JP2004510875A - Method for producing diesel by medium pressure hydrocracking - Google Patents

Abstract

An intermediate pressure hydrocracking method and apparatus for producing very high quality diesel in high yield.
The hydrogenolysis is above 70 bar, at a partial pressure of hydrogen gas of at most 100 bar, at a temperature of at least 320 ° C., a H ₂ / feed volume ratio of at least 200 Nl / Nl and 0.15 to 7 h. Flow performed at a space velocity per hour of ^-1 . The process is carried out at a conversion of at least 80% by volume and the liquid effluent obtained by hydrocracking is distilled to separate diesel.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a medium-pressure hydrocracking process for producing high-yield, very high-quality diesel (fuel for diesel engines is referred to simply as "diesel" throughout the specification).
[0002]
The invention also relates to a method comprising said hydrocracking method and a catalytic cracking method, and to an apparatus used to carry out said method.
[0003]
[Prior art]
The petroleum refinery must find a refinery design that is expected to take effect in Europe in 2005 and that can adapt to stricter fuel quality regulations. The maximum sulfur content in diesel will be at most 50 ppm. The 95% distillation point for diesel (ASTM D-86) (now 360 ° C.) is likely to be, for example, 10 ° C. lower, which means a 5% reduction in the amount of diesel now produced for refineries. It is also anticipated that the current capacity of polyaromatic compounds will be halved from the current 11% by weight. The cetane number will also rise above 51, for example from the current value of 51 to 52.
[0004]
At the same time, demand for diesel is constantly increasing, and demand is expected to increase by about 20% over the next decade.
[0005]
Distilling crude oil is not enough to cover diesel production. Diesel is currently produced by high-pressure hydrocracking processes (generally at least 120 bar hydrogen gas partial pressure) and has a T ₉₅ Processing heavy raw materials, which are raw materials with temperature. Where T ₉₅ Is the temperature at which 95% by volume is obtained by simulated distillation (ASTM-D2887). Heavy compounds break down into lighter compounds, some of which go into the middle cuts of hydrocracking distillation (diesel and kerosene). Such high pressure methods are customary.
[0006]
Configuration of the Invention
To meet the new standards, diesel from crude distillation must be subjected to strong hydrodesulfurization. Moreover, high-pressure hydrocracking is a costly solution. Therefore, more advantageous solutions have been sought that can also be incorporated into existing equipment to optimize the use of existing refinery resources.
[0007]
The method disclosed in this application can directly produce diesel that meets the 2005 specification from relatively light feeds under conditions more economical than those used in high pressure hydrocracking. A working hydrocracking method (partial pressure of hydrogen gas above 70 bar and at most 100 bar).
[0008]
More precisely, the present invention relates to a process for producing a diesel having a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and a cetane number of more than 51, said process comprising the steps of from 250 ° C. to 400 ° C. T in the range ₅ Temperature and T at most 470 ° C ₉₅ Treating a hydrocarbon feed having a temperature, the method comprises at least 200 Nl / Nl of H ₂ / Raw material volume ratio and 0.15-7h ^-1 Comprises a hydrotreatment with hydrocracking at a temperature of at least 320 ° C. under a hydrogen gas partial pressure of 70 bar or more and at most 100 bar at a space velocity per hour, and the method comprises: The liquid effluent, which is carried out at a conversion of 80% and obtained by hydrocracking, is distilled to separate diesel. Desirably, the distillation bottoms are recycled to the process after purging.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Raw materials, hydroprocessing and hydrocracking
The raw material treated by this method has a T in the range of 250 ° C to 400 ° C, preferably in the range of 280 ° C to 370 ° C. ₅ Have a point. T ₅ The point represents the temperature at which 5% by volume is obtained by simulated distillation (ASTM-D2887).
[0010]
In general, the raw material has a T in the range of 320-400 ° C, or 320-370 ° C. ₅ Have a point. Very advantageously, these feedstocks are subjected to a diesel fraction, for example heavy diesel from atmospheric crude oil distillation (typically a T ₅ With a point) can be added. This heavy diesel fraction can also be obtained directly in atmospheric residue.
[0011]
This procedure (adding diesel) is particularly advantageous. It is the heavy part of the diesel fraction (the most difficult to hydrotreat, containing nitrogen- and sulfur-containing compounds) that is treated by hydrotreatment, followed by medium-pressure hydrocracking Make it possible. From that point on, the remaining diesel cut can be processed using conventional hydroprocessing, which does not require expensive investment.
[0012]
Further, by treating the heavy diesel portion in the process of the present invention, the heavy fraction is hydrodesulfurized, while at the same time its quality is improved (higher than the cetane number obtained by strong hydrotreating alone). Cetane number).
[0013]
The raw materials that can be used also have a T of at most 470 ° C, preferably 450 ° C, more preferably in the range of 390-430 ° C. ₉₅ With temperature. T ₉₅ Represents the 95% point temperature obtained by simulated distillation (ASTM-D2887).
[0014]
Feedstocks that may be mentioned include light vacuum distillates, light fractions of conventional vacuum gas oil (VGO) (eg half the lighter), heavy atmospheric gas oil (HGO), such as from crude oil distillation, or FCC (Catalytic cracking) A mixture of the above-mentioned raw materials or a mixture of at least one diesel fraction and the above-mentioned raw materials discharged from an apparatus.
[0015]
The sulfur content of the treated hydrocarbon feed is generally between 0.2% and 4% by weight, and the nitrogen content is between 100 and 3500 ppm by weight. Thus, they have an organic nitrogen content (i.e., nitrogen contained in organic molecules) of less than 80 ppm, or preferably less than 50 ppm, more preferably less than 10 ppm, and an organic sulfur content (i.e., contained in organic molecules). In order to reduce the amount of sulfur present to less than 200 ppm, preferably less than 50 ppm, it is generally hydrotreated before hydrocracking. These hydrotreated raw materials (clean raw materials) can then be subjected to hydrocracking.
[0016]
Generally, hydrotreating conditions are:
A pressure of 5 to 25 MPa, preferably above 70 bar, with a hydrogen gas partial pressure of 100 bar, preferably at least 80 bar or at least 85 bar;
A temperature of at least 320 ° C, generally at least 350 ° C and at most 450 ° C, usually at most 430 ° C;
H of at least 100 Nl / l, usually between 100 and 2000 Nl / l, or 300-2000 Nl / l ₂ / Raw material volume ratio,
・ 0.1-10h ^-1 , Preferably 0.15-7 h ^-1 , Advantageously 0.05-4 h ^-1 Space velocity per hour,
It is.
