Shale oil hydrocracking method and system

Abstract

The invention relates to a shale oil hydrocracking method, which comprises: S1, in the presence of a first hydrofining catalyst, carrying out a hydrogenation saturation reaction on shale oil in a hydrogenation pretreatment device to obtain a first product; s2, in the presence of a second hydrofining catalyst, carrying out hydrofining reaction on the first product in a hydrofining device to obtain a second product; s3, introducing the second product into a separation device for separation, introducing a part of separated diesel oil and hydrogen into a hydrocracking device to be in contact with a catalyst for hydrocracking reaction, and introducing a hydrocracking reaction product into the separation device for separation; the catalyst in the hydrocracking device comprises a hydrocracking catalyst and a third hydrorefining catalyst. The method disclosed by the invention can be used for simultaneously producing the high-quality ethylene cracking raw material and the low-condensation-point diesel oil by taking the shale oil as the raw oil, and can effectively avoid the negative influence of ammonia adsorption on the cracking activity of the hydrocracking agent.

Description

Technical Field

[0001] This application relates to a method and system for hydrocracking shale oil. Background Technology

[0002] Shale oil, a liquid product obtained through the dry distillation and pyrolysis of the oil source material in oil shale, is used similarly to crude oil, and can be used as fuel oil after certain processing. Compared to crude oil, shale oil generally has a higher nitrogen content and contains a large amount of unsaturated hydrocarbons, such as olefins and dienes, but generally lower levels of aromatics. Unsaturated hydrocarbons and heteroatomic hydrocarbons are the main reasons for the increased gum content, poor stability, and darker color of shale oil. Currently, the main use of shale oil is for blending with marine diesel or heavy marine fuel as marine fuel oil. Shale oil can also be processed through hydrotreating and other processes to be used as a blending component for light oil products such as gasoline and diesel. Due to the lower content of cyclic hydrocarbons in shale oil, hydrotreating it is also a superior choice for use as feedstock in ethylene cracking production.

[0003] Hydrotreating is a process in which petroleum products react with hydrogen under the action of a catalyst. The main hydrotreating reactions include three categories: low-temperature hydrotreating pretreatment, hydrorefining, and hydrocracking. Low-temperature hydrotreating pretreatment mainly involves the hydrogenation saturation of olefins and dienes; hydrorefining reactions mainly include desulfurization, denitrification, deoxygenation, aromatic saturation, and demetallization and removal of asphalt impurities; hydrocracking reactions mainly involve the reaction of large molecules with hydrogen to generate smaller molecules. The hydrotreating process typically involves heating the feedstock oil and hydrogen to the reaction temperature in a furnace, generally around 290-430°C. The mixture then enters the hydrotreating reactor, where the hydrogenation reaction takes place on a catalyst. The resulting hydrogenated products finally flow out of the reactor. Conventional hydrotreating processes are suitable for natural petroleum and feedstock oils with low olefin content. For oils containing olefins and dienes, a low-temperature hydrotreating pretreatment reactor is generally required.

[0004] CN114437798B discloses a shale oil hydrocracking method, which includes the following steps: (1) shale oil enters a hydropretreatment reactor for hydropretreatment reaction; (2) the material obtained in step (1) enters a hydrorefining reactor for hydrorefining reaction; (3) the material obtained in step (2) enters a hydrocracking reactor for hydrocracking reaction; (4) the hydrogen-rich gas obtained after gas-liquid separation of the reaction stream in step (3) is used as recycled hydrogen, and the liquid phase enters a fractionation tower for fractionation to obtain gas, naphtha, diesel oil and tail oil. This method can directly process full-fraction shale oil, adopts a one-pass process flow, and can produce high-quality diesel oil and lubricating oil base oil, but there is a problem of excessively high hydrocracking reaction temperature caused by high ammonia concentration.

