Catalyst for preparing high-density special fuel from high-temperature coal tar as well as grading method and application of catalyst

Abstract

The invention discloses a catalyst for preparing high-density special fuel from high-temperature coal tar as well as a grading method and application of the catalyst, and belongs to the technical field of preparation of high-density special fuel. The catalyst is composed of a hydrogenation protective agent, a hydrofining agent, a hydrocracking agent and a hydroisomerization agent; sulfur, nitrogen, oxygen, metal impurities, olefin and the like in the high-temperature coal tar are removed through catalyst grading of all bed layers in the reactor, aromatic hydrocarbon saturation, cracking and isomerization are carried out under proper process conditions, finally, the coal tar is purified, the oil quality is improved, and high-density special fuel is prepared. The catalyst has high catalytic efficiency for preparing high-density special fuel through hydrogenation of high-temperature coal tar, the yield of the high-density special fuel is high, the density can reach 901kg / m < 3 >, the low-temperature condensation point is-56 DEG C, and the calorific value is 42.6 MJ / kg. The grading mode of the catalyst has excellent hydrogenation activity and stability, the cracking degree is reduced, the saturated isomerization reaction is increased, and the high-density special fuel with higher yield can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of high-density special fuel preparation technology, specifically relating to a catalyst for preparing high-density special fuel from high-temperature coal tar, its grading method, and its application. Background Technology

[0002] Coal tar is a major byproduct of coal pyrolysis. High-temperature coal tar is primarily composed of aromatic and heterocyclic compounds, mostly polycyclic and fused-ring compounds with or without side chains, and heterocyclic compounds containing oxygen, sulfur, and nitrogen. Its pitch content is typically above 50%, making it generally viscous with a relative density greater than water and exhibiting a black or dark brown color. Furthermore, high-temperature coal tar contains significant amounts of sulfur, nitrogen, oxygen, and mechanical impurities, making it prone to condensation reactions. This makes its hydrogenation process relatively difficult. The hydrogenation products of high-temperature coal tar are polycyclic alkanes, whose unique composition gives them high density and volumetric calorific value, making them ideal for processing into high-density fuels. However, due to their significant compositional variations, they should be modified before being used to produce high-density fuels.

[0003] High-density specialty fuels typically refer to jet fuels used for special purposes, such as military aircraft, high-altitude probes, and rockets. They are characterized by high energy density, low combustion temperature, high thermal efficiency, and good combustion controllability. The main components of high-density specialty fuels are hydrocarbons, such as cycloalkanes and their isomers, along with additives such as antiknock agents and heat stabilizers. The chemical composition of high-density specialty fuels has a significant impact on carbon deposit formation. In engines, aromatic hydrocarbons, especially bicyclic aromatic hydrocarbons, readily form carbon deposits. Therefore, the content of bicyclic aromatic hydrocarbons and other aromatic substances in high-density specialty fuels must be strictly limited. Coal tar hydrogenation can remove, crack, or isomerize some aromatic compounds to produce clean gasoline and diesel, although the aromatic content is still relatively high. By improving and optimizing the hydrogenation process and technology, the oil can be hydrogenated and isomerized to obtain high-density coal-based specialty oils. The catalyst is the core of the entire hydrogenation reaction. By improving the hydrogenation catalyst system, the quality of the oil can be significantly improved. Therefore, this invention aims to produce high-density, high-flash-point, low-crystallization-point, and component-concentrated high-performance jet fuel through coal tar hydrogenation.

[0004] Since the 1950s, the main jet fuels used in the United States have been the RJ-4, RJ-5, RJ-7, JP-5, JP-9, and JP-10 series. These fuels are all synthetic hydrocarbon fuels with high production costs. The Pennsylvania Energy Research Institute (Fuel Processing Technology 89 (2008) 364-378) mixed catalytic cracked diesel (LCO) and coal-based liquefied petroleum oil at a 1:1 volume ratio and then hydrogenated them to obtain the primary coal-based jet fuel, JP-900. The density (20 °C) of RP-3 jet fuel, the most widely used dual-use military and civilian jet fuel in my country, ranges from 0.775 to 0.830 g / cm³. 3 Its volumetric calorific value is approximately 35.5 MJ / L, while the density (at 20 °C) of high-energy jet fuels is greater than 0.900 g / cm³. 3 Its volumetric calorific value is higher than 38.3 MJ / L. Therefore, researching the use of high-temperature coal tar as raw material to convert aromatics into cycloalkanes through hydrogenation to produce high-density jet fuel is an effective way to utilize high-temperature coal tar for high value and is also the preferred route for developing coal-based special fuels in my country.

