Method and system for producing chemical raw materials through crude oil hydrocracking

Abstract

The invention relates to a method and a system for producing chemical raw materials by hydrocracking crude oil, which are characterized in that the crude oil is firstly subjected to simple pre-fractionation, and then the obtained light oil fraction, middle-section oil fraction and optional heavy fraction are respectively treated, so that the investment and energy consumption caused by directly hydrotreating the crude oil are avoided; carrying out two-stage hydrotreatment on the obtained middle-stage oil fraction, and then carrying out fractionation treatment to obtain a gas-phase product, a light oil product and unconverted oil; the light oil fraction, the gas phase product and the light oil product obtained by pre-fractionation can be directly used as raw materials of a chemical device, so that the yield of the raw materials of the chemical device can be increased; optionally, the heavy oil fraction is mixed with the middle-section oil fraction after asphaltene, metal and other impurities are removed through the heavy oil hydrotreating unit, so that the quality of the raw materials of the chemical device can be ensured. Besides, by adopting the method disclosed by the invention, devices for atmospheric and vacuum distillation, hydrogenation pretreatment, catalytic reforming and the like in the conventional oil refining process can be omitted, the process flow can be simplified, and the device investment and energy consumption can be reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical industry, and in particular, to a method and system for producing chemical raw materials by hydrocracking of crude oil. Background Art

[0002] Generally, crude oil is the oil extracted from underground without being processed. Crude oil is a dark brown viscous oily liquid with a green fluorescence and a special smell. The main components of crude oil are carbon and hydrogen, as well as a small amount of sulfur, oxygen, nitrogen and trace amounts of phosphorus, arsenic, potassium, sodium, calcium, magnesium, nickel, iron, vanadium and other elements. The molecular weight of crude oil is 280-300, and the freezing point is -50-24°C. Crude oil can be divided into three categories according to its composition: paraffin-based crude oil, naphthenic crude oil and intermediate-based crude oil; according to the sulfur content, it can be divided into four categories: ultra-low sulfur crude oil, low sulfur crude oil, sulfur-containing crude oil and high sulfur crude oil; according to its specific gravity, it can be divided into three categories: light crude oil, medium crude oil and heavy crude oil.

[0003] In recent years, with the overcapacity of oil refining equipment, the demand for liquid fuel oil for transportation has peaked, and the proportion of oil used in chemical industry has increased year by year, the focus of oil refining enterprises has gradually shifted from ensuring the demand for refined oil to producing high-end chemical raw materials. Conventional crude oil processing procedures can also produce chemical materials, but they need to be processed through multiple sets of industrial equipment such as atmospheric and vacuum pressure reduction, hydrogenation pretreatment, catalytic cracking, hydrofining, hydrocracking, and catalytic reforming. The existing technology uses crude oil to produce chemical materials. The method requires that the crude oil undergo pre-hydrogenation reaction, hydrofining reaction, and hydrocracking reaction to obtain the reaction effluent, which enters the fractionation tower after gas-liquid separation to obtain chemical materials. Although conventional crude oil processing methods and existing technologies can use crude oil to produce chemical materials, there are problems such as long processing flow, high energy consumption of the equipment, and low yield of chemical raw materials. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method and system for producing chemical raw materials by hydrocracking of crude oil, so as to solve the problems of high energy consumption and low yield of chemical raw materials in the prior art.

[0005] In order to achieve the above-mentioned object, the first aspect of the present disclosure provides a method for producing chemical raw materials by hydrocracking of crude oil, the method comprising: subjecting the petroleum crude oil to a first fractionation treatment in a crude oil fractionation unit to obtain a light oil fraction, a middle oil fraction and an optional heavy oil fraction; subjecting the middle oil fraction to a first hydrocracking unit for a first hydroprocessing treatment to obtain a first hydrogenation product; subjecting the first hydrogenation product to a second fractionation treatment in a product fractionation unit to obtain a gas product, a light oil product and unconverted oil; subjecting the unconverted oil to a second hydrocracking unit for a second hydroprocessing treatment, and the obtained second hydroprocessing product is mixed with the first hydroprocessing product and then fed into the product fractionation unit;

[0006] Optionally, the heavy oil fraction is subjected to heavy oil hydrogenation treatment in a heavy oil hydrogenation unit, and the obtained heavy oil hydrogenation product is mixed with the mid-stage oil fraction.

[0007] Optionally, the operating conditions of the crude oil fractionation unit include: the cut point between the light oil fraction and the middle oil fraction is 160-200°C, preferably 170-185°C; the cut point between the middle oil fraction and the heavy oil fraction is 480-550°C, preferably 500-520°C.

[0008] Optionally, the operating conditions of the heavy oil hydrogenation unit include: inlet temperature of 250-420°C, hydrogen partial pressure of 12.0-16.0 MPa, volume space velocity of 0.2-1.0 h -1 , hydrogen oil volume ratio 400~1000Nm 3 / m 3 .

