阅读说明：本技术 包括固定床加氢处理、两次脱沥青操作和沥青的加氢裂化的用于处理重质烃原料的方法 (Process for treating heavy hydrocarbon feedstocks comprising fixed bed hydroprocessing, two deasphalting operations and hydrocracking of the bitumen ) 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：本发明涉及一种生产燃料基础油的方法,该方法包括一系列特定步骤,包括固定床加氢处理步骤,由固定床加氢处理步骤产生的重级分的脱沥青步骤,DAO级分的固定床加氢裂化步骤,沥青级分的沸腾床加氢裂化步骤和由沸腾床加氢裂化步骤产生的重级分的脱沥青步骤。(The present invention relates to a process for producing a fuel base oil, which comprises a series of specific steps, including a fixed bed hydrotreating step, a deasphalting step of a heavy fraction resulting from the fixed bed hydrotreating step, a fixed bed hydrocracking step of a DAO fraction, an ebullated bed hydrocracking step of a pitch fraction, and a deasphalting step of a heavy fraction resulting from the ebullated bed hydrocracking step.)

1. A process for treating a hydrocarbon-based feedstock (1) 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 brought into contact with a hydrotreating catalyst in the presence of hydrogen, allowing an effluent (4) to be obtained,

b) a step of separating the effluent (4) resulting from the hydrotreatment step a) into at least one light fraction (5) and a heavy fraction (7) containing compounds having a boiling point of at least 350 ℃,

c) a step of deasphalting the heavy fraction resulting from the separation step b) by means of a solvent (8) or a mixture of solvents, which allows obtaining a fraction (10) comprising bitumen and a fraction (11) comprising deasphalted oil,

d) a step of hydrocracking at least a portion of fraction 11) resulting from step c), carried out in at least one fixed bed reactor in the presence of a hydrocracking catalyst and hydrogen, allowing an effluent (14) to be obtained,

e) a step e) of separating the effluent resulting from step d) into at least one gaseous fraction (15) and a heavy liquid fraction (16) containing compounds having a boiling point of at least 350 ℃,

f) a step of hydrocracking at least a portion of the fraction (10) resulting from step c) carried out in at least one ebullated-bed reactor in the presence of a hydrocracking catalyst and hydrogen, allowing to obtain an effluent (21),

g) a step of separating the effluent (21) resulting from step f) into at least one gaseous fraction (22) and a heavy liquid fraction (25) containing compounds having a boiling point of at least 350 ℃,

h) a step of deasphalting the heavy liquid fraction (25) resulting from step g) by contacting said fraction (25) with a solvent (28) or a mixture of solvents (28), which allows obtaining a fraction (30) comprising bitumen and a fraction (31) comprising deasphalted oil.

2. The process according to claim 1, wherein a portion of the heavy fraction (25) obtained from 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 (25) obtained from step g) is recycled to the ebullated bed hydrocracking step f).

4. The process according to any one of the preceding claims, wherein step g) uses vacuum distillation and allows obtaining a vacuum distillate fraction (23).

5. The process according to claim 4, wherein a portion of the vacuum distillate fraction (23) is sent to a fixed bed hydrocracking step d).

6. The process according to any one of the preceding claims, wherein at least a portion of the heavy fraction (7) resulting from the separation step b) is sent to the hydrocracking step d).

7. The process according to any one of the preceding claims, wherein at least a portion of the heavy fraction (16) comprising at least 80% of the compounds boiling between 350 and 540 ℃ resulting from the separation step e) is sent to the hydrocracking step d).

8. The process according to any one of the preceding claims, wherein at least a portion of the heavy fraction (25) comprising at least 80% of the compounds boiling between 350 and 540 ℃ is sent to the hydrocracking step d), the heavy fraction resulting from the separation step g) of the effluent of the hydrocracking step f).

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

10. The process according to claim 9, wherein the deasphalting step c) and/or h) is carried out under subcritical conditions with respect to said solvent or solvent mixture.

11. The process according to any one of claims 9 and 10, wherein in step c) and/or h) a part of the solvent is injected into the extraction column at a first point and another part of the solvent is injected into the extraction column at a second point located lower than the first point.

12. The process according to any of the preceding claims, wherein step c) and/or h) 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 resulting from direct distillation, crude oils, topped crude oils, tar sands or derivatives thereof, bitumen shales or derivatives thereof, and hydrocarbon-derived rock oils or derivatives thereof, used alone or as a mixture.

Technical Field

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

General background

The fractions which can be used as bunker fuel or bunker fuel base oils, such as bunker fuel oil or bunker fuel oil base oils, must have a low impurity content, in particular a sulphur content, and must meet the bunker fuel quality requirements described in standard ISO 8217.

SOx Emissions (annex VI of the MARPOL convention of the International maritime organization) are also of concern for the future specification of sulfur and are embodied as suggesting a sulfur content of less than or equal to 0.5% by weight outside the sulfur emission Control zone (ZCES or emulsions Control Areas) and less than or equal to 0.1% by weight in ZCES by the year 2020 and 2025.

In the field of the treatment of heavy hydrocarbon fractions, hydrotreating and hydrocracking processes allow to reduce the impurity content, while allowing to convert the feedstock more or less into lighter products.

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

Another highly restrictive recommendation in standard ISO8217 is that the deposit content after ageing must be less than or equal to 0.1% according to standard ISO 10307-2 (also known as IP 390). This content of deposits after ageing is much more limiting than the content of deposits 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 IP375), there are also deposits which, depending on the conversion conditions, are characterized as potential deposits. These deposits usually occur after physical, chemical and/or thermal treatment.

In processes for treating heavy hydrocarbon fractions, it is known to carry out deasphalting operations. Deasphalting allows to separate an asphaltene-rich fraction from a deasphalted oil fraction (called DAO) with a greatly reduced asphaltene content, promoting its appreciation by catalytic cracking or hydrocracking. For example, patent FR2753983 describes a process for converting a heavy hydrocarbon fraction comprising a fixed bed hydrotreating step followed by a step of deasphalting the vacuum residue obtained after atmospheric distillation and vacuum distillation of the effluent from the hydrotreatment, the DAO being subsequently sent to an ebullated bed hydrotreating step. The problem encountered is the appreciation of the bitumen fraction, which is generally considered to be waste; it is therefore advantageous to convert this fraction into other products of better value or to limit the yield of bitumen. Patent US7214308 describes a conversion process in which the residual feedstock is treated in a deasphalting step, then the DAO fraction is sent to an ebullated bed hydrocracking step, and the pitch fraction is sent to another ebullated bed hydrocracking step. According to this embodiment, the yield of bitumen is high and the product resulting from the ebullated bed hydrocracking step of bitumen is not very purified; for example, the heavy fraction cannot be added to a low sulfur content marine fuel.