[0005] Chinese patent CN105694970A discloses a method for producing high-density jet fuel by hydrogenating low-temperature coal tar. The method involves hydrogenating medium-low temperature coal tar using a hydrogenation protective catalyst and a hydrogenation refining catalyst, followed by clay refining of the crude jet fuel to obtain high-density No. 6 jet fuel with a density of 910 kg / m³. 3 The aromatic hydrocarbon content is 7%, the low-temperature freezing point is -48℃, and the yield is about 60%. However, the patented multi-stage hydrogenation (protection + purification) combined process with fractionation and clay purification has a long process, large equipment investment, and the clay needs to be replaced regularly, generating solid waste and secondary treatment costs.

[0006] Chinese patent CN 118725889A discloses a method for preparing high-density coal-based jet fuel by modifying coal tar with NA anhydride. This method utilizes a modifier to perform ring-enhancing modification on coal tar distillate, increasing the content of tricyclic or higher-ring components in the coal tar distillate by approximately 20%. The modifier used is NA anhydride, and the catalyst is a Lewis acid. The solvent / extractant needs to be recovered, making the process complex. The content of tricyclic or higher-ring compounds increases from 14.91% to 33.18%. This patent does not perform aromatic saturation; the carbon deposits from aromatic combustion cannot be directly used as jet fuel and require subsequent hydrogenation treatment. Chinese patent CN 118813292A discloses a method for synthesizing high-density fuel based on phenolic molecules in coal tar. It utilizes dibenzyl ether as a modifier to achieve ring-enhancing modification of the coal tar, thereby increasing the density and calorific value of the high-density fuel. In a fixed-bed reactor, Pd / C is added, resulting in a catalyst density >1.08 g / ml, a net calorific value of 42-43 MJ / L, and a freezing point ≤-70℃. However, in this patent, the phenols are not hydrotreated for deoxygenation, and the combustion of oxygenated compounds produces water. Therefore, this fuel cannot be directly used as a special jet fuel and requires hydrotreating to obtain the final product.

[0007] Coal tar hydrogenation technology removes sulfur, nitrogen, metals, and other heteroatoms from coal tar under specific temperature, pressure, and catalyst conditions, and saturates it with aromatic compounds, thereby producing a blending component for clean fuel oil. Low-temperature and medium-temperature coal tar differ significantly in properties from high-temperature coal tar. Current technologies for hydrogenating heavy components of high-temperature coal tar exhibit poor catalyst conversion efficiency, resulting in products with substandard density and aromatic content.

[0008] Based on the problems existing in the prior art, this invention focuses on directional regulation of ring structure, improvement of heavy component conversion, and optimization of the performance of graded hydrogenation catalysts to achieve efficient conversion of coal tar into high-density clean fuel oil and enhance product market competitiveness. Summary of the Invention

[0009] This invention aims to provide a catalyst, its assembly method, and its application. Using high-temperature coal tar as raw material, it develops a utilization technology for producing high-density special fuels from high-temperature coal tar. This provides a new clean and efficient utilization technology route for special fuels in my country, expands the applications of coal-based fuels, and is of great significance to the development of coal-based fuel technology in my country.

[0010] This invention uses high-temperature coal tar as raw material. High-temperature coal tar has superior aromatic compounds compared to medium- and low-temperature coal tar, and its hydrogenation products, including cycloalkanes, are significantly more abundant, making it more suitable for jet fuel. It also boasts high density, high yield, and low pour point. The hydrogenation catalyst used in this invention has NiO, MoO3, and WO3 as active metal components, with the remainder being a support. The support consists of γ-Al2O3, Y, and SAPO-11 molecular sieves, all of which are commercially available. The catalyst is prepared via a saturated impregnation method. This invention utilizes high-temperature coal tar hydrogenation to produce high-density specialty fuels in a fixed-bed reactor. The designed catalyst gradation method results in high hydrogenation efficiency, eliminates solvent recovery steps, and allows for industrial application of the catalyst. The entire preparation process is simple to operate. The catalyst gradation method described in this invention possesses high demetallization capability, high water resistance, excellent hydrotreating saturated isomerization activity, and stability. It can meet the catalyst performance requirements for long-term stable operation of hydrotreating units. Simultaneously, it improves the type of oil hydrotreating, reduces the degree of cracking, and increases saturated isomerization reactions. Therefore, under suitable process conditions, it can produce high-density specialty fuels with a higher yield. These high-density specialty fuels have a density ≥0.9 g / ml, a calorific value ≥42.5 MJ / L, and a pour point ≤-56℃. Existing tar hydrotreating enterprises can produce high-density specialty fuels after improvements, significantly enhancing their economic and social benefits.