[0009] Optionally, the first-stage hydrocracking unit comprises a hydrofining reactor and a hydrocracking reactor arranged in series; the method further comprises subjecting the middle oil fraction to the first-stage hydrotreatment in sequence through the hydrofining reactor and the hydrocracking reactor.

[0010] Optionally, the operating conditions of the first stage hydrocracking unit include: a hydrogen partial pressure of 10.0 to 15.0 MPa, a hydrogen to oil volume ratio of 500 to 1000 Nm 3 / m 3 The inlet temperature of the hydrotreating reactor is 340-380°C, and the volume space velocity of the hydrotreating reactor is 1.0-2.0h -1 The volume space velocity of the hydrocracking reactor is 1.5 to 2.8 h -1 .

[0011] Optionally, the operating conditions of the two-stage hydrocracking unit include: inlet temperature of 340-380°C, hydrogen partial pressure of 10.0-15.0 MPa, volume space velocity of 1.5-2.8 h -1 , hydrogen to oil volume ratio is 500~1000Nm 3 / m 3 .

[0012] Optionally, the operating conditions of the product fractionation unit include: the cut point of the gas product and the light oil product is 40-80°C, preferably 50-65°C; the cut point of the light oil product and the unconverted oil is 160-200°C, preferably 170-185°C.

[0013] Optionally, the catalyst used in the first-stage hydrotreatment includes a hydrorefining catalyst and a first hydrocracking catalyst; the hydrorefining catalyst includes a carrier and an active metal component loaded on the carrier; the carrier includes aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W; the first hydrocracking catalyst includes a carrier and an active metal component loaded on the carrier, the carrier includes aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W.

[0014] Optionally, the catalyst used in the second-stage hydroprocessing includes a second hydrocracking catalyst; the second hydrocracking catalyst includes a carrier and an active metal component loaded on the carrier, the carrier includes aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W.

[0015] The second aspect of the present disclosure is a system for producing chemical materials by hydrocracking crude oil using the method described in the first aspect, the system comprising a crude oil fractionation unit, a first-stage hydrocracking unit, a product fractionation unit, a second-stage hydrocracking unit and an optional heavy oil hydrogenation unit; the crude oil fractionation unit comprises a petroleum crude oil inlet, a light oil fraction outlet, a middle oil fraction outlet and a heavy oil fraction outlet; the first-stage hydrocracking unit comprises a middle oil fraction inlet, a heavy oil hydrogenation product inlet and a first-stage hydrogenation product outlet; the product fractionation unit comprises a first-stage hydrogenation product inlet, a second-stage hydrogenation product inlet, a gas product outlet, a light oil product outlet and an unconverted oil outlet; the second-stage hydrocracking unit comprises The unconverted oil inlet and the second-stage hydrogenation product outlet; the heavy oil hydrogenation unit includes a heavy oil fraction inlet and a heavy oil hydrogenation product outlet; the petroleum crude oil inlet of the crude oil fractionation unit is connected to the petroleum crude oil source, and the middle oil fraction outlet of the crude oil fractionation unit is connected to the middle oil fraction inlet of the first-stage hydrocracking unit; the first-stage hydrogenation product outlet of the first-stage hydrocracking unit is connected to the first-stage hydrogenation product inlet of the product fractionation unit; the unconverted oil outlet of the product fractionation unit is connected to the unconverted oil inlet of the second-stage hydrocracking unit; the second-stage hydrogenation product outlet of the second-stage hydrocracking unit is connected to the second-stage hydrogenation product inlet of the product fractionation unit;

[0016] Optionally, the heavy oil fraction inlet of the heavy oil hydrogenation unit is connected to the heavy oil fraction outlet of the crude oil fractionation unit; the heavy oil hydrogenation product outlet of the heavy oil hydrogenation unit is connected to the heavy oil hydrogenation product inlet of the first-stage hydrocracking unit.

[0017] Through the above technical scheme, the crude oil is first subjected to simple pre-fractionation, and then the obtained light oil fraction, middle oil fraction and optional heavy fraction are treated separately, so as to avoid direct hydrogenation of the crude oil and cause investment and energy consumption; the obtained middle oil fraction is subjected to two-stage hydrogenation treatment and then fractionation treatment to obtain gas phase products, light oil products and unconverted oil; the light oil fraction, gas phase products and light oil products obtained by pre-fractionation can be directly used as raw materials for chemical plants, which can improve the yield of raw materials for chemical plants; the heavy oil fraction can be optionally mixed with the middle oil fraction after removing impurities such as asphaltene and metals through the heavy oil hydroprocessing unit, so as to ensure the quality of the obtained raw materials for chemical plants. In addition, the method disclosed in the present invention can save the devices such as atmospheric and vacuum distillation, hydrogenation pretreatment and catalytic reforming in the conventional oil refining process, simplify the process flow, and reduce device investment and energy consumption.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0020] Figure 1 The present invention discloses a flow chart of a method for producing chemical raw materials by hydrocracking of crude oil.

