阅读说明：本技术 包括固定床加氢处理、脱沥青操作和沥青的沸腾床加氢裂化的处理重质烃基原料的方法 (Process for treating heavy hydrocarbon-based feedstocks including fixed bed hydroprocessing, deasphalting operations and ebullated bed hydrocracking of pitch ) 是由 W.维斯 I.梅尔德里尼亚克 于 2019-07-24 设计创作，主要内容包括：本发明涉及包含一系列具体步骤的制造燃料原料的方法,包括固定床加氢裂化步骤、来自固定床加氢裂化步骤的重质馏分的脱沥青步骤、DAO馏分的固定床加氢裂化步骤、以及该沥青馏分的沸腾床加氢裂化步骤。(The present invention relates to a process for the manufacture of a fuel feedstock comprising a series of specific steps, including a fixed bed hydrocracking step, a deasphalting step of the heavy fraction coming from the fixed bed hydrocracking step, a fixed bed hydrocracking step of the DAO fraction, and an ebullated bed hydrocracking step of the bituminous fraction.)

1. A process for treating a hydrocarbon-based feedstock having a sulfur content of at least 0.1 wt.%, an initial boiling point of at least 340 ℃ and a final boiling point of at least 600 ℃, the process comprising the steps of:

a) a hydrotreating step carried out in a fixed bed reactor in which a hydrocarbon-based feedstock is contacted with a hydrotreating catalyst in the presence of hydrogen,

b) a step of separating the effluent from the hydrotreatment step a) into at least one light fraction and a heavy fraction containing compounds boiling at least 350 ℃,

c) a step of deasphalting the heavy fraction coming from the separation step b) by means of a solvent or a mixture of solvents, which allows on the one hand to obtain a fraction comprising the asphalt and the solvent or mixture of solvents, and on the other hand to obtain a fraction comprising the deasphalted oil,

d) a step of hydrocracking at least a portion of the fraction comprising deasphalted oil coming from step c), in at least one fixed bed reactor in the presence of a hydrocracking catalyst and hydrogen,

e) an optional step of separating the effluent from step d) into at least one gaseous fraction and a heavy liquid fraction containing compounds boiling at least 350 ℃,

f) a step of hydrocracking at least a portion of the fraction comprising bitumen from step c) in the presence of a hydrocracking catalyst and hydrogen in at least one ebullated-bed reactor,

g) a step of separating the effluent from step f) into at least one gaseous fraction and a heavy liquid fraction containing compounds boiling at least 350 ℃,

h) a step of precipitating a sediment of the heavy liquid fraction from step g):

-contacting said heavy liquid fraction with an oxidizing agent at a temperature of from 25 to 350 ℃ and a pressure of less than 20 MPa for a time of less than 500 minutes,

-or by contacting said heavy liquid fraction with a distillation fraction at a temperature of from 25 to 350 ℃ and a pressure of less than 20 MPa for a time of less than 500 minutes, at least 20% by weight of said distillation fraction having a boiling point of greater than or equal to 100 ℃,

i) a step of physical separation of the sediment from the heavy liquid fraction coming from the precipitation step h), whereby on the one hand a liquid hydrocarbon-based fraction with a low sediment content is obtained, optionally as a mixture with a distillation fraction or with an oxidizing agent, and on the other hand a sediment fraction is obtained.

2. The process according to claim 1, wherein a portion of the heavy fraction obtained in step g) is recycled to the deasphalting step c).

3. The process according to any one of the preceding claims, wherein a portion of the heavy fraction obtained in step g) is recycled to the ebullated bed hydrocracking step f).

4. The process according to any one of the preceding claims, comprising an optional step j) of separating the liquid hydrocarbon-based fraction with low sediment content coming from step i) from the distillation fraction introduced during the sediment precipitation step h).

5. The process of any one of the preceding claims, comprising an optional step j) of separating the oxidizing agent introduced during the sediment precipitation step h).

6. The process of any one of the preceding claims, wherein at least a portion of the heavy fraction comprising at least 80% of compounds boiling at 350 to 540 ℃ from separation step b) is sent to the hydrocracking step d).

7. The process of any one of the preceding claims, wherein at least a portion of the heavy fraction comprising at least 80% of the compounds boiling at 350 to 540 ℃ from separation step e) is sent back to the hydrocracking step d).

8. The process of any one of the preceding claims, wherein at least a portion of the heavy fraction comprising at least 80% of the compounds boiling at 350 to 540 ℃ from step g) of separating the effluent from hydrocracking step f) is sent to the hydrocracking step d).

9. The process according to any one of the preceding claims, wherein the solvent used in step c) is a non-polar solvent consisting of one or more saturated hydrocarbons comprising a carbon number greater than or equal to 3, preferably from 3 to 4.

10. The process of claim 9, wherein deasphalting step c) is carried out under subcritical conditions of said solvent.

11. The process of claim 9 or 10, wherein in step c) a portion of the solvent is injected into the extraction column at a first point and another portion of the solvent is injected into the extraction column at a second point, the second point being located below the first point.

12. The process according to any one of the preceding claims, wherein step c) is carried out at a deasphalting temperature of from 50 to 350 ℃ and a pressure of from 0.1 to 6.0 MPa.

13. The process according to any one of the preceding claims, wherein the hydrocarbon-based feedstock is selected from atmospheric residues, vacuum residues from straight run, crude oil, topped crude oil, oil sands or derivatives thereof, asphaltite or derivatives thereof, and source rock oil or derivatives thereof, taken alone or in admixture.

Technical Field

The present invention relates to the treatment of heavy hydrocarbon fractions containing inter alia sulphur-based impurities, metals and asphaltenes. It relates more particularly to a process for treating heavy petroleum feedstocks of the atmospheric and/or vacuum residuum type, to produce fuels or fuel feedstocks for transportation or energy production with reduced impurity content, and to produce distillates for petrochemistry and transportation, and whose yields can be adjusted thanks to the flexibility offered by the present invention.

General conditions

The fractions which can be used as bunker fuel or bunker fuel (e.g. bunker fuel oil or bunker fuel oil feedstock) must have a low impurity content, in particular a low sulphur content, and must meet the bunker fuel quality requirements described in standard ISO 8217.

The specification for sulfur now also relates to SOx emissions (appendix VI of the MARPOL convention of the International maritime organization) and results in a sulfur content recommendation of less than or equal to 0.5 wt.% outside the emission control zone (ECAs) and less than or equal to 0.1 wt.% within the emission control zone within the 2020 & 2025 timeframe.

In the field of processing heavy hydrocarbon fractions, hydrotreating and hydrocracking processes enable a reduction in the content of impurities, while enabling a more or less extensive conversion of the feedstock into lighter products.

These impurities may be metals, sulphur or sulphur oxides, nitrogen, conradson carbon. The heavy hydrocarbon fraction may also contain asphaltenes, in particular asphaltenes insoluble in heptane, also referred to as C ₇Asphaltenes. C ₇Asphaltenes are compounds known to inhibit the conversion of residual fractions (cut) by their ability to form heavy hydrocarbon residues, commonly known as coke, and by their tendency to produce deposits that greatly limit the operability of hydrotreating and hydroconversion units.

Another very restrictive suggestion in standard ISO 8217 is the content of deposits after ageing according to standard ISO 10307-2 (also known as IP 390), which must be less than or equal to 0.1%. This aged sediment content is far more limiting than the sediment content according to ISO 10307-1 (known as IP 375). In addition to the deposits present in the heavy fraction at the outlet of the process (measured according to ISO 10307-1, also known as IP 375), there are deposits described as potential deposits, depending on the conversion conditions. These deposits typically occur after physical, chemical and/or thermal treatment.

In processes for treating heavy hydrocarbon fragments, it is known practice to carry out deasphalting operations. Deasphalting allows to separate an asphaltene-rich fraction from a deasphalted oil fraction (known as DAO) with a greatly reduced asphaltene content, thus facilitating its exploitation by catalytic cracking or hydrocracking. For example, patent FR 2753983 describes a process for converting a heavy hydrocarbon fraction comprising a fixed bed hydrotreatment step followed by a deasphalting step of the vacuum residue obtained after atmospheric and vacuum distillation of the effluent obtained from this hydrotreatment, the DAO being subsequently sent to an ebullated bed hydrotreatment step. One problem encountered is the exploitation of the fraction of bitumen, which is generally regarded as waste; it is therefore advantageous to convert this fraction to other products of higher value or to limit the yield of bitumen. Patent US 7214308 describes a conversion process in which the residual feedstock is treated in a deasphalting step, the DAO fraction is subsequently sent to an ebullated bed hydrocracking step, and the asphaltic fraction is sent to another ebullated bed hydrocracking step. According to this embodiment, the yield of bitumen is high and the product from the ebullated bed hydrocracking step of bitumen is not very purified; exploitation, for example, in the low-sulfur content marine fuels of the heavy fraction is not possible.

The present invention aims to overcome the problems of the prior art described above and in particular to provide a process which allows the flexible production of fuel stocks, in particular bunker fuel or bunker fuel stocks, such as bunker fuel or bunker fuel stocks, having a low content of impurities, in particular sulphur, and meeting the bunker fuel quality requirements described in standard ISO 8217, as well as a reduction of the bituminous fraction and a better exploitation thereof, thereby increasing the cost-effectiveness of the process compared to known processes. The term "flexible production" is intended to mean a production in which the conversion (degree of conversion) and thus the ratio between light products and heavy products can be adjusted.

One aim of the process of the invention is to co-produce distillates that can be used in petrochemistry and in transportation, for example distillates of the naphtha, kerosene and/or diesel type.

Thus, the applicant has developed a new process for producing a fuel feedstock comprising a series of specific steps, including a fixed bed hydrotreatment step for reducing the impurities, in particular the asphaltene content, of the product obtained by the process, a step of deasphalting the heavy fraction obtained in the fixed bed hydrotreatment process to produce a DAO fraction and an asphalt fraction, a fixed bed hydrocracking step of the DAO fraction and an ebullated bed hydrocracking step of the asphalt fraction.

