A processing method for producing chemical raw materials from crude oil

Abstract

The present invention discloses a processing method for producing chemical raw materials from crude oil. The method includes: after the crude oil is desalted by electricity, it enters a flash tower to separate out the light naphtha fraction, and then enters an atmospheric tower to separate out the atmospheric tower top oil and atmospheric residue; the atmospheric residue enters a vacuum tower to separate out the vacuum tower top oil and vacuum residue; wherein, the initial boiling point of the atmospheric tower top oil is 50°C to 80°C, and the final boiling point is 300°C to 400°C; the initial boiling point of the vacuum tower top oil is 300 to 360°C, and the final boiling point is 460°C to 520°C; in the presence of hydrogen, the atmospheric tower top oil and the vacuum tower top oil are mixed and sequentially enter a first hydrocracking reaction zone and a second hydrocracking reaction zone for hydrocracking reactions; finally, gas fraction, light naphtha, heavy naphtha and tail oil are obtained through separation and fractionation. This method can greatly improve the quality and yield of chemical products.

Description

Technical Field

[0001] The present invention relates to a processing method for crude oil, and particularly to a processing method for efficiently separating paraffins and cyclic hydrocarbons in crude oil by hydrocracking to produce chemical raw materials. Background Art

[0002] With the continuous increase in the demand for petroleum products, conventional crude oil resources are becoming increasingly depleted, and the supply of crude oil is showing a trend of heavy and inferior quality. At the same time, with the continuous increase in the demand for various light oils, the demand for fuel oils, especially some medium and high sulfur fuel oils, in various countries is continuously decreasing. Therefore, the use of appropriate processing technologies to improve the processing capacity of heavy / low-quality crude oil has become the key for refineries to increase economic benefits in the refining process. With the development and maturity of the refining industry, the use of production technologies for high-quality chemical raw materials and technologies for producing more aromatics and light olefins can rationally utilize petroleum resources, thereby promoting the improvement of enterprise economic benefits. As a development trend of refining technology, the integrated refining-chemical petroleum refining technology can, through the conversion of heavy oil, increase the production of chemical raw materials such as ethylene, propylene, and aromatics, and provide high-quality chemical raw materials for chemical plants such as ethylene and aromatics.

[0003] CN201580070326.4 discloses a method for preparing LPG and BTX, comprising: a) subjecting a mixed hydrocarbon stream to a first hydrocracking in the presence of a first hydrocracking catalyst to prepare a first hydrocracking product stream; b) separating the first hydrocracking product stream to provide at least one light hydrocarbon stream comprising at least C2 and C3 hydrocarbons, an intermediate hydrocarbon stream composed of C4 and / or C5 hydrocarbons, and a heavy hydrocarbon stream comprising at least C6+ hydrocarbons, and c) subjecting the heavy hydrocarbon stream to a second hydrocracking in the presence of a second hydrocracking catalyst to prepare a second hydrocracking product stream comprising BTX, wherein the second hydrocracking is more severe than the first hydrocracking, d) wherein, in the presence of a C4 hydrocracking catalyst, at least a portion of the intermediate hydrocarbon stream is subjected to C4 hydrocracking to prepare a C4 hydrocracking product stream, and the C4 hydrocracking is optimized for converting C4 hydrocarbons into C3 hydrocarbons.

[0004] CN201480037272.7 discloses a method for producing light olefin hydrocarbon compounds from a hydrocarbon feedstock, comprising the following steps: (a) feeding the hydrocarbon feedstock to a reaction zone for ring opening; (b) separating the reaction product produced by the reaction zone into an overhead stream and a side stream; (c) feeding the side stream from (b) to a gasoline hydrocracker (GHC) unit; (d) separating the reaction product of the GHC in step (c) into an overhead stream comprising hydrogen, methane, ethane, and liquefied petroleum gas and a stream comprising aromatic hydrocarbon compounds and a small amount of hydrogen and non-aromatic hydrocarbon compounds; (e) feeding the overhead stream from the gasoline hydrocracker (GHC) unit to a steam cracker unit.

[0005] In summary, petroleum hydrocarbons have a complex composition, mainly including alkanes, cycloalkanes and aromatics. Among them, alkanes, especially small-molecule alkanes, are high-quality ethylene raw materials, while cycloalkanes and aromatics are high-quality reforming feeds. In the prior art, for the conversion of crude oil, it is impossible to achieve the mixed processing of different fractions, nor can it selectively enrich alkanes (including long side chains on cyclic hydrocarbons) efficiently into ethylene raw materials and enrich cyclic hydrocarbons into reforming raw materials. Therefore, in view of the above problems, it is of great significance to develop an excellent processing method for producing high-quality chemical raw materials. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a processing method for producing chemical raw materials from crude oil, which can significantly improve the quality and yield of chemical raw materials, especially the aromatic potential content of heavy naphtha.

