A method for the production of high value-added products from ethylene cracking tar

Abstract

The application discloses a method for cracking tar into high value-added products, which adopts a route of separating light components by fractional distillation and then hydrogenating heavy components, so that the yield of target products can be affected by hydrogenation of naphthalene, methyl naphthalene and the like below 250 DEG C in the process of hydrocracking, and on the other hand, the components below 250 DEG C account for about 30% to 50%, so that the hydrogen consumption in the subsequent hydrocracking can be reduced by separating the components in advance. After the heavy fraction is subjected to hydrocracking, part of polycyclic aromatic hydrocarbons in the heavy fraction can be cracked into part of monocyclic aromatic hydrocarbons, which can be used for producing aromatic solvent oil, so that the light fraction in the hydrocracking product is separated and mixed into the light fraction generated by pre-fractionation, and the next step processing is carried out, so that the yield of high value-added products can be further improved.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, specifically relating to a method for producing high-value-added products from ethylene cracking tar. Background Technology

[0002] Ethylene cracking tar is a product of high-temperature condensation of raw materials in the ethylene production process. After cracking, ethylene cracking tar is produced. Its main components are a mixture of polycyclic aromatic hydrocarbons with bicyclic rings or more. It is characterized by short side chains, high carbon-hydrogen ratio, low ash content, and very low heavy metal content. Most of it is mainly used as boiler fuel oil, and its economic value is relatively low.

[0003] CN112391200A discloses a method for hydrogenating ethylene cracking tar in a slurry bed reactor. This method involves mixing a metal sulfide catalyst with ethylene cracking tar to obtain a first mixture, which is then fed into a slurry bed reactor for reaction. A second mixture and hydrogen are then fed into the slurry bed reactor for a second reaction. The resulting hydrogenated products are separated under atmospheric and vacuum pressure. The obtained components are gasoline and diesel fuel rich in light aromatics with a boiling range below 360°C; wax oil components with a boiling range of 360°C-480°C are exported; and the mixture with a boiling range above 480°C is used as residue from the ethylene cracking tar and recycled as feedstock in the first step. This technology employs full-range hydrogenation to hydrogenate valuable bicyclic compounds such as naphthalene and methylnaphthalene. The main products are gasoline, diesel fuel, and wax oil components; no high-value-added products are produced.

[0004] CN1970688A discloses a comprehensive processing technology for extracting industrial naphthalene and methylnaphthalene from ethylene tar. This process first fractionates the ethylene tar at 260–280°C, separating the light fraction, which is then hydrorefined to remove unsaturated hydrocarbons. Further distillation separates refined naphthalene, α-methylnaphthalene, β-methylnaphthalene, and solvent oil. However, this technology only refines the fractions below 280°C, while the heavier fractions are mostly used as fuel. Furthermore, because the heavier fractions are richer in polycyclic aromatic hydrocarbons than ethylene cracking tar, they are more prone to coking, causing environmental pollution. Summary of the Invention

[0005] The purpose of this invention is to provide a method for producing more high-value-added products from ethylene cracking tar, in order to solve the problems of low overall utilization rate and low economic benefits of ethylene cracking tar in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for producing high-value-added products from ethylene cracking tar, comprising the following steps:

[0007] S1, ethylene tar is fractionated into light fraction L1 and heavy fraction H1 in a pre-fractionation tower, with a cutting temperature of 240-270℃;

[0008] S2, heavy fraction H1 is mixed with nano-sized oil-soluble metal catalyst and then subjected to hydrocracking reaction to obtain hydrocracking product S1;

[0009] S3, the hydrocracking product S1 is distilled under atmospheric pressure at a cutting temperature of 240-270℃ to obtain light fraction L2 and bottom heavy fraction S2.

[0010] S4, the heavy fraction S2 is distilled under reduced pressure to separate into three fractions. The reduced pressure distillation operation pressure is 10-30 mmHg. The fraction between (250-260℃) and (330-350℃) is the heavy fraction H2; the fraction between (330-350℃) and (500-520℃) is the heavy fraction H3; and the fraction above 500-520℃ is the heavy fraction H4.

[0011] S5, after mixing light fractions L1 and L2, is distilled to obtain raw materials for hydrogenation to produce high aromatic solvent oil, crude naphthalene, and mixed methyl naphthalene;

[0012] S6, the heavy fraction H2 is hydrotreated to obtain diesel blending components, the heavy fraction H3 is used as raw material for the production of mesophase asphalt, needle coke, carbon black and other products; the heavy fraction H4 is the external tailings.