[0005] Patent 200910012479.X discloses a single-stage series hydrocracking process for shale oil. Shale oil feedstock and hydrogen flow concurrently into the hydrorefining reactor from the top. Hydrorefining occurs in the presence of a hydrorefining catalyst. The effluent from the hydrorefining reaction enters the upper part of the hydrocracking reactor, where gas-liquid separation takes place. The gas phase exits from the top of the hydrocracking reactor, while the liquid phase, along with hydrogen entering from the bottom, flows countercurrently over the hydrocracking catalyst for hydrocracking. After the hydrocracking reaction, the liquid phase product exits from the bottom of the hydrocracking reactor, while the gas phase, along with the gas phase separated from the hydrorefining effluent, exits from the top of the hydrocracking reactor. Although this method can reduce the concentration of ammonia in contact with the hydrocracking catalyst, the hydrocracking reactor is difficult to operate, and shale oil that has not undergone low-temperature hydrotreating is highly prone to coking in the upper part of the hydrorefining reactor.

[0006] The above are all processes for producing high-quality diesel oil from shale oil, but the diesel produced has a high alkane content and generally a high pour point. In addition, the large amount of ammonia generated by shale oil makes it difficult for hydrocracking agents to exert their cracking activity. Summary of the Invention

[0007] The purpose of this disclosure is to provide a method and system for hydrocracking shale oil. The method of this disclosure can simultaneously produce high-quality ethylene cracking feedstock and low-pour-point diesel oil using shale oil as feedstock, while effectively avoiding the negative impact of ammonia adsorption on the cracking activity of the hydrocracking agent.

[0008] To achieve the above objectives, the first aspect of this disclosure provides a method for hydrocracking shale oil, the method comprising: S1. In the presence of the first hydrorefining catalyst, the shale oil is subjected to a hydrosaturation reaction in a hydropretreatment unit to obtain the first product; S2. In the presence of a second hydrorefining catalyst, the first product is subjected to a hydrorefining reaction in a hydrorefining apparatus to obtain a second product. S3. The second product is introduced into a separation device for separation. A portion of the separated diesel fraction and hydrogen are introduced into a hydrocracking unit to contact the catalyst for hydrocracking reaction. The hydrocracking reaction product is introduced into the separation device for separation. The catalyst in the hydrocracking unit includes a hydrocracking catalyst and a third hydrorefining catalyst; wherein the hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve, and the content of the ZSM-5 molecular sieve is 10-80% by weight based on the dry weight of the hydrocracking catalyst.

[0009] Optionally, in step S1, the conditions for the hydrogenation saturation reaction include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 150-260 °C, and a liquid hourly space velocity of 0.5-10 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500.

[0010] Optionally, in step S2, the conditions for the hydrogenation purification reaction include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 290-420 °C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500.

[0011] Optionally, in step S3, the conditions for the hydrocracking reaction include: a hydrogen partial pressure of 3.0-17.0 MPa, a reaction temperature of 280-420 °C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-2000.

[0012] Optionally, in step S1, the conditions for the hydrogenation saturation reaction include: a hydrogen partial pressure of 5-12 MPa, a reaction temperature of 160-210 °C, and a liquid hourly space velocity of 1.0-6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300-800; In step S2, the conditions for the hydrogenation purification reaction include: a hydrogen partial pressure of 5-12 MPa, a reaction temperature of 300-400 °C, and a liquid hourly space velocity of 0.5-2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 600-1200; In step S3, the conditions for the hydrocracking reaction include: a hydrogen partial pressure of 5.0-12.0 MPa, a reaction temperature of 290-380 °C, and a liquid hourly space velocity of 1.0-3.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800-1200.

[0013] Optionally, the reaction temperature of the hydrogenation refining reaction is 100-200°C higher than the reaction temperature of the hydrogenation saturation reaction.

[0014] Optionally, step S3 includes: drawing the remaining diesel fraction obtained from the separation device as product diesel; Based on the total weight of the shale oil introduced into the hydrotreating unit, the weight of the diesel oil as a product accounts for 10-90% of the total weight of the shale oil.