[0007] The present invention provides a processing method for producing chemical raw materials from crude oil, and the method includes:

[0008] (1) After the crude oil is desalted by electro-de-salting, it enters a flash tower to separate the light naphtha fraction, and then enters an atmospheric tower to separate the overhead oil of the atmospheric tower and the atmospheric residue; the atmospheric residue enters a vacuum tower to separate the overhead oil of the vacuum tower and the vacuum residue; wherein, the initial boiling point of the overhead oil of the atmospheric tower is 50°C to 80°C, and the final boiling point is 300°C to 400°C; the initial boiling point of the overhead oil of the vacuum tower is 300 to 360°C, and the final boiling point is 460°C to 520°C;

[0009] (2) In the presence of hydrogen, the overhead oil of the atmospheric tower and the overhead oil of the vacuum tower obtained in step (1) are mixed and enter the first hydrocracking reaction zone to selectively crack the n-paraffins in the first hydrocracking product to obtain the first hydrocracking product; wherein, the mass content of C7 + n-paraffins in the first hydrocracking product is controlled at 0.1% to 5.0%;

[0010] (3) In the presence of hydrogen, the first hydrocracking product enters the second hydrocracking reaction zone to obtain a second hydrocracking product containing monocyclic cyclic hydrocarbons;

[0011] (4) The second hydrocracking product is separated and fractionated to obtain a gas fraction, light naphtha, heavy naphtha and tail oil.

[0012] According to the present invention, the properties of the crude oil in step (1) are as follows: the density is 0.80 g / cm 3 ~1.10 g / cm 3 , preferably 0.85 g / cm 3 ~0.95 g / cm 3; the nitrogen mass content is 0.1% to 0.6%, preferably 0.2% to 0.4%; the sulfur mass content is 1% to 6%, preferably 2% to 4%; the metal content is 10 mg / kg to 100 mg / kg, preferably 20 mg / kg to 60 mg / kg.

[0013] According to the present invention, in step (1), the initial boiling point of the overhead oil of the atmospheric column is 60°C to 70°C; the final boiling point is 320°C to 340°C.

[0014] According to the present invention, in step (1), the initial boiling point of the overhead oil of the vacuum column is 320 to 340°C; the final boiling point is 480°C to 500°C.

[0015] According to the present invention, in step (1), the atmospheric distillation conditions are as follows: the top pressure is 0.04 MPa to 0.12 MPa, preferably 0.06 MPa to 0.10 MPa; the atmospheric distillation feed temperature is 330°C to 390°C, preferably 350°C to 370°C.

[0016] According to the present invention, in step (1), the vacuum distillation conditions are as follows: the top pressure is 0.5 kPa to 5 kPa, preferably 1 kPa to 3 kPa; the vacuum distillation feed temperature is 350°C to 460°C, preferably 380°C to 420°C.

[0017] According to the present invention, in step (1), the mass content of aromatics with more than three rings in the overhead oil of the vacuum column is not higher than 1.0%, preferably 0.2% to 0.6%.

[0018] According to the present invention, the overhead oil of the atmospheric column and the overhead oil of the vacuum column may contain impurities such as sulfur and nitrogen. According to actual needs, a hydrofining catalyst may be provided upstream of the first hydrocracking catalyst to remove impurities such as sulfur and nitrogen. Among them, the nitrogen content in the reaction stream in contact with the first hydrocracking catalyst is preferably below 50 mg / kg, more preferably below 20 mg / kg.

[0019] According to the present invention, preferably, in step (2), the mass content of C7 + n-alkanes in the first hydrocracking product is controlled at 1.0% to 3.0%.

[0020] According to the present invention, the chemical raw materials mainly include ethane, propane, butane, light naphtha, and may also include heavy naphtha. Among them, heavy naphtha is used as a reforming raw material to produce BTX, and ethane, propane, butane, and light naphtha are used as raw materials for producing light olefins. For example, as steam cracking raw materials to produce ethylene, and propane and butane can also be directly dehydrogenated to produce propylene and butene. Among them, light olefins refer to olefins with four or fewer carbon atoms, especially ethylene, propylene, and butadiene.

[0021] According to the present invention, in step (2), the first hydrocracking reaction zone is filled with a first hydrocracking catalyst, and the first hydrocracking catalyst can be one or more catalysts. In step (3), the first hydrocracking catalyst comprises an active metal component and a support; the support comprises a molecular sieve having a selective cracking of normal paraffins, preferably selected from one or more of ZSM-5 molecular sieve, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 and ZSM-38 molecular sieves, and more preferably ZSM-5 molecular sieve. The SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 20 to 60. The support may further comprise a binder. Preferably, the binder is alumina. The active metal component comprises at least one of metals of Group VIB and Group VIII, the metal of Group VIB is preferably molybdenum and / or tungsten, and the metal of Group VIII is preferably cobalt and / or nickel.