[0017]
The conversion achieved in the hydrotreatment is generally at least 10% by volume, with less than 40% of the product boiling below 350 ° C.
[0018]
The hydrotreating may be carried out in the hydrocracking reactor and in the direction of the feed stream, at least in one bed (bed) before the first hydrocracking catalyst bed, or independently in front of the hydrocracking reactor. In the reactor. There may or may not be an intermediate separation of the gas regenerated by the hydrotreatment. A first mode without intermediate separation (same reactor) is preferred. The method also includes an implementation step in which the hydrotreating is performed in a refinery far upstream of the hydrocracking step. Intermediate processing can also be performed.
[0019]
At least a portion of the clean raw materials are subject to the following operating conditions:
Hydrogen gas partial pressure of 70 bar or more, at most 100 bar, preferably at least 80 bar or at least 85 bar;
A temperature of at least 320 ° C, generally at least 350 ° C, at most 450 ° C, usually at most 430 ° C;
H of at least 200 Nl / Nl, usually in the range of 300 to 2000 Nl / Nl ₂ / Raw material volume ratio,
・ Space velocity per hour 0.15-7h ^-1 , Preferably 0.05 to 4 hours ^-1 , In the presence of hydrogen under at least one hydrocracking catalyst.
[0020]
The method can function with or without recycling of the hydrocracked resid distillation residue (unconverted fraction). If there is a recycle, for example if it is separated from the hydrotreating process, the recycle is directed to the hydrocracking reactor or the reaction in which the hydrotreating and hydrocracking are performed It is made for the ingredients that go into the vessel.
[0021]
Under these conditions, for the entire process, the conversion of the product boiling below 350 ° C. is at least 80% by volume, more usually at least 90% by volume, or at least 95% by volume. .
[0022]
Hydroprocessing catalyst
Conventional catalysts can be used, which include at least one amorphous support and at least one hydrodehydrogenation element (generally at least one element from Group VIB and a non-noble metal from Group VIII). And at least one element from Group VIB and at least one non-noble metal element from Group VIII).
[0023]
Very advantageously, the hydrotreating catalyst comprises at least one matrix, at least one hydrodehydrogenation element selected from the group made by elements of groups VIB and VIII of the periodic table, optionally At least one promoter element deposited on the catalyst and selected from the group consisting of phosphorus, boron and silicon, optionally one element from Group VIIA (desirably chlorine, fluorine), and optionally one from Group VIIB; It contains one element (preferably manganese), as well as one element from group VB (preferably niobium).
[0024]
Generally, hydroprocessing catalysts include:
5% to 40% by weight of at least one element from group VIB and non-noble metal group VIII (% oxide);
0-20%, preferably 0.1-20%, of at least one promoter selected from phosphorus, boron, silicon (% oxide), advantageously boron and / or silicon, optionally The presence of phosphorus,
0-20% of at least one Group VIIB element (eg manganese);
0-20% of at least one group VIIA element (eg fluorine, chlorine);
0-60% of at least one group VB element (eg niobium);
0.1 to 95% of at least one matrix (preferably alumina).
[0025]
Desirably, the catalyst comprises boron and / or silicon as promoter elements, optionally with additional phosphorus as another promoter element. The boron, silicon and phosphorus content is between 0.1 and 20%, preferably between 0.1 and 15%, more advantageously between 0.1 and 10%.
[0026]
Non-limiting examples of matrices that can be used alone or as a mixture include alumina, halogenated alumina, silica, silica-alumina, clay (eg, natural clay such as kaolin or bentonite), magnesia, titanium oxide, boron oxide , Zirconia, aluminum phosphate, titanium phosphate, zirconium phosphate, charcoal, and aluminate. A matrix, preferably comprising alumina, more preferably aluminas, such as gamma alumina, is used in a manner known to those skilled in the art.
[0027]
The hydrodehydrogenation function is provided by one metal or a compound of one metal, preferably selected from the non-noble metals Group VIII and VI, preferably selected from molybdenum, tungsten, nickel and cobalt. You. Desirably, it is provided by a combination of at least one element from Group VIII (Ni, Co) and at least one element from Group VIB (Mo, W).
[0028]
The catalyst may advantageously comprise phosphorus. In the prior art, this compound is known to have two advantages to hydrotreating catalysts: particularly easy to prepare when injecting nickel and molybdenum solutions, and to provide better hydrogenation activity. I have.
[0029]
In preferred catalysts, the total concentration of metal oxides from Groups VI and VIII ranges from 5% to 40% by weight, desirably from 7% to 30% by weight, and the Group VIB metal (or metals). And the weight ratio expressed as the ratio of the metal oxide between the Group VII metals (metals) is preferably in the range of 20 to 1.25, more preferably 10 to 2. Phosphorus pentoxide P ₂ 0 ₅ Is less than 15% by weight, preferably 10% by weight.
[0030]
More preferred hydrotreating catalysts comprising boron and / or silicon (desirably boron and silicon) generally comprise at least one metal selected from the following group as a percentage by weight, based on the total catalyst weight, in the following amounts: Only include:
3% to 60%, preferably 3% to 45%, more preferably 3% to 30% of at least one Group VIB metal,
And optionally,
0-30%, preferably 0-25%, more preferably 0-20%, optionally at least one Group VIII metal.
[0031]
The catalyst further comprises at least one support selected from the following groups in the following amounts:
0 to 99%, advantageously 0.1% to 99%, preferably 10% to 98%, more preferably 15% to 95%, of at least one amorphous or low crystallinity Matrix.
[0032]
Said catalyst is characterized in that it further comprises:
0.1% to 20%, preferably 0.1% to 15%, more preferably 0.1% to 10% boron, and / or 0.1% to 20%, preferably 0.1% to 15%, more preferably 0.1% to 10% silicon,
And, optionally:
0-20%, preferably 0.1% -15%, more preferably 0.1% -10% phosphorus,
And again desirably,
0 to 20%, preferably 0.1% to 15%, more preferably 0.1% to 10% by weight of at least one element selected from group VIIA, preferably fluorine.
