A hydroconversion process for sulfur-containing naphthas

Abstract

The application discloses a hydroconversion method of sulfur-containing naphtha. The method comprises the following steps: mixing the sulfur-containing naphtha with hydrogen and performing hydroconversion reaction through a hydroconversion reaction zone; the reaction effluent enters a separation system to obtain hydrogen-rich gas and a hydroconversion product through separation; the hydroconversion reaction zone is sequentially filled with a hydroconversion catalyst I and a hydroconversion catalyst II along the flow direction; and the volume ratio of the hydroconversion catalyst I to the hydroconversion catalyst II is 1:3-3:1. The method can effectively convert isomeric alkanes in the naphtha into normal alkanes, improve the ethylene raw material quality, and solve the problem of sulfur injection in the ethylene production device.

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 sulfur-containing naphtha. Background Technology

[0002] Hydrocracking technology is characterized by its strong adaptability to feedstocks, high flexibility in production operations and product formulations, and high product quality. It can directly convert various heavy and low-quality feedstocks into high-quality jet fuel, diesel oil, lubricating oil base materials, and feedstocks for ethylene production from naphtha and tail oil steam cracking, which are in high demand in the market. It has become one of the most important deep hydrocarbon processing technologies in modern refining and petrochemical industries. The ethylene industry is the core of the petrochemical industry and one of the important indicators for measuring a country's petrochemical development level.

[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 methods described above can all convert small-molecule isoalkanes into n-alkanes, but the energy required for conversion varies depending on the molecular structure of the hydrocarbon. Using a single conversion process is insufficient to effectively guarantee the yield of the target product. Furthermore, ethylene feedstock obtained through hydrogenation processes undergoes a process where organic sulfur is removed and converted into hydrogen sulfide during the hydrogenation reaction, and this hydrogen sulfide is then removed during product separation. Therefore, the sulfur content in ethylene feedstock is typically low, and sulfur injection is necessary before it enters the ethylene cracking furnace to prevent coking of the furnace tubes. 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 the hydroconversion of sulfur-containing naphtha. This method uses sulfur-containing naphtha as raw material and can effectively convert isoparaffins in naphtha into n-paraffins, thereby improving the quality of ethylene feedstock.

[0007] This invention provides a method for the hydroconversion of sulfur-containing naphtha, the method comprising:

[0008] Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction. The reaction effluent enters a separation system to separate hydrogen-rich gas and hydroconversion products. The hydroconversion reaction zone is sequentially filled with hydroconversion catalyst I and hydroconversion catalyst II along the flow direction. The volume ratio of hydroconversion catalyst I to hydroconversion catalyst II is 1:3 to 3:1, preferably 1:2 to 2:1.

[0009] According to the present invention, a fixed-bed reactor is used for the hydrogenation conversion reaction.

[0010] According to the present invention, hydroconversion catalyst I comprises a ZSM-5 molecular sieve and an active metal component, wherein the active metal component is selected from one or more Group VIB metals and Group VIII non-noble metals of the periodic table, wherein 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. Hydroconversion catalyst II comprises mordenite zeolite and an active metal component, wherein the active metal component is selected from one or more Group VIB metals and Group VIII non-noble metals of the periodic table, wherein 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.

[0011] According to the present invention, the hydroconversion reaction zone is sequentially filled with hydroconversion catalyst I and hydroconversion catalyst II along the material flow direction, that is, the material first contacts hydroconversion catalyst I to react, and then contacts hydroconversion catalyst II to react. Hydroconversion catalyst I and hydroconversion catalyst II can be graded and filled in one catalyst bed or multiple catalyst beds along the material flow direction.

[0012] According to the present invention, the initial boiling point of the sulfur-containing naphtha is 10-30°C, preferably 15-25°C, and the final boiling point is 50-100°C, preferably 55-70°C.

[0013] According to the present invention, the sulfur in the sulfur-containing naphtha is introduced externally, including organic sulfur and / or inorganic sulfur, wherein the organic sulfur includes one or more of disulfides, thiols and thioethers, and the inorganic sulfur includes hydrogen sulfide.

[0014] According to the present invention, the sulfur content in the sulfur-containing naphtha is 50-20000 mg / kg, preferably 200-10000 mg / kg, for example, it can be 200 mg / kg, 500 mg / kg, 800 mg / kg, 1000 mg / kg, 1500 mg / kg, 2000 mg / kg, 2500 mg / kg, 3000 mg / kg, 3500 mg / kg, 4000 mg / kg, 5000 mg / kg, 6000 mg / kg, 7000 mg / kg, 8000 mg / kg, 9000 mg / kg, 10000 mg / kg, and any range between any two values.

