Method for preparing aviation kerosene by step-by-step hydrogenation of medium-low temperature coal tar

Abstract

The application discloses a method for preparing aviation kerosene by step-by-step hydrogenation of medium and low temperature coal tar, which adopts a combined process of pre-fractionation, suspension bed and fixed bed. After the whole fraction of medium and low temperature coal tar is preliminarily separated by a feed gas-liquid separation tank, the light component at the top is introduced into a subsequent separation system, the anthracene oil fraction at the side line is introduced into a two-stage hydrogenation cracking reactor as a hydrogen-donor solvent, and the heavy component at the bottom is introduced into a raw material tank as the raw material of the first-stage hydrogenation cracking reactor. The suspension bed hydrogenation cracking is provided with two-stage reactors, the product of the first-stage hydrogenation cracking reactor is introduced into the two-stage hydrogenation cracking reactor for deep hydrogenation cracking after preliminary gas-liquid separation, the anthracene oil separated from the hydrogen-donor solvent raw material and the externally supplemented hydrogen-donor solvent are added to the inlet of the two-stage hydrogenation cracking reactor to promote the hydrogenation cracking of heavy components, and a pressurizing pump and a heating furnace are additionally arranged at the inlet of the reactor. The method can reduce the gas yield in the reaction process, improve the liquid product yield, reduce the coking risk of the device and prolong the operation cycle of the device.

Description

Technical Field

[0001] This invention relates to the field of coal tar hydrogenation technology, specifically to a method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar. Background Technology

[0002] Medium- and low-temperature coal tar is an important byproduct produced during coal coking and gasification, and its production has been increasing with the development of the coking industry and coal chemical industry. Medium- and low-temperature coal tar contains abundant aromatic hydrocarbons, cycloalkanes, and some oxygen-containing compounds. These compounds have high energy density and good combustion performance, making them important raw materials for the preparation of high-quality fuel oil.

[0003] Hydrogenation technology is an effective method for upgrading coal tar. Through hydrogenation, impurities and polycyclic aromatic hydrocarbons can be removed from coal tar, improving its physicochemical properties and increasing its added value. Hydrogenated medium- and low-temperature coal tar exhibits significantly reduced sulfur content, improved viscosity, and enhanced stability, fully meeting the requirements for feedstock in aviation kerosene. Therefore, converting medium- and low-temperature coal tar into aviation kerosene through hydrogenation technology not only achieves efficient utilization of coal tar but also meets the demand of the aviation kerosene market for high-quality fuel.

[0004] CN10864174913B discloses a hydrogenation combined process for producing high-quality fuels from medium- and low-temperature coal tar. The medium- and low-temperature coal tar is distilled through a hydrothermal cracking unit, a first atmospheric distillation unit, a hydrorefining unit, a vacuum distillation unit, a diesel and wax oil hydromodification unit, a wax oil hydrocracking unit, a gasoline and diesel precious metal hydrogenation unit, and a fourth atmospheric distillation unit to obtain the final product.

[0005] The aforementioned patent has the following problems: First, the entire fraction of medium- and low-temperature coal tar is not pre-separated, and the light components in the medium- and low-temperature coal tar directly enter the hydrocracking unit, resulting in excessive cracking of the light components in the reactor, generating a large amount of gas and reducing the yield of liquid products. Second, the light and heavy components in the entire fraction of medium- and low-temperature coal tar have significant differences in properties. During the reaction, the light components are prone to cracking, while the heavy components are prone to condensation, leading to phase separation during the reaction. This further promotes the condensation and coking of the heavy components, clogging the reactor bed and reducing the operating cycle of the unit. Third, the medium- and low-temperature coal tar, especially the heavy components, only undergoes one hydrocracking reaction, resulting in limited improvement in the yield of liquid products. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for producing aviation kerosene by stepwise hydrogenation of medium and low temperature coal tar. This method can reduce the gas yield in the reaction process, increase the liquid product yield, reduce the risk of coking in the equipment, and extend the operating cycle of the equipment.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar includes the following steps;

[0009] a) The raw materials are initially separated in the feed gas-liquid separator S8. The light components at the top of the feed gas-liquid separator S8 enter the first-stage gas-liquid separator S1, and the bottom products enter the feed tank V1. The anthracene oil fraction at 300℃-350℃ is separated from the side stream of the feed gas-liquid separator S8 and enters the second-stage hydrocracking reactor R2 as a hydrogen supply solvent.

[0010] After the medium- and low-temperature coal tar heavy components (bottom product of S8), catalyst, additives, and sulfur supplement are fully mixed in the feed tank V1, they are pressurized by the first-stage high-pressure feed pump P1 and heated by the first-stage feed heater H1, and then mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the first-stage hydrocracking reactor R1 and undergoes a series of chemical reactions under the action of catalyst and hydrogen.