[0033]
In general, formulations having the following atomic ratios are preferred:
A Group VIII metal / Group VIB metal atomic ratio in the range of 0-1;
A B / VIB metal atom ratio in the range of 0.01 to 3;
A Si / VIB group metal atomic ratio in the range of 0.01-1.5,
A P / VIB group metal atomic ratio in the range of 0.01-1;
A Group VIIA element / Group VIB metal atom ratio in the range of 0.01 to 2.
[0034]
Such catalysts have a higher activity for hydrogenating aromatic hydrocarbons and for hydrodenitrogenation and hydrodesulfurization than catalyst formulations without boron and / or silicon, Moreover, it has a higher activity and selectivity for hydrocracking than known catalyst formulations. Catalysts containing boron and silicon are particularly advantageous. While not wishing to be bound by any particular theory, it is believed that the particularly high catalytic activity of boron and silicon is due to the enhanced acidity of the catalyst due to the complex presence of boron and silicon in the matrix. Provides both improvements in hydrogenation, hydrodesulfurization and hydrodenitrogenation properties, as well as improved hydrocracking activity, as compared to catalysts commonly used in hydrorefining and hydroconversion reactions.
[0035]
Preferred catalysts are NiMo and / or NiW on alumina type catalysts and NiMo on alumina type catalysts doped with at least one element selected from the group consisting of phosphorus, boron, silicon and fluorine. And / or on silica-alumina, or silica-alumina-titanium oxide, doped or undoped with NiW or at least one element selected from the group consisting of phosphorus, boron, fluorine and silicon. NiMo and / or NiW type catalysts.
[0036]
Further particularly advantageous catalysts (particularly with improved activity) for hydrotreating include the partially amorphous Y zeolites described in the Hydrocracking Catalysts section below.
[0037]
Prior to the injection of the feed, the catalysts used in the process of the present invention desirably undergo a sulfidation treatment to at least partially convert the metal species to sulfide before they come into contact with the feed to be treated. Can be This sulfidation activation treatment is well known to those skilled in the art and can be performed in-situ, ie, in a reactor, or ex-situ, using any method described in the literature. And can be accomplished.
[0038]
Conventional vulcanization processes well known to those skilled in the art include hydrogen sulfide (pure or, for example, in a stream of hydrogen / hydrogen sulfide mixture), in the range of 150C to 800C, preferably 250C to 600C. And generally in a through-bed (cross-bed) reaction zone.
[0039]
Hydrocracking catalyst
Preferred catalysts include at least one Y zeolite, at least one matrix and at least one hydrodehydrogenator. Optionally, it also comprises at least one element selected from boron, phosphorus and silicon, at least one group VIIA element (eg chlorine, fluorine), at least one VIIB element (eg manganese) and at least one element A VB group element (eg, niobium) can be included.
[0040]
The catalyst comprises at least one porous, ie, low crystallinity, mineral oxide type matrix. Non-limiting examples which may be mentioned are alumina, silica, silica-alumina, aluminates, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide and clay, used alone or as a mixture. .
[0041]
The hydrodehydrogenation function generally involves at least one element from group VIB of the periodic table (eg, molybdenum and / or tungsten) and / or at least one non-noble metal element from group VIII (eg, cobalt and And / or nickel). Preferred catalysts essentially comprise at least one Group VI metal and / or at least one non-noble Group VIII metal, Y zeolite and alumina. More preferred catalysts include essentially nickel, molybdenum, Y zeolite and alumina.
[0042]
The catalyst optionally contains at least one element selected from the group consisting of boron, silicon and phosphorus. Advantageously, the catalyst optionally comprises at least one element from group VIIA, desirably chlorine or fluorine, optionally at least one element from group VIIB (eg manganese) and optionally at least one element from group VB. Contains one type of element (eg, niobium).
[0043]
The boron, silicon and / or phosphorus can be in the matrix or zeolite or, preferably, can be deposited on the catalyst and thus be mainly on the matrix. Preferred catalysts include B and / or Si as promoter elements, and are desirably deposited in addition to the phosphorus promoter. The amount introduced is 0.1 to 20% by weight of the catalyst, calculated as oxides.
[0044]
The introduced elements, especially silicon, are mainly on the matrix of the carrier, but are not found in Casting microprobes (distribution profiles of various elements), such as transmission electron microscopy combined with X-ray analysis of the catalyst components. Characterized by various techniques or by using electron microprobes to create a map of the elements present in the catalyst.
[0045]
Generally, preferred hydrocracking catalysts advantageously include
0.1-80% by weight Y zeolite,
0.1 to 40% by weight of at least one element from Group VIB and Group VIII (% oxide);
0.1 to 99.8% by weight of matrix (% oxide),
0-20% by weight, preferably 0.1-20%, of at least one element (% oxide) selected from the group made by P, B, Si;
0-20%, preferably 0.1-20% by weight, of at least one Group VIIA element,
0-20%, preferably 0.1-20% by weight, of at least one group VIIB element,
0-60%, preferably 0.1-60% by weight, of at least one VB element,
including.
[0046]
For silicon, the range of 0-20% only includes added silicon and does not include silicon in the zeolite.
[0047]
The zeolite can optionally be a metal element such as a metal from the rare earth series, especially lanthanum and cerium, or a noble or non-noble metal element of Group VIII, such as platinum, palladium, ruthenium, rhodium, iridium, iron, and manganese, Doped with other metals such as zinc, magnesium.
[0048]
Various Y zeolites are used.
[0049]
Particularly advantageous HY acidic zeolites are characterized by various specifications:
Total SiO in the range of about 6-70, preferably in the range of about 12-50 ₂ / Al ₂ O ₃ Molar ratio, sodium content less than 0.15% by weight (measured on zeolite calcined at 1100 ° C.), 24.58 × 10 ^-10 m-24.24 × 10 ^-10 m, desirably 24.38 × 10 ^-10 m-24.26 × 10 ^-10 lattice parameters in the range of m, sodium-take-up capacity of CNa of about 0.85 or more (as grams of Na for 100 g of neutralized and then calcined modified zeolite), about 400 m ² / G or more, desirably 550 m ² / G specific surface area (measured using the BET method), water vapor absorption volume at 25 ° C. for a gas partial pressure of 2.6 Torr (ie 34.6 MPa) of about 6% or more. Further, advantageously, the zeolite has a range of 5% to 45%, preferably 5% to 40%, of the total pore volume of the zeolite in a range of 20 × 10 5 ^-10 m ~ 80 × 10 ^-10 m and a range of 5% to 45%, preferably 5% to 40%, of the total pore volume of the zeolite is 80 × 10 ^-10 m or more, generally 1000 × 10 ^-10 It has a pore distribution (measured by physical adsorption of nitrogen) contained in pores having a diameter of less than m. The remainder of the pore volume is 20 × 10 ^-10 contained within pores having a diameter of less than m.