[0015] According to the present invention, the sulfur content in the hydrogenation conversion product is 50-200 mg / kg, preferably 100-200 mg / kg.

[0016] According to the present invention, the sulfur-containing naphtha contains 60 wt% to 90 wt% C5-C6 isoalkanes, preferably 70 wt% to 80 wt%; C7 + 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%; C4 - The 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 sulfur-containing naphtha is 100 wt%.

[0017] According to the present invention, the active metal mass content of hydroconversion catalyst I, calculated as oxides, is 1 to 20 percentage points higher than that of hydroconversion catalyst II, preferably 5 to 10 percentage points higher.

[0018] According to the present invention, in the hydroconversion catalyst I, the SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 10-50, and the specific surface area is 300-500 m². 2 / g, with a pore volume of 0.2–0.4 mL / g. In the hydroconversion catalyst II, the SiO2 / Al2O3 molar ratio of mordenite is 10–50, and the specific surface area is 300–600 m² / g. 2 / g, with a pore volume of 0.15~0.35mL / g.

[0019] Furthermore, in the hydroconversion catalyst I, the content of ZSM-5 molecular sieve is 30wt% to 80wt%, preferably 40wt% to 70wt%, based on the weight of catalyst I.

[0020] According to the present invention, the hydroconversion catalyst I further includes a binder, which is preferably alumina. Further, in the hydroconversion catalyst I, based on the weight of catalyst I, the content of the binder as an oxide is 5 wt% to 65 wt%, preferably 10 wt% to 35 wt%.

[0021] According to the present invention, in the hydroconversion catalyst I, the content of the Group VIB metal (calculated as oxide) is 5 wt% to 30 wt%, preferably 10 wt% to 20 wt%, based on the weight of the catalyst I; and the content of the Group VIII non-noble metal (calculated as oxide) is 0.5 wt% to 15 wt%, preferably 3 wt% to 10 wt%.

[0022] According to the present invention, the specific surface area of ​​the hydroconversion catalyst I is 200-400 m². 2 / g, with a pore volume of 0.15~0.40mL / g.

[0023] According to the present invention, the preparation method of the hydroconversion catalyst I 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 support preparation process is as follows: ZSM-5 molecular sieve and 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.

[0024] According to the present invention, in the preparation method of the hydroconversion catalyst I, the method for 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.

[0025] Furthermore, in the hydroconversion catalyst II, the content of mordenite is 30wt% to 80wt%, preferably 40wt% to 70wt%, based on the weight of the catalyst II.

[0026] According to the present invention, the hydroconversion catalyst II further includes a binder, which is preferably alumina. Further, in the hydroconversion catalyst II, the binder content, based on the weight of catalyst II, is 5 wt% to 65 wt%, preferably 10 wt% to 35 wt% as an oxide.

[0027] According to the present invention, the hydroconversion catalyst II contains, based on the weight of catalyst II, a group VIB metal (calculated as oxide) of 5 wt% to 30 wt%, preferably 10 wt% to 20 wt%; and a group VIII non-noble metal (calculated as oxide) of 0.5 wt% to 15 wt%, preferably 3 wt% to 10 wt%.

[0028] According to the present invention, the specific surface area of ​​the hydroconversion catalyst II is 200-400 m². 2 / g, with a pore volume of 0.15~0.40mL / g.

[0029] According to the present invention, the preparation method of the hydroconversion catalyst II 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: mordenite molecular sieve and a binder are mechanically mixed, shaped, dried, and calcined to form the catalyst support. The drying and calcination of the support can be performed 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.

[0030] According to the present invention, in the preparation method of the hydroconversion catalyst II, the method for 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.

[0031] According to the present invention, preferably, the mass content of Group VIB metals in hydroconversion catalyst I, calculated as oxides, is 1 to 18 percentage points higher (preferably 2 to 10 percentage points higher) than the mass content of Group VIB metals in hydroconversion catalyst II, and the mass content of Group VIII non-precious metals in hydroconversion catalyst I, calculated as oxides, is 0 to 4 percentage points higher than the mass content of Group VIII non-precious metals in hydroconversion catalyst II, calculated as oxides.