[0022] According to the present invention, in step (2), preferably, in the first hydrocracking catalyst, based on the weight of the catalyst, the content of the metal of Group VIB (calculated as the oxide) is 5.0% to 15.0%, the content of the metal of Group VIII (calculated as the oxide) is 2.0% to 5.0%, and the content of the support is 80.0% to 93.0%.

[0023] According to the present invention, in step (2), preferably, in the support of the first hydrocracking catalyst, based on the weight of the support, the content of the binder is 8% to 60%, and the content of the molecular sieve is 40% to 92%.

[0024] According to the present invention, in step (2), the specific surface area of the first hydrocracking catalyst is 200 to 400 m 2 / g, and the pore volume is 0.25 to 0.45 cm 3 / g. The particle size of the second hydrocracking catalyst is 1.0 to 3.0 μm.

[0025] According to the present invention, in step (2), the preparation method of the first hydrocracking catalyst can be prepared according to the conventional methods in the art. The preparation method includes the preparation of the support and the loading of the active metal component, and the preparation process of the support is as follows: the shape-selective cracking molecular sieve and the binder are mechanically mixed, formed, and then dried and calcined to make the catalyst support. The drying and calcination of the support can adopt conventional conditions. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcination are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0026] According to the present invention, in step (2), in the preparation method of the first hydrocracking catalyst, the method for loading the active metal component is a conventional method, such as kneading method, impregnation method, etc., and the impregnation method is preferably used. The impregnation method can be saturated impregnation method, excess impregnation method or complex impregnation method, that is, the catalyst carrier is impregnated with a solution containing the required active component, and then dried and calcined to obtain the second hydrocracking catalyst. The conditions for the drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for the calcination are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0027] According to the present invention, in step (2), the reaction conditions in the first hydrocracking reaction zone are as follows: the reaction pressure is 10 to 16 MPa, preferably 12 to 14 MPa.

[0028] According to the present invention, in step (2), the reaction conditions for the first hydrocracking reaction are as follows: the average reaction temperature is 250 to 450°C, preferably 300 to 400°C; the liquid hourly space velocity is 0.1 to 15.0 h -1 , preferably 1.0 to 5.0 h -1 ; the hydrogen-oil volume ratio is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0029] According to the present invention, in step (3), the second hydrocracking reaction zone is filled with the second hydrocracking catalyst. The second hydrocracking catalyst can be one or more catalysts. According to the present invention, in the second hydrocracking product of step (3), the mass ratio of the C6-C8 monocyclic cyclic hydrocarbons to the total cyclic hydrocarbons in the raw materials of the atmospheric tower top oil and the vacuum tower top oil is 0.20 to 0.40, preferably 0.29 to 0.35.

[0030] According to the present invention, the second hydrocracking catalyst in step (3) has the functions of ring-opening cracking of polycyclic cyclic hydrocarbons, selectively cracking isoparaffins or side chains of cyclic hydrocarbons and retaining monocyclic cyclic hydrocarbons. The second hydrocracking catalyst includes a cracking component, a hydrogenation component and a binder. The second hydrocracking catalyst can be a commercially available product or prepared according to the prior art. The hydrogenation component is at least one of a metal, a metal oxide, and a metal sulfide of an active metal component; the active metal component includes metals of Group VIB and / or Group VIII; the active metal component is more preferably at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel. In the second hydrocracking catalyst, the binder is alumina and / or silica; the cracking component includes an acidic molecular sieve, preferably at least one of Beta molecular sieve and Y molecular sieve.

[0031] According to the present invention, preferably, in step (3), the second hydrocracking reaction zone is filled with a catalyst with Y zeolite as the cracking component and a catalyst with Beta zeolite as the cracking component in sequence along the material flow direction; preferably, the volume ratio of the catalyst with Y zeolite as the cracking component to the catalyst with Beta zeolite as the cracking component is 5:1 to 1:2, preferably 3:1 to 1:1.

[0032] According to the present invention, for the second hydrocracking catalyst in step (3), based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component in terms of oxide is 5 wt% to 40 wt%, preferably 10 wt% to 30 wt%; the content of the cracking component is 10 wt% to 80 wt%, preferably 20 wt% to 60 wt%; the content of the binder is 5 wt% to 85 wt%, preferably 10 wt% to 50 wt%.