[0015] Optionally, the first hydrorefining catalyst, the second hydrorefining catalyst, and the third hydrorefining catalyst each independently contain a second support and an active component based on 15-55% by weight of metal oxides; The second carrier is selected from alumina and / or amorphous silica-alumina, and the active component is selected from one or more of Ni, Co, Mo and W.

[0016] Optionally, the hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve; the content of the ZSM-5 molecular sieve is 10-80% by weight based on the dry weight of the hydrocracking catalyst; the first support is selected from alumina and / or amorphous silica-alumina.

[0017] The second aspect of this disclosure provides a hydrocracking system used in the method provided in the first aspect of this disclosure, the system comprising: a hydropretreatment unit, a hydrorefining unit, a hydrocracking unit, and a separation unit; The outlet of the hydropretreatment unit is connected to the inlet of the hydrorefining unit, the outlet of the hydrorefining unit is connected to the inlet of the separation unit, the outlet of the hydrocracking unit is connected to the inlet of the separation unit, and the diesel outlet of the separation unit is connected to the inlet of the hydrocracking unit.

[0018] Through the above technical solution, the method disclosed herein can simultaneously produce high-quality ethylene cracking feedstock and low-pour-point diesel oil, while effectively avoiding the negative impact of ammonia adsorption on the cracking activity of hydrocracking agents.

[0019] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic flowchart of one specific implementation of the hydrocracking system disclosed herein.

[0021] Explanation of reference numerals in the attached figures Detailed Implementation

[0022] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0023] The first aspect of this disclosure provides a method for hydrocracking shale oil, the method comprising: S1, subjecting shale oil to a hydrosaturation reaction in a hydropretreatment unit in the presence of a first hydrorefining catalyst to obtain a first product; S2, subjecting the first product to a hydrorefining reaction in a hydrorefining unit in the presence of a second hydrorefining catalyst to obtain a second product; S3, introducing the second product into a separation unit for separation, introducing a portion of the separated diesel fraction and hydrogen into a hydrocracking unit to contact with a catalyst for a hydrocracking reaction, and introducing the hydrocracking reaction product into the separation unit for separation; wherein the catalyst in the hydrocracking unit includes a hydrocracking catalyst and a third hydrorefining catalyst; wherein the hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve, and the content of the ZSM-5 molecular sieve is 10-80% by weight, based on the dry weight of the hydrocracking catalyst.

[0024] The method disclosed herein first removes olefins and dienes in a hydrotreating pretreatment unit, reducing the coking and carbon deposition problems of olefins and dienes; simultaneously, it employs a parallel method of two-stage hydrotreating and hydrocracking reactions, and after removing ammonia through a separation unit, it reduces the negative impact of ammonia adsorption on the cracking activity of the hydrocracking catalyst; after the cracking reaction in the hydrocracking unit, the light distillate oil with high alkane content obtained can be used as a high-quality ethylene cracking feedstock, while the unconverted oil with a lower pour point after dewaxing can be used as a high-quality diesel component.

[0025] According to this disclosure, in step S3, the step of introducing the second product into the separation device for separation, and introducing a portion of the separated diesel fraction and hydrogen into the hydrocracking unit to contact the catalyst for hydrocracking reaction, and introducing the hydrocracking reaction product into the separation device for separation, means that the second product and the hydrocracking reaction product obtained from the hydrocracking unit are introduced into the separation device together for separation, a portion of the separated diesel is introduced into the hydrocracking unit together with hydrogen as hydrocracking feedstock to contact the catalyst for hydrocracking reaction, and the remaining diesel fraction obtained from the separation device is drawn out from the separation device as a product.

[0026] According to this disclosure, in step S1, the hydrogenation saturation reaction in the hydrogenation pretreatment unit is used to hydrogenate and saturate the olefins and dienes. In step S2, the hydrogenation refining reaction in the hydrogenation refining unit is used to hydrogenate and denitrify the reactants, hydrogenate and desulfurize them, and saturate them with aromatics.

