CN114058404A

CN114058404A - Process for hydrogenating a conversion residue with several hydroconversion stages, incorporating a deasphalting step

Info

Publication number: CN114058404A
Application number: CN202110883353.0A
Authority: CN
Inventors: J·马克斯; J·韦斯特拉特
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2020-07-30
Filing date: 2021-07-30
Publication date: 2022-02-18
Also published as: FR3113062B1; FR3113062A1; SA121420933B1

Abstract

A residuum hydroconversion process incorporating a deasphalting step having several hydroconversion stages is disclosed. The present invention relates to a process for converting a heavy hydrocarbon feedstock (10) comprising: a) in the first hydroconversion stage (A)₁) Hydroconverting said feedstock (10) to form a first effluent (12); b) in the second hydroconversion stage (A)₂) Hydroconverting the DAO (15) to form a second effluent (18); c) sending the first effluent and the second effluent to a separation system (C); d) fractionating the first and second effluents as a mixture in the separation system (C) to form at least one hydrocarbon distillate fraction (13) and one hydrocarbon residue fraction (14); e) sending at least part of fraction (14) to a solvent deasphalting unit (D) to obtain DAO (15) and an asphalt fraction (D)16) Wherein the liquid hourly space velocity of the step a) is 0.05-0.09h^‑1。

Description

Process for hydrogenating a conversion residue with several hydroconversion stages, incorporating a deasphalting step

Technical Field

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

These feedstocks may be crude oils or may result from the distillation and/or refining of crude oils, typically residues from the atmospheric and/or vacuum distillation of crude oils.

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

Background

Hydrocarbon compounds can be used for a variety of purposes. In particular, hydrocarbon compounds are particularly useful as fuels, solvents, degreasers, detergents, and polymer precursors. Currently the most important source of hydrocarbon compounds is crude oil. Refining crude oil into separate hydrocarbon compound fractions is a well known processing technique.

Crude oils vary widely in their composition, and in their physical and chemical properties. The properties of the heavy crude oil are: relatively high viscosity, low API density, and a high percentage of high boiling point components (e.g., having a normal boiling point of at least 540 ℃).

The average hydrogen to carbon ratio of a refined petroleum product is typically higher than the petroleum fraction from which it is derived, on a molecular basis. Thus, upgrading of hydrocarbon fractions in refineries is generally classified into one of two categories: hydrogen addition and carbon removal. The hydrogenation is carried out by processes such as hydrotreating (e.g., desulfurization of atmospheric residue or "ARDS" (atmospheric residue desulfurization)) and hydroconversion (also referred to as "residue hydrocracking"). Carbon removal processes typically produce a material stream with a high content of removed carbon, which may be a liquid or a solid, such as coke deposits. Carbon removal is performed by processes such as Fluid Catalytic Cracking (FCC) and delayed coking.

Hydroconversion processes can be used to upgrade higher boiling compounds (e.g., residues) typically present in heavy crude oils by converting the higher boiling compounds (e.g., residues) typically present in heavy crude oils to lower boiling compounds. Thus, at least a portion of the residuum sent to the hydroconversion reactor is converted to lower boiling products. The conversion of the residue corresponds to the fraction of the converted residue. The unreacted residuum (commonly referred to as UCO, standing for "unconverted oil") can be recovered and either discharged from the hydroconversion process or recycled in the hydroconversion reactor to increase the overall conversion of the residuum.

The conversion of the resid in the hydroconversion reactor can depend on various factors, including the composition of the feedstock (i.e., resid); the type of reactor used; reaction (operating conditions including temperature and pressure) severity; liquid hourly space velocity or "LHSV"; and the type and properties of the catalyst. The Liquid Hourly Space Velocity (LHSV) with respect to the reactor is defined as the ratio of the volumetric flow rate of the liquid feedstock into the reactor relative to the reactor volume measured at ambient conditions, also known as standard conditions (typically at 15 ℃ and 1atm, i.e. 0.101325 MPa). The liquid hourly space velocity with respect to the catalyst is defined as the ratio of the volumetric flow rate of the liquid feedstock entering the reactor relative to the volume of catalyst in the reactor measured at ambient conditions (typically at 15 ℃ and 1atm, i.e. 0.101325 MPa). The liquid hourly space velocity is therefore given in units h^-1And inversely proportional to the residence time in the reactor or catalytic bed.

Reaction severity can be used to increase conversion, i.e., more severe operating conditions can increase conversion of the feedstock. However, as the severity of the reaction increases, side reactions can occur within the hydroconversion reactor, producing various byproducts in the form of coke precursors, deposits, other deposits, and byproducts that form a secondary liquid phase (commonly referred to as a "mesophase"). Excessive formation of coke precursors deactivates hydroconversion catalysts by poisoning them and can hinder their subsequent processing. Deactivation of the hydroconversion catalyst can not only significantly reduce the conversion of the residuum, but can also require more frequent replacement of the expensive catalyst. The formation of a secondary liquid phase not only deactivates the hydroconversion catalyst, thereby leading to higher catalyst consumption, but also can defluidize the catalyst, and thus also limits the maximum conversion. This defluidization leads to the formation of "hot zones" within the catalyst bed, which exacerbate coke formation, which further deactivates the hydroconversion catalyst. Excessive formation of deposits deactivates the hydroconversion catalyst by poisoning it and fouls items of equipment downstream of the reactor, such as separators and distillation columns.

The formation of deposits in the hydroconversion reactor also depends on the quality of the feedstock fed to the reactor. For example, asphaltenes that may be present in the feedstock sent to the hydroconversion reactor are particularly prone to deposit formation when subjected to severe operating conditions. Thus, it may be desirable to separate asphaltenes from the resid to increase conversion.

In order to remove asphaltenes from heavy hydrocarbon feedstocks of the residuum type, it is known to employ a Solvent Deasphalting (SDA) process. Solvent deasphalting generally involves the physical separation of less polar hydrocarbons from more polar hydrocarbons including asphaltenes (based on their relative affinity for the solvent). Light solvents, e.g. C₃To C₇Hydrocarbons, which may be used to dissolve or suspend lighter hydrocarbons, form what are commonly referred to as deasphalted oils or "DAOs," and may precipitate asphaltenes. The phases are then separated and the solvent is recovered. Additional information on solvent Deasphalting conditions, Solvents and steps performed can be obtained in patent US 4239616, patent US 4440633, patent US 4354922, patent US 4354928 and patent US 4536283, and chapter 15 "Deasphalting with Parafine Solvents", published by É conditions in 2011 by the book "Heavy crop Oils: From geography to Upgrading, An Overview".