The object of the present invention is to overcome the problems of the prior art described above and in particular to provide a process which allows the flexible production of fuel base oils, in particular bunker fuels (marine oils) or bunker base oils (des bases de marine oils), such as bunker fuel oil (des fuel oils) or bunker fuel oil base oil (base des fuel oils), with a low impurity content, in particular a low sulphur content, which meet the bunker fuel quality requirements described in the ISO8217 standard, while reducing the bitumen fraction and better increasing the value thereof to increase the 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) can be adjusted and thus the ratio between light products and heavy products can be adjusted.

The aim of the process according to 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.

The applicant has therefore developed a novel process for producing fuel base oils comprising a series of specific steps, including a fixed bed hydrotreatment step to reduce the impurities, in particular the asphaltene content, of the products resulting from the process, a deasphalting step of the heavy fraction resulting from the fixed bed hydrotreatment step to produce a DAO fraction and an asphaltic fraction, a fixed bed hydrocracking step of the DAO fraction, an ebullated bed hydrocracking step and a deasphalting step of the heavy fraction resulting from the ebullated bed hydrocracking step.

The invention has the following advantages:

flexibility in terms of yield of products produced by conversion of the initial heavy feedstock that can be used as fuel (for example marine fuel or marine fuel base oil, such as marine fuel oil or marine fuel oil base oil), in particular by means of optional recycling of the unconverted fraction produced by the ebullated bed hydrocracking step upstream of this step or upstream of deasphalting;

-a step of precipitation and separation of the heavy fraction deposits resulting from the ebullated bed hydrocracking step of the pitch fraction, which allows obtaining fuel base oils, in particular marine fuel base oils with a reduced content of deposits.

Summary of The Invention

The subject of the present invention is therefore 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 resulting from the hydrotreatment step a) into at least one light fraction and a heavy fraction containing compounds having a boiling point of at least 350 ℃,

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

d) A step of hydrocracking at least a portion of the fraction comprising deasphalted oil obtained in step c), which is carried out in at least one fixed-bed reactor in the presence of a hydrocracking catalyst and hydrogen,

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

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

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

h) the step of deasphalting the heavy fraction resulting from the separation step b) by means of a solvent or solvent mixture allows to obtain a fraction comprising bitumen and solvent or solvent mixture on the one hand and a fraction deasphalted oil comprising on the other hand.

Advantageously, the continuous step according to the invention allows to reduce the content of asphaltenes during the fixed bed hydrotreatment step, thus allowing to reduce the amount of bitumen produced during deasphalting. Furthermore, the fixed bed hydrotreating step allows to reduce the sulfur content and therefore also the sulfur content of the products resulting from the fixed bed hydrocracking step of DAO and of the products resulting from steps downstream of the ebullated bed hydrocracking of the bituminous fraction.

Advantageously, the optional recycling of a portion of the unconverted heavy fraction upstream of deasphalting allows to increase the yield of deasphalted oil DAO and therefore of distillate during fixed bed hydrocracking.

Advantageously, the optional recycling of a portion of the unconverted heavy fraction upstream of the ebullated-bed hydrocracking step of the bituminous fraction allows to increase the yield of lighter products.

Furthermore, the subject of the invention is an optional step j) of separating the liquid hydrocarbon fraction with reduced sediment content obtained in step i) from the distillate fraction or from the oxidizing agent introduced during the sediment precipitation step h).

According to one embodiment, at least a portion of the heavy fraction comprising at least 80% of the compounds boiling between 350 and 540 ℃ resulting from the separation step b) of the effluent of the hydrotreating step a) is sent to the hydrocracking step d).

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

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

According to one embodiment, the solvent used in step c) is a non-polar solvent consisting of a saturated hydrocarbon 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, while another portion of the solvent is injected into the extraction column at a second point lower than the first point.

According to one embodiment, the hydrocarbon-based feedstock is chosen from atmospheric residues, vacuum residues resulting from direct distillation, crude oil, topped crude oil, tar sands or derivatives thereof, bitumen shales or derivatives thereof, and source rock oils (hue de roche me re) or derivatives thereof, used alone or as a mixture.

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

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

Further subjects and advantages of the invention will become apparent from reading the following description of a particular exemplary embodiment of the invention, given by way of non-limiting example, which is made with reference to the accompanying drawings described below.

Brief description of the drawings

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

Fig. 2 is a variant of the embodiment of the process according to the invention shown in fig. 1.

Fig. 3 is a variant of the embodiment of the process according to the invention shown in fig. 1.

A variation of the embodiment is shown in fig. 2 and 3; only the elements that differ from the embodiment of fig. 1 are described below.

Fig. 2 shows a variant of fig. 1 in which the effluent 14 resulting from the fixed bed hydrocracking step d) and the effluent 21 resulting from the ebullated bed hydrocracking step f) are treated in a separation step g) common to both effluents. Optionally, a portion of fraction 23 can be sent via line 24 to fixed bed hydrocracking step d) and/or via line 34 to deasphalting step c) and/or via line 36 to deasphalting step h).

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

Figures 1, 2 and 3 are examples of non-limiting embodiments of the present invention. In the figures only the main steps are shown, but it is understood that all the equipment necessary for the operation (round bottom vessel, pumps, compressors, exchangers, ovens, columns, etc.) is present. Only the main stream containing hydrocarbons is shown, but it is understood that the hydrogen-rich stream (make-up or recycle) may be injected at the inlet of each catalytic bed or reactor or between two catalytic beds or reactors. Methods for purifying and recycling hydrogen well known to those skilled in the art are also used.

The treated feedstock and the different steps of the method according to the invention will now be described in more detail below.

Raw materials

The feedstock 1 treated in the process according to the invention is 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.%, relative to the weight of the feedstock.

Feed 1 has an initial boiling point of at least 340 c and a final boiling point of at least 600 c.

The hydrocarbon-based feedstock 1 may be selected from atmospheric residues, vacuum residues resulting from direct distillation, crude oils, topped crude oils, tar sands or derivatives thereof, bitumen shales or derivatives thereof, and hydrocarbon-derived rock oils or derivatives thereof, used alone or as mixtures. In the present invention, the feedstock to be treated is preferably an atmospheric residue or a vacuum residue, or a mixture of these residues, more preferably a vacuum residue.

The hydrocarbonaceous feedstock treated in the process according to the invention may contain inter alia sulphur-containing impurities. The sulfur content may be at least 0.1 wt.%, at least 0.5 wt.%, preferably at least 1.0 wt.%, more preferably at least 2.0 wt.%, relative to 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 10ppm, preferably at least 30ppm, with respect to the weight of the feedstock.

The hydrocarbon-based feedstock treated in the process may contain, inter alia, Conradson carbon. The conradson carbon content may be at least 2.0 wt.%, preferably at least 5.0 wt.%, relative to the weight of the feedstock.

