Process for the hydrogenation of ethylene tar

Abstract

The present application relates to the field of ethylene by-product utilization, in particular to a method for hydrogenation of ethylene tar. The method comprises: continuously performing at least two contact reactions with temperature rising in turn between ethylene tar raw material and hydrogen in the presence of a hydrofining catalyst to obtain a hydrofining product; wherein the temperature rising of each contact reaction is 0.5-50 DEG C / time. The present application can directly use the hydrofining product as a high-quality solvent oil blending component by continuously performing at least two contact reactions with temperature rising in turn between ethylene tar raw material and hydrogen, thereby improving the utilization rate. Preferably, the subsequent hydrocracking treatment can maximize the production of benzene (B), toluene (T) and xylene (X), thereby fully utilizing heavy ethylene tar, increasing the added value, realizing the chemical type utilization of ethylene cracking by-product, improving the competitiveness of steam cracking for ethylene, and expanding the new path of BTX production.

Description

Technical Field

[0001] This invention relates to the field of ethylene by-product utilization, and more specifically to a method for hydrogenating ethylene tar. Background Technology

[0002] Ethylene tar, also known as cracked tar, is a high-boiling-point liquid product of the steam cracking process for producing ethylene. It belongs to the diesel fraction (205-360℃) and mainly originates from the bottom of quench oil towers and heavy fuel oil stripping towers. Ethylene tar is a heavy distillate oil rich in aromatics, primarily containing monocyclic heavy aromatics, polycyclic or fused-ring aromatics. Its composition is complex, it readily polymerizes, and it has high contents of gums, heavy metals, and ash, making it unsuitable for direct utilization. The yield of ethylene tar varies depending on the cracking feedstock, generally accounting for about 1 / 5 of the ethylene production. With the increasing use of heavier feedstocks in ethylene production, its yield shows an increasing trend.

[0003] The main uses of ethylene tar include blending gasoline and diesel components, fuel, carbon black production, extraction of naphthalene and methylnaphthalene, and production of aromatic solvent oils. Among these, using it as fuel is the primary utilization of ethylene tar in China, but this method is not only economically inefficient but also produces black smoke and dust during combustion, causing environmental pollution. Carbon black production is the main method of utilizing ethylene tar abroad, offering considerable economic benefits, but domestic technology relies heavily on imports. Domestically developed processes for recovering naphthalene have relatively low yields, and the production of methylnaphthalene suffers from limitations such as small scale, high energy consumption, and low product purity. Hydrogenation of ethylene tar can produce high-value-added BTX aromatics, which can significantly improve the utilization rate of ethylene tar and contribute to the value-added utilization of ethylene byproducts, showing promising market prospects. Foreign companies have already begun using cracked fuel oil to produce aromatic solvent oils, with major producers including ExxonMobil in the United States, Shell in the Netherlands, and Maruzen Oil Company in Japan. Overall, ethylene tar is mainly used for low-value fuel applications. However, with increasingly stringent environmental regulations, the use of untreated, sulfur- and nitrogen-rich, and highly unsaturated ethylene tar fuel will be increasingly restricted, and its future prospects are uncertain.

[0004] Ethylene tar has a high yield (approximately 70%) in the fractions between 205℃ and 300℃, followed by gum and asphaltenes. Ethylene tar also has a high sulfur content, high polycyclic aromatic hydrocarbon content, high density, and short side chains in its aromatic compounds. The initial boiling point (-205℃) fraction mainly consists of indene and its homologues; the 205-225℃ fraction contains naphthalene; the 225-245℃ fraction is mainly methylnaphthalene; the 245-300℃ fraction is mainly dimethylnaphthalene; the 300-360℃ fraction contains large amounts of anthracene, acenaphthene, and phenanthrene; and the substances above 360℃ are mainly gum and asphaltenes with a high carbon-to-hydrogen ratio. Therefore, all fractions of ethylene tar are important raw materials for chemical organic synthesis, from which many valuable chemical products can be extracted, demonstrating significant utilization value.

[0005] In the field of heavy distillate hydrotreating, catalytic cracking feedstock hydrotreating technology has been industrially applied since the 1970s, and has been used in many refineries processing sulfur-containing or high-sulfur crude oil. Currently, mature pretreatment technologies for catalytic cracking feedstocks exist both domestically and internationally, primarily including: UOP's VGO Unionfining and APCU (partial conversion hydrocracking) technologies, and Haldor's... The company's Aroshift technology, Chevron's VGO Hydrotreating technology, Exxon's VGO Hydrodesulfurization technology, IFP's T-star technology, and Mobil, AKZO, and Kellogg's MAKfinging technology, among others, are all examples. Except for T-star, which uses a fluidized bed reaction process, most FCC feedstock hydrotreating pretreatment units employ a fixed bed process. To further improve product quality and conversion rates, catalytic feedstock hydrotreating pretreatment processes are gradually shifting from traditional hydrodesulfurization (HDS) to moderate hydrocracking (MHC) to enhance denitrification, residual carbon, and polycyclic aromatic hydrocarbon saturation capabilities. This approach offers greater operational flexibility and more significant economic benefits.

[0006] CN101724458A discloses a method for hydrogenating ethylene tar. The method involves fractionating ethylene tar into light and heavy components via a fractionation tower. The light fraction is then passed sequentially through a hydrogenation protection catalyst, a hydrogenation refining catalyst, a light fraction hydrogenation decarbonization catalyst, and a hydrocracking catalyst. The heavy components are passed sequentially through a hydrogenation protection catalyst, a hydrogenation decarbonization catalyst, and a hydroconversion catalyst, ultimately yielding gasoline and diesel fractions.

[0007] CN112745949A discloses a method and system for the combined processing of de-oiled bitumen and aromatic-rich distillate oil. In this method, heavy oil is de-asphalted using a solvent. The de-asphalted oil then passes through a hydrotreating reactor I and enters a DCC unit to produce propylene, LCO, and HCO, etc. After the de-oiled bitumen passes through a hydrotreating reactor II, the product is fractionated. The light components enter a hydrorefining reactor to obtain gasoline and diesel fuel components, while the heavy components enter a delayed coking unit to produce coking gasoline, coking diesel, and coking wax oil, etc.

[0008] US5300212A discloses a process for hydrorefining inferior heavy oil. This method involves the conversion of heavy oil feedstock, hydrogen, and catalyst in two reactors. Specifically, the feedstock and a dispersed catalyst with molybdenum phosphate as a precursor first enter a first slurry-bed hydrorefining reactor, where a conversion reaction occurs at 343-482℃ and 0.345-34.5 MPa. The reaction products, after separation, enter a second fluidized bed hydrorefining reactor, where conversion occurs at 343-399℃ and 5.5-27.6 MPa under the action of a supported catalyst. The reaction products then enter a distillation column, yielding a <524℃ fraction and a >524℃ fraction. The <524℃ fraction is taken as the product, while the >524℃ heavy fraction is recycled back to the second reactor. This process can refine inferior heavy oil. However, because the first reactor uses a dispersed catalyst and the second reactor uses a supported catalyst, catalyst particles carried out from the first reactor can easily clog the pores of the heavily supported catalyst in the second reactor or cover the active sites of the catalyst, causing catalyst deactivation and affecting the overall operating cycle.

[0009] CN102134500B discloses a method for extracting naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene from ethylene tar. The method uses ethylene tar containing at least 30% naphthalene and methylnaphthalene as raw material, employing five distillation columns connected in series to sequentially separate naphthalene (>95%), tetramethylnaphthalene, 2-methylnaphthalene (98%), and 1-methylnaphthalene (98%).

[0010] CN109679011B discloses a method for producing copolymerized petroleum resin. This method uses ethylene tar through vacuum distillation and rectification to remove naphthalene, yielding C9-C6 resin. 10 The distillate is mixed with high-purity C5 resin, cresol, and styrene (after removing cyclopentadiene), and polymerized using BF3 as a catalyst. The mixture is then subjected to vacuum distillation, and the distillate is cooled to obtain a copolymerized petroleum resin. This method allows for flexible adjustment of the molecular weight of the petroleum resin by varying the amounts of cresol and styrene, thus enabling the production of petroleum resins with different properties to meet market demands.