[0013] The method for producing high-value-added products from ethylene cracking tar according to the present invention has a cutting temperature of 250-260°C in step S1.

[0014] The method for producing high-value-added products from ethylene cracking tar according to the present invention includes a nano-sized oil-soluble metal catalyst with a particle size between 3 nm and 50 nm in step S2, a reaction temperature of 380 to 430°C, a pressure of 8 to 16 MPa, and a reaction time of 1 to 3 h.

[0015] The method for producing high-value-added products from ethylene cracking tar according to the present invention, wherein the active component of the nano-scale oil-soluble metal catalyst in step S2 is a metal sulfide; the metal type is one or more of Mo, Ni, and Co, preferably Mo; and the catalyst concentration, based on the metal content, is 100 to 1000 ppm.

[0016] The hydrocracking reaction described in step S2 can be carried out in commonly used devices in the field, such as slurry bed hydrocracking reactors, continuous autoclaves, and batch autoclaves. This application does not impose any special limitations, and those skilled in the art can choose according to the actual situation.

[0017] The method for producing high-value-added products from ethylene cracking tar according to the present invention has a cutting temperature of 245-255°C in step S3.

[0018] The method for producing high-value-added products from ethylene cracking tar according to the present invention, wherein the operating pressure of vacuum distillation in step S4 is 15-25 mmHg.

[0019] The method for producing high-value-added products from ethylene cracking tar according to the present invention includes a distillation process in step S5, which is carried out in two distillation columns. The top temperature of the first distillation column is 205-210°C, and the top fraction is the feedstock for hydrogenation to produce high-aromatic solvent oil. The bottom material enters the second distillation column, which has a top temperature of 210-230°C, and the top fraction is crude naphthalene. The bottom fraction of the second distillation column is mixed methylnaphthalene.

[0020] The method for producing high-value-added products from ethylene cracking tar according to the present invention employs a two-stage hydrogenation process when producing high-aromatic solvent oil from the feedstock obtained in step S5. The first-stage hydrogenation process uses a Ni-based selective hydrogenation catalyst, with a reaction temperature of 30–100°C, a pressure of 1–3 MPa, and a space velocity of 1–3 h⁻¹. -1 The hydrogen-to-oil ratio is 100–400; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfide catalyst, with a reaction temperature of 240–270℃, a pressure of 1–3 MPa, and a space velocity of 1–3 h⁻¹. -1 The hydrogen-to-oil ratio is 300–500.

[0021] The Ni-based selective hydrogenation catalyst described in this invention is a commonly used catalyst in the art, mainly composed of NiO supported on alumina. The additives added to the catalyst can be one or more of K, Mo, and Zn, which can be selected by those skilled in the art according to actual conditions; this application does not impose any special limitations. The cobalt-molybdenum-nickel-based sulfidation catalyst described in this invention is a commonly used catalyst in the art, mainly composed of CoO-MoO3-NiO supported on alumina. Sulfidation is required before start-up; the specific sulfidation conditions are conventional methods in the art, which can be selected by those skilled in the art according to actual conditions; this application does not impose any special limitations.

[0022] The beneficial effects of this invention are:

[0023] 1. This process adopts a route of first separating the light components by fractionation and then hydrogenating the heavy components. On the one hand, this can avoid the hydrogenation of naphthalene, methylnaphthalene, etc. below 250°C to form tetrahydronaphthalene, etc. during the hydrocracking process, which would affect the yield of the target product. On the other hand, the components below 250°C account for about 30% to 50%. Separating this part in advance can also reduce the hydrogen consumption in the subsequent hydrocracking.

[0024] 2. Hydrocracking of polycyclic aromatic hydrocarbons (PAHs), gums, and asphaltenes in the heavy fraction H1 can induce chain scission reactions in some PAHs, increasing the yield of light aromatic hydrocarbons and achieving desulfurization and impurity removal, thus providing higher-quality feedstock for subsequent product processing. If traditional fixed-bed residue hydrocracking catalysts are used, the high PAH content and viscosity of the heavy fraction (approximately solid at room temperature) easily lead to coking and clogging of the catalyst channels, resulting in catalyst deactivation, making it difficult to achieve the desired effect. However, this invention uses a nano-scale, self-sulfurizing, oil-soluble molybdenum-based catalyst, which can be highly dispersed in the heavy fraction H1, exhibiting excellent hydrocracking and coking suppression effects. Fresh catalyst is continuously replenished, eliminating this problem. The feedstock undergoes hydrocracking under certain conditions, and the conversion rate and hydrocracking depth can be controlled by adjusting the reaction conditions according to product structure requirements.