The invention has the following advantages:

flexibility in terms of yield of products from conversion of the initial heavy feedstock, which can be used as fuel, such as bunker fuel or bunker fuel feedstock, for example bunker fuel or bunker fuel feedstock, in particular by means of optional recycling of unconverted fraction from the ebullated bed hydrocracking step upstream of this step or upstream of deasphalting;

a step of precipitation and separation of the sediment of the heavy fraction coming from the ebullated bed hydrocracking step of the bituminous fraction, which makes it possible to obtain a fuel feedstock with a low sediment content, in particular a marine fuel feedstock.

Summary of The Invention

The subject of the present invention is thus a process for treating a hydrocarbon-based feedstock having a sulphur content of at least 0.1% by weight, an initial boiling point of at least 340 ℃ and a final boiling point of at least 600 ℃, said process comprising the steps of:

a) a hydrotreating step carried out in a fixed bed reactor in which a hydrocarbon-based feedstock is contacted with a hydrotreating catalyst in the presence of hydrogen,

b) a step of separating the effluent from the hydrotreatment step a) into at least one light fraction and a heavy fraction containing compounds boiling at least 350 ℃,

c) a step of deasphalting the heavy fraction coming from the separation step b) by means of a solvent or a mixture of solvents, which allows on the one hand to obtain a fraction comprising the asphalt and the solvent or mixture of solvents, and on the other hand to obtain a fraction comprising the deasphalted oil,

d) a step of hydrocracking at least a portion of the fraction comprising deasphalted oil coming from step c), in at least one fixed bed reactor in the presence of a hydrocracking catalyst and hydrogen,

e) an optional step of separating the effluent from step d) into at least one gaseous fraction and a heavy liquid fraction containing compounds boiling at least 350 ℃,

f) a step of hydrocracking at least a portion of the fraction comprising bitumen from step c) in the presence of a hydrocracking catalyst and hydrogen in at least one ebullated-bed reactor,

g) a step of separating the effluent from step f) into at least one gaseous fraction and a heavy liquid fraction containing compounds boiling at least 350 ℃,

h) a step of precipitating a sediment of the heavy liquid fraction from step g):

-contacting said heavy liquid fraction with an oxidizing agent at a temperature of from 25 to 350 ℃ and a pressure of less than 20 MPa for a time of less than 500 minutes,

or by contacting said heavy liquid fraction with a distillation fraction, at least 20% by weight of which has a boiling point greater than or equal to 100 ℃, at a temperature of from 25 to 350 ℃ and a pressure of less than 20 MPa for a time of less than 500 minutes,

i) a step of physical separation of the sediment from the heavy liquid fraction coming from the precipitation step h), whereby on the one hand a liquid hydrocarbon-based fraction with a low sediment content is obtained, optionally as a mixture with a distillation fraction or with an oxidizing agent, and on the other hand a sediment fraction is obtained.

Advantageously, the sequence of the invention enables the asphaltene content to be reduced during the fixed bed hydrotreatment step and thus the amount of bitumen produced during the deasphalting process to be reduced. Furthermore, the fixed bed hydrotreating step enables a reduction in the sulphur content and therefore also in the products of the fixed bed hydrocracking step of DAO and of the products of the downstream steps of ebullated bed hydrocracking of the bituminous fraction.

Advantageously, the optional recycling of a portion of the unconverted heavy fraction upstream of deasphalting makes it possible to increase the yield of deasphalted oil DAO and thus the production of distillates in a fixed bed hydrocracking process.

Advantageously, the optional recycling of a portion of the unconverted heavy fraction upstream of the ebullated bed hydrocracking step of the bituminous fraction enables an increase in the production of lighter products.

Furthermore, a subject of the present invention is an optional step j) of separating said liquid hydrocarbon-based fraction with low sediment content coming from step i) from the distillation fraction or from the oxidant introduced during the sediment precipitation step h).

According to one embodiment, at least a portion of the heavy fraction obtained in separation step b) of the effluent from hydrotreatment step a) comprising at least 80% of compounds with a boiling point of 350 to 540 ℃ is sent to the hydrotreatment step d).

According to one embodiment, at least a portion of the heavy fraction comprising at least 80% of the compounds having a boiling point of between 350 and 540 ℃ obtained in the separation step e) of the effluent from hydrocracking step d) is sent back to the hydrocracking step d).

According to one embodiment, at least a portion of the heavy fraction obtained in the separation step g) of the effluent from hydrocracking step f), comprising at least 80% of compounds having a boiling point of between 350 and 540 ℃, is sent to hydrocracking step d).

According to one embodiment, the solvent used in step c) is a non-polar solvent consisting of one or more saturated hydrocarbons comprising a carbon number greater than or equal to 3, preferably from 3 to 4.

According to one embodiment, a portion of the solvent is injected into the extraction column at a first point, and another portion of the solvent is injected into the extraction column at a second point located below the first point.

According to one embodiment, the hydrocarbon-based feedstock is selected from atmospheric residues, vacuum residues obtained from direct distillation, crude oil (crude oil), topped crude oil (topped crude oil), oil sands (oil sand) or derivatives thereof, bituminous schists (bitumen schists) or derivatives thereof, and source rock oils (source rock oil) or derivatives thereof, taken alone or in a mixture.

According to one embodiment, the deasphalting step c) is carried out under subcritical conditions of said solvent.

According to one embodiment, step c) is carried out at a deasphalting temperature of between 50 and 350 ℃ and at a pressure of between 0.1 and 6 MPa.

Further subjects and advantages of the invention will become apparent from reading the description which follows of a particular exemplary embodiment of the invention, given as a non-limiting example, with reference to the following drawings.

Brief description of the drawings

FIG. 1 is a schematic illustration of a process according to an embodiment of the present invention.

Fig. 2 is a variation of the embodiment of the method of the invention shown in fig. 1.

Fig. 3 is a variation of the embodiment of the method of the present invention shown in fig. 1.

Detailed Description

It is stated that throughout this specification the expression "… … to … …" is to be understood as including the mentioned boundaries.

The various embodiments presented can be used alone or in combination with one another for the purposes of the present invention, without any limitation to this combination.

In the remainder of the description, reference is made to fig. 1, which describes an example of a process for treating a heavy hydrocarbon-based feedstock, implementing the invention. The information in the rest of the description about the elements referenced in fig. 1 enables a better understanding of the invention, which is not limited to the specific embodiment shown in fig. 1.

As shown in fig. 1, the method of the present invention comprises the steps of:

-a step a) of hydrotreating an initial hydrocarbon-based feedstock 1 in the presence of a hydrogen-rich gas 2 and optionally a co-feed 3, which is carried out in a fixed bed reactor comprising a hydrotreating catalyst;

a step b) of separating the effluent 4 from the hydrotreatment step a) which makes it possible to obtain at least a light fraction 5 and a heavy fraction 7 containing compounds boiling at least 350 ℃, and optionally a heavy fraction 6 comprising at least 80% of the compounds boiling at 350 to 540 ℃;

a step c) of deasphalting the heavy fraction 7 coming from the separation step b) as a mixture with a solvent or solvent combination 8, which makes it possible to obtain at least one fraction comprising deasphalted oil (DAO) 11 and solvent or solvent mixture, and a fraction 10 comprising bitumen and solvent or solvent mixture, optionally extracted by means of a fluxing agent (flux) 9;

step d) of hydrocracking DAO 11 in the presence of a hydrogen-rich gas 12 and optionally an auxiliary feedstock 13 and/or fraction 6 from step b) and/or fraction 18 from step e) and/or fraction 24 from step g), carried out in at least one fixed-bed reactor containing a hydrocracking catalyst;

a step e) of separating the effluent 14 from the hydrocracking step d), which is capable of obtaining at least one gaseous fraction 15 and a heavy liquid fraction 16 comprising at least 80% of the compounds boiling at 350 to 540 ℃; optionally, a portion of the fraction 16 may be sent to deasphalting step c) via line 17 and/or to fixed bed hydrocracking step d) via line 18;

-a step f) of hydrocracking the bitumen 10 in the presence of a hydrogen-rich gas 19 and optionally a co-feed 20 and/or a fraction 26 from step g), carried out in at least one ebullated-bed reactor containing a hydrocracking catalyst;

a step g) of separating the effluent 21 from hydrocracking step f), which makes it possible to obtain at least one gaseous fraction 22 and a heavy fraction 25 containing compounds boiling at least 350 ℃, and optionally a heavy fraction 23 comprising at least 80% of compounds boiling at 350 to 540 ℃; optionally, a portion of fraction 23 may be sent to fixed bed hydrocracking step d) via line 24 and/or a portion of fraction 25 may be sent to ebullated bed hydrocracking step f) via line 26 and/or to deasphalting step c) via line 27;

a stage h) of precipitating the sediment by contacting the heavy fraction 25 coming from stage g) with a distillation fraction 28, at least 20% by weight of which has a boiling point greater than or equal to 100 ℃, at a temperature of between 25 and 350 ℃ and a pressure of less than 20 MPa, for a period of less than 500 minutes, or by contacting with an oxidizing agent at a temperature of between 25 and 350 ℃ and a pressure of less than 20 MPa for a period of less than 500 minutes (not shown);

a step i) of physical separation of the sediment contained in the fraction 29 coming from the sediment precipitation step h), which makes it possible to obtain a sediment-rich fraction 30 and a hydrocarbon-based fraction 31 with a low sediment content;

-an optional step j) of separating said hydrocarbon-based fraction 31 with low sediment content in order to recover at least a portion 32 of the distillation fraction 28 introduced into the precipitation step h) and a hydrocarbon-based fraction 33 with low sediment content.

