Improved residuum conversion process including a deep hydroconversion step and a deasphalting step
阅读说明：本技术 包括深度加氢转化步骤和脱沥青步骤的改善的渣油转化方法 (Improved residuum conversion process including a deep hydroconversion step and a deasphalting step ) 是由 J·马克斯 M·德雷亚尔 F·弗涅 J-F·勒科 于 2018-12-07 设计创作，主要内容包括：本发明涉及转化其中至少50重量％在至少300℃的温度下沸腾的重质烃原料、特别是减压渣油的方法。对所述原料进行第一深度加氢转化步骤a),任选地随后进行分离轻质馏分的步骤b),并且由步骤b)获得其中至少80重量％具有至少250℃的沸腾温度的重质渣油馏分。然后对来自步骤b)的所述馏分或来自步骤a)的流出物进行第二深度加氢转化步骤c)。步骤a)至步骤c)的总时空速小于0.1h<Sup>-1</Sup>。将来自步骤c)的流出物分馏以分离出轻质馏分。将获得的其中80重量％在至少300℃的温度下沸腾的重质馏分送至脱沥青步骤e)。然后优选在选自沸腾床加氢转化、流化床催化裂化和固定床加氢裂化的步骤f)中转化脱沥青馏分DAO。(The present invention relates to a process for converting heavy hydrocarbon feedstocks, in particular vacuum residuum, of which at least 50 wt.% boils at a temperature of at least 300 ℃. Said feedstock is subjected to a first deep hydroconversion step a), optionally followed by a step b) of separating a light fraction, and a heavy residue fraction at least 80% by weight of which has a boiling temperature of at least 250 ℃ is obtained from step b). Said fraction from step b) or the effluent from step a) is then subjected to a second deep hydroconversion step c). The total hourly space velocity of the steps a) to c) is less than 0.1h ‑1 . Fractionating the effluent from step c) to separate a light fraction. 80% by weight of the obtained mixture isThe heavy fraction boiling at a temperature of at least 300 ℃ is sent to the deasphalting step e). The deasphalted fraction DAO is then preferably converted in a step f) selected from ebullated bed hydroconversion, fluid catalytic cracking and fixed bed hydrocracking.)
1. Process for converting a hydrocarbon feedstock, at least 50 wt.%, preferably at least 80 wt.% of which boils at a temperature of at least 300 ℃, comprising the following successive steps:
-in step a), in the presence of hydrogen, at an absolute pressure of between 2MPa and 35MPa, at a temperature of between 300 ℃ and 550 ℃, using 50Sm3/m3-5000Sm3/m3With a catalyst comprising at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten,
-an optional step b) in which a light fraction is separated from part or all of the effluent resulting from said first hydroconversion and at least one heavy fraction is obtained in which at least 80% by weight has a boiling point of at least 250 ℃,
-in step c), in the presence of hydrogen, at an absolute pressure of between 2MPa and 35MPa, at a temperature of between 300 ℃ and 550 ℃, using 50Sm3/m3-5000Sm3/m3A second deep hydroconversion of part or all of the liquid effluent resulting from step a) or of part or all of the heavy fraction resulting from step b) with a catalyst comprising at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten,
the total hourly space velocity of the steps a) to c) is less than 0.1h-1The total hourly space velocity is the flow rate of the liquid feedstock of hydroconversion step a) at standard temperature and standard pressure conditions divided by the total volume of the reactors of step a) and step c),
-a step d) in which a part or the whole of the effluent resulting from said second hydroconversion is separated into at least one light fraction and at least one heavy fraction at least 80% by weight of which has a boiling point of at least 300 ℃,
-a step e) in which said heavy fraction resulting from step d) is deasphalted at a temperature ranging from 60 ℃ to 250 ℃ with at least one hydrocarbon solvent having from 3 to 7 carbon atoms and a solvent/feedstock ratio (volume/volume) ranging from 4/1 to 9/1, and a deasphalted fraction DAO and bitumen are obtained.
2. The process according to claim 1, comprising a step f) of converting part or all of the deasphalted fraction DAO, optionally distilled.
3. The process according to claim 2, wherein the DAO is distilled before the conversion step f), so as to separate a heavy fraction of which at least 80% by weight has a boiling point of at least 375 ℃, or at least 400 ℃, or at least 450 ℃, or at least 500 ℃, preferably at least 540 ℃, and to send part or all of said heavy fraction to the conversion step f).
4. The process according to any one of the preceding claims, wherein part or all of the DAO fraction is preferably sent directly to a conversion step operating with a process selected from fixed bed hydrocracking, fluid catalytic cracking and ebullated bed hydroconversion, which may include a prior hydrotreatment.
5. Process according to claim 4, wherein in the presence of hydrogen, at an absolute pressure of between 5MPa and 35MPa, advantageously at a temperature of between 300 ℃ and 500 ℃, for 0.1h-1To 5h-1Under HSV of (1) at 100Sm3/m3-1000Sm3/m3A fixed bed hydrocracking of a portion or all of said deasphalted fraction DAO is carried out under hydrogen content of liquid feedstock and in the presence of a catalyst containing at least one non-noble metal element from group VIII and at least one element from group VIb and comprising a support containing at least one zeolite.
6. The process according to claim 4, wherein a part or all of the deasphalted fraction DAO is subjected to fluid catalytic cracking FCC in the presence of a catalyst, preferably free of metals but comprising alumina, silica/alumina, preferably comprising at least one zeolite.
7. The process of claim 4 wherein the catalyst is used in the presence of hydrogen at an absolute pressure of from 2MPa to 35MPa, at a temperature of from 300 ℃ to 550 ℃, at 50Sm3/m3-5000Sm3/m3Hydrogen amount of liquid raw material at 0.1h-1To 10h-1And subjecting a portion or all of the deasphalted fraction DAO to ebullated-bed hydroconversion in the presence of a catalyst comprising a support and at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten.
8. Process according to one of the preceding claims, wherein at least a portion of the deasphalted fraction DAO is recycled to step a) and/or step c).
9. The process according to any one of the preceding claims, wherein in separation step d) the effluent resulting from the second hydroconversion is separated into at least one light fraction and at least one heavy fraction at least 80 wt% of which has a boiling point of at least 375 ℃, or at least 400 ℃, or at least 450 ℃, or at least 500 ℃, preferably at least 540 ℃.
10. The method of one of the preceding claims, wherein:
-using 100Sm at an absolute pressure comprised between 5MPa and 25MPa and preferably between 6MPa and 20MPa, at a temperature comprised between 350 ℃ and 500 ℃ and preferably comprised between 370 ℃ and 430 ℃, more preferably comprised between 380 ℃ and 430 ℃3/m3-2000Sm3/m3Very preferably 200Sm3/m3-1000Sm3/m3And hydrogen amount of at least 0.05h-1Preferably 0.05h-1To 0.09h-1The Hourly Space Velocity (HSV) of step a) and step c),
-carrying out step e) with a solvent selected from butanes, pentanes and hexanes and mixtures thereof.
Technical Field
The present invention relates to the conversion of a heavy hydrocarbon feedstock comprising at least 50 wt% of a fraction having a boiling point of at least 300 ℃. They are crude oils or feedstocks which result directly or after treatment from the atmospheric and/or vacuum distillation of crude oils, for example atmospheric or vacuum residues.
Increasing the value of these residues is quite difficult both from a technical and an economic point of view. This is because new regulatory restrictions greatly reduce the maximum allowable sulfur content in bunker fuel oil (from 3 wt% to 0.5 wt%). In addition, there is a particular need in the market for fuels that can be distilled at atmospheric pressure, at temperatures below 380 ℃ and even below 320 ℃.
Prior Art
Patent FR 2906814 by the applicant company describes a process comprising a deasphalting step to produce a deasphalted oil, a hydroconversion step of the deasphalted oil to produce an effluent and a distillation step of the effluent to produce a residual oil which is returned to the deasphalting step together with the feedstock, connected in succession. The patent describes that the reaction time is 0.1h-1To 5h-1The hydroconversion step is carried out at a conventional space velocity (HSV) and the sequence of processes for the SDA step is carried out upstream of the hydroconversion step. The large amounts of bitumen produced limit the maximum overall conversion level of the process.
Patent FR 2964386 of the applicant company describes a sequence of processes for treating a feedstock produced from crude oil or from the atmospheric or vacuum distillation of crude oil. The process comprises an ebullated bed hydroconversion step (known as H-Oil or LC-coming process) followed by a step of separating the light fraction (boiling less than 300 ℃ C., preferably less than 375 ℃ C.) and the resulting heavy fraction is directly subjected to a deasphalting step to produce deasphalted Oil (DAO). The DAO may be hydrocracked or hydrotreated or fractionated.
The fluidized bed hydroconversion step is carried out for 0.1h-1To 10h-1At a space velocity of (HSV). Examples of this patent are at HSV = 0.3h-1And about 60 wt.% conversion with respect to the ebullated bed portion (relative to 540 c + resid, i.e., resid boiling at 540 c or higher).
This simple and economical process allows thermal integration in the same reaction section and allows to obtain DAO with high quality; however, the yield of bitumen is high, which limits the maximum overall conversion achievable by the process.
It is also known (patent US 7938952) to use for at least 0.1h-1Is operated with two ebullated bed hydroconversion steps (known as the H-Oil process) with intermediate separation set to separate the light fraction and the resulting heavy fraction to the second hydroconversion step, followed by direct distillation of the effluent from the second hydroconversion. "Total space velocity" is understood to mean the flow rate of the hydrocarbon feedstock at standard temperature and standard pressure conditions divided by the total volume of the reactor constituting the hydroconversion step.
Patent FR 3033797 of the applicant company describes a process for treating a feedstock produced from crude oil or from the atmospheric or vacuum distillation of crude oil, at least 80% by weight of which has a boiling point of at least 300 ℃. The process comprises a hydroconversion step (first hydroconversion) followed by separation of the light fraction (boiling point less than 350 ℃) and hydroconversion of the heavy fraction obtained (second hydroconversion) independently of the first hydroconversion; the obtained effluent is subsequently fractionated by distillation. The hydroconversion process is at a low total HSV,Preferably 0.05h-1To 0.09h-1The process is carried out as follows.
