A method for converting light naphtha

Abstract

The application discloses a conversion method of light naphtha. The method comprises the following steps: (1) mixing light naphtha, optionally added olefins and hydrogen through a hydroconversion reaction zone, and controlling the olefin content in the total feed of the light naphtha and the optionally added olefins to be 1% to 8% of the total feed weight; the hydroconversion reaction zone is filled with a hydroconversion catalyst containing ZSM-5 molecular sieve; (2) the hydroconversion reaction effluent of step (1) enters a high-pressure separator, the obtained hydrogen-rich gas is used as circulating hydrogen, and the liquid phase effluent enters a separation system to obtain ethane, propane and n-butane. The method can increase the proportion of C2-C4 normal alkanes in the hydrogenation product, and reduce the content of by-product methane.

Description

Technical Field

[0001] This invention belongs to the field of hydrocarbon oil hydroconversion, specifically relating to a hydroconversion method for producing high-quality ethylene feedstock from light naphtha. Background Technology

[0002] In petroleum processing, especially in the upgrading of heavy oil using molecular sieve catalysts, light naphtha components are inevitably generated. These light naphtha components have a high content of isoalkanes. Although they have a high octane number when used as gasoline blending components, with the decline in gasoline consumption and the influence of saturated vapor pressure, more and more light naphtha components cannot be effectively utilized. This portion of light naphtha is usually used as a feedstock for ethylene, but due to its molecular structure, the yield of ethylene and trienes is low during steam cracking, significantly reducing the economic efficiency of ethylene plants.

[0003] CN115612524A discloses a method for increasing the concentration of n-chain alkanes in a light naphtha feed stream. The method includes separating the naphtha feed stream into a stream rich in n-chain alkanes and a stream rich in non-n-chain alkanes. An isomerization feed stream is obtained from the non-n-chain alkanes stream and isomerized on an isomerization catalyst to convert the non-n-chain alkanes into n-chain alkanes and generate an isomerized effluent. Optionally, the isomerized effluent can be separated into a propane stream and a C4 stream in a single column. + Hydrocarbon feedstock. C4 + The hydrocarbon feed stream can be recycled to the step of separating the naphtha feed stream.

[0004] CN116023214A discloses a method and system for producing n-alkanes. The method involves contacting isobutane feedstock with an isobutane conversion catalyst in an isobutane conversion unit to carry out an isobutane conversion reaction. The isobutane conversion catalyst has high catalytic activity, is chlorine-free, safe and non-toxic, and reduces corrosion and wear on equipment. The resulting reaction product containing n-alkanes is introduced into a membrane separation unit for membrane separation treatment. The membrane separation element, including a molecular sieve membrane, enables efficient separation of n-alkanes and isoalkanes. The separation efficiency is high and the method is simple and easy to implement.

[0005] The above methods can all convert small molecule isoalkanes into n-alkanes, but the energy required for the conversion of hydrocarbons with different molecular structures is different, and it is difficult to effectively guarantee the yield of the target product by using a single conversion process. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide a method for converting light naphtha. This method uses light naphtha as raw material and can effectively convert isoparaffins in light naphtha into small molecule C2-C4 n-paraffins, thereby improving the quality of ethylene feedstock.

[0007] This invention provides a method for converting naphtha, the method comprising:

[0008] (1) Light naphtha, optionally additional olefins, and hydrogen are mixed and passed through the hydroconversion reaction zone, and the olefin content in the total feed of light naphtha and optionally additional olefins is controlled to be 1% to 8% of the total feed weight, preferably 3% to 6%, wherein the olefin content refers to the total content of butene, pentene, and hexene; the hydroconversion reaction zone is filled with a hydroconversion catalyst containing ZSM-5 molecular sieves;

[0009] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator, and the hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent enters the separation system to separate ethane, propane and n-butane.