In fig. 2 and 3, embodiment variants are shown, only elements differing from the embodiment of fig. 1 being described in the following.

Fig. 2 shows a variant of fig. 1, in which the effluent 14 from the fixed bed hydrocracking step d) and the effluent 21 from the ebullated bed hydrocracking step f) are treated in a separation step g) common to both effluents. Optionally, a portion of fraction 23 may be sent to fixed bed hydrocracking step d) via line 24 and/or to deasphalting step c) via line 34.

Fig. 3 shows a variant of fig. 1, in which the effluent 4 from the fixed bed hydrotreating step a) and the effluent 14 from the fixed bed hydrocracking step d) are treated in a separation step b) common to both effluents. The term "common separation" in fig. 2 and 3 is intended to mean that at least a portion of the separation apparatus (drum, column, etc.) and preferably all of the separation apparatus is common.

The above description of fig. 1, 2 and 3 is an example of an embodiment of the present invention and is not intended to limit the invention in any way. In said figures only the main steps are shown, but it is understood that all the equipment (drums, pumps, exchangers, ovens, towers, etc.) necessary for the operation are present. Only the main stream containing hydrocarbons is shown, but it is understood that the hydrogen-rich gas stream (make-up or recycle) may be injected at the inlet of each catalytic reactor or bed or between two catalytic reactors or beds. Means for purifying and recycling hydrogen known to the person skilled in the art are also used.

The treated feedstock and the various steps of the method of the present invention are now described in more detail below.

Raw materials

The feedstock 1 treated in the process of the present invention is advantageously a hydrocarbon-based feedstock containing asphaltenes, in particular having a C7 asphaltene content of at least 1.0 wt%, preferably at least 2.0 wt%, based on the weight of the feedstock.

The feedstock 1 has an initial boiling point of at least 340 ℃ and a final boiling point of at least 600 ℃.

The hydrocarbon-based feedstock 1 of the present invention may be selected from atmospheric residues and vacuum residues obtained from direct distillation, crude oil, topped crude oil, oil sands or derivatives thereof, asphaltic schists or derivatives thereof, and source rock oils or derivatives thereof, taken alone or in admixture. In the present invention, the feedstock to be treated is preferably an atmospheric residue or a vacuum residue, or a mixture of these residues, and more preferably a vacuum residue.

The hydrocarbyl feedstock treated in the process may contain, inter alia, sulfur-based impurities. The sulfur content may be at least 0.1 wt%, at least 0.5 wt%, preferably at least 1.0 wt% and more preferably at least 2.0 wt% of the weight of the feedstock.

The hydrocarbyl feedstock treated in the process may contain, inter alia, a metal. The nickel + vanadium content may be at least 10 ppm, preferably at least 30 ppm by weight of the feedstock.

The hydrocarbyl feedstock treated in the process may contain, inter alia, conradson carbon. The conradson carbon may be present in an amount of at least 2.0 wt.%, preferably at least 5.0 wt.%, based on the weight of the feedstock.

These raw materials can be advantageously used as they are. Alternatively, they may be diluted with the auxiliary raw material 3. The co-feed 3 (different from the initial hydrocarbon-based feed 1) is introduced with the initial hydrocarbon-based feed to dilute the initial hydrocarbon-based feed. The auxiliary feed 3 may be a hydrocarbon-based fraction or a mixture of lighter hydrocarbon-based fractions, preferably selected from the products of Fluid Catalytic Cracking (FCC or Fluid Catalytic Cracking) processes, in particular light fractions (LCO or light cycle oil), heavy fractions (HCO or heavy cycle oil), decant oil, FCC residual oil. The auxiliary feedstock 3 may also be an atmospheric diesel fraction or a vacuum diesel fraction, obtained by atmospheric distillation or vacuum distillation of crude oil or of the effluent from a conversion process, such as coking or visbreaking. Such auxiliary feedstock 3 may also be a deasphalted oil obtained by deasphalting of a residual oil obtained by atmospheric or vacuum distillation of a crude oil or of an effluent from a conversion process. The auxiliary feed 3 may also advantageously be one or more fractions derived from the coal or biomass liquefaction process, aromatic extracts, or any other hydrocarbon fraction, or a non-oil feed, such as pyrolysis oil. The heavy hydrocarbonaceous feedstock 1 according to the invention can represent at least 50%, preferably 70%, more preferably at least 80% and even more preferably at least 90% by weight of the total hydrocarbonaceous feedstock (i.e. the initial heavy hydrocarbonaceous feedstock 1 as defined above and the auxiliary feedstock 3 treated by the process according to the invention).

In some cases, the auxiliary feed 3 may be introduced downstream of the first or subsequent catalytic bed of the fixed-bed hydrotreatment step a). It is also possible to introduce the auxiliary feed 13 upstream or downstream of the first catalyst bed or of the subsequent catalytic bed of the fixed bed hydrocracking step d), or to introduce the auxiliary feed 20 upstream or downstream of the first catalytic bed or of the subsequent catalytic bed of the ebullated bed hydrocracking step f); co-feeds 13 and 20 are hydrocarbon-based fractions of the type as mentioned above for co-feed 3. Very preferably, the auxiliary feedstock 13 comprises vacuum diesel and the auxiliary feedstock 20 comprises a fraction from a fluid catalytic cracking process.

Hydrotreating step a)

According to the invention, the process comprises a hydrotreating step a) carried out in a fixed bed reactor, in which at least one initial hydrocarbon-based heavy feedstock 1, optionally mixed with a co-feedstock 3, is contacted with a hydrotreating catalyst in the presence of hydrogen.

The term "hydrotreatment", commonly known as HDT, is intended to mean a catalytic treatment with a hydrogen contribution capable of refining, that is to say of significantly reducing the content of metals, sulphur and other impurities, the hydrocarbon-based feedstock while improving the hydrogen to carbon ratio of the feedstock and while partially converting the feedstock, more or less, into lighter fractions. The hydrotreatment includes in particular hydrodesulfurization (commonly known as HDS) reactions, hydrodenitrogenation (commonly known as HDN) reactions and hydrodemetallization (commonly known as HDM) reactions, accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydrodeasphaltisation reactions and conradson carbon reduction.

According to one embodiment of the invention, the hydrotreatment step a) comprises a first Hydrodemetallization (HDM) step a 1) carried out in one or more hydrodemetallization zones in a fixed bed and a subsequent second Hydrodesulfurization (HDS) step a 2) carried out in one or more hydrodesulfurization zones in a fixed bed. During the first hydrodemetallization step a 1), the feedstock and hydrogen are contacted over a hydrodemetallization catalyst under hydrodemetallization conditions, and subsequently, during the second hydrodesulphurization step a 2), the effluent from the first hydrodemetallization step a 1) is contacted with a hydrodesulphurization catalyst under hydrodesulphurization conditions. This process, known as HYVAHL-FTM, is described, for example, in patent US 5417846.

According to one embodiment of the invention, when the feedstock contains more than 70 ppm, or even more than 150 ppm, of metals and/or when the feedstock contains impurities such as iron derivatives, the interchangeable reactor (PRS technology, interchangeable reactor system) described in patent FR 2681871 is used. These interchangeable reactors are usually fixed beds located upstream of the fixed bed HDM section.

According to one embodiment of the invention, at least one of the reactors of the hydrotreatment step a), preferably the interchangeable reactor, is equipped with filtration and distribution means, such as those described in patent applications FR 3043339 and FR 3051375.

It will be readily understood by those skilled in the art that in the HDM step, the HDM reaction is carried out, but at the same time a portion of the other hydroprocessing reactions, in particular the HDS reaction, are also carried out. Also, in the HDS step, the HDS reaction is carried out, but at the same time a part of the other hydrotreating reactions, in particular the HDM reaction, are also carried out. The person skilled in the art understands that the HDM step starts when the hydrotreating step starts, that is to say when the metal concentration is at its maximum. The person skilled in the art understands that the HDS step ends when the hydrotreatment step ends, that is to say when the removal of sulphur is the most difficult. Between the HDM step and the HDS step, the skilled person sometimes defines a transition zone in which all types of hydroprocessing reactions take place.

The hydrotreating step a) of the present invention is carried out under hydrotreating conditions. It can advantageously be carried out at a temperature of from 300 ℃ to 450 ℃, preferably from 350 ℃ to 420 ℃ and at an absolute pressure of from 5 MPa to 35 MPa, preferably from 11 MPa to 20 MPa. Usually depending on the desired level of hydroprocessingAnd a target duration of the treatment to regulate the temperature. Most commonly, the space velocity of the hydrocarbon-based feedstock, commonly referred to as HSV and defined as the volumetric flow rate of the feedstock divided by the total volume of the catalyst, may be at 0.1 h ^-1To 5.0 h ^-1Preferably 0.1 h ^-1To 2.0 h ^-1And more preferably 0.1 h ^-1To 1.0 h ^-1Within the range of (1). The amount of hydrogen mixed with the feedstock can be per cubic meter (m) ³) Liquid feedstock 100 to 5000 standard cubic meters (Sm) ³) Preferably 200 Sm ³/m ³To 2000Sm ³/m ³And more preferably 300 Sm ³/m ³To 1500 Sm ³/m ³. The hydrotreating step a) can be carried out industrially in one or more fixed-bed reactors with a downward liquid stream.

