressure R3 / Total pressure R4 MPa 16.0 / 15.6 Quantity of hydrogen entering R3 Nm ³ /m ³ 600

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced content of C ₇ asphaltenes, Conradson carbon, nitrogen and sulfur. The yield structure at the outlet of the second stage and the overall performance are given in Table 6, together with the composition of the total liquid and the sediment content of the atmospheric residue. The conversion of the 540° C.+ fraction at the outlet of the second hydroconversion stage is 78% by weight. The atmospheric residue sent to the separation system does not contain sediment.

Effluent from the second stage of hydroconversion AT ₂ Gas % weight / DAO 6.7 Naphtha (C5 – 180°C) % weight / DAO 13.5 Diesel (180°C – 350°C) % weight / DAO 27.3 Distillate under vacuum (350°C – 540°C) % weight / DAO 39.4 Vacuum residue (540°C+) % weight / DAO 14.5 Hydrogen consumption % weight / DAO 1.29 HDC540°C+ % weight 78 HDS % weight 98 HDN % weight 75 HDCCR % weight 87 HDAsC ₇ % weight N / A Sulfur %weight 0.02 Nitrogen %weight 0.12 Nickel + Vanadium ppm weight < 2 Carbon Conradson %weight 0.9 C ₇ Asphaltenes %weight < 0.05 Atmospheric residue sediments %weight 0.03

Mixing of the first and second effluents

The reaction product from the first hydroconversion stage a), i.e. the first hydroconverted effluent, and the reaction product from the second hydroconversion stage b) are sent to the common separation system C, in order to undergo fractionation. The structure of normalized yields and the composition of the liquid entering the separation system are given in Table 7.

Common Split System Charge VS Gas % weight 5.1 Naphtha (C5 – 180°C) % weight 6.7 Diesel (180°C – 350°C) % weight 18.6 Distillate under vacuum (350°C – 540°C) % weight 39.6 Vacuum residue (540°C+) % weight 30.1 Sulfur %weight 0.44 Nitrogen %weight 0.38 Nickel + Vanadium ppm weight 19 Carbon Conradson %weight 5.3 C ₇ Asphaltenes %weight 1.9 Atmospheric residue sediments %weight 0.50

Note that the sediment content has increased significantly. Indeed, the sediment content of the total liquid is 0.19% by weight in the atmospheric residue of the first stage of hydroconversion and is below the detection limit in the atmospheric residue of the second stage of hydroconversion. Because of the incompatibility of the two effluents, their mixture contains 0.50% weight of sediment in the atmospheric residue, an increase of 150%. This will lead to very heavy fouling of the equipment (separators, distillation columns, exchangers, etc.) of the separation section.

Deasphalting

The vacuum residue that comes out of the vacuum distillation of the common separation system C is then sent to the deasphalting section D. The operating conditions of the deasphalting section D are given in table 8.

Operating conditions of the section of deasphalting D Solvent - Cup _C4 Mean temperature °C 95 Total pressure MPa 3 Solvent/filler ratio m ³ /m ³ 8

The yields of deasphalted oil (“DAO” cut) and asphalt are given in Table 9, while the composition of the DAO is given in Table 4.

Effluent from the section of deasphalting D CAD % weight / RSV 71 Asphalt % weight / RSV 29

The DAO cut here is sent in full to the inlet of the second hydroconversion stage.

Global Schema Conversion

With this configuration, which is not in accordance with the invention, the diagram makes it possible to convert nearly 79% of the 540°C+ fraction, as indicated in table 10.

Global conversion of plan D Entrance (reference 100) Total load Urals t/h 100 Input flow at 540°C+ t/h 77.9 Exits Output flow at 540°C+ in the VGO t/h 6.3 Output rate at 540°C+ in asphalt t/h 10.6 Conversion from 540°C+ Global Conversion %weight 78.3

On the other hand, the very high sediment content at the inlet of the separation section leads to very heavy fouling of the equipment (separators, distillation columns, exchangers, etc.) of this section, and therefore requires regular shutdowns. for cleaning.

Example 2: Process according to the invention (in accordance with the invention)

This example illustrates a process for the hydroconversion of a heavy charge of hydrocarbons according to the invention comprising two hydroconversion stages each comprising a reactor operating in an ebullated bed and working at hourly volume velocities according to the invention (below 0 ,1 h ^-1 concerning the first stage of hydroconversion).