[0050]
Preferred catalysts using this type of zeolite include a matrix and a lattice constant ranging from 2.424 nm to 2.455 nm, desirably ranging from 2.426 nm to 2.438 nm; ₂ / Al ₂ O ₃ Molar ratio, atomic ratio (n × M ^{n +} ) / Amount of alkaline earth metal or alkali metal cation and / or rare earth cation such that Al is less than 0.8, preferably less than 0.5 or 0.1, 400 m ² / G or more, preferably 550 m ² / G, 0.2% P / P of not less than 6% by specific surface area and weight measured by BET method ₀ At least one dealuminated Y zeolite having a water adsorption capacity at 25 ° C. relative to the value, the catalyst also comprising at least one hydrodehydrogenated metal and silicon deposited on the catalyst. Including.
[0051]
In an advantageous implementation of the invention, a catalyst comprising a partially amorphous Y zeolite is used for hydrocracking.
[0052]
The term “partially amorphous Y zeolite”
I) peak intensity less than 0.40, desirably less than about 0.30;
Ii) less than about 60%, desirably less than about 50% crystalline moieties (as measured by X-ray gland diffraction and compared to a standard Y zeolite in sodium form (Na));
Means a solid having
[0053]
Desirably, the partially amorphous Y zeolite, the solid forming part of the composition of the catalyst of the present invention, has at least one (preferably all) of the following properties:
Iii) a total Si / Al ratio of 15 or more, preferably more than 20 and less than 150;
Iv) Frame Si / Al larger or equal to total Si / Al ^IV ,
V) a pore volume of at least 0.20 ml / g of a solid in which the portion of the solid ranging from 8% to 50% is composed of pores having a diameter of at least 5 nm (nanometers) or 50 °,
・ Vi) 210-800m ² / G, desirably 250 to 750 m ² / G, preferably 300-600 m ² / G specific surface area.
[0054]
The peak intensity and the crystalline portion are measured by X-ray diffraction using a procedure derived from the method of ASTM D3906-97 "Measurement of relative X-ray diffraction intensity of faujasite-type-containing material". A comparison with this method must be made with regard to the general conditions of application of this procedure, in particular the preparation of samples and standards.
[0055]
Electron diffractograms consist essentially of characteristic lines emanating from the sample and the background crystalline portion, caused by scattering from the amorphous or microcrystalline portion of the sample (weak diffusion signals are It may be related to air, sample carrier, etc.). The peak intensity of the zeolite is determined by electron diffraction (peak + background) in a preset angular zone (KαCu curve, 1 = 0.154 nm, usually 8 ° to 40 ° −2θ). This peak / (peak + background) ratio, which is the ratio of the area of the zeolite lines (peaks) to the total area of ()), is proportional to the amount of crystalline zeolite in the material. To calculate the crystalline portion of the Y zeolite sample, the peak intensity of the sample is compared to that of a sample considered to be 100% crystalline (eg, NaY). The peak intensity of perfectly crystalline NaY zeolite is about 0.55 to 0.60.
[0056]
The peak intensity of conventional USY zeolite is 0.45-0.55, and its crystalline fraction for fully crystalline NaY is 80% -95%. The peak intensity of the solid used in the present invention is less than 0.4, preferably less than 0.35. Thus, its crystalline portion is less than 70%, preferably less than 60%.
[0057]
Partially amorphous zeolites are prepared from commercially available Y zeolites, which generally have a high degree of crystallinity (at least 80%), using commonly used dealumination techniques. More generally, it is possible to start with zeolites having at least 60%, or at least 70%, of the crystalline part.
[0058]
Y zeolites commonly used in hydrocracking catalysts are made by modifying commercial Na-Y zeolites. This modification can produce a zeolite that is said to be stabilized, ultra-stabilized, or dealuminated. This modification is accomplished by at least one of the dealumination techniques, for example, hydrothermal treatment, or acid decomposition. Desirably, this modification is accomplished by combining three operations known in the art: hydrothermal treatment, ion exchange and acid decomposition.
[0059]
Further particularly preferred zeolites are highly acidic zeolites which are not totally dealuminated.
[0060]
The term "totally not dealuminated" is described in Atlas of the Zeolite Structure Type, W.W. M. Meier, D .; H. Olson and Ch. Means Y zeolite (structural type, FAU (faujasite)) according to the nomenclature developed in Baerlocher, 4th revised edition, 1996, Elsevier. The lattice constant of this zeolite may be reduced by extracting aluminum from the structure or framework during preparation. However, since aluminum is not chemically extracted, all SiO ₂ / Al ₂ 0 ₃ The ratio does not change. Such a totally non-dealuminized zeolite therefore has a silicon and aluminum composition (total SiO 2) equivalent to the starting non-dealuminized Y zeolite. ₂ / Al ₂ 0 ₃ Ratio). Values of other parameters (SiO ₂ / Al ₂ 0 ₃ (Ratio and lattice constant) are given below. This totally non-dealuminized Y zeolite can be in the hydrogen form, or the hydrogen is at least partially combined with a metal cation, such as an alkaline earth metal and / or atomic numbers 57-71. Is exchanged using a rare earth metal cation. Desirably, zeolites low in rare earth and alkaline earth elements are also used for catalysis.
[0061]
Y zeolites that are not entirely dealuminated generally have a lattice constant of 2.438 nm or greater, and a total SiO 2 of less than 8. ₂ / Al ₂ 0 ₃ Ratio, less than 21 and total SiO ₂ / Al ₂ 0 ₃ Frame SiO exceeding ratio ₂ / Al ₂ 0 ₃ With a ratio. Zeolites that are not entirely dealuminated are treated without extracting aluminum from the sample (eg, steam treatment, SiCl ₄ And the like).
[0062]
Further types of catalysts that are advantageous for hydrocracking include acidic amorphous oxide matrices of the alumina type doped with phosphorus, generally non-dealuminized, highly acidic Y zeolites and, optionally, It contains at least one element from group VIIA, especially fluorine.