[0011] This invention provides a catalyst for preparing high-density special fuels from high-temperature coal tar, which is composed of a hydroprotecting agent, a hydrorefining agent, a hydrocracking agent, and a hydroisomerizing agent; The hydrogenation protective agent is a bird's nest-shaped hydrogenation protective agent and a Mo-Ni four-blade hydrogenation protective agent; The hydrogenation refining agent is a self-made W-Mo-Ni / γ-Al2O3 hydrogenation refining catalyst. Preparation method: Ammonium metatungstate (a tungsten trioxide precursor), ammonium heptamolybdate (a molybdenum trioxide precursor), and nickel nitrate Ni(NO3)2·6H2O (a nickel monoxide precursor) are added to an ammonia solution at a concentration of 25-30% (mass concentration). The solution is stirred at 60°C until completely dissolved to obtain an active component solution. This active component solution is then impregnated into the γ-Al2O3 support (saturated impregnation method) for 3-5 hours. The solution is then dried at 20-30°C for 5-8 hours, followed by drying at 100°C for 6-8 hours. Finally, the temperature is increased to 450-550°C at a rate of 2-6°C / min, and calcined for 6-8 hours to obtain the hydrogenation refining agent.

[0012] The hydrocracking agent is a self-made W-Ni / γ-Al2O3 / Y hydrocracking catalyst. Preparation method: Ammonium metatungstate (a tungsten trioxide precursor) and nickel nitrate (Ni(NO3)2·6H2O) (a nickel monoxide precursor) are added to distilled water according to their concentration ratios. The mixture is stirred at 15-60℃ until completely dissolved to obtain an active component solution. This active component solution is then impregnated into the γ-Al2O3 / Y support (γ-Al2O3 to Y support mass ratio is 8:2) using the saturated impregnation method for 3-5 hours. The mixture is then dried at 20-30℃ for 5-8 hours, and then dried at 100℃ for 6-8 hours. Finally, the temperature is increased to 450-550℃ at a rate of 2℃ / min-6℃ / min, and calcined for 6-8 hours to obtain the hydrocracking agent.

[0013] The hydroisomerizing agent is a self-made W-Ni / γ-Al2O3 / SAPO-11 hydroisomerizing catalyst. Preparation method: Ammonium metatungstate (a tungsten trioxide precursor) and nickel nitrate (Ni(NO3)2·6H2O) (a nickel monoxide precursor) are added to distilled water according to their concentration ratios. The mixture is stirred at 15-60℃ until completely dissolved to obtain an active component solution. This active component solution is then impregnated into the support γ-Al2O3 / SAPO-11 (γ-Al2O3 to SAPO-11 mass ratio of 8:2) using the saturated impregnation method for 3-5 hours. The mixture is then dried at 20-30℃ for 5-8 hours, and then dried at 100℃ for 6-8 hours. Finally, the temperature is increased to 450-550℃ at a rate of 2℃ / min-6℃ / min, and calcined for 6-8 hours to obtain the hydroisomerizing agent.

[0014] Furthermore, the bird's nest-shaped hydrogenation protective agent has a size of Φ(6~45)mm×(6~15)mm, a porosity of 60%~70%, and a specific surface area of ​​800m². 2 / g~2000m 2 / g.

[0015] Furthermore, the Mo-Ni hydrogenation protectant is a Mo-Ni / γ-Al2O3 protectant, in which the active component comprises 0.7–3.1% MoO3 oxide and 1.3–4% NiO; the Mo-Ni hydrogenation protectant is four-bladed, with dimensions of Φ(1.7–8.0) mm × (3–10) mm, and a bulk density of 0.43 g / cm³. 3 ~0.80g / cm 3 ; Specific surface area is 100m² 2 / g~150m 2 / g; pore volume 0.3cm 3 / g~0.7cm 3 / g.

[0016] Furthermore, the active component in the W-Mo-Ni hydrorefining agent comprises 20-40% by oxide content; the hydrorefining agent is prepared by an equal-volume impregnation method using Ni, Mo, and W as active components and γ-Al2O3 as a support, with NiO loading of 2-5%, MoO3 loading of 7-27%, WO3 loading of 5-12%, and the remainder as γ-Al2O3 support. The Mo-Ni hydrorefining catalyst is clover-shaped, with a size of Φ(1.8-3.5)mm×(3-8)mm and a bulk density of 0.65g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~300m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g.

[0017] Furthermore, the active component in the W-Ni hydrocracking catalyst comprises 20-30% by weight of oxides, with Ni and W as the active components and γ-Al₂O₃ + molecular sieve Y as the support. It is prepared by an equal-volume impregnation method, with NiO loading of 5-7%, WO₃ loading of 15-23%, and the remainder as γ-Al₂O₃ + molecular sieve Y support. The W-Ni hydrocracking catalyst is in strip shape, with dimensions of Φ(2.0-3.5) mm × (3-8) mm and a bulk density of 0.65 g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~350m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g.

[0018] Furthermore, the active component in the W-Ni hydroisomerizer comprises 18–22% by weight of oxides, with Ni and W as the active components and γ-Al₂O₃+ molecular sieve SAPO-11 as the support. It is prepared by an equal-volume impregnation method, with NiO loading of 3–6%, WO₃ loading of 13–18%, and the remainder supported by γ-Al₂O₃+ molecular sieve SAPO-11. The W-Ni hydroisomerizer catalyst is in strip shape, with dimensions of Φ(2.0–3.5) mm × (3–8) mm and a bulk density of 0.65 g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~350m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g.