The low total HSV brings the advantage of a high degree of purification, which makes it possible to obtain a residue with a low content of asphaltenes and conradson carbon residues, for a high conversion level (> 75%) of the residue. The stability of the liquid effluent is improved. The deposit content at the hydroconversion outlet is reduced, thus allowing better operability of the process. The overall conversion of the process is limited by the unconverted heavy effluent.
Summary of The Invention
Processes with improved performance qualities, in particular with high conversion of fuels (naphtha, kerosene, gas oil), are now being sought to adapt to the market.
The process of the latest prior art (FR 3033797) can be modified to increase the conversion of the deep hydroconversion step, while further reducing the total HSV.
The applicant company has demonstrated that a better solution is to add a deasphalting step to the process of the latest prior art, which makes it possible to obtain high levels of yield and quality of DAO, and to treat DAO in at least one conversion step, the latter preferably being carried out at high HSV, thus increasing the conversion, contributing at the same time to a significant increase in operability, saving a large amount of investment funds, and obtaining a better return on investment. The present invention may also further reduce the amount of pitch produced as compared to processes having a larger total HSV.
More specifically, the present invention relates to a process for converting a hydrocarbon feedstock, at least 50 wt.%, preferably at least 80 wt.%, of which boils at a temperature of at least 300 ℃, comprising the following successive steps:
-in step a), in the presence of hydrogen, at an absolute pressure of between 2MPa and 35MPa, at a temperature of between 300 ℃ and 550 ℃, using 50Sm3/m3-5000Sm3/m3With a catalyst comprising at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten,
-an optional step b) in which a light fraction is separated from part or all of the effluent resulting from said first hydroconversion and at least one heavy fraction is obtained in which at least 80% by weight has a boiling point of at least 250 ℃,
-in step c), in the presence of hydrogen, at an absolute pressure of between 2MPa and 35MPa, at a temperature of between 300 ℃ and 550 ℃, using 50Sm3/m3-5000Sm3/m3A second deep hydroconversion of part or all of the liquid effluent resulting from step a) or of part or all of the heavy fraction resulting from step b) with a catalyst comprising at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten,
and the total hourly space velocity of steps a) to c) is less than 0.1h-1The total hourly space velocity is the flow rate of the liquid feedstock of hydroconversion step a) at standard temperature and standard pressure conditions divided by the total volume of the reactors of step a) and step c),
-a step d) in which a part or the whole of the effluent resulting from said second hydroconversion is separated into at least one light fraction and at least one heavy fraction at least 80% by weight of which has a boiling point of at least 300 ℃,
-a step e) in which said heavy fraction resulting from step d) is deasphalted at a temperature ranging from 60 ℃ to 250 ℃ with at least one hydrocarbon solvent having from 3 to 7 carbon atoms and a solvent/feedstock ratio (volume/volume) ranging from 4/1 to 9/1, and a deasphalted fraction DAO and bitumen are obtained.
Advantageously, the process comprises a step f) of converting part or all of the optionally distilled deasphalted fraction DAO.
Preferably, the DAO is distilled before the conversion step f), so as to separate a heavy fraction of which at least 80% by weight has a boiling point of at least 375 ℃, or at least 400 ℃, or at least 450 ℃, or at least 500 ℃, preferably at least 540 ℃, and to send part or all of said heavy fraction to the conversion step f).
Preferably, part or all of the DAO fraction is preferably fed directly to a conversion step operating with a process selected from fixed bed hydrocracking, fluid catalytic cracking and ebullated bed hydroconversion, for which a prior hydrotreatment may be included.
According to a preferred embodiment, in the presence of hydrogen, at an absolute pressure of between 5MPa and 35MPa, advantageously at a temperature of between 300 ℃ and 500 ℃, for 0.1h-1To 5h-1HSV and 100Sm3/m3-1000Sm3/m3(Standard cubic meter (Sm)3) Per cubic meter (m)3) Liquid feedstock) and in the presence of a catalyst comprising at least one non-noble metal element from group VIII and at least one element from group VIb and comprising a support comprising at least one zeolite.
According to another preferred form, a part or all of the deasphalted fraction DAO is subjected to fluid catalytic cracking FCC in the presence of a catalyst, preferably free of metals but comprising alumina, silica/alumina and preferably comprising at least one zeolite.
According to another preferred form, in the presence of hydrogen, at an absolute pressure of between 2MPa and 35MPa, at a temperature of between 300 ℃ and 550 ℃, at 50Sm3/m3-5000Sm3/m3(Standard cubic meter (Sm)3) Per cubic meter (m)3) Liquid feed) at 0.1h-1To 10h-1And subjecting a portion or all of the deasphalted fraction DAO to ebullated-bed hydroconversion in the presence of a catalyst comprising a support and at least one group VIII metal selected from nickel and cobalt and at least one group VIb metal selected from molybdenum and tungsten.
At least a portion of the deasphalted fraction DAO can be recycled to step a) and/or step c).
Advantageously, in the separation step d), the effluent resulting from said second hydroconversion is separated into at least one light fraction and at least one heavy fraction at least 80% by weight of which has a boiling point of at least 375 ℃, or at least 400 ℃, or at least 450 ℃, or at least 500 ℃, preferably at least 540 ℃.
Typically, 100Sm is employed at an absolute pressure of from 5MPa to 25MPa and preferably from 6MPa to 20MPa, at a temperature of from 350 ℃ to 500 ℃ and preferably from 370 ℃ to 430 ℃, more preferably from 380 ℃ to 430 ℃3/m3-2000Sm3/m3Very preferably 200Sm3/m3-1000Sm3/m3And hydrogen amount of at least 0.05h-1Preferably 0.05h-1To 0.09h-1The Hourly Space Velocity (HSV) of (c) carrying out steps a) and c).
Typically, step e) is carried out with a solvent selected from butane, pentane and hexane and mixtures thereof.
Detailed Description
Raw materials (filler)
Feedstocks which are treated in the context of the present invention are those in which at least 50% by weight, preferably at least 80% by weight, have a boiling point of at least 300 ℃ (T20 ═ 300 ℃), preferably at least 350 ℃, or at least 375 ℃.
These are crude oils or heavy hydrocarbon fractions resulting from atmospheric and/or vacuum distillation of crude oils. These may also be atmospheric and/or vacuum residues, in particular those resulting from hydrotreatment, hydrocracking and/or hydroconversion. These may also be vacuum distillates, fractions produced from catalytic cracking units (e.g. FCC (fluid catalytic cracking)), from coking units or from visbreaking units.
Preferably, these are vacuum residues. Typically, these residues are fractions in which at least 80 wt.% boils at a boiling point of at least 450 ℃ or higher, and most often at least 500 ℃ or at least 540 ℃.
Aromatic fractions extracted from units producing lubricating oil, deasphalted oil (raffinate produced by the deasphalting unit), or asphalt (residue produced by the deasphalting unit) may also be suitable for use as feedstocks.
The feedstock may also be a residual fraction produced by direct liquefaction of Coal (e.g., atmospheric and/or vacuum residual oils produced by the H-Coal @ process), a vacuum distillate produced by direct liquefaction of Coal (e.g., by the H-Coal @) pyrolysis, a residual oil produced by pyrolysis of Coal or shale oil, or a residual fraction produced by direct liquefaction of lignocellulosic biomass, used alone or as a mixture with Coal and/or petroleum fractions.
All of these starting materials may be used individually or as mixtures.
The above-mentioned raw materials contain impurities such as metals, sulphur, nitrogen, Conradson carbon residue and heptane insolubles, also known as C7Asphaltenes. The metal content is typically greater than 20 ppm by weight, most typically greater than 100 ppm by weight. The sulfur content is greater than 0.1 wt%, typically greater than 1 wt%, or greater than 2 wt%. C7The content of asphaltenes (heptane-insoluble asphaltenes according to standard NFT 60-115) is at least 0.1% by weight and is generally greater than 3% by weight. The conradson carbon content is at least 3 wt.%, typically at least 5 wt.%. The conradson carbon content is defined by the standard ASTM D482, which represents a well known assessment of the residual amount of carbon produced after pyrolysis under standard temperature and pressure conditions for a person skilled in the art. These contents are all expressed in weight% relative to the total weight of the feedstock.
First deep hydroconversion step (step a)
The feedstock is treated in a hydroconversion step a) comprising at least one or more three-phase reactors arranged in series and/or parallel. These hydroconversion reactors may be, in particular, fixed bed, moving bed, ebullating bed and/or mixed bed type reactors, depending on the feedstock to be treated. In the present patent application, the term mixed bed refers to a mixed bed of catalysts having very different particle size distributions, which contains both at least one catalyst retained in the reactor (typical function of an ebullating bed) and at least one entrained catalyst (slurry state) entering the reactor with the feedstock and being entrained out of the reactor with the effluent (typical function of an entrained bed).
The invention is particularly suitable for ebullated bed reactors. Thus, this step is advantageously carried out using the techniques and conditions of the H-Oil @ process described, for example, in patents US 4521295, or US 4495060, or US 4457831, or in Aiche's paper "Second Generation structured bed technology" (3.19-23.1995, Houston, Texas, paper No. 46 d). Each reactor advantageously comprises a recirculation pump which can maintain the catalyst in an ebullating bed by continuously recirculating at least one liquid fraction which is advantageously withdrawn at the top of the reactor and reinjected at the bottom of the reactor.
