Catalytic conversion method for increasing yield of low-carbon olefins and light aromatic hydrocarbons

Abstract

The invention relates to a catalytic conversion method for increasing the yield of low-carbon olefins and light aromatic hydrocarbons, which comprises the following steps: contacting a diesel oil raw material with a hydrogenation catalyst in a hydrogen-containing atmosphere for hydrogenation reaction to obtain a hydrogenation product; feeding the hydrogenation product into a fluidized bed reactor to be in contact with a catalytic conversion catalyst for catalytic conversion reaction to obtain an oil agent mixture; and carrying out gas-solid separation on the oil agent mixture to obtain reaction oil gas and a spent catalyst, and separating the reaction oil gas to obtain ethylene, propylene and light aromatic hydrocarbon. According to the method provided by the invention, the catalytic cracking performance of the diesel oil can be improved, and the yield of low-carbon olefins and light aromatic hydrocarbons is increased.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals, specifically relating to a catalytic conversion method for increasing the production of low-carbon olefins and light aromatics. Background Technology

[0002] Low-carbon olefins (ethylene, propylene, etc.) are important basic feedstocks in the petrochemical industry, mainly used in the production of polymers, oxygen-containing compounds, and chemical intermediates, and widely applied in polymer, pesticide, pharmaceutical, and fine chemical industries. Traditional petrochemical industry is based on steam cracking to produce ethylene. Currently, one of the main units used in refining and chemical enterprises to produce propylene is the catalytic cracking unit. The main feedstocks for catalytic cracking units include naphtha, diesel oil, wax oil, and residual oil. However, catalytic cracking units using diesel oil as feedstock have relatively low propylene yields.

[0003] Light aromatics (benzene, toluene, and xylene, abbreviated as BTX) are also important organic chemical raw materials, widely used in the production of chemical products such as synthetic fibers, plastics, and rubber, as well as fine chemicals. Currently, light aromatics are mainly obtained through naphtha catalytic reforming, and naphtha is also the main raw material for the production of low-carbon olefins. With the increasing weight and quality of crude oil, naphtha supply is tight, and there is an urgent need to provide a method for producing aromatics from alternative raw materials.

[0004] Current technologies mainly rely on heavy oil catalytic cracking, while catalytic cracking technology using light feedstocks such as naphtha is still in its early stages. Straight-run diesel accounts for a very small proportion of the cracking feedstock. Therefore, it is necessary to increase the proportion of diesel feedstock in the production of low-carbon olefins and light aromatics.

[0005] CN111607425A discloses a method for catalytic cracking of straight-run diesel. This method involves first adding acidic substances to the straight-run diesel to remove basic nitrogen compounds, and then simultaneously introducing the straight-run diesel and an inert dilution gas into a reactor to carry out a catalytic cracking reaction to generate low-carbon olefins.

[0006] CN111303940A discloses a method for processing straight-run diesel. This method involves removing aromatics from the straight-run diesel using solvent extraction or adsorption separation to obtain aromatic-rich components and dearomatic components. The aromatic-rich components are then hydrotreated using a diesel hydrotreating process or an aromatics hydrotreating process to obtain diesel or gasoline products and benzene products. Finally, the dearomatic components are subjected to steam cracking to obtain olefin products. This method simultaneously utilizes both the aromatic-rich and dearomatic components, improving the utilization rate of straight-run diesel.

[0007] However, existing methods for producing low-carbon olefins from straight-run diesel fuel still have problems such as high diesel conversion reaction temperature and the need to improve the yield of low-carbon olefins. Summary of the Invention

[0008] The purpose of this invention is to further improve the yield of low-carbon olefins and light aromatics.

[0009] To achieve the above objectives, the present invention provides a catalytic conversion method for increasing the production of low-carbon olefins and light aromatics, the method comprising: Diesel feedstock is contacted with a hydrogenation catalyst in a hydrogen-containing atmosphere to carry out a hydrogenation reaction, yielding hydrogenated products; The hydrogenation product is fed into a fluidized bed reactor and contacted with a catalytic conversion catalyst to carry out a catalytic conversion reaction, thereby obtaining an oil-agent mixture; The oil mixture is subjected to gas-solid separation to obtain reactive oil gas and catalyst to be generated. The reactive oil gas is then separated to obtain ethylene, propylene and light aromatics.