The hydrotreating catalyst used is preferably a known catalyst. They may be particulate catalysts comprising at least one metal or metal-containing compound (oxide, sulfide, etc.) having a hydro-dehydrogenation function on a support. These catalysts may advantageously be catalysts comprising at least one metal from group VIII, generally selected from nickel and cobalt, and/or at least one metal from group VIB, preferably molybdenum and/or tungsten. For example, a catalyst comprising 0.5 to 10.0 wt% of nickel, preferably 1.0 to 5.0 wt% of nickel (expressed as nickel oxide NiO) and 1.0 to 30.0 wt% of molybdenum, preferably 5.0 to 20.0 wt% of molybdenum (expressed as molybdenum oxide MoO), based on the total weight of the catalyst, on an inorganic support may be used ₃) The catalyst of (1). The support is for example selected from the group consisting of alumina, silica/alumina, magnesia, clay and mixtures of at least two of these minerals. Advantageously, this support may comprise other doping compounds, in particular oxides selected from the group consisting of boron oxide, zirconium oxide, cerium oxide, titanium oxide, phosphoric anhydride and mixtures of these oxides. Alumina supports are most commonly used, very often alumina supports doped with phosphorus and optionally boron. When phosphoric anhydride P is present ₂O ₅When the concentration is less than 10.0 wt%. When boron trioxide B is present ₂O ₃When it is less thanThe total content of oxides of the group VIB and VIII metals may be from 5.0 to 40.0 wt.%, and typically from 7.0 to 30.0 wt.%, based on the total weight of the catalyst, and the weight ratio between the group VIB metal and the group VIII metal, expressed as metal oxides, is typically from 20 to 1, and most typically from 10 to 2.

In the present specification, the family of chemical elements is given according to the CAS classification (CRC Handbook of Chemistry and Physics, CRC Press publication, eds D.R. Lide, 81 th edition, 2000-. For example, group VIII of the CAS classification corresponds to the metals of columns 8, 9 and 10 of the new IUPAC classification.

In the case where the hydrotreating step includes an HDM step and a subsequent HDS step, it is preferable to use a specific catalyst suitable for each step.

Catalysts which can be used in the HDM step are shown, for example, in patent documents EP 0113297, EP 0113284, US 5221656, US 5827421, US 7119045, US 5622616 and US 5089463. HDM catalysts are preferably used in the interchangeable reactor.

Catalysts which can be used in the HDS step are shown, for example, in patent documents EP 0113297, EP 0113284, US 6589908, US 4818743 or US 6332976.

It is also possible to use mixed catalysts which are active in HDM and in HDS, both in the HDM stage and in the HDS stage, as described in patent document FR 2940143.

The catalyst used in the process of the invention is preferably subjected to an in situ or ex situ sulfidation treatment prior to injection of feed 1 in step a).

Separation step b)

The process of the invention comprises a step b) of separating the effluent from the hydrotreatment step a) into at least one light fraction 5 and a heavy fraction 7 containing compounds boiling at least 350 ℃, and optionally a heavy fraction 6 containing at least 80% of the compounds boiling at 350 to 540 ℃.

The term "light fraction" is intended to mean a hydrocarbon fraction in which at least 80% of the compounds have a boiling point of less than 350 ℃. Such light fractions contain fuel feedstock.

The term "heavy fraction containing compounds boiling at least 350 ℃ is intended to mean a hydrocarbon fraction in which at least 50% of the compounds have a boiling point greater than or equal to 350 ℃, and preferably in which at least 80% of the compounds have a boiling point greater than or equal to 350 ℃.

Preferably, the light fraction 5 obtained during the separation step b) comprises a gas phase and at least one light fraction of hydrocarbons of the naphtha, kerosene and/or diesel type. Preferably, the heavy fraction 7 comprises a vacuum distillation fraction and a vacuum residue fraction and/or an atmospheric residue fraction. More preferably, a heavy fraction 6 comprising at least 80% of the compounds boiling at 350 to 540 ℃ is withdrawn in addition to the heavy fraction 7 comprising a vacuum residue fraction containing at least 70% of the compounds boiling above 540 ℃.

This separation step b) can be carried out according to any method and any apparatus known to the person skilled in the art. The process may be selected from high or low pressure separation, high or low pressure distillation, high or low pressure stripping, and combinations of these various processes that may be operated at various pressures and temperatures.

The separation is preferably carried out in a fractionation stage, which may first comprise a High Pressure High Temperature (HPHT) separator, and optionally a High Pressure Low Temperature (HPLT) separator, followed optionally by an atmospheric distillation stage and/or a vacuum distillation stage. The effluent 4 from the hydrotreatment step a) is preferably first sent to an HPHT separator capable of obtaining a light fraction and a heavy fraction mainly containing compounds boiling at least 350 ℃. This HPHT separation is not performed according to a precise fractionation point (cut point), but is similar to a flash type separation. The fractionation point of the separation is advantageously between 200 ℃ and 400 ℃. The light fraction from the HPHT separator may then be partially condensed in a HPLT separator to obtain a gaseous fraction comprising hydrogen and a liquid fraction comprising distillate.

Preferably, said heavy fraction coming from the HPHT separator, preferably as a mixture with said liquid fraction containing distillate coming from the HPLT separator, can be subsequently fractionated by atmospheric distillation into at least one atmospheric distillation fraction (which preferably contains at least one light fraction of hydrocarbons of the naphtha, kerosene and/or diesel type), and an atmospheric residue fraction. At least a portion of the atmospheric residue fraction may also be fractionated by vacuum distillation into a vacuum distillation fraction (which preferably contains vacuum diesel), and a vacuum residue fraction. At least a portion 7 of the vacuum residue fraction and/or the atmospheric residue fraction is advantageously sent to a deasphalting step c). The vacuum residue fraction and/or a portion of the atmospheric residue fraction can also be used directly as a fuel feedstock, in particular a fuel oil feedstock, for example as a fuel oil feedstock with a low sulphur content. The vacuum residue fraction and/or a portion of the atmospheric residue fraction may also be sent to another conversion process, particularly an FCC process. A portion of the vacuum diesel fraction 6 can also be used directly as a fuel feedstock, in particular as a fuel feedstock with a low sulphur content. A portion of the vacuum diesel fraction may also be sent to another conversion process, in particular to an FCC process or a fixed bed hydrocracking process. At least a portion and very preferably all of the vacuum diesel fraction 6 is preferably passed to the fixed bed hydrocracking step d).

The gaseous fraction from the separation step b) is preferably subjected to a purification treatment to recover hydrogen and recycle it to the hydrotreatment reactor of step a) and/or the hydrocracking reactor of step d) and/or the ebullated bed hydrocracking reactor f). The presence of a separation step b) between the hydrotreating step a) and the fixed bed hydrocracking step d) on the one hand and the ebullated bed hydrocracking step f) on the other hand advantageously enables three separate hydrogen circuits (hydrogenic circuits), one connected to the hydrotreating of step a), one to the hydrocracking of step d) and the other to the hydrocracking of step f), and which may be connected to each other as required. The hydrogen make-up can be carried out in the hydrotreating step a) stage and/or in the hydrocracking step d) stage and/or in the hydrocracking step f) stage. The recycled hydrogen can be fed to the hydrotreating step a) and/or the hydrocracking step d) and/or the hydrocracking step f). The compressor may optionally be shared by two or three hydrogen circuits. The fact that two or three hydrogen circuits can be connected enables optimization of the hydrogen management and limits the costs in terms of compressors and/or plants for purifying the gaseous effluent. Various hydrogen management embodiments that can be used in the present invention are described in patent application FR 2957607.

The light fraction 5 obtained at the end of the separation step b), which comprises hydrocarbons of naphtha, kerosene and/or diesel type, can be exploited according to methods known to the person skilled in the art. The resulting product may be integrated into a fuel formulation, typically a fuel (also referred to as a fuel pool), or may undergo additional refining steps.

The naphtha, kerosene, diesel fraction of the light fraction 5 and the vacuum diesel of the heavy fraction 6 may be subjected to one or more treatments, such as hydrotreating, hydrocracking, isomerization, catalytic reforming, catalytic cracking or thermal cracking, to bring them, alone or as a mixture, to the required specifications, which may relate to sulphur content, smoke point, octane number, cetane number, etc.

The light fraction 5 obtained at the end of stage b) can be used at least in part to form the distillation fraction 28 of the invention, which is used in the sediment precipitation stage h).

Deasphalting step c)

According to the process of the invention, the heavy fraction 7 coming from the separation step b) and containing compounds boiling at least 350 ℃ is subjected to a deasphalting step c) by means of a solvent or a mixture of solvents 8, which makes it possible to obtain, on the one hand, a fraction 10 comprising bitumen and, on the other hand, a fraction 11 comprising DAO 11. Whereby a liquid-liquid extraction operation is carried out by means of at least one hydrocarbon-based solvent 8.

According to one embodiment of the invention, a small portion of feed 1 can be injected directly at the inlet of the deasphalting step c), this portion bypassing the hydrotreating step a) and the separation step b).

The deasphalting step c) is preferably carried out under specific conditions capable of obtaining a good quality of DAO 11 (preferably with a low asphaltene content) and a good quality of bitumen 10 (preferably with a relatively low viscosity and with a moderate softening point).

This deasphalting step c) is preferably carried out in a single step by contacting the deasphalted feedstock, i.e. the heavy fraction 7 coming from step b), optionally with a portion of the initial heavy hydrocarbon-based feedstock 1, with a solvent or solvent mixture 8 containing hydrocarbons, so as to obtain a fraction 10 comprising bitumen and a fraction 11 comprising DAO, step c) advantageously being carried out under subcritical conditions, that is to say conditions below the critical point, of the solvent or solvent mixture 8 used. A non-polar solvent or a mixture of non-polar solvents or a mixture of polar and non-polar solvents may be used.

Step c) may be carried out in an extraction column or extractor, or in a mixer-decanter. Step c) is preferably carried out in an extraction column comprising liquid-liquid contactors (packing elements and/or trays, etc.) placed in one or more zones. Preferably, the solvent or solvent mixture 8 of the present invention is introduced into the extraction column at two different levels. Preferably, the deasphalted feedstock is introduced into the extraction column at only one introduction level, generally as a mixture with at least a portion of the solvent or solvent mixture 8 and generally below the first zone of the liquid-liquid contactor. Preferably, another portion of solvent or solvent mixture 8 is injected below the deasphalted feedstock, typically below the second zone of the liquid-liquid contactor above which the deasphalted feedstock is injected.