[0019] This invention provides a method for grading the catalyst used to prepare high-density special fuels from high-temperature coal tar, wherein the following catalysts are sequentially loaded along the material flow direction in the reactor: (1) a bird's nest-shaped hydrogenation protectant, with a loading ratio of 4-10%; (2) a Mo-Ni / γ-Al2O3 protectant, with a loading ratio of 10-16%; (3) a W-Mo-Ni / γ-Al2O3 hydrogenation refining catalyst, with a loading ratio of 25-50%; (4) a W-Ni / γ-Al2O3 / Y hydrocracking catalyst, with a loading ratio of 15-30%; and (5) a W-Ni / γ-Al2O3 / SAPO-11 hydroisomerization catalyst, with a loading ratio of 10-30%. Inert ceramic balls are filled at the top and bottom of the catalyst, with a loading ratio of 5%-10% of the reactor volume. The inert ceramic balls have high mechanical strength and can provide stable support for the catalyst. The above loading ratios are volume percentages.

[0020] This invention provides the application of the above-mentioned catalyst in the preparation of high-density special fuels from high-temperature coal tar.

[0021] In the above applications, a fixed-bed reactor is used. Through the gradation of catalysts in each bed inside the reactor, sulfur, nitrogen, oxygen, metal impurities and olefins are removed from high-temperature coal tar. Under appropriate process conditions, aromatic saturation, cracking and isomerization are carried out, and finally the coal tar is purified to improve the quality of the oil and produce high-density special fuels.

[0022] The specific method is as follows: First, in a fixed-bed reactor, the catalyst is loaded sequentially from top to bottom with bird's nest-shaped hydrogenation protectant, Mo-Ni hydrogenation protectant, W-Mo-Ni hydrogenation refining agent, W-Ni hydrogenation cracking agent, and W-Ni hydrogenation isomerizing agent. Inert ceramic balls are filled at the top and bottom of the catalyst, respectively. The catalyst is placed in the middle isothermal zone of the reactor. The pipeline is sealed and leak checked. Then, the catalyst is sulfided using CS2 kerosene solution as the sulfiding liquid. The temperature is raised to 300℃~370℃ under a hydrogen pressure of 2.0MPa~4.0 MPa, and the volume hourly space velocity is set to 0.2h. -1 ~0.5 h -1 Under conditions of a hydrogen-to-oil ratio of 600-1200, continuous sulfidation is carried out for 24-48 hours. After sulfidation, once the temperature has dropped to room temperature, the feed line is switched to raise the temperature to 320-380℃, and coal tar feedstock is pumped in at 4-8 MPa, with a hydrogen-to-oil volume ratio of 800-1500 and a liquid hourly space velocity of 0.1 h⁻¹. -1 ~0.3 h -1 Under certain conditions, a hydrogenation reaction is carried out. After 24 hours of reaction, the oil product is obtained. The 190℃~300℃ fraction is then cut to obtain the high-density special fuel.

[0023] Furthermore, high-temperature coal tar refers to the <360℃ high-temperature coal tar fraction, which is the high-temperature coal tar fraction oil after the bituminous components have been removed.

[0024] This invention relates to the hydrogenation of high-temperature coal tar to produce high-density specialty fuels, exhibiting high catalytic efficiency, high yield of high-density specialty fuels, and a density reaching 901 kg / m³. 3 With a low-temperature pour point of -56℃ and a calorific value of 42.6 MJ / kg, all other indicators comply with GB 6537-2018. The catalyst gradation method has excellent hydrogenation activity and stability, reduces the degree of cracking, and increases saturated isomerization reaction. Therefore, under suitable process conditions, a higher yield of high-density special fuel can be obtained.

[0025] The beneficial effects of this invention are: The catalyst selected in this invention is a highly efficient catalyst for the preparation of high-density special fuels from coal tar. It has good performance, stable activity, reduces operating costs, and is suitable for continuous large-scale industrial production. It is a special catalyst for the preparation of high-density special fuels from coal tar, with a maximum coal tar conversion rate of up to 97%. The catalyst can be recovered and reactivated for reuse. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the assembly of the catalyst of the present invention in a fixed-bed reactor. Detailed Implementation

[0027] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments.