[0032] 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.

[0033] According to the present invention, the reaction effluent from the hydrogenation conversion reaction zone is fed into a separation system, and the separated hydrogen-rich gas can be used as recycled hydrogen.

[0034] According to the present invention, the hydroconversion products are directly fed into a steam cracking ethylene production unit to obtain the main target products ethylene, propylene, and butadiene, wherein the yields of the trienes are the mass percentages of the ethylene, propylene, and butadiene production relative to the hydroconversion product feed. The operating conditions for the steam cracking ethylene production are: reaction temperature 860–890°C, reaction pressure 0.1–0.3 MPa, and water-to-oil mass ratio 0.2–0.6.

[0035] For small-molecule isoalkanes, the hydrogenation conversion process mainly involves three reaction processes: hydrocracking, where isoalkanes are directly broken down into smaller molecules; normalization, where isoalkanes are hydrogenated to produce normal alkanes with the same number of carbon atoms; and disproportionation, where a methyl group from one isoalkane molecule is transferred to another. In the hydrogenation conversion process, the first step is dehydrogenation. The inventors have discovered that C6 isoalkanes are less prone to normalization and more easily undergo cracking to produce smaller-molecule alkanes, while C5 isoalkanes are more likely to undergo normalization.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] (1) Hydrocracking light naphtha mainly contains C5 and C6 isoalkanes. The inventors have found that as the molecular weight increases, the difficulty of ortho-alkanization reactions gradually increases, with C6 components being more prone to cracking reactions. The reactivity of hydroconversion catalysts is mainly affected by hydrotreating performance, while the reaction process for isoalkanes is mainly influenced by acidic centers, i.e., molecular sieves. The inventors have found that mordenite zeolite with a high content of medium-strong acids tends to undergo ortho-alkanization reactions during hydroconversion, while ZSM-5 molecular sieves with a high content of strong acids tend to undergo cracking reactions. Using these two molecular sieves with different reaction characteristics for gradation can achieve efficient conversion of different molecular hydrocarbons. Further research by the inventors revealed that using a ZSM-5 molecular sieve catalyst with high active metal content can improve the cracking performance of the hydroconversion catalyst, preferentially hydrocracking C6 isoalkanes. Then, a mordenite catalyst with lower active metal content can further promote the normalization reaction of C5 isoalkanes, fully leveraging the catalytic effects of both molecular sieve catalysts. This approach can increase the proportion of normal hydrocarbons in the hydrogenation products while effectively reducing hydrogen consumption.

[0038] (2) In the process of producing ethylene by steam cracking, the sulfur content of the feedstock needs to be controlled to a certain extent. If the sulfur content is too low, sulfur needs to be injected before the cracking furnace, otherwise it will accelerate the coking of the ethylene cracking furnace, affecting the operating cycle and cracking effect; while if the sulfur content in the feedstock is too high, it will increase the operating cost of subsequent desulfurization. The inventors have found through research that when producing ethylene feedstock through hydrogenation reaction, by processing sulfur-containing feedstock and controlling the appropriate sulfur content in the hydrogenation products, the sulfur content in the feedstock of the ethylene unit can be effectively controlled, reducing or even eliminating the amount of sulfur injected into the ethylene cracking furnace.

[0039] (3) During the hydrogenation reaction of sulfur-containing hydrocarbon feedstocks, organic sulfides are converted into hydrogen sulfide. This hydrogen sulfide is a worthless product for the hydrogenation unit and may even require removal through separation methods such as stripping. The removed hydrogen sulfide also requires subsequent harmless treatment. This invention uses hydrogenation products containing a certain amount of hydrogen sulfide as ethylene feedstock, which not only solves the problem of sulfur injection into ethylene production units but also achieves high-value utilization of the useless components. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention;

[0041] Explanation of key figure labels:

[0042] 1-Sulfur-containing naphtha, 2-Hydrogen gas, 3-Hydroconversion reaction zone, 4-Hydroconversion reaction zone effluent, 5-Separation system, 6-Hydrogen-rich gas, 7-Hydroconversion products. Detailed Implementation

[0043] 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.

[0044] Unless otherwise specified, all percentages in this invention refer to mass fractions.