These starting materials can advantageously be used as such. Alternatively, they may be diluted with co-feed 3. A 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 co-feed 3 may be a hydrocarbon-based fraction or a mixture of lighter hydrocarbon-based fractions, which may preferably be selected from the products obtained from a fluid catalytic cracking (FCC or fluid catalytic cracking) process, in particular light fractions (LCO or light cycle oil), heavy fractions (HCO or heavy cycle oil), decant oil, FCC residues. The co-feed 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. The co-feed 3 may also be a deasphalted oil obtained by deasphalting the residue resulting from atmospheric distillation or vacuum distillation of the crude oil or of the effluent from the conversion process. The co-feedstock 3 may also advantageously be one or more fractions resulting from a process of liquefaction of coal or biomass, aromatic extracts or any other hydrocarbon-based fraction, or a non-petroleum feedstock, such as pyrolysis oil. The heavy hydrocarbonaceous feedstock 1 according to the present invention may represent at least 50%, preferably 70%, more preferably at least 80%, even more preferably at least 90% of the total hydrocarbonaceous feedstock (i.e. the initial heavy hydrocarbonaceous feedstock 1 and co-feedstock 3 as defined above which has been treated by the process according to the present invention).

In some cases, the co-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 co-feed 13 upstream or downstream of the first catalytic bed or upstream or downstream of the subsequent catalytic bed of the fixed bed hydrocracking step d), or to introduce the co-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 those mentioned above for co-feed 3. Very preferably, co-feed 13 comprises vacuum diesel and co-feed 20 comprises a fraction obtained 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 brought into contact with a hydrotreating catalyst in the presence of hydrogen and an effluent 4 is allowed to be obtained.

The term "hydrotreatment", commonly referred to as HDT, is intended to mean a catalytic treatment by introduction of hydrogen which allows to refine, i.e. to significantly reduce the content of metals, sulphur and other impurities of the hydrocarbon-based feedstock, while improving the hydrogen to carbon ratio of the feedstock and converting the feedstock more or less partially into lighter fractions. Hydrotreating includes, in particular, hydrodesulfurization (commonly referred to as HDS) reactions, hydrodenitrogenation (commonly referred to as HDN) reactions and hydrodemetallization (commonly referred to as HDM) reactions, accompanied by hydrogenation, hydrodeoxygenation, hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking or hydrodeasphalting reactions, and conradson carbon reduction.

According to one embodiment of the invention, the hydrotreatment step a) comprises a first Hydrodemetallization (HDM) step a1) carried out in one or more hydrodemetallization zones in a fixed bed and a subsequent second Hydrodesulfurization (HDS) step a2) in one or more fixed bed hydrodesulfurization zones. During the first hydrodemetallization step a1), the feedstock and hydrogen are contacted over a hydrodemetallization catalyst under hydrodemetallization conditions, and then during the second hydrodesulphurization step a2), the effluent from the first hydrodemetallization step a1) 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, switchable reactors (PRS technology, switchable reactor system) are used when the feedstock contains more than 70ppm, even more than 150ppm of metals and/or when the feedstock contains impurities such as iron derivatives, as described in patent FR 2681871. These switchable reactors are usually fixed beds located upstream of the fixed bed HDM section.

According to one embodiment of the invention, at least one reactor of the hydrotreatment step a), preferably a switchable reactor, is equipped with filtration and distribution means, such as those described in patent applications FR3043339 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 that a portion of the other hydroprocessing reactions, especially the HDS reaction, are also carried out. Likewise, 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. It is understood by those skilled in the art that the HDM step begins where the hydrotreating step begins (i.e., where the concentration of metals is at their maximum). It is understood by those skilled in the art that the HDS step ends where the hydrotreating step ends (i.e., where sulfur removal is most difficult). Between the HDM step and the HDS step, the person skilled in the art sometimes defines a transition zone in which all types of hydroprocessing reactions take place.

The hydrotreatment step a) according to the invention is carried out under hydrotreatment conditions. It can advantageously be carried out at a temperature of between 300 ℃ and 450 ℃, preferably between 350 ℃ and 420 ℃, and at an absolute pressure of between 5MPa and 35MPa, preferably between 11MPa and 20 MPa. The temperature is typically adjusted depending on the desired level of hydrotreating and the duration of the target treatment. Most commonly, the space velocity of the hydrocarbon-based feedstock, commonly referred to as VVH, and which is defined as the volumetric flow of the feedstock divided by the total volume of the catalyst, can be at 0.1h ^-1To 5.0h ^-1Preferably 0.1h ^-1To 2.0h ^-1More preferably 0.1h ^-1To 1.0h ^-1Within the range of (1). The amount of hydrogen mixed with the feedstock can be in the range of per cubic meter (m) ³) Liquid raw material 100- ³) Preferably between 200Nm ³/m ³To 2000Nm ³/m ³More preferably 300Nm ³/m ³To 1500Nm ³/m ³In the meantime. Step a) of the hydrotreatment can be carried out industrially in one or more fixed-bed reactors with a descending liquid stream.

The hydrotreating catalyst used is preferably a known catalyst. It may be a particulate catalyst comprising at least one metal or comprising gold having a hydrogenation-dehydrogenation function on a supportCompounds of the genus (oxides, sulfides, etc.). These catalysts may advantageously be catalysts comprising at least one group VIII metal, generally selected from nickel and cobalt, and/or at least one group VIb metal, preferably molybdenum and/or tungsten. For example, nickel comprising from 0.5% to 10.0% by weight, preferably from 1.0% to 5.0% by weight, of nickel (expressed as nickel oxide NiO), and from 1.0% to 30.0% by weight, preferably from 5.0% to 20.0% by weight, of molybdenum (expressed as molybdenum oxide MoO), relative to the total weight of the catalyst, on an inorganic support, may be used ₃) The catalyst of (1). The support may, for example, be selected from the group consisting of alumina, silica-alumina, magnesia, clay and mixtures of at least two of these minerals. Advantageously, the support may comprise further 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 and are 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 ₃The alumina used may be gamma (gamma) or η (e ta) alumina, the catalyst generally being in the form of extrudates, the total content of oxides from the group VIb and VIII metals, relative to the total weight of the catalyst, may be from 5.0% to 40.0% by weight, generally from 7.0% to 30.0% by weight, and the weight ratio, expressed as metal oxide, between the metal(s) of group VIb and the metal(s) of group VIII is generally between 20 and 1, most generally between 10 and 2.

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

In the case of a hydrotreating step comprising an HDM step followed by an HDS step, it is preferable to use a specific catalyst suitable for each step.

Catalysts which can be used in the HDM step are indicated, for example, in the patent documents EP0113297, EP0113284, US5221656, US5827421, US7119045, US5622616 and US 5089463. Preferably, HDM catalysts are used in the switchable reactors.