[0027] According to this disclosure, the separation can be performed using methods well known to those skilled in the art, such as distillation or fractional distillation. This disclosure does not impose specific limitations on the separation conditions; the method can be selected based on the specific separation method, as long as it can separate the different components of the third product. In one embodiment, in step S3, the remaining diesel and naphtha fractions obtained are used as product diesel fraction and product naphtha fractionation devices, respectively.

[0028] In one specific embodiment of this disclosure, the conditions for the hydrogenation saturation reaction in step S1 include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 150-260°C, and a liquid hourly space velocity of 0.5-10 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500; preferably, the hydrogen partial pressure is 5-12 MPa, the reaction temperature is 160-210℃, and the liquid hourly space velocity is 1.0-6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300-800.

[0029] In one specific embodiment of this disclosure, the conditions for the hydrogenation purification reaction in step S2 include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 290-420°C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500; preferably, the hydrogen partial pressure is 5-12 MPa, the reaction temperature is 300-400℃, and the liquid hourly space velocity is 0.5-2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 600-1200.

[0030] In one specific embodiment of this disclosure, the conditions for the hydrocracking reaction in step S3 include: a hydrogen partial pressure of 3.0-17.0 MPa, a reaction temperature of 280-420°C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-2000; preferably, the hydrogen partial pressure is 5.0-12.0 MPa, the reaction temperature is 290-380℃, and the liquid hourly space velocity is 1.0-3.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800-1200.

[0031] In one specific embodiment of this disclosure, the negative impact of ammonia adsorption on the cracking activity of the hydrocracking catalyst can be further reduced, resulting in the production of higher-quality ethylene cracking feedstock and low-pour-point diesel.

[0032] According to this disclosure, the amount of diesel fraction introduced into the hydrocracking unit can vary within a wide range. In one specific embodiment of this disclosure, step S3 includes: drawing the remaining diesel fraction obtained from the separation unit as product diesel; based on the total weight of the shale oil introduced into the hydropretreatment unit, the weight of the product diesel accounts for 10-90% by weight of the total weight of the shale oil, preferably 20-80% by weight. The remaining diesel fraction refers to the portion remaining after removing the diesel fraction introduced into the hydrocracking unit from the diesel fraction obtained by the separation unit.

[0033] According to this disclosure, the fractions obtained by the separation device also include naphtha fractions. In one embodiment, the separated naphtha fractions and the remaining diesel fractions are respectively extracted as product naphtha and product diesel.

[0034] According to this disclosure, the first, second, and third hydrorefining catalysts may be the same or different. The hydrorefining catalysts may be those well known to those skilled in the art. In one specific embodiment, each of the first, second, and third hydrorefining catalysts independently contains a second support and an active component of 15-55% by weight, preferably 20-40% by weight, based on a metal oxide. The second support is selected from alumina and / or amorphous silica-alumina, and the active component is selected from one or more of Ni, Co, Mo, and W.

[0035] In one specific embodiment of this disclosure, the hydrotreating pretreatment unit and the hydrorefining unit are further provided with a hydrotreating protection catalyst, which is well known to those skilled in the art, such as RG-1, RG-30A, RG-30B, etc. In one embodiment, along the feed flow direction, a first hydrotreating protection catalyst and a first hydrorefining catalyst are sequentially arranged in the hydrotreating pretreatment unit, and the volume ratio of the first hydrotreating protection catalyst to the first hydrorefining catalyst can vary within a wide range, for example, it can be (0.01-0.2):1. In one embodiment, along the feed flow direction, a second hydrotreating protection catalyst and a second hydrorefining catalyst are sequentially arranged in the hydrorefining unit, and the volume ratio of the second hydrotreating protection catalyst to the second hydrorefining catalyst can vary within a wide range, for example, it can be (0.02-0.3):1.