[0011] CN113755211A discloses a method for producing needle coke using optimized ethylene tar feedstock. The method involves hydrocracking aromatics, pitch, and gums from ethylene tar. After high-phase, low-phase, and gas-liquid separation, the oil phase is fed into a coking tower to generate needle coke, while the gas phase is recycled to a hydrotreating tower or used as fuel.

[0012] CN1970688B discloses a comprehensive processing technology for ethylene tar. In this process, after the ethylene tar passes through a pre-fractionation tower, the light components are fed into a hydrorefining tower at 260-280°C. The refined products are then fed into four distillation towers connected in series to obtain solvent oil I, refined naphthalene, β-methylnaphthalene, α-methylnaphthalene, mixed methylnaphthalene, and solvent oil II, respectively.

[0013] US20080083649A1 discloses an upgraded utilization of tar. In this invention, ethylene tar is processed in a vacuum tube furnace. The top of the furnace is deasphalted to produce fuel gas, while the bottom of the furnace contains asphaltenes to produce syngas. A portion of the syngas is also fed into a coking unit to produce coking gasoline and diesel. Summary of the Invention

[0014] A comprehensive analysis of the above technologies reveals that existing technologies involve the production of gasoline and diesel fractions, petroleum coke, resins, and solvent oils from low-quality aromatic oils, wasting valuable aromatic resources in these fractions. Based on technologies such as selective hydrorefining and hydrocracking of heavy ethylene tar, optimization and innovation can directly use the refined products as high-quality solvent oil blending components, or maximize the production of benzene (B), toluene (T), and xylene (X). This will fully utilize heavy ethylene tar, increase its added value, achieve chemical utilization of ethylene cracking byproducts, and enhance the competitiveness of steam cracking-based ethylene production.

[0015] The purpose of this invention is to overcome the problems of low added value and serious environmental pollution caused by using heavy ethylene tar as refinery fuel or in the production of solvent oil, gasoline and diesel blending components, etc., in the existing technology. This invention provides a method for hydrogenating ethylene tar, which has the characteristics of diversified products, high added value and low environmental pollution.

[0016] To achieve the above objectives, the present invention provides a method for hydrogenating ethylene tar, the method comprising: in the presence of a hydrorefining catalyst, continuously subjecting ethylene tar feedstock to hydrogen in at least two contact reactions with successively increasing temperatures to obtain a hydrorefined product; wherein the temperature rise of each contact reaction is 0.5-50°C / time.

[0017] Through the above technical solution, the present invention has the following advantages:

[0018] This invention, by subjecting ethylene tar feedstock to at least two consecutive contact reactions with hydrogen at progressively increasing temperatures, enables the direct use of hydrorefined products as high-quality solvent oil blending components, thereby improving utilization. Preferably, combined with subsequent hydrocracking treatment, this invention can maximize the production of benzene (B), toluene (T), and xylene (X), thus fully utilizing heavy ethylene tar, increasing its added value, realizing the chemical utilization of ethylene cracking by-products, enhancing the competitiveness of steam cracking to produce ethylene, and expanding new pathways for BTX production. Attached Figure Description

[0019] Figure 1 These are TEM images of the hydrogenation catalyst after sulfidation in Example 1, where (a) is a TEM image of catalyst A2 after sulfidation and (b) is a TEM image of catalyst A4 after sulfidation.

[0020] Figure 2This is the XRD pattern of the nano-HZSM-11 molecular sieve in Example 1;

[0021] Figure 3 This is the TPR diagram of catalyst C1 in Example 1;

[0022] Figure 4 This is the XRD pattern of the nano-HZSM-5 molecular sieve in Example 14;

[0023] Figure 5 This is the XRD pattern of the micron-sized HZSM-11 molecular sieve in Example 13;

[0024] Figure 6 These are the stability curves of the hydrocracking catalysts in Examples 1 and 14;

[0025] Figure 7 This is a process flow diagram for the hydrogenation of heavy ethylene tar. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] This invention provides a method for hydrogenating ethylene tar, the method comprising: in the presence of a hydrorefining catalyst, continuously subjecting ethylene tar feedstock to hydrogen in at least two contact reactions with successively increasing temperatures to obtain a hydrorefined product; wherein the temperature rise of each contact reaction is 0.5-50℃ / time.

[0028] This invention improves utilization by subjecting ethylene tar feedstock to at least two consecutive contact reactions with hydrogen at progressively higher temperatures, enabling the direct use of the hydrorefined product as a high-quality solvent oil blending component.

[0029] According to a preferred embodiment of the present invention, the objective of the present invention can be achieved as long as the number of temperature-increasing contact reactions is within the aforementioned range, for example, 3, 4, 5, 6, 7, 8, and 9 times, preferably 3 to 5 temperature-increasing contact reactions.

[0030] According to a preferred embodiment of the present invention, the objective of the present invention can be achieved as long as the temperature rise of each contact reaction is within the aforementioned range, for example, it can be 1℃ / time, 3℃ / time, 5℃ / time, 10℃ / time, 15℃ / time, 20℃ / time, 25℃ / time, 30℃ / time, 35℃ / time, 40℃ / time and 45℃ / time, preferably 2-35℃ / time, more preferably 2-35℃ / time.

[0031] To further improve utilization and enhance the hydrorefined product, according to a preferred embodiment of the present invention, the temperature of the hydrorefined product is 30-90°C higher than the temperature of the ethylene tar feedstock, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C and 85°C, preferably 30-80°C, and more preferably 35-80°C.

[0032] According to a preferred embodiment of the present invention, the temperature of the hydrorefined product is 295-370°C, for example, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, and 360°C, preferably 295-325°C. By adopting the aforementioned preferred embodiment, the utilization rate can be further improved, and the hydrorefined product can be improved.

[0033] According to a preferred embodiment of the present invention, the temperature of the ethylene tar feedstock is 200-300°C, for example, 210°C, 220°C, 230°C, 240°C, 260°C, 270°C, 280°C, and 290°C, preferably 215-250°C. By adopting the aforementioned preferred embodiment, the utilization rate can be further improved, and the hydrorefined product can be improved.

[0034] According to a preferred embodiment of the present invention, at least two types of hydrorefining catalysts are sequentially loaded along the material flow direction, and the pore size gradient of the catalysts is reduced. By adopting the aforementioned preferred scheme, the utilization rate can be further improved, and the hydrorefined product can be improved.

[0035] To further improve utilization and enhance the hydrorefined product, according to a preferred embodiment of the present invention, the pore size of adjacent packed catalysts is reduced by 2-25 nm, for example, 3 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm and 20 nm.

[0036] To further improve utilization and improve hydrorefined products, according to a preferred embodiment of the present invention, the packing volume ratio of adjacent packed catalysts is (1-3):(1-3), for example, it can be 1:3, 1:2, 2:3, 1:1, 3:2 and 3:1.

[0037] According to a preferred embodiment of the present invention, the ethylene tar feedstock contains: naphthalene content ≤ 55 wt%; and / or final boiling point ≤ 350 °C; and / or bromine value ≤ 50 gBr / 100 g oil; and / or gum content ≤ 100 mg / 100 ml oil; and / or sulfur content ≤ 600 ppm; and / or nitrogen content ≤ 70 ppm.

[0038] According to a preferred embodiment of the present invention, each of the hydrorefining catalysts is a sulfide-type catalyst, which includes a support and a sulfide supported on the support, wherein the sulfide is a sulfide of the active element and has a tower-like structure. By adopting the aforementioned preferred embodiment, the utilization rate can be further improved and the hydrorefined product can be improved.

[0039] According to a preferred embodiment of the present invention, the number of stacking layers of the tower structure is 3-10 layers, preferably 3-5 layers.