In this step a), the feedstock is converted under specific hydroconversion conditions. Step a) is carried out at an absolute pressure of from 2MPa to 35MPa, preferably from 5MPa to 25MPa, preferably from 6MPa to 20MPa, at a temperature of from 300 ℃ to 550 ℃, preferably from 350 ℃ to 500 ℃, preferably from 370 ℃ to 430 ℃, more preferably from 380 ℃ to 430 ℃. The amount of hydrogen advantageously mixed with the feedstock is preferably 50Sm at standard temperature and standard pressure conditions3/m3-5000Sm3/m3Liquid feedstock, preferably 100Sm3/m3-2000Sm3/m3Very preferably 200Sm3/m3-1000Sm3/m3。
The hydroconversion catalyst used in step a) comprises one or more elements from
The catalyst comprises at least one non-noble group VIII metal selected from nickel and cobalt, preferably nickel, and at least one group VIb metal selected from molybdenum and tungsten, and preferably the group VIb metal is molybdenum.
Advantageously, the hydroconversion catalyst of step a) is a catalyst comprising an alumina support and at least one group VIII metal selected from nickel and cobalt, preferably nickel, and at least one group VIb metal selected from molybdenum and tungsten; preferably, the group VIb metal is molybdenum. Preferably, the hydroconversion catalyst comprises nickel and molybdenum.
In general, the content of non-noble metal from group VIII, in particular nickel, expressed in weight of metal oxide, in particular NiO, is advantageously between 0.5% and 10% by weight, preferably 1% by weight-6% by weight and in the form of metal oxides (in particular MoO)3) The content of metal from group VIb, in particular molybdenum, expressed by weight of (A) is advantageously between 1% and 30% by weight, preferably between 4% and 20% by weight.
The catalyst is advantageously used in the form of extrudates or beads.
The beads have a diameter of, for example, 0.4mm to 4.0 mm.
The extrudate has, for example, a cylindrical shape with a diameter of 0.5mm to 4.0mm and a length of 1mm to 5 mm. The extrudate may also be an object having a different shape (e.g., regular or irregular trilobes, quadralobes, or other polylobes). Catalysts having other forms may also be used.
The size of these catalysts having different forms can be characterized by the equivalent diameter. The equivalent diameter is defined by six times the ratio of the volume of the particle to the external surface area of the particle. Thus, the equivalent diameter of the catalyst used in extrudate, bead or other form is from 0.4mm to 4.4 mm.
These catalysts are well known to those skilled in the art. The metal content is expressed relative to the total weight of the catalyst.
In one embodiment according to the invention, the deep hydroconversion step a) is carried out in a mixed bed comprising both at least one catalyst held in the reactor and at least one entrained catalyst entering the reactor with the feedstock and being entrained out of the reactor with the effluent. In this case, entrained catalyst (also referred to as slurry catalyst) is used in addition to the catalyst maintained in the ebullated-bed reactor in the process according to the invention. Unlike the catalyst held in the reactor, the entrained catalyst has a particle size distribution and density suitable for its entrainment. Entrainment of the catalyst is understood to mean that it is circulated through a liquid stream in the three-phase reactor or reactors, the catalyst being circulated with the feed from the bottom upwards into the three-phase reactor or reactors and being withdrawn from the three-phase reactor or reactors together with the liquid effluent produced. Due to its small size, which can vary from a few nanometers to about one hundred microns (typically 0.001 μm to 100 μm), the entrained catalyst is well dispersed in the feedstock to be converted, greatly improving the hydrogenation and hydroconversion reactions throughout the reactor, reducing coke formation and increasing the conversion of the heavy fraction of the feedstock. These entrained catalysts are well known to those skilled in the art.
The entrained catalyst may be formed and activated ex situ outside of the reactor under conditions suitable for activation and then injected with the feedstock. Entrained catalyst may also be formed and activated in situ under the reaction conditions of one of the hydroconversion steps.
The entrained catalyst or precursor thereof is injected into the inlet of the reactor together with the feedstock to be converted. The catalyst flows through the reactor with the converted feedstock and products, which are then entrained out of the reactor with the reaction products. The entrained catalyst is present in the form of a powder (patent US 4303634), as is the case with the entrained supported catalysts described below, or in the form of a "soluble" catalyst (patent US 5288681). In the reactor, the entrained catalyst is in the form of dispersed solid particles, colloids, or molecular entities dissolved in the feedstock, depending on the nature of the catalyst. Such entrained catalysts and precursors that can be used in the process according to the invention are widely described in the literature.
The entrained catalyst used may be a powder of a heterogeneous solid (e.g. natural ore, iron sulphate, etc.), a dispersed catalyst produced from a water-soluble precursor (e.g. phosphomolybdic acid, ammonium molybdate or a mixture of Mo or Ni oxide and aqueous ammonia), or a dispersed catalyst produced from an organic phase-soluble precursor. Preferably, the entrained catalyst used is generated from an organic phase-soluble precursor. The organic phase-soluble precursor is preferably selected from organometallic compounds comprising molybdenum naphthenate, cobalt naphthenate, iron naphthenate and nickel naphthenate and also polycarbonyl compounds of these metals Mo, Co, Fe and Ni, for example molybdenum 2-ethylhexanoate or nickel 2-ethylhexanoate, molybdenum acetylacetonate or nickel acetylacetonate, C7-C12Mo or W salts of fatty acids, and the like. Preferably, the precursorIs molybdenum naphthenate. The entrained catalyst may be used in the presence of a surfactant for improving the dispersion of the metal, particularly when the catalyst is a bimetallic catalyst.
According to one embodiment, an "oil soluble" entrained catalyst is used and the precursor is mixed with a carbon feedstock (which may be part of the feedstock to be treated, an external feedstock, etc.), the mixture is optionally dried, at least partially dried, and then or simultaneously sulfided and heated by the addition of a sulfur-containing compound. The preparation of these entrained catalysts is described in the prior art.
The additives may be added during the preparation of the entrained catalyst or added to the entrained catalyst prior to its injection into the reactor. Such additives are, for example, gas oils, aromatic additives, solid particles preferably less than 1mm in size, and the like. Preferred additives are inorganic oxides, such as alumina, silica or mixed Al/Si oxides, used supported catalysts (e.g. supported on alumina and/or silica) comprising at least one element from group VIII (e.g. Ni or Co) and/or at least one element from group VIb (e.g. Mo or W). Mention will be made, for example, of the catalysts described in patent US 2008/177124. Optionally pretreated coke may also be used. These additives are widely described in the literature. The entrained catalyst may advantageously be obtained by injecting at least one active phase precursor directly into the hydroconversion reactor(s) and/or into the feedstock before introducing it into the hydroconversion step(s). The addition of the precursor may be introduced continuously or intermittently (depending on the operation, the type of feedstock being processed, the product specifications and operability sought). According to one or more embodiments, the one or more entrained catalyst precursors are premixed with a hydrocarbon oil consisting of, for example, hydrocarbons (wherein at least 50 wt.% relative to the total weight of the hydrocarbon oil has a boiling point in the range of from 180 ℃ to 540 ℃), thereby forming a dilute precursor premix. In accordance with one or more embodiments, the precursor or dilute precursor premix is dispersed in the heavy hydrocarbon feedstock, for example, by dynamic mixing (e.g., using a rotor, agitator, etc.) or by static mixing (e.g., using an injector, by forced feeding, via a static mixer, etc.), or simply adding the precursor or dilute precursor premix to the feedstock to obtain a mixture. Any mixing and stirring technique known to those skilled in the art may be used to disperse the precursor or dilute precursor mixture in the feedstock for the hydroconversion step or steps.
The active phase precursor or precursors of the unsupported catalyst can be in liquid form, for example metal precursors soluble in the organic medium, such as molybdenum octoate and/or molybdenum naphthenate, or water-soluble compounds, such as, in particular, ammonium phosphomolybdate and/or heptamolybdate.
The entrained catalyst may be formed and activated ex situ outside the reactor under conditions suitable for activation and then injected with the feedstock. The entrained catalyst may also be formed and activated in situ under the reaction conditions of one of the hydroconversion steps.
According to one embodiment, the entrained catalyst may be supported, that is to say it comprises a support for the active phase. In this case, the supported catalyst can be advantageously obtained by:
by grinding fresh or used supported hydroconversion catalysts, or by grinding a mixture of fresh and used catalysts, or
By impregnating at least one active phase precursor on a support having a size suitable for the entrained particle size distribution of the catalyst, preferably ranging from 0.001 μm to 100 μm.
The entrained supported catalyst preferably comprises a support such as silica, alumina, silica/alumina, titania, clay, carbon, coal, coke, carbon black, lignite or combinations of these structures, with alumina being highly preferred.
The active phase of the entrained supported catalyst comprises one or more elements from
In the present specification, the family of chemical elements is specified according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, D.R. Lide eds., 81 th edition, 2000-2001). For example, group VIII metals according to the CAS classification correspond to metals according to
In the case of entrained supported catalysts, the content of non-noble metals from group VIII, in particular nickel, expressed as weight of metal oxide, in particular NiO, is advantageously from 0.5% to 10% by weight, preferably from 1% to 6% by weight. With metal oxides, in particular molybdenum trioxide, MoO3) The content of metal from group VIb, in particular molybdenum, expressed by weight of (A) is advantageously between 1% and 30% by weight, preferably between 4% and 20% by weight. The metal content is expressed as a weight percentage of metal oxide relative to the weight of the entrained supported catalyst.
Advantageously, the entrained supported catalyst may additionally comprise at least one dopant selected from phosphorus, boron and halogens (newly defined group VIIa or group 17 of the periodic table of the elements), preferably phosphorus.
In one embodiment of the process according to the invention, in particular in an ebullated bed reactor, each reactor of the hydroconversion step a) may use a different catalyst suitable for the feedstock sent to that reactor.
In one embodiment of the process according to the invention, several different types of catalysts can be used in each reactor.
In a preferred embodiment, each reactor of step a) may comprise one or more catalysts suitable for operating as an ebullating bed, and optionally one or more additional entrained catalysts.
According to the conventional art (described in the prior art, for example FR 3033797), the used hydroconversion catalyst can be partially replaced by fresh catalyst by withdrawing, preferably at the bottom of the reactor and introducing fresh catalyst into the reactor. The fresh catalyst can be replaced, in whole or in part, by used catalyst and/or regenerated (coke-free) catalyst and/or renewed catalyst (regenerated catalyst to which a compound that increases the activity of the catalyst has been added) and/or reactivated catalyst via extraction of poisons and inhibitors (e.g. deposited metals resulting from hydrodemetallization) and removal of coke formed.