[0036] In one embodiment of this disclosure, a hydrocracking unit is also provided with a hydroprotection catalyst. In one embodiment, along the feed flow direction, a third hydroprotection catalyst, a hydrocracking catalyst, and a third hydrorefining catalyst are sequentially provided in the hydrocracking unit. The volume ratio of the third hydroprotection catalyst, the hydrocracking catalyst, and the third hydrorefining catalyst can vary within a large range, for example, it can be (0.01-0.1):1:(0.05-0.2).

[0037] According to this disclosure, hydrocracking catalysts are well known to those skilled in the art. In one specific embodiment of this disclosure, the hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve. The content of the ZSM-5 molecular sieve is 10-80% by weight, based on the dry weight of the hydrocracking catalyst. The second support is selected from alumina and / or amorphous silica-alumina.

[0038] like Figure 1 As shown, a second aspect of this disclosure provides a hydrocracking system used in the method provided in the first aspect of this disclosure. The system includes: a hydropretreatment unit I, a hydrorefining unit II, a hydrocracking unit III, and a separation unit IV; the outlet of the hydropretreatment unit I is connected to the inlet of the hydrorefining unit II, the outlet of the hydrorefining unit II is connected to the inlet of the separation unit IV, the outlet of the hydrocracking unit III is connected to the inlet of the separation unit IV, and the diesel outlet of the separation unit IV is connected to the inlet of the hydrocracking unit III.

[0039] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0040] All catalysts used were produced by the Changling Branch of China Petroleum & Chemical Corporation Catalyst Co., Ltd. The feedstock used was shale oil, the composition of which is shown in Table 1.

[0041] Example 1 In such Figure 1 The system shown undergoes shale oil hydrocracking, and the specific method is as follows: S1, shale oil 1 and hydrogen 2 are mixed and first enter the hydrogenation pretreatment unit I for hydrogenation saturation reaction of olefins and dienes to obtain the first product 3; S2. The first product 3 is fed into the hydrorefining unit II for hydrorefining reactions of aromatics and aromatic rings containing nitrogen and sulfur heteroatoms, including hydrosaturation, hydrodenitrogenation and hydrosulfurization, to obtain hydrorefined shale oil, i.e., the second product 4, whose properties are shown in Table 1. S3. The second product 4 is mixed with the third product 5 of the hydrocracking unit III. The mixture 6 is introduced into the separation unit IV, which mainly performs gas-liquid phase separation, removal of ammonia and hydrogen sulfide, and fractionation of liquid phase products. Gas phase product 7, naphtha fraction 8, and diesel fraction 9 can be obtained. Part of the diesel fraction 10 is recycled to the inlet of the hydrocracking unit III and mixed with hydrogen 11 to enter the hydrocracking unit III for hydrocracking reaction, mainly the cracking reaction of straight-chain hydrocarbons, to form the third product 5.

[0042] The catalyst loading in the hydrotreating pretreatment unit is as follows: from top to bottom, it consists of RG-1 hydrotreating protectant and RN-410B hydrorefining catalyst; the catalyst loading volumes are 5 mL and 30 mL respectively.

[0043] The catalyst loading in the hydrorefining unit is as follows: from top to bottom, it consists of RG-1 hydroprotectant and RN-410B hydrorefining catalyst; the catalyst loading volumes are 15 mL and 150 mL respectively.

[0044] The catalyst loading in the hydrocracking unit is as follows: from top to bottom, RG-1 hydroprotectant, RDW-1 hydrocracking catalyst, and RN-410B hydrorefining catalyst; the catalyst loading volumes are 10 mL, 150 mL, and 15 mL, respectively. The RDW-1 hydrocracking catalyst contains 30-60% by weight of ZSM-5 molecular sieve.

[0045] The reaction conditions are shown in Table 2, and the conversion rate and product distribution are shown in Table 3, and so on.