[0010] Optionally, the conditions for the hydrogenation reaction include: a hydrogen partial pressure of 3-12 MPa, a reaction temperature of 260-450 °C, and a hydrogen catalyst-to-hydrogen product ratio of 400-1600 Nm. 3 / m 3 The liquid hourly space velocity (LHSV) of the diesel feedstock is 0.3~4.0 h⁻¹. -1 The hydrogen content in the hydrogen-containing atmosphere is 85-100% by volume; preferably, the saturated hydrocarbon content in the hydrogenation product is not less than 80% by weight; and the distillation range of the hydrogenation product is in the range of 180-410 °C.

[0011] Optionally, the hydrogenation catalyst comprises a support and an active metal component supported on the support; the support is selected from one or more of alumina, silica, titanium dioxide, magnesium oxide, beryllium oxide, zirconium oxide, and molecular sieves; and / or the active metal component comprises at least one metal element selected from Group VIB and at least one metal element selected from Group VIII; based on the total weight of the hydrogenation catalyst, the content of the at least one metal element selected from Group VIB, calculated as oxide, is 1 to 30% by weight, and the content of the at least one metal element selected from Group VIII, calculated as oxide, is 3 to 35% by weight.

[0012] Optionally, the diesel feedstock has a distillation range of 180~410℃; optionally, the diesel feedstock includes at least one of straight-run diesel and secondary processed diesel fractions; the secondary processed diesel fraction is selected from one or more of coking diesel and catalytic cracking diesel fractions.

[0013] Optionally, the conditions for the catalytic conversion reaction include: a reaction temperature of 500~750 ℃, preferably 580~680 ℃; a reaction time of 1~10 seconds, preferably 1~8 seconds; a reaction pressure of 0.05~1 MPa; and a weight ratio of the catalytic conversion catalyst to the hydrogenation product of 1~100:1, preferably 10~50:1.

[0014] Optionally, based on the total weight of the catalytic conversion catalyst, the catalytic conversion catalyst comprises 1-60% by weight of zeolite, 5-99% by weight of inorganic oxides, and 0-70% by weight of clay; wherein the zeolite is selected from mesoporous zeolite and optionally macroporous zeolite; based on the total weight of the zeolite, the content of mesoporous zeolite is 50-100% by weight, and the content of macroporous zeolite is 0-50% by weight; preferably, based on the total weight of the zeolite, the content of mesoporous zeolite is 70-100% by weight, and the content of macroporous zeolite is 0-30% by weight.

[0015] Optionally, the mesoporous zeolite is selected from ZSM series zeolites and / or ZRP series zeolites; the macroporous zeolite is selected from one or more of rare earth Y zeolite, rare earth hydrogen Y zeolite, ultrastable Y zeolite and high silica Y zeolite; preferably, the ZSM series zeolite is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48.

[0016] Optionally, the fluidized bed reactor is selected from one or more of the following: riser reactor, constant linear velocity fluidized bed reactor, constant diameter fluidized bed reactor, upward conveyor line, and downward conveyor line; the riser reactor is selected from one or more of the following: constant diameter riser reactor, constant linear velocity riser reactor, and variable diameter riser reactor, preferably a constant diameter riser reactor.

[0017] Optionally, the method further includes: injecting water vapor into the fluidized bed reactor; the mass ratio of the water vapor to the hydrogenation product is 0.01 to 1:1, preferably 0.05 to 0.5:1.

[0018] Optionally, the method further includes: regenerating the spent catalyst by coking to obtain a regenerated catalyst; and returning at least a portion of the regenerated catalyst to the fluidized bed reactor.