[0040] According to a preferred embodiment of the present invention, the stacking length of the tower structure is 3-12 nm, preferably 3-6 nm.

[0041] According to a preferred embodiment of the present invention, the stacking layer spacing of the tower structure is 0.2-2 nm.

[0042] According to a preferred embodiment of the present invention, the average pore size of the support for the sulfidation catalyst is 7-20 nm.

[0043] According to a preferred embodiment of the present invention, the pore volume of the support for the sulfidation catalyst is 0.5-0.98 cm³. 3 / g.

[0044] According to a preferred embodiment of the present invention, the specific surface area of ​​the support for the sulfidation catalyst is 190-380 m². 2 / g.

[0045] In this invention, the active elements in the sulfidation catalyst include a first active element and a second active element.

[0046] According to a preferred embodiment of the present invention, in the oxidative catalyst before sulfidation of the sulfidation catalyst, the content of the first active element, calculated as oxide, is 50-700 g / L of the support, preferably 60-650 g / L of the support.

[0047] According to a preferred embodiment of the present invention, in the oxidative catalyst before sulfidation of the sulfidation catalyst, the content of the second active element, calculated as oxide, is 5-50 g / L of the support, preferably 5-40 g / L of the support.

[0048] According to a preferred embodiment of the present invention, the first active element comprises a Group VIB metal element and a Group VIII metal element.

[0049] According to a preferred embodiment of the present invention, the second active element comprises a lanthanide metal and / or a Group VA element.

[0050] In this invention, the carrier can be any conventional choice in the art as long as it can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the carrier is selected from at least one of Al2O3, Al2O3-TiO2, Al2O3-TiO2-SiO2, and Al2O3-SiO2, preferably at least one of Al2O3, Al2O3-TiO2, and Al2O3-TiO2-SiO2.

[0051] In this invention, there are no special requirements for the type of Group VIB metal element in the first active element. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Group VIB metal element in the first active element is selected from at least one of Mo, W and Cr, preferably Mo and / or W.

[0052] In this invention, there are no special requirements for the type of Group VIII metal element in the first active element. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Group VIII metal element in the first active element is selected from at least one of Ni, Co, Fe, Pt and Pd.

[0053] In this invention, there are no special requirements for the type of lanthanide metal element in the second active element. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the lanthanide metal element in the second active element is selected from La and / or Ce.

[0054] In this invention, there are no special requirements for the type of Group VA element in the second active element. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Group VA element in the second active element is selected from P and / or Sb, preferably P.

[0055] In this invention, there are no special requirements for the preparation method of the hydrorefining catalyst. For example, it can be impregnation, co-precipitation, ion exchange, or supercritical fluid drying. This invention provides a method for preparing a hydrorefining catalyst that enables the active component elements to be distributed in a tower-like manner on the surface of the support after sulfidation, achieving a better hydrorefining effect. The preparation method includes: mixing an active element source, a support, a chelating surfactant, and a water-soluble additive to obtain a mixture, impregnation, curing, first drying, first calcination, and sulfidation.

[0056] The impregnation solution (mixture) of this invention has a high metal concentration, weak interaction between the active component and the carrier, and low viscosity. After subsequent curing, drying, calcination, and sulfidation, the active metal of the catalyst has a tower-shaped structure, with active sites such as edges, corners, and sides fully exposed. It has good hydrogenation activity of polycyclic aromatic hydrocarbons, high desulfurization and denitrification rates, and can be used under relatively mild conditions with a long service life.

[0057] According to a preferred embodiment of the present invention, before the contact reaction, the ethylene tar feedstock and hydrogen are first contacted with a protective agent for pre-reaction. The protective agent includes a hydrogenated active metal oxide and an oxide carrier, and the content of the hydrogenated active metal oxide in the protective agent is 5-60 g / L of the carrier.

[0058] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the ratio of the packing volume of the protective agent to the total packing volume of the hydrorefining catalyst. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the ratio of the packing volume of the protective agent to the total packing volume of the hydrorefining catalyst is 1:4-25, preferably 1:4-10.

[0059] According to a preferred embodiment of the present invention, the temperature of the pre-reaction is not higher than the temperature of the first contact reaction.

[0060] In this invention, the temperature of the pre-reaction is a conventional choice in the art, as illustrated below, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the temperature of the pre-reaction is 200-290°C.

[0061] In this invention, the pressure of the pre-reaction is a conventional choice in the art, as illustrated below, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the pressure of the pre-reaction is 2.0-8.0 MPa.

[0062] In this invention, the hydrogen-to-oil volume ratio of the pre-reaction is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the hydrogen-to-oil volume ratio of the pre-reaction is 400-3000.

[0063] In this invention, the liquid phase volume hourly space velocity (LHSV) of the pre-reaction is conventionally chosen in the art, as illustrated below, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the LHSV of the pre-reaction is 0.2-3 h⁻¹. -1 .

[0064] According to a preferred embodiment of the present invention, the average pore size of the protective agent is 20-30 nm.

[0065] According to a preferred embodiment of the present invention, the pore volume of the protective agent is 0.5-0.98 cm³. 3 / g.

[0066] According to a preferred embodiment of the present invention, the specific surface area of ​​the protective agent is 200-240 m². 2 / g.

[0067] In this invention, the hydrogenated active metal in the protective agent is selected from at least one of Ni, Mo, W and Co.

[0068] In this invention, the oxide carrier in the protective agent is Al2O3.

[0069] In this invention, no special requirements are made for the preparation method of the protective agent. The following is an exemplary preparation method, which includes: mixing a carrier, a hydrogenated active metal source and a chelating surfactant, followed by drying and calcination to obtain the protective agent.

[0070] In this invention, the temperature of the contact reaction is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the temperature of the contact reaction is 200-300°C, preferably 215-250°C.

[0071] In this invention, the pressure of the contact reaction is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the pressure of the contact reaction is 2.0-8.0 MPa, preferably 2.2-6.0 MPa.

[0072] In this invention, the hydrogen-to-oil volume ratio of the contact reaction is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the hydrogen-to-oil volume ratio of the contact reaction is 400-3000, preferably 600-2000.

[0073] In this invention, the liquid hourly space velocity (LHSV) of the contact reaction is a conventional choice in the art, as illustrated below, but not to limit the scope of the invention. According to a preferred embodiment of the invention, the LHSV of the contact reaction is 0.2-3 h⁻¹.-1 Preferably 0.6-1.2h -1 .

[0074] According to a preferred embodiment of the present invention, the method further includes: sequentially purifying and hydrocracking the hydrorefined product. By adopting the aforementioned preferred scheme, combining hydrorefining and hydrocracking, the production of benzene (B), toluene (T), and xylene (X) can be maximized, thereby fully utilizing heavy ethylene tar, increasing its added value, realizing the chemical utilization of ethylene cracking by-products, enhancing the competitiveness of steam cracking to produce ethylene, and expanding new pathways for BTX production.

[0075] According to a preferred embodiment of the present invention, controlling the conversion rate of naphthalene to ≥98.5 wt% and / or the selectivity of tetrahydronaphthalene to ≥98.5 wt% during the contact reaction process is more beneficial to the production of BTX.

[0076] According to a preferred embodiment of the present invention, after purification treatment of the hydrogenated product, the sulfur content is ≤1ppm, preferably ≤0.85ppm.

[0077] According to a preferred embodiment of the present invention, the nitrogen content of the hydrogenated product after purification is ≤1ppm, preferably ≤0.8ppm.

[0078] According to a preferred embodiment of the present invention, the unreacted hydrogen gas after the contact reaction is completed is divided into two parts and recycled back to the contact reaction process. One part of the hydrogen gas is mixed with fresh raw materials and heated before being recycled back to the contact reaction process; the other part of the hydrogen gas is directly recycled back to the contact reaction process. Preferably, the volume ratio of the other part of the hydrogen gas to the hydrogen gas in the fresh raw materials is 0.1-0.5, more preferably 0.2-0.3.