Methods are also known that incorporate solvent deasphalting and hydroconversion processes to remove asphaltenes from residua. Examples of such integration methods are described, for example, in patent US 7214308, patent US 7279090 and patent US 7691256. These patents describe contacting the residuum in a deasphalting system with a solvent to separate asphaltenes from the deasphalted oil. The DAO and asphaltenes are then sent separately to separate hydroconversion reactor systems.

Given that DAO and asphaltenes are converted separately, a moderate overall conversion of these residues of about 65% to 70% can be obtained with such a process, as described in patent US 7214308. Hydroconversion of asphaltenes as described, however, is carried out at high conversion under severe operating conditions and may present particular problems as discussed above. For example, to increase conversion, the hydroconversion reactor to which the asphaltenes are sent is operated under severe conditions, which can also lead to high formation of deposits and high replacement of the catalyst. On the other hand, running a reactor for hydroconversion of asphaltenes under less severe conditions will suppress the formation of deposits, but the conversion per pass of asphaltenes will be low. To achieve a higher overall conversion of the feedstock (i.e., resid), these processes typically require a high degree of recycle of the unreacted resid to the hydroconversion reactor or reactors. Such high volume recycle can significantly increase the size of the upstream hydroconversion reactor and/or solvent deasphalting system.

A residuum hydroconversion process is known that addresses the above-mentioned problems, and its objective is to provide a high overall residuum conversion while reducing the overall size of the hydroconversion reactor or deasphalting unit equipment items, and while minimizing the frequency of catalyst replacement. Thus, patents US 8287720, US 9441174 and US 9873839 describe an integrated process for the hydroconversion and deasphalting of residues comprising several hydroconversion stages ("multistage"), and in particular a process comprising the following steps: hydroconverting a residue in a first reaction stage to form a first hydroconversion effluent, hydroconverting a DAO fraction in a second reaction stage to form a second effluent, fractionating the first hydroconversion effluent and the second hydroconversion effluent to form at least one distillate fraction and one residue fraction, and sending the residue fraction to a unit for deasphalting by means of at least one solvent to obtain a DAO fraction and an asphalt fraction.

However, the mixture of first and second hydroconversion effluents sent to the fractionation step can generate chemical instabilities in the treatments downstream of the fractionation, as already described above, and can lead to significant deposit formation, sources of various problems of fouling type, deactivation of the catalyst, etc.

This is because it has been demonstrated that the mixing of certain hydrocarbon fractions (e.g., certain distillate fractions and residual oil fractions resulting from the fractionation of the hydroconversion effluent) during hydroconversion of heavy hydrocarbon feedstocks can lead to chemical instability and to significant additional sediment formation. Surprisingly, it has also been demonstrated that judicious choice of the operating conditions of the different steps can prevent the generation of such new deposits.

It is therefore an object of the present invention to provide an improved multistage process for the hydroconversion of heavy hydrocarbon feedstocks of the residuum type as described in patent US 8287720, patent US 9441174 and patent US 9873839, which makes it possible to achieve high overall conversion levels while minimizing the formation of deposits and the risk of fouling of the equipment items.

Disclosure of Invention

Thus, in order to achieve at least one of the above objects, in particular according to a first aspect, the present invention provides a process for converting a heavy hydrocarbon feedstock containing a fraction at least 50% of which have a boiling point of at least 300 ℃, said process comprising the steps of:

a) hydroconverting the heavy hydrocarbon feedstock in a first hydroconversion stage to form a first effluent;

b) hydroconverting the deasphalted oil fraction in a second hydroconversion stage to form a second effluent;

c) passing the first and second effluents to a separation system;

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

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

wherein the liquid hourly space velocity of step a) is 0.05h^-1-0.09h^-1。

According to one or more embodiments, the liquid hourly space velocity employed in step a) is 0.05h^-1-0.08h^-1。

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

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

According to one or more embodiments, the liquid hourly space velocity employed in step b) is 0.1h^-1-5.0h^-1。

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

According to one or more embodiments, the first hydroconversion stage in step a) is carried out at a temperature and pressure such that the heavy hydrocarbon feedstock is converted to a degree of conversion of from about 30 wt% to about 95 wt% of the heavy hydrocarbon feedstock.

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

According to one or more embodiments, the hydrocarbon residue fraction resulting from step d) comprises hydrocarbon compounds boiling at least 300 ℃.

In accordance with one or more embodiments, the first hydroconversion stage comprises a single ebullated bed reactor.

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

The fractionation step d) comprises:

-separating the first and second effluents at high pressure and high temperature in a separator to obtain a gas-phase product and a liquid-phase product;

-separating the liquid phase product in an atmospheric distillation column to recover a first light fraction comprising hydrocarbon compounds boiling in the atmospheric distillate range and a first heavy fraction comprising hydrocarbon compounds boiling at least 300 ℃;

-separating the heavy fraction in a vacuum distillation column to recover a second light fraction comprising hydrocarbon compounds boiling in the vacuum distillate range and a second heavy fraction comprising hydrocarbon compounds boiling at least 450 ℃; and

-sending the second heavy fraction as a hydrocarbon residue fraction to the solvent deasphalting unit in step e),

wherein step a) of hydroconverting the heavy hydrocarbon feedstock comprises:

-sending hydrogen and a heavy hydrocarbon feedstock to a first hydroconversion reactor containing a first hydrocracking catalyst;

-contacting the heavy hydrocarbon feedstock with hydrogen in the presence of a first hydrocracking catalyst under temperature and pressure conditions that allow at least a portion of the heavy hydrocarbon feedstock to undergo conversion;

-recovering a first effluent from the first hydroconversion reactor;

and wherein step b) of hydroconverting the deasphalted oil fraction comprises:

-passing hydrogen and the deasphalted fraction to a second hydroconversion reactor containing a second hydrocracking catalyst;

-contacting the deasphalted oil fraction with hydrogen in the presence of a second hydrocracking catalyst under temperature and pressure conditions allowing at least a portion of the deasphalted oil to undergo conversion; and

-recovering a second effluent resulting from the second hydroconversion reactor.

In accordance with one or more embodiments, the method further includes cooling the vapor phase product to recover a gaseous fraction containing hydrogen and a distillate fraction, and sending 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 hydrogen-containing gas fraction in at least one of the first hydroconversion reactor and the second hydroconversion reactor.

In accordance with 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 resid and a portion of the first heavy fraction.