[0021] Figure 2 It is a flow chart of the method for producing chemical raw materials by hydrocracking of crude oil in Example 2 of the present disclosure.

[0022] Description of Reference Numerals

[0023] 1. Crude oil fractionation unit; 2. First-stage hydrocracking unit; 3. Heavy oil hydrogenation unit; 4. Product fractionation unit; 5. Second-stage hydrocracking unit; 11. Petroleum crude oil; 12. Light oil fraction; 13. Middle oil fraction; 14. Heavy oil fraction; 15. Heavy oil hydrogenation product; 16. First-stage hydrogenation product; 17. Gas product; 18. Light oil product; 19. Unconverted oil; 20. Second-stage hydrogenation product; 21. Middle and heavy oil fractions. DETAILED DESCRIPTION

[0024] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0025] In the present disclosure, the terms "first, second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first, second" may explicitly or implicitly include one or more of the feature. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] The first aspect of the present disclosure provides a method for producing chemical raw materials by hydrocracking of crude oil, the method comprising: subjecting petroleum crude oil 11 to a first fractionation treatment in a crude oil fractionation unit 1 to obtain a light oil fraction 12, a middle oil fraction 13 and an optional heavy oil fraction 14; subjecting the middle oil fraction 13 to a first hydrocracking unit 2 for a first hydroprocessing to obtain a first hydrogenation product 16; subjecting the first hydrogenation product 16 to a second fractionation treatment in a product fractionation unit 4 to obtain a gas product 17, a light oil product 18 and an unconverted oil 19; subjecting the unconverted oil 19 to a second hydrocracking unit 5 for a second hydroprocessing, and mixing the obtained second hydroprocessing product 20 with the first hydroprocessing product 16 and then subjecting the mixed products to the product fractionation unit 4; optionally, subjecting the heavy oil fraction 14 to a heavy oil hydroprocessing unit 3 to a heavy oil hydroprocessing, and mixing the obtained heavy oil hydroprocessing product 15 with the middle oil fraction 13.

[0027] Through the above technical scheme, the crude oil 11 is first pre-fractionated, and then the obtained light oil fraction 12, the middle oil fraction 13 and the optional heavy oil fraction 14 are treated separately, so as to avoid directly hydrogenating the crude oil 11 and causing investment and energy consumption; the obtained middle oil fraction 13 is subjected to two-stage hydrogenation treatment and then fractionated to obtain gas products 17, light oil products 18 and unconverted oil 19; the light oil fraction 12, gas phase products and light oil products 18 obtained by pre-fractionation can be directly used as raw materials for chemical plants, which can improve the yield of raw materials for chemical plants; the heavy oil fraction 14 can be optionally mixed with the middle oil fraction 13 after removing impurities such as asphaltene and metals through the heavy oil hydroprocessing unit, so as to ensure the quality of the obtained raw materials for chemical plants. In addition, the method disclosed in the present invention can save the devices such as atmospheric and vacuum distillation, hydrogenation pretreatment and catalytic reforming in the conventional oil refining process, simplify the process flow, and reduce device investment and energy consumption.

[0028] The petroleum crude oil 11 used in the present disclosure is a crude oil or a mixture of multiple crude oils, wherein the crude oil is conventionally selected in the art, and the present application does not impose any restrictions on the source of the crude oil. In a preferred embodiment, the API gravity of the petroleum crude oil 11 is ≮20, the asphaltene content is ≯6000 μg / g, and the metal content is ≯150 μg / g. The metals in the crude oil include metal elements such as Fe, Ca, Ni and V.

[0029] In one embodiment, the method further includes, before the first fractionation treatment, pre-treating the crude oil 11, the pre-treating including dehydration and desalination. Dehydration and desalination are both conventional choices in the art, and the present application does not make special requirements for the processes of dehydration and desalination. For example, desalination can be performed using an electric desalination system to remove inorganic salts in the crude oil 11, so as to prevent the inorganic salts from affecting the quality of the product during the subsequent treatment process.

[0030] In one embodiment, the petroleum crude oil 11 after dehydration and / or desalting is preliminarily fractionated in the crude oil fractionation unit 1 to separate the easily separable light oil fraction 12, middle oil fraction 13 and heavy oil fraction 14 in the petroleum crude oil 11, and then the light oil fraction 12, middle oil fraction 13 and heavy oil fraction 14 are processed separately. On the one hand, it can solve the problem of increased energy consumption and investment caused by directly processing the petroleum crude oil 11; on the other hand, it can reduce the pressure of subsequent processing units to process a large amount of materials; on the other hand, targeted processing of different materials can improve the corresponding processing effect, thereby ensuring the quality of the raw materials of the chemical plant while further improving the yield of the target product.