[0063]
The invention is not limited to the preferred Y zeolites cited above, but other types of Y zeolites can be used in the present method.
[0064]
Prior to injection of the feedstocks, the catalysts are subjected to a sulfidation treatment to convert at least some of the metal species to sulfides before contacting the feedstock to be processed. This sulfidation activation treatment is well known to those skilled in the art and can be used in-situ, ie, in a reactor, or ex-situ, using any method described in the literature. It can be carried out.
[0065]
Conventional sulphidation processes, well known to those skilled in the art, can be carried out in the presence of hydrogen sulphide (pure or, for example, in a hydrogen / hydrogen sulphide mixture stream) at a temperature in the range from 150 ° C to 800 ° C, preferably It consists of heating at 250 ° C. to 600 ° C., generally in a through-bed (cross-bed) reaction zone.
[0066]
When the hydrotreating catalyst and hydrocracking catalyst are in the same reactor, or in two reactors without an intermediate separation wall, they are sulfurized simultaneously.
[0067]
Product separation
The liquid effluent from the hydrocracking is then separated into a naphtha cut, a diesel cut, possibly a kerosene cut (which may sometimes contain at least some of the diesel cut), and light LPG gas. Is distilled. Generally, after the purge, there remains a liquid residue which is advantageously recycled to the process.
[0068]
Obviously, hydrogen is also separated from the liquid effluent, which is then stripped before being distilled.
[0069]
Unexpectedly, for the process according to the invention, it is necessary to produce very high quality diesel that meets the specifications and further processing to improve its quality (severe hydrodesulfurization, hydrogenation ...). It turned out not.
[0070]
The process has a distillation point of 95% by volume below 360 ° C. (this distillation point is at most 350 ° C., or even at most 340 ° C.), a sulfur content of at most 50 ppm, generally at most 10 ppm, at least A cetane number of 52, more usually at least a cetane number of 54, preferably at most 6%, more usually at most 1% aromatic ring compound content, preferably a pour point below -10 ° C, preferably Can directly produce diesel with an aromatics content of less than 15% by weight.
[0071]
This method also produces fine kerosene with a smoke point greater than 20 mm, desirably greater than 22 mm, and a sulfur content less than 50 ppm, desirably less than 10 ppm. At least a portion of the kerosene can optionally be sent to a diesel pool, depending on the needs of the operator.
[0072]
Such diesel qualities have been upgraded in the future while allowing for the upgrading of "light" refinery feedstocks, such as existing gas oils, which must be subjected to excessive or subsequent severe processing due to strengthening specifications. It is worth noting that it can be obtained without treatment and for a much lower investment than high pressure hydrocracking.
[0073]
As regards the yield of the middle distillates formed (kerosene + diesel), they are at least 60% by volume, usually at least 65% by volume. Other products made are light LPG gas (at most 10% by weight, more usually at most 5% by weight) and naphtha (typically at least 20% by weight).
[0074]
Drawing
The method will be described briefly with reference to the figures.
[0075]
FIG. 1 is a flow sheet illustrating an embodiment of a medium pressure hydrocracking process. FIG. 2 is a flow sheet showing the prior art. 2B, 2C, 3 and 4 are flow sheets showing the method of the present invention incorporated into the catalytic cracking method.
[0076]
The medium pressure hydrocracking process is shown in FIG. The raw material to be processed enters through line 1. In the figure, it is added to the hydrocrack resid recycle through line 2 and hydrogen is added through line 3. It mixes with the recycled hydrogen supplied through line 5 and passes through heat exchanger 4. It is then passed through a reheater 6 to a medium pressure hydrocracking reactor (or reaction zone) 7 (optionally including an upstream hydrotreating zone (s)).
[0077]
Reactor 7 includes at least one catalyst bed 8 of at least one hydrocracking catalyst. Desirably, it may include at least one hydroprocessing catalyst upstream of the first bed 8. The liquid effluent leaving the reactor via line 9 then passes through a gas-liquid separator 10 for separating hydrogen, which is recycled to the hydrocracking reactor 7 via line 5.
[0078]
The separated liquid effluent exiting via line 11 is desirably sent through line 13 to a stripper 12 for separating naphtha and light gas, and the product effluent exiting via line 14 is at atmospheric pressure. Distillation is performed in the distillation column 15. This arrangement schematically shows a mode of distillation. Other known arrangements that result in separating the same product are also suitable.
[0079]
This produces a diesel that is withdrawn through line 16 and a resid that is separated from the purge through line 17 and recycled through line 2 to the hydrocracking reactor. Optionally, kerosene is obtained.
[0080]
The product separation zone separates the hydrocracked resid having a boiling point of at least 535 ° C. and recycles the purged resid line and optionally the purged resid to a hydrocracking zone or reactor. Including the line to be.
[0081]
This figure does not show the compressors and equipment used, which are well known to those skilled in the art.
[0082]
The hydrocracking process described here can advantageously be incorporated into a refinery in a catalytic cracking process (generally FCC: fluidized bed catalytic cracking).
[0083]
This results in a combined process that produces both high quality diesel and naphtha (for gasoline production).
[0084]
The invention also relates to an apparatus for performing the above-described method. This device
-T in the range of 250 ° C to 400 ° C ₅ Temperature and T at most 470 ° C ₉₅ A column for distilling a hydrocarbon feed to separate at least one fraction having a temperature;
At least one zone for hydrotreating the feed or the fraction,
At least one zone for medium-pressure hydrocracking of said fraction, said medium pressure being at least 70 bar, at most 100 bar;
At least one zone for separating the product in order to obtain a diesel with a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and a cetane number of more than 51;
including.
[0085]
In a particular implementation of the invention, shown below, the device comprises:
A column for atmospheric distillation of said crude material to separate at least naphtha, diesel and atmospheric residue;
A vacuum distillation column for treating the atmospheric residue and separating at least one vacuum distillate and vacuum residue;
-In the apparatus, the atmospheric distillation column or the vacuum distillation column has a T of 250 ° C. to 400 ° C. ₅ Temperature and T at most 470 ° C ₉₅ Including at least one line for collecting a fraction having a temperature.
At least one zone for hydrotreating said fraction, followed by at least one medium-pressure hydrocracking zone, and a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and 51 or more A device also comprising at least one zone for separating the product to obtain a diesel having a cetane number of
including.