[0019] Through the above technical solution, the present invention improves the catalytic cracking performance of diesel fuel by hydrogenating the diesel feedstock and catalytically cracking the hydrogenated products, thereby increasing the yield of low-carbon olefins and light aromatics.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a catalytic conversion method in some embodiments of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Pipeline; 2. Pipeline; 3. Hydrogenation reactor; 4. Pipeline; 5. Pipeline; 6. Pipeline; 7. Regeneration slide valve; 8. Stripping section; 9. Pipeline; 10. Settler; 11. Cyclone separator; 12. Gas collection chamber; 13. Main oil and gas pipeline; 14. Waiting slide valve; 15. Waiting inclined tube; 16. Regeneration inclined tube; 17. Pipeline; 18. Air distributor; 19. Regenerator; 20. Regenerator cyclone separator; 21. Flue gas duct; 22. Fluidized bed reactor; Detailed Implementation The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0023] This invention provides a catalytic conversion method for increasing the production of low-carbon olefins and light aromatics, the method comprising: Diesel feedstock is contacted with a hydrogenation catalyst in a hydrogen-containing atmosphere to carry out a hydrogenation reaction, yielding hydrogenated products; The hydrogenation product is fed into a fluidized bed reactor and contacted with a catalytic conversion catalyst to carry out a catalytic conversion reaction, thereby obtaining an oil-agent mixture; The oil mixture is subjected to gas-solid separation to obtain reactive oil gas and catalyst to be generated. The reactive oil gas is then separated to obtain ethylene, propylene and light aromatics.

[0024] The technical solution of this invention improves the catalytic cracking performance of diesel fuel by hydrogenating the diesel feedstock and catalytically cracking the hydrogenation products, thereby increasing the yield of low-carbon olefins and light aromatics.

[0025] In some embodiments of the present invention, the diesel feedstock is a hydrocarbon mixture with a boiling range of 180~410 °C according to ASTM D86, and the diesel feedstock includes at least one of straight-run diesel and secondary processed diesel fractions; the secondary processed diesel fraction is selected from one or more of coking diesel and catalytic cracking diesel fractions.

[0026] The straight-run diesel is mainly a straight-run diesel fraction obtained by fractionating intermediate-base crude oil, naphthenic crude oil, naphthenic-intermediate crude oil, or intermediate-naphthenic crude oil.

[0027] In this invention, the hydrogenation reaction includes: contacting diesel feedstock with hydrogen and a hydrogenation catalyst under hydrogenation reaction conditions to carry out the reaction. The hydrogenation reactor is preferably a fixed-bed reactor.

[0028] In some embodiments of the present invention, the conditions for the hydrogenation reaction include: a hydrogen partial pressure of 3-12 MPa, a reaction temperature of 260-450 °C, and a product ratio of the hydrogenation catalyst to hydrogen of 400-1600 Nm. 3 / m 3 The liquid hourly space velocity (LHSV) of the diesel feedstock is 0.3~4.0 h⁻¹. -1 The hydrogen content in the hydrogen-containing atmosphere is 85-100% by volume.

[0029] Diesel hydrotreating can involve reactions such as hydrodesulfurization, hydrodenitrogenation, aromatic saturation, and hydrodemetallization. One important objective is to saturate at least a portion of the polycyclic aromatic hydrocarbons (PAHs) in the diesel fraction, converting the difficult-to-crack PAHs into easily crackable saturated hydrocarbons, thereby improving the catalytic cracking performance of diesel and increasing the yields of ethylene, propylene, and light aromatics. Through diesel hydrotreating, the saturated hydrocarbon content in the hydrotreating product is not less than 80% by weight, and the preferred distillation range is in the range of 180–410 °C.

[0030] In some embodiments of the present invention, the hydrogenation catalyst includes a support and an active metal component supported on the support.

[0031] In some preferred embodiments of the present invention, the carrier is selected from one or more of alumina, silicon oxide, titanium oxide, magnesium oxide, beryllium oxide, zirconium oxide, and molecular sieves.

[0032] In some preferred embodiments of the present invention, the active metal component comprises at least one metal element selected from Group VIB and at least one metal element selected from Group VIII; based on the total weight of the hydrogenation catalyst, the content of the at least one metal element selected from Group VIB, calculated as oxide, is 1 to 30% by weight, and the content of the at least one metal element selected from Group VIII, calculated as oxide, is 3 to 35% by weight.