[0031] The crude oil fractionation unit 1 may be a normal pressure tower or a vacuum tower, preferably a normal pressure tower.

[0032] Among them, in order to take into account both energy saving and separation effect, the operating conditions of the crude oil fractionation unit 1 are limited. Specifically, the operating conditions of the crude oil fractionation unit 1 include: the distillation cut point between the light oil fraction 12 and the middle oil fraction 13 is 160-200°C, preferably 170-185°C; the distillation cut point between the middle oil fraction 13 and the heavy oil fraction 14 is 480-550°C, preferably 500-520°C.

[0033] In one embodiment, the easily separated light oil fraction 12 in the crude oil 11 mainly includes naphtha components such as C5 / C6, so the light oil fraction 12 can be directly used as a raw material for a chemical plant and discharged from the system.

[0034] In one embodiment, the heavy oil fraction 14 mainly includes components such as heavy oil fraction with a distillation range of ≮480°C, asphaltene, and metals. The present disclosure allows the heavy oil fraction 14 and hydrogen to enter the heavy oil hydrogenation unit 3 to contact with the heavy oil hydrogenation catalyst for heavy oil hydrogenation treatment, and a heavy oil hydrogenation product 15 can be obtained. In this embodiment, the heavy oil fraction 14 can be hydrogenated to remove asphaltene and metal impurities, and the quality of the raw materials of the chemical plant can be further guaranteed.

[0035] Among them, the reactor of the heavy oil hydrogenation unit 3 is a conventional choice in the art, for example, the reactor can be one or more of a fixed bed reactor, an ebullating bed reactor and a suspended bed reactor; preferably, the reactor of the heavy oil hydrogenation unit 3 is a fixed bed reactor, multiple reactors are connected in series, and a mixed hydrogen inlet is provided between two adjacent reactors.

[0036] The heavy oil hydrogenation catalyst comprises a carrier and an active metal component supported on the carrier; the carrier comprises alumina and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W. The content of the active metal component is 1 to 10% by weight based on the total weight of the heavy oil hydrogenation catalyst.

[0037] The operating conditions of the heavy oil hydrogenation unit 3 include: inlet temperature of 250-420°C, preferably 360-420°C; hydrogen partial pressure of 12.0-16.0 MPa, preferably 13-16 MPa; volume space velocity of 0.2-1.0 h -1 , preferably 0.2 to 0.8h -1 ; Hydrogen oil volume ratio 400~1000Nm 3 / m 3 , preferably 600~1000Nm 3 / m 3 .

[0038] In one embodiment, the first stage hydrocracking unit 2 includes a hydrofining reactor and a hydrocracking reactor arranged in series.

[0039] Wherein, the hydrotreating reactor and the hydrocracking reactor are both fixed bed reactors, the hydrotreating reactor comprises 1 to 4 catalyst beds, the hydrocracking reactor comprises 2 to 7 catalyst beds, and a mixed hydrogen inlet is provided between two adjacent catalyst beds.

[0040] The method further comprises: allowing the middle oil fraction 13 and hydrogen to first enter a hydrotreating reactor to contact a hydrotreating catalyst for hydrotreating treatment to obtain a hydrotreating product; allowing the hydrotreating product and hydrogen to enter a hydrocracking reactor to contact a first hydrocracking catalyst for the first stage hydrogenation treatment to obtain the first stage hydrogenation product 16.

[0041] The middle oil fraction 13 mainly includes components such as diesel and wax oil.

[0042] The catalyst used in the first stage hydroprocessing includes a hydrorefining catalyst and a first hydrocracking catalyst.

[0043] The hydrorefining catalyst comprises a carrier and an active metal component loaded on the carrier; the carrier comprises aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W; based on the total weight of the hydrorefining catalyst, the content of the active metal component is 5 to 40 weight %.

[0044] Wherein, the first hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier, wherein the carrier comprises aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W; based on the total weight of the first hydrocracking catalyst, the content of the active metal component is 5 to 40 weight %.

[0045] The operating conditions of the first stage hydrocracking unit 2 include: hydrogen partial pressure of 10.0-15.0 MPa, preferably 12-15 MPa; hydrogen-to-oil volume ratio of 500-1000 Nm 3 / m 3 , preferably 600~900Nm 3 / m 3 The inlet temperature of the hydrotreating reactor is 340-380°C, preferably 345-365°C; the volume space velocity of the hydrotreating reactor is 1.0-2.0h -1 , preferably 1.2 to 1.7 hours -1 The volume space velocity of the hydrocracking reactor is 1.5 to 2.8 h -1 , preferably 1.6 to 2.4 hours -1 .

[0046] In one embodiment, the device of the product fractionation unit 4 can be an atmospheric pressure tower or a vacuum tower, preferably an atmospheric pressure tower.