[0011] b) The top product of the first-stage hydrocracking reactor R1 enters the first-stage gas-liquid separator S1, where the product is initially separated into gaseous and liquid components. The gaseous components are mixed with other light components and then enter the second-stage gas-liquid separator S5. The liquid components are mixed with the hydrogen supply solvent B9, pressurized by the second-stage high-pressure feed pump P2, heated by the second-stage feed heater H2, and then mixed with recycled hydrogen and fresh hydrogen. The mixture then enters the reactor from the bottom of the second-stage hydrocracking reactor R2 for further hydrocracking reaction.

[0012] c) The top product of the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the buffer tank V2.

[0013] d) The material in buffer tank V2 is heated by vacuum furnace H3 and then enters vacuum tower S4. The first and second vacuum lines are mixed with other light components and then enter the secondary gas-liquid separator S5. The third vacuum line is completely returned to raw material tank V1. Part of the bottom oil is returned to raw material tank V1 and part is thrown out as solid fuel B8.

[0014] e) The gas components in the secondary gas-liquid separator S5 are mixed with the gas at the top of the atmospheric pressure tower S6 and then enter the tertiary gas-liquid separator S7; the liquid components in the secondary gas-liquid separator S5 are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump P3, heated by the tertiary feed heater H4, and then enter the fixed bed hydrogenation reactor R3 from the top.

[0015] f) The liquid component in the three-stage gas-liquid separator S7 is discharged as light hydrocarbon component B6; part of the gas component in the three-stage gas-liquid separator S7 is discharged as hydrogen B5, and part is compressed by the circulating hydrogen compressor C1 and returned as a hydrogen source for the first-stage hydrocracking reactor R1, the second-stage hydrocracking reactor R2, the fixed-bed hydrocracking reactor R3 and the jet fuel hydrocracking reactor R4.

[0016] g) The bottom product of the fixed bed hydrogenation reactor R3 enters the atmospheric tower S6, the top gas of the atmospheric tower enters the three-stage gas-liquid separator S7, the first atmospheric tower line is used as the naphtha fraction B2 exit unit, the third atmospheric tower line is used as the diesel fraction B3 exit unit, the fourth atmospheric tower line is used as the wax oil fraction B4 exit unit, and the atmospheric residue oil at the bottom of the atmospheric tower S6 is returned to the feed tank V1.

[0017] h) The atmospheric distillation column S6 contains aviation kerosene fraction. After being mixed with new hydrogen and recycled hydrogen, it is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the aviation kerosene hydrogenation reactor R4 from the top. The product is discharged from the bottom as aviation kerosene B7.

[0018] The primary hydrocracking reactor R1 and the secondary hydrocracking reactor R2 are suspended bed reactors, both with an empty barrel structure and no internal components. This design minimizes the flow resistance and dead zones within the reactor, reducing the risk of coking. At the same time, this empty barrel structure design ensures the uniformity and stability of the temperature and flow fields throughout the reactor, avoiding localized overheating and coking.

[0019] Preferably, the operating conditions for the primary hydrocracking reactor R1 are: reaction temperature 450℃-465℃, reaction pressure 16MPa-22MPa, and space velocity 0.3h. -1 -0.8h -1 The hydrogen-to-oil ratio is 500 NL / kg-1500 NL / kg; the operating conditions of the secondary hydrocracking reactor R2 are: reaction temperature 460℃-470℃, reaction pressure 16MPa-22MPa, and space velocity 0.3h / kg. -1 -0.8h -1 Hydrogen-to-oil ratio: 1000 NL / kg - 1500 NL / kg;

[0020] Experimental studies have shown that setting these reaction conditions in the primary hydrocracking reactor can reduce gas yield and coke production while ensuring the conversion efficiency of medium- and low-temperature coal tar. The reaction conditions in the secondary hydrocracking reactor are even more stringent than those in the primary hydrocracking reactor, mainly in terms of reaction temperature, reaction pressure, and hydrogen-to-oil ratio. This is primarily because the feed to the secondary hydrocracking reactor consists of components that were not converted in the primary hydrocracking reactor, making conversion more difficult under conventional conditions. Therefore, the reaction conditions are more stringent, and the addition of hydrogen-supplying solvent further promotes conversion.

[0021] This invention designs two-stage hydrocracking reactors R1 and R2, and sets up a primary gas-liquid separator S1, a secondary high-pressure feed pump P2, and a secondary feed heater H2 between the primary hydrocracking reactor R1 and the secondary hydrocracking reactor R2, while simultaneously supplementing with hydrogen-supplying solvent B9. It has the following two advantages: First, the primary gas-liquid separator S1 separates a large amount of light components produced in the primary hydrocracking reactor R1, avoiding excessive cracking of light components and increasing gas yield. Simultaneously, separating the light components significantly reduces their encroachment on the effective volume of the secondary hydrocracking reactor R2, increasing the actual space velocity. Second, the liquid phase product at the outlet of the primary hydrocracking reactor R1 is a difficult-to-crack product, requiring further increases in the severity of reaction conditions. Therefore, by adding hydrogen-supplying solvent B9, secondary high-pressure feed pump P2, and secondary feed heater H2 at the inlet of the secondary hydrocracking reactor to supplement hydrogen, the degree of cracking of heavy components is further improved, increasing the yield of light oil products.