[0079] According to a preferred embodiment of the present invention, at least a portion of the unreacted hydrogen gas after the hydrocracking process is completed is recycled back into the hydrocracking process.

[0080] According to a preferred embodiment of the present invention, the purified stream of the hydrorefined product is 0-99 wt%, for example 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, and 85 wt%, preferably 10-50 wt%, recycled back to the contact reaction process. By adopting the aforementioned preferred embodiment, the utilization rate can be further improved, and the hydrorefined product can be improved.

[0081] According to a preferred embodiment of the present invention, at least a portion of the heavy aromatics in the hydrocracking products of the hydrocracking process are recycled back into the ethylene tar feedstock.

[0082] In this invention, the temperature of the hydrocracking treatment is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the temperature of the hydrocracking treatment is 260-500°C, preferably 260-480°C.

[0083] In this invention, the pressure of the hydrocracking treatment is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the pressure of the hydrocracking treatment is 2.0-8.0 MPa, preferably 3.0-6.5 MPa.

[0084] In this invention, the hydrogen-to-oil volume ratio of the hydrocracking treatment is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the hydrogen-to-oil volume ratio of the hydrocracking treatment is 400-3000, preferably 600-2000.

[0085] In this invention, the liquid phase volume hourly space velocity (LHSV) of the hydrocracking treatment is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the LHSV of the hydrocracking treatment is 0.2-3 h⁻¹. -1 Preferably 0.6-1.2h -1 .

[0086] In this invention, the hydrocracking process uses a hydrocracking catalyst, and the TPR hydrogen atmosphere reduction temperature of the hydrocracking catalyst is below 400°C, preferably 350-390°C.

[0087] In this invention, the hydrocracking catalyst comprises a Group VIII metal element, optionally a lanthanide metal element, optionally a Group IVB metal element, and a molecular sieve support.

[0088] According to a preferred embodiment of the present invention, the Brønsted acid / Lylene acid ratio of the molecular sieve support is 0.5-12, preferably 1.5-7.3.

[0089] According to a preferred embodiment of the present invention, the particle size of the molecular sieve carrier is ≤1000nm, preferably 100-500nm.

[0090] According to a preferred embodiment of the present invention, the pore size of the molecular sieve support is 5-10 nm.

[0091] According to a preferred embodiment of the present invention, the pore volume of the molecular sieve support is 0.2-0.3 cm³. 3 / g.

[0092] According to a preferred embodiment of the present invention, the specific surface area of ​​the molecular sieve support is ≥250 m². 2 ·g -1 Preferably 250-400m 2 ·g -1 .

[0093] According to a preferred embodiment of the present invention, the SiO2 / Al2O3 molar ratio of the molecular sieve support is 10-200, preferably 15-60.

[0094] According to a preferred embodiment of the present invention, the dispersion of Group VIII metal elements in the hydrocracking catalyst is greater than 8%, preferably 8-15%.

[0095] In this invention, the Group VIII metal element is a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Group VIII metal element is selected from at least one of Ni, Pt, and Pd, preferably Ni and / or Pt.

[0096] In this invention, the lanthanide metal elements are conventional choices in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the lanthanide metal elements are selected from Ce and / or La, preferably Ce.

[0097] In this invention, the Group IVB metal elements are conventional choices in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Group IVB metal elements are selected from Zr and / or Ti, preferably Zr.

[0098] According to a preferred embodiment of the present invention, the content of Group VIII metal elements in the hydrocracking catalyst, calculated as oxides, is 50-260 g / L of the support, preferably 50-150 g / L of the support.

[0099] According to a preferred embodiment of the present invention, the content of lanthanide metal elements in the hydrocracking catalyst, calculated as oxides, is 0.1-100 g / L of the support, preferably 0.1-50 g / L of the support.

[0100] According to a preferred embodiment of the present invention, the oxide content of Group IVB metal elements in the hydrocracking catalyst is 0.1-100 g / L of the support, preferably 0.1-50 g / L of the support.

[0101] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the type of molecular sieve carrier. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the molecular sieve carrier includes at least one of nano HZSM-5 molecular sieve, nano HMor molecular sieve, nano HZSM-11 molecular sieve, nano HUSY molecular sieve, nano Hβ molecular sieve, nano HMCM-22 molecular sieve and nano HMCM-41 molecular sieve, preferably nano HZSM-11 molecular sieve.

[0102] In this invention, as long as a hydrocracking catalyst with the aforementioned characteristics of this invention can be prepared, there are no special requirements for the preparation method of the hydrocracking catalyst. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation method of the hydrocracking catalyst in this invention includes: uniformly mixing a Group VIII metal element source, optionally a lanthanide metal element source, and optionally a Group IVB metal element source, loading the mixture on a molecular sieve support, first drying, and first calcination.

[0103] The present invention will be described in detail below through embodiments. In the following embodiments,

[0104] The structural characteristics of the catalyst and the size of the metal nanoparticles were measured using a G2F30 transmission electron microscope (TEM) from FEI Corporation, USA.

[0105] The elemental composition of the catalyst was determined using a Rigaku ZSX-100e 4580 X-ray fluorescence spectrometer.

[0106] Nitrogen and sulfur tests were performed on an Antek 900 sulfur-nitrogen analyzer. The nitrogen content test method referenced standard SH / T0657-2007 (chemiluminescence method), and the sulfur content test method referenced standard SH / T0689-2000 (ultraviolet fluorescence method).

[0107] XRD patterns were obtained using a Bruker D8 Advance X-ray diffractometer (Germany) for phase analysis of the catalyst samples. Specific parameters were: operating voltage 30kV, current 30mA, and scanning range 0°-80°.

[0108] H2-TPR spectral analysis was performed using an AutoChem 2920 dynamic adsorption instrument from Micron Instruments, USA. The reducing gas was a 10% H2-Ar mixture by volume. The sample mass was 50 mg, the gas flow rate was 50 ml / min, and the temperature was increased from room temperature to 800 °C at a rate of 10 °C / min.

[0109] NH3-TPD was measured using an Altamira AMI-3300 chemisorption analyzer from Micron Instruments, Inc., USA.

[0110] The pore structure parameters of the molecular sieve support were measured using a Micrometrics Tristar 3000 surface area analyzer at a test temperature of -196℃. Before the test, the sample was vacuum activated at 300℃ for 6 hours.

[0111] In this invention, the method for testing the dispersibility of the active group Ni is as follows:

[0112] R = [Ni] / [Ni] 总 *100%=(2 / 3×V0×N) A / 22400) / (WPN A / M)*100%

[0113] In the formula:

[0114] R-----Dispersion degree of Ni;

[0115] [Ni] ----- Number of nickel atoms on the surface;

[0116] [Ni] 总 -----Total number of nickel atoms;

[0117] V0-----Titration volume of hydrogen, mL;

[0118] N A -----Avogadro's constant (6.02) × 10 23 ;

[0119] W-----Sample mass, g;

[0120] P-----Mass fraction of nickel in the sample, %;

[0121] M ----- The atomic weight of nickel is 58.7.

[0122] The naphthalene conversion rate and tetrahydronaphthalene selectivity in the product are calculated using the following formula:

[0123]

[0124]

[0125] In the following embodiments,

[0126] Unless otherwise specified, "%" refers to mass percentage, all pressures are gauge pressures, and all raw materials are commercially available products.

[0127] Unless otherwise specified, the evaluation methods for hydrogenation of heavy ethylene tar include:

[0128] Feedstock for hydrogenation refining of heavy ethylene tar: heavy ethylene tar, with a naphthalene content of 50 wt% in solution and / or a final boiling point of 350℃; and / or gum content of 98 mg / 100g oil; sulfur content of 500 ppm; nitrogen content of 60 ppm; and bromine value of 48 mgBr / 100g oil.

[0129] Evaluation criteria:

[0130] Hydrorefining: Liquid hourly space velocity 0.8 h⁻¹ -1 Pressure 6.0 MPa, H2 / Oil (v / v) = 1200; and / or the mass ratio of refined product recycling to raw material stream before refining is 0-2;

[0131] Hydrocracking: Temperature 400℃, Liquid hourly space velocity 0.8h -1 Pressure 4.0 MPa, H2 / Oil(v / v) = 600.