[0047] Among them, in order to take into account both energy saving and separation effect, the operating conditions of the product fractionation unit 4 are limited. The specific operating conditions of the product fractionation unit 4 include: the distillation cut point of the gas product 17 and the light oil product 18 is 40-80°C, preferably 50-65°C; the distillation cut point of the light oil product 18 and the unconverted oil 19 is 160-200°C, preferably 170-185°C.

[0048] In one embodiment, the unconverted oil 19 and hydrogen enter the second-stage hydrocracking unit 5 to contact with the second hydrocracking catalyst for a second fractionation treatment to obtain a second-stage hydrogenation product 20; the second-stage hydrogenation product 20 is mixed with the first-stage hydrogenation product 16 and returned to the product fractionation unit 4.

[0049] The operating conditions of the second-stage hydrocracking unit 5 include: inlet temperature of 340-380°C, preferably 340-365°C; hydrogen partial pressure of 10.0-15.0 MPa, preferably 12-15 MPa; volume space velocity of 1.5-2.8 h -1 , preferably 1.8 to 2.6 hours -1 ; Hydrogen oil volume ratio is 500~1000Nm 3 / m 3 , preferably 600~1000Nm 3 / m 3 .

[0050] The catalyst used in the second-stage hydroprocessing comprises a second hydrocracking catalyst; the second hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier, the carrier comprises aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W; based on the total weight of the second hydrocracking catalyst, the content of the active metal component is 5 to 40 weight percent.

[0051] In one embodiment, when the crude oil is light crude oil or the metal and asphaltene content in the crude oil is low, the heavy oil hydroprocessing unit can be eliminated, and the petroleum crude oil 11 is separated by the crude oil fractionation unit 1 to obtain a light oil fraction 12 and a middle and heavy oil fraction 21, and the middle and heavy oil fractions 21 all enter the first-stage hydrocracking unit 2.

[0052] In one embodiment, a light hydrocarbon recovery, naphtha stabilization, and normal isobutane separation system can be set up according to demand, and the gas product 17 in the entire system can be concentratedly separated and recovered to produce high-quality liquefied gas products and stabilized naphtha. Furthermore, the liquefied gas can be separated into propane, normal butane, and isobutane components according to demand.

[0053] In one embodiment, if Figure 1 As shown, the method for producing chemical raw materials by hydrocracking of crude oil includes:

[0054] The petroleum crude oil 11 is subjected to a first fractionation treatment by a crude oil fractionation unit 1 to obtain a light oil fraction 12, a middle oil fraction 13 and a heavy oil fraction 14; the operating conditions of the crude oil fractionation unit 1 include: the fraction cut point between the light oil fraction 12 and the middle oil fraction 13 is 160-200° C.; the fraction cut point between the middle oil fraction 13 and the heavy oil fraction 14 is 480-550° C.;

[0055] The middle oil fraction 13 and hydrogen are firstly introduced into a hydrotreating reactor to contact with a hydrotreating catalyst for hydrotreating treatment to obtain a hydrotreating product; the hydrotreating product and hydrogen are introduced into a hydrocracking reactor to carry out the first stage hydrotreating with a first hydrocracking catalyst to obtain the first stage hydrogenation product 16; the operating conditions of the first stage hydrocracking unit 2 include: a hydrogen partial pressure of 10.0 to 15.0 MPa, a hydrogen to oil volume ratio of 500 to 1000 Nm 3 / m 3 The inlet temperature of the hydrotreating reactor is 340-380°C, and the volume space velocity of the hydrotreating reactor is 1.0-2.0h -1 The volume space velocity of the hydrocracking reactor is 1.5 to 2.8 h -1 ;

[0056] The first stage hydrogenation product 16 is subjected to a second fractionation treatment in a product fractionation unit 4 to obtain a gas product 17, a light oil product 18 and an unconverted oil 19; the operating conditions of the product fractionation unit 4 include: the fraction cut point of the gas product 17 and the light oil product 18 is 40-80° C.; the fraction cut point of the light oil product 18 and the unconverted oil 19 is 160-200° C.;

[0057] The unconverted oil 19 and hydrogen are contacted with the second hydrocracking catalyst through the second hydrocracking unit 5 for second-stage hydrogenation treatment, and the obtained second-stage hydrogenation product 20 is mixed with the first-stage hydrogenation product 16 and then enters the product fractionation unit 4; the operating conditions of the second-stage hydrocracking unit 5 include: inlet temperature of 340-380°C, hydrogen partial pressure of 10.0-15.0MPa, volume space velocity of 1.5-2.8h -1 , hydrogen to oil volume ratio is 500~1000Nm 3 / m 3 ;

[0058] The heavy oil fraction 14 and hydrogen enter the heavy oil hydrogenation unit 3 to contact with the heavy oil hydrogenation catalyst for heavy oil hydrogenation treatment, and the obtained heavy oil hydrogenation product 15 is mixed with the middle oil fraction 13; the operating conditions of the heavy oil hydrogenation unit 3 include: inlet temperature of 250-420°C, hydrogen partial pressure of 12.0-16.0MPa, volume space velocity of 0.2-1.0h -1 , hydrogen oil volume ratio 400~1000Nm 3 / m 3 .