[0028] Table 1 Characteristics of High-Temperature Coal Tar

[0029] Table 1 lists the characteristic indicators of high-temperature coal tar. The data shows that high-temperature coal tar has a high density, high pitch content (approximately 55%), and is rich in valuable chemicals such as naphthalene, phenanthrene, anthracene, fluoranthene, acenaphthene, pyrene, carbazole, and cresol. Pitch can be used as a raw material for carbon-based materials, therefore it requires processing. Traditional coal tar is processed through distillation and other methods to obtain chemicals. For high-temperature coal tar to become a special clean fuel, it must undergo hydrogenation treatment to remove sulfur, nitrogen, oxygen, metallic impurities, and saturated cracking of olefins and aromatics. Example 1

[0030] The bird's nest-shaped hydrogenation protectant involved in the embodiments of this invention was purchased from Jiangxi Yingtao Kangshun Industrial Co., Ltd., and has a specific surface area of ​​800~2000 μm. 2 / g, with dimensions of Φ(6~45)mm×(6~15)mm and a porosity of 60%~70%; the Mo-Ni hydrogenation protectant was purchased from Zibo Luyuan Industrial Catalyst Co., Ltd., and the active components, calculated as oxides MoO3 and NiO, have a content of 3~16%; the Mo-Ni hydrogenation protectant is a four-bladed wheel, with dimensions of Φ(1.7~8.0)mm×(3~10)mm and a bulk ratio of 0.43g / cm³. 3 ~0.80g / cm 3 ; Specific surface area is 100m² 2 / g~150m 2 / g; pore volume 0.3cm 3 / g~0.7cm 3 / g.

[0031] The hydrogenated refining agent, hydrogenated cracking agent, and hydrogenated isomerizing agent are prepared in-house.

[0032] Preparation method of hydrogenation refining agent: Ammonium metatungstate (tungsten trioxide precursor), ammonium heptamolybdate (molybdenum trioxide precursor), and nickel nitrate Ni(NO3)2·6H2O (nickel monoxide precursor) are added to an ammonia solution (ammonium concentration 25-30%) according to their concentration ratio. The solution is stirred at 60℃ until completely dissolved to obtain an active component solution. This active component solution is then used to impregnate a γ-Al2O3 support for 5 hours, followed by drying at 20℃ for 5 hours and then at 100℃ for 6 hours. The temperature is then increased to 550℃ at a rate of 6℃ / min and calcined for 6 hours to obtain the catalyst. The percentages of each component are shown in Table 2.

[0033] Preparation method of hydrocracking catalyst: Ammonium metatungstate, a tungsten trioxide precursor, and nickel nitrate (Ni(NO3)2·6H2O), a nickel monoxide precursor, are added to distilled water according to their concentration ratios. The mixture is stirred at 60°C until completely dissolved to obtain an active component solution. This active component solution is then used to impregnate a γ-Al2O3 / Y support (γ-Al2O3 / Y mass ratio 8:2) for 5 hours. After impregnation, the solution is dried at 20°C for 5 hours and then at 100°C for 6 hours. Finally, the temperature is increased to 550°C at a rate of 6°C / min, and calcined for 6 hours to obtain the catalyst. The percentages of each component are shown in Table 2.

[0034] Preparation method of hydroisomerizer: Ammonium metatungstate, a tungsten trioxide precursor, and nickel nitrate (Ni(NO3)2·6H2O), a nickel monoxide precursor, were added to distilled water according to their concentration ratios. The mixture was stirred at 60°C until completely dissolved to obtain an active component solution. The support γ-Al2O3 / SAPO-11 (γ-Al2O3 / SAPO-11 mass ratio 8:2) was then impregnated with the active component solution for 5 h, dried at 20°C for 5 h, and then dried at 100°C for 6 h. Finally, the temperature was increased to 550°C at a rate of 6°C / min, and calcined for 6 h to obtain the catalyst. The percentages of each component are shown in Table 2.

[0035] Table 2 Catalyst parameters for examples

[0036] The application of high-temperature coal tar hydrogenation to produce special fuels involves the following steps: In a fixed-bed reactor, the catalyst is loaded sequentially from top to bottom with inert ceramic balls, a bird's nest-shaped hydrogenation protectant, another hydrogenation protectant, a hydrogenation refining agent, a hydrocracking agent, a hydroisomerizing agent, and then inert ceramic balls again. The loading ratio is bird's nest-shaped hydrogenation protectant: Mo-Ni hydrogenation protectant: hydrogenation refining agent: hydrocracking agent: hydroisomerizing agent = 10:10:50:20:10. Inert ceramic balls are filled at both the top and bottom of the catalyst (8% of the reactor volume). The process conditions and product properties are shown in Table 2. The catalyst is placed in the central isothermal zone of the reactor. The pipeline is sealed and leak-checked. The catalyst is then sulfided using CS2 kerosene solution as the sulfiding liquid. The temperature is raised to 300℃ under a hydrogen pressure of 2.0 MPa, and the volume hourly space velocity is set to 0.2 h⁻¹. -1 Under a hydrogen-to-oil ratio of 1200, continuous sulfidation was carried out for 48 hours. After sulfidation, the temperature was allowed to drop to room temperature before switching to the feed line to raise the temperature to 320°C. Coal tar feedstock was then pumped in at 4 MPa, with a hydrogen-to-oil volume ratio of 800 and a liquid hourly space velocity of 0.1 h⁻¹. -1 Hydrogenation was carried out under specific conditions. After 24 hours of reaction, the oil product was obtained. The fraction distilled at 190-300℃ was then separated to obtain the high-density special fuel. The product yield and other performance indicators are shown in Table 2. Example 2

[0037] The bird's nest-shaped hydrogenation protectant and the Mo-Ni hydrogenation protectant used in this embodiment are the same as those in Example 1.