[0132] Example 1

[0133] 1. Preparation of hydrorefining catalyst

[0134] 1000g of Al2O3 support (pore size: 13nm) and Al2O3-TiO2-SiO2 support (pore size: 11nm, of which Al2O3 is 97%, TiO2 is 1.5% and SiO2 is 1.5%) were respectively mixed with 0.85L of a mixed solution containing nickel acetate, lanthanum nitrate, ammonium molybdate, 1,2-cyclohexanediaminetetraacetic acid, citric acid, phosphoric acid, ethylene glycol and acetone (containing 83g NiO, 440g MoO3, 5g La2O3 and 10g P2O5). The amount of 1,2-cyclohexanediaminetetraacetic acid was 5.5% of the mass of the mixed solution, the amount of citric acid was 2.5% of the mass of the mixed solution, the amount of ethylene glycol was 2.5% of the mass of the mixed solution, and the amount of acetone was 0.5% of the mass of the mixed solution. After impregnation, the catalysts were cured at 25°C for 24 hours, dried at 110°C for 6 hours, and calcined at 450°C for 4 hours to obtain catalysts A1 and A2, respectively. The structural parameters of the carrier are shown in Table 3.

[0135] 1000g of Al2O3-SiO2 support (pore size: 9nm, of which Al2O3 is 95% and SiO2 is 5%) was mixed with 0.85L of a mixed solution containing cobalt acetate, lanthanum nitrate, ammonium molybdate, 1,2-cyclohexanediaminetetraacetic acid, citric acid, phosphoric acid, ethylene glycol, and acetone (containing 83g CoO, 440g MoO3, 5g La2O3, and 10g P2O5). The amounts of 1,2-cyclohexanediaminetetraacetic acid, citric acid, ethylene glycol, and acetone were 5.5% and 2.5% of the total mass of the mixed solution, respectively. After impregnation, the mixture was cured at 25℃ for 24 hours, dried at 110℃ for 6 hours, and calcined at 450℃ for 4 hours to obtain catalyst A3. The structural parameters of the support are shown in Table 3.

[0136] Catalysts A1 and A2 contain 83 g / L NiO, 440 g / L MoO3, 5 g / L La2O3, and 10 g / L P2O5, while catalyst A3 contains 83 g / L CoO, 440 g / L MoO3, 5 g / L La2O3, and 10 g / L P2O5.

[0137] 2. Preparation of Protective Agent

[0138] 1 L of Al₂O₃ support (pore size: 28 nm) was mixed with 0.75 L of a mixed solution of ammonium molybdate, nickel acetate, lanthanum nitrate, 1,2-cyclohexanediaminetetraacetic acid, citric acid, and phosphoric acid (containing 11 g NiO, 49 g MoO₃, 5 g La₂O₃, 25 g 1,2-cyclohexanediaminetetraacetic acid, and 5 g P₂O₅). The amount of 1,2-cyclohexanediaminetetraacetic acid was 1.8% of the mass of the mixed solution. The mixture was dried at 110 °C for 6 hours and calcined at 450 °C for 4 hours to prepare protective agent B1. Protective agent B1 has a pore size of 28 nm and a pore volume of 0.94 cm⁻¹. 3 / g, specific surface area 213m² 2 / g.

[0139] Protective agent B1 contains 11 g / L NiO, 49 g / L MoO3, 5 g / L La2O3, and 5 g / L P2O5.

[0140] 3. Preparation of hydrocracking catalyst

[0141] Sodium aluminate aqueous solution and tetrabutylammonium hydroxide aqueous solution are slowly added to water glass in a certain proportion under stirring. The pH of the solution is adjusted to 11 with acetic acid, so that the molar ratio in the mixed solution is: n(Na2O):n(Al2O3):n(CH3COOH):n(SiO2):n(TBA). +The ratio of H2O to n(H2O) is 2:1:0.8:25:2:500. Nano-ZSM-11 molecular sieves were synthesized under dynamic crystallization conditions at 125℃, 90h, and 150rpm. After crystallization, the sieve was filtered, washed, and dried at 120℃ to obtain zeolite powder. Each gram of zeolite powder was subjected to ion exchange three times in 10ml of 0.8mol / L NH4NO3 solution at 80℃ for 1h each time, converting it to the ammonia form. The powder was then dried at 120℃ for 8h and calcined at 550℃ for 5h to obtain nano-HZSM-11 molecular sieves. The sieves were then pressed into tablets, crushed, and sieved, with 20-mesh nano-HZSM-11 molecular sieves used for later use.

[0142] Take the formed nano-HZSM-11 molecular sieve (SiO2 / Al2O3 molar ratio 25, pore size 5.06nm, specific surface area 388m²) 2 ·g -1 A mixture of 1L of Brønsted acid (B acid / L acid ratio of 2.1%) and nickel acetate, nickel nitrate, basic nickel carbonate, cerium nitrate, zirconium nitrate, and 1,2-cyclohexanediaminetetraacetic acid (containing 108g NiO, 8g CeO2, 6g ZrO2, and 48g 1,2-cyclohexanediaminetetraacetic acid) was prepared, with the 1,2-cyclohexanediaminetetraacetic acid accounting for 7.5% of the mass of the mixed solution. The mixture was dried at 110℃ for 6 hours and calcined at 450℃ for 4 hours to prepare catalyst C1. The TPR hydrogen atmosphere reduction temperature of catalyst C1 was measured to be 372℃. Figure 3 As shown.

[0143] XRD pattern of nano HZSM-11 molecular sieve is shown below Figure 2 The hole structure parameters are shown in Table 3.

[0144] Catalyst C1 contains 108 g / L NiO, 8 g / L CeO2, and 6 g / L ZrO2.

[0145] 3. Loading of hydrorefining catalyst and protective agent

[0146] Catalysts A3, A2, A1, and B1 are loaded sequentially from bottom to top, with a catalyst volume ratio of 2:2:4:2, and are then loaded into the adiabatic bed reactor (hydrogenation refining reactor, the same below).

[0147] 4. Hydrorefining catalyst sulfidation

[0148] After the airtightness is verified, sulfidation begins. The system pressure is 5.5 MPa, and the hydrogen volume hourly space velocity is 800 h⁻¹. -1 Hydrogen gas was introduced, and the temperature was increased from room temperature to 150°C at a rate of 30°C / h, with a volume hourly space velocity (VHSV) of 1 h⁻¹. -1A sulfurizing agent containing 0.5 wt% sulfur was introduced, and the temperature was increased to 180°C at a rate of 5°C / h for 6 hours, held for 5 hours, then increased to 230°C at a rate of 5°C / h for 10 hours, held for 4 hours, then increased to 280°C at a rate of 10°C / h for 5 hours, held for 4 hours, then increased to 320°C at a rate of 10°C / h for 4 hours, and held for 2 hours to complete the catalyst sulfidation. The sulfidated A2 catalyst was tested using a G2F30 transmission electron microscope (TEM) from FEI Corporation, USA. Figure 1 (a) As can be seen from the figure, the active phase of the sulfidation catalyst has a tower-shaped structure with 3-5 stacked layers; the stacking layer spacing is 0.2-2 nm; and the stacking length is 3-6 nm.

[0149] 5. Hydrocracking catalyst loading and reduction

[0150] C1 was loaded into an adiabatic bed reactor (hydrocracking reactor, the same below), heated from room temperature to 500℃ at a rate of 20℃ / h, and kept at a constant temperature for 3 hours under a hydrogen atmosphere at a hydrogen gas rate of 500ml / min.