[0086]
For a better understanding of the invention and its advantages, FIG. 2A shows the prior art and FIG. 2B shows the invention. Then, the method of the present invention will be described with reference to the drawings.
[0087]
FIG. 2A shows an existing device. The crude hydrocarbon feed (ie, crude oil) arriving through line 20 is distilled in atmospheric pressure column 21. One naphtha cut (line 22) (where the term "one" means "at least one"), one fuel cut (line 23) and one diesel cut (line 24). Separated.
[0088]
The atmospheric resid exiting through line 25 is vacuum distilled in vacuum distillation column 26. The vacuum distillate (line 27) is separated, leaving a vacuum resid (line 38).
[0089]
The vacuum distillate is sent to a catalytic cracking unit 28 (generally a fluidized bed), which comprises, inter alia, naphtha withdrawn through line 29, a highly aromatic diesel type fraction withdrawn through line 30 ( (Light cycle oil LCO) and a slurry or resid that is withdrawn through line 31.
[0090]
Typically, the vacuum resid is processed in a visbreaking unit 39, which produces, inter alia, both low quality naphtha (line 40) and diesel (line 41). The visbreaking resid (line 42) can only be used as fuel, like a slurry. Some of the LCO can help to flush the fuel.
[0091]
FIG. 2B shows the method and apparatus of the present invention combining medium pressure hydrocracking and catalytic cracking.
[0092]
The reference numbers in FIG. 2A are used, and the visbreakers are usually present in the device, but are not shown to simplify the figure.
[0093]
In addition to the elements of the prior art (FIG. 2A), the apparatus of the present invention (FIG. 2B) includes a medium pressure hydrocracker 32 which receives the light fraction from the vacuum distillation step fed through line 33.
[0094]
Apparatus 32 comprises a medium pressure or zone (s) hydrocracking reactor (s) and, inter alia, high quality diesel via line 34, naphtha and line 36 via line 35. Associated separation means for separating the hydrocracked resid purges that have passed through. Typically, device 32 also includes a hydrotreating zone prior to hydrocracking.
[0095]
At least a portion of the hydrocracking resid may be sent for catalytic cracking (device 28), but this is not required. The purge from the hydrocracker is advantageously sent to unit 28.
[0096]
This figure does not show the recycling of the purged resid to a hydrocracking reactor that also includes a hydrocracking or hydrotreating zone. Recycling and transport of the purge to the FCC can be performed separately or together.
[0097]
Within the context of the process of the invention, the cut point for the distilled diesel fraction (line 24) during atmospheric distillation is selected by the operator, for example as shown in FIG. 2B with FCC. Is done.
[0098]
Atmospheric resid (and thus comprising at least a portion of heavy atmospheric gas oil) is vacuum distilled into at least one light distillate (distillate) and at least one heavy distillate (distillate), Vacuum residue remains.
[0099]
The light fraction treated by hydrocracking has a T in the range of 250 ° C to 400 ° C. ₅ Temperature and T at most 470 ° C ₉₅ With temperature. It is light vacuum gas oil (LVGO). The end point is chosen by the operator according to the available columns and according to the desired quality improvement of the product. The light fraction is processed by the process of the present invention and has the other properties of the hydrocarbon feed described above.
[0100]
Generally, this light vacuum distillate treatment by medium pressure hydrocracking involves diesel distillation regardless of the type of reactor reserved for heavy distillate (s) and resid from vacuum distillation. Can be performed if the production and / or quality of the product is to be improved.
[0101]
In a further practice, instead of separating the atmospheric resid into light and heavy fractions by vacuum distillation and sending the light fraction (s) to the hydrocracking step, substantially the same as for atmospheric distillation T ₅ Temperature and T ₉₅ A heavy gas oil cut with temperature is taken (if the column type allows it). This mode is shown in FIG. 2C, which is indicated by the same reference numbers as for the previous figure, wherein the feed for unit 32 is atmospheric gas oil supplied via line 37. In this figure, line 33 is no longer present. In this case, the atmospheric resid boiling above the heavy gas oil is vacuum distilled, which also produces a resid and at least one vacuum distillate (herein referred to as heavy distillate). I do.
[0102]
Vacuum distillation bottoms (line 38) (which is generally at least 535 ° C, desirably at least 550 ° C or at least 565 ° C or even 570 ° C ₅ Having a temperature) can be subjected to, for example, visbreaking (shown in FIG. 1) or resid hydroconversion or coking.
[0103]
In all cases, at most 470 ° C T ₉₅ At least one heavy vacuum distillation fraction located between the light fraction with the temperature and the vacuum resid is subjected to catalytic cracking.
[0104]
FIG. 3 shows one apparatus and one method, in which the heavy fraction from the vacuum distillation subject to catalytic cracking is subjected to a hydrotreatment in zone 43 prior to said cracking. The reference numbers of the previous figure are again shown here.
[0105]
This hydrotreating prior to FCC is performed in the presence of at least one amorphous catalyst. All conventional hydrotreating catalysts can be used. Catalysts that may be mentioned include at least one non-noble metal Group VIII element (e.g., Co, Ni) and at least one Group VIB element (e.g., on an alumina or silica-alumina based support). Mo, W). The particularity of this process is that the operating conditions are: 25-90 bar, preferably less than 85 bar, or more preferably less than 80 bar, or more preferably less than 70 bar hydrogen gas partial pressure, and 350-450. C., preferably at least 10%, preferably at most 370-430.degree. C., adjusted to maintain a conversion of less than 40% of the product boiling below 350.degree. C., preferably 15-30%.
[0106]
This produces naphtha (line 44) and diesel (line 45), but of medium quality and is intended for use as domestic fuel or sent to a diesel pool.
[0107]
Next, the hydrotreated effluent is transferred to the catalytic cracking unit 28.
[0108]
FIG. 4 is a flow chart for the addition of the heavy diesel fraction to the device 32 where medium pressure hydrocracking is performed. In this run, in addition to the naphtha fraction (line 22), the kerosene fraction (line 23), the light LGO diesel fraction (line 46) and the heavy diesel fraction HGO (line 47), atmospheric distillates are obtained. can get. This heavy diesel fraction is sent to unit 32, where it is subjected to hydrocracking followed by medium pressure hydroprocessing.
[0109]
The present application describes a method for producing diesel and naphtha, wherein diesel production is performed by a medium pressure hydrocracking process as described above, and naphtha production is obtained essentially by catalytic cracking. Desirably, the hydrocracked purge is sent to a catalytic cracking step.