Catalysts which can be used in the HDS step are indicated, for example, in patent documents EP0113297, EP0113284, US6589908, US4818743 or US 6332976.

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

Prior to the injection of the feedstock 1 in step a), the catalyst used in the process according to the invention is preferably subjected to an in-situ or ex-situ sulfidation treatment.

Separation step b)

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

The term "light fraction" is intended to mean a hydrocarbon fraction in which at least 80% of the compounds have a boiling point below 350 ℃. This light fraction contains fuel base oil.

The term "heavy fraction containing compounds having a boiling point of at least 350 ℃ refers to a hydrocarbon fraction in which at least 50% of the compounds have a boiling point of greater than or equal to 350 ℃ and preferably in which at least 80% of the compounds have a boiling point of 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 hydrocarbon fraction of the naphtha, kerosene and/or diesel type. Preferably, heavy fraction 7 comprises a vacuum distillate fraction and a vacuum residue fraction and/or an atmospheric residue fraction. More preferably, in addition to heavy fraction 7, which contains at least 70% of the vacuum residue fraction with compounds having a boiling point above 540 ℃, a heavy fraction 6 is withdrawn which contains at least 80% of the compounds having a boiling point between 350 and 540 ℃.

The separation step b) can be carried out according to any method and any means 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 different processes that may be operated at different 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 (HPBT) separator, optionally followed by an atmospheric distillation stage and/or a vacuum distillation stage. The effluent 4 resulting from the hydrotreatment step a) is preferably first sent to an HPHT separator, allowing to obtain a light fraction and a heavy fraction mainly containing compounds with a boiling point of at least 350 ℃. HPHT separation is not based on a precise cut point, but on a separation similar to the flash type (according to the english term "flash"). The cut point of the separation is advantageously between 200 ℃ and 400 ℃. The light fraction produced by the HPHT separator may then be partially condensed in the HPBT separator to obtain a hydrogen containing gas fraction and a distillate containing liquid fraction.

Preferably, the heavy fraction produced by the HPHT separator, preferably mixed with the liquid fraction comprising the distillate produced by the HPBT separator, can then be fractionated by atmospheric distillation into at least one atmospheric distillate fraction (preferably containing at least one light hydrocarbon fraction of naphtha, kerosene and/or diesel type) and an atmospheric residue fraction. At least a portion of the atmospheric resid fraction can also be fractionated by vacuum distillation into a vacuum distillate fraction (preferably containing vacuum diesel) and a vacuum resid 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). A part of the vacuum residue fraction and/or the atmospheric residue fraction may also be used directly as a fuel base oil, in particular a fuel oil base oil, e.g. a fuel oil base oil with a low sulphur content. A portion of the vacuum residue fraction and/or the atmospheric residue fraction may also be sent to another conversion process, particularly an FCC process. A portion of vacuum diesel fraction 6 may also be used directly as a fuel base oil, in particular as a fuel base oil with a low sulphur content. A portion of the vacuum diesel fraction may also be sent to another conversion process, in particular an FCC process or a fixed bed hydrocracking process. Preferably, at least a portion, very preferably all, of the vacuum diesel fraction 6 is passed to the fixed bed hydrocracking step d).

The gaseous fraction resulting 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 reactor of the ebullated bed hydrocracking step f). The presence of a separation step b) between the hydrotreatment 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 allows to have three separate hydrogen circuits, one connected to the hydrotreatment of step a), one connected to the hydrocracking of step d) and the other connected to the hydrocracking of step f) and, as required, they can be connected to each other. The hydrogen make-up can be carried out at the location of the hydrotreating step a) and/or at the location of the hydrocracking step d) and/or at the location of the hydrocracking step f). The recycle hydrogen may feed the hydrotreating step a) and/or the hydrocracking step d) and/or the hydrocracking step f). The compressor may optionally be shared with two or three hydrogen circuits. The fact that two or three hydrogen circuits can be connected allows to optimize the hydrogen management and to limit the investment in compressors and/or units for purifying the gaseous effluent. Different 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), comprising hydrocarbons of naphtha, kerosene and/or diesel type, can be upgraded according to methods well known to those skilled in the art. The obtained product may be integrated into the fuel formulation, typically a fuel oil (also referred to as fuel pool) or may be subjected to additional refining steps.

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

The light fraction 5 obtained at the end of step b) can be used at least partially for forming the distillate fraction 28 according to the invention used in the sediment precipitation step h).

Deasphalting step c)

According to the process of the invention, the heavy fraction 7 containing compounds having a boiling point of at least 350 ℃ obtained from the separation step b) is subjected to a deasphalting step c) by means of a solvent or solvent mixture 8, allowing to obtain, on the one hand, a fraction 10 comprising bitumen and, on the other hand, a fraction 11 comprising DAO. It is therefore operated by means of liquid-liquid extraction of at least one hydrocarbon solvent 8.

According to one embodiment of the invention, a small portion of the feedstock 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 conditions which allow to obtain an acceptable DAO 11, preferably with a low asphaltene content, and an acceptable bitumen 10, preferably with a relatively low viscosity and a moderate softening point.

The deasphalting step c) is preferably carried out in a single step by contacting the deasphalted feedstock, i.e. the heavy fraction 7 obtained from step b), optionally accompanied by 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 (i.e. conditions below the critical point) with respect to the solvent or mixture of solvents 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 plates etc.) placed in one or more zones. Preferably, the solvent or solvent mixture 8 according to the invention is introduced into the extraction column in two different horizontal positions. Preferably, the deasphalted feedstock is introduced into the extraction column at only one introduction level, typically as a mixture with at least a portion of the solvent or solvent mixture 8, and typically below the first liquid-liquid contactor zone. Preferably, another portion of the solvent or solvent mixture 8 is injected at a lower level than the deasphalted feedstock, generally below the second liquid-liquid contactor area, above which the deasphalted feedstock is injected.

Step c) is carried out under subcritical conditions for 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 ℃, advantageously at a pressure ranging from 0.1 to 6MPa, preferably from 1 to 6MPa, 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 12/1, preferably from 2/1 to 9/1, expressed in liters/kg. This ratio includes all solvents or solvent mixtures that can 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; bicyclic aromatic hydrocarbons (diamaromatic hydrocarbons) or polycyclic aromatic hydrocarbons (polyaromatic hydrocarbons); cycloalkane-aromatic hydrocarbons such as tetralin or indane; heteroatomic aromatic hydrocarbons (oxygen-containing, nitrogen-containing or sulfur-containing) or any other family of compounds with more polar character than saturated hydrocarbons, such as dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) or Tetrahydrofuran (THF). The polar solvent used in the deasphalting step of the process according to the invention may be an aromatic-rich fraction. The aromatic-rich fraction according to the invention may be, for example, a fraction produced by FCC, such as heavy gasoline or LCO, or a fraction produced by a petrochemical unit or refinery. Mention may also be made of fractions derived from coal, biomass or mixtures of biomass/coal optionally with residual petroleum feedstocks (after thermochemical conversion with or without hydrogen and with or without catalyst). Preferably, the polar solvent used is a pure mono-aromatic hydrocarbon or a mono-aromatic hydrocarbon mixed with an aromatic hydrocarbon.