[0033] According to the present invention, in step (3), the preparation method of the second hydrocracking catalyst can be prepared according to the conventional methods in the art. The preparation method includes the preparation of the carrier and the loading of the hydrogenation component. The process of preparing the carrier is as follows: mechanically mix the cracking component and the binder, form, and then dry and calcine to make the catalyst carrier. The drying and calcining of the carrier can adopt conventional conditions. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcining are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0034] According to the present invention, in step (3), in the preparation method of the second hydrocracking catalyst, the method for loading the hydrogenation component is a conventional method, such as the kneading method, the impregnation method, etc., preferably the impregnation method. The impregnation method can be the saturated impregnation method, the excess impregnation method or the complex impregnation method, that is, impregnate the catalyst carrier with a solution containing the required hydrogenation component, and then dry and calcine to obtain the second hydrocracking catalyst. The conditions for drying are: drying at 100°C to 150°C for 1 to 12 hours. The conditions for calcining are: calcining at 450°C to 550°C for 2.5 to 6.0 hours.

[0035] According to the present invention, in step (3), the reaction conditions in the hydrocracking reaction zone are as follows: the reaction pressure is 10 to 16 MPa, preferably 12 to 14 MPa.

[0036] According to the present invention, in step (3), the reaction conditions in the hydrocracking reaction zone are as follows: the average reaction temperature is 250 to 450°C, preferably 300 to 400°C; the liquid hourly space velocity is 0.1 to 15.0 h -1 , preferably 1.0 to 5.0 h -1 ; the hydrogen-oil volume ratio is 100:1 to 2500:1, preferably 400:1 to 2000:1.

[0037] According to the present invention, preferably, the first hydrocracking reaction zone and the second hydrocracking reaction zone adopt the same pressure.

[0038] According to the present invention, preferably, in step (3), the effluent from the second hydrocracking reaction is subjected to supplementary hydrofining. The supplementary hydrofining can be carried out by loading a hydrofining catalyst at the bottom of the second hydrocracking reaction zone, or it can enter a separate hydrofining reaction zone.

[0039] According to the present invention, preferably, in step (3), the effluent from the second hydrocracking reaction can also first enter a fractionation system, and the heavy naphtha component separated is subjected to supplementary hydrofining.

[0040] According to the present invention, the tail oil obtained in step (4) is recycled to the second hydrocracking reaction zone.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects:

[0042] (1) In the prior art, when wax oil is used as a raw material for hydrocracking to produce chemical raw materials, the components above diesel oil are separated by the atmospheric and vacuum distillation towers and enter the vacuum tower. The final boiling point of the vacuum gas oil separated is generally 520 - 560 °C, resulting in a relatively high content of aromatics with more than three rings in the wax oil fraction. A relatively high reaction pressure is required to achieve the hydrocracking of three-ring aromatics, and a relatively high reaction pressure will also cause the ring opening and cracking of some single-ring aromatics during the hydrocracking process, resulting in the loss of aromatics. In the processing method of the present invention for producing chemical raw materials from crude oil, after the crude oil enters the atmospheric and vacuum distillation towers, it only undergoes simple topping treatment and then enters the vacuum tower. By controlling the content of aromatics with more than three rings in the overhead oil of the vacuum tower to be no higher than 1%, and selecting an appropriate reaction pressure, the mixed processing of aromatics with less than three rings is realized, reducing the loss of aromatics during the hydrogenation process and increasing the content of aromatics in the hydrogenation product. The overhead oil of the atmospheric tower and the overhead oil of the vacuum tower enter the first hydrocracking reaction zone with hydrogen. Mainly, the n-alkanes in the raw material and the long straight chains of isoparaffins and naphthenes containing long straight chains are selectively cracked to form small molecule n-alkanes, so that the content of C7 n-alkanes in the n-alkane conversion reaction effluent is 0.1% - 5.0%. The n-alkane conversion reaction effluent enters the second hydrocracking reaction zone, mainly to crack the polycyclic ring hydrocarbons and retain the monocyclic ring hydrocarbons and further break the side chains in each hydrocarbon to form small molecule hydrocarbons. In this way, a large amount of the straight-chain alkanes in the raw material can be converted into gas and light naphtha components, that is, enriched in ethylene raw materials, while the monocyclic ring hydrocarbons are retained in the heavy naphtha fraction, that is, enriched in reforming raw materials. Through simple fractionation, the efficient separation of paraffins and cyclic hydrocarbons can be achieved, increasing the production of high-quality ethylene cracking feedstock while improving the quality of heavy naphtha as catalytic reforming feedstock. + The content of n-alkanes is 0.1% - 5.0%. The n-alkane conversion reaction effluent enters the second hydrocracking reaction zone, mainly to crack the polycyclic ring hydrocarbons and retain the monocyclic ring hydrocarbons and further break the side chains in each hydrocarbon to form small molecule hydrocarbons. In this way, a large amount of the straight-chain alkanes in the raw material can be converted into gas and light naphtha components, that is, enriched in ethylene raw materials, while the monocyclic ring hydrocarbons are retained in the heavy naphtha fraction, that is, enriched in reforming raw materials. Through simple fractionation, the efficient separation of paraffins and cyclic hydrocarbons can be achieved, increasing the production of high-quality ethylene cracking feedstock while improving the quality of heavy naphtha as catalytic reforming feedstock.