Optional separation step b)
The process preferably proceeds to step b).
At least a portion, preferably all, of the effluent resulting from hydroconversion step a) may be subjected to one or more separation steps.
The separation step is carried out in order to separate at least one light fraction ("first light fraction") from the effluent, thereby obtaining at least one heavy liquid fraction at least 80% by weight of which has a boiling point of at least 250 ℃, preferably at least 300 ℃.
The light fraction may then be sent, at least in part, to a fractionation section where it is then passed, for example, by flowing through a flash drum with light gas (H)2And C1-C4) Advantageously separated. The hydrogen is recovered and then advantageously recycled to the inlet of the deep hydroconversion step a) or sent to the deep hydroconversion step c) and/or to other units of the refinery. The light liquid fraction separated from the light gas can then advantageously be passed to a fractionation section d). The light liquid fraction thus separated comprises dissolved light gases, naphtha (fraction boiling at a temperature below 150 ℃), kerosene (fraction boiling at 150 ℃ -250 ℃) and at least a portion of gas oil boiling at 250 ℃ -375 ℃.
The heavy liquid fraction resulting from step b) comprises compounds boiling at 250 ℃, preferably 300 ℃ or more, especially those boiling at temperatures of 375 ℃ to less than 540 ℃ (vacuum distillate) and those boiling at temperatures of 540 ℃ or more (corresponding to the vacuum residue (which is the unconverted fraction)). Thus, it may comprise a portion of the gas oil fraction, i.e. compounds boiling in the range of 250 ℃ to 375 ℃.
Said heavy liquid fraction is sent, in whole or in part, to a hydroconversion step c).
The separation step may be carried out by any separation means known to the person skilled in the art. Preferably, the separation step b) is carried out by means of one or more flash tanks in series, preferably by means of only one flash tank. Preferably, the flash tank is operated at a pressure and temperature close to the operating conditions of the last reactor of the hydroconversion step a).
In another embodiment, the separation step is carried out by means of a set of several flash tanks operating at different operating conditions from those of the last reactor of the hydroconversion step a), and several light liquid fractions may be obtained. The several light liquid fractions may then be sent in whole or in part to a fractionation section.
In another embodiment, the separation step is carried out by one or more steam stripping columns and/or hydrogen stripping (entrainment) columns. In this way, the effluent resulting from hydroconversion step a) will be separated into a light fraction and a heavy liquid fraction.
In another embodiment, the separating step is carried out by an atmospheric distillation column only, or by an atmospheric distillation column followed by a vacuum distillation column.
The separation step may also be a combination of these different embodiments.
Optionally, the heavy liquid fraction may be subjected to a step of separating out compounds having a boiling point of 540 ℃ or less, before it is sent to the hydroconversion step c) according to the invention. At least 80 wt% of the heavy fraction obtained has a boiling point of at least 540 ℃. The separation may be carried out by steam stripping and/or hydrogen stripping using one or more stripping columns.
Second deep hydroconversion (step c)
The liquid effluent resulting from step a) or the heavy fraction resulting from the separation step b) is subjected to a deep hydroconversion in step c). The effluent or the fraction may or may not be recycled to step a). Step a) and step c) are different steps carried out in different zones.
The range of operating conditions (interval) used, the catalyst are those described for step a).
The operating conditions of step c) are the same as or different from those of step a).
According to the invention, the total Hourly Space Velocity (HSV), i.e. the flow rate of the liquid feedstock of hydroconversion step a) at standard temperature and standard pressure conditions divided by the total volume of the reactors of step a) and step c), is less than 0.1h-1And is usually at least 0.05h-1Preferably 0.05h-1To 0.09h-1。
Fractionation step d)
Subsequently subjecting all or part of the effluent resulting from hydroconversion step c) to a fractionation step d). The fractionation may be carried out by one or more flash drums in series, preferably by a set of at least two successive flash drums, preferably by one or more steam strippers and/or hydrogen strippers, more preferably by an atmospheric distillation column and a vacuum column for atmospheric residue, more preferably by one or more flash drums, atmospheric distillation columns and vacuum columns for atmospheric residue. The fractionation may also be carried out by a combination of the different separation means described above.
The fractionation step is carried out with the aim of separating light gases and economically valuable distillates (gasoline, gas oil) so as to obtain at least one heavy liquid fraction in which at least 80% by weight boils at least 300 ℃, or at least 350 ℃, advantageously at least 375 ℃, or at least 400 ℃, or at least 450 ℃, or at least 500 ℃, preferably a residual fraction in which at least 80% by weight boils at least 540 ℃ or more. Preferably, the vacuum residue is separated (first by atmospheric distillation and then vacuum distillation of the atmospheric residue), which residue has an initial boiling point of 540 ℃.
Deasphalting step e)
According to the process according to the invention, said heavy liquid fraction obtained in step d) and said residual fraction thereof are subsequently subjected to a deasphalting step e) to obtain a deasphalted hydrocarbon fraction, known as DAO, and asphalt.
The deasphalting is generally carried out at a temperature of from 60 ℃ to 250 ℃ using at least one hydrocarbon solvent having from 3 to 7 carbon atoms; preferably, the solvent is butane, pentane or hexane, and mixtures thereof, optionally with the addition of at least one additive. The solvent/feedstock ratio (v/v) in deasphalting is generally from 4/1 to 9/1, and generally from 4/1 to 8/1.
Solvents and additives that can be used are broadly described. The recovery of the solvent can also and advantageously be carried out according to the optical method, i.e. by using the solvent under supercritical conditions in the separation section. The process in particular makes it possible to significantly improve the overall economics of the process. The deasphalting can be carried out in one or more mixer-settlers or in one or more extraction columns.
Techniques using at least one extraction column, and preferably only one extraction column, can be employed (e.g., SolvahlTMProcess).
Deasphalting unit producing almost no C7The deasphalted hydrocarbon fraction DAO of asphaltenes (also called deasphalted oil or deasphalted raffinate) and the residual bitumen, in which most of the impurities of the residual oil are concentrated and which are discharged.
The yield of DAO is generally from 40% to 90% by weight, depending on the quality of the heavy liquid fraction sent, the operating conditions and the solvent used.
The following table gives the range of typical operating conditions for deasphalting as a function of solvent:
solvent(s)
Propane
Butane
Pentane (pentane)
Hexane (C)
Heptane (Heptane)
Pressure, MPa
3 - 4
3 - 4
2 - 4
2 - 4
2 - 4
Temperature, C
45 - 90
80 - 130
140 - 210
150 - 230
160 - 250
Solvent/feedstock ratio, volume/volume
6 - 10
5 - 8
3 - 6
3 - 6
3 - 5
The conditions of deasphalting are adapted to the quality of the DAO to be obtained and to the feedstock entering the deasphalting.
These conditions allow a significant reduction in the Conradson carbon residue and C7Asphaltene content. The deasphalted hydrocarbon fraction DAO obtained advantageously has a content of less than 0.5% by weight, preferably less than 0.1% by weight, better still less than 0.08% by weight, or less than 0, relative to the total weight of said fraction.07% by weight of C7Asphaltene content.
In one embodiment, all or preferably a portion of said deasphalted fraction DAO is recycled to step a) and/or step c).
Conversion of the DAO fraction (step f)
The DAO fraction can be sent in whole or in part to an additional conversion step f). Preferably, the DAO is sent directly to the conversion step. Preferably, the entire DAO fraction is sent directly to the conversion step, that is to say it is not subjected to any treatment except for the optional fractionation step or steps.
This step allows the conversion of the process to reach very high levels (with respect to the 540 ℃ C. + fraction) and most often to reach more than 90%. The conversion method realized in the step is fixed bed hydrocracking, fluidized bed catalytic cracking FCC or fluidized bed hydroconversion (H-Oil DC); these conversion processes may be preceded by hydrotreating.
If desired, the deasphalted hydrocarbon fraction DAO can be subjected to an atmospheric distillation, optionally followed by a distillation under reduced pressure, in particular in the case in which step c) does not comprise a distillation.
The fractions obtained with economically valuable products are a gasoline fraction (150 ℃ C.), one or more middle distillate fractions (150 ℃ C.) and one or more heavier fractions boiling at 375 ℃ or more.
Preferably, said heavier fraction or fractions are sent to the conversion step f).
The characteristics of this fraction are particularly advantageous (low Conradson carbon content, low C)7Asphaltene content, low S content, low metal content).
In one embodiment, the deasphalted hydrocarbon fraction DAO is advantageously distilled as a mixture with at least part and preferably all of the light liquid fraction resulting from step b).
In another embodiment, the mixture can be sent to the conversion step f) without prior fractionation (distillation).
For distillation, the DAO may also have been mixed with a feedstock external to the process, such as a vacuum distillate, atmospheric residue, or vacuum residue fraction produced from a refinery's primary fractionation.
The process is preferably carried out without distillation. The DAO fraction (partially or totally) is then sent as such to step f).
The conversion step may be fixed bed hydrocracking. It can advantageously be carried out in one or more reactors or only in one reactor comprising one or more catalytic beds.
Fixed bed hydrocracking uses an acidic catalyst in the presence of hydrogen.
The presence of nitrogen and other impurities in the mixture requires prior pretreatment to prevent catalyst deactivation. Thus, it is common to use at least one fixed bed with hydrotreating catalyst followed by at least one fixed bed with hydrocracking catalyst. These catalysts are well known to those skilled in the art. Preferably, one of the catalysts described in patents EP B113297 and EP B113284 by the applicant company can be used.
The catalyst comprises at least one non-noble metal element from group VIII (Ni and/or Co) and at least one element from group VIb (Mo and/or W). The content of elements from group VIII is advantageously between 1% and 10% by weight of oxide, preferably between 1.5% and 9% by weight, very preferably between 2% and 8% by weight, relative to the total weight of the catalyst. The content of elements from group VIb is advantageously between 5% and 40% by weight of oxide, preferably between 8% and 37% by weight, very preferably between 10% and 35% by weight, relative to the total weight of the catalyst. Said contents being expressed with respect to the total weight of the catalyst.