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

According to one or more embodiments, the hydroconversion step a) is carried out at an absolute pressure ranging from 2MPa to 35MPa, at a temperature ranging from 300 ℃ to 550 ℃ and50 to 5000Sm³/m³The amount of hydrogen mixed with the heavy hydrocarbon feedstock.

According to one or more embodiments, the first effluent and the second effluent as a mixture in the separation system in the fractionation step d) do not produce deposits.

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

According to one or more embodiments, the heavy hydrocarbon feedstock has a sulfur content of at least 0.1 wt.%, a Conradson carbon content of at least 0.5 wt.%, a C of at least 1 wt.%₇An asphaltene content and a metal content of at least 20 ppm by weight.

Further subjects and advantages of the invention will become apparent from reading the following description of specific embodiment examples of the invention, given as non-limiting examples, with reference to the attached drawings described below.

Drawings

FIG. 1 is a simplified schematic of a multi-stage hydroconversion and deasphalting process according to the present invention.

Figure 2 is a simplified schematic of an example of a multi-stage hydroconversion and deasphalting process according to the present invention.

In the drawings, like reference characters designate the same or similar elements.

Detailed Description

The present invention relates generally to a process for converting a petroleum feedstock, and in particular to a process for converting a heavy hydrocarbon feedstock containing fractions at least 50% of which have a boiling point of at least 300 ℃. In particular, the invention relates to a process for hydroconversion and deasphalting of such a feedstock, comprising several hydroconversion steps.

According to the invention, the process for converting a heavy hydrocarbon feedstock comprises the following steps, described in detail hereinafter:

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

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

c) sending the first hydroconversion effluent and the second hydroconversion effluent to a separation system (C);

d) fractionating the first hydroconversion effluent and the second hydroconversion effluent as a mixture in a separation system (C) to form at least one hydrocarbon distillate fraction and one hydrocarbon residue fraction;

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

wherein the liquid hourly space velocity in step a) is 0.05h relative to the volume of the reactor^-1-0.09h^-1。

Throughout this specification, unless otherwise indicated, fractions of different hydrocarbon compounds or hydrocarbon fractions are all expressed by weight.

Unless otherwise indicated, temperature and pressure ranges are understood to include limits.

Unless otherwise stated, pressures are expressed in absolute values. The following description of the method according to the invention refers to the general schematic of the method according to the invention of figure 1.

Raw materials

The heavy hydrocarbon feedstock 10 treated in the process according to the invention is a heavy hydrocarbon feedstock containing fractions at least 50 wt.%, preferably at least 80 wt.%, of which have a boiling point of at least 300 ℃, preferably at least 350 ℃ and even more preferably at least 375 ℃.

The feedstock is primarily liquid under the pressure and temperature conditions of the reactor to which it is fed.

The treated heavy feedstock may be crude oil, or may result from the refining of crude oil, typically a residue from the atmospheric and/or vacuum distillation of crude oil.

Preferably, the heavy hydrocarbon feedstock treated in the process according to the invention is a residual hydrocarbon feedstock, also more simply referred to as a residue, which may comprise various fractions of heavy crude oil and fractions resulting from the refining of crude oil. The residue contains a fraction having a boiling point of at least 300 ℃ of at least 50 wt.%, preferably at least 80 wt.%.

For example, the feedstock treated may be an atmospheric distillation residue from a primary fractionation ("SR", standing for "straight run") of crude oil, a vacuum distillation residue from a primary fractionation of crude oil, a residue from an atmospheric or vacuum distillation of a hydrotreated, hydrocracked or hydroconverted effluent, a vacuum distillate ("VGO", standing for "vacuum gas oil") resulting from a primary fractionation of crude oil, a vacuum distillate (VGO) from a hydrotreated, hydrocracked or hydroconverted effluent, a distillate ("cycle oil") or residue ("slurry oil, slurry oil") from a column fractionating an effluent resulting from an FCC unit, a vacuum distillate ("go hchci", standing for "heavy coker gas oil") from a delayed coking unit, a vacuum distillate from a visbreaker unit, a deasphalted oil resulting from a deasphalting unit, a crude oil obtained from a catalytic cracking unit, a crude oil obtained by a catalytic cracking unit, a catalyst, and a catalyst, Bitumen produced by a deasphalting unit, as well as other similar hydrocarbon effluents, or combinations of these, each of which may be produced from primary fractionation, and/or derived from the process, and/or hydroconverted, and/or hydrotreated, or partially desulfurized and/or demetallized.

The feedstocks mentioned generally contain various impurities including asphaltenes, metals, sulfur, nitrogen and conradson carbon ("CCR", standing for "conradson carbon residue"). The treated heavy hydrocarbon feedstock typically has a sulfur content of at least 0.1 wt.%, a Conradson carbon content of at least 0.5 wt.%, a C of at least 1 wt.%₇An asphaltene content and a metal content of at least 20 ppm by weight.

In the present specification, asphaltenes are in particular C₇Asphaltenes according to standard NFT 60-115 or standard ASTM D6560 (describing said C)₇Standard for determination method of asphaltene), which is a compound insoluble in heptane.

A first hydroconversion stage: hydroconversion of heavy liquid feedstock-step a)

The process for converting a heavy hydrocarbon feedstock into lighter hydrocarbon compounds according to the invention first comprises a step a) of hydroconverting said feedstock, including all the asphaltenes contained in said feedstock.

The heavy hydrocarbon feedstock 10 is sent to a first hydroconversion stage A₁To undergo hydroconversion therein and form a reaction product referred to herein as a first hydroconversion effluent 12.

Thus, it is possible to carry out the first hydroconversion stage A₁In which the entire heavy hydrocarbon feedstock 10 (including asphaltenes) is reacted with hydrogen 11 over a hydroconversion catalyst to convert at least a portion of the hydrocarbon compounds to lighter molecules, including at least a portion of the converted asphaltenes.

However, as the severity of the reaction increases, the conversion of heavy feedstocks increases, but it is accompanied by the formation of deposits. These products are not soluble in their environment and can therefore precipitate in lines, equipment items (separators, distillation columns, heat exchangers, filters, etc.) and storage tanks. The content of deposits was measured according to standard IP 375 or standard ASTM D4870 (standard describing the method for determining deposits).

To reduce deposit formation, the first hydroconversion stage may be carried out at a temperature and pressure that prevent high levels of deposit formation and catalyst fouling, i.e., operating conditions of moderate severity result in lower conversion of the heavy feedstock.