[0010] According to the present invention, the optionally added olefin refers to the olefin content in the reaction system, which is selected based on the required olefin content in the total feed, and may or may not require the addition of olefins. The additional olefins preferably include at least one of butene, pentene, and hexene. The present invention does not impose any particular limitation on the respective proportions of butene, pentene, and hexene in the additional olefins.

[0011] According to the present invention, when the olefin content in light naphtha does not meet the requirement for the total olefin content in the feed, it is necessary to introduce additional olefins from an external source. Further, the additional olefins preferably include at least one of butene, pentene, and hexene.

[0012] According to the method of the present invention, the n-butane obtained in step (2) can be n-butane-rich, wherein the mass content of n-butane in the n-butane-rich is 95%-100%. Further, step (2) separates ethane and propane, C4... + The above fractions; C4 + The above fractions are further separated to obtain n-butane-rich and isobutane-rich fractions. The n-butane-rich fraction is directly used as a feedstock for ethylene production by steam cracking, while the isobutane-rich fraction is recycled to the inlet of the hydroconversion reaction zone for further recycling and cracking.

[0013] According to the present invention, the light naphtha is derived from one or more fractions obtained by processes such as hydrocracking, catalytic cracking or coking.

[0014] According to the present invention, the initial boiling point of the light naphtha is 10°C to 30°C, preferably 15°C to 25°C; and the final boiling point is 50°C to 100°C, preferably 55°C to 70°C.

[0015] According to the present invention, the content of C5-C6 isoalkanes in the hydrocracked light naphtha is 60wt% to 90wt%, preferably 70wt% to 80wt%; C 7+The hydrocarbon content is 0-10 wt%, preferably 0.5 wt%-5 wt%; the C5-C6 n-alkanes content is 10 wt%-30 wt%, preferably 15 wt%-25 wt%; the C4 hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; the cyclic hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; and the total weight of the hydrocracked light naphtha is 100 wt%. When the light naphtha is hydrocracked light naphtha, olefins need to be introduced from the outside, so that the olefin content in the total feed of light naphtha and the added olefins is 1%-8% of the total feed weight, preferably 3%-6%, where the olefin content refers to the total content of butene, pentene, and hexene.

[0016] According to the present invention, a fixed-bed reactor is used for the hydrogenation conversion reaction.

[0017] According to the present invention, preferably, the hydroconversion reaction zone is filled with at least two hydroconversion catalyst beds, and more preferably, the hydroconversion reaction zone is filled with 2 to 3 hydroconversion catalyst beds. Further, the active metal content of the hydroconversion catalyst decreases sequentially along the flow direction, wherein the active metal content of the hydroconversion catalyst in adjacent catalyst beds differs by 1 to 25 percentage points (based on oxides), preferably by 5 to 15 percentage points. Preferably, in the hydroconversion catalysts in adjacent catalyst beds, the content of Group VIB metals differs by 1 to 23 percentage points (preferably by 3 to 15 percentage points) and the content of Group VIII non-precious metals differs by 0 to 4 percentage points (based on oxides). Further, along the flow direction, the ratio of the upstream catalyst loading volume to the downstream catalyst loading volume in adjacent catalyst beds is 1:3 to 3:1, preferably 1:2 to 2:1.

[0018] According to the present invention, the hydroconversion catalyst comprises a ZSM-5 molecular sieve, an active metal component, and a binder. Further, the ZSM-5 molecular sieve has a SiO2 / Al2O3 molar ratio of 10–50 and a specific surface area of ​​300–500 m². 2 / g, with a pore volume of 0.2–0.4 mL / g. Further, in the hydroconversion catalyst, based on the weight of the catalyst, the content of the ZSM-5 molecular sieve is 30 wt%–80 wt%, preferably 40 wt%–70 wt%.

[0019] According to the present invention, the binder is preferably alumina. Further, in the hydroconversion catalyst, the binder content, calculated as oxide, is 5 wt% to 65 wt%, preferably 10 wt% to 35 wt%, based on the weight of the catalyst.