[0043] Petroleum hydrocarbons have a complex composition, mainly including alkanes, cycloalkanes and aromatics. High-quality ethylene feedstocks are small-molecule normal alkanes, and reforming feedstocks are monocyclic cycloalkanes and aromatics. Through research, the inventors found that the technical solution of the present invention can retain monocyclic cyclic hydrocarbons as much as possible and selectively generate small-molecule normal alkanes, thereby achieving the efficient enrichment of small-molecule normal alkanes in light olefin feedstocks, while retaining monocyclic cyclic hydrocarbons in heavy naphtha as much as possible to achieve the efficient enrichment of high-quality reforming feedstocks. In this way, the purpose of greatly improving the yields of chemical feedstocks (i.e., ethylene feedstocks and reforming feedstocks) and the quality of ethylene feedstocks and reforming feedstocks can be achieved, and thus the present invention is completed.

[0044] (2) The heavy naphtha obtained by the method of the present invention has a high content of monocyclic cyclic hydrocarbons. As the feed for the catalytic reforming unit, the alkane cyclization and dehydrogenation unit in the catalytic reforming unit can be cancelled, which can greatly reduce the investment and energy consumption of the catalytic reforming unit. At the same time, since the hydrocracking reaction follows the carbocation reaction mechanism, the side-chain breaking reaction of cyclic hydrocarbons above C9 can be selectively carried out, so that the C6-C8 cyclic hydrocarbons in the product have a high enrichment degree, and the BTX yield can be greatly improved after catalytic reforming and aromatics extraction.

[0045] (3) The present invention selectively converts the alkanes in the overhead oil of the atmospheric tower and the overhead oil of the vacuum tower into small-molecule alkanes. This process consumes a certain amount of hydrogen, but the light hydrocarbons also have a high hydrogen yield as the feedstock for the ethylene unit, and the lower the carbon number, the higher the hydrogen yield. Therefore, most of the hydrogen consumed in the hydrogenation process can be recovered after passing through the ethylene unit. At the same time, the light hydrocarbons as the ethylene feedstock can greatly improve the yields of ethylene, propylene and butadiene, and extend the cleaning cycle of the ethylene unit, significantly improving the economic benefits of the unit. Description of the Drawings

[0046] Figure 1 is a process flow diagram of Examples 1-4 of the present invention;

[0047] Main reference numeral description:

[0048] 1 - Crude oil, 2 - Electrostatic desalting, 3 - Flash tower, 4 - Light naphtha, 5 - Flash tower bottom oil, 6 - Atmospheric tower, 7 - Atmospheric residue, 8 - Atmospheric tower overhead oil, 9 - Vacuum tower, 10 - Vacuum residue, 11 - Vacuum tower overhead oil, 12 - Hydrogen, 13 - First hydrocracking reaction zone, 14 - First hydrocracking reaction effluent, 15 - Second hydrocracking reaction zone, 16 - Second hydrocracking reaction effluent, 17 - Separator, 20 - Gas-phase stream rich hydrogen gas, 21 - Liquid-phase stream, 22 - Fractionating tower, 23 - Gas fraction, 24 - Light naphtha, 25 - Heavy naphtha, 26 - Tail oil. Detailed Embodiments

[0049] The functions and effects of the present invention will be further described below through embodiments, but the following embodiments do not limit the method of the present invention.

[0050] In the present invention, % is the mass fraction unless otherwise specified.

[0051] The total volume space velocity in the examples and comparative examples is the ratio of the fresh feed volume to the total volume of the catalyst.

[0052] The method of the present invention, as Figure 1 shown, includes: crude oil 1 enters the flash tower 3 after electro - desalting 2 and is separated into light naphtha 4 and flash tower bottom oil 5. The flash tower bottom oil 5 enters the atmospheric tower 6 and is separated into atmospheric residue 7 and atmospheric tower top oil 8. The atmospheric residue 7 enters the vacuum tower 9 and is separated into vacuum residue 10 and vacuum tower top oil 11. The atmospheric tower top oil 8, the vacuum tower top oil 11 and hydrogen 12 are mixed and enter the first hydrocracking reaction zone 13 for the first hydrocracking reaction. The effluent 14 from the first hydrocracking reaction enters the second hydrocracking reaction zone 15 for the second hydrocracking reaction. The effluent 16 from the second hydrocracking reaction enters the separator 17. The separated gas - phase hydrogen - rich gas 18 is recycled, and the liquid - phase stream 19 enters the fractionating tower 20, and is fractionated into gas fraction 21, light naphtha 22, heavy naphtha 23 and tail oil 24. The tail oil 24 is recycled to the second hydrocracking reaction zone 15.