The first hydroconversion stage is advantageously carried out at a temperature ranging from 300 ℃ to 550 ℃, preferably from 350 ℃ to 500 ℃, and preferably from 370 ℃ to 440 ℃, and more preferably from 380 ℃ to 440 ℃. The absolute operating pressure may be from 2MPa to 35MPa, preferably from 5MPa to 25MPa, and preferably from 6MPa to 20 MPa. The amount of hydrogen mixed with the feedstock is preferably from 50 to 5000 standard cubic meters (Sm) obtained under standard temperature and pressure conditions (typically 15 ℃ and 1atm, i.e. 0.101325MPa)³) Per cubic meter (m)³) Liquid feedstock, preferably 100Sm³/m³-2000Sm³/m³And very preferably 200Sm³/m³-1000Sm³/m³。

According to the invention, of the first hydroconversion stageLiquid Hourly Space Velocity (LHSV) of 0.05h^-1-0.09h^-1The liquid hourly space velocity is the ratio of the flow rate of the liquid feedstock of the hydroconversion step a) obtained at standard temperature and pressure conditions (typically 15 ℃ and 1atm, i.e. 0.101325MPa) with respect to the total volume of the reactor or reactors employed in step a). The liquid hourly space velocity can be 0.05h^-1-0.08h^-1。

These temperature conditions associated with high residence times (relatively low LHSV) can simultaneously increase the overall conversion level of the process (i.e. the level of conversion of the initial feedstock 10 reached at the end of the process comprising two hydroconversion stages) and (by better compatibility, in particular of the first hydroconversion effluent 12 with the second hydroconversion effluent 18) the stability of the mixture with the second hydroconversion effluent 18 resulting from the second hydroconversion stage b), which is sent to the shared fractionation step d). Surprisingly, it has been demonstrated that combining a long residence time (relatively low LHSV) with a lower temperature can prevent the generation of new deposits during the mixing of the two

hydroconversion effluents

12 and 18.

In particular, the two hydroconversion effluents, which are a mixture, do not produce deposits in the separation system (C) in the fractionation step d). The mixture of hydroconversion effluents (12, 18) has, for example, a sediment content lower than that of said first hydroconversion effluent 12.

This is because, without being bound to a particular theory, the inventors have demonstrated that when high conversion in the first hydroconversion stage is obtained by long residence times (specific LHSV ranges), the effluent contains not only low levels of sediment, but also low levels of asphaltenes. Thus, surprisingly, the mixing of the first and second effluents does not produce additional deposits and may even produce lower than expected deposit contents. By virtue of the long residence times used according to the invention, the very high conversion of asphaltenes in the first hydroconversion stage makes it possible to avoid the incompatibility between the two effluents identified in the processes of the prior art. When the conversion of the first hydroconversion stage is moderate, problems appear to arise relating to the mixing of the hydroconversion effluent, which results in an effluent containing not only a relatively high content of deposits, but also asphaltenes which are incompatible with the strongly hydrogenated effluent. For this reason, the mixing of the first and second effluents appears to cause a drastic increase in the content of deposits in the overall liquid, which leads to very severe fouling of the items of equipment of the separation section (separators, distillation columns, heat exchangers, etc.) and which for this reason may require regular shutdowns for cleaning.

The conversion of the heavy hydrocarbon feedstock 10 in the first hydroconversion stage may be in the range of from about 30 wt% to about 95 wt%. The conversion may in particular be from about 30% to 75% by weight, indeed even from about 45% to about 55% by weight. According to certain embodiments, it may be less than 45 wt%.

In addition to the hydroconversion of the residuum 10, the removal of sulfur and metals may range from about 40% to about 75%, and the removal of conradson carbon may range from about 30% to about 60%. These degrees of removal are relative to the respective first hydroconversion stage A₁The flow rates of sulfur, metal and conradson carbon. These flow rates are derived from the flow rate of the feedstock and the content of sulfur, metals and conradson carbon originally present in the feedstock.

Suitable hydroconversion catalysts for the first hydroconversion stage, which may also be catalysts for hydroprocessing reactions, preferably comprise one or more elements from groups 4 to 12 of the periodic table of elements.

The hydroconversion catalyst used in the first hydroconversion step a) may comprise, consist of, or consist essentially of one or more elements selected from nickel, cobalt, tungsten and molybdenum, supported on a porous substrate (e.g. silica, alumina, titania or a combination thereof).

The content of nickel or cobalt, in particular nickel, expressed in weight of metal oxide (in particular NiO), is advantageously between 0.5% and 10% by weight, and preferably between 1% and 6% by weight, and in metal oxide (in particular molybdenum trioxide, MoO)₃) The content of molybdenum or tungsten, in particular molybdenum, expressed by weight of (A) is advantageously between 1% and 30% by weight and preferably 4% by weight-20% by weight. The metal content is expressed as a weight percentage of metal oxide relative to the weight of the catalyst.

The hydroconversion catalyst used in this first hydroconversion step is advantageously in the form of extrudates or beads. The beads have a diameter of, for example, 0.4mm to 4.0 mm. The extrudate has, for example, a cylindrical shape with a diameter of 0.5mm to 4.0mm and a length of 1mm to 5 mm. The extrudate may also be an object having a different shape, such as a regular or irregular trilobal, quadralobal or other polylobal shape. Other forms of catalyst may also be used.

The size of these various forms of catalyst can be characterized by the equivalent diameter. The equivalent diameter is defined as six times the ratio of the volume of the particle to the external surface area of the particle. The hydroconversion catalyst used in the form of extrudates, beads or other forms may thus have an equivalent diameter of from 0.4mm to 4.4 mm.

These catalysts are well known to those skilled in the art. Whether they are provided by the manufacturer or they result from the regeneration process of the used catalyst, they are preferably in the form of metal oxides. If desired, the catalyst in the form of one or more metal oxides may be converted to a metal sulfide prior to or during its use.

The hydroconversion catalyst may be presulfided and/or preconditioned prior to introduction into the hydroconversion reactor.

First hydroconversion stage A₁May include one or more reactors that may be placed in series and/or parallel. Suitable reactors for this first hydroconversion step may be any type of hydroconversion reactor, which is a three-phase reactor, i.e. operating in three phases, liquid, solid and gas. Due to the treatment of the asphaltenes of the heavy hydrocarbon feedstock during this first hydroconversion step, a reactor of the fluidized bed type or of the ebullating bed type with an upward liquid stream and a gaseous stream is preferred, i.e. it is a specific fluidized bed in the reactor in which the catalyst is kept boiling. Ebullated bed processes are described, for example, in patent US 4521295, patent US 4495060, patent US 4457831 and patent US 4354852, and in É ditin chapter 3.5 "Hydroprocessing and Hydroconversion of resource Fractions", the article technology, published in 2013, by the article "Catalysis by Transition Metal sulfides".