[0059] In a second aspect of the present disclosure, a system for producing chemical materials by hydrocracking crude oil using the method described in the first aspect is provided, the system comprising a crude oil fractionation unit 1, a first-stage hydrocracking unit 2, a product fractionation unit 4, a second-stage hydrocracking unit 5 and an optional heavy oil hydrogenation unit 3; the crude oil fractionation unit 1 comprises a petroleum crude oil inlet, a light oil fraction outlet, a middle oil fraction outlet and a heavy oil fraction outlet; the first-stage hydrocracking unit 2 comprises a middle oil fraction inlet, a heavy oil hydrogenation product inlet and a first-stage hydrogenation product outlet; the product fractionation unit 4 comprises a first-stage hydrogenation product inlet, a second-stage hydrogenation product inlet, a gas product outlet, a light oil product outlet and an unconverted oil outlet; the second-stage hydrocracking unit 5 comprises an unconverted oil inlet and a second-stage hydrogenation product outlet; the heavy oil hydrogenation unit 3 comprises a heavy oil fraction inlet and a heavy oil hydrogenation product outlet; the petroleum crude oil inlet of the crude oil fractionation unit 1 is connected to a petroleum crude oil source so that the crude oil inlet is connected to the ... The crude oil 11 enters the crude oil fractionation unit 1 for the first fractionation treatment; the middle oil fraction outlet of the crude oil fractionation unit 1 is connected with the middle oil fraction inlet of the first hydrocracking unit 2, so that the middle oil fraction can enter the first hydrocracking unit 2 for the first hydrocracking treatment; the first hydrogenation product outlet of the first hydrocracking unit 2 is connected with the first hydrogenation product inlet of the product fractionation unit 4, so that the first hydrogenation product 16 can enter the product fractionation unit 4 for the second fractionation treatment; the unconverted oil outlet of the product fractionation unit 4 is connected with the unconverted oil inlet of the second hydrocracking unit 5, so that the unconverted oil 19 can enter the second hydrocracking unit 5 for the second hydrogenation treatment; the second hydrogenation product outlet of the second hydrocracking unit 5 is connected with the second hydrogenation product inlet of the product fractionation unit 4, so that the second hydrogenation product 20 can return to the product fractionation unit 4 for continued fractionation;

[0060] Optionally, the heavy oil fraction inlet of the heavy oil hydrogenation unit 3 is connected to the heavy oil fraction outlet of the crude oil fractionation unit 1, so that the heavy oil fraction 14 can enter the heavy oil hydrogenation unit 3 for heavy oil hydrogenation treatment; the heavy oil hydrogenation product outlet of the heavy oil hydrogenation unit 3 is connected to the heavy oil hydrogenation product inlet of the first-stage hydrocracking unit 2, so that the heavy oil hydrogenation product 15 can enter the first-stage hydrocracking unit 2 to participate in the first-stage hydrotreatment.

[0061] The present disclosure is further described in detail by way of examples. The raw materials used in the examples can be obtained through commercial sources. The properties of the petroleum crude oil used in the following examples and comparative examples are shown in Table 1, wherein the composition and content of the heavy oil hydrogenation catalyst, the hydrorefining catalyst, the first hydrocracking catalyst and the second hydrocracking catalyst are shown in Table 2.

[0062] Table 1 Properties of crude oil

[0063]

[0064]

[0065] Table 2 Composition and content of catalyst

[0066]

[0067] Example 1

[0068] Crude oil hydrocracking system to produce chemical raw materials Figure 1 As shown, the method for producing chemical raw materials by hydrocracking of crude oil includes:

[0069] A petroleum crude oil 11 (crude oil A) is subjected to a first fractionation treatment by a crude oil fractionation unit 1 to obtain a light oil fraction 12, a middle oil fraction 13 and a heavy oil fraction 14; the operating conditions of the crude oil fractionation unit 1 include: a fraction cut point between the light oil fraction 12 and the middle oil fraction 13 is 175° C.; a fraction cut point between the middle oil fraction 13 and the heavy oil fraction 14 is 520° C.;