Step c) is carried out under subcritical conditions of said solvent or solvent mixture 8. Step c) is carried out at a temperature advantageously ranging from 50 to 350 ℃, preferably from 80 to 320 ℃, more preferably from 120 to 310 ℃ and even more preferably from 150 to 300 ℃ and a pressure advantageously ranging from 0.1 to 6 MPa, preferably from 1 to 6 MPa and more preferably from 2 to 5 MPa.

The ratio of the volume of solvent or solvent mixture 8 to the mass of heavy fraction 7 obtained from step b) is generally from 1/1 to 10/1, preferably from 2/1 to 8/1 (expressed in liters/kg). This ratio includes all solvents or solvent mixtures that may be divided into multiple injection points.

The polar solvent used may be selected from naphthenic-aromatic or purely aromatic solvents, polar solvents containing a hetero-element, or mixtures thereof. The aromatic solvent is advantageously selected from mono-aromatic hydrocarbons, preferably benzene, toluene or xylene, alone or as a mixture; a di-or polyaromatic hydrocarbon; cycloalkane-aromatic hydrocarbons such as tetralin or indane; heteroatom (oxy, nitro or thio) aromatic hydrocarbons or any other class of compounds with higher polarity than saturated hydrocarbons, such as dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) or Tetrahydrofuran (THF). The polar solvent used in the deasphalting step of the process of the present invention may be an aromatic-rich fraction. The aromatic-rich fraction of the invention may be, for example, a fraction from an FCC, such as heavy gasoline or LCO, or a fraction from a petrochemical plant or refinery. Mention may also be made of fractions derived from coal, biomass or biomass/coal mixtures, optionally containing residual petroleum feedstocks after thermochemical conversion with or without hydrogen and with or without catalyst. Preferably, the polar solvent used is a mono-aromatic hydrocarbon, which is pure, or mixed with an aromatic hydrocarbon.

According to one selective deasphalting embodiment comprising a combination of polar and non-polar solvents, a portion or all of the mixture of polar and non-polar solvents is injected at a first point, while the other portion of the solvent or mixture of polar and non-polar solvents is injected at a second point. According to this embodiment, preferably, a polar solvent heavier than the non-polar solvent is injected into the nadir.

The non-polar solvent used is preferably a solvent consisting of one or more saturated hydrocarbons containing a carbon number greater than or equal to 3, preferably from 3 to 5. These solvents are used in pure form or in the form of mixtures (for example, mixtures of light petroleum fractions of the alkane and/or cycloalkane or naphtha type).

Preferably, the solvent 8 used in step c) is a non-polar solvent, at least 80% by volume of which consists of one or more saturated hydrocarbons comprising a carbon number greater than or equal to 3, preferably ranging from 3 to 4, thus obtaining a bitumen having a rather low viscosity and having a moderate softening point to facilitate the high-pressure pumping of the ebullated bed hydrocracking step f), in particular of the bituminous fraction.

The choice of the temperature and pressure conditions for the extraction combined with the choice of the nature of the solvent 8 in the deasphalting step c) enables the extraction performance to be adjusted. Step c) through these specific deasphalting conditions it is possible to precipitate the maximum amount of polar structures of the heavy resins and of the asphaltene type from the bituminous fraction 10, thus making it possible to obtain the bituminous fraction 10 with an improved yield, which is generally greater than 50%, or even greater than 70%, of the amount of compounds boiling at temperatures higher than 540 ℃ at the inlet of the deasphalting step c). Moreover, the softening point of bitumen is moderate, typically less than 90 ℃, or even less than 70 ℃; typically, the viscosity is moderate, typically less than 20000cSt at 100 ℃, or even less than 10000 cSt at 100 ℃. The low viscosity of the pitch is required to ensure its pumpability at high pressure in the ebullated bed hydrocracking step f). Said high pitch yield enables more conversion products to be obtained at the outlet of the ebullated bed hydrocracking step f). At the same time, the DAO fraction 11 is obtained with a moderate yield, typically less than 50%, or even less than 30% of the amount of compounds boiling above 540 ℃ at the inlet of the deasphalting step C), this fraction 11 being of high purity and containing very little asphaltenes, typically less than 500 ppm of C7 asphaltenes, or even less than 300 ppm of C7 asphaltenes.

The fraction comprising DAO 11 and a portion of the solvent or solvent mixture is recovered at the top of the extraction column or mixer-decanter, preferably above the uppermost liquid-liquid contactor zone.

Fraction 10 comprising bitumen and a portion of the solvent or solvent mixture is recovered at the bottom of the extraction column or mixer-decanter, preferably below the lowest located liquid-liquid contactor zone.

According to one embodiment, in step c) extraction flux 9 is injected to mix with fraction 10 containing bitumen, so that said fraction is extracted more easily. Preferably, injection of the extraction flux 9 is not necessary.

The fluxing agent used may be any solvent or mixture of solvents capable of dissolving or dispersing the bitumen. The fluxing agent may be a polar solvent selected from the group consisting of: monoaromatic hydrocarbons, preferably benzene, toluene or xylene; a di-or polyaromatic hydrocarbon; aromatic cycloalkanes-hydrocarbons such as tetralin or indane; a heteroatom aromatic hydrocarbon; polar solvents with a molecular weight corresponding to a boiling point of 200 ℃ to 600 ℃, such as LCO (light cycle oil from FCC), HCO (heavy cycle oil from FCC), FCC slurry, HCGO (heavy coker gas oil), or aromatic extracts or additional aromatic fractions extracted from the oil chain, VGO fractions from residual fractions and/or conversion of coal and/or biomass. The ratio of the volume of flux to the mass of bitumen is determined so that the mixture can be easily pumped out.

The solvent or solvent mixture 8 may consist of a portion recycled during the make-up (top-up) and/or separation steps. These additions are necessary to compensate for solvent losses in the fraction 10 comprising bitumen and/or the fraction comprising DAO 11. These losses are small but cannot be avoided because the separation step is not perfect in terms of definition.

The deasphalting step c) comprises the integrated sub-step of separating the fraction comprising DAO from the solvent or solvent mixture. The fraction comprising DAO from the extraction is subjected to a separation sub-step, making it possible to obtain DAO 11 on the one hand and the solvent or solvent mixture introduced during the deasphalting step c) on the other hand. The recovered solvent or solvent mixture may be recycled in the deasphalting step c).

Such an integrated separation sub-step capable of separating DAO 11 from the solvent or solvent mixture may employ all the required equipment known to the person skilled in the art (settling drums, distillation or stripping columns, heat exchangers, ovens, pumps, compressors, etc.).

At least a portion of the DAO 11 is sent to a fixed bed hydrocracking step d). Optionally, a portion of the DAO may also be used directly as a fuel feedstock, particularly as a fuel feedstock with low sulfur content. It is also possible to send a portion of the DAO to another conversion process, in particular to an FCC process.

The deasphalting step c) comprises a further integrated sub-step of separating the fraction containing the bitumen from the solvent or solvent mixture. The fraction containing bitumen from this extraction is subjected to a separation sub-step (substep) which makes it possible to obtain, on the one hand, bitumen 10 and, on the other hand, the solvent or solvent mixture introduced during the deasphalting step c). The recovered solvent or solvent mixture may be recycled in the deasphalting step c).

At least a portion of pitch 10 is sent to ebullated bed hydrocracking step f). Optionally, a portion of the bitumen may also be used directly as a fuel feedstock, particularly as a fuel feedstock with low sulfur content. It is also possible to send a portion of the bitumen to another conversion process, in particular to a coking process. A portion of the bitumen may also serve as a feedstock for the manufacture of asphalt.

Fixed bed hydrocracking step d)

According to the invention, at the end of the deasphalting step c), at least part of the DAO fraction 11 obtained in step c) is sent to a fixed bed hydrocracking step d).

Hydrogen 12 may also be injected upstream of the various catalytic beds that make up the hydrocracking reactor. In parallel with the hydrocracking reactions desired in this step, any type of hydrotreating reaction (HDM, HDS, HDN, etc.) may also take place. The atmospheric hydrocracking reactions that result in distillate formation are conducted at levels generally greater than 30%, typically 30% to 50% for mild hydrocracking and greater than 80% for higher hydrocracking vacuum distillates converted to atmospheric distillates. Specific conditions, in particular temperature conditions and/or the use of one or more specific catalysts, can promote the desired hydrocracking reactions.

The hydrocracking step d) of the present invention is carried out under hydrocracking conditions. It can advantageously be carried out at a temperature of from 340 ℃ to 480 ℃, preferably from 350 ℃ to 430 ℃, and at an absolute pressure of from 5 MPa to 25 MPa, preferably from 8MPa to 20 MPa, preferably from 10 MPa to 18 MPa. The temperature is typically adjusted according to the desired level of hydroprocessing and the target duration of the treatment. Most commonly, the space velocity of the hydrocarbon-based feedstock, commonly referred to as HSV and defined as the volumetric flow rate of the feedstock divided by the total volume of the catalyst, may be at 0.1 h ^-1To 3.0 h ^-1Preferably 0.2 h ^-1To 2.0 h ^-1And more preferably 0.25 h ^-1To 1.0 h ^-1Within the range of (1). The amount of hydrogen mixed with the feedstock can be per cubic meter (m) ³) Liquid feedstock 100 to 5000 standard cubic meters (Sm) ³) Preferably 200 Sm ³/m ³To 2000Sm ³/m ³And more preferably 300 Sm ³/m ³To 1500 Sm ³/m ³. The hydrocracking step d) can be carried out industrially in at least one reactor with a downward liquid stream.