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

Sending the effluent resulting from step a) to a common separation system C and fractionating-step C) and step d)

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

The hydrocarbon residue fraction 14 comprises a portion of the residue 10 sent to the first hydroconversion step, which is unreacted, unconverted asphaltenes, and any hydrocarbon fraction boiling in the same range as the residue and resulting from the hydroconversion of the asphaltenes contained in the residue 10 sent to step a).

The recovered one or more hydrocarbon distillate fractions 13 may include, inter alia, gaseous fractions and atmospheric distillates, such as hydrocarbon compounds having boiling points below about 350 ℃, as well as vacuum distillates, such as hydrocarbon compounds having boiling points between about 300 ℃ and about 580 ℃.

Fractionation of the first and second hydroconversion effluents (12, 18) in a first hydroconversion stage A₁And a second hydroconversion stage A₂In a common separation system C.

As shown in fig. 1, the first hydroconversion effluent 12 and the second hydroconversion effluent 18 may be mixed prior to their introduction into the separation system C.

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

Solvent deasphalting-step e)

At least a portion of the hydrocarbon residue fraction 14 resulting from the fractionation step D) is sent to a solvent deasphalting unit D to recover a DAO (deasphalted oil) fraction 15 and an asphalt fraction 16. The DAO fraction 15 is almost free of asphaltenes and the asphaltic fraction 16 is concentrated in most of the impurities of the residue including asphaltenes.

Solvent Deasphalting unit D can be described, for example, as in one or more of US patent US 4239616, US patent 4440633, US patent 4354922, US patent 4354928, US patent 4536283, US patent 4715946 and US patent 7214308, and in "Heavy crop Oils: From genetics to Upgrading, An Overview" chapter 15 "Deasphalting with technological solutions" published by É conditions technology in 2011. Deasphalting is generally carried out at an average temperature of from 60 ℃ to 250 ℃ using at least one light hydrocarbon solvent (C)₃-C₇) Having 3 to 7 carbon atoms and may include propane, butane, isobutane, pentane, isopentane, hexane, isohexane, heptane, isoheptane, and mixtures thereof, optionally with the addition of at least one additive. Solvents and additives that can be used 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/feedstock ratio (v/v) in deasphalting is generally from 4/1 to 9/1, often from 4/1 to 8/1.

The deasphalting unit D produces DAO almost free of asphaltenes and residual bitumen in which most of the impurities of the residual oil are concentrated, said residual bitumen being discharged.

The DAO yield is generally from 40% to 90% by weight, depending on the quality of the heavy liquid fraction transported, the operating conditions and the solvent used. The DAO obtained advantageously appears as C₇An asphaltene content of less than 1% by weight, preferably less than 0.5% by weight, preferably less than 0.05% by weight, measured as insolubles, and as C₅Insoluble content (according to description C)₅Measured according to ASTM D893 standard for the determination of asphaltenes) and even more preferably an asphaltene content of less than 0.3% by weight, and as C₇An asphaltene content of less than 0.05 wt% as measured by insolubles.

In solvent deasphalting unitIn D, a light hydrocarbon solvent may be used to selectively dissolve the desired components of the hydrocarbon residue fraction and remove asphaltenes. According to one or more embodiments, the light hydrocarbon solvent may be a hydrocarbon solvent (C) having 3 to 7 carbon atoms₃-C₇) And may include propane, butane, isobutane, pentane, isopentane, hexane, isohexane, heptane, isoheptane, and mixtures thereof.

A second hydroconversion stage: hydroconversion of DAO-step b)

The DAO fraction 15 resulting from step e) is sent to a second hydroconversion stage A₂To undergo hydroconversion and form a reaction product referred to herein as a second hydroconversion effluent 18. Thus, it is possible to carry out the second hydroconversion stage A₂The DAO fraction 15 is reacted with hydrogen 17 over a hydroconversion catalyst to convert at least a portion of the hydrocarbon compounds present in the DAO to lighter molecules.

The second hydroconversion effluent 18 is then sent to a common separation system C during the fractionation step d) to be separated together with the first hydroconversion effluent 12 produced by the first hydroconversion step a) to recover the hydrocarbon compounds produced during the first and second hydroconversion steps and boiling in the distillate range, as described above in steps C) and d).

The hydroconversion catalyst of the second hydroconversion step b) may be the same as or different from the hydroconversion catalyst of the first hydroconversion step a).

Suitable catalysts for this second hydroconversion step b) are as described for the first hydroconversion step a).

Second hydroconversion stage A₂May include one or more reactors that may be placed in series and/or parallel.

Suitable reactors for this second hydroconversion step may be any type of three-phase hydroconversion reactor, in particular three-phase reactors of the entrained bed type, of the moving bed type, of the fluidized bed type, of the ebullating bed type or of the fixed bed type, with an upward liquid stream and a gaseous stream.

Asphaltenes may be present in the DAO to only a minor extent, which allows a wider range of types of reactor to be used in the second hydroconversion step.

For example, a fixed bed reactor may be used when the metal content and the conradson carbon content of the DAO fraction fed to the second hydroconversion step are less than 100 ppm by weight and 10% by weight, respectively.

The number of reactors required may depend on the flow rate of the feed feedstock (i.e., DAO fraction), the target overall conversion level of the residuum, and the conversion level achieved in the first hydroconversion step.

The temperature and pressure ranges of this second hydroconversion step b) are those as 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, thus avoiding too high a catalyst replacement rate. Thus, the overall replacement of catalyst (that is, for the two hydroconversion steps combined) is also reduced.

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

According to one or more alternative embodiments, the first hydroconversion stage A₁Is higher than in the second hydroconversion stage A₂The application of (1).