[0070] The middle oil fraction 13 and hydrogen are firstly introduced into a hydrotreating reactor to contact with a hydrotreating catalyst for hydrotreating treatment to obtain a hydrotreating product; the hydrotreating product and hydrogen are introduced into a hydrocracking reactor to contact with a first hydrocracking catalyst for the first stage hydrotreating to obtain the first stage hydrogenation product 16; the operating conditions of the first stage hydrocracking unit 2 include: a hydrogen partial pressure of 15 MPa, a hydrogen-to-oil volume ratio of 750 Nm 3 / m 3 The inlet temperature of the hydrotreating reactor is 355°C, and the volume space velocity of the hydrotreating reactor is 1.3h -1 The volume space velocity of the hydrocracking reactor is 1.8h -1 ;

[0071] The first stage hydrogenation product 16 is subjected to a second fractionation treatment in a product fractionation unit 4 to obtain a gas product 17, a light oil product 18 and an unconverted oil 19; the operating conditions of the product fractionation unit 4 include: the fraction cut point of the gas product 17 and the light oil product 18 is 50° C.; the fraction cut point of the light oil product 18 and the unconverted oil 19 is 175° C.;

[0072] The unconverted oil 19 and hydrogen are contacted with the second hydrocracking catalyst through the second hydrocracking unit 5 for second-stage hydrogenation treatment, and the obtained second-stage hydrogenation product 20 is mixed with the first-stage hydrogenation product 16 and then enters the product fractionation unit 4; the operating conditions of the second-stage hydrocracking unit 5 include: inlet temperature of 358°C, hydrogen partial pressure of 14MPa, volume space velocity of 2.0h -1 , hydrogen to oil volume ratio is 800Nm 3 / m3 ;

[0073] The heavy oil fraction 14 and hydrogen enter the heavy oil hydrogenation unit 3 to contact the heavy oil hydrogenation catalyst for heavy oil hydrogenation treatment, and the obtained heavy oil hydrogenation product 15 is mixed with the middle oil fraction 13; the operating conditions of the heavy oil hydrogenation unit 3 include: inlet temperature of 362°C, hydrogen partial pressure of 15.5MPa, volume space velocity of 1.3h -1 , hydrogen oil volume ratio 800Nm 3 / m 3 .

[0074] The properties of the products are shown in Table 3.

[0075] Example 2

[0076] Crude oil hydrocracking system to produce chemical raw materials Figure 2 As shown;

[0077] The method for producing chemical raw materials by crude oil hydrocracking is the same as that in Example 1, except that the petroleum crude oil 11 (crude oil B) is subjected to a first fractionation treatment in a crude oil fractionation unit 1 to obtain a light oil fraction 12 and a middle and heavy oil fraction 21; the middle and heavy oil fraction 21 are all fed into a first hydrocracking unit 2, wherein the fraction cut points of the light oil fraction 12 and the middle and heavy oil fraction 21 are 175°C.

[0078] Comparative Example 1

[0079] The petroleum crude oil in Example 1 was mixed with hydrogen and then passed through a pretreatment reaction zone, a hydrotreating reaction zone and a hydrocracking reaction zone in sequence, and was contacted with a hydrogenation protective agent, a hydrodemetallization agent, a hydrotreating catalyst, a hydrocracking catalyst and a post-hydrotreating catalyst in sequence for reaction. The properties of the obtained product are shown in Table 3.

[0080] Comparative Example 2

[0081] Crude oil B was used as the petroleum crude oil and was processed by the method in Comparative Example 1. The properties obtained are shown in Table 3.

[0082] Table 3 Products of Examples and Comparative Examples

[0083]

[0084] As shown in Table 3, by comparing the data of Examples 1 to 2 and Comparative Examples 1 to 2, it can be seen that the method of the present invention is used to separate crude oil into different fractions and enter the most suitable hydrogenation reaction zone, which can ensure the quality of the raw materials of the chemical plant while improving the yield of the raw materials of the chemical plant; in addition, the method of the present invention can reduce the energy consumption and investment of the plant.

[0085] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0086] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0087] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for producing chemical raw materials by hydrocracking of crude oil, characterized in that: The method includes: The petroleum crude oil is subjected to a first fractionation treatment in a crude oil fractionation unit (1) to obtain a light oil fraction, a middle oil fraction and an optional heavy oil fraction; The middle oil fraction is fed into a first-stage hydrocracking unit (2) for first-stage hydrogenation treatment to obtain a first-stage hydrogenation product; The first stage hydrogenation product is subjected to a second fractionation treatment in a product fractionation unit (4) to obtain a gas product, a light oil product and unconverted oil; The unconverted oil is subjected to a second-stage hydrogenation treatment in a second-stage hydrocracking unit (5), and the obtained second-stage hydrogenation product is mixed with the first-stage hydrogenation product and then enters the product fractionation unit (4); Optionally, the heavy oil fraction is subjected to heavy oil hydrogenation treatment in a heavy oil hydrogenation unit (3), and the obtained heavy oil hydrogenation product is mixed with the mid-stage oil fraction.