First floor of hydroconversion

The fresh feed from Table 1 is sent in its entirety to a first hydroconversion stage A ₁ in the presence of hydrogen, said stage comprising two three-phase reactors R1 and R2 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 relative to the total mass of the catalyst. The two reactors are operated in an ebullated bed operating with an ascending current of liquid and gas.

The operating conditions applied in the first hydroconversion stage are presented in Table 11 below.

Operating conditions of the first stage of hydroconversion AT ₁ VVH reactor (R1+R2) h ^-1 0.079 Temperature R1 / Temperature R2 °C 415 / 417 Total pressure R1 / Total pressure R2 MPa 16.0 / 15.6 Quantity of hydrogen entering R1 Nm ³ /m ³ 650

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced content of C ₇ asphaltenes, Conradson carbon, nitrogen and sulfur. The yield structure at the outlet of the first stage and the overall performances are given in Table 12, together with the composition of the total liquid and the sediment content of the atmospheric residue. The conversion of the 540° C.+ fraction at the outlet of the first hydroconversion stage is 83% by weight. The atmospheric residue sent to the separation system contains 0.04% by weight of sediment.

Effluent from the first stage of hydroconversion AT ₁ Gas % weight / load 8.7 Naphtha (C5 – 180°C) % weight / load 13.5 Diesel (180°C – 350°C) % weight / load 30.7 Distillate under vacuum (350°C – 540°C) % weight / load 36.1 Vacuum residue (540°C+) % weight / load 13.3 Hydrogen consumption % weight / load 2.34 HDC540°C+ % weight 83 HDS % weight 94 HDN % weight 57 HDCCR % weight 87 HDAsC ₇ % weight 91 Sulfur %weight 0.18 Nitrogen %weight 0.27 Nickel + Vanadium ppm weight 3 Carbon Conradson %weight 2.4 C ₇ Asphaltenes %weight 0.6 Atmospheric residue sediments %weight 0.04

Second floor of hydroconversion

The DAO cut from the deasphaltor, the properties of which are given in Table 13, is sent in its entirety to a second hydroconversion stage A ₂ in the presence of hydrogen, said stage comprising two three-phase reactors R3 and R4 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 reactors are operated in an ebullated bed operating with an ascending current of liquid and gas.

Second stage load hydroconversion AT ₂ Charge CAD Content at 540°C+ %weight 77 Sulfur %weight 0.81 Nitrogen %weight 0.52 Nickel + Vanadium ppm weight < 2 Carbon Conradson %weight 8.2 C ₇ Asphaltenes %weight 0.11 Atmospheric residue sediments %weight < 0.01

The operating conditions applied in the first hydroconversion stage are presented in Table 14 below.

Operating conditions of the second stage of hydroconversion AT ₂ VVH reactor (R3+R4) h ^-1 0.39 R3 temperature / R4 temperature °C 440 / 440 Total pressure R3 / Total pressure R4 MPa 16.0 / 15.6 Quantity of hydrogen entering R3 Nm ³ /m ³ 600

These operating conditions make it possible to obtain a hydroconverted liquid effluent with a reduced content of C ₇ asphaltenes, Conradson carbon, nitrogen and sulfur. The yield structure at the outlet of the second stage and the overall performance are given in Table 15, together with the composition of the total liquid and the sediment content of the atmospheric residue. The conversion of the 540° C.+ fraction at the outlet of the second hydroconversion stage is 79% by weight. The atmospheric residue sent to the separation system does not contain sediment.

Effluent from the second stage of hydroconversion AT ₂ Gas % weight / DAO 6.6 Naphtha (C5 – 180°C) % weight / DAO 14.3 Diesel (180°C – 350°C) % weight / DAO 28.5 Distillate under vacuum (350°C – 540°C) % weight / DAO 37.7 Vacuum residue (540°C+) % weight / DAO 14.3 Hydrogen consumption % weight / DAO 1.41 HDC540°C+ % weight 79 HDS % weight 96 HDN % weight 70 HDCCR % weight 85 HDAsC ₇ % weight N / A Sulfur %weight 0.03 Nitrogen %weight 0.16 Nickel + Vanadium ppm weight < 2 Carbon Conradson %weight 1.3 C ₇ Asphaltenes %weight < 0.05 Atmospheric residue sediments %weight < 0.01

Mixing of the first and second effluents

The reaction product from the first hydroconversion stage a), i.e. the first hydroconverted effluent, and the reaction product from the second hydroconversion stage b) are sent to the common separation system C, in order to undergo fractionation. The structure of normalized yields and the composition of the liquid entering the separation system are given in Table 16.