[0151] 6. Catalyst Evaluation

[0152] Heavy ethylene tar is mixed with fresh hydrogen and hydrorefining recycle hydrogen, heated by a heater, and then fed into the hydrorefining reactor. The hydrorefining product enters the high-precision tank, and the hydrogen from the high-precision tank outlet enters the hydrorefining compressor. After compression, it is divided into two parts: hydrorefining recycle hydrogen and cold hydrogen. The recycle hydrogen is mixed with the feedstock, heated, and then fed into the hydrorefining reactor, while the cold hydrogen is directly fed into the hydrorefining reactor. The liquid phase from the high-precision tank outlet enters the oil-water separator for the refined product. After dehydration, the oil phase enters the low-precision tank and the stripping tower. After H2S is removed from the oil phase by the stripping tower, the purified product circulation rate is 0.5 times the mass ratio of the second-stage liquid phase feed. The purified product is heated by the hydrocracking heater and then fed into the hydrocracking reactor. The cracking product enters the hydrocracking high-precision tank, and the hydrogen enters the hydrocracking compressor for circulation. The liquid phase passes through the third-stage low-precision tank and then enters the distillation column for fractionation to obtain ethylene cracking feedstock, BTX, and heavy aromatics.

[0153] The temperature of the hydrorefining feedstock stream is 225℃, the temperature of the hydrorefining product stream is 305℃, and the volume ratio of cold hydrogen to hydrorefining inlet hydrogen is 0.2.

[0154] Along the flow direction, the ratio of the time for the material to contact and react with the protective agent B1 and catalysts A1, A2, and A3 in sequence is 2:2:4:2; the temperature rises of the contact reactions are 35℃, 20℃, 23℃, and 2℃, respectively.

[0155] The evaluation results are listed in Table 1 (refining) and Table 2 (cracking).

[0156] Example 2

[0157] Same as Example 1, except that A2 is replaced with A4, and the preparation of the hydrorefining catalyst A4 is as follows:

[0158] 1 L of Al2O3-SiO2 support (pore size: 11 nm, Al2O3 91%, SiO2 9%) was mixed with 0.75 L of a mixed solution of nickel acetate, ammonium metatungstate, lanthanum nitrate, ammonium molybdate, 1,2-cyclohexanediaminetetraacetic acid, urea, ethanol, and phosphoric acid (containing 40 g NiO, 60 g MoO3, 5 g La2O3, 165 g WO3, 129 g total of 1,2-cyclohexanediaminetetraacetic acid, urea, and ethanol, and 10 g P2O5). The amounts of 1,2-cyclohexanediaminetetraacetic acid, citric acid, ethylene glycol, and acetone were 5.5% and 2.5% of the total mass of the mixed solution, respectively. After impregnation, the mixture was cured at 25 °C for 24 hours, dried at 110 °C for 6 hours, and calcined at 450 °C for 4 hours to prepare catalyst A4. The TEM image of A4 is shown in 1b. It can be seen from the image that the active phase of the sulfide catalyst has a tower-shaped structure with 3-5 stacked layers; the stacking layer spacing is 0.2-2 nm; and the stacking length is 3-6 nm.

[0159] The A4 catalyst contains 40 g / L NiO, 60 g / L MoO3, 165 g / L WO3, 5 g / L La2O3, and 10 g / L P2O5. The structural parameters of the support are shown in Table 3.

[0160] The temperature of the hydrorefining feedstock stream is 250℃, the temperature of the hydrorefining product stream is 295℃, and the volume ratio of cold hydrogen to hydrorefining inlet hydrogen is 0.3.

[0161] The evaluation results are listed in Table 1 (refining) and Table 2 (cracking).

[0162] Example 3

[0163] Similar to Example 1, except that the temperature of the hydrorefining feedstock stream is 225°C, the temperature of the hydrorefining product stream is 295°C, and the volume ratio of cold hydrogen to hydrorefining inlet hydrogen is 0.25.

[0164] Along the flow direction, the ratio of the time for the material to contact and react with the protective agent B1 and the catalysts A1, A2 and A3 in sequence is 2:2:4:2; the temperature rises of the contact reactions are 30℃, 18℃, 20℃ and 2℃, respectively.

[0165] The evaluation results are listed in Table 1 (refining) and Table 2 (cracking).

[0166] Example 4

[0167] Similar to Example 1, except that A3, A2, and B1 are loaded sequentially from bottom to top, with a catalyst volume ratio of 2:6:2;

[0168] The temperature of the hydrorefining feedstock stream is 225℃, and the temperature of the hydrorefining product stream is 305℃.

[0169] Along the flow direction, the ratio of the time for the material to contact and react with the protective agent B1 and catalysts A2 and A3 in sequence is 2:6:2; the temperature rise of the contact reaction is 48℃, 30℃, and 2℃, respectively.

[0170] The evaluation results are listed in Table 1 (refining) and Table 2 (cracking).

[0171] Example 5

[0172] According to Example 1, except that no protective agent is used, that is, A3, A2, A1 are loaded sequentially from bottom to top, with a catalyst volume ratio of 2.5:2.5:5;

[0173] The temperature of the hydrorefining feedstock stream is 225℃, and the temperature of the hydrorefining product stream is 305℃.

[0174] Along the flow direction, the ratio of the time for the material to contact and react with catalysts A1, A2, and A3 in sequence is 2.5:2.5:5; the temperature rises of the contact reactions are 35℃, 30℃, and 15℃, respectively.

[0175] The evaluation results are listed in Table 1 (refining) and Table 2 (cracking).

[0176] Example 6

[0177] According to Example 1, the difference is that the temperature of the hydrorefining feedstock stream is 225°C, and the temperature of the hydrorefining product stream is 283°C; the temperature rise of the contact reaction is 15°C, 16°C, 25°C, and 2°C, respectively.

[0178] The catalyst evaluation results are shown in Table 1 (hydropurification) and Table 2 (hydrocracking).

[0179] Example 7

[0180] According to Example 1, the difference is that the temperature rise of the contact reaction is 28°C, 10°C, 40°C and 2°C respectively. The catalyst evaluation results are shown in Table 1 (hydropurification) and Table 2 (hydrocracking).

[0181] Example 8

[0182] According to Example 1, the difference is that the temperature of the hydrorefined product is 88°C higher than the temperature of the ethylene tar feedstock, that is, the temperature of the hydrorefined product stream is 313°C; the temperature rise of the contact reaction is 43°C, 20°C, 23°C and 2°C respectively.

[0183] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0184] Example 9

[0185] According to Example 1, the difference is that A3, A1, A2, and B1 are loaded sequentially from bottom to top.

[0186] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0187] Example 10

[0188] The difference from Example 1 is that the naphthalene content in the ethylene tar feedstock is 58 wt%.

[0189] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0190] Example 11

[0191] According to Example 1, the difference is that the temperature of the hydrorefining feedstock stream is 260°C; the temperature rise of the contact reaction is 25°C, 15°C, 18°C, and 2°C, respectively.

[0192] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0193] Example 12

[0194] According to Example 1, the difference is that 80% of the purified stream of the hydrorefined product is recycled back to the hydrorefined feedstock.

[0195] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0196] Example 13

[0197] According to Example 1, except that C1 is replaced with C2, the preparation of catalyst C2 for hydrocracking is as follows:

[0198] The pre-formed micron-sized HZSM-11 (SiO2 / Al2O3 molar ratio 25, Brønsted acid / Low acid ratio 2.3, pore size 5nm, specific surface area 324m²) was used. 2 ·g -1 1 L of NiO was mixed with a mixed solution of nickel acetate, nickel nitrate, basic nickel carbonate, cerium nitrate, zirconium nitrate, and 1,2-cyclohexanediaminetetraacetic acid (containing 108 g NiO, 8 g CeO2, 6 g ZrO2, and 48 g 1,2-cyclohexanediaminetetraacetic acid), wherein the amount of 1,2-cyclohexanediaminetetraacetic acid was 7.5% of the mass of the mixed solution. The mixture was dried at 110 °C for 6 hours and calcined at 450 °C for 4 hours to prepare catalyst C2.

[0199] XRD pattern of micron-sized HZSM-11 molecular sieve (see below) Figure 5The hole structure parameters are shown in Table 3.