[0025] 3. The inventors discovered in experiments that after hydrocracking the heavy fraction, some of the polycyclic aromatic hydrocarbons in the heavy fraction can be cracked to generate some monocyclic aromatic hydrocarbons, which can be used to produce aromatic solvent oil. Therefore, separating the light fraction from the hydrocracking product and mixing it with the light fraction produced by pre-fractionation for further processing can further improve the yield of high value-added products. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of the ethylene cracking tar process described in this invention, which aims to produce high-value-added products. Detailed Implementation

[0027] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0028] The ethylene tar used in the following examples is all Daqing Petrochemical ethylene cracking tar, and the properties of the raw materials are shown in Table 1.

[0029] The oil-soluble nano-molybdenum disulfide catalyst used is catalyst Y-1 from Example 1 of patent application number 202011257522.1. This catalyst has self-sulfidation function and decomposes during the heating process to obtain nano-molybdenum disulfide with a length of 2-8 nm, mainly in the form of single-layer plates. The nickel-based selective hydrogenation catalyst is the nickel-based hydrogenation catalyst (LY-2008) independently developed by the Lanzhou Chemical Research Center of China National Petroleum Corporation. The cobalt-molybdenum-nickel sulfidation catalyst is the hydrogenation catalyst (LY-9802) independently developed by the Lanzhou Chemical Research Center of China National Petroleum Corporation.

[0030] Table 1 Properties of Ethylene Crack Tar Feedstock

[0031]

[0032]

[0033] Example 1:

[0034] Example 1 uses the process flow of the present invention, and the specific process flow diagram is attached. Figure 1 The method is as follows:

[0035] 1000g of ethylene cracking tar was divided into light fraction L1 and heavy fraction H1 in a pre-fractionation tower at a cut-off point of 250℃.

[0036] The obtained heavy fraction H1 was mixed evenly with oil-soluble nano-molybdenum disulfide catalyst and placed in a high-pressure reactor. The catalyst addition amount was 300 ppm, the reaction temperature was set at 390℃, the hydrogen pressure was 10 MPa, and the reaction was carried out for 2 hours to obtain hydrocracking product S1.

[0037] Product S1 was subjected to atmospheric distillation at a distillation temperature of 270℃, yielding a light fraction L2. The heavy fraction at the bottom of the distillate was further subjected to vacuum distillation at an operating pressure of 10 mmHg. From the distillate, the fraction with a boiling point equivalent to 250℃–340℃ under atmospheric pressure was designated as heavy fraction H2, the fraction with a boiling point equivalent to 340℃–500℃ was designated as heavy fraction H3, and the fraction with a boiling point greater than 500℃ was designated as heavy fraction H4.

[0038] The light fractions L1 and L2 are mixed and then subjected to two distillations to obtain three fractions: the top fraction of the first distillation column is P1, which is below 210°C and can be used as a feedstock for the hydrogenation production of high aromatic solvent oil; the bottom product enters the second distillation column, the top fraction of the second distillation column is P2, which is 210-230°C and mainly consists of crude naphthalene; the bottom fraction of the second distillation column is P3, which is 230-250°C and mainly consists of mixed methylnaphthalene.

[0039] The production of high-aromatic solvent oil employs a low-pressure two-stage hydrogenation process: the first stage hydrogenation uses a nickel-based selective hydrogenation catalyst, primarily composed of alumina-supported NiO. The operating conditions for the first-stage hydrogenation reaction are: temperature 50℃, pressure 1.5 MPa, and space velocity 1.5 h⁻¹. -1 The hydrogen-to-oil ratio is 150; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfidation catalyst, mainly composed of alumina-supported CoO-MoO3-NiO; CS2 needs to be introduced for sulfidation before start-up; the operating conditions for the two-stage hydrogenation reaction are: temperature 245℃, pressure 1MPa, and space velocity 1h. -1 The hydrogen-to-oil ratio is 300.

[0040] Heavy fraction H2 is hydrorefined in a fixed-bed reactor to obtain diesel blending components. Heavy fraction H3 is sent externally as feedstock for the production of mesophase asphalt, needle coke, carbon black, and other products. Heavy fraction H4 is sent externally as tailings to a gasification unit for tailings gasification.