According to one selective deasphalting embodiment comprising a combination of polar and non-polar solvents, part or all of the polar and non-polar solvents are injected at a first point, while another part of the solvent or of the mixture of polar and non-polar solvents is injected at a second point. According to this embodiment, preferably, a polar solvent that is heavier than the non-polar solvent is injected at the lowest point.

The non-polar solvent used is preferably a solvent consisting of a saturated hydrocarbon comprising a carbon number greater than or equal to 3, preferably from 3 to 5. These solvents are used in pure form or as mixtures (for example, mixtures of light petroleum fractions of the paraffinic and/or naphthenic type or of naphtha type).

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

The combination of the choice of temperature and pressure conditions of the extraction and the choice of the type of solvent 8 in the deasphalting step c) then allows the extraction performance to be adjusted. Due to these specific deasphalting conditions, step c) may allow to precipitate the maximum amount of polar structures of the heavy resins and of the asphaltene type in the bituminous fraction 10, thus allowing to obtain the bituminous component 10 with an improved yield, generally greater than 50%, or even greater than 70%, with respect to the amount of compounds having a boiling point higher than 540 ℃ at the entry of the deasphalting step c). Moreover, the softening point of bitumen is moderate, generally below 90 ℃, or even below 70 ℃; likewise, the viscosity is moderate, typically less than 20000cSt at 100 ℃, or even less than 10000cSt at 100 ℃. A low bitumen viscosity is necessary to ensure its pumpability at high pressure in the ebullated bed hydrocracking step f). The high pitch yield allows more conversion products to be obtained at the outlet of the ebullated bed hydrocracking step f). At the same time, DAO fraction 11 is obtained in moderate yield, generally less than 50%, or even less than 30%, with high purity and containing very little asphaltenes, generally less than 500ppm of C7 asphaltenes, or even less than 300ppm of C7 asphaltenes, with respect to the amount of compounds having a boiling point higher than 540 ℃ when entering deasphalting step C).

At the top of the extraction column or mixer-decanter, preferably above the liquid-liquid contactor region located at the highest position, a fraction comprising DAO 11 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 contactor zone, a fraction 10 comprising bitumen and a portion of the solvent or solvent mixture is recovered.

According to one embodiment, in step c) extraction flux 9(fluxant 9 de soupirage) is injected in order to mix with fraction 10 comprising bitumen in order to more easily remove said fraction. Preferably, no extraction flux 9 is injected.

The fluxing agent used may be any solvent or mixture of solvents that can dissolve or disperse the asphalt. The fluxing agent may be a polar solvent selected from the group consisting of mono-aromatics, preferably benzene, toluene or xylene; bicyclic aromatic hydrocarbons (diamaromatic hydrocarbons) or polycyclic aromatic hydrocarbons (polyaromatic hydrocarbons); cycloalkane-aromatic hydrocarbons such as tetralin or indane; a heteroatom aromatic hydrocarbon; polar solvents having a molecular weight corresponding to a boiling point of, for example, 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 aromatic outer fractions extracted from the oil chain, VGO fractions resulting from the conversion of residual fractions and/or coal and/or biomass. The ratio of the volume of flux to the mass of bitumen is determined to allow easy removal of the mixture.

The solvent or solvent mixture 8 may consist of a make-up and/or recycle portion in the separation step. These make-ups are necessary to compensate for solvent losses in the fraction 10 comprising bitumen and/or in the fraction comprising DAO 11. These losses are small but cannot be avoided because the separation step is by definition imperfect.

The deasphalting step c) comprises an integrated sub-step of separating the fraction comprising DAO and the solvent or solvent mixture. The fraction comprising DAO obtained from the extraction is subjected to a separation sub-step, so that on the one hand DAO 11 can be obtained and on the other hand the solvent or solvent mixture introduced during the deasphalting step c) can be obtained. The recovered solvent or solvent mixture may be recycled to the deasphalting step c).

This integrated separation sub-step, which allows to separate DAO 11 and the solvent or solvent mixture, can use all the necessary 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 base oil, particularly as a fuel base oil having a low sulfur content. A portion of the DAO may also be sent to another conversion process, particularly an FCC process.

The deasphalting step c) comprises a further integrated sub-step of separating the fraction comprising bitumen from the solvent or solvent mixture. The fraction comprising the bitumen resulting from the extraction is subjected to a separation sub-step, so that on the one hand bitumen 10 can be obtained and on the other hand the solvent or solvent mixture introduced during the deasphalting step c) can be obtained. The recovered solvent or solvent mixture may be recycled to 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 base oil, particularly as a fuel base oil having a low sulphur content. A portion of the bitumen may also be sent to another conversion process, particularly a coking process. A portion of the bitumen (asphalte) may also be used as a base for making bitumen (bitumes).

Fixed bed hydrocracking step d)

According to the invention, at the end of the deasphalting step c), at least a portion of the DAO fraction 11 obtained in step c) is sent to a fixed bed hydrocracking step d) and an effluent 14 is allowed to be obtained.

The hydrogen 12 may also be injected upstream of the different catalytic beds constituting the hydrocracking reactor. In parallel with the hydrocracking reactions desired in this step, any type of hydrotreating reaction (HDM, HDS, HDN, etc.) also takes place. Hydrocracking reactions occur that result in the formation of atmospheric distillates, wherein the conversion of vacuum distillates to atmospheric distillates is typically greater than 30%, typically between 30% and 50% for mild hydrocracking and greater than 80% for enhanced hydrocracking. The specific conditions, in particular the temperature conditions and/or the use of one or more specific catalysts, allow the desired hydrocracking reactions to be promoted.

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

The hydrocracking step d) generally comprises two catalytic stages in series, namely an upstream hydrotreating catalytic stage, to limit the deactivation of the downstream hydrocracking catalytic stage. The hydrotreating section is specifically intended to significantly reduce the nitrogen content of the feedstock, nitrogen being an inhibitor of the acid function 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 resulting from the separation step.