[0110]
Although we have described a preferred embodiment of this type of method, other embodiments and procedures that produce the same result are possible.
[0111]
To exemplify the advantages of the present invention, we will consider the production from existing refining schemes and from existing schemes for producing diesels that meet the 2005 standard, and from the schemes of the present invention. It is described below. In the scheme of FIG. 2A (existing standard 2000 scheme) processing 10 Mt / year of North Sea crude oil, we have:
・ Naphtha 3.17Mt / year
・ Jet fuel 0.73Mt / year
・ Diesel 2.32Mt / year
・ Home fuel 1.5Mt / year
Fuel from 565 ° C. + resid undergoing visbreaking: 40 cst fuel at 1.42 Mt / year (diluted with LCO, including slurry),
(Scheme 1).
[0112]
This diesel has a cetane number of 49 and a sulfur content of 2100 ppm. To meet the standard, it must be subjected to conventional desulfurization methods.
[0113]
Without changing the refinery scheme, but with diesel quality in compliance with the 2005 standard (95% point taken at 340 ° C.), we
・ Naphtha 3.32Mt / year,
・ Jet fuel cut 0.82Mt / year,
・ Diesel 2.13Mt / year,
・ Home fuel 1.36Mt / year,
565 ° C + 40 cst fuel from residual oil 1.43Mt / year,
(Scheme 2).
[0114]
This diesel has a cetane number of only 48 and must therefore be subjected to extremely severe hydrodesulfurization and hydrogenation that cannot be achieved with existing equipment.
[0115]
Naphtha pool is estimated to have a sulfur content of 270 ppm by weight, and subsequent severe treatment is required to reduce it to 10-50 ppm by weight. To avoid expensive investments, the naphtha fraction from the FCC is treated separately by severe hydrodesulfurization, with the disadvantage of reducing the octane number. Other naphtha fractions (eg, from visbreakers, crude oil distillation, etc.) are sent to a reforming step and possibly to an isomerizer prior to hydrotreating.
[0116]
Adding the hydrotreating step prior to catalytic cracking to Scheme 2 above (as shown in FIG. 3, but under hydrocracking) produces the following (Scheme 3):
・ Naphtha 3.06Mt / year,
・ Jet fuel 0.84Mt / year,
・ Diesel 2.57Mt / year,
・ Home fuel 1.40Mt / year,
・ 565c + 40cst fuel from residual oil 1.36Mt / year
The cetane number of diesel remains at about 48. FCC naphtha has a sulfur content of 15 ppm, and in naphthenic pools the sulfur content can be reduced to values as low as about 5.5 ppm without a substantial decrease in octane number.
[0117]
In a preferred scheme 4 of the invention involving medium pressure hydrocracking (FIG. 3), we
・ Naphtha 2.90Mt / year,
・ Jet fuel 0.86Mt / year,
・ Diesel 2.82Mt / year,
・ Home fuel 1.44Mt / year,
・ 40 cst fuel 1.34 Mt / year,
(Scheme 4).
[0118]
In this case, vacuum distillation separates the light fraction 350-410 ° C, the heavy fraction 410-565 ° C and 565 ° C + resid.
[0119]
In the hydrocracking, the conversion is almost complete (≧ 98%), ₂ Consumption 1.85% by weight, pressure 90 bar ppH ₂ It is.
[0120]
The resulting diesel is as follows:
95% point 340 ° C
Flash point> 60 ℃
Cetane number 56
Sulfur content <10 ppm
Polyaromatic ring content <1% by weight.
[0121]
Comparison of these figures shows the excellent quality of the diesel obtained using the scheme of the present invention. This quality has never been produced before.
[0122]
For the same product quality, we have saved 50 bar of hydrogen pressure compared to conventional hydrocracking, but this considerably reduces costs.
[0123]
In terms of productivity, the amount of product is similar to that of Scheme 3, but in contrast, the comparison with Scheme 2 (existing refinery, but meeting the 2005 standards) shows that for the same amount of crude oil, Shows the following important increases:
Diesel + 32.4%
Kerosene 4.9%
We have also been able to adjust the diesel / naphtha balance towards higher quality diesel while reducing 40 cst fuel production (-6.3%) and thus adapting the refinery to market needs. Furthermore, since the FCC unit does not run at full capacity, the operator can very advantageously introduce supplementary feedstocks (eg atmospheric resid) that can be processed under FCC. This addition is desirably made to the feed entering the vacuum distillation column (dotted line in FIG. 3).
[Brief description of the drawings]
FIG. 1 is a flow sheet showing an embodiment of a medium pressure hydrocracking method.
FIG. 2 is a flow sheet showing a conventional technique.
FIG. 2B is a flow sheet showing the method of the present invention incorporated into a catalytic cracking method.
FIG. 2C is a flow sheet showing the method of the present invention incorporated into the catalytic cracking method.
FIG. 3 is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.
FIG. 6 is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.