[0041] The distribution of the products and some product properties in this embodiment are shown in Table 3.

[0042] Example 2:

[0043] Example 2 adopts the process flow of the present invention, and the specific process flow diagram is attached. Figure 1 The method is as follows:

[0044] 1000g of ethylene cracking tar was divided into light fraction L1 and heavy fraction H1 in a pre-fractionation tower at a cut-off point of 260℃.

[0045] The obtained heavy fraction H1 was mixed evenly with oil-soluble nano-molybdenum disulfide catalyst and placed in a high-pressure reactor. The catalyst addition amount was 700 ppm, the reaction temperature was set at 420℃, the hydrogen pressure was 14 MPa, and the reaction was carried out for 2 hours to obtain hydrocracking product S1.

[0046] Product S1 was subjected to atmospheric distillation at a distillation temperature of 250℃, yielding the light fraction L2. The heavy fraction at the bottom of the distillate was further subjected to vacuum distillation at an operating pressure of 25 mmHg. The fraction with a boiling point of 260℃ to 350℃ at atmospheric pressure was designated as heavy fraction H2, the fraction with a boiling point of 350℃ to 520℃ as heavy fraction H3, and the fraction with a boiling point above 520℃ as heavy fraction H4.

[0047] The light fractions L1 and L2 are mixed and then subjected to two distillations to obtain three fractions: the top fraction of the first distillation column is P1, which is below 210°C and can be used as a feedstock for the hydrogenation production of high aromatic solvent oil; the bottom product enters the second distillation column, the top fraction of the second distillation column is P2, which is 210-230°C and mainly consists of crude naphthalene; the bottom fraction of the second distillation column is P3, which is 230-250°C and mainly consists of mixed methylnaphthalene.

[0048] The production of high-aromatic solvent oil employs a low-pressure two-stage hydrogenation process: the first stage hydrogenation uses a nickel-based selective hydrogenation catalyst, primarily composed of alumina-supported NiO. The operating conditions for the first-stage hydrogenation reaction are: temperature 80℃, pressure 2.5 MPa, and space velocity 2.5 h⁻¹. -1 The hydrogen-to-oil ratio is 400; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfidation catalyst, mainly composed of alumina-supported CoO-MoO3-NiO; CS2 needs to be introduced for sulfidation before start-up; the operating conditions for the two-stage hydrogenation reaction are: temperature 260℃, pressure 2.5MPa, and space velocity 2.5h⁻¹. -1 The hydrogen-to-oil ratio is 450.

[0049] Heavy fraction H2 is hydrorefined in a fixed-bed reactor to obtain diesel blending components. Heavy fraction H3 is sent externally as feedstock for the production of mesophase asphalt, needle coke, carbon black, and other products. Heavy fraction H4 is sent externally as tailings to a gasification unit for tailings gasification.

[0050] The distribution of the products and some product properties in this embodiment are shown in Table 3.

[0051] Comparative Example 1:

[0052] Comparative Example 1 employs a conventional process for full-fraction hydrocracking of ethylene cracking tar. The method is as follows:

[0053] 1000g of ethylene cracking tar was mixed evenly with oil-soluble nano-molybdenum disulfide catalyst and placed in a high-pressure reactor. The catalyst dosage was 500ppm, the reaction temperature was set at 420℃, the hydrogen pressure was 12MPa, and the reaction was carried out for 2 hours to obtain hydrocracking product S1.

[0054] Product S1 was subjected to atmospheric distillation at a distillation temperature of 250℃, yielding the light fraction L1. The heavy fraction at the bottom of the distillate was further subjected to vacuum distillation at an operating pressure of 20 mmHg. From the distillate, the fraction with a boiling point of 250℃ to 340℃ under atmospheric pressure was designated as heavy fraction H2, the fraction with a boiling point of 340℃ to 500℃ was designated as heavy fraction H3, and the fraction with a boiling point greater than 500℃ was designated as heavy fraction H4.

[0055] The light fraction L1 is subjected to two distillations to obtain three fractions: the top fraction of the first distillation column is P1, which is below 210°C and can be used as a feedstock for the hydrogenation production of high aromatic solvent oil; the bottom product enters the second distillation column, the top fraction of the second distillation column is P2, which is 210-230°C and mainly consists of crude naphthalene; the bottom fraction of the second distillation column is P3, which is 230-250°C and mainly consists of mixed methylnaphthalene.