Common Split System Charge VS Gas % weight 8.3 Naphtha (C5 – 180°C) % weight 13.3 Diesel (180°C – 350°C) % weight 29.8 Distillate under vacuum (350°C – 540°C) % weight 35.5 Vacuum residue (540°C+) % weight 13.1 Sulfur %weight 0.16 Nitrogen %weight 0.26 Nickel + Vanadium ppm weight 2 Carbon Conradson %weight 2.3 C ₇ Asphaltenes %weight 0.6 Atmospheric residue sediments %weight 0.14

It is noted that the sediment content has decreased due to the dilution effect. Indeed, the sediment content is 0.16% by weight in the atmospheric residue of the first stage of hydroconversion and is below the detection limit in the atmospheric residue of the second stage of hydroconversion. The very high conversion of asphaltenes in the first stage of hydroconversion made it possible to avoid incompatibility between the two effluents. Thus, their mixture contains 0.14% by weight of sediment in the atmospheric residue, ie a lower sediment content than that of the atmospheric residue of the first reactor.

Deasphalting

The vacuum residue that comes out of the vacuum distillation of the common separation system C is then sent to the deasphalting section D. The operating conditions of the deasphalting section D are given in table 17.

Operating conditions of the section of deasphalting D Solvent - Cup _C4 Mean temperature °C 95 Total pressure MPa 3 Solvent/filler ratio m ³ /m ³ 8

The yields of deasphalted oil (“DAO” cut) and asphalt are given in Table 18, while the composition of the DAO is given in Table 13.

Effluent from the section of deasphalting D CAD % weight / RSV 74 Asphalt % weight / RSV 26

The DAO cut here is sent in full to the inlet of the second hydroconversion stage.

Global Schema Conversion

With this configuration, in accordance with the invention, the scheme makes it possible to convert more than 93% of the 540°C+ fraction, as indicated in table 19.

Global conversion of plan D Entrance (reference 100) Total load Urals t/h 100 Input flow at 540°C+ t/h 77.9 Exits Output flow at 540°C+ in the VGO t/h 1.3 Output rate at 540°C+ in asphalt t/h 4.0 Conversion from 540°C+ Global conversion %weight 93.3

In addition, the very low sediment content at the inlet of the separation section leads to a greatly improved operability of this section thanks to a greatly reduced fouling of this equipment.

Claims (17)