The support for the hydroprocessing catalyst is typically alumina; the support for the hydrocracking catalyst typically comprises one or more zeolites (most commonly zeolite Y or zeolite beta), typically in admixture with alumina and/or silica/alumina. The weight content of zeolite is generally less than 80% by weight.
The hydrotreating catalyst and hydrocracking catalyst may also comprise at least one organic additive.
This operation is preferably carried out at an absolute pressure of between 5MPa and 35MPa, preferably between 10MPa and 20MPa, at a temperature advantageously ranging from 300 ℃ to 500 ℃, preferably from 350 ℃ to 450 ℃. The HSV and hydrogen partial pressures are chosen according to the nature of the feedstock to be treated and the desired conversion. Preferably, HSV is 0.1h-1To 5h-1Preferably 0.15h-1To 2h-1. The amount of hydrogen advantageously mixed with the feedstock is preferably 100Sm3/m3-1000Sm3/m3Liquid feedstock, preferably 500S m3/m3-3000Sm3/m3。
The ebullated bed hydroconversion step (H-Oil DC) to treat the DAO fraction may advantageously be carried out at an absolute pressure of from 2MPa to 35MPa, preferably from 5MPa to 25MPa, preferably from 6MPa to 20MPa, at a temperature of from 300 ℃ to 550 ℃, preferably from 350 ℃ to 500 ℃, preferably from 380 ℃ to 470 ℃, more preferably from 400 ℃ to 450 ℃. The amount of hydrogen advantageously mixed with the feedstock is preferably 50Sm at standard temperature and standard pressure conditions3/m3-5000Sm3/m3Liquid feedstock, preferably 100Sm3/m3-2000Sm3/m3Very preferably 200Sm3/m3-1000Sm3/m3. Preferably, the HSV of this step is 0.1h-1To 10h-1Preferably 0.15h-1To 5h-1。
The hydroconversion catalyst used in the ebullating bed comprises one or more elements from
Advantageously, the hydroconversion catalyst is a catalyst comprising an alumina support and at least one group VIII metal selected from nickel and cobalt, preferably nickel, and at least one group VIb metal selected from molybdenum and tungsten; preferably, the group VIb metal is molybdenum. Preferably, the hydroconversion catalyst comprises nickel and molybdenum.
The nickel content, expressed as weight of nickel oxide (NiO), is advantageously between 0.5% and 10% by weight, preferably between 1% and 6% by weight, and in molybdenum trioxide (MoO)3) The molybdenum content expressed by weight of (a) is advantageously between 1% and 30% by weight, preferably between 4% and 20% by weight. Said contents being expressed with respect to the total weight of the catalyst.
The catalyst is advantageously used in the form of extrudates or beads. The extrudate has a diameter of, for example, 0.5mm to 2.0mm and a length of 1mm to 5 mm. These catalysts are well known to those skilled in the art.
According to the conventional art (described in the prior art, for example in FR 3033797), the used hydroconversion catalyst can be partially replaced by fresh catalyst by withdrawing, preferably at the bottom of the reactor and introducing fresh catalyst into the reactor. The fresh catalyst can be replaced, in whole or in part, by used catalyst and/or regenerated (coke-free) catalyst and/or renewed catalyst (regenerated catalyst to which a compound that increases the activity of the catalyst has been added) and/or reactivated catalyst via extraction of poisons and inhibitors (e.g. deposited metals resulting from hydrodemetallization) and removal of coke formed.
The effluent resulting from the conversion step f) is then generally distilled to recover economically valuable gasoline and gas oil fractions. The residual unconverted fraction may be recycled to one of the steps of the process.
In another embodiment, the conversion step f) may be carried out by a fluid catalytic cracking unit. The DAO may be treated by co-processing with one or more heavy feeds of VGO, HDT VGO or resid type or separately.
The fluid catalytic cracking unit may comprise only one reactor handling heavy feedstock and DAO or only DAO, or two completely different reactors, one reactor handling heavy feedstock and the other reactor handling DAO. Further, each reactor may be an upflow reactor or a downflow reactor. Most often, both reactors have the same flow pattern.
When catalytic cracking is carried out by co-processing one or more heavy feedstocks and DAO:
1) in a single upflow reactor, the Reactor Outlet Temperature (ROT) is from 450 ℃ to 650 ℃, preferably from 470 ℃ to 620 ℃, and the C/O ratio is from 2 to 20, preferably from 4 to 15.
2) In a single downflow reactor, the Reactor Outlet Temperature (ROT) is 480 ℃ to 650 ℃ and the C/O ratio is 10 to 50.
3) The first reactor, which carries out the cracking of the heavy feedstock or feedstocks, is operated at a reactor outlet temperature (ROT1) ranging from 450 ℃ to 650 ℃, preferably from 470 ℃ to 620 ℃, with a C/O ratio ranging from 2 to 20, preferably from 4 to 15, in two completely different upflow reactors. The second reactor, which carries out the cracking of DAO, is operated at a reactor outlet temperature (ROT2) ranging from 500 ℃ to 600 ℃, preferably from 520 ℃ to 580 ℃, with a C/O ratio ranging from 2 to 20.
4) The first FCC reactor, which carries out the cracking of one or more heavy feedstocks, operates at a reactor outlet temperature (ROT1) ranging from 480 ℃ to 650 ℃ in two completely different downflow FCC reactors, with a C/O ratio ranging from 10 to 50. The second FCC reactor, which carries out the cracking of DAO, operates at a reactor outlet temperature (ROT2) ranging from 570 ℃ to 600 ℃ with a C/O ratio ranging from 10 to 50.
When catalytic cracking of DAO is carried out only:
1) in an upflow reactor, the reactor is operated at a Reactor Outlet Temperature (ROT) of from 500 ℃ to 600 ℃, preferably from 520 ℃ to 580 ℃, with a C/O ratio of from 2 to 20.
2) In a downflow reactor, the reactor is operated at a reactor outlet temperature (ROT2) of 570 ℃ to 600 ℃ with a C/O ratio of 10 to 50.
The spent catalyst streams produced by the two FCC reactors are separated from the cracked effluent by any gas/solid separation system known to those skilled in the art and regenerated in a common regeneration zone.
The effluent from the catalytic cracking reactor (or both if there are two reactors) is sent to a fractionation zone. The separation unit typically includes an initial separation of the effluent, which may result in, among other things, economically valuable fractions such as gasoline, middle distillate and heavy distillate fractions. The remaining unconverted fraction can be recycled to one of the steps of the process.
The catalyst of the fluid catalytic cracking step is typically composed of particles having an average diameter typically in the range of 40 microns to 140 microns and most often in the range of 50 microns to 120 microns.
The catalytic cracking catalyst comprises at least one suitable matrix, such as alumina, silica or silica/alumina, in which Y-zeolite is dispersed or in which no Y-zeolite is dispersed.
The catalyst may additionally comprise at least one zeolite exhibiting shape selectivity having one of the following structure types: MEL (e.g., ZSM-11), MFI (e.g., ZSM-5), NES, EOU, FER, CHA (e.g., SAPO-34), MFS, or MWW. It may also comprise one of the following zeolites: NU-85, NU-86, NU-88 and IM-5, which also exhibit shape selectivity.
The advantage of these zeolites exhibiting shape selectivity is to obtain a better propylene/isobutylene selectivity in the cracked effluent, i.e. a higher propylene/isobutylene ratio.
The proportion of zeolite exhibiting shape selectivity relative to the total amount of zeolite may vary depending on the structure of the starting material used and the desired product. Zeolites exhibiting shape selectivity are generally used in amounts of from 0.1% to 60% by weight, preferably from 0.1% to 40% by weight, in particular from 0.1% to 30% by weight.
One or more zeolites can be dispersed in a matrix based on silica, alumina or on silica/alumina, the proportion of zeolite (combination of all zeolites) generally ranging from 0.7% to 80% by weight, preferably from 1% to 50% by weight and more preferably from 5% to 40% by weight, relative to the weight of the catalyst.
In the case where several zeolites are used, they may be incorporated into only one matrix or several different matrices. The zeolite exhibiting shape selectivity is present in an amount of less than 30 wt% of the total inventory.
The catalyst used in the catalytic cracking reactor may comprise a Y-type ultrastable zeolite dispersed in an alumina, silica or silica/alumina matrix to which is added an additive based on zeolite ZSM5, the ZSM5 crystals being present in an amount of less than 30 wt% of the total inventory.
Drawings
Figure 1 illustrates the present invention.
Comprising a deep hydroconversion section a in which a deep hydroconversion step a) is carried out. The feedstock 1 is converted in the presence of
Example (b):
example 1 and example 2 were compared at the same conversion (75% conversion from 540 ℃ + to 540 ℃) and example 3 and example 4 were carried out at the same temperature. Example 5 and example 6 were compared at the same conversion (75% conversion from 540 ℃ + to 540 ℃) and example 7 and example 8 were carried out at the same temperature.
Raw materials
The heavy feedstock is a Vacuum Residue (VR) produced from Urals crude oil, the main characteristics of which are listed in table 1 below. For the different examples, this VR heavy feed is the same fresh feed.
Table 1: composition of process feedstock
Raw material of step (2)
A
Raw materials
Urals VR
Density of
1.000
Content of 540 ℃ +
By weight%
77.9
Viscosity at 100 deg.C
cSt
880
Conradson carbon residue
By weight%
17.0
C7Asphaltenes
By weight%
6.8
Nickel + vanadium
ppm
233
Nitrogen is present in
ppm
6010
Sulfur
By weight%
2.715
Not according to example 1 of the invention:with high hourly space velocity and high temperature (total HSV 0.3 h)-1+431/431 deg.C) + scheme for deasphalting Step (SDA)
In this example, two ebullated-bed reactors (a first deep hydroconversion section and a second deep hydroconversion section) are arranged in series, operating at high Hourly Space Velocity (HSV) and high temperatures, with an interstage separation section and a downstream deasphalting process.