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

The hydrotreating catalyst used may be a hydrotreating catalyst consisting of a support of 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 to enable hydrogenation of aromatic compounds and to create an equilibrium between saturated compounds and the corresponding olefins, and an acid phase which allows promoting the hydroisomerization and hydrocracking reactions. The acid function is advantageously composed of a high surface area (typically 100 to 800 m) with surface acidity 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 contributed by one or more metals of group VIII of the periodic table of the elements (such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum), or by a combination of at least one metal of group VIB of the periodic table of the elements (such as molybdenum and tungsten) and at least one non-noble metal of group VIII (such as nickel and cobalt). Preferably, the bifunctional catalyst used comprises at least one metal selected from the group consisting of group VIII and VIB metals, alone or as a mixture, and a support comprising from 10% to 90% by weight of zeolite and from 90% to 10% by weight of inorganic oxide. The group VIB metal used is preferably selected from tungsten and molybdenum, and the group VIII metal is preferably selected from nickel and cobalt. According to another preferred variant, the monofunctional catalyst and the bifunctional catalyst of the alumina, amorphous silica-alumina or zeolite type can be used in a mixture or in successive layers.

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

Optionally, the co-feed 13 may be injected upstream of any catalytic bed of the hydrocracking section d). The co-feed is typically a vacuum distillate, or deasphalted oil, produced by direct distillation or by a conversion process.

Optionally, the heavy fraction 6 obtained from separation step b) and containing at least 80% of the compounds having a boiling point between 350 and 540 ℃ can also be injected upstream of any catalytic bed of 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, the heavy fraction 24 obtained from separation step g) and containing at least 80% of the compounds having a boiling point between 350 and 540 ℃ may also be injected upstream of any catalytic bed of hydrocracking step d).

Optionally, the fixed bed hydrocracking step d) may be carried out according to a mode of step type with recirculation, at least a portion of the heavy fraction 18 being recirculated upstream of the hydrotreating 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-step type mode with recycling, at least a portion of the heavy fraction 18 being recycled upstream of the second hydrocracking catalytic section of step d), so as to increase the overall conversion.

In an embodiment variant, the effluent 14 resulting 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. The effluent is advantageously separated in at least one settling drum (balloon separation) 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 connected to a steam or hydrogen stripping means and one or more distillation columns. The separator may be, for example, a High Pressure High Temperature (HPHT) separator and/or a high pressure low temperature (HPBT) separator.

The gas fraction contains gases, in particular H2, H2S, NH3 and C1-C4 hydrocarbons. After optional cooling, this gas fraction is preferably treated in a hydrogen purification unit to recover hydrogen not consumed during the hydrocracking step d). Said hydrogen purification means, which may be common to the plants that treat the gaseous fractions resulting from the separation of the effluents of the hydrotreatment step a) and the ebullated bed hydrocracking step f), may be washing with amines, membranes, PSA type systems, or a plurality of these means in series.

The purified hydrogen can then advantageously be recycled in the process according to the invention. The hydrogen may be recycled at the inlet and/or at different 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, in addition to the gas-liquid separation or the series of separation means, the second separation step e) comprises at least one atmospheric distillation, wherein the liquid hydrocarbon-based fraction obtained after separation is fractionated by atmospheric distillation into at least one atmospheric distillate fraction (stream not shown in the figure) and at least one desulfurized heavy fraction 16 consisting of unconverted vacuum distillate. The atmospheric distillate fraction may contain fuel base oils (naphtha, kerosene and/or diesel) that can be added commercially, for example, in refineries for the production of motor vehicles and aviation fuels. The kerosene and/or diesel-type fractions can also be used as base oils for use in marine distillate-type cells or as residual-type fuel oils or fluxes in marine fuel cells (according to ISO 8217). The unconverted fraction of the vacuum distillate type can advantageously be upgraded to marine fuels with a sulphur content of less than 0.5% or 0.1%, in particular to base oils in marine distillate type tanks with a sulphur content of less than 0.5% or 0.1%, or to residual fuel oils or fluxes in fuel oil tanks (according to ISO 8217).

Optionally, at least a portion of the unconverted fraction 18 of the 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 unconverted fraction 16 of the vacuum distillate type in order to disperse (reconcentrator) the polycyclic aromatic substances and to limit the deactivation of the hydrocracking catalyst of step d). In order to limit the flushing and thus increase the overall conversion, it may be advantageous to optionally carry out this flushing by sending at least part of unconverted fraction 17 of the depressurized distillate type to the inlet of deasphalting step c), in order to at least partially remove the polycyclic aromatic substances (esp es polyaromatics) in bitumen fraction 10.

Fluidized bed hydrocracking step f)

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

At least a portion of the fraction of bitumen 10 obtained from the deasphalting step c) is therefore 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 flow. The main objective 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 (as a mixture with at least a portion of the bituminous fraction 10 resulting from step c)) at the inlet of the ebullated bed hydrocracking step f), while this portion of the initial heavy hydrocarbon-based feedstock 1 is not treated in the hydrotreating step a) and the deasphalting step c). This embodiment may be similar to the partial bypass of the hydrotreating step a) and the deasphalting step c).

According to one embodiment, co-feed (co-charge)20 may be injected at the inlet of the first ebullated bed reactor or at the inlet of one or more subsequent ebullated bed reactors.

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

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 several ebullated bed reactors, hydrogen may be injected at the inlet of each reactor. The injected hydrogen may 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 typically uses supported catalysts in the form of extrudates, typically about 1 millimeter in diameter or less. The catalyst remains in the reactor and is not discharged with the product except during the stages of catalyst make-up and withdrawal required to maintain catalytic activity. The temperature level may be high to achieve high conversion while minimizing the amount of catalyst used. The catalytic activity can be kept constant by replacing the catalyst on-line. Thus, there is no need to stop the plant to replace the spent catalyst, nor to increase the reaction temperature along the cycle to compensate for deactivation. Moreover, the fact of working under constant operating conditions advantageously allows to obtain constant product yields and quality along the cycle. In this way, the head loss on the reactor remains low and constant, since the catalyst is kept stirred by the considerable liquid circulation.

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

Conventional granular hydrocracking may be usedA chemical catalyst comprising at least one metal or metal-containing compound (oxide, sulfide, etc.) having a hydrogenation-dehydrogenation function on an inorganic support. The catalyst may be a catalyst comprising a group VIII metal, such as nickel and/or cobalt, most typically in combination with at least one group VIB metal, such as molybdenum and/or tungsten. For example, use may be made of a catalyst comprising, on an inorganic support, from 0.5% to 10.0% by weight of nickel relative to the total weight of the catalyst, preferably from 1.0% to 5.0% by weight of nickel (expressed as nickel oxide NiO), from 1.0% to 30.0% by weight of molybdenum relative to the total weight of the catalyst, preferably from 5.0% to 20.0% by weight of molybdenum (expressed as molybdenum oxide MoO) ₃Represented by (a). The support may, for example, be selected 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. Most commonly, an alumina support is used, and is typically an alumina support doped with phosphorus and optionally boron. When phosphoric anhydride P is present ₂O ₅When present, the concentration is typically less than 20 wt%, most typically less than 10 wt%. When boron trioxide B is present ₂O ₃The alumina used is generally gamma (gamma) or η (alpha) alumina the total content of oxides of the metals of groups VI and VIII can be from 5 to 40% by weight, preferably from 7 to 30% by weight, the weight ratio, expressed as metal oxide, between the metal(s) of group VI and the metal(s) of group VIII being between 20-1, preferably between 10-2.