[0046] Comparative Example 1 Shale oil hydrocracking was performed using the same method as in Example 1, except for the catalyst loading method. Specifically, the catalyst loading in the hydrocracking unit was as follows: from top to bottom, RG-1 hydroprotectant, RIC-3 hydrocracking catalyst, and RN-410B hydrorefining catalyst; the catalyst loading volumes were 10 mL, 150 mL, and 15 mL, respectively. The RIC-3 hydrocracking catalyst contained 30-60% by weight of Y molecular sieve.

[0047] Comparative Example 2 In this comparative example, the catalyst loading in the hydropretreatment unit, hydrorefining unit, and hydrocracking unit is the same as in Example 1. The difference lies in the process flow, which is as follows: (1) Shale oil enters the hydrotreating pretreatment reactor for hydrotreating reaction; (2) The material obtained in step (1) enters the hydrorefining reactor for hydrorefining reaction; (3) The material obtained in step (2) enters the hydrocracking reactor for hydrocracking reaction; (4) After separation and fractionation of the reaction stream in step (3), gaseous products, naphtha and diesel are obtained.

[0048]

[0049]

[0050] Note: In the table, shale oil 1, diesel fraction 9, and diesel fraction 10 are listed in the appendix. Figure 1 The description is consistent with the previous one; the extraction amount of diesel fraction 9 is the weight percentage of the weight of diesel drawn from the separation unit as product to the total weight of shale oil introduced into the hydrotreating pretreatment unit.

[0051]

[0052] Table 1 shows that after hydrotreating and hydrorefining, the S and N contents of the hydrotreated shale oil are 182 ppm and 18 ppm, respectively. This indicates that the hydrotreated shale oil obtained using the method disclosed in this paper has a low nitrogen content and can ultimately be used as circulating oil in the hydrocracking unit after separation. The nitrogen content of the circulating oil meets the feed requirements of the hydrocracking unit, effectively avoiding catalyst deactivation in the hydrocracking unit.

[0053] As shown in Tables 2 and 3, the products obtained from hydrocracking in the hydrocracking unit of Example 1, after separation, yield naphtha and diesel oil with superior properties. The naphtha contains 96.6% alkanes, making it suitable as a high-quality feedstock for ethylene cracking. Compared to the hydrocracking shale oil in Table 1, the diesel oil has a lower alkanes content and a pour point of -5°C (below 0°C), thus it can be used as a component of China VI clean diesel fuel.

[0054] Compared to Example 1, Comparative Example 1 uses a hydrocracking catalyst containing a Y-type molecular sieve in its hydrocracking reaction zone, resulting in a higher selectivity for cyclic hydrocarbon conversion than for alkanes. Consequently, the alkanes content in the resulting diesel product is higher than that in hydrotreated shale oil, leading to a pour point greater than 0°C, making it unsuitable as a component of China VI clean diesel. Furthermore, the alkanes content in the naphtha fraction of Comparative Example 1 is significantly lower than that in the naphtha fraction of Example 1, making it a less suitable feedstock for ethylene cracking.

[0055] Compared to Example 1, the naphtha and diesel yields in Comparative Example 2 were essentially the same as those in Example 1, and the properties of the naphtha and diesel products in Comparative Example 2 were also essentially the same as those in Example 1. However, in Comparative Example 2, the hydrocracking unit was directly connected in series with the hydrorefining unit, resulting in a higher concentration of ammonia entering the hydrocracking unit. Therefore, compared to Example 1, the hydrocracking reaction temperature in Comparative Example 2 was nearly 50°C higher than that in Example 1, which is detrimental to the long-term operation of the catalyst.

[0056] Therefore, by subjecting shale oil to two-stage hydrotreating and connecting the hydrorefining reaction and the hydrocracking reaction in parallel, this disclosure enables the simultaneous production of high-quality ethylene cracking feedstock and low-pour-point diesel oil, while effectively avoiding the negative impact of ammonia adsorption on the cracking activity of the hydrocracking agent.