[0020] According to the present invention, the active metal component is selected from one or more of Group VIB metals and Group VIII non-noble metals of the periodic table. The Group VIB metals are preferably selected from one or more of molybdenum and tungsten, and the Group VIII non-noble metals are preferably selected from one or more of cobalt and nickel. Further, in the hydroconversion catalyst, based on the weight of the catalyst, the content of the Group VIB metals (calculated as oxides) is 5 wt% to 30 wt%, preferably 10 wt% to 20 wt%; and the content of the Group VIII non-noble metals (calculated as oxides) is 0.5 wt% to 15 wt%, preferably 3 wt% to 10 wt%.

[0021] According to the present invention, the specific surface area of ​​the hydroconversion catalyst is 200-400 m². 2 / g, with a pore volume of 0.20~0.40mL / g.

[0022] According to the present invention, the preparation method of the hydroconversion catalyst can be carried out according to conventional methods in the art. The preparation method includes the preparation of a support and the loading of an active metal component, wherein the preparation process of the support is as follows: a shape-selective cracking molecular sieve and a binder are mechanically mixed, shaped, and then dried and calcined to form a catalyst support. The drying and calcination of the support can be carried out under conventional conditions. The drying conditions are: drying at 100℃~150℃ for 1~12 hours. The calcination conditions are: calcination at 450℃~550℃ for 2.5~6.0 hours.

[0023] According to the present invention, in the preparation method of the hydroconversion catalyst, the method of loading the active metal component is a conventional method, such as kneading, impregnation, etc., with impregnation being preferred. The impregnation method can be a saturated impregnation method, an excess impregnation method, or a complex impregnation method, that is, impregnating the catalyst support with a solution containing the desired active metal component, followed by drying and calcination to obtain the hydroconversion catalyst. The drying conditions are: drying at 100℃~150℃ for 1~12 hours. The calcination conditions are: calcination at 450℃~550℃ for 2.5~6.0 hours.

[0024] According to the present invention, the hydroconversion reaction conditions are as follows: reaction pressure is 0.5 MPa to 10.0 MPa, preferably 2.0 MPa to 5.0 MPa; reaction temperature is 250°C to 500°C, preferably 350°C to 450°C; and liquid hourly space velocity is 0.1 h⁻¹. -1 ~15.0h -1 0.5h is preferred -1 ~5.0h -1 The hydrogen-to-oil volume ratio is 10:1 to 2500:1, preferably 100:1 to 2000:1, and even more preferably 100:1 to 1000:1.

[0025] According to the present invention, the hydroconversion products (ethane, propane, and n-butane-rich products) are fed into a steam cracking unit to produce ethylene, yielding the main target products ethylene, propylene, and butadiene, wherein the yields of these trienes are the mass percentages of the ethylene, propylene, and butadiene production relative to the hydroconversion product feed. The steam cracking ethylene production operating conditions are: reaction temperature 860–890°C, reaction pressure 0.1–0.3 MPa, and water-to-oil mass ratio 0.2–0.6.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] (1) In the hydroconversion process, the first step is the dehydrogenation reaction. The inventors have discovered that isoalkanes with smaller molecular weights are more difficult to dehydrogenate. Therefore, accelerating the dehydrogenation process is a key step in achieving efficient conversion of isoalkanes in light naphtha. The conversion method of this invention can promote the dehydrogenation reaction of isoalkanes by controlling the olefin content in the total feed, thereby increasing the reaction rate. Furthermore, the reaction activity of the hydroconversion catalyst is mainly affected by the hydroconversion performance, while the reaction process of isoalkanes is mainly affected by the acidic centers, i.e., the molecular sieve. Further research by the inventors has found that ZSM-5 molecular sieves with higher strong acid content are more prone to cracking reactions during the hydroconversion process, and can selectively convert isoalkanes in light naphtha into ethane, propane, and n-butane, increasing the proportion of C2-C4 n-alkanes in the hydroconversion products while reducing the content of the byproduct methane. Preferably, the method of the present invention can significantly increase the yield of small molecule n-alkanes in the product by loading a hydrogenation conversion catalyst bed with different active metal contents, and gradually decreasing the active metal content along the flow direction, and by matching the dehydrogenation performance of the catalyst.