The Liquid Hourly Space Velocity (LHSV) of the second hydroconversion step may be 0.1h^-1-5.0h^-1Preferably 0.2h^-1-2.0h^-1The liquid hourly space velocity is the ratio of the flow rate of the liquid feedstock of the hydroconversion step b) taken at standard temperature and standard pressure conditions (typically 15 ℃ and 1atm, i.e. 0.101325MPa) with respect to the total volume of the reactor or reactors employed 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 fouling risk, the overall conversion of the residue in the process (i.e. the conversion at the end of the two hydroconversion stages) is high and can be higher than 80% by weight, in particular due to the partial conversion of asphaltenes in the first hydroconversion step and the hydroconversion of the DAO fraction during the second hydroconversion step b). With the process according to the invention it is possible to achieve an overall conversion of the residual oil of at least 80% by weight, indeed even at least 85% by weight, and even at least 90% by weight or more, while reducing the problems of instability and deposit formation that can occur during the mixing and sending to the fractionation of the hydroconversion effluents resulting from the two hydroconversion steps, which represent a significant advantage in terms of reliability, operability and simplified maintenance and related economic gains.

The process according to the invention therefore comprises a first hydroconversion stage A₁Downstream of a solvent deasphalting unit D in the first hydroconversion stage A₁In which the residence time of the treated residue is optimized, so that it can convert at least part of the asphaltenes into lighter and upgradable hydrocarbon compounds, while minimizing the risk of deposit formation during mixing with the DAO hydroconverted in the second hydroconversion step. The hydroconversion of asphaltenes in the first hydroconversion step a) can achieve an overall conversion of the residual oil of greater than about 60% by weight, indeed even greater than 85% by weight, and advantageously greater than 90% by weight, indeed even greater than 95% by weight, while minimizing the risk of fouling in the common separation unit (C) receiving the hydroconversion effluent. Furthermore, the size required for the solvent deasphalting unit employed in the process according to the invention can be smaller than that required when all the starting residue is treated, due to the conversion of at least a portion of the asphaltenes upstream (deasphalted).

Figure 2 illustrates an example of a method according to the invention. As described in connection with fig. 1, the first hydroconversion effluent 12 resulting from the first hydroconversion step a) and the second hydroconversion effluent resulting from the second hydroconversion step b) are fed18 to a separation system C. According to this example, the separation system C comprises at least one high-pressure high-temperature separator C₁("HP/HT" separator or "HHPS", for "Hot high pressure separator"), atmospheric distillation column C₂And a vacuum distillation column C₃. The separation system C may also include a cooling, purification and gas compression system R. Other separators (not shown) may form part of the separation system C, such as, for example, a medium-pressure high-temperature separator ("MP/HT" separator or "HMPS", for "hot medium-pressure separator") downstream of the HP/HT separator and upstream of the distillation column, a high-pressure medium-temperature separator ("HP/MT" separator or "WHPS", for "medium-temperature high-pressure separator") and a high-pressure low-temperature separator ("HP/LT" separator or "CHPS", for "cold high-pressure separator") on the gas circuit, a medium-pressure low-temperature separator ("MP/LT" separator or "CMPS", for "cold medium-pressure separator") on the outlet line of the condensed hydrocarbons 22 downstream of R.

HP/HT separator C₁The effluent of the hydroconversion can be separated into a gas phase product 19 and a liquid phase product 20.

The gas phase product 19 may be directed to a cooling, purification and gas compression system R. Thus, a hydrogen-containing gas 21 can be recovered from the system, a portion of which can be recycled to the first hydroconversion stage A₁And a second hydroconversion stage A₂The reactor of (1). The hydrocarbons 22 condensed during cooling and purification can be recovered and combined with the liquid phase product 20 for subsequent processing. The combined liquid stream 23 can then be introduced into an atmospheric distillation column C₂To separate the stream into a first light fraction 24 comprising hydrocarbon compounds boiling in the atmospheric distillate range and a first heavy fraction 25 comprising hydrocarbon compounds boiling at least 300 ℃. As illustrated, the first light fraction 24 and the first heavy fraction 25 may be recovered through different lines.

The first heavy fraction 25 may then be introduced into a vacuum distillation system C₃To separate the first bottoms fraction 25 into a second light fraction 26 comprising hydrocarbon compounds boiling in the vacuum distillate range and a second heavy fraction 14 comprising hydrocarbon compounds boiling at least 450 ℃. As illustrated, may be passed throughThe same line recovers the second light fraction 26 and the second heavy fraction 14. The second heavy fraction 14 is sent to a solvent deasphalting unit D.

It may be desirable to reduce the temperature of the second heavy fraction 14 prior to feeding to the solvent deasphalting unit D. The second heavy fraction 14 may thus be cooled by heat exchange. Due to the greater risk of fouling of the indirect heat exchange system, direct heat exchange is preferred and may be performed, for example, by contacting the second heavy fraction 14 with at least a portion 28 of the first heavy fraction 25 and/or a portion 27 of the residuum 10.

As shown in fig. 2, the method according to the invention may comprise a dedicated cooling, purification and gas compression system R. According to other embodiments, in HP/HT separator C₁Or at least a portion of the latter, can be processed in a common cooling, purification and gas compression system, which incorporates the treatment of the gases originating from other hydrofinishing units on site.

Although this is not shown, according to certain embodiments, at least a portion of pitch 16 may be recycled to first hydroconversion reactor stage a₁. Upgrading or use of bitumen 16 may be performed using other methods known to those skilled in the art. For example, pitch 16 may be mixed with LCO or HCO fractions or resids ("slurry oils") produced from an FCC unit for use as a fuel, or processed, or converted into pitch particles, either alone or in combination with other feedstocks in a delayed coking or gasification unit.

Examples

The following examples illustrate embodiments of the method according to the invention (without limiting its scope) and some of its performance qualities compared to the method according to the prior art.

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

Raw materials

The heavy hydrocarbon feedstock is a straight run Vacuum Residue (VR) derived from Urals crude oil, the main characteristics of which are listed in table 1 below.

For the different examples, the VR heavy feed was the same fresh feed.

Example 1: according to prior art methods (not according to the invention)

This example illustrates a process for hydroconversion of a heavy hydrocarbon feedstock comprising two hydroconversion stages, each comprising a reactor functioning as an ebullating bed and at a conventional liquid hourly space velocity (0.1 h), according to the prior art^-1-5h^-1) The operation is carried out.

First hydroconversion stage

The fresh feedstocks of Table 1 are fed in their entirety to the first hydroconversion stage A in the presence of hydrogen₁The stage comprises two three-phase reactors R1 and R2 containing a NiMo/alumina hydroconversion catalyst exhibiting a NiO content of 4 wt% and MoO₃The content is 10% by weight, percentages being expressed relative to the total weight of the catalyst. Both reactors operate as ebullated beds operating with liquid and gas flow upward.

The operating conditions employed in the first hydroconversion stage are listed in table 2 below.