[0056] The production of high-aromatic solvent oil employs a low-pressure two-stage hydrogenation process: the first stage hydrogenation uses a nickel-based selective hydrogenation catalyst, mainly composed of alumina-supported NiO. The operating conditions for the first-stage hydrogenation reaction are: temperature 70℃, pressure 2.5MPa, and space velocity 2h⁻¹. -1 The hydrogen-to-oil ratio is 400; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfidation catalyst, mainly composed of alumina-supported CoO-MoO3-NiO; CS2 needs to be introduced for sulfidation before start-up; the operating conditions for the two-stage hydrogenation reaction are: temperature 250℃, pressure 2.5MPa, and space velocity 2h⁻¹. -1 The hydrogen-to-oil ratio is 400.

[0057] Heavy fraction H2 is hydrorefined in a fixed-bed reactor to obtain diesel blending components. Heavy fraction H3 is sent externally as feedstock for the production of mesophase asphalt, needle coke, carbon black, and other products. Heavy fraction H4 is sent externally as tailings to a gasification unit for tailings gasification.

[0058] The distribution of the products in this comparative example and the properties of some products are shown in Table 3.

[0059] Comparative Example 2

[0060] 1000g of ethylene cracking tar was directly distilled under atmospheric pressure at a distillation temperature of 250℃, yielding a light fraction L1. The heavy fraction at the bottom of the distillate was further distilled under reduced pressure at an operating pressure of 20mmHg. The fraction with a boiling point equivalent to 250℃–340℃ under atmospheric pressure was designated as heavy fraction H2, the fraction with a boiling point equivalent to 340℃–500℃ as heavy fraction H3, and the fraction with a boiling point greater than 500℃ as heavy fraction H4.

[0061] The light fraction L1 is subjected to two distillations to obtain three fractions: the top fraction of the first distillation column is P1, which is below 210°C and can be used as a feedstock for the hydrogenation production of high aromatic solvent oil; the bottom product enters the second distillation column, the top fraction of the second distillation column is P2, which is 210-230°C and mainly consists of crude naphthalene; the bottom fraction of the second distillation column is P3, which is 230-250°C and mainly consists of mixed methylnaphthalene.

[0062] The production of high-aromatic solvent oil employs a low-pressure two-stage hydrogenation process: the first stage hydrogenation uses a nickel-based selective hydrogenation catalyst, mainly composed of alumina-supported NiO. The operating conditions for the first-stage hydrogenation reaction are: temperature 70℃, pressure 2.5MPa, and space velocity 2h⁻¹. -1 The hydrogen-to-oil ratio is 400; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfidation catalyst, mainly composed of alumina-supported CoO-MoO3-NiO; CS2 needs to be introduced for sulfidation before start-up; the operating conditions for the two-stage hydrogenation reaction are: temperature 250℃, pressure 2.5MPa, and space velocity 2h⁻¹. -1 The hydrogen-to-oil ratio is 400.

[0063] Heavy fraction H2 is hydrorefined in a fixed-bed reactor to obtain diesel blending components. Heavy fraction H3 is sent externally as feedstock for the production of mesophase asphalt, needle coke, carbon black, and other products. Heavy fraction H4 is sent externally as tailings to a gasification unit for tailings gasification.

[0064] The distribution of the products and some product properties in this embodiment are shown in Table 3.

[0065] Table 2 Hydrocracking process conditions in each example and comparative example

[0066] project Example 1 Example 2 Comparative Example 1 Raw material type >250℃ fraction >250℃ fraction Full fraction Catalyst concentration / ppm 300 500 500 Pressure / MPa 10 12 12 Temperature / °C 390 420 420 Reaction time / h 2 2 2

[0067] Table 3 Product Distribution and Properties of Some Products

[0068]