Hydroconversion section A
The fresh feeds of Table 1 were all fed in the presence of hydrogen to a first ebullated bed hydroconversion section A comprising a three-phase reactor containing a catalyst having a NiO content of 4 wt% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
Table 2 lists the conditions applied in hydroconversion section a.
Table 2: operating conditions of the hydroconversion section A
Segment of
A
Total P
MPa
16
Temperature of
℃
431
Amount of hydrogen
Sm3/m3
500
These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section B
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section C
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
Table 4 lists the conditions used in hydroconversion section C.
Table 4: operating conditions of the hydroconversion section C
Segment of
C
Total P
MPa
15.6
Temperature of
℃
431
Amount of hydrogen
Sm3/m3
300
Fractionation section D
The effluent from the hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 5 below.
Table 5: yield and quality of VR from fractionation stage D
Fraction (b) of
Unconverted vacuum residue
Yield relative to fresh feed (A)
By weight%
19.42
Content of 540 ℃ +
By weight%
100
Density of
g/cm3
1.0157
Conradson carbon residue
By weight%
22.2
Nickel + vanadium
ppm
91.4
Nitrogen is present in
ppm
8870
Sulfur
By weight%
1.028
Saturated compounds
By weight%
15.5
Aromatic compound
By weight%
36.2
Resin composition
By weight%
38.9
C7Asphaltenes
By weight%
9.4
Deasphalting section E
The vacuum residue resulting from stage D is sent to deasphalting stage E.
The conditions applied in the deasphalting unit are described in table 6.
Table 6: operating conditions in SDA Unit E
Raw materials
Vacuum residuum from stage D
Solvent(s)
Butane
Pressure of the extractor
MPa
3.0
Extractor TAverage
℃
95
Solvent/feedstock ratio
Volume/
8
At the end of the E-section, a DAO fraction is obtained which is economically valuable in conversion processes (fixed bed hydrocracking, FCC or recycle to hydroconversion processes in ebullating beds under mild conditions) and a "pitch" fraction which is economically difficult to value. Table 7 lists the yields and qualities of these two products.
Table 7: yield and quality of the effluent resulting from the deasphalting section E
Fraction (b) of
DAO
Asphalt
Yield relative to unconverted VR (D)
By weight%
49.9
50.1
Yield relative to fresh feed (A)
By weight%
9.7
9.7
Density of
g/cm3
0.9474
1.0942
Conradson carbon residue
By weight%
7.42
36.9
C7Asphaltenes
By weight%
0.09
18.7
Nickel + vanadium
ppm
< 2
181
Nitrogen is present in
ppm
4520
13 210
Sulfur
By weight%
0.836
1.220
Quality of overall performance
With this scheme not according to the invention, for 0.3h-1The conversion of the heavy 540 c + fraction prior to the deasphalting step was 75.1 wt% for the total Hourly Space Velocity (HSV) and the high temperature (431/431 c). In addition, unconverted VR contains high levels of Conradson carbon residue and C7Asphaltenes (respectively)22.2 wt% and 9.4 wt%), which means that only 49.9 wt% of the unconverted VR can be recovered as DAO. Thus, this conventional scheme is accompanied by the production of a large amount of 9.7 wt.% pitch relative to the fresh starting material. If the DAO fraction is subsequently completely converted in the hydrocracking unit, the total conversion of the heavy 540 ℃ + fraction in the overall scheme is 87.5 wt%.
Example 2 according to the invention:with low hourly space velocity and low temperature (total HSV 0.089 h)-1+411/411 deg.C) + SDA protocol according to the invention
In this example, the invention is exemplified by a process scheme having two ebullated-bed reactors arranged in series, with the interstage separation section and the downstream deasphalting process, as described in connection with fig. 1, at low hourly space velocities (HSV =0.089 h)-1) And operation at low temperature (411/411 ℃ C.).
Hydroconversion section A
The fresh feeds of Table 1 were all fed in the presence of hydrogen to a first ebullated bed hydroconversion section A comprising a three-phase reactor containing a catalyst having a NiO content of 4 wt% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
Table 8 lists the conditions applied in hydroconversion section a.
Table 8: operating conditions of the hydroconversion section A
Segment of
A
Total P
MPa
16
Temperature of
℃
411
Amount of hydrogen
Sm3/m3
600
Separation section B
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section C
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Table 9 lists the conditions used in hydroconversion section C.
Table 9: operating conditions of the hydroconversion section C
Segment of
A
Total P
MPa
15.6
Temperature of
℃
411
Amount of hydrogen
Sm3/m3
250
Fractionation section D
The effluent from the hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 10 below.
Table 10: yield and quality of VR from fractionation stage D
Fraction (b) of
Unconverted vacuum residue
Yield relative to fresh feed (A)
By weight%
19.33
Content of 540 ℃ +
By weight%
100
Density of
g/cm3
0.9924
Conradson carbon residue
By weight%
16.4
Nickel + vanadium
ppm
21.7
Nitrogen is present in
ppm
7120
Sulfur
By weight%
0.687
Saturated compounds
By weight%
19.0
Aromatic compound
By weight%
41.6
Resin composition
By weight%
34.9
C7Asphaltenes
By weight%
4.6
Deasphalting section E
The vacuum residue resulting from stage D is sent to deasphalting stage E.
The conditions applied in the deasphalting unit are described in table 11.
Table 11: operating conditions in SDA Unit E
Raw materials
Vacuum residuum from stage D
Solvent(s)
Butane
Pressure of the extractor
MPa
3.0
Extractor TAverage
℃
95
Solvent/feedstock ratio
Volume/
8
At the end of the E-section, a DAO fraction is obtained which is economically valuable in conversion processes (fixed bed hydrocracking, FCC or recycle to hydroconversion processes in ebullating beds under mild conditions) and a "pitch" fraction which is economically difficult to value.
The yields and qualities of these two products are given in table 12.
Table 12: yield and quality of the effluent resulting from the deasphalting section E
Fraction (b) of
DAO
Asphalt
Yield relative to unconverted VR (D)
By weight%
68.2
31.8
Yield relative to fresh feed (A)
By weight%
13.2
6.1
Density of
g/cm3
0.9495
1.0988
Conradson carbon residue
By weight%
8.1
34.1
C7Asphaltenes
By weight%
0.07
14.2
Nickel + vanadium
ppm
< 2
67.4
Nitrogen is present in
ppm
4590
12 530
Sulfur
By weight%
0.610
0.849
Quality of overall performance
Using HSV with a total of 0.089h-1According to this variant of the invention, the conversion of the heavy 540 ℃ + fraction before the deasphalting step is 75.2% by weight, i.e.equivalent to example 1. However, compared to example 1, the unconverted VR contained a lower content of Conradson carbon residue and C7Asphaltenes, which can recover more DAO from unconverted VR (68.2 wt% recoverable in this example, and 49.9 wt% recoverable in example 1). This variant according to the invention is therefore accompanied by a lower bitumen production (corresponding to 6.1% by weight) relative to the fresh starting material. If all the DAO is converted in the hydrocracking unit, by this example according to the invention, it is thus possible to obtain a total conversion of the initial heavy 540 ℃ + fraction of 92.1 wt%, i.e. 4.6% higher conversion percentage points than in example 1. Thus, a conversion in excess of 90% by weight with respect to the fresh feed can be obtained according to the solution of the invention.
Not according to
In this example, this operation was carried out using two ebullated-bed reactors (first and second deep hydroconversion) arranged in series, operating at high Hourly Space Velocity (HSV) and medium temperature (420 ℃), with an inter-step separation section, and a downstream deasphalting process.
Hydroconversion section A
The fresh feeds of table 1 were all fed to the ebullated bed hydroconversion section a in the presence of hydrogen. The three-phase reactor contained a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
Table 13 lists the conditions used in hydroconversion section a.
Table 13: operating conditions of the hydroconversion section A
Segment of
A
Total P
MPa
16
Temperature of
℃
420
Amount of hydrogen
Sm3/m3
350
These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section B
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section C
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, the percentages being relative to the catalystThe total weight of the agent. The section operates as an ebullated bed with an upflow of liquid and upflow of gas.
Table 14 lists the conditions used in hydroconversion section C.
Table 14: operating conditions of the hydroconversion section C
Segment of
A
Total P
MPa
15.6
Temperature of
℃
420
Amount of hydrogen
Sm3/m3
200
Fractionation section D
The effluent from hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 15 below.
Table 15: yield and quality of VR from fractionation stage D
Fraction (b) of
Unconverted vacuum residue
Yield relative to fresh feed (A)
By weight%
31.75
Content of 540 ℃ +
By weight%
100
Density of
g/cm3
1.0098
Conradson carbon residue
By weight%
20.7
Nickel + vanadium
ppm
98.0
Nitrogen is present in
ppm
8230
Sulfur
By weight%
1.246
Saturated compounds
By weight%
16.4
Aromatic compound
By weight%
37.5
Resin composition
By weight%
37.9
C7Asphaltenes
By weight%
8.2
Deasphalting section E
The vacuum residue resulting from stage D is sent to deasphalting stage E.
The conditions applied in the deasphalting unit are described in table 16.
Table 16: operating conditions in SDA Unit E
Raw materials
Vacuum residuum from stage D
Solvent(s)
Butane
Pressure of the extractor
MPa
3.0
Extractor TAverage
℃
95
Solvent/feedstock ratio
Volume/
8
At the end of the E-section, a DAO fraction is obtained which is economically valuable in the conversion process (hydrocracking, FCC or recycling to the hydroconversion process) and a "bitumen" fraction which is economically difficult to value. The yields and qualities of these two products are given in table 17.