[0038] The hydrorefining agent, hydrocracking agent, and hydroisomerizing agent have different compositions, but the preparation process conditions are basically the same. The preparation process is as follows: the materials are prepared according to the data in Table 2, and the preparation process conditions are: impregnation for 3 hours, drying at 30℃ for 6 hours, drying at 100℃ for 7 hours, and then heating to 450℃ at a heating rate of 2℃ / min and calcining for 7 hours to obtain the catalyst.

[0039] In a fixed-bed reactor, bird's nest-shaped hydroprotectant, Mo-Ni hydroprotectant, hydrorefining agent, hydrocracking agent, and hydroisomerizer were loaded from top to bottom in a ratio of bird's nest-shaped hydroprotectant: Mo-Ni hydroprotectant: hydrorefining agent: hydrocracking agent: hydroisomerizer = 4:16:35:15:30. The process conditions and product properties are shown in Table 3. Other process conditions in this embodiment are the same as in Example 1. Example 3

[0040] The bird's nest-shaped hydrogenation protectant and the Mo-Ni hydrogenation protectant used in this embodiment are the same as those in Example 1.

[0041] Although the compositions of the hydrorefining agent, hydrocracking agent, and hydroisomerizing agent are different, the preparation process conditions are basically the same. The preparation process is as follows: the materials are prepared according to the data in Table 2, and the preparation process conditions are: impregnation for 4 hours, drying at 25℃ for 7 hours, drying at 100℃ for 8 hours, and then heating to 500℃ at a heating rate of 4℃ / min and calcining for 8 hours to obtain the catalyst.

[0042] In a fixed-bed reactor, bird's nest-shaped hydroprotectant, Mo-Ni hydroprotectant, hydrorefining agent, hydrocracking agent, and hydroisomerizer were loaded from top to bottom in a ratio of 8:12:30:30:20. The process conditions and product properties are shown in Table 3. Other process conditions in this embodiment are the same as in Example 1. Example 4

[0043] The bird's nest-shaped hydrogenation protectant and the Mo-Ni hydrogenation protectant used in this embodiment are the same as those in Example 1.

[0044] Although the compositions of the hydrorefining agent, hydrocracking agent, and hydroisomerizing agent are different, the preparation process conditions are basically the same. The preparation process is as follows: the materials are prepared according to the data in Table 2, and the preparation process conditions are: impregnation for 5 hours, drying at 20℃ for 8 hours, drying at 100℃ for 6 hours, and then heating to 550℃ at a heating rate of 5℃ / min and calcining for 6 hours to obtain the catalyst.

[0045] In a fixed-bed reactor, bird's nest-shaped hydroprotectant, Mo-Ni hydroprotectant, hydrorefining agent, hydrocracking agent, and hydroisomerizer were loaded from top to bottom in a ratio of 6:14:25:25:30. The process conditions and product properties are shown in Table 3. Other process conditions in this embodiment are the same as in Example 1.

[0046] Table 3 Process parameters and special fuel indicators of the embodiments .

[0047] Comparative Example 1 Compared to Example 1, the high-temperature coal tar was replaced with medium- and low-temperature coal tar, while other quantities remained unchanged. The resulting high-density fuel performance was tested and found to have a density of 830 kg / m³. 3 It has a net calorific value of 39.4 MJ / kg, a freezing point of -48℃, and an aromatic hydrocarbon content of 10.50%.

[0048] Comparative Example 2 Compared to Example 1, the hydroisomerization catalyst was replaced with the same amount of hydrorefining agent, while other quantities remained unchanged. The resulting high-density fuel performance test showed a density greater than 950 kg / m³. 3 It has a net calorific value of 39.6 MJ / kg, a freezing point of -57℃, and an aromatic hydrocarbon content of 22.05%.

[0049] Comparative Example 3 Compared to Example 1, the hydrocracking catalyst was replaced with the same amount of hydrorefining agent, while other quantities remained unchanged. The resulting high-density fuel performance test showed a density greater than 880 kg / m³. 3 It has a net calorific value of 39.1 MJ / kg, a freezing point of -49℃, and an aromatic hydrocarbon content of 8.55%.

[0050] Comparative Example 4 Compared to Example 1, the hydrorefining catalyst was replaced with the same amount of hydrocracking agent, while other quantities remained unchanged. The resulting high-density fuel performance test showed a density greater than 820 kg / m³. 3 It has a net calorific value of 39.5 MJ / kg, a freezing point of -44℃, and an aromatic hydrocarbon content of 8.59%.