The spent catalyst can be partially replaced by fresh catalyst, usually at regular intervals by taking it off at the bottom of the reactor and introducing fresh or fresh catalyst at the top of the reactor, i.e. for example in a batch (bouff é) or continuous or quasi-continuous manner. The catalyst may also be introduced through the bottom and may be withdrawn through the top of the reactor. For example, fresh catalyst may be introduced daily. The rate of replacement of spent catalyst with fresh catalyst can be, for example, from about 0.05kg to about 10kg per cubic meter of feedstock to the hydrocracking step. This removal and this replacement are carried out using a device which allows continuous operation of the hydrocracking step. The hydrocracking reactor typically contains a recirculation pump which maintains the catalyst in an ebullated bed state by continuously circulating at least a portion of the liquid withdrawn at the top of the reactor and re-injected into the bottom of the reactor. The spent catalyst withdrawn from the reactor may also be sent to a regeneration zone where it contains carbon and sulphur removed before being reinjected into the hydrocracking step f).

The hydrocracking step f) of the process according to the invention may be carried out under H-OIL ® process conditions, for example as described in patent US 6270654B.

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 allows for better quality products and higher yields. Furthermore, hydrocracking in the two reactors allows for 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 0.1MPa and 1.0MPa lower than the first reactor to allow flow of at least a portion of the effluent resulting from the first step without pumping. The different operating conditions in terms of temperature in the two hydrocracking reactors are chosen so that in each reactor the hydrogenation and conversion of the feedstock of the hydrocracking step into the desired products can be controlled.

In the hydrocracking step f) in two sub-steps (f) in two reactors arranged in series ₁) And (f) ₂) In the case of (1), in the first substep f ₁) The effluent obtained at the end can optionally undergo a separation step of light and heavy fractions, and at least a portion, preferably all, of the heavy fraction can be subjected to a second hydrocracking substep f ₂) Is processed. This separation is advantageously carried out in an interstage separator (separateur inter-stage), as described for example in patent US6270654B, and in particular allows to avoid excessive cracking of the light fraction in the second hydrocracking reactor. It is also possible to crack the first hydrocracking run from a lower temperatureSubsteps (f) ₁) The spent catalyst withdrawn from the reactor of (f) is wholly or partly transferred directly to a second substep (f) operating at a higher temperature ₂) Or will be from the second substep (f) ₂) The spent catalyst withdrawn from the reactor(s) in whole or in part is directly transferred to the first substep (f) ₁) In the reactor (2). This cascade system is described, for example, in patent US 4816841B.

In the case of large throughputs, the hydrocracking step can also be carried out in parallel using a plurality of (usually two) reactors. Thus, the hydrocracking step may comprise a plurality of steps in series, optionally separated by interstage separators, each stage consisting of one or more reactors in parallel.

Separation step g) of the effluent of the ebullated bed hydrocracking

According to the invention, the process also comprises a step g) of separating the effluent 21 resulting 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 the hydrocracking step f) comprises at least one heavy liquid fraction 25 and a gas-containing gaseous fraction 22, in particular H ₂，H ₂S，NH ₃And C ₁-C ₄Hydrocarbons (i.e., containing 1 to 4 carbon atoms). The heavy liquid fraction is a hydrocarbon-based liquid fraction containing compounds having a boiling point of at least 350 ℃, in particular a hydrocarbon-based liquid fraction wherein at least 50% of the compounds have a boiling point of greater than or equal to 350 ℃, preferably wherein at least 80% of the compounds have a boiling point of greater than or equal to 350 ℃.

The gas 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, optionally connected to a steam or hydrogen stripping means and one or more distillation columns, which can be operated at different pressures and temperatures. The effluent 21 obtained at the end of the 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 for example be High Pressure High Temperature (HPHT) separators and/or high pressure low temperature (HPBT) separators.

After optional cooling, this gas fraction 22 is preferably treated in a hydrogen purification unit to recover hydrogen not consumed during the hydrocracking reaction. The hydrogen purification means, which may be common with the means of treating the gaseous fraction resulting from the separation of the effluents of the hydrotreating step a) and the fixed bed hydrocracking step d), may be amine washing, membranes, PSA type systems or a plurality of these means arranged in series.

The purified hydrogen may then advantageously be recycled in the process according to the invention. The hydrogen may be recycled at the inlet and/or at different 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 achieve the desired pressure when entering 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, obtaining at least one atmospheric distillate fraction and at least one atmospheric residue fraction. The atmospheric distillate fraction may contain fuel base oils (naphtha, kerosene and/or diesel), which are commercially added either directly or after an optional hydrotreatment step (for example in a refinery for fuel production in the automotive and aeronautical fields). Naphtha is also added value in petrochemistry.

The separation step g) of the process according to the 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 obtain at least one vacuum distillate 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 into at least one atmospheric distillate fraction and at least one atmospheric residue fraction by means of atmospheric distillation, and then a vacuum distillation, wherein the atmospheric residue fraction obtained after the atmospheric distillation is fractionated into at least one vacuum distillate fraction and at least one vacuum residue fraction by means of vacuum distillation. The vacuum distillate fraction typically contains a vacuum diesel type fraction.

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

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

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

Deasphalting step h)

According to the process of the invention, the heavy liquid fraction 25 containing compounds having a boiling point of at least 350 ℃ obtained from the separation step g) is subjected to a deasphalting step h) using a solvent or solvent mixture 28, allowing to obtain on the one hand a fraction 30 comprising bitumen and on the other hand a fraction 31 comprising DAO. This is therefore a liquid-liquid extraction operation by means of at least one hydrocarbon-based solvent 28.

The deasphalting step h) is preferably carried out under conditions which allow to obtain a qualified DAO fraction 31, preferably with a low asphaltene content, and a qualified bitumen 30, preferably with a rather low viscosity and a moderate softening point.

The deasphalting step h) is preferably carried out in a single step by contacting the deasphalted feedstock (i.e. the heavy fraction 25 resulting from step g) with a solvent or solvent mixture 28 containing hydrocarbons, so as to obtain a fraction 30 comprising bitumen and a fraction 31 comprising DAO, step h) advantageously being carried out under subcritical conditions (i.e. conditions below the critical point) with respect to the solvent or solvent mixture 28 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 h) can be carried out in an extraction column or extractor, or in a mixer-decanter. Step h) is preferably carried out in an extraction column comprising liquid-liquid contactors (packing elements and/or plates etc.) placed in one or more zones. Preferably, the solvent or solvent mixture 28 according to the invention is introduced into the extraction column in two different horizontal positions. Preferably, the deasphalted feedstock is introduced into the extraction column at only one introduction level, typically mixed with at least a portion of the solvent or solvent mixture 28 and typically below the first liquid-liquid contactor zone. Preferably, another portion of solvent or solvent mixture 28 is injected at a lower level than the deasphalted feedstock, generally below the second zone of the liquid-liquid contactor, above which the deasphalted feedstock is injected.