Table 17: yield and quality of the effluent resulting from the deasphalting section E
Fraction (b) of
DAO
Asphalt
Yield relative to unconverted VR
By weight%
54.1
45.9
Yield relative to fresh feed (A)
By weight%
17.2
14.6
Density of
g/cm3
0.9478
1.0943
Conradson carbon residue
By weight%
7.53
36.3
C7Asphaltenes
By weight%
0.08
17.8
Nickel + vanadium
ppm
< 2
212.4
Nitrogen is present in
ppm
4420
12 730
Sulfur
By weight%
1.036
1.493
Quality of overall performance
With this scheme, for 0.3h-1The conversion of the heavy 540 c + fraction before the deasphalting step was 59.2 wt% for total Hourly Space Velocity (HSV) and medium temperature (420/420 c). In addition, unconverted VR contains high levels of Conradson carbon residue and C7Asphaltenes (20.7 wt% and 8.2 wt%, respectively) mean that only 54.1 wt% of unconverted VR can be recovered as DAO. Thus, this conventional scheme is accompanied by the production of large amounts of pitch of 14.6 wt.% relative to the fresh starting material. This solution according to the prior art corresponds only to an overall conversion of the initial heavy 540 ℃ + fraction of 81.3% by weight, even if all the DAO is converted in the hydrocracking unit. Thus, it is not possible to achieve conversion levels of the heavy 540 ℃ + fraction of more than 90 wt%.
Example 4 according to the invention:with low hourly space velocity and low temperature (total HSV 0.089 h)-1+420/420 deg.C) + SDA deasphalting step protocol according to the invention
In this example, the invention is illustrated according to the scheme of fig. 1, using a process scheme with two ebullated-bed reactors arranged in series, at low hourly space velocities (HSV =0.089 h), and an interstage separation section and a downstream deasphalting process-1) And at moderate temperature (420/420 ℃).
Hydroconversion section A
The fresh feeds of table 1 were all fed to the ebullated bed hydroconversion section a in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 18 lists the conditions used in hydroconversion section a.
Table 18: operating conditions of the hydroconversion section A
Segment of
A
Total P
MPa
16
Temperature of
℃
420
Amount of hydrogen
Sm3/m3
700
These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section B
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section C
In this reference scheme, the heavy fraction produced by the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. Said section comprising a three-phase reactor, the reactionThe container contained a composition having a NiO content of 4 wt.% and a MoO content of 9 wt.%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 19 lists the conditions used in hydroconversion section C.
Table 19: operating conditions of the hydroconversion section C
Segment of
A
Total P
MPa
15.6
Temperature of
℃
420
Amount of hydrogen
Sm3/m3
350
Fractionation section D
The effluent from hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 20 below.
Table 20: yield and quality of VR produced in fractionation stage D
Fraction (b) of
Unconverted vacuum residue
Yield relative to fresh feed (A)
By weight%
10.8
Content of 540 ℃ +
By weight%
100
Density of
g/cm3
0.9952
Conradson carbon residue
By weight%
17.05
Nickel + vanadium
ppm
19.4
Nitrogen is present in
ppm
7350
Sulfur
By weight%
0.582
Saturated compounds
By weight%
18.5
Aromatic compound
By weight%
41.4
Resin composition
By weight%
35.4
C7Asphaltenes
By weight%
4.8
Deasphalting section E
The vacuum residue resulting from stage D is sent to deasphalting stage E. The conditions applied in the deasphalting unit are described in table 21.
Table 21: operating conditions in SDA Unit E
Raw materials
Vacuum residuum from stage D
Solvent(s)
Butane
Pressure of the extractor
MPa
3.0
Extractor TAverage
℃
95
Solvent/feedstock ratio
Volume/
8
At the end of the E-section, a DAO fraction is obtained which is economically valuable in the conversion process (hydrocracking, FCC or recycling to the hydroconversion process) and a "bitumen" fraction which is economically difficult to value. Table 22 lists the yields and qualities of these two products.
Table 22: yield and quality of the effluent resulting from the deasphalting section E
Fraction (b) of
DAO
Asphalt
Yield relative to unconverted VR
By weight%
66.8
33.2
Yield relative to fresh feed (A)
By weight%
7.2
3.6
Density of
g/cm3
0.9505
1.0995
Conradson carbon residue
By weight%
8.3
34.6
C7Asphaltenes
By weight%
0.07
14.2
Nickel + vanadium
ppm
< 2
57.9
Nitrogen is present in
ppm
4670
12 750
Sulfur
By weight%
0.515
0.716
Quality of overall performance
With a total HSV of 0.089h according to the invention-1And with a medium temperature (420/420 c), the conversion of the heavy 540 c + fraction before the deasphalting step was 86.1 wt%, i.e. 26.9 wt% higher than in example 3 at the same temperature level. Thus, the amount of unconverted VR recovered in example 4 was reduced to about 1/3. Furthermore, the unconverted VR of example 4 contains lower amounts of conradson carbon and C than example 37Asphaltenes, which can recover more DAO from unconverted VR (66.8 wt% recoverable in this example, and 54.1 wt% recoverable in example 3). This variant according to the invention is therefore accompanied by the production of a minor amount of bitumen of only 3.6% by weight with respect to the fresh starting material. If all DAO is converted in the hydrocracking unit, a very high conversion of the initial heavy 540 ℃ + fraction of 95.4 wt% can therefore be obtained by this scheme according to the invention.
Not according to example 5 of the invention:with high hourly space velocity and high temperature (total HSV 0.3 h)-1+431/431 ℃) + deasphalting Step (SDA) + DAO conversion step in FCC protocol
In this example, two ebullated-bed reactors (a first deep hydroconversion section and a second deep hydroconversion section) are arranged in series, operating at high Hourly Space Velocity (HSV) and high temperatures, with an interstage separation section and a downstream deasphalting process. The DAO fraction is subsequently converted in an FCC unit.
Hydroconversion section (A)
The fresh feeds of Table 1 were all fed in the presence of hydrogen to a first ebullated bed hydroconversion section A comprising a three-phase reactor containing a catalyst having a NiO content of 4 wt% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 2 showsThe conditions applied in hydroconversion section a are described. These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section (B)
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section (C)
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 4 lists the conditions used in hydroconversion section C.
Fractionation section (D)
The effluent from the hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to the fresh feedstock being given in table 5.
Deasphalting section (E)
The vacuum residue resulting from stage D is sent to deasphalting stage E. The conditions applied in the deasphalting unit are described in table 6. At the end of the E section, a DAO fraction and an economically unattractive "bitumen" fraction are obtained. Table 7 lists the yields and qualities of these two products.
DAO conversion section (F)
The DAO fraction resulting from the deasphalting section E is subsequently sent to a fluid catalytic cracking unit, also known as FCC unit. The conversion unit can convert the DAO fraction (which is the 540 ℃ + fraction) into a lighter fraction. This can therefore increase the overall conversion of the starting feedstock (vacuum residue (VR) produced from Urals crude, the characteristics of which are listed in table 1). On the other hand, as shown in table 23, the liquid fraction produced by the FCC unit still contained a small amount of unconverted 540 ℃ + fraction, with a yield of 1.1 wt% with respect to the FCC feedstock. In contrast to example 1, where all DAO was converted in the hydrocracking unit, the DAO in this example was not all converted.
Table 23: yield and quality of effluent produced from FCC unit F
Unit cell
FCC
Gasoline (C)5Yield-220 ℃ C.)
By weight%
40.9
Gas oil (220-360 ℃) yield
By weight%
14.2
Yield of vacuum distillate (360 ℃ -540 ℃)
By weight%
14.2
Yield of vacuum residue (540 ℃ C. +)
By weight%
1.1
Quality of overall performance
With this scheme not according to the invention, for 0.3h-1The conversion of the heavy 540 c + fraction prior to the deasphalting step was 75.1 wt% for the total Hourly Space Velocity (HSV) and the high temperature (431/431 c). Unconverted VR contains high levels of Conradson carbon residue and C7Asphaltenes (22.2 wt% and 9.4 wt%, respectively) mean that only 49.9 wt% of unconverted VR can be recovered as DAO. Thus, this conventional scheme is accompanied by the production of a large amount of 9.7 wt.% pitch relative to the fresh starting material. Under this example, the DAO fraction was converted in an FCC unit. With this successive scheme not according to the invention, for 0.30h-1For total Hourly Space Velocity (HSV) and high temperature (431/431 ℃), the total conversion of the heavy 540 ℃ + fraction in the entire scheme was 86.8 wt%.
Example 6 according to the invention:with low hourly space velocity and low temperature (total HSV 0.089 h)-1+411/411 ℃) + deasphalting Step (SDA) + conversion step of DAO in FCC protocol according to the invention
In this example, the invention is exemplified by a process scheme having two ebullated-bed reactors arranged in series, with the interstage separation section and the downstream deasphalting process, as described in connection with fig. 1, at low hourly space velocities (HSV =0.089 h)-1) And operation at low temperature (411/411 ℃ C.). The DAO fraction is subsequently converted in an FCC unit.
Hydroconversion section (A)
The fresh feeds of Table 1 were all fed in the presence of hydrogen to a first ebullated bed hydroconversion section A comprising a three-phase reactor containing a catalyst having a NiO content of 4 wt% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 8 lists the conditions applied in hydroconversion section a.
Separation section(B)
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section (C)
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content. Table 9 lists the conditions used in hydroconversion section C.
Fractionation section (D)
The effluent from the hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to the fresh feedstock being given in table 10.
Deasphalting section (E)
The vacuum residue resulting from stage D is sent to deasphalting stage E. The conditions applied in the deasphalting unit are described in table 11. At the end of the E section, a DAO fraction and an economically unattractive "bitumen" fraction are obtained. Table 12 lists the yields and qualities of these two products.
DAO conversion section (F)
The DAO fraction resulting from the deasphalting section E is subsequently sent to a fluid catalytic cracking unit, also known as FCC unit. The conversion unit can convert the DAO fraction (which is the 540 ℃ + fraction) into a lighter fraction. This can therefore increase the overall conversion of the starting feedstock (vacuum residue (VR) produced from Urals crude, the characteristics of which are listed in table 1). On the other hand, as shown in table 24, the liquid fraction produced by the FCC unit still contained a small amount of unconverted 540 ℃ + fraction, with a yield of 1.2 wt% with respect to the FCC feedstock. In contrast to example 2, where all DAO was converted in the hydrocracking unit, the DAO in this example was not all converted.