[0028] (2) The hydroconversion method of the present invention promotes the dehydrogenation reaction of isoparaffins by controlling the olefin content in the total feed, thereby increasing the reaction rate; at the same time, the hydroconversion reaction zone is filled with ZSM-5 molecular sieve catalyst with a high strong acid content. The synergistic effect of the two greatly increases the content of small molecule n-paraffins in the hydrogenation products and reduces the amount of methane generated, thereby increasing the ethylene yield and total yield of trienes in the ethylene unit. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention;

[0030] Explanation of key figure labels:

[0031] 1-Hydrocracking light naphtha, 12-Additional olefins, 2-Hydrogen, 3-Hydroconversion reaction zone, 4-Hydroconversion reaction zone effluent, 5-High-pressure separator, 6-Hydrogen-rich gas stream, 7-Liquid stream from high-pressure separator, 8-Separation system, 9-Ethane and propane, 10-Isobutane, 11-n-Butane. Detailed Implementation

[0032] The following examples further illustrate the function and effect of the present invention, but the following examples do not constitute a limitation on the method of the present invention.

[0033] Unless otherwise specified, all percentages in this invention refer to mass fractions.

[0034] In the examples and comparative examples, the total volumetric space velocity is the ratio of the fresh feed volume to the total catalyst volume.

[0035] The method of the present invention, such as Figure 1 As shown, the process includes: hydrocracking light naphtha 1, additionally added olefins 12, and hydrogen 2 mixed and fed into the hydroconversion reaction zone 3 for hydroconversion reaction; the hydroconversion reaction effluent 4 enters the separator 5; the separated gaseous stream 6 rich in hydrogen is recycled; the liquid stream 7 enters the separation system 8; and the separated 9 ethane, propane, and C4... + Of the above fractions, ethane and propane 9 are used directly as ethylene feedstock, C4 + The above fractions were separated to obtain n-butane 11 as ethylene feedstock, and isobutane 10 was recycled to the inlet of hydrogenation conversion reaction zone 3.

[0036] In this invention, the hydroconversion catalysts in each example are designated as Cat-A followed by a number, such as Cat-A1, Cat-A2, Cat-A3, and Cat-A4. The hydroconversion catalysts were prepared using a conventional active metal saturation impregnation method, and the physicochemical properties of the obtained catalysts are shown in Table 1.

[0037] The main properties of the cracked light naphtha used in each example of this invention are shown in Table 3.

[0038] In this invention, the yield of n-alkane = n-alkane yield in hydrogenation conversion products / fresh feed amount × 100%, by mass.

[0039] In this invention, methane yield = methane yield in hydrogenation conversion products / fresh feed amount × 100%, by mass.

[0040] In this invention, the fresh feedstock in each example includes hydrocracked light naphtha and additionally introduced olefins.

[0041] In this invention, the olefins additionally introduced into each example of hydrocracking light naphtha are a mixture of butene, pentene, and hexene.

[0042] In this invention, in the various hydroconversion reaction conditions, the hydrogen-to-oil volume ratio refers to the ratio of the total volume of hydrogen to the total feed, namely hydrocracking light naphtha and the additionally introduced olefins.

[0043] In this invention, in each example, the olefin content refers to the total content of butene, pentene, and hexene.

[0044] In this invention, the n-alkanes in Tables 3-4 include ethane, propane, and n-butane.

[0045] In this invention, the n-butane content of the isolated n-butane is above 96%.

[0046] Example 1

[0047] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0048] (1) Hydrocracking light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone. The hydroconversion reaction zone is filled with hydroconversion catalyst Cat-A1; the olefin content in the total feed is controlled to be 3%.

[0049] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0050] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0051] Example 2

[0052] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0053] (1) Hydrocracking of light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone for hydroconversion reaction. The hydroconversion reaction zone is filled with hydroconversion catalyst Cat-A2; the olefin content in the total feed is controlled to be 4%.

[0054] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0055] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0056] Example 3

[0057] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0058] (1) Hydrocracking light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone for hydroconversion reaction. The hydroconversion reaction zone is filled with hydroconversion catalyst Cat-A3; the olefin content in the total feed is controlled to be 5%.

[0059] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0060] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0061] Example 4

[0062] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0063] (1) Hydrocracking light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone for hydroconversion reaction. The hydroconversion reaction zone is filled with hydroconversion catalyst Cat-A4; the olefin content in the total feed is controlled to be 6%.

[0064] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0065] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0066] Example 5

[0067] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0068] (1) Hydrocracking light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone. The hydroconversion reaction zone is filled with hydroconversion catalysts Cat-A1 and Cat-A2; the olefin content in the total feed is controlled to be 3%.

[0069] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0070] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0071] Example 6

[0072] The conversion method of hydrocracking light naphtha adopts, for example... Figure 1 The process is shown below. The method specifically includes:

[0073] (1) Hydrocracking light naphtha, additionally introduced olefins and hydrogen are mixed and carried out in the hydroconversion reaction zone. The hydroconversion reaction zone is filled with hydroconversion catalysts Cat-A1, Cat-A3 and Cat-A5; the olefin content in the total feed is controlled to be 3%.

[0074] (2) The hydrogen-rich gas obtained from the hydrogenation reaction effluent of step (1) is used as recycled hydrogen after gas-liquid separation. The liquid effluent is separated to obtain ethane, propane, and n-butane as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation reaction zone for recycling and cracking.

[0075] The process conditions and hydrogenation effect in this example are shown in Table 3.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that no olefins are added to the light naphtha feedstock, that is, the olefin content in the total feedstock is 0.

[0078] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that the olefin content in the total feed is controlled at 10%.

[0081] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0082] Comparative Example 3

[0083] The difference from Example 5 is that the hydroconversion reaction zone is filled with hydroconversion catalysts Cat-A5 and Cat-A1.

[0084] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0085] Table 1. Composition and physicochemical properties of hydroconversion catalysts

[0086]

[0087]

[0088] Table 2. Main Properties of Hydrocracked Light Naphtha

[0089] raw material Hydrocracking light naphtha <![CDATA[C4 isoparaffin content, wt%]]> 1 <![CDATA[Content of n-C4 paraffin, wt%]]> 2 <![CDATA[Content of C5-C6 normal paraffin, wt%]]> 16 <![CDATA[C5-C6 isoparaffin content, wt%]]> 78 <![CDATA[C 7+ Hydrocarbon and cyclic hydrocarbon content, wt% 3 Initial boiling point, ℃ 24 Final boiling point, ℃ 64

[0090] Table 3. Process conditions and conversion results of each embodiment.

[0091]

[0092] Table 3 continues with the process conditions and conversion results of each embodiment.

[0093]

[0094]

[0095] Table 4. Process conditions and conversion results for each comparative example.

[0096]

[0097] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for converting naphtha, the method comprising: (1) Light naphtha, optionally additional olefins, and hydrogen are mixed and passed through the hydroconversion reaction zone, and the olefin content in the total feed of light naphtha and optionally additional olefins is controlled to be 1% to 8% of the total feed weight, preferably 3% to 6%, wherein the olefin content refers to the total content of butene, pentene, and hexene; the hydroconversion reaction zone is filled with a hydroconversion catalyst containing ZSM-5 molecular sieves; (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator, and the hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent enters the separation system to separate ethane, propane and n-butane.

2. The method according to claim 1, characterized in that: The additional olefins include at least one of butene, pentene, and hexene.

3. The method according to claim 1, characterized in that: The light naphtha is derived from one or more fractions obtained through hydrocracking, catalytic cracking, or coking processes. Preferably, the initial boiling point of the light naphtha is 10℃~30℃, more preferably 15℃~25℃; and the final boiling point is 50℃~100℃, more preferably 55℃~70℃.

4. The method according to any one of claims 1-3, characterized in that: The light naphtha is hydrocracked light naphtha, and the content of C5-C6 isoalkanes in the hydrocracked light naphtha is 60wt% to 90wt%, preferably 70wt% to 80wt%; C 7+ The hydrocarbon content is 0-10 wt%, preferably 0.5 wt%-5 wt%; the C5-C6 n-alkanes content is 10 wt%-30 wt%, preferably 15 wt%-25 wt%; the C4 hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; the cyclic hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; and the total weight of the hydrocracked light naphtha is 100 wt%.

5. The method according to claim 1, characterized in that: The hydroconversion reaction zone is filled with a hydroconversion catalyst. Preferably, the hydroconversion reaction zone is filled with at least two hydroconversion catalyst beds. More preferably, the hydroconversion reaction zone is filled with 2 to 3 hydroconversion catalyst beds. Preferably, along the flow direction, the ratio of the upstream catalyst loading volume to the downstream catalyst loading volume in two adjacent catalyst beds is 1:3 to 3:1, more preferably 1:2 to 2:

1.

6. The method according to claim 1, characterized in that: The hydroconversion catalyst comprises ZSM-5 molecular sieve, active metal component and binder; The ZSM-5 molecular sieve has a SiO2 / Al2O3 molar ratio of 10–50 and a specific surface area of ​​300–500 m². 2 / g, pore volume is 0.2~0.4mL / g; The active metal component is selected from one or more of Group VIB metals and Group VIII non-precious metals in the periodic table. The Group VIB metals are preferably selected from one or more of molybdenum and tungsten, and the Group VIII non-precious metals are preferably selected from one or more of cobalt and nickel. The binder is preferably alumina.

7. The method according to claim 1, characterized in that: In the hydroconversion catalyst, based on the weight of the catalyst, the content of the mordenite molecular sieve is 30wt% to 80wt%, preferably 40wt% to 70wt%; the content of the Group VIB metal as oxide is 5wt% to 30wt%, preferably 10wt% to 20wt%; the content of the Group VIII non-precious metal as oxide is 0.5wt% to 15wt%, preferably 3wt% to 10wt%; and the content of the binder as oxide is 5wt% to 65wt%, preferably 10wt% to 35wt%.

8. The method according to claim 5, 6 or 7, characterized in that: The active metal content of the hydroconversion catalyst decreases sequentially along the flow direction. The active metal content of the hydroconversion catalyst packed in two adjacent catalyst beds differs by 1 to 25 percentage points in terms of oxides, preferably by 5 to 15 percentage points. Preferably, the content of Group VIB metals as oxides in the hydroconversion catalysts packed in two adjacent catalyst beds differs by 1 to 23 percentage points, more preferably by 3 to 15 percentage points, and the content of Group VIII non-precious metals as oxides differs by 0 to 4 percentage points.

9. The method according to claim 1, characterized in that: The specific surface area of ​​the hydroconversion catalyst is 200–400 m². 2 / g, with a pore volume of 0.20~0.40mL / g.

10. The method according to claim 1, characterized in that: The hydrogenation conversion reaction conditions are as follows: reaction pressure of 0.5 MPa to 10.0 MPa, reaction temperature of 250°C to 500°C, and liquid hourly space velocity of 0.1 h⁻¹. -1 ~15.0h -1 The hydrogen-to-oil volume ratio is 10:1 to 2500:1; Preferably, the hydrogenation conversion reaction conditions are as follows: reaction pressure of 2.0 MPa to 5.0 MPa, reaction temperature of 350°C to 450°C, and liquid hourly space velocity of 0.5 h⁻¹. -1 ~5.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:1, preferably 100:1 to 1000:1.

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