Process for converting a heavy hydrocarbon feedstock containing a fraction of at least 50% having a boiling point of at least 300°C, comprising the following steps:
a) the hydroconversion of said heavy hydrocarbon feedstock (10) in a first hydroconversion stage (A ₁ ) to form a first effluent (12);
b) the hydroconversion of a deasphalted oil fraction (15) in a second hydroconversion stage (A ₂ ) in order to form a second effluent (18);
c) sending said first and second effluents to a separation system (C);
d) fractionating said mixed first and second effluents in said separation system (C) to form at least one distillate hydrocarbon fraction (13) and one residue hydrocarbon fraction (14);
e) sending at least part of the residue hydrocarbon fraction (14) to a solvent deasphalting unit (D) to obtain the deasphalted oil fraction (15) and an asphalt fraction (16) ,
wherein the hourly volume velocity for step a) is between 0.05 h ^-1 and 0.09 h ^-1 . Process according to Claim 1, in which the hourly volume velocity implemented in step a) is between 0.05 h ^-1 and 0.08 h ^-1 . Process according to any one of the preceding claims, in which at least one of the operating temperature and the operating pressure in the second hydroconversion stage (A ₂ ) in step b) is higher than the operating temperature and the operating pressure in the first hydroconversion stage (A ₁ ) in step a). Process according to any one of claims 1 and 2, in which at least one of the operating temperature and the operating pressure in the second hydroconversion stage (A ₂ ) in step b) is lower than the operating temperature and the operating pressure in the first hydroconversion stage (A ₁ ) in step a). Process according to any one of the preceding claims, in which the hourly volume velocity implemented in step b) is between 0.1 h ^-1 and 5.0 h ^-1 . Process according to any one of the preceding claims, in which at least part of the asphaltenes contained in the said heavy hydrocarbon charge is converted in the first hydroconversion stage (A ₁ ) in step a). A process according to any preceding claim, wherein said residue hydrocarbon fraction (14) from step d) comprises hydrocarbon compounds having a boiling point of at least 300°C. Process according to any one of the preceding claims, in which the first hydroconversion stage (A ₁ ) comprises a single bubbling bed reactor. Process according to any one of the preceding claims, in which the second hydroconversion stage (A ₂ ) comprises at least one bubbling bed reactor and/or one fixed bed reactor. Process according to any of the preceding claims, in which step d) of fractionation comprises:
- the separation of the first and second effluents (12, 18) in a high pressure and high temperature separator (C ₁ ) in order to obtain a gas phase product (19) and a liquid phase product (20);
- the separation of the liquid phase product (20) in an atmospheric distillation column (C ₂ ) in order to recover a first light fraction (24) comprising hydrocarbon compounds boiling in a range of atmospheric distillates and a first heavy fraction (25) comprising hydrocarbon compounds having a boiling point of at least 300°C;
- the separation of the heavy fraction (25) in a vacuum distillation column (C ₃ ) in order to recover a second light fraction (26) comprising hydrocarbon compounds boiling in a range of vacuum distillates and a second heavy fraction (14 ) comprising hydrocarbon compounds having a boiling point of at least 450°C; And
- sending the second heavy fraction (14) to the solvent deasphalting unit (D) in step e) as residue hydrocarbon fraction,
wherein the hydroconversion step a) of said heavy hydrocarbon feedstock comprises:
- sending hydrogen (11) and said heavy hydrocarbon charge (10) to a first hydroconversion reactor containing a first hydrocracking catalyst;
- bringing said heavy hydrocarbon charge (10) and hydrogen (11) into contact in the presence of the first hydrocracking catalyst under temperature and pressure conditions making it possible to carry out the conversion of at least a portion of said heavy hydrocarbon feedstock;
- recovering the first effluent (12) from the first hydroconversion reactor;
and wherein the hydroconversion step b) of the deasphalted oil fraction (15) comprises:
- sending hydrogen (17) and the deasphalted oil fraction (15) to a second hydroconversion reactor containing a second hydrocracking catalyst;
- bringing the deasphalted oil fraction (15) and hydrogen (17) into contact in the presence of the second hydrocracking catalyst under temperature and pressure conditions making it possible to carry out the conversion of at least a portion of deasphalted oil; And
- the recovery of the second effluent (18) from the second hydroconversion reactor. A method according to claim 10, further comprising cooling the gas phase product (19) to recover a hydrogen-containing gas fraction (21) and a distillate fraction (22); and sending the distillate fraction (22) to the atmospheric distillation column (C ₂ ). A method according to claim 11, further comprising recycling at least a portion of the hydrogen-containing gas fraction (21) to at least one of said first hydroconversion reactor and second hydroconversion reactor. Process according to one of claims 10 to 12, further comprising cooling the second heavy fraction (14) via direct heat exchange with at least one of a portion of the residue (10) and a portion (28 ) of the first heavy fraction (25). A process according to any preceding claim, wherein the hydrocarbon residue fraction (14) comprises hydrocarbon compounds having a boiling point of at least 450°C. Process according to any one of the preceding claims, in which the hydroconversion stage a) is carried out under an absolute pressure of between 2 and 35 MPa, at a temperature of between 300°C and 550°C, and in a quantity of hydrogen mixed with the heavy hydrocarbon charge of between 50 and 5000 Nm ³ /m ³ of heavy hydrocarbon charge. Process according to any of the preceding claims, wherein said heavy hydrocarbon feedstock (10) contains a fraction of at least 80% having a boiling point of at least 300°C, and is preferably a crude oil or consists 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 the vacuum distillation of a crude oil. A process according to any preceding claim, wherein said heavy hydrocarbon feedstock has a sulfur content of at least 0.1 wt%, a Conradson carbon content of at least 0.5 wt%, an asphaltene content C ₇ of at least 1% by weight, and a metal content of at least 20 ppm by weight.