[0053] In the present invention, the first hydrocracking catalyst in each example is represented by Cat - A plus a number, such as Cat - A1, Cat - A2, Cat - A3, Cat - A4. The first hydrocracking catalyst is prepared by the conventional active metal saturation impregnation method, and the physical and chemical properties of the obtained catalyst are shown in Table 1.

[0054] In the present invention, the second hydrocracking catalyst in each example is represented by Cat - B plus a number, such as Cat - B1, Cat - B2. The physical and chemical properties of the catalyst are shown in Table 2. In each example, the second hydrocracking catalyst is prepared by the conventional active metal saturation impregnation method. Among them, the properties of the Beta zeolite used in Cat - B2 are as follows: the SiO2 / Al2O3 molar ratio is 30, the specific surface area is 350 m 2 / g, the pore volume is 0.32 cm 3 / g. The properties of the Y zeolite used in Cat - B1 are as follows: the SiO2 / Al2O3 molar ratio is 15, the specific surface area is 400 m 2 / g, the pore volume is 0.30 cm 3 / g. In the present invention, the feedstock oil in each example is crude oil, and its main properties are shown in Table 3.

[0055] In the present invention, in Examples 1 - 3, Cat - B1 and Cat - B2 are filled in sequence along the material flow direction in the second hydrocracking reaction zone.

[0056] In the present invention, the nitrogen content in the reaction fluid stream contacting the first hydrocracking catalyst in each example is below 20 mg / kg.

[0057] In the present invention, the ethylene raw materials in each example refer to ethane, propane, butane and light naphtha obtained in step (3). Ethane, propane, butane and light naphtha can be directly used as raw materials for steam cracking to produce ethylene.

[0058] In the present invention, the distillation range of light naphtha is the liquid component with a boiling point below 60 °C, the distillation range of heavy naphtha is 60 - 175 °C, and the distillation range of tail oil is the component with a boiling point above 175 °C.

[0059] In the present invention, the yield of ethylene raw materials refers to the mass ratio of ethane, propane, butane and light naphtha in the hydrocracking product to the fresh hydrocracking raw materials (the sum of the overhead oil of the atmospheric column and the overhead oil of the vacuum column). The yield of heavy naphtha refers to the mass ratio of heavy naphtha in the hydrocracking product to the fresh hydrocracking raw materials (the sum of the overhead oil of the atmospheric column and the overhead oil of the vacuum column).

[0060] Examples 1 - 4

[0061] The processing method for producing chemical raw materials from the crude oil adopts the following Figure 1 process, including:

[0062] (1) After the crude oil is desalted by electro - desalting, it enters the flash column to separate the light naphtha fraction, and then enters the atmospheric column to separate the overhead oil of the atmospheric column and the atmospheric residue; the atmospheric residue enters the vacuum column to separate the overhead oil of the vacuum column and the vacuum residue;

[0063] (2) The overhead oil of the atmospheric column and the overhead oil of the vacuum column are mixed with hydrogen and successively enter the first hydrocracking reaction zone and the second hydrocracking reaction zone; the first hydrocracking reaction zone is filled with the first hydrocracking catalyst; the second hydrocracking reaction zone is filled with the second hydrocracking catalyst; control the content of C7 + n - paraffin in the effluent of the first hydrocracking reaction and the content of polycyclic naphthenes in the product of the second hydrocracking.

[0064] (3) The effluent of the second hydrocracking reaction zone is subjected to gas - liquid separation to obtain a gas - phase stream and a liquid - phase stream; among them, the gas - phase stream is recycled, and the liquid - phase stream enters the fractionating column to be fractionated into a gas fraction, light naphtha, heavy naphtha and tail oil.

[0065] The process conditions and hydrocracking effects of each example are shown in Table 5.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that the overhead oil of the atmospheric column and the overhead oil of the vacuum column directly enter the second hydrocracking reaction zone after hydrofining.

[0068] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0069] Comparative Example 2

[0070] The difference from Example 1 lies in that: in step (2), the content of n-alkanes in the effluent of the normal paraffin conversion reaction is controlled to be 6% for C7 + The content of normal paraffins is 6%.

[0071] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0072] Comparative Example 3

[0073] The difference from Example 1 lies in that: the catalyst loading sequence in the second hydrocracking reaction zone is different from that in Example 1. In this example, the sequences of catalysts Cat-B1 and Cat-B2 are exchanged. Specifically, in this example, the hydrocracking reaction zone is filled with catalyst Cat-B2 and catalyst Cat-B1 in sequence along the material flow direction.

[0074] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0075] Comparative Example 4

[0076] The difference from Example 1 lies in that: the mass content of aromatics with more than three rings in the vacuum tower top oil is 3.8%.

[0077] In this example, the process conditions and the hydrogenation effect are shown in Table 5.