[0022] The hydrogen-donating solvent B9 is a component rich in aromatic rings and cycloalkane ring structures, including but not limited to anthracene oil, tetrahydronaphthalene, tetrahydrophenanthrene, or mixtures thereof in different proportions, which promotes the lightening reaction in the secondary hydrocracking reactor R2. The amount of hydrogen-donating solvent replenished is 0-25% based on the mass ratio of coal tar feedstock.

[0023] In step a), the raw material is medium-low temperature coal tar, and the catalysts in the primary hydrocracking reactor and the secondary hydrocracking reactor are carbon-supported Fe-based dispersed catalysts with a particle size of less than 75 μm.

[0024] Preferably, to further improve the reaction activity and light oil yield, the catalyst is loaded with 5%-30% Fe, 2%-10% Ni, and 2%-10% Mo by mass ratio.

[0025] In step c), a buffer tank V2 is installed after the hot high-pressure separator S3. The hot high-pressure separator S3 is an intermittent discharge mode. In order to ensure the stable material flow of the fixed bed hydrogenation reactor and the stable operation of the device, a buffer tank is installed at the inlet of the fixed bed hydrogenation reactor.

[0026] In step d), the proportion of the bottom oil from the pressure reducing tower S4 returned to the raw material tank V1 is 0-1, and the proportion of the top gas from the three-stage gas-liquid separator S7 returned as circulating hydrogen is 0-1. The circulating hydrogen is rich in hydrogen and can serve as an important source of hydrogen during the reaction process. At the same time, the circulating hydrogen contains some hydrogen sulfide gas, which is beneficial to the sulfidation of the catalyst during the reaction process.

[0027] In step e), the main purpose of the fixed-bed reactor R3 is to remove impurities from the raw materials. The reactor contains multiple catalyst beds, namely a protective agent, a demetallizing and decarbonizing agent, and a desulfurizing, denitrifying, and deoxidizing agent. The catalyst uses Al2O3 as a support and is loaded with active metals such as Ni, Mo, and W, which have excellent hydrogenation activity. The reaction temperature of the fixed-bed reactor R3 is 350℃-420℃, the reaction pressure is 6MPa-16 MPa, and the space velocity is 0.8h. -1 -3.0h -1 Hydrogen-to-oil ratio: 300 NL / kg - 1200 NL / kg;

[0028] Preferably, the catalyst has a Ni loading of 2%-10%, a Mo loading of 2%-10%, and a W loading of 2%-10% to remove impurities from the raw materials, mainly residual carbon, metals, S, N, O and other heteroatoms.

[0029] In step f), the main purpose of the jet fuel hydrogenation reactor R4 is to perform reactions such as hydroisomerization, selective hydrogenation saturation of aromatics, and selective hydrogenation ring-opening on jet fuel fractions. The catalyst uses Al₂O₃ as a support, loaded with active metals such as Pd, Ni, Mo, and W, which have excellent hydrogenation activity. The reaction temperature of the jet fuel hydrogenation reactor R4 is 350℃-420℃, the reaction pressure is 6MPa-16MPa, and the space velocity is 0.8h⁻¹. -1 -3.0h -1 Hydrogen-to-oil ratio: 300 NL / kg - 1200 NL / kg;

[0030] Preferably, the catalyst has a Ni loading of 2%-10%, a Mo loading of 2%-10%, a W loading of 2%-10%, and a Pd loading of 2%-10%; it performs hydroisomerization, selective aromatic hydrogenation saturation, and selective hydrogenation ring-opening reactions on the jet fuel fraction to maximize the production of jet fuel components.

[0031] In step g), gasoline and diesel fractions are co-produced in atmospheric tower S6 via atmospheric line 1 and atmospheric line 3.

[0032] The beneficial effects of this invention are:

[0033] This invention reduces the gas yield during the reaction process, increases the liquid product yield, reduces the risk of coking in the equipment, and extends the operating cycle of the equipment.

[0034] This invention employs a combined process of pre-fractionation, suspended bed, and fixed bed. After initial separation in the feed gas-liquid separator S8, the top light fraction enters the subsequent separation system, while the side-stream anthracene oil fraction enters the secondary hydrocracking reactor R2 as a hydrogen-supplying solvent. The bottom heavy fraction enters the feed tank V1 as the feedstock for the primary hydrocracking reactor R1. The suspended bed hydrocracking process consists of two reactors