The hydrocracking step d) generally comprises two catalytic stages in series, the upstream hydrotreating catalytic stage to limit the deactivation of the downstream hydrocracking catalytic stage. The hydrotreating section is particularly intended to significantly reduce the nitrogen content of the feedstock, nitrogen being an inhibitor of the acid functionality of the bifunctional catalyst of the hydrocracking catalytic section. The hydrocracking step d) may also comprise a second hydrocracking catalytic stage, which treats at least one heavy fraction coming from the separation step.

The catalysts used in the hydrocracking step d) may be hydrotreating and hydrocracking catalysts.

The hydrotreating catalyst used may be a hydrotreating catalyst consisting of a support of the inorganic oxide type, preferably alumina, and an active phase containing chemical elements from group VIII (Ni, Co, etc.) and group VI (Mo, etc.) of the periodic table.

The hydrocracking catalyst may advantageously be a bifunctional catalyst, having a hydrogenation phase so as to be able to hydrogenate aromatics and to create an equilibrium between saturated compounds and the corresponding olefins, and an acid phase able to promote hydroisomerization and hydrocracking reactions. The acid function is advantageously composed of a material exhibiting surface acidity with a high surface area (typically 100 to 800 m) ².g ^-1) Such as halogenated (especially chlorinated or fluorinated) alumina, combinations of boron and aluminum oxides, amorphous silica/alumina and zeolites. The hydrogenation function is advantageously provided by one or more metals from group VIII of the periodic table, such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, or by a combination of at least one metal from group VIB of the periodic table, such as molybdenum and tungsten, and at least one non-noble metal from group VIII, such as nickel and cobalt. Preferably, the bifunctional catalyst used comprises at least one metal from groups VIII and VIB, taken alone or in a mixture, and comprises from 10% to 90% by weight of zeolite and from 90% to 10% by weight of zeoliteAmount% of a support of an inorganic oxide. The metals from group VIB used are preferably selected from tungsten and molybdenum, and the metals from group VIII are preferably selected from nickel and cobalt. According to another preferred variant, the monofunctional and bifunctional catalysts of the alumina, amorphous silica-alumina or zeolite type can be used as a mixture or in successive layers.

Preferably, the catalytic volume used during the second hydrocracking step d) consists of at least 30% of a hydrocracking catalyst of the bifunctional type.

Optionally, the auxiliary feedstock 13 can be injected upstream of any catalytic bed of the hydrocracking section d). Such co-feeds are typically vacuum distillates from direct distillation or from conversion processes, or deasphalted oils.

Optionally, a heavy fraction 6 coming from the separation step b) and containing at least 80% of the compounds boiling at 350 to 540 ℃ can also be injected upstream of any catalytic bed of the hydrocracking step d). Preferably, the heavy fraction 6 previously purified in step a) is injected directly at the inlet of the downstream hydrocracking catalytic section.

Optionally, a heavy fraction 24 coming from the separation step b) and containing at least 80% of the compounds boiling at 350 to 540 ℃ can also be injected upstream of any catalytic bed of the hydrocracking step d).

Optionally, the fixed bed hydrocracking step d) can be carried out according to a single step type mode with recycling, with recycling of at least a portion of the heavy fraction 18 upstream of the hydrotreatment catalytic section upstream of step d) or upstream of the hydrocracking catalytic section downstream of step d), to increase the conversion.

Optionally, the fixed bed hydrocracking step d) can be carried out according to a two-stage type mode with recycling, with recycling of at least a portion of the heavy fraction 18 upstream of the second hydrocracking catalytic section of step d) to increase the overall conversion.

In an embodiment variant, the effluent 14 from the fixed bed hydrocracking step d) is sent to the separation step b).

Optional step e) of separating the fixed bed hydrocracking effluent

The effluent obtained at the end of the fixed bed hydrocracking step d) comprises a liquid hydrocarbon fraction and a gaseous fraction. This effluent is advantageously separated in at least one settling drum into at least one gaseous fraction 15 and at least one heavy liquid fraction 16. The effluent may be separated using separation means well known to those skilled in the art, in particular using one or more settling drums which may be operated at different pressures and temperatures, optionally in combination with steam or hydrogen stripping means and with one or more distillation columns. These separators may be, for example, High Pressure High Temperature (HPHT) separators and/or High Pressure Low Temperature (HPLT) separators.

The gas fraction contains a gas, in particular H ₂、H ₂S、NH ₃And C1-C4 hydrocarbons. After optional cooling, the gaseous fraction is preferably treated in a hydrogen purification unit in order to recover hydrogen not consumed during the hydrocracking step d). The hydrogen purification unit, which may be common to the unit that processes the gaseous fraction separated from the effluents from the hydrotreating step a) and the ebullated bed hydrocracking step f), may be scrubbed with an amine, a membrane, a PSA type system, or a plurality of such units arranged in series.

The purified hydrogen can then advantageously be recycled in the process of the invention. The hydrogen may be recycled at the inlet and/or at various locations of the hydrotreating step a) and/or the fixed bed hydrocracking step d) and/or the ebullated bed hydrocracking step f). The recycling of hydrogen can optionally be carried out by recompression or expansion in order to reach the desired pressure at the inlet of step a), d) or f).

In a preferred embodiment, this second separation step e) comprises, in addition to a gas-liquid separation or continuous separation device, at least one atmospheric distillation, in which the liquid hydrocarbon-based fraction obtained after separation is fractionated by atmospheric distillation into at least one atmospheric distillation fraction (stream not shown in the figure) and at least one desulfurized heavy fraction 16 consisting of unconverted vacuum distillate. The atmospheric distillation fraction may contain fuel feedstocks (naphtha, kerosene and/or diesel) that may be commercially upgraded (e.g., in a refinery) to produce motor vehicle and aviation fuels. The kerosene and/or diesel-type fractions can also be used as raw materials in distillate-type tanks for ships or as fluxing agents in residue-type fuel oils or fuel oil tanks for boilers for ships (according to ISO 8217). The unconverted vacuum distillate type fraction can advantageously be exploited as a marine fuel having a sulphur content of less than 0.5% or 0.1%, in particular as a feedstock in a pool of marine distillate type having a sulphur content of less than 0.5% or 0.1% or as a fluxing agent in a residual oil type fuel oil or in a pool of marine boiler fuel oil (according to ISO 8217).

Optionally, at least a portion of the fraction 18 of unconverted vacuum distillate type is recycled to the hydrocracking step d), and according to this variant it may be necessary to carry out a flushing consisting of the fraction 16 of unconverted vacuum distillate type in order to disperse the polyaromatic species and limit the deactivation of the hydrocracking catalyst of step d). In order to limit this flushing and thus increase the overall conversion, it may be advantageous to optionally carry out this flushing by sending at least part of the fraction 17 of unconverted vacuum distillate type to the inlet of the deasphalting step c) in order to at least partially remove the polyaromatic species in the bituminous fraction 10.

Fluidized bed hydrocracking step f)

According to the process of the invention, step f) of hydrocracking at least a portion of the fraction of bitumen 10 coming from the deasphalting step c) is carried out in at least one ebullating bed reactor in the presence of a hydrocracking catalyst and hydrogen 19.

Whereby at least a portion of the fraction of bitumen 10 coming from the deasphalting step c) is sent to the hydrocracking step f) which is carried out in at least one reactor, advantageously in two reactors, containing at least one ebullated bed hydrocracking catalyst. The hydrocracking catalyst is advantageously a supported catalyst. The reactor may be operated with upward liquid and gas streams. The main purpose of hydrocracking is to convert the hydrocracked feedstock (which is a heavy hydrocarbon-based feedstock) into lighter fractions while partially refining it.

According to one embodiment, a small portion of the initial hydrocarbon-based feedstock 1 can be injected directly at the inlet of the ebullated bed hydrocracking step f) as a mixture with at least a portion of the bituminous fraction 10 coming from step c), this portion of initial heavy hydrocarbon-based feedstock 1 not being treated in the hydrotreating step a) and the deasphalting step c). This embodiment may be similar to partially bypassing the hydrotreating step a) and deasphalting step c).

According to one embodiment, the auxiliary feedstock 20 may be injected at the inlet of the first or subsequent ebullated-bed reactor.

According to one embodiment, the heavy fraction 26 coming from the separation step g) can be injected at the inlet of the first or subsequent ebullated-bed reactor.

The hydrogen 19 required for the hydrocracking reaction is introduced at the inlet of the hydrocracking step f). In the case where the hydrocracking step has a plurality of ebullated bed reactors, hydrogen may be injected at the inlet of each reactor. The hydrogen injected can be a make-up stream and/or a recycle stream.

Ebullated bed technology is well known to those skilled in the art. Only the main operating conditions are described here. Ebullated bed technology conventionally uses supported catalysts in the form of extrudates, typically about 1 mm in diameter or less. The catalyst remains inside the reactor and is not discharged with the product, except during the phases of make-up and removal of the catalyst required to maintain catalytic activity. The temperature level can be higher to obtain high conversion while minimizing the amount of catalyst used. The catalytic activity can be kept constant by replacing the catalyst on-line. It is not necessary to stop the apparatus to replace the spent catalyst or to raise the reaction temperature during the cycle to compensate for the deactivation. Furthermore, operating at constant operating conditions can advantageously achieve constant product yield and quality during cycling. Also, the head loss (head load) on the reactor remains low and constant, since the catalyst is kept agitated by a considerable amount of liquid recirculation.