[0078] Table 1 Physical and Chemical Properties of the First Hydrocracking Catalyst

[0079]

[0080]

[0081] Table 2 Physical and Chemical Properties of the Second Hydrocracking Catalyst

[0082] Catalyst properties Cat-B1 Cat-B2 <![CDATA[Pore volume, cm 3 / g]]> 0.35 0.35 <![CDATA[Specific surface area, m 2 / g]]> 300 300 Catalyst composition and content Beta, wt% - 50 Y, wt% 30 - <![CDATA[MoO3, wt%]]> 25 10 NiO, wt% 5 5 Alumina, wt% 40 35

[0083] Table 3 Main Properties of the Feedstock Oil

[0084] Item Crude oil <![CDATA[Density (20 °C) / g·cm -3 > 0.9515 API, ° 16.8 Carbon residue, % 11.52 Ash content, % 0.067 Sulfur content, % 2.69 Nitrogen content, % 0.42 Resin, % 14.27 Asphaltene, % 6.61 <![CDATA[Metal analysis / μg·g -1 > 60

[0085] Table 4 Atmospheric / Vacuum Distillation Process Conditions and Main Properties of the Atmospheric / Vacuum Tower Top Oil

[0086]

[0087] Continued Table 4

[0088]

[0089]

[0090] Table 5 Hydrogenation effect

[0091]

[0092] Continued Table 5

[0093]

[0094]

[0095] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A processing method for producing chemical raw materials from crude oil, characterized in that, The method includes: (1) After the crude oil is desalted electrically, it enters a flash column to separate out the light naphtha fraction, and then enters an atmospheric column to obtain the overhead oil of the atmospheric column and atmospheric residue; the atmospheric residue enters a vacuum column to obtain the overhead oil of the vacuum column and vacuum residue; wherein, the initial boiling point of the overhead oil of the atmospheric column is 50°C to 80°C, and the final boiling point is 300°C to 400°C; the initial boiling point of the overhead oil of the vacuum column is 300 to 360°C, and the final boiling point is 460°C to 520°C; (2) In the presence of hydrogen, the overhead oil from the atmospheric column and the overhead oil from the vacuum column obtained in step (1) are mixed and enter the first hydrocracking reaction zone, selectively cracking the n-alkanes in the first hydrocracking product to obtain the first hydrocracking product; wherein, the mass content of C7 + n-alkanes in the first hydrocracking product is controlled to be 0.1% - 5.0%; (3) In the presence of hydrogen, the first hydrocracking product enters a second hydrocracking reaction zone to obtain a second hydrocracking product containing monocyclic cyclic hydrocarbons; (4) The second hydrocracking product is separated and fractionated to obtain a gas fraction, light naphtha, heavy naphtha and tail oil; The mass content of aromatics with more than three rings in the overhead oil of the vacuum column in step (1) is not higher than 1.0%; In step (2), the first hydrocracking reaction zone is filled with a first hydrocracking catalyst; the first hydrocracking catalyst includes an active metal component and a carrier; the carrier includes a molecular sieve having selective cracking of normal paraffins, and the molecular sieve is selected from one or more of ZSM-5 molecular sieve, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 and ZSM-38 molecular sieves; the active metal component includes at least one of Group VIB metals and Group VIII metals; For the first hydrocracking catalyst, based on the weight of the catalyst, the content of the Group VIB metal in terms of oxide is 5.0% to 15.0%, the content of the Group VIII metal in terms of oxide is 2.0% to 5.0%, and the content of the carrier is 80.0% to 93.0%; in the carrier of the first hydrocracking catalyst, based on the weight of the carrier, the content of the binder is 8% to 60%, and the content of the molecular sieve is 40% to 92%; In step (3), the second hydrocracking reaction zone is filled with a second hydrocracking catalyst; the second hydrocracking catalyst includes a cracking component, a hydrogenation component and a binder; in step (3), the second hydrocracking reaction zone is filled with a catalyst with Y molecular sieve as the cracking component and a catalyst with Beta molecular sieve as the cracking component in sequence along the material flow direction; For the second hydrocracking catalyst, based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component in terms of oxide is 5wt% to 40wt%; the content of the cracking component is 10wt% to 80wt%; the content of the binder is 5wt% to 85wt%; The chemical raw materials include ethane, propane, butane, light naphtha and heavy naphtha. Among them, heavy naphtha is used as a reforming raw material to produce BTX, and ethane, propane, butane and light naphtha are used as raw materials for producing lower olefins.

2. The method according to claim 1, wherein The properties of the crude oil in step (1) are as follows: the density is 0.80 g / cm 3 ~1.10 g / cm 3 ; the nitrogen mass content is 0.1% - 0.6%; the sulfur mass content is 1% - 6%; the metal content is 10 mg / kg - 100 mg / kg.