2. The method according to claim 1, characterized in that The operating conditions of the crude oil fractionation unit (1) include: the cut point between the light oil fraction and the middle oil fraction is 160-200°C, preferably 170-185°C; the cut point between the middle oil fraction and the heavy oil fraction is 480-550°C, preferably 500-520°C.

3. The method according to claim 1, characterized in that The operating conditions of the heavy oil hydrogenation unit (3) include: an inlet temperature of 250-420°C, a hydrogen partial pressure of 12.0-16.0 MPa, a volume space velocity of 0.2-1.0 h -1 , hydrogen oil volume ratio 400~1000Nm 3 / m 3 .

4. The method according to claim 1, characterized in that: The first stage hydrocracking unit (2) comprises a hydrofining reactor and a hydrocracking reactor which are arranged in series; The method further comprises subjecting the middle oil fraction to the first stage of hydrogenation treatment in a hydrofining reactor and a hydrocracking reactor in sequence.

5. The method according to claim 4, characterized in that The operating conditions of the first stage hydrocracking unit (2) include: a hydrogen partial pressure of 10.0 to 15.0 MPa, a hydrogen to oil volume ratio of 500 to 1000 Nm 3 / m 3 The inlet temperature of the hydrotreating reactor is 340-380°C, and the volume space velocity of the hydrotreating reactor is 1.0-2.0h -1 The volume space velocity of the hydrocracking reactor is 1.5 to 2.8 h -1 .

6. The method according to claim 1, characterized in that The operating conditions of the two-stage hydrocracking unit (5) include: an inlet temperature of 340-380°C, a hydrogen partial pressure of 10.0-15.0 MPa, and a volume space velocity of 1.5-2.8 h -1 , hydrogen to oil volume ratio is 500~1000Nm 3 / m 3 .

7. The method according to claim 1, characterized in that The operating conditions of the product fractionation unit (4) include: the cut point of the gas product and the light oil product is 40-80°C, preferably 50-65°C; the cut point of the light oil product and the unconverted oil is 160-200°C, preferably 170-185°C.

8. The method according to claim 1, characterized in that The catalyst used in the first stage hydroprocessing includes a hydrofining catalyst and a first hydrocracking catalyst; The hydrotreating catalyst comprises a carrier and an active metal component supported on the carrier; the carrier comprises aluminum oxide and / or silicon oxide, and the active metal component is selected from one or more of Ni, Co, Mo, and W; The first hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier. The carrier comprises aluminum oxide and / or silicon oxide. The active metal component is selected from one or more of Ni, Co, Mo, and W.

9. The method according to claim 1, characterized in that: The catalyst used in the second-stage hydroprocessing includes a second hydrocracking catalyst; The second hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier. The carrier comprises aluminum oxide and / or silicon oxide. The active metal component is selected from one or more of Ni, Co, Mo, and W.

10. A system for producing chemical materials by hydrocracking crude oil using the method according to any one of claims 1 to 9, characterized in that: The system comprises a crude oil fractionation unit (1), a first-stage hydrocracking unit (2), a product fractionation unit (4), a second-stage hydrocracking unit (5) and an optional heavy oil hydrogenation unit (3); The crude oil fractionation unit (1) comprises a petroleum crude oil inlet, a light oil fraction outlet, a middle oil fraction outlet and a heavy oil fraction outlet; The first stage hydrocracking unit (2) comprises a middle oil fraction inlet, a heavy oil hydrogenation product inlet and a first stage hydrogenation product outlet; The product fractionation unit (4) comprises a first stage hydrogenation product inlet, a second stage hydrogenation product inlet, a gas product outlet, a light oil product outlet and an unconverted oil outlet; The second-stage hydrocracking unit (5) comprises an unconverted oil inlet and a second-stage hydrogenation product outlet; The heavy oil hydrogenation unit (3) comprises a heavy oil fraction inlet and a heavy oil hydrogenation product outlet; The petroleum crude oil inlet of the crude oil fractionation unit (1) is connected to the petroleum crude oil source, the middle oil fraction outlet of the crude oil fractionation unit (1) is connected to the middle oil fraction inlet of the first hydrocracking unit (2); the first stage hydrogenation product outlet of the first stage hydrocracking unit (2) is connected to the first stage hydrogenation product inlet of the product fractionation unit (4); the unconverted oil outlet of the product fractionation unit (4) is connected to the unconverted oil inlet of the second stage hydrocracking unit (5); the second stage hydrogenation product outlet of the second stage hydrocracking unit (5) is connected to the second stage hydrogenation product inlet of the product fractionation unit (4); Optionally, the heavy oil fraction inlet of the heavy oil hydrogenation unit (3) is connected to the heavy oil fraction outlet of the crude oil fractionation unit (1); and the heavy oil hydrogenation product outlet of the heavy oil hydrogenation unit (3) is connected to the heavy oil hydrogenation product inlet of the first-stage hydrocracking unit (2).

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