[0200] Catalyst C2 contains 108 g / L NiO, 8 g / L CeO2, and 6 g / L ZrO2.

[0201] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0202] Example 14

[0203] Same as Example 1, except that C1 is replaced with C3. Preparation of hydrocracking catalyst C3:

[0204] The pre-formed nano-HZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio 25, Brønsted acid / Low acid ratio 2, pore size 5.1 nm, specific surface area 384 m²) was used. 2 ·g -1 1 L of NiO was mixed with a mixed solution of nickel acetate, nickel nitrate, basic nickel carbonate, cerium nitrate, zirconium nitrate, and 1,2-cyclohexanediaminetetraacetic acid (containing 108 g NiO, 8 g CeO2, 6 g ZrO2, and 48 g 1,2-cyclohexanediaminetetraacetic acid), wherein the amount of 1,2-cyclohexanediaminetetraacetic acid was 7.5% of the mass of the mixed solution. The mixture was dried at 110 °C for 6 hours and calcined at 450 °C for 4 hours to prepare catalyst C3.

[0205] The pore structure parameters of the nano HZSM-5 molecular sieve are shown in Table 3.

[0206] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0207] Example 15

[0208] Same as Example 1, except that A1 is replaced with A5, A2 is replaced with A6, and A3 is replaced with A7.

[0209] 1. Preparation of hydrorefining catalyst

[0210] 1 L of support (pore size: 13 nm, Al2O3 100%) was mixed with 0.75 L of a mixed solution of nickel nitrate, ammonium molybdate, urea, citric acid, water, and phosphoric acid (containing 83 g NiO, 440 g MoO3, 129 g total of citric acid and urea, and 10 g P2O5). After impregnation, the mixture was dried at 110 °C for 6 hours and calcined at 480 °C for 4 hours to prepare catalyst A5. The structural parameters of the support are shown in Table 3.

[0211] 1 L of a support (pore size: 11 nm, Al₂O₃ 95%, SiO₂ 5%) was mixed with 0.75 L of a mixed solution of nickel nitrate, ammonium molybdate, urea, citric acid, water, and phosphoric acid (containing 83 g NiO, 440 g MoO₃, 129 g total of citric acid and urea, and 10 g P₂O₅). After impregnation, the mixture was dried at 110 °C for 6 hours and calcined at 480 °C for 4 hours to prepare catalyst A6. The structural parameters of the support are shown in Table 3.

[0212] 1 L of a support (pore size: 9 nm, Al₂O₃ 95%, SiO₂ 5%) was mixed with 0.78 L of a mixed solution of cobalt nitrate, ammonium molybdate, urea, citric acid, water, and phosphoric acid (containing 83 g CoO, 440 g MoO₃, 129 g total of citric acid and urea, and 10 g P₂O₅). After impregnation, the mixture was dried at 110 °C for 6 hours and calcined at 480 °C for 4 hours to prepare catalyst A7. The structural parameters of the support are shown in Table 3.

[0213] 3. Loading of hydrorefining catalyst and protective agent

[0214] Catalysts A7 (9 nm pore size), A6 (11 nm pore size), A5 (13 nm pore size), and B1 were sequentially loaded into the adiabatic bed reactor (hydrogenation refining reactor, hereinafter the same) from bottom to top in a volume ratio of 2:2:4:2.

[0215] 4. Hydrorefining catalyst sulfidation

[0216] After the airtightness is verified, sulfidation begins. The system pressure is 3.5 MPa, and the hydrogen volume hourly space velocity is 800 h⁻¹. -1 Hydrogen gas was introduced, and the temperature was increased from room temperature to 150°C at a rate of 30°C / h, with a volume hourly space velocity (VHSV) of 1 h⁻¹. -1 A vulcanizing agent containing 0.5 wt% sulfur is introduced, and the temperature is increased to 230℃ at 10℃ / h for 8 hours. After holding at this temperature for 4 hours, the temperature is increased to 280℃ at 20℃ / h for 2.5 hours. After holding at this temperature for 2 hours, the temperature is increased to 320℃ at 20℃ / h for 4 hours. After holding at this temperature for 2 hours, the catalytic vulcanization is complete.

[0217] After sulfidation, A5, A6, and A7 have a lamellar structure with an edge length of 10–30 nm, and the distribution of sulfides is extremely uneven, with agglomeration.

[0218] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0219] Example 16

[0220] Same as Example 1, except that: each layer of hydrorefining catalyst is A8;

[0221] Preparation of A8:

[0222] Solution A: Nickel nitrate (calculated as NiO) is 0.60 mol / L, and aluminum chloride (calculated as Al₂O₃) is 0.38 mol / L. Solution B: Sodium tungstate is 0.30 mol / L, and sodium molybdate is 0.75 mol / L. Solution C: Sodium aluminate is 0.10 mol / L (calculated as Al₂O₃). Divide Solution C into four equal portions. Heat Solution A to 70°C. Add Solution B and sodium hydroxide solution (pH = 13.8) to Solution A in parallel streams for co-precipitation. Control the reaction pH at 6.2–6.3, the reaction temperature at 70°C, and the reaction time at 60 min. The catalyst underwent aging treatment at 83℃. First, the pH was adjusted to 13.5 using sodium aluminate solution for 0.3 hours. Then, one part of solution C was added, and the pH was adjusted to 10.0 for 0.4 hours. Next, the pH was adjusted to 6.4 for 0.2 hours. This complete process of adding one part of solution C was repeated four times until all solution C was added. The amount of Al added during the aging process, calculated as Al2O3, accounted for 25.0% of the final catalyst Al2O3 composition, ultimately yielding slurry D. Slurry D was vacuum filtered to obtain a filter cake. The filter cake underwent a single conditioning process directly in a vacuum filter at 37℃ for 5.0 hours, resulting in a cake thickness of 22%. Deionized water at a mass ratio of 4:1 (to the catalyst preparation) was added to the top of the filter cake at 37℃. After 1 minute, vacuum filtration was performed until no filtrate dripped from the filter cake. The filter cake was further cured a second time at 65℃ for 1.2 hours, until the cake content was 28%. Deionized water (2:1 mass ratio to catalyst preparation) was added to the top layer of the filter cake at 65℃ for 2 minutes. Vacuum filtration was then performed until no filtrate dripped from the filter cake. Filter cake F was obtained after washing. Filter cake F was dried at 72℃ to a dry basis of 48%. It was then extruded, dried at 110℃ for 6 hours, and calcined at 510℃ for 4 hours to obtain the final catalyst A8. Its main properties are shown in Table 3.

[0223] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0224] Comparative Example 1

[0225] Same as Example 1, except that the refining catalyst is only filled with A1 and B1, and a single hydrogenation refining occurs in the presence of A1.

[0226] The temperature of the hydrorefining feedstock stream is 225℃, and the temperature of the hydrorefining product stream is 315℃.

[0227] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0228] Comparative Example 2

[0229] Similar to Example 1, except that the temperature of the hydrorefining feedstock stream is 215°C and the temperature of the hydrorefining product stream is 325°C; the temperature rise after passing through the protective agent is 30°C, and the temperature rises of the contact reactions are 55°C, 20°C, and 5°C, respectively.

[0230] The catalyst evaluation results are shown in Table 1 (hydrorefining) and Table 2 (hydrocracking).