3. The method according to claim 1, wherein The properties of the crude oil in step (1) are as follows: the density is 0.85 g / cm 3 ~0.95 g / cm 3 ; the nitrogen mass content is 0.2% - 0.4%; the sulfur mass content is 2% - 4%; the metal content is 20 mg / kg - 60 mg / kg.

4. The method according to claim 1, wherein The initial boiling point of the overhead oil of the atmospheric column in step (1) is 60°C to 70°C, and the final boiling point is 320°C to 340°C; And / or, the initial boiling point of the overhead oil of the vacuum column is 320 to 340°C, and the final boiling point is 480°C to 500°C.

5. The method according to claim 1, wherein In step (1), the atmospheric distillation conditions are as follows: the top pressure is 0.04 MPa to 0.12 MPa; the atmospheric distillation feed temperature is 330 °C to 390 °C; and / or, the vacuum distillation conditions are as follows: the top pressure is 0.5 kPa to 5 kPa; the vacuum distillation feed temperature is 350 °C to 460 °C.

6. The method according to claim 1, wherein In step (1), the atmospheric distillation conditions are as follows: the top pressure is 0.06 MPa to 0.10 MPa; the atmospheric distillation feed temperature is 350 °C to 370 °C; and / or, the vacuum distillation conditions are as follows: the top pressure is 1 kPa to 3 kPa; the vacuum distillation feed temperature is 380 °C to 420 °C.

7. The method according to claim 1, wherein In the overhead oil of the vacuum tower in step (1), the mass content of aromatics with more than three rings is 0.2% to 0.6%; And / or, the mass content of C7 n-alkanes in the first hydrocracking product of step (2) is controlled to be 1.0% to 3.0%. + ​ 8. The method according to claim 1, wherein In the first hydrocracking catalyst in step (2), the molecular sieve is ZSM-5 molecular sieve; and / or, the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is cobalt and / or nickel.

9. The method according to claim 1, wherein In step (2), the reaction pressure in the first hydrocracking reaction zone is 10 to 16 MPa.

10. The method according to claim 1, wherein In step (2), the reaction pressure in the first hydrocracking reaction zone is 12 to 14 MPa.

11. The method according to claim 1, wherein The reaction conditions in the first hydrocracking reaction zone in step (2) are as follows: the average reaction temperature is 250~450°C; the liquid hourly space velocity is 0.1~15.0 h -1 ; the hydrogen-oil volume ratio is 100:1~2500:

1.

12. The method according to claim 1, wherein The reaction conditions in the first hydrocracking reaction zone in step (2) are as follows: the average reaction temperature is 300~400°C; the liquid hourly space velocity is 1.0~5.0 h -1 ; the hydrogen-oil volume ratio is 400:1~2000:

1.

13. The method according to claim 1, characterized in that, In the second hydrocracking catalyst in step (3), based on the weight of the second hydrocracking catalyst, the content of the hydrogenation component in terms of oxide is 10 wt% to 30 wt%; the content of the cracking component is 20 wt% to 60 wt%; the content of the binder is 10 wt% to 50 wt%; and / or, in the second hydrocracking catalyst, the hydrogenation component is at least one of a metal, a metal oxide, and a metal sulfide of the active metal component; the active metal component includes a Group VIB metal and / or a Group VIII metal; the active metal component is at least one of iron, chromium, molybdenum, tungsten, cobalt, and nickel; and / or, in the second hydrocracking catalyst, the binder is alumina and / or silica; and / or, the volume ratio of the catalyst with Y molecular sieve as the cracking component to the catalyst with Beta molecular sieve as the cracking component is 5:1 to 1:

2.

14. The method according to claim 13, wherein The volume ratio of the catalyst with Y molecular sieve as the cracking component to the catalyst with Beta molecular sieve as the cracking component is 3:1 to 1:

1.

15. The method according to claim 1, wherein In step (3), the reaction pressure in the second hydrocracking reaction zone is 10 to 16 MPa.

16. The method according to claim 1, characterized in that, In step (3), the reaction pressure in the second hydrocracking reaction zone is 12 to 14 MPa.

17. The method according to claim 1, characterized in that In step (3), the reaction conditions in the second hydrocracking reaction zone are as follows: the average reaction temperature is 250 to 450 °C; the liquid hourly space velocity is 0.1 to 15.0 h -1 ; the hydrogen-oil volume ratio is 100:1 to 2500:

1.

18. The method according to claim 1, characterized in that, In step (3), the reaction conditions in the second hydrocracking reaction zone are as follows: the average reaction temperature is 300~400°C; the liquid hourly space velocity is 1.0~5.0 h -1 ; the hydrogen-oil volume ratio is 400:1~2000:

1.

19. The method according to claim 1, wherein The first hydrocracking reaction zone and the second hydrocracking reaction zone adopt the same pressure.

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