[0051] Based on the above test results, it can be seen that the high-density fuel of this application has good quality (considering all performance indicators). Comparative Example 1 has a low density, Comparative Example 2 has a high density but a high aromatic content, which causes carbon deposits and is not conducive to combustion. Comparative Examples 3 and 4 have low density and calorific value.

[0052] The above description is merely a preferred embodiment of the present invention, and various modifications and variations are possible. Any modifications, equivalent substitutions, improvements, etc., made in accordance with the claims of this invention shall fall within the scope of this invention.

Claims

1. A catalyst for preparing high-density special fuels from high-temperature coal tar, characterized in that, It consists of a hydrogenation protectant, a hydrogenation refining agent, a hydrogenation cracking agent, and a hydrogenation isomerizing agent; The hydrogenation protective agent is a bird's nest-shaped hydrogenation protective agent and a Mo-Ni four-blade hydrogenation protective agent; The hydrogenation refining agent is a W-Mo-Ni / γ-Al2O3 hydrogenation refining catalyst; the active component in the W-Mo-Ni hydrogenation refining agent has a content of 20-40% based on oxides; the hydrogenation refining agent is prepared by an equal-volume impregnation method with Ni, Mo, and W as active components and γ-Al2O3 as support, and the NiO loading is 2-5%, the MoO3 loading is 7-27%, the WO3 loading is 5-12%, and the remainder is γ-Al2O3 support; The hydrocracking agent is a W-Ni / γ-Al2O3 / Y hydrocracking catalyst; the active component in the W-Ni hydrocracking agent is 20-30% based on oxides, with Ni and W as active components and γ-Al2O3+ molecular sieve Y as support, and is prepared by equal volume impregnation method, with NiO loading of 5-7%, WO3 loading of 15-23%, and the remainder being γ-Al2O3+ molecular sieve Y support; The hydroisomer is a W-Ni / γ-Al2O3 / SAPO-11 hydroisomerization catalyst; the active component in the W-Ni hydroisomer has a content of 18-22% based on oxides, with Ni and W as active components and γ-Al2O3+ molecular sieve SAPO-11 as support, and is prepared by equal volume impregnation method, with NiO loading of 3-6%, WO3 loading of 13-18%, and the remainder being γ-Al2O3+ molecular sieve SAPO-11 support.

2. The catalyst for preparing high-density special fuels from high-temperature coal tar according to claim 1, characterized in that, The preparation method of the hydrogenated refining agent is as follows: Ammonium metatungstate (a tungsten trioxide precursor), ammonium heptamolybdate (a molybdenum trioxide precursor), and nickel nitrate Ni(NO3)2·6H2O (a nickel monoxide precursor) are added to an ammonia solution at a concentration of 25-30% according to the specified ratio. The solution is stirred at 15-60°C until completely dissolved to obtain an active component solution. The active component solution is then used to impregnate a γ-Al2O3 support for 3-5 hours. The solution is then dried at 20-30°C for 5-8 hours, followed by drying at 100°C for 6-8 hours. Finally, the temperature is increased to 450-550°C at a rate of 2-6°C / min, and calcined for 6-8 hours to obtain the hydrogenated refining agent.

3. The catalyst for preparing high-density special fuels from high-temperature coal tar according to claim 1, characterized in that, The preparation method of the hydrocracking agent is as follows: Ammonium metatungstate, a tungsten trioxide precursor, and nickel nitrate Ni(NO3)2·6H2O, a nickel monoxide precursor, are added to distilled water according to the concentration ratio. The mixture is stirred at 15~60℃ to completely dissolve the active component solution. Then, the active component solution is used to impregnate the support γ-Al2O3 / Y, with a mass ratio of γ-Al2O3 to Y support of 8:

2. The impregnation is carried out for 3~5h, followed by drying at 20~30℃ for 5~8h, and then drying at 100℃ for 6~8h. Finally, the temperature is increased to 450~550℃ at a heating rate of 2℃ / min~6℃ / min, and calcined for 6~8h to obtain the hydrocracking agent.

4. The catalyst for preparing high-density special fuels from high-temperature coal tar according to claim 1, characterized in that, The preparation method of the hydroisomer is as follows: Ammonium metatungstate, a tungsten trioxide precursor, and nickel nitrate Ni(NO3)2·6H2O, a nickel monoxide precursor, are added to distilled water according to the concentration ratio. The mixture is stirred at 15~60℃ to completely dissolve the active component solution. Then, the active component solution is used to impregnate the support γ-Al2O3 / SAPO-11, with a mass ratio of γ-Al2O3 to SAPO-11 of 8:

2. The impregnation is carried out for 3~5 hours, followed by drying at 20~30℃ for 5~8 hours and then drying at 100℃ for 6~8 hours. Finally, the temperature is increased to 450~550℃ at a heating rate of 2℃ / min~6℃ / min and calcined for 6~8 hours to obtain the hydroisomer.