[0033] The diesel catalytic conversion method provided by the present invention can be carried out in conventional reactors in the art. In some embodiments of the present invention, the fluidized bed reaction is selected from one or more combinations of riser reactors, constant linear velocity fluidized bed reactors, constant diameter fluidized bed reactors, upward conveying lines and downward conveying lines; the combination includes series and / or parallel connections.

[0034] In a preferred embodiment of the present invention, the diesel catalytic conversion provided by the present invention is carried out in a riser reactor. The riser reactor is selected from one or more of a constant-diameter riser reactor, a constant-linear-velocity riser reactor, and a variable-diameter riser reactor, preferably a constant-diameter riser reactor. When the reactor is a riser reactor, the reaction temperature refers to the outlet temperature of the riser reactor or a certain reaction zone of the riser reactor.

[0035] In some embodiments of the present invention, the conditions for the catalytic conversion reaction include: a reaction temperature of 500-750 °C, preferably 580-680 °C; a reaction time of 1-10 seconds, preferably 1-8 seconds; a reaction pressure of 0.05-1 MPa; and a weight ratio of the catalytic conversion catalyst to the hydrogenation product of 1-100:1, preferably 10-50:1. By controlling the conditions of the catalytic conversion reaction, it is beneficial to fully catalytically crack the hydrogenation product, thereby increasing the yield of low-carbon olefins and light aromatics while reducing the yield of by-products.

[0036] In some embodiments of the present invention, based on the total weight of the catalytic conversion catalyst, the catalytic conversion catalyst comprises 1-60% by weight of zeolite, 5-99% by weight of inorganic oxides, and 0-70% by weight of clay; wherein the zeolite is selected from mesoporous zeolite and optionally macroporous zeolite; based on the total weight of the zeolite, the content of mesoporous zeolite is 50-100% by weight, and the content of macroporous zeolite is 0-50% by weight; preferably, based on the total weight of the zeolite, the content of mesoporous zeolite is 70-100% by weight, and the content of macroporous zeolite is 0-30% by weight.

[0037] In some embodiments of the present invention, the mesoporous zeolite is selected from ZSM series zeolites and / or ZRP series zeolites.

[0038] In this invention, the mesoporous zeolite and macroporous zeolite are defined according to conventional definitions in the art, namely, the average pore size of mesoporous zeolite is 0.5~0.6nm and the average pore size of macroporous zeolite is 0.7~1.0nm.

[0039] In some preferred embodiments of the present invention, the macroporous zeolite is selected from one or more of rare earth Y (REY) zeolite, rare earth hydrogen Y (REHY) zeolite, ultrastable Y zeolite, and high-silica Y zeolite. The mesoporous zeolite can be selected from zeolites with an MFI structure, such as ZSM series zeolites and / or ZRP zeolite. The aforementioned mesoporous zeolites can also be modified with non-metallic elements such as phosphorus and / or transition metal elements such as iron, cobalt, and nickel. For a more detailed description of ZRP, see US5,232,675. The ZSM series zeolite is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, and ZSM-48, or a mixture of one or more zeolites with similar structures. For a more detailed description of ZSM-5, see US3,702,886.

[0040] In some preferred embodiments of the present invention, the inorganic oxide is used as a binder, preferably silicon dioxide (SiO2) and / or aluminum oxide (Al2O3); the clay is used as a matrix (i.e. carrier), preferably kaolin and / or hydrous kaolin.

[0041] In the diesel catalytic conversion method provided by this invention, the catalyst to be generated is first separated from the reaction oil and gas to obtain the catalyst to be generated and the reaction oil and gas. Then, the obtained reaction oil and gas is separated by a subsequent separation system (e.g., a cyclone separator) to obtain dry gas, liquefied petroleum gas, cracked gasoline and cracked diesel fractions. Then, the dry gas and liquefied petroleum gas are further separated by a gas separation device to obtain ethylene, propylene and other components. The cracked gasoline is separated by aromatics extraction to obtain light aromatics. The method for separating ethylene, propylene and other components from the reaction products is similar to the conventional technical methods in the field. This invention does not limit this and will not describe it in detail here.