[0057] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0058] 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, this disclosure will not describe the various possible combinations separately.

[0059] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for hydrocracking shale oil, the method comprising: S1. In the presence of the first hydrorefining catalyst, the shale oil is subjected to a hydrosaturation reaction in a hydropretreatment unit to obtain the first product; S2. In the presence of a second hydrorefining catalyst, the first product is subjected to a hydrorefining reaction in a hydrorefining apparatus to obtain a second product. S3. The second product is introduced into a separation device for separation. A portion of the separated diesel fraction and hydrogen are introduced into a hydrocracking unit to contact the catalyst for hydrocracking reaction. The hydrocracking reaction product is introduced into the separation device for separation. The catalyst in the hydrocracking unit includes a hydrocracking catalyst and a third hydrorefining catalyst; wherein the hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve, and the content of the ZSM-5 molecular sieve is 10-80% by weight based on the dry weight of the hydrocracking catalyst.

2. The method according to claim 1, wherein, In step S1, the conditions for the hydrogenation saturation reaction include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 150-260 °C, and a liquid hourly space velocity of 0.5-10 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500.

3. The method according to claim 1, wherein, In step S2, the conditions for the hydrogenation purification reaction include: a hydrogen partial pressure of 3-17 MPa, a reaction temperature of 290-420 °C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500.

4. The method according to claim 1, wherein, In step S3, the conditions for the hydrocracking reaction include: a hydrogen partial pressure of 3.0-17.0 MPa, a reaction temperature of 280-420 °C, and a liquid hourly space velocity of 0.3-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-2000.

5. The method according to claim 1, wherein, In step S1, the conditions for the hydrogenation saturation reaction include: a hydrogen partial pressure of 5-12 MPa, a reaction temperature of 160-210 °C, and a liquid hourly space velocity of 1.0-6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300-800; In step S2, the conditions for the hydrogenation purification reaction include: a hydrogen partial pressure of 5-12 MPa, a reaction temperature of 300-400 °C, and a liquid hourly space velocity of 0.5-2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 600-1200; In step S3, the conditions for the hydrocracking reaction include: a hydrogen partial pressure of 5.0-12.0 MPa, a reaction temperature of 290-380 °C, and a liquid hourly space velocity of 1.0-3.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800-1200.

6. The method according to claim 1, wherein, The reaction temperature of the hydrogenation refining reaction is 100-200°C higher than that of the hydrogenation saturation reaction.

7. The method according to claim 1, wherein, Step S3 includes: drawing the remaining diesel fraction obtained from the separation device as product diesel; Based on the total weight of the shale oil introduced into the hydrotreating unit, the weight of the diesel oil as a product accounts for 10-90% of the total weight of the shale oil.

8. The method according to claim 1, wherein, The first hydrorefining catalyst, the second hydrorefining catalyst, and the third hydrorefining catalyst each independently contain a second support and an active component based on 15-55% by weight of metal oxides; The second carrier is selected from alumina and / or amorphous silica-alumina, and the active component is selected from one or more of Ni, Co, Mo and W.

9. The method according to claim 1, wherein, The hydrocracking catalyst contains a first support and a ZSM-5 molecular sieve; based on the dry weight of the hydrocracking catalyst, the content of the ZSM-5 molecular sieve is 2-50% by weight; the first support is selected from alumina and / or amorphous silica-alumina.

10. A hydrocracking system used in the method of any one of claims 1-9, the system comprising: Hydrotreating unit (I), hydrorefining unit (II), hydrocracking unit (III) and separation unit (IV); The outlet of the hydropretreatment unit (I) is connected to the inlet of the hydrorefining unit (II), the outlet of the hydrorefining unit (II) is connected to the inlet of the separation unit (IV), the outlet of the hydrocracking unit (III) is connected to the inlet of the separation unit (IV), and the diesel outlet of the separation unit (IV) is connected to the inlet of the hydrocracking unit (III).

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