[0045] The method of the present invention, such as Figure 1 As shown, the process includes: sulfur-containing naphtha 1 and hydrogen 2 are mixed and enter the hydroconversion reaction zone 3 for hydroconversion reaction; the hydroconversion reaction effluent 4 enters the separation system 5; the separated hydrogen-rich gas 6 is recycled; and the hydroconversion product 7 is used directly as ethylene feedstock.

[0046] In this invention, the yield of n-alkane = n-alkane yield in hydrogenation conversion products / fresh feed amount × 100%, by mass.

[0047] 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 in each example are designated as Cat-B followed by a number, such as Cat-B1, Cat-B2, Cat-B3, and Cat-B4. 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.

[0048] In this invention, the properties of the ZSM-5 molecular sieve used in Cat-A are as follows: SiO2 / Al2O3 molar ratio is 30, and specific surface area is 400 m². 2 / g, pore volume 0.25cm 3 / g; The properties of the mordenite used in Cat-B are as follows: SiO2 / Al2O3 molar ratio is 20, and specific surface area is 450m². 2 / g, pore volume 0.25cm 3 / g.

[0049] In this invention, sulfur-containing naphtha is used as hydrocracked light naphtha with added sulfur compounds in each example, and its main properties are shown in Table 3. The sulfur-containing compound is hydrogen sulfide.

[0050] In this invention, the n-alkanes in Tables 4-5 include ethane, propane, n-butane, n-pentane, and n-hexane.

[0051] In this invention, the sulfur content of the naphtha in each example is less than 5 ppm.

[0052] Example 1

[0053] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0054] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A1 and Cat-B1;

[0055] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0056] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0057] Example 2

[0058] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0059] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A2 and Cat-B2.

[0060] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0061] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0062] Example 3

[0063] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0064] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A3 and Cat-B3.

[0065] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0066] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0067] Example 4

[0068] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0069] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A1 and Cat-B3.

[0070] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0071] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0072] Example 5

[0073] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0074] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A4 and Cat-B1;

[0075] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0076] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0077] Example 6

[0078] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0079] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A1 and Cat-B5;

[0080] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

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

[0082] Example 7

[0083] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0084] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A3 and Cat-B4.

[0085] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0086] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0087] Example 8

[0088] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0089] (1) Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with hydroconversion Cat-A4 and Cat-B2.

[0090] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the separation system. The hydrogen-rich gas obtained from the separation is used as recycled hydrogen, and the hydrogenation conversion product is used directly as ethylene feedstock.

[0091] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0092] Comparative Example 1

[0093] The difference from Example 1 is that the hydroconversion reaction zone is only filled with one type of hydroconversion catalyst, Cat-A1.

[0094] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0095] Comparative Example 2

[0096] The difference from Example 1 is that the hydroconversion reaction zone is only filled with one type of hydroconversion catalyst, Cat-B1.

[0097] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0098] Comparative Example 3

[0099] The difference from Example 1 is that the hydroconversion reaction zone is sequentially filled with hydroconversion catalysts Cat-A3 and Cat-B1.

[0100] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0101] Comparative Example 4

[0102] The difference from Example 1 is that the hydrogenation conversion reaction zone is sequentially filled with catalysts Cat-A1 and Cat-B4.

[0103] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0104] Table 1. Composition and physicochemical properties of hydroconversion catalysts

[0105]

[0106]

[0107] Table 2 Composition and physicochemical properties of hydroconversion catalysts

[0108] Catalyst number Cat-B1 Cat-B2 Cat-B3 Cat-B4 Cat-B5 Catalyst properties <![CDATA[Pore volume, cm 3 / g]]> 0.25 0.26 0.26 0.28 0.30 <![CDATA[Specific surface area, m 2 / g]]> 308 310 315 346 355 Catalyst composition Siliceous zeolite, wt% 50 50 50 50 60 Alumina, wt% 30 32 35 46 15 <![CDATA[MoO3,wt%]]> 15 13 10 3 20 NiO, wt% 5 5 5 1 5

[0109] Table 3. Main Properties of Sulfur-Containing Naphtha

[0110] raw material Sulfur-containing 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[C7 + Hydrocarbon and cyclic hydrocarbon content, wt% 3 Initial boiling point, ℃ 24 Final boiling point, ℃ 64

[0111] Table 4. Process conditions and conversion results of each embodiment

[0112]

[0113]

[0114] Table 4 continues with the process conditions and conversion results of each embodiment.

[0115]

[0116] Table 5. Process conditions and conversion results for each comparative example.