[0042] In some embodiments of the present invention, the method further includes: injecting water vapor into the fluidized bed reactor; the water vapor is preferably injected in the form of atomized steam, and the mass ratio of the water vapor to the hydrogenation product is 0.01~1:1, preferably 0.05~0.5:1.

[0043] In some embodiments of the present invention, the method further includes: regenerating the spent catalyst by coking to obtain a regenerated catalyst; and returning at least a portion of the regenerated catalyst to the fluidized bed reactor.

[0044] During the regeneration process, oxygen-containing gas is generally introduced from the bottom of the regenerator. For example, air can be introduced into the regenerator. After the catalyst is regenerated, it comes into contact with oxygen and is burned off. The flue gas generated after the catalyst is burned off is separated into gas and solid at the top of the regenerator and then enters the subsequent energy recovery system.

[0045] In some embodiments of the present invention, the regeneration operating conditions of the catalyst to be regenerated are as follows: the regeneration temperature is 550~750℃, preferably 600~730℃, more preferably 650~700℃; the apparent linear velocity of the gas is 0.5~3 m / s, preferably 0.8~2.5 m / s, more preferably 1~2 m / s; and the average residence time of the catalyst to be regenerated is 0.6~3 minutes, preferably 0.8~2.5 minutes, more preferably 1~2 minutes. Preferably, the process further includes stripping the regenerated catalyst (generally using steam stripping) to remove impurities such as gases.

[0046] In some embodiments of the present invention, the method further includes: preheating the feedstock oil to a gaseous state before contacting it with the catalytic cracking catalyst, for example, preheating the feedstock oil to 300~450°C before introducing it into the reactor to contact with the catalytic cracking catalyst, preferably preheating it to 350~420°C.

[0047] Figure 1 The illustration shows a preferred embodiment of the present invention, which is described below in conjunction with... Figure 1 The flowchart illustrates the method of the present invention.

[0048] Diesel fuel enters the top of the hydrogenation reactor 3 via pipeline 1, where it reacts with hydrogen from pipeline 2 on the hydrogenation catalyst to obtain hydrogenation products.

[0049] The pre-lifting medium enters the fluidized bed reactor 22 from the bottom via pipeline 6. The regenerated catalyst from pipeline 16, after being regulated by the regeneration slide valve 7, enters the fluidized bed reactor 22 and accelerates upwards along the riser pipe under the lifting action of the pre-lifting medium. The hydrogenation product, along with atomized steam from pipeline 4, is injected into the fluidized bed reactor 22 via pipeline 5, mixing with the existing stream in the reactor. The feedstock oil contacts the regenerated catalyst and undergoes a catalytic conversion reaction. The resulting reaction oil and gas, along with the deactivated spent catalyst, enter the cyclone separator 11 in the settling tank 10 for separation. The separated reaction oil and gas enter the gas collection chamber 12, while the spent catalyst fines return to the settling tank 10. The spent catalyst in the settling tank 10 flows to the stripping section 8, where it contacts steam from pipeline 9 for stripping. The reaction oil and gas stripped from the spent catalyst enters the gas collection chamber 12 after separation by the cyclone separator 11. After stripping, the spent catalyst enters the regenerator 19 via pipeline 15 and is regulated by the spent catalyst slide valve 14. Air from pipeline 17 is distributed by air distributor 18 and enters the regenerator 19, burning off the coke on the spent catalyst in the dense phase bed at the bottom of the regenerator 19, thus regenerating the deactivated spent catalyst. The flue gas then enters the subsequent energy recovery system via the upper gas flue gas duct 21 of the cyclone separator 20. The pre-lifting medium can be dry gas, steam, or a mixture thereof.