Step h) is carried out under subcritical conditions for the solvent or solvent mixture 28. Step h) 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 at a pressure advantageously ranging from 0.1 to 6MPa, preferably from 1 to 6MPa, more preferably from 2 to 5 MPa.

The ratio of the volume of solvent or solvent mixture 28 to the mass of the heavy fraction 25 obtained from step g) 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 can 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; bicyclic aromatic hydrocarbons (diamaromatic hydrocarbons) or polycyclic aromatic hydrocarbons (polyaromatic hydrocarbons); cycloalkane-aromatic hydrocarbons such as tetralin or indane; heteroatomic aromatic hydrocarbons (oxygen-containing, nitrogen-containing or sulfur-containing) or any other family of compounds with a polarity higher than that of saturated hydrocarbons, such as dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) or Tetrahydrofuran (THF). The polar solvent used in the deasphalting step of the process according to the invention may be an aromatic-rich fraction. The aromatics-rich fraction according to the invention may be, for example, a fraction produced by FCC, such as heavy gasoline or LCO, or a fraction produced by a petrochemical unit or refinery. Mention may also be made of fractions derived from coal, biomass or biomass/coal mixtures, optionally together with residual petroleum feedstocks after thermochemical conversion with or without hydrogen, with or without catalysts. Preferably, the polar solvent used is a pure mono-aromatic hydrocarbon or a mono-aromatic hydrocarbon 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 and another portion of the solvent or said mixture of polar and non-polar solvents is injected at a second point. According to this embodiment, preferably, a polar solvent that is heavier than the non-polar solvent is injected at the lowest point.

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

Preferably, the solvent 28 used in step h) is a non-polar solvent consisting of at least 80% by volume of saturated hydrocarbons comprising a carbon number greater than or equal to 3, preferably between 3 and 5, in order to obtain a DAO fraction 31 with high yield, and a relatively low viscosity bitumen, in order to facilitate the pumping and appreciation of the bitumen fraction 30. The pitch fraction 30 can also be used directly as a fuel base oil, in particular as a fuel base oil with a low sulphur content. A portion of the pitch 30 may also be sent to another conversion process, particularly a coking process. A portion of bitumen 30 may also be used as a base for making bitumen.

The choice of the temperature and pressure conditions of the extraction in combination with the choice of the kind of solvent 28 in the deasphalting step h) allows to adjust the extraction performance. Step h) may allow, thanks to these particular deasphalting conditions, the maximum amount of polar structures of the heavy resins and of the asphaltene type to be precipitated from the bituminous fraction 30, thus allowing obtaining the bituminous fraction 30 with an improved yield, generally greater than 40%, or even greater than 45%, with respect to the amount of compounds having a boiling point higher than 540 ℃ at the entry of the deasphalting step h). Furthermore, the softening point of the bitumen is between 50 and 220 ℃, preferably between 70 and 160 ℃; likewise, the viscosity is typically less than 30000cSt at 200 ℃, or even less than 10000cSt at 200 ℃. At the same time, the DAO fraction 31 is obtained in moderate yield, generally greater than 40%, even greater than 45%, with respect to the amount of compounds having a boiling point higher than 540 ℃ when entering the deasphalting step g). Fraction 31 contains a small amount of asphaltenes, typically less than 1000ppm of C7 asphaltenes, or even less than 500ppm of C7 asphaltenes.

A fraction comprising DAO 31 and a portion of the solvent or solvent mixture is recovered at the top of the extraction column or mixer-decanter, preferably above the liquid-liquid contactor region located at the uppermost position.

A fraction 30 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 contactor zone.

According to one embodiment, in step h) extraction flux 29 is injected in order to mix with fraction 30 comprising bitumen in order to more easily remove said fraction. Preferably, no extraction flux 29 is injected.

The fluxing agent used may be any solvent or mixture of solvents that can dissolve or disperse the asphalt. The fluxing agent may be a polar solvent selected from the group consisting of mono-aromatics, preferably benzene, toluene or xylene; bicyclic aromatic hydrocarbons (diamaromatic hydrocarbons) or polycyclic aromatic hydrocarbons (polyaromatic hydrocarbons); cycloalkane-aromatic hydrocarbons such as tetralin or indane; a heteroatom aromatic hydrocarbon; polar solvents having a molecular weight corresponding to a boiling point of, for example, 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 aromatic outer fractions extracted from the oil chain (coupe extra-aromatic), VGO fractions resulting from the conversion of residual fractions and/or coal and/or biomass. The ratio of flux volume to pitch mass is determined so that the mixture is easily removed.

The solvent or solvent mixture 28 may consist of a portion that is replenished and/or recycled during the separation step. These make-ups are necessary to compensate for solvent losses in the fraction 30 comprising bitumen and/or in the fraction comprising DAO 31. These losses are small but cannot be avoided because the separation step is by definition imperfect.

The deasphalting step h) comprises an integrated sub-step of separating the fraction comprising DAO 31 and the solvent or solvent mixture. The fraction obtained from the extraction and comprising DAO 31 is subjected to a separation sub-step, so that on the one hand DAO 31 can be obtained and on the other hand the solvent or solvent mixture introduced during the deasphalting step h) can be obtained. The recovered solvent or solvent mixture may be recycled to the deasphalting step h).

Such an integrated separation sub-step, which allows to separate the DAO 31 and the solvent or solvent mixture, can use all the necessary 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 31 is sent to a fixed bed hydrocracking step d). Optionally, a portion of the DAO may also be used directly as a fuel base oil, particularly as a fuel base oil having a low sulfur content. Part of the DAO may also be sent to another conversion process, in particular to the FCC process.

The deasphalting step h) comprises a further integrated sub-step of separating the fraction comprising bitumen from the solvent or solvent mixture. The fraction comprising bitumen from the extraction is subjected to a separation sub-step, so that on the one hand bitumen 30 can be obtained and on the other hand the solvent or solvent mixture introduced during the deasphalting step h) can be obtained. The recovered solvent or solvent mixture may be recycled to the deasphalting step h).

The bitumen 30 may be used directly as a fuel base oil or fuel oil crude, particularly as a fuel oil base stock having a low sulphur content. A portion of the bitumen may also be sent to another conversion process, particularly a coking process. A portion of the bitumen may also be used as a base for making bitumen.