[0069] Examples 1 and 2 employ the process described in this invention, while Comparative Example 1 uses a full-fraction hydrogenation process. By comparing the yields of each fraction, the content of monocyclic aromatic hydrocarbons in product P1, the content of naphthalene in product P2, and the content of mixed methylnaphthalene in product P3, it can be seen that although the yields of the three fractions P1, P2, and P3 below 250°C in Comparative Example 1 are all higher than those in Examples 1 and 2, the content of high-value-added target products in Examples 1 and 2 is significantly higher than that in Comparative Example 1. This indicates that although the full-fraction hydrogenation has a higher conversion rate, it also hydrogenates and saturates a large portion of monocyclic aromatic hydrocarbons, naphthalene, and methylnaphthalene, reducing the yield of high-value-added products in the light fraction. Comparative Example 2 did not undergo hydrocracking and directly obtained the target product through distillation. By comparing the yield of each fraction, the content of monocyclic aromatic hydrocarbons in product P1, the content of naphthalene in product P2, and the content of mixed methylnaphthalene in product P3, it can be seen that the yield of monocyclic aromatic hydrocarbons in P1 of Comparative Example 2 is less than that in Examples 1 and 2; while the yields of naphthalene in product P2 and mixed methylnaphthalene in product P3 are not significantly different. This indicates that hydrogenation of the heavy fraction can increase the yield of monocyclic aromatic hydrocarbons without losing the yield of naphthalene and methylnaphthalene.

[0070] Under relatively mild hydrogenation conditions, the ethylene tar conversion rate is low, and the number of aromatic rings saturated by hydrogenation is also low. The reaction depth can be controlled and the product structure adjusted by controlling the hydrocracking reaction conditions.

[0071] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for producing high-value-added products from ethylene cracking tar, characterized in that, Includes the following steps: S1, ethylene tar is fractionated into light fraction L1 and heavy fraction H1 in a pre-fractionation tower, with a cutting temperature of 240~270℃; S2, heavy fraction H1 is mixed with nano-sized oil-soluble metal catalyst and then subjected to hydrocracking reaction to obtain hydrocracking product S1; S3, the hydrocracking product S1 is distilled under atmospheric pressure at a cutting temperature of 240~270℃ to obtain light fraction L2 and bottom heavy fraction S2. S4. The heavy fraction S2 is separated into three fractions by vacuum distillation at a pressure of 10~30 mmHg. The fraction with a temperature of 250~340℃ is the heavy fraction H2; the fraction with a temperature of 340℃~500℃ is the heavy fraction H3; and the fraction with a temperature above 500℃ is the heavy fraction H4. S5, after mixing light fractions L1 and L2, is distilled to obtain crude naphthalene, mixed methyl naphthalene, and raw materials for hydrogenation to produce high aromatic solvent oil; S6, the heavy fraction H2 is hydrorefined to obtain diesel blending components, and the heavy fraction H3 is used as a raw material for the production of mesophase pitch, needle coke and / or carbon black products. Heavy fraction H4 is the external tailings; In step S5, the distillation is carried out in two distillation columns. The top temperature of the first distillation column is 205~210℃, and the top fraction is the feedstock for hydrogenation to produce high aromatic solvent oil. The bottom material enters the second distillation column, which has a top temperature of 210~230℃. The top fraction is crude naphthalene, and the bottom fraction is mixed methyl naphthalene.

2. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, The cutting temperature in step S1 is 250~260℃.

3. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, In step S2, the particle size of the nanoscale oil-soluble metal catalyst is between 3 nm and 50 nm, the reaction temperature is 380 to 430 °C, the pressure is 8 to 16 MPa, and the reaction time is 1 to 3 h.

4. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, In step S2, the active component of the nanoscale oil-soluble metal catalyst is a metal sulfide; the metal is one or more of Mo, Ni, and Co; and the catalyst concentration, based on the metal content, is 100~1000 ppm.

5. The method for producing high-value-added products from ethylene cracking tar according to claim 4, characterized in that, The metal is Mo.

6. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, The cutting temperature in step S3 is 245~255℃.

7. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, The operating pressure for vacuum distillation in step S4 is 15~25 mmHg.

8. The method for producing high-value-added products from ethylene cracking tar according to claim 1, characterized in that, The feedstock obtained in step S5 for the production of high-aromatic solvent oil is produced using a two-stage hydrogenation process. The first stage of the hydrogenation process uses a Ni-based selective hydrogenation catalyst, with a reaction temperature of 30-100℃, a pressure of 1-3 MPa, and a space velocity of 1-3 h⁻¹. -1 The hydrogen-to-oil ratio is 100-400; the two-stage hydrogenation process uses a cobalt-molybdenum-nickel sulfide catalyst, with a reaction temperature of 240-270℃, a pressure of 1-3 MPa, and a space velocity of 1-3 h⁻¹. -1 The hydrogen-to-oil ratio is 300-500.

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