[0050] The regenerated catalyst is circulated back to the bottom of the fluidized bed reactor 22 via pipeline 16 and regeneration slide valve 7, with the catalyst circulation rate controlled. The reaction oil and gas in the gas collection chamber 12 enters the subsequent separation system via the large oil and gas pipeline 13, where gaseous products, liquid products, and coke can be obtained. Further separation can yield products such as ethylene, propylene, and light aromatics.

[0051] The present invention will be further described in detail below through embodiments, but these embodiments are not intended to limit the invention. All raw materials used in the embodiments are commercially available.

[0052] In the following examples, the catalytic conversion reaction was carried out in a medium-sized catalytic cracking unit, and the hydrogenation reaction was carried out in a medium-sized hydrogenation reaction unit. The fluidized bed reactor was a riser reactor of constant diameter.

[0053] The feedstock used in the examples and comparative examples is diesel oil, and its properties are shown in Table 1.

[0054] The same catalytic conversion catalyst was used in the examples and comparative examples. The commercial brand name is DMMC-2, which was produced by Sinopec Catalyst Co., Ltd. Qilu Branch. The properties of the catalyst are shown in Table 2.

[0055] The hydrogenation catalyst used in the examples comprises alumina and metallic nickel supported on alumina, with a nickel content of 7.45% by weight, based on the total weight of the oxide and the hydrogenation catalyst.

[0056] Table 1

[0057] Table 2

[0058] Example 1 This embodiment adopts Figure 1 The flowchart shown is used for experimentation. The specific steps are as follows: The extracted product was introduced into hydrogenation reactor 3 for hydrogenation reaction to obtain the hydrogenated product. The hydrogenation reaction conditions and the distribution of the hydrogenated product are shown in Table 4.

[0059] The preheated hydrogenation product is introduced into the bottom of riser reactor 22, where it comes into contact with the regenerated catalyst from the regenerator via pipeline 16 for catalytic conversion. The reaction oil from the riser reactor outlet is then introduced into a cyclone separator for separation, yielding the spent catalyst and reaction oil / gas. The separated spent catalyst is then stripped in the stripping section, and finally introduced into the regenerator for coke burn-off regeneration.

[0060] The separated reaction oil and gas are cut according to the distillation range in the separation system to obtain ethylene, propylene and light aromatics.

[0061] The reaction conditions and catalytic conversion product distribution of the riser reactor are shown in Table 3.

[0062] Example 2 The method used in this embodiment is basically similar to that in Example 1, except that the hydrogenation reaction conditions are different. The hydrogenation reaction conditions, catalytic conversion reaction conditions, and product distribution are shown in Table 3.

[0063] Example 3 The method used in this embodiment is basically similar to that in Example 1, except that the hydrogenation reaction conditions and catalytic conversion reaction conditions are different. The hydrogenation reaction conditions, catalytic conversion reaction conditions and product distribution are shown in Table 3.

[0064] Example 4 The method used in this embodiment is basically similar to that in Example 1, except that the catalytic conversion reaction conditions are different; the hydrogenation reaction conditions, catalytic conversion reaction conditions, and product distribution are shown in Table 3.

[0065] Example 5 The method used in this embodiment is basically similar to that in Example 1, except that the catalytic conversion reaction conditions are different; the hydrogenation reaction conditions, catalytic conversion reaction conditions, and product distribution are shown in Table 3.

[0066] Comparative Example 1 The method used in this comparative example is basically similar to that in Example 1, except that the diesel feedstock is directly introduced into the riser reactor for catalytic conversion. The catalytic conversion reaction conditions and product distribution are shown in Table 3.

[0067] Table 3

[0068] As can be seen from the table above, the method provided by the present invention can improve the catalytic cracking performance of diesel fuel and increase the yield of low-carbon olefins and light aromatics in the products.

[0069] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0070] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0071] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A catalytic conversion process for the increased production of lower olefins and light aromatics, characterized in that, The method comprises: contacting a diesel feedstock with a hydrogenation catalyst in a hydrogen-containing atmosphere to perform a hydrogenation reaction, to obtain a hydrogenation product; feeding the hydrogenation product into a fluidized bed reactor to contact with a catalytic conversion catalyst to perform a catalytic conversion reaction, to obtain an oil-agent mixture; performing gas-solid separation on the oil-agent mixture to obtain a reaction oil gas and spent catalyst, and separating the reaction oil gas to obtain ethylene, propylene and light aromatic hydrocarbons.