These operating conditions allow to obtain a catalyst with reduced C₇A liquid hydroconversion effluent having an asphaltene content, a Conradson carbon content, a nitrogen content, and a sulfur content. The yield structure and overall performance quality at the outlet of the first stage are given in table 3 together with the composition of the overall liquid and the sediment content of the atmospheric residue. The conversion of the 540 c + fraction at the outlet of the first hydroconversion stage was 55 wt%. The atmospheric resid sent to the separation system contained 0.19 wt.% deposits.

Second hydroconversion stage

The DAO fraction originating from the deasphalter, the properties of which are given in Table 4, is sent in its entirety to the second hydroconversion stage A in the presence of hydrogen₂The stage comprises two three-phase reactors R3 and R4 containing a NiMo/alumina hydroconversion catalyst exhibiting a NiO content of 4 wt% and MoO₃The content is 10% by weight, percentages being expressed relative to the total weight of the catalyst. The reactor operates as an ebullated bed operating with upward liquid and gas flow.

The operating conditions employed in the second hydroconversion stage are listed in table 5 below.

These operating conditions allow to obtain a catalyst with reduced C₇A liquid hydroconversion effluent having an asphaltene content, a Conradson carbon content, a nitrogen content, and a sulfur content. The yield structure and overall performance quality at the outlet of the second stage are given in table 6 together with the composition of the overall liquid and the sediment content of the atmospheric residue. The conversion of the 540 c + fraction at the outlet of the second hydroconversion stage was 78 wt%. The atmospheric resid sent to the separation system is free of deposits.

Mixture of the first and second effluents

The reaction products resulting from the first hydroconversion stage a), i.e. the first hydroconversion effluent and the reaction products resulting from the second hydroconversion stage b), are sent to a common separation system C to be subjected to fractionation. The normalized yield structure and the composition of the liquid entering the separation system are given in table 7.

It is noteworthy that the content of deposits is greatly increased. This is because the overall liquid sediment content in the atmospheric residue from the first hydroconversion stage is 0.19 wt% and below the detection limit in the atmospheric residue from the second hydroconversion stage. Due to the incompatibility of the two effluents, their mixture contained 0.50% by weight of deposits in the atmospheric residue, i.e. an increase of 150%. This leads to very severe fouling of the equipment items of the separation section (separators, distillation columns, heat exchangers, etc.).

Deasphalting

The vacuum residue leaving 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.

The yields of deasphalted oil ("DAO" fraction) and bitumen are given in table 9, while the composition of DAO is given in table 4.

In this case, the DAO fraction is sent in its entirety to the inlet of the second hydroconversion stage.

Overall conversion of the scheme

Using this configuration not in accordance with the present invention, the protocol can convert about 79% of the 540℃ + fraction as shown in table 10.

On the other hand, the very high sediment content at the inlet of the separation section leads to very severe fouling of the equipment items of this section (separators, distillation columns, heat exchangers, etc.) and for this reason regular shutdowns for cleaning are required.

Example 2: method according to the invention (according to the invention)

This example illustrates a process for the hydroconversion according to the invention of a heavy hydrocarbon feedstock comprising two hydroconversion stages, each comprising a reactor functioning as an ebullating bed and operating at a liquid hourly space velocity according to the invention (less than 0.1h for the first hydroconversion stage)^-1)。

First hydroconversion stage

The fresh feedstocks of Table 1 are fed in their entirety to the first hydroconversion stage A in the presence of hydrogen_1，The stage included two three-phase reactors R1 and R2 containing a NiMo/alumina hydroconversion catalyst exhibiting a NiO content of 4 wt% and MoO₃The content is 10% by weight, percentages being expressed relative to the total weight of the catalyst. Both reactors operate as ebullated beds operating with liquid and gas flow upward.

The operating conditions employed in the first hydroconversion stage are listed in table 11 below.

These operating conditions allow to obtain a catalyst with reduced C₇A liquid hydroconversion effluent having an asphaltene content, a Conradson carbon content, a nitrogen content, and a sulfur content. The yield structure and overall performance quality at the outlet of the first stage are given in table 12 together with the composition of the overall liquid and the sediment content of the atmospheric residue. The conversion of the 540 c + fraction at the outlet of the first hydroconversion stage was 83 wt%. The atmospheric resid sent to the separation system contained 0.04 wt.% deposits.

Second hydroconversion stage

The DAO fraction originating from the deasphalter, the properties of which are given in Table 13, is sent in its entirety to the second hydroconversion stage A in the presence of hydrogen₂The stage comprises two three-phase reactors R3 and R4 containing a NiMo/alumina hydroconversion catalyst exhibiting a NiO content of 4 wt% and MoO₃The content is 10% by weight, percentages being expressed relative to the total weight of the catalyst. The reactor operates as an ebullated bed operating with upward liquid and gas flow.

The operating conditions employed in the second hydroconversion stage are given in table 14 below.

These operating conditions allow to obtain a catalyst with reduced C₇A liquid hydroconversion effluent having an asphaltene content, a Conradson carbon content, a nitrogen content, and a sulfur content. The yield structure and overall performance quality at the outlet of the second stage are given in table 15 together with the composition of the overall liquid and the sediment content of the atmospheric residue. The conversion of the 540 c + fraction at the outlet of the second hydroconversion stage was 79 wt%. The atmospheric resid sent to the separation system is free of deposits.

Mixture of the first and second effluents

The reaction products resulting from the first hydroconversion stage a), i.e. the first hydroconversion effluent and the reaction products resulting from the second hydroconversion stage b), are sent to a common separation system C to be subjected to fractionation. The normalized yield structure and the composition of the liquid entering the separation system are given in table 16.

Notably, the sediment content is reduced due to the dilution effect. This is because the sediment content in the atmospheric residue from the first hydroconversion stage is 0.16 wt% and below the detection limit in the atmospheric residue from the second hydroconversion stage. The very high conversion of asphaltenes in the first hydroconversion stage can avoid incompatibility between the two effluents. Thus, their mixture contained 0.14 wt% of sediment in the atmospheric residue, i.e., a sediment content lower than that of the atmospheric residue from the first reactor.

Deasphalting

The vacuum residue leaving 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.

The yields of deasphalted oil ("DAO" fraction) and bitumen are given in Table 18, while the composition of the DAO is given in Table 13.

Overall conversion of the scheme

With this configuration according to the invention, the protocol can convert more than 93% of the 540 ℃ + fraction, as shown in table 19.

Furthermore, the very low sediment content at the inlet of the separation section greatly improves the operability of the section by greatly reducing the fouling of the equipment items.