The conditions of the ebullated bed hydrocracking step f) may be conventional conditions for ebullated bed hydrocracking of hydrocarbon-based feedstocks. The process is advantageously carried out at an absolute pressure of from 2.5 MPa to 35.0 MPa, preferably from 5.0 MPa to 25.0 MPa, more preferably from 6 MPa to 20 MPa and even more preferably from 11 MPa to 20 MPa. The process is advantageously carried out at a temperature of from 330 ℃ to 540 ℃, preferably from 350 ℃ to 500 ℃. The reactor space velocity (HSVr) and the hydrogen partial pressure are parameters that are fixed according to the characteristics of the product to be treated and the desired conversion. HSVr (which is defined as the volumetric flow rate of the feed to the hydrocracking step divided by the total reactor volume) is typically 0.1 h ^-1To 10.0 h ^-1Preferably 0.1 h ^-1To 5.0 h ^-1And more preferably 0.1 h ^-1To 1.0 h ^-1. The amount of hydrogen mixed with the feed to the hydrocracking step is generally in the range of per cubic meter (m) ³) Liquid feedstock 50 to 5000 standard cubic meters (Sm) ³) Most typically 100Sm ³/m ³To 1500 Sm ³/m ³And preferably 200 Sm ³/m ³To 1200 Sm ³/m ³。

Conventional particulate hydrocracking catalysts comprising at least one metal or metal-containing compound (oxide, sulfide, etc.) having a hydro-dehydrogenation function on a mineral support may be used. The catalyst may be a catalyst comprising a metal from group VIII, such as nickel and/or cobalt, most typically in combination with at least one metal from group VIB, such as molybdenum and/or tungsten. For example, nickel may be used in an amount of 0.5 to 10.0 wt.%, preferably 1.0 to 5.0 wt.% (expressed as nickel oxide NiO) and molybdenum in an amount of 1.0 to 30.0 wt.%, preferably 5.0 to 20.0 wt.% (expressed as molybdenum oxide MoO), based on the total weight of the catalyst, on an inorganic support ₃) The catalyst of (1). The support may be selected, for example, from the group consisting of alumina, silica/alumina, magnesia, clay and mixtures of at least two of these minerals. The support may also contain other compounds, for example oxides selected from the group consisting of boron oxide, zirconium oxide, titanium oxide, phosphoric anhydride. Alumina supports are most commonly used, very often alumina supports doped with phosphorus and optionally boron. When phosphoric anhydride P is present ₂O ₅When present, the concentration is typically less than 20% by weight, most typically less than10% by weight. When boron trioxide B is present ₂O ₃The total content of oxides of metals of groups VI and VIII may be from 5 to 40 wt.%, preferably from 7 to 30 wt.%, and the weight ratio of group VI metal to group VIII metal, expressed as metal oxide, is from 20 to 1, preferably from 10 to 2.

The spent catalyst can be partially replaced by fresh catalyst, which is generally withdrawn at regular intervals at the bottom of the reactor and introduced at the top of the reactor either fresh or fresh, that is to say batch (in bursts) or continuous or quasi-continuous. The catalyst can also be introduced via the bottom and withdrawn via the top of the reactor. Fresh catalyst may be introduced, for example, daily. The extent of replacement of spent catalyst with fresh catalyst may be, for example, from 0.05 kg to about 10 kg per cubic meter of hydrocracking step feedstock. The withdrawal and the replacement are carried out using means which enable the hydrocracking step to be carried out continuously. The hydrocracking reactor typically contains a circulation pump which is capable of maintaining the catalyst in an ebullated bed by continuously recycling at least a portion of the liquid withdrawn at the top of the reactor and reinjecting it at the bottom of the reactor. The spent catalyst withdrawn from the reactor can also be sent to a regeneration zone where the carbon and sulphur contained in the spent catalyst are removed and subsequently re-injected into the hydrocracking step f).

The hydrocracking step f) of the process of the present invention may be carried out under conditions such as the H-OIL ® process described in patent US 6270654B.

The ebullated bed hydrocracking may be carried out in a single reactor or in a plurality of reactors, preferably two reactors, arranged in series. The use of at least two ebullated bed reactors in series enables a better quality and better yield of product to be obtained. Furthermore, hydrocracking in both reactors can have improved operability in terms of operating conditions and flexibility of the catalytic system. Preferably, the temperature of the second ebullated-bed reactor is at least 5 ℃ higher than the temperature of the first ebullated-bed reactor. The pressure of the second reactor may be between 0.1 MPa and 1.0 MPa lower than the pressure of the first reactor to allow at least a portion of the effluent from the first step to flow without pumping. The various operating conditions in the two hydrocracking reactors in terms of temperature are selected so as to be able to control the hydrogenation of the feed to the hydrocracking step in each reactor and the conversion to the desired products.

In the hydrocracking step f) in two sub-steps (f) in two reactors arranged in series ₁) And (f) ₂) In the case of implementation, the first substep f may optionally be performed ₁) The effluent obtained at the end is subjected to a step of separating a light fraction from a heavy fraction and may be subjected to a second hydrocracking substep f ₂) At least a portion, preferably all, of the heavy fraction is treated. This separation is advantageously carried out in an interstage separator as described in patent US 6270654B and in particular makes it possible to avoid excessive cracking of the light fraction in the second hydrocracking reaction. It is also possible to start the first hydrocracking sub-step (f) operating at a lower temperature ₁) The whole or part of the spent catalyst withdrawn from the reactor(s) is transferred directly to a second substep (f) operating at a higher temperature ₂) Or will be from the second substep (f) ₂) Is transferred directly to the first substep (f) ₁) In the reactor (2). Such a cascade system is described, for example, in patent US 4816841B.

In the case of large production capacities, the hydrocracking step can also be carried out with a plurality of (usually two) reactors in parallel. The hydrocracking step may thus comprise a plurality of stages in series, optionally separated from interstage separators, each stage consisting of one or more reactors in parallel.

Step g) of separating the effluent of the ebullated bed hydrocracking

According to the invention, the process also comprises a step g) of separating the effluent 21 from hydrocracking step f) into a gaseous fraction 22 and at least one heavy liquid fraction 25.

The effluent 21 obtained at the end of hydrocracking step f) comprises at least one liquid heavy fraction andcontaining gases, especially H ₂、H ₂S、NH ₃And C ₁-C ₄A gaseous fraction of hydrocarbons, that is to say containing from 1 to 4 carbon atoms. The heavy liquid fraction is a hydrocarbon-based liquid fraction containing compounds boiling at least 350 ℃, in particular a liquid fraction of hydrocarbons in which at least 50% of the compounds have a boiling point greater than or equal to 350 ℃ and preferably in which at least 80% of the compounds have a boiling point greater than or equal to 350 ℃.

This gaseous fraction 22 can be separated from the effluent 21 using separation means well known to those skilled in the art, in particular using one or more settling drums which can be operated at different pressures and temperatures, optionally in combination with steam or hydrogen stripping means and with one or more distillation columns. The effluent 21 obtained at the end of hydrocracking step f) is advantageously separated in at least one settling drum into at least one gaseous fraction 22 and at least one heavy liquid fraction 25. These separators may be, for example, High Pressure High Temperature (HPHT) separators and/or High Pressure Low Temperature (HPLT) separators.

After optional cooling, the gaseous fraction 22 is preferably treated in a hydrogen purification unit in order to recover hydrogen not consumed in the hydrocracking reaction. The hydrogen purification unit, which may be common with the unit that treats the separated gas fractions of the effluents from the hydrotreating step a) and the fixed bed hydrocracking step d), may be scrubbed with an amine, a membrane, a PSA type system, or a plurality of such units arranged in series.

The purified hydrogen can then advantageously be recycled in the process of the invention. The hydrogen may be recycled at the inlet and/or at various locations of the hydrotreating step a) and/or the fixed bed hydrocracking step d) and/or the ebullated bed hydrocracking step f). The recycling of hydrogen can optionally be carried out by recompression or expansion in order to reach the desired pressure at the inlet of step a), d) or f).

The separation step g) may also comprise atmospheric distillation and/or vacuum distillation. Advantageously, the separation step g) also comprises at least one atmospheric distillation, wherein the liquid hydrocarbon-based fraction obtained after the separation is fractionated by atmospheric distillation to provide at least one atmospheric distillation fraction and at least one atmospheric residue fraction. The atmospheric distillation fraction may contain fuel feedstocks (naphtha, kerosene and/or diesel), which may be exploited commercially directly or, after an optional hydrotreatment step (for example in a refinery), for the production of fuels for the motor vehicle and aeronautical sectors. The naphtha can also be developed and utilized in petrochemical industry.

The separation step g) of the process of the present invention may also comprise at least one vacuum distillation, wherein the liquid hydrocarbon-based fraction obtained after the separation and/or the atmospheric residue fraction obtained after the atmospheric distillation is fractionated by vacuum distillation to provide at least one vacuum distillation fraction 23 and at least one vacuum residue fraction. Preferably, the separation step g) comprises first an atmospheric distillation wherein the liquid hydrocarbon-based fraction obtained after the separation is fractionated by atmospheric distillation to provide at least one atmospheric distillation fraction and at least one atmospheric residue fraction, and subsequently a vacuum distillation wherein the atmospheric residue fraction obtained after the atmospheric distillation is fractionated by vacuum distillation to provide at least one vacuum distillation fraction and at least one vacuum residue fraction. The vacuum distillation fraction typically contains a vacuum gas oil type fraction.

Preferably, a portion of the heavy fraction obtained in step g) is recycled to deasphalting step c).

Preferably, a portion of the heavy fraction obtained in step g) is recycled to the ebullated bed hydrocracking step f).

At least a portion of the atmospheric resid fraction and/or a portion of the vacuum resid fraction can be recycled via line 26 to the ebullated bed hydrocracking step f) and/or via line 27 to the deasphalting step c).

At least a portion of the vacuum distillation fraction may be sent to fixed bed hydrocracking step d) via line 24.

The atmospheric distillation fraction (stream not shown) obtained at the end of step g) can be used at least in part to form the distillation fraction 28 of the invention, this distillation fraction 28 being used in the sediment precipitation step h).

Precipitation of the sediment step h)

According to the invention, the process comprises a step h) of precipitation of the sediment of the heavy liquid fraction 25 coming from the separation step g).