[0231] Table 1

[0232] project Naphthalene conversion rate % Tetrahydronaphthalene selectivity % Nitrogen ppm sulfur ppm Example 1 98.5 99.5 0.6 0.6 Example 2 99.1 98.8 0.2 0.5 Example 3 98.6 98.8 0.7 0.8 Example 4 98.1 98.0 0.5 0.8 Example 5 92.8 94 0.9 1.8 Example 6 93 94 1.1 0.9 Example 7 92 88 1.9 4.6 Example 8 95.4 88 1.2 3.5 Example 9 95.1 89.8 0.2 1.5 Example 10 89 90 5.9 12 Example 11 95.4 92 1.2 2.0 Example 12 89 93 3.4 5.6 Example 13 98.5 99.5 0.6 0.6 Example 14 98.5 99.5 0.6 0.6 Example 15 89.1 90.5 6.1 11 Example 16 92.1 93 2.8 5.9 Comparative Example 1 90.5 82 6 14 Comparative Example 2 86 80 23 39

[0233] Table 2

[0234]

[0235]

[0236] Table 3

[0237]

[0238] The preferred 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 combinations of 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 hydrogenating ethylene tar, characterized in that, The method includes: in the presence of a hydrorefining catalyst, ethylene tar feedstock and hydrogen undergo at least two consecutive contact reactions with successively increasing temperatures to obtain a hydrorefined product; The temperature rise for each contact reaction is 0.5-50℃ / time.

2. The method according to claim 1, wherein, The ethylene tar feedstock undergoes 3-5 consecutive temperature-increased contact reactions with hydrogen; and / or The temperature rise for each contact reaction is 2-35℃ / cycle.

3. The method according to claim 1 or 2, wherein, The temperature of the hydrorefined product is 30-90°C higher than the temperature of the ethylene tar feedstock, preferably 30-80°C, more preferably 35-80°C; even more preferably, The temperature of the hydrogenation refining product is 295-370℃, preferably 295-325℃; and / or The temperature of the ethylene tar feedstock is 200-300℃, preferably 215-250℃.

4. The method according to any one of claims 1-3, wherein, Along the material flow direction, at least two types of hydrorefining catalysts are sequentially loaded, and the pore size gradient of the catalysts decreases. Preferably, The pore size of adjacent catalyst packs decreases by 2-25 nm; and / or The packing volume ratio of adjacent catalyst packs is (1-3):(1-3).

5. The method according to any one of claims 1-4, wherein, In the ethylene tar feedstock: The naphthalene content is ≤55wt%; and / or the final boiling point is ≤350℃; and / or the bromine value is ≤50gBr / 100g oil; and / or the gum content is ≤100mg / 100ml oil; and / or the sulfur content is ≤600ppm; and / or the nitrogen content is ≤70ppm.

6. The method according to any one of claims 1-5, wherein, Each of the aforementioned hydrorefining catalysts is a hydrogenation active component supported catalyst, which comprises a support and a hydrogenation active component supported on the support in the form of a sulfide. Preferably, the sulfide is distributed in a tower-like shape on the catalyst surface; More preferably, The number of stacking layers of the tower type is 3-10, preferably 3-5; and / or the stacking length of the tower type is 3-12 nm, preferably 3-6 nm; and / or the stacking layer spacing of the tower type is 0.2-2 nm; and / or Based on the total mass of the hydrogenated active component supported catalyst before sulfidation, the total content of the hydrogenated active component in the supported catalyst, calculated as oxides, is not less than 30 g / L, preferably 50-700 g / L, and more preferably 60-650 g / L; and / or The average pore size of the carrier is 7-20 nm; and / or the pore volume of the carrier is 0.5-0.98 cm³. 3 / g; and / or the specific surface area of ​​the carrier is 190-380m². 2 / g.

7. The method according to any one of claims 1-6, wherein, Before the contact reaction, the ethylene tar feedstock and hydrogen are first contacted with a protective agent for a pre-reaction. The protective agent includes hydrogenated active metal oxides and oxide carriers, and the content of hydrogenated active metal oxides in the protective agent is 5-60 g / L carrier. Preferably, The ratio of the loading volume of the protective agent to the total loading volume of the hydrorefining catalyst is 1:4-25, preferably 1:4-10; and / or The temperature of the pre-reaction is not higher than the temperature of the first contact reaction, and the reaction conditions include: a temperature of 200-290℃; and / or a pressure of 2.0-8.0 MPa; and / or a hydrogen-to-oil volume ratio of 400-3000; and / or a liquid hourly space velocity of 0.2-3 h⁻¹. -1 .

8. The method according to claim 7, wherein, The protective agent has an average pore size of 20-30 nm; and / or The pore volume of the protective agent is 0.5-0.98 cm³. 3 / g; and / or The specific surface area of ​​the protective agent is 200-240 m². 2 / g; Preferably, The hydrogenated active metal in the protective agent is selected from at least one of Ni, Mo, W and Co, and / or The oxide carrier in the protective agent is Al2O3.

9. The method according to any one of claims 1-8, wherein, The conditions for the contact reaction include: a temperature of 200-300℃, preferably 250-300℃; and / or a pressure of 2.0-8.0 MPa, preferably 2.2-6.0 MPa; and / or a hydrogen-to-oil volume ratio of 400-3000, preferably 600-2000; and / or a liquid hourly space velocity of 0.2-3 h⁻¹. -1 Preferably 0.6-1.2h -1 .

10. The method according to any one of claims 1-9, wherein, The method further includes: sequentially purifying and hydrocracking the hydrorefined product; preferably, After purification, the hydrogenated product has the following characteristics: sulfur content ≤ 1 ppm, preferably ≤ 0.85 ppm; and / or nitrogen content ≤ 1 ppm, preferably ≤ 0.8 ppm; and / or The purified stream of the hydrogenated product is 0-99 wt%, preferably 10-50 wt%, recycled back to the contact reaction process; and / or At least a portion of the heavy aromatics in the hydrocracking products of the hydrocracking process are recycled back to the ethylene tar feedstock. More preferably, The conditions for the hydrocracking treatment include: a temperature of 260-500℃, preferably 260-480℃; and / or a pressure of 2.0-8.0 MPa, preferably 3.0-6.5 MPa; and / or a hydrogen-to-oil volume ratio of 400-3000, preferably 600-2000; and / or a liquid hourly space velocity of 0.2-3 h⁻¹. -1 Preferably 0.6-1.2h -1 .

11. The method according to claim 10, wherein, The hydrocracking process uses a hydrocracking catalyst, and the TPR hydrogen atmosphere reduction temperature of the hydrocracking catalyst is below 400℃, preferably 350-390℃. and / or The hydrocracking catalyst comprises a Group VIII metal element, optionally a lanthanide metal element, optionally a Group IVB metal element, and a molecular sieve support; preferably, The Brønsted acid / Lylene acid ratio of the molecular sieve support is 0.5-12, preferably 1.5-7.3; and / or The molecular sieve support has a particle size ≤1000nm, preferably 100-500nm; and / or The molecular sieve support has a pore size of 5-10 nm; and / or The molecular sieve support has a pore volume of 0.2-0.3 cm³. 3 / g; and / or The specific surface area of ​​the molecular sieve carrier is ≥250m². 2 ·g -1 Preferably 250-400m 2 ·g -1 ; and / or The SiO2 / Al2O3 molar ratio of the molecular sieve support is 10-200, preferably 15-60; and / or The dispersion of Group VIII metal elements in the hydrocracking catalyst is greater than 8%, preferably 8-15%; and / or The Group VIII metallic element is selected from at least one of Ni, Pt, and Pd, preferably Ni and / or Pt; and / or The lanthanide metal element is selected from Ce and / or La, preferably Ce; and / or The group IVB metal element is selected from Zr and / or Ti, preferably Zr.

12. The method according to claim 11, wherein, The hydrocracking catalyst contains Group VIII metal elements in an oxide concentration of 50-260 g / L of the support, preferably 50-150 g / L; and / or The lanthanide metal element content in the hydrocracking catalyst, calculated as oxide, is 0.1-100 g / L of the support, preferably 0.1-50 g / L; and / or The oxide content of Group IVB metal elements in the hydrocracking catalyst is 0.1-100 g / L of the support, preferably 0.1-50 g / L of the support; The molecular sieve carrier includes at least one of nano HZSM-5 molecular sieve, nano HMor molecular sieve, nano HZSM-11 molecular sieve, nano HUSY molecular sieve, nano Hβ molecular sieve, nano HMCM-22 molecular sieve and nano HMCM-41 molecular sieve, preferably nano HZSM-11 molecular sieve.

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