5. The catalyst for preparing high-density special fuels from high-temperature coal tar according to claim 1, characterized in that, The bird's nest-shaped hydrogenation protective agent has a size of Φ(6~45)mm×(6~15)mm, a porosity of 60%~70%, and a specific surface area of ​​800m². 2 / g~2000m 2 / g; The Mo-Ni hydrogenation protectant is a Mo-Ni / γ-Al2O3 protectant, in which the active component, calculated as 0.7-3.1% MoO3 oxide and 1.3-4% NiO, is present; The Mo-Ni hydrogenation protectant is four-bladed, with a size of Φ(1.7-8.0)mm×(3-10)mm and a bulk ratio of 0.43g / cm³. 3 ~0.80g / cm 3 ; Specific surface area is 100m² 2 / g~150m 2 / g; pore volume 0.3cm 3 / g~0.7cm 3 / g.

6. The catalyst for preparing high-density special fuels from high-temperature coal tar according to claim 1, characterized in that, The Mo-Ni hydrogenated concentrate is clover-shaped, measuring Φ(1.8~3.5)mm×(3~8)mm, with a bulk density of 0.65g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~300m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g; W-Ni hydrocracking agent is in bar shape, with dimensions of Φ(2.0~3.5)mm×(3~8)mm, and a bulk density of 0.65g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~350m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g; The W-Ni hydroisomer is in bar shape, measuring Φ(2.0~3.5)mm×(3~8)mm, with a bulk density of 0.65g / cm³. 3 ~0.90g / cm 3 ; Specific surface area is 60m² 2 / g~350m 2 / g; pore volume 0.3cm 3 / g~0.8cm 3 / g.

7. A method for grading a catalyst for preparing high-density special fuels from high-temperature coal tar according to any one of claims 1 to 6, characterized in that, The following catalysts are sequentially loaded along the material flow direction in the reactor: (1) bird's nest-shaped hydrogenation protectant, with a loading ratio of 4-10%; (2) Mo-Ni / γ-Al2O3 protectant, with a loading ratio of 10-16%; (3) W-Mo-Ni / γ-Al2O3 hydrogenation refining catalyst, with a loading ratio of 25-50%; (4) W-Ni / γ-Al2O3 / Y hydrocracking catalyst, with a loading ratio of 15-30%; (5) W-Ni / γ-Al2O3 / SAPO-11 hydroisomerization catalyst, with a loading ratio of 10-30%. Inert ceramic balls are filled at the top and bottom of the catalyst, with a loading ratio of 5%-10% of the reactor volume. The inert ceramic balls have high mechanical strength and can provide stable support for the catalyst.

8. The application of the catalyst according to any one of claims 1 to 6 in the preparation of high-density special fuels from high-temperature coal tar.

9. The application according to claim 8, characterized in that: A fixed-bed reactor is used to remove sulfur, nitrogen, oxygen, metal impurities and olefins from high-temperature coal tar through catalyst gradation in each bed of the reactor. Aromatic saturation, cracking and isomerization are carried out to purify the coal tar, improve the oil quality and prepare high-density special fuels. The high-temperature coal tar is the <360℃ high-temperature coal tar fraction, that is, the high-temperature coal tar fraction oil after removing the asphalt components.

10. The application according to claim 9, characterized in that: First, in a fixed-bed reactor, the catalyst is sequentially loaded from top to bottom with a bird's nest-shaped hydroprotectant, a Mo-Ni hydroprotectant, a W-Mo-Ni hydrorefining agent, a W-Ni hydrocracking agent, and a W-Ni hydroisomerizing agent. Inert ceramic balls are filled at the top and bottom of the catalyst, respectively. The catalyst is placed in the central isothermal zone of the reactor. The pipeline is sealed and leak-checked. Then, the catalyst is sulfided using CS2 kerosene solution as the sulfiding liquid. The temperature is raised to 300℃~370℃ under a hydrogen pressure of 2.0MPa~4.0MPa, and the volume hourly space velocity is set to 0.2h. -1 ~0.5 h -1 Under conditions of a hydrogen-to-oil ratio of 600-1200, continuous sulfidation is carried out for 24-48 hours. After sulfidation, once the temperature has dropped to room temperature, the feed line is switched to raise the temperature to 320-380℃, and coal tar feedstock is pumped in at 4-8 MPa, with a hydrogen-to-oil volume ratio of 800-1500 and a liquid hourly space velocity of 0.1 h⁻¹. -1 ~0.3 h -1 Under certain conditions, a hydrogenation reaction is carried out. After 24 hours of reaction, the oil product is obtained. The 190℃~300℃ fraction is then cut to obtain the high-density special fuel.

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