The precipitation step h) may be carried out by:

contacting the heavy liquid fraction 25 from step g) with an oxidizing agent at a temperature of from 25 to 350 ℃ and at a pressure of less than 20 MPa for a time of less than 500 minutes;

or contacting the heavy liquid fraction 25 coming from step g) with a distillation fraction 28 at a temperature ranging from 25 to 350 ℃ and at a pressure lower than 20 MPa for a time lower than 500 minutes, at least 20% by weight of said distillation fraction 28 having a boiling point higher than or equal to 100 ℃.

The heavy liquid fraction 25 obtained at the end of the separation step g) may contain organic sediment resulting from ebullated bed hydrotreating, deasphalting and hydrocracking conditions and catalyst residues. A portion of the sediment consisted of asphaltenes precipitated under ebullated bed hydrotreating and hydrocracking conditions and was analyzed as prior sediment (IP 375). The measurement uncertainty of the IP375 method is. + -. 0.1 for contents smaller than 3 and. + -. 0.2 for contents greater than or equal to 3.

The sediment content in the heavy liquid fraction varies with ebullated bed hydrocracking conditions. From an analytical point of view, the existing sediment (IP 375) is different from the aged sediment (IP 390), which includes potential sediment. In fact, advanced ebullated bed hydrocracking conditions (that is to say when the degree of conversion of the ebullated bed hydrocracking step is for example greater than 40% or 50%) result in the formation of existing and potential sediments.

In order to obtain a fuel or fuel oil feedstock, in particular a fuel oil or fuel oil feedstock corresponding to the recommended standard of the content of sediment after ageing (IP 390) of less than or equal to 0.1%, the process of the invention comprises a precipitation step which enables an improvement in the efficiency of the separation of the sediment and thus a fuel or fuel oil feedstock, for example a fuel oil or fuel oil feedstock, to be obtained which is stable, that is to say a content of sediment after ageing of less than or equal to 0.1% by weight. The sediment content after ageing was determined by the IP390 method with a measurement uncertainty of ± 0.1.

When step h) of the process of the invention is carried out by contacting the heavy liquid fraction 25 from step g) in the presence of an oxidizing agent, the contacting may be carried out in the presence of an oxidizing gas, such as oxygen, or in the presence of a mixture comprising an inert gas and an oxidizing gas, such as air or nitrogen-depleted air. The use of oxidizing gases can accelerate the maturation process. The contacting can also be carried out in the presence of an oxidizing liquid, alone or as a mixture with an oxidizing gas. By definition, the oxidizing gas or liquid used in the present invention contains a species capable of acquiring one or more electrons. For example, oxidizing liquids containing oxygen-containing species, in particular acids, oxides, peracids or peroxides, can be used.

When step h) of the process of the invention is carried out by contacting the heavy liquid fraction 25 coming from the separation step g) with a distillation fraction 28, at least 20% by weight of said distillation fraction 28 has a boiling point greater than or equal to 100 ℃, preferably greater than or equal to 120 ℃, more preferably greater than or equal to 150 ℃. Advantageously, this distillation fraction 28 is characterized in that it comprises at least 25% by weight of fractions having a boiling point greater than or equal to 100 ℃, preferably greater than or equal to 120 ℃, more preferably greater than or equal to 150 ℃.

Advantageously, at least 5 wt.%, or even 10 wt.% of the distillation fraction of the invention has a boiling point of at least 252 ℃. More advantageously, at least 5% by weight, or even 10% by weight, of the distillation fraction of the invention has a boiling point of at least 255 ℃.

Said distillation fraction 28 may come partly or even entirely from the separation step b) and/or e) and/or g) of the process of the invention or from another refining process or another chemical process.

The use of the distillation fraction 28 according to the invention has the following advantages: the major use of fractions with high added value, such as petrochemical fractions, naphtha, etc., is eliminated. Furthermore, the use of the distillation fraction 28 enables an improved yield of the heavy liquid fraction 31 separated from the sediment in the physical separation step i) of the sediment. Indeed, according to the invention, the use of this distillation fraction 28 makes it possible to keep the utilizable compounds dissolved in the heavy liquid fraction to be separated from the sediment, as opposed to using a fraction with a lower boiling point, in which these utilizable compounds will precipitate with the sediment.

The distillation fraction 28 advantageously comprises hydrocarbons having more than 12 carbon atoms, preferably hydrocarbons having more than 13 carbon atoms, more preferably hydrocarbons having from 13 to 40 carbon atoms. The distillation fraction 28 may be used as a mixture with a naphtha type fraction and/or a vacuum diesel type fraction. In the case where this distillation fraction 15 is mixed with another fraction, the ratio is selected so that the resulting mixture meets the characteristics of the distillation fraction 15 of the present invention.

The precipitation step h) of the present invention enables all existing sediment and potential sediment to be obtained (by converting potential sediment into existing sediment), thereby efficiently separating sediment and thereby achieving an aged sediment content (IP 390) of at most 0.1 wt%.

Whatever the embodiment adopted, the precipitation step h) of the invention is carried out at a temperature ranging from 25 to 350 ℃, preferably from 50 to 350 ℃, more preferably from 65 to 300 ℃ and even more preferably from 80 to 250 ℃ and at a pressure of less than 20 MPa, preferably less than 10 MPa, more preferably less than 3 MPa and even more preferably less than 1.5 MPa, for a residence time of less than 500 minutes, preferably less than 300 minutes and more preferably less than 60 minutes.

When a distillation fraction 28 is used in step h), the weight ratio of the distillation fraction 28 to the heavy fraction 25 obtained at the end of the separation step g) is from 0.01 to 100, preferably from 0.05 to 10.0, more preferably from 0.1 to 5 and even more preferably from 0.1 to 2. When the distillation fraction 28 of the present invention is taken from the process, the fraction 28 may be accumulated for a start-up time to achieve the desired ratio.

Several pieces of equipment may be used to perform this precipitation step h). This embodiment may be performed using an exchanger or a heating oven followed by one or more capacitors in series or parallel, such as horizontal or vertical balloons, optionally with a decanting function to remove a portion of the heaviest solids, and/or a plug flow reactor. Static mixers or stirred and heated tanks, optionally equipped with a jacket capable of temperature regulation, can also be used and can be equipped with a withdrawal device at the bottom to remove a portion of the heaviest solids.

At the end of step h), a hydrocarbon-based fraction 29 is obtained having an enriched content of the existing sediment, which is optionally at least partially mixed with the distillation fraction 28 or with the oxidant used during step h). The mixture is sent to step i) of physical separation of the sediment. Before said fraction 29 is sent to step i), it may be advantageous to carry out an intermediate separation sub-step in order to separate the hydrocarbon-based fraction from at least part of the distillation fraction 28 or the oxidant used during step h). For example, stripping may be performed to remove dissolved oxygen.

Step i) of physically separating the sediment

According to the invention, the process comprises a step i) of physically separating the sediment from the heavy liquid fraction 29 coming from the precipitation step h), so as to obtain, on the one hand, a liquid hydrocarbon-based fraction 31 (optionally as a mixture with the distillation fraction 15 or with the oxidizing agent) and, on the other hand, a sediment fraction 30. The latter fraction 30 is enriched in sediment.

The heavy liquid fraction 29 obtained at the end of the precipitation step h) contains organic sediments of the precipitated asphaltene type, resulting from the hydrocracking and precipitation conditions of the present invention. This heavy liquid fraction 29 may also contain catalyst fines resulting from attrition of the extrudate type catalyst in use in an ebullated bed hydrocracking reactor.

Whereby at least a portion of the heavy liquid fraction 29 coming from the precipitation step h) is subjected to a physical separation of the sediments and catalyst residues by means of a physical separation device selected from filters, separation membranes, beds of filtered solids of organic or inorganic type, electrostatic precipitation, electrostatic filters, centrifugal systems, decantation, centrifugal decanter, extraction via an endless screw. During the physical separation step i) of the sediment and of the catalyst residues, it is possible to use a combination (in series and/or in parallel, and possibly operating sequentially) of a plurality of separation devices of the same type or of different types. One of these solid-liquid separation techniques may require periodic use of a flush hydrocarbon light fraction, which may or may not result from the process, enabling, for example, cleaning of the filter and discharge of sediment.

At the end of step i) of physical separation of the sediment, a liquid hydrocarbon-based fraction 31 is obtained with a low sediment content, in particular with an aged sediment content of less than or equal to 0.1% by weight, which may optionally comprise at least part of the distillation fraction 28 or the oxidizing agent of the invention introduced during step h).

At the end of step i) of separating the sediment, a fraction 30 enriched in sediment is obtained. It may for example comprise a sediment mixed with a rinsing hydrocarbon light fraction which is recycled to clean the physical separation device used in step i).

Optional separation step j)

In the case where the liquid hydrocarbon-based fraction 31 comprises at least a portion of the distillation fraction 28 according to the invention introduced during stage h), this mixture can be introduced in a subsequent stage j), comprising the separation of the distillation fraction 32 from the relevant liquid hydrocarbon-based fraction 33 having a low sediment content, in particular an aged sediment content of less than or equal to 0.1% by weight.

According to one embodiment, a portion of the distillation fraction 28 may be left in the liquid hydrocarbon-based fraction having a low sediment content, so that the viscosity of the mixture is directly that of the desired fuel oil grade.

The liquid hydrocarbon-based fraction 31 or 33 having a low sediment content can advantageously be used as fuel feedstock or fuel, in particular as fuel oil feedstock or fuel oil, in particular as bunker fuel oil feedstock or bunker fuel oil, having an aged sediment content of less than 0.1 wt.%. Advantageously, said liquid hydrocarbon-based fraction 31 or 33 with low sediment content is mixed with one or more fluxing feedstocks selected from the group consisting of light distillates from catalytic cracking, heavy distillates from catalytic cracking, residues from catalytic cracking, kerosene, diesel, vacuum distillates and/or clarified oils.

Examples

The following examples are intended to describe specific embodiments of the present invention, but not to limit the scope thereof.