2. The method of claim 1, wherein, The conditions of the hydrogenation reaction include: hydrogen partial pressure of 3-12 MPa, reaction temperature of 260-450 ℃, and product ratio of the hydrogenation catalyst to hydrogen of 400-1600 Nm 3 / m 3 ; and liquid hourly space velocity of the diesel oil raw material of 0.3-4.0 h -1 ; The content of hydrogen in the hydrogen-containing atmosphere is 85-100% by volume; Preferably, the content of saturated hydrocarbons in the hydrogenation product is not less than 80% by weight, and the distillation range of the hydrogenation product is in the range of 180-410 ℃.

3. The method of claim 1, wherein, The hydrogenation catalyst comprises a carrier and an active metal component supported on the carrier; The carrier is selected from one or more of alumina, silica, titania, magnesia, beryllia, zirconia and molecular sieve; and / or the active metal component comprises at least one metal element selected from Group VIB and at least one metal element selected from Group VIII; The content of the at least one metal element selected from Group VIB is 1-30% by weight based on the total weight of the hydrogenation catalyst in terms of oxide, and the content of the at least one metal element selected from Group VIII is 3-35% by weight based on the total weight of the hydrogenation catalyst in terms of oxide.

4. The method of claim 1, wherein, The distillation range of the diesel feedstock is 180-410 ℃; Optionally, the diesel feedstock comprises at least one of straight-run diesel and a secondary processed diesel fraction; the secondary processed diesel fraction is selected from one or more of coking diesel and catalytically cracked diesel fraction.

5. The method of claim 1, wherein, The conditions of the catalytic conversion reaction include: the reaction temperature is 500-750 ℃, preferably 580-680 ℃; the reaction time is 1-10 seconds, preferably 1-8 seconds; the reaction pressure is 0.05-1 MPa; the weight ratio of the catalytic conversion catalyst to the hydrogenation product is 1-100:1, preferably 10-50:

1.

6. The method of claim 1, wherein, The catalytic conversion catalyst comprises 1-60% by weight of zeolite, 5-99% by weight of inorganic oxide and 0-70% by weight of clay based on the total weight of the catalytic conversion catalyst; The zeolite is selected from medium pore zeolite and optionally large pore zeolite; the content of the medium pore zeolite is 50-100% by weight based on the total weight of the zeolite, and the content of the large pore zeolite is 0-50% by weight based on the total weight of the zeolite; Preferably, the content of the medium pore zeolite is 70-100% by weight based on the total weight of the zeolite, and the content of the large pore zeolite is 0-30% by weight based on the total weight of the zeolite.

7. The method of claim 6, wherein, The medium pore zeolite is selected from ZSM series zeolite and / or ZRP series zeolite; the large pore zeolite is selected from one or more of rare earth Y zeolite, rare earth hydrogen Y zeolite, ultrastable Y zeolite and high-silicon Y zeolite; Preferably, the ZSM series zeolite is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48.

8. The method of claim 1, wherein, The fluidized bed reactor is selected from one or more than two combinations of a riser reactor, an isokinetic fluidized bed reactor, an equal-diameter fluidized bed reactor, an upward conveying line and a downward conveying line. The riser reactor is selected from one or more of an equal-diameter riser reactor, an isokinetic riser reactor and a variable-diameter riser reactor, preferably an equal-diameter riser reactor.

9. The method of claim 1, wherein, The method further comprises: injecting steam into the fluidized bed reactor; and the mass ratio of the steam to the hydrogenation product is 0.01-1:1, preferably 0.05-0.5:

1.

10. The method of claim 1, wherein, The method further comprises: performing coke-burning regeneration on the spent catalyst to obtain regenerated catalyst; and returning at least part of the regenerated catalyst to the fluidized bed reactor.

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