Table 24: yield and quality of effluent produced from FCC unit F
Unit cell
FCC
Gasoline (C)5Yield-220 ℃ C.)
By weight%
41.6
Gas oil (220-360 ℃) yield
By weight%
14.3
Yield of vacuum distillate (360 ℃ -540 ℃)
By weight%
15.2
Yield of vacuum residue (540 ℃ C. +)
By weight%
1.2
Quality of overall performance
Adopting HSV =0.089h with total hourly space velocity-1The conversion of the heavy 540 c + fraction before the deasphalting step according to the scheme of the invention was 75.2% by weight, i.e. comparable to example 5. However, compared to example 5, the unconverted VR contained a lower content of Conradson carbon residue and C7Asphaltenes, which can recover more DAO from unconverted VR (68.2 wt% recoverable in this example, and 49.9 wt% recoverable in example 5). This variant according to the invention is therefore accompanied by a lower bitumen production corresponding to 6.1% by weight with respect to the fresh starting material. In this example, the DAO fraction was converted in an FCC unit. With this successive scheme according to the invention, for 0.089h-1The total conversion of the heavy 540 c + fraction relative to the initial heavy 540 c + fraction in the overall scheme was 91.0 wt%, i.e., 4.2 percent higher conversion than in example 5, for both the total Hourly Space Velocity (HSV) and the low temperature (411/411 c). Thus, a conversion in excess of 90% by weight with respect to the fresh feed can be obtained according to the solution of the invention.
Not according to example 7 of the invention:has high hourly space velocity and medium temperature (total HSV 0.3 h)-1+420/420 ℃) + deasphalting Step (SDA) + DAO conversion step in FCC protocol
In this example, operation was carried out using two ebullated-bed reactors (first and second deep hydroconversion) arranged in series, operating at high Hourly Space Velocity (HSV) and medium temperature (420 ℃), with an inter-step separation section, and a downstream deasphalting process. The DAO fraction is subsequently converted in an FCC unit.
Hydroconversion section (A)
The fresh feeds of Table 1 were all fed to the ebullated bed hydroconversion section A in the presence of hydrogen, and the three-phase reactor contained a catalyst having a NiO content of 4 wt% and MoO content of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. As a section having an upflow of liquid and an upflowA bubbling bed of gas.
Table 13 lists the conditions used in hydroconversion section a. These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section (B)
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists mainly of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section (C)
The heavy fraction resulting from the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 14 lists the conditions used in hydroconversion section C.
Fractionation section (D)
The effluent from hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 15.
Deasphalting section (E)
The vacuum residue resulting from stage D is sent to deasphalting stage E. The conditions applied in the deasphalting unit are described in table 16. At the end of the E section, a DAO fraction and an economically unattractive "bitumen" fraction are obtained. Table 17 lists the yields and qualities of these two products.
DAO conversion section (F)
The DAO fraction resulting from the deasphalting section E is subsequently sent to a fluid catalytic cracking unit, also known as FCC unit. The conversion unit can convert the DAO fraction (which is the 540 ℃ + fraction) into a lighter fraction. This can therefore increase the overall conversion of the starting feedstock (vacuum residue (VR) produced from Urals crude, the characteristics of which are listed in table 1). On the other hand, as shown in table 25, the liquid fraction produced by the FCC unit still contained a small amount of unconverted 540 ℃ + fraction, with a yield of 1.9 wt% with respect to the FCC feedstock. In contrast to example 3, where all DAO was converted in the hydrocracking unit, the DAO in this example was not all converted.
Table 25: yield and quality of effluent produced from FCC unit F
Unit cell
FCC
Gasoline (C)5Yield-220 ℃ C.)
By weight%
30.9
Gas oil (220-360 ℃) yield
By weight%
16.7
Yield of vacuum distillate (360 ℃ -540 ℃)
By weight%
22.5
Yield of vacuum residue (540 ℃ C. +)
By weight%
1.9
Quality of overall performance
With this scheme, for 0.3h-1The conversion of the heavy 540 c + fraction before the deasphalting step was 59.2 wt% for total Hourly Space Velocity (HSV) and medium temperature (420/420 c). In addition, unconverted VR contains high levels of Conradson carbon residue and C7Asphaltenes (20.7 wt% and 8.2 wt%, respectively) mean that only 54.1 wt% of unconverted VR can be recovered as DAO. Thus, this conventional scheme is accompanied by the production of large amounts of pitch of 14.6 wt.% relative to the fresh starting material. In this example, the DAO fraction was converted in an FCC unit. With this successive scheme not according to the invention, for 0.30h-1For total Hourly Space Velocity (HSV) and medium temperature (420/420 ℃), the total conversion of the heavy 540 ℃ + fraction in the entire scheme was 80.0 wt%. Therefore, this solution according to the prior art does not make it possible to achieve conversion levels of the heavy 540 ℃ + fraction greater than 90% by weight.
Example 8 according to the invention:with low hourly space velocity and low temperature (total HSV 0.089 h)-1+420/420 ℃) + deasphalting Step (SDA) + conversion step of DAO in FCC protocol according to the invention
In this example, the invention is illustrated according to the scheme of fig. 1, using a process scheme with two ebullated-bed reactors arranged in series, at low hourly space velocities (HSV =0.089 h), and an interstage separation section and a downstream deasphalting process-1) And at moderate temperature (420/420 ℃). The DAO fraction is subsequently converted in an FCC unit.
Hydroconversion section (A)
The fresh feeds of table 1 were all fed to the ebullated bed hydroconversion section a in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, the percentages being relative toThe total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 18 lists the conditions used in hydroconversion section a. These operating conditions make it possible to obtain a liquid effluent with a reduced conradson carbon content, metal content and sulphur content.
Separation section (B)
The liquid effluent resulting from stage a is then sent to a separation stage B consisting of a single gas/liquid separator operating at the pressure and temperature of the reactor of the first hydroconversion stage a. From which a "light" fraction and a "heavy" fraction are separated. The "light" fraction consists mainly of molecules having a boiling point below 350 ℃ and the "heavy" fraction consists of hydrocarbon molecules boiling at a temperature of at least 350 ℃.
Hydroconversion section (C)
In this reference scheme, the heavy fraction produced by the separation section B is sent separately and in its entirety to the second ebullated bed hydroconversion section C in the presence of hydrogen. The stage comprised a three-phase reactor containing a catalyst having a NiO content of 4 wt.% and MoO of 9 wt%3Content of NiMo/alumina hydroconversion catalyst, said percentages being expressed with respect to the total weight of the catalyst. The section operates as an ebullated bed with an upflow of liquid and upflow of gas. Table 19 lists the conditions used in hydroconversion section C.
Fractionation section (D)
The effluent from hydroconversion section C is sent to a fractionation section D consisting of atmospheric distillation followed by vacuum distillation, from which an unconverted Vacuum Residue (VR) heavy fraction boiling at a temperature of at least 540 ℃ is recovered, the yields and their qualities with respect to fresh feedstock being given in table 20.
Deasphalting section (E)
The vacuum residue resulting from stage D is sent to deasphalting stage E. The conditions applied in the deasphalting unit are described in table 21. At the end of the E-section, a DAO fraction is obtained which is economically valuable in the conversion process (hydrocracking, FCC or recycling to the hydroconversion process) and a "bitumen" fraction which is economically difficult to value. Table 22 lists the yields and qualities of these two products.
DAO conversion section (F)
The DAO fraction resulting from the deasphalting section E is subsequently sent to a fluid catalytic cracking unit, also known as FCC unit. The conversion unit can convert the DAO fraction (which is the 540 ℃ + fraction) into a lighter fraction. This can therefore increase the overall conversion of the starting feedstock (vacuum residue (VR) produced from Urals crude, the characteristics of which are listed in table 1). On the other hand, as shown in table 26, the liquid fraction produced by the FCC unit still contained a small amount of unconverted 540 ℃ + fraction, with a yield of 1.2 wt% with respect to the FCC feedstock. In contrast to example 4, where all DAO was converted in the hydrocracking unit, the DAO in this example was not all converted.
Table 26: yield and quality of effluent produced from FCC unit F
Unit cell
FCC
Gasoline (C)5Yield-220 ℃ C.)
By weight%
42.0
Gas oil (220-360 ℃) yield
By weight%
14.2
Yield of vacuum distillate (360 ℃ -540 ℃)
By weight%
13.8
Yield of vacuum residue (540 ℃ C. +)
By weight%
1.2
Quality of overall performance
Using HSV with a total of 0.089h-1And with a medium temperature (420/420 c) the conversion of the heavy 540 c + fraction before the deasphalting step according to the inventive solution was 86.1 wt%, i.e. 26.9 wt% higher than in example 7 at the same temperature level. Thus, the amount of unconverted VR recovered in example 4 was reduced to about 1/3. Furthermore, the unconverted VR of example 8 contains lower amounts of conradson carbon residue and C compared to example 77Asphaltenes, which can recover more DAO from unconverted VR (66.8 wt% recoverable in this example, and 54.1 wt% recoverable in example 7). This variant according to the invention is therefore accompanied by the production of only a minor amount of bitumen corresponding to 3.6% by weight with respect to the fresh starting material. In this example, the DAO fraction was converted in an FCC unit. With this successive scheme according to the invention, for 0.089h-1The total conversion of the heavy 540 c + fraction relative to the initial heavy 540 c + fraction in the overall scheme was 94.4 wt%, i.e., 14.4 percent higher conversion than in example 7, for the total Hourly Space Velocity (HSV) and medium temperature (420/420 c). Thus, a conversion in excess of 90% by weight with respect to the fresh feed can be obtained according to the solution of the invention.
As described in these 8 examples, a butane (C) removal process may be used in the deasphalting process4) Other solvents than pentane (C)5)). By C5The deasphalting of (a) can increase the yield of DAO and improve the advantages of the invention.
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