Claims (26)

95% distillation point less than 360 ° C., to a method for producing a diesel having a cetane number in excess of the sulfur content and 51 of 50ppm at most, _{T 5} temperature and high range the method of 250 ° C. to 400 ° C. Treating a hydrocarbon feed having a T ₉₅ temperature of 470 ° C., and wherein the process produces an effluent having an organic nitrogen content of 10 ppm or less, followed by at least one Y zeolite and at least one Y zeolite. And a medium pressure hydrocracking with a hydrocracking catalyst consisting of a matrix of at least one hydrogen dehydrogenating function, said hydrocracking exceeding 70 bar and at a hydrogen gas partial pressure of at most 100 bar. , at a temperature of at least 320 ° C., at least 200N l / N times per liter of _{H 2} / feed volume ratio and 0.15～7H ^-1 Is performed between the speed, the method is performed at 80% conversion at least volume, and the liquid effluent obtained by hydrocracking is distilled to separate the diesel process. 2. The method according to claim 1, wherein the conversion is at least 95% by volume. Hydrocarbon feedstock has a _{T 95} temperature in the range of three hundred ninety to four hundred and thirty ° C., The method according to claim 1 or 2. Hydrocarbon feedstock has a _{T 5} temperature in the range of three hundred and twenty to three hundred seventy ° C., the method according to any one of claims 1 to 3. The hydrocarbon feedstock is selected from the group consisting of heavy atmospheric gas oil, light vacuum gas oil, light vacuum distillate, a mixture of said feedstock and a mixture of said feedstock and diesel fraction. A method according to any one of the preceding claims. The process according to any of the preceding claims, wherein the hydrotreating and hydrocracking are performed in the same reactor and without intermediate separation of the gas generated by the hydrotreating. The process according to any of the preceding claims, wherein the hydrocracking resid is recycled to the process after purging. Process according to any of the preceding claims, wherein the diesel obtained has a 95% point at the most at 340C, a sulfur content of at most 10 ppm and a cetane number of at least 54. The hydroprocessing catalyst, by weight,
5% to 40% of at least one element from group VIB and non-noble metal group VIII (% oxide),
0-20% of at least one promoter element (oxide%) selected from phosphorus, boron, silicon;
0-20% of at least one group VIIB element,
0% Group VIIA element,
0-60% of at least one VB group element,
0.1-95% of at least one matrix,
And the hydrocracking catalyst comprises:
0.1-80% by weight Y zeolite,
0.1 to 40% by weight of at least one element from Group VIB and Group VIII (% oxide);
0.1 to 99.8% by weight of matrix (% oxide),
0 to 20% by weight of at least one element selected from the group made by P, B, Si (% oxide)
0% by weight of at least one Group VIIA element; 0-20% by weight of at least one Group VIIB element; 0-60% by weight of at least one Group VB element. The method according to any one of claims 1 to 8. 250 ° C. to 400 ° C. of T ₅ temperature and at most the raw material having a T ₉₅ temperature of 470 ° C. is light fractions from vacuum distillation of atmospheric residue, according to any one of claims 1 to 9 Method. Vacuum distillation also produces a vacuum resid having a boiling point of at least 535 ° C. and at least one heavy fraction located between the light fraction and the resid, wherein at least a portion of the heavy fraction is 11. The method of claim 10, wherein the method is subjected to catalytic cracking. The hydrocarbon feedstock processed by medium pressure hydrocracking is heavy atmospheric gas oil from atmospheric distillation, and the atmospheric residual oil boiling above the gas oil is at least one heavy vacuum decompressed for catalytic cracking. The process according to any of the preceding claims, wherein the distillation is carried out under reduced pressure to produce a distillate fraction and a vacuum resid. The process according to any of the preceding claims, wherein the medium pressure hydrocracking purge is subjected to catalytic cracking. Before being subjected to catalytic cracking, the heavy vacuum distillate is converted at a temperature of 350 to 430 ° C. under a hydrogen gas partial pressure of 25 to 90 bar at a conversion of at least 10% and less than 40% by volume, 14. The process according to any of the preceding claims, wherein the process is hydrotreated to a product boiling below 350 <0> C. 15. The method of any of the preceding claims, wherein the vacuum resid is subjected to a treatment by a method selected from the group consisting of visbreaking, resid hydroconversion and coking methods. The following steps,
Atmospheric distillation of the crude hydrocarbonation feedstock to produce at least one naphtha fraction, at least one kerosene (kerosene) fraction, at least one diesel fraction and an atmospheric residue.
Vacuum distillation of atmospheric resid to separate at least one light distillate fraction, at least one heavy distillate fraction and vacuum resid;
-Treatment of the light fraction by the process according to any one of claims 1 to 15, with the production of a hydrocracked resid;
Catalytic cracking of at least one heavy cut, optionally with the addition of at least a portion of the hydrocracking resid;
For the treatment of crude hydrocarbon feedstocks. The following steps,
Atmospheric distillation of the crude hydrocarbonation feedstock to produce at least one naphtha cut, at least one kerosene cut, at least one diesel cut, heavy atmospheric gas oil and atmospheric resid;
-Vacuum distillation of atmospheric resid to separate at least one heavy distillate fraction and vacuum resid,
Treatment of the heavy oil fraction by a process according to any one of claims 1 to 15, with the production of a hydrocracked resid;
A process for the treatment of a crude hydrocarbonization feedstock comprising catalytic cracking of at least one heavy cut, optionally with the addition of at least a portion of the hydrocracking residue. 17. Atmospheric distillation also produces a heavy atmospheric gas oil cut (fraction), said cut also being treated with said light fraction by the method according to any one of claims 1 to 15. The method described in. 19. The method according to any one of claims 16 to 18, which also comprises treating the vacuum residue by visco-reduction. · 250 ° C. to 400 ° C. range T ₅ temperature and at most the tower for distilling the hydrocarbon feed to separate at least one fraction having a T ₉₅ temperature of 470 ° C.,
At least one zone for hydrotreating the feed or the fraction,
Medium pressure of said fraction, at least one zone for hydrocracking, wherein said pressure is above 70 bar and at most 100 bar;
A 95% distillation point below 360 ° C. at least one zone for separating the product in order to obtain a diesel having a sulfur content of at most 50 ppm and a cetane number of more than 51;
For producing diesel consisting of A column for atmospheric distillation of the crude material, at least for separating naphtha, diesel and atmospheric residue;
A vacuum distillation column for treating the atmospheric residue and separating at least one vacuum distillate and vacuum residue;
- In that device, atmospheric distillation column or vacuum distillation column comprises at least one line recovering a fraction with a T ₉₅ temperature of 470 ° C. Both T ₅ temperature and high in the range of 250 ° C. to 400 ° C.,
At least one zone for hydrotreating said fraction, followed by at least one medium-pressure hydrocracking zone, a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and cetane above 51 An apparatus also comprising at least one zone for separating the product in order to obtain a diesel having a
21. An apparatus for producing diesel from a crude hydrocarbon feed according to claim 20. 22. Apparatus according to claim 20 or claim 21 comprising a hydrotreating zone located before the hydrocracking zone and in the same reactor. A product separation zone separates the hydrocracked resid having a boiling point of at least 535 ° C. and recycles the resid to a purge line and optionally the hydrocracking zone or reactor. 23. Apparatus according to any one of claims 20 to 22, comprising a line for: At most comprising at least one catalytic cracking zone for treating the vacuum distillation fraction located between the fraction with vacuum residue having a T ₉₅ temperature of 470 ° C., in any one of claims 20 to 23 The described device. 25. The apparatus according to any one of claims 20 to 24, comprising a line for supplying a purge to the catalytic cracking zone. 26. Apparatus according to any one of claims 20 to 25, comprising a hydrotreating zone before the catalytic cracking zone.

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