Claims

1. Process for converting a heavy hydrocarbon feedstock containing a fraction at least 50% of which have a boiling point of at least 300 ℃, comprising the steps of:

a) in the first hydroconversion stage (A)₁) Hydroconverting the heavy hydrocarbon feedstock (10) to form a first effluent (12);

b) in the second hydroconversion stage (A)₂) Hydroconverting the deasphalted oil fraction (15) to form a second effluent (18);

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

d) fractionating the first and second effluents as a mixture in the separation system (C) to form at least one hydrocarbon distillate fraction (13) and one hydrocarbon residue fraction (14);

e) sending at least a portion of the hydrocarbon residue fraction (14) to a solvent deasphalting unit (D) to obtain a deasphalted oil fraction (15) and an asphalt fraction (16),

wherein the liquid hourly space velocity of step a) is 0.05h^-1-0.09h^-1。

2. The process according to claim 1, wherein the liquid hourly space velocity employed in step a) is 0.05h^-1-0.08h^-1。

3. The process according to any of the preceding claims, wherein the second hydroconversion stage (A) in step b) is₂) At least one of the operating temperature and the operating pressure in (a) is greater than in the first hydroconversion stage (A) in step a)₁) The operating temperature and the operating pressure in (1).

4. The method according to any one of claim 1 and claim 2,wherein the second hydroconversion stage (A) in step b)₂) At least one of the operating temperature and the operating pressure in (a) is less than that in the first hydroconversion stage (A) in step a)₁) The operating temperature and the operating pressure in (1).

5. The process according to any of the preceding claims, wherein the liquid hourly space velocity employed in step b) is 0.1h^-1-5.0h^-1。

6. The process according to any one of the preceding claims, wherein the first hydroconversion stage (A) in step a) is₁) At least a portion of the asphaltenes contained in the heavy hydrocarbon feedstock are converted.

7. The process according to any of the preceding claims, wherein the first hydroconversion stage (A) in hydroconversion step a) is₁) At a temperature and pressure such that the heavy hydrocarbon feedstock is converted to a degree of conversion of from about 30 wt.% to about 95 wt.% of the heavy hydrocarbon feedstock (10).

8. The process according to claim 7, wherein the overall conversion of the heavy hydrocarbon feedstock (10) at the end of the process is at least 60 wt% of the heavy hydrocarbon feedstock (10), preferably at least 90 wt% of the heavy hydrocarbon feedstock (10).

9. The process according to any one of the preceding claims, wherein the hydrocarbon residue fraction (14) resulting from step d) comprises hydrocarbon compounds having a boiling point of at least 300 ℃.

10. The process according to any one of the preceding claims, wherein the first hydroconversion stage (A)₁) Including a single ebullated bed reactor.

11. The process according to any one of the preceding claims, wherein the second hydroconversion stage (A)₂) Involving at least one ebullated bed reactionAnd/or a fixed bed reactor.

12. The process of any of the preceding claims, wherein fractionating step d) comprises:

at high pressure and high temperature in a separator (C)₁) Separating the first and second effluents (12, 18) to obtain a gas-phase product (19) and a liquid-phase product (20);

in an atmospheric distillation column (C)₂) Separating the liquid phase product (20) to recover a first light fraction (24) comprising hydrocarbon compounds boiling in the atmospheric distillate range and a first heavy fraction (25) comprising hydrocarbon compounds boiling at least 300 ℃;

in a vacuum distillation column (C)₃) Separating the heavy fraction (25) to recover a second light fraction (26) comprising hydrocarbon compounds boiling in the vacuum distillate range and a second heavy fraction (14) comprising hydrocarbon compounds boiling at least 450 ℃; and

-sending the second heavy fraction (14) as a hydrocarbon residue fraction to the solvent deasphalting unit (D) in step e),

wherein step a) of hydroconverting the heavy hydrocarbon feedstock comprises:

-sending hydrogen (11) and the heavy hydrocarbon feedstock (10) to a first hydroconversion reactor containing a first hydrocracking catalyst;

-contacting said heavy hydrocarbon feedstock (10) with hydrogen (11) in the presence of a first hydrocracking catalyst under temperature and pressure conditions that allow at least a portion of said heavy hydrocarbon feedstock to undergo conversion;

-recovering a first effluent (12) from the first hydroconversion reactor;

and wherein step b) of hydroconverting 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;

-contacting the deasphalted oil fraction (15) with hydrogen (17) in the presence of a second hydrocracking catalyst under temperature and pressure conditions allowing the conversion of at least part of the deasphalted oil; and

-recovering a second effluent (18) produced from the second hydroconversion reactor.

13. The method according to claim 12, further comprising cooling the gas phase product (19) to recover a gas fraction (21) containing hydrogen and a distillate fraction (22), and sending the distillate fraction (22) to the atmospheric distillation column (C)₂)。

14. The method of claim 13, further comprising recycling at least a portion of the hydrogen-containing gas fraction (21) in at least one of the first and second hydroconversion reactors.

15. The process according to any of claims 12-14, further comprising cooling the second heavy fraction (14) via direct heat exchange with at least one of the portion of the residuum (10) and the portion (28) of the first heavy fraction (25).

16. The process according to any one of the preceding claims, wherein the hydrocarbon residue fraction (14) comprises hydrocarbon compounds having a boiling point of at least 450 ℃.

17. The process according to any one of the preceding claims, wherein hydroconversion step a) is at an absolute pressure of from 2 to 35MPa, at a temperature of from 300 ℃ to 550 ℃ and at from 50 to 5000Sm³/m³The amount of hydrogen with which the heavy hydrocarbon feedstock is mixed.

18. The process according to any of the preceding claims, wherein the first effluent (12) and the second effluent (18) as a mixture in the separation system (C) in the fractionation step d) do not produce additional deposits.

19. The process according to any one of the preceding claims, wherein the heavy hydrocarbon feedstock (10) contains a fraction, and preferably is crude oil, or consists of atmospheric and/or vacuum residue resulting from atmospheric and/or vacuum distillation of crude oil, and preferably consists of vacuum residue resulting from vacuum distillation of crude oil, at least 80% of the fraction having a boiling point of at least 300 ℃.

20. The process according to any of the preceding claims, wherein the heavy hydrocarbon feedstock has a sulfur content of at least 0.1 wt.%, a Conradson carbon content of at least 0.5 wt.%, a C of at least 1 wt.%₇An asphaltene content and a metal content of at least 20 ppm by weight.