[0117]

[0118] Application examples

[0119] The hydrogenation conversion products obtained in Examples 1, 2, 7, 8, and Comparative Example 4 of this invention were fed into a steam cracking ethylene production unit to obtain the main target products ethylene, propylene, and butadiene. The operating conditions for the steam cracking ethylene production were: reaction temperature 880°C, reaction pressure 0.2 MPa, and water-to-oil mass ratio 0.4. The reaction results are shown in Table 6.

[0120] Table 6

[0121]

[0122]

[0123] 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 the hydroconversion of sulfur-containing naphtha, the method comprising: Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction. The reaction effluent enters a separation system to separate hydrogen-rich gas and hydroconversion products. The hydroconversion reaction zone is sequentially filled with hydroconversion catalyst I and hydroconversion catalyst II along the flow direction. The volume ratio of hydroconversion catalyst I to hydroconversion catalyst II is 1:3 to 3:1, preferably 1:2 to 2:

1.

2. The method according to claim 1, characterized in that, Hydroconversion catalyst I comprises ZSM-5 molecular sieve and an active metal component. The active metal component is selected from one or more Group VIB metals and Group VIII non-precious metals. The Group VIB metal is selected from one or more molybdenum and tungsten, and the Group VIII non-precious metal is selected from one or more cobalt and nickel. Preferably, in the hydroconversion catalyst I, based on the weight of catalyst I, the content of ZSM-5 molecular sieve is 30wt% to 80wt%, preferably 40wt% to 70wt%; the content of Group VIB metals as oxides is 5wt% to 30wt%, preferably 10wt% to 20wt%; and the content of Group VIII non-precious metals as oxides is 0.5wt% to 15wt%, preferably 3wt% to 10wt%.

3. The method according to claim 1, characterized in that, Hydroconversion catalyst II comprises mordenite and an active metal component, wherein the active metal component is selected from one or more Group VIB metals and Group VIII non-precious metals, wherein the Group VIB metal is selected from one or more molybdenum and tungsten, and the Group VIII non-precious metal is selected from one or more cobalt and nickel; Preferably, in the hydroconversion catalyst II, based on the weight of catalyst II, the content of mordenite is 30wt% to 80wt%, preferably 40wt% to 70wt%; the content of Group VIB metals as oxides is 5wt% to 30wt%, preferably 10wt% to 20wt%; and the content of Group VIII non-precious metals as oxides is 0.5wt% to 15wt%, preferably 3wt% to 10wt%.

4. The method according to claim 1, characterized in that, The sulfur content in sulfur-containing naphtha is 50-20000 mg / kg, preferably 200-10000 mg / kg; And / or, the sulfur content in the hydrogenation conversion product is 50-200 mg / kg, preferably 100-200 mg / kg.

5. The method according to claim 1, characterized in that, The initial boiling point of sulfur-containing naphtha is 10-30℃, preferably 15-25℃, and the final boiling point is 50-100℃, preferably 55-70℃.

6. The method according to claim 1, characterized in that, In sulfur-containing naphtha, the content of C5-C6 isoalkanes is 60wt%–90wt%, preferably 70wt%–80wt%; C7 + 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%; C4 - The 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%.

7. The method according to claim 1, characterized in that, The active metal mass content of hydroconversion catalyst I, calculated as oxides, is 1 to 20 percentage points higher than that of hydroconversion catalyst II, preferably 5 to 10 percentage points higher.

8. The method according to claim 1 or 7, characterized in that, The mass content of Group VIB metals in hydroconversion catalyst I, calculated as oxides, is 1–18 percentage points higher than that in hydroconversion catalyst II, calculated as oxides. The mass content of Group VIII non-precious metals in hydroconversion catalyst I, calculated as oxides, is 0–4 percentage points higher than that in hydroconversion catalyst II, calculated as oxides.

9. The method according to claim 1, characterized in that, The hydroconversion reaction conditions are as follows: reaction pressure 0.5 MPa–10.0 MPa, reaction temperature 250 °C–500 °C, and liquid hourly space velocity (LHSV) 0.1 h⁻¹. -1 ~15.0h -1 The hydrogen-to-oil volume ratio is 10:1 to 2500:

1.

10. The method according to claim 1, characterized in that, The hydroconversion reaction conditions are as follows: reaction pressure 2.0 MPa–5.0 MPa; reaction temperature 350 °C–450 °C; liquid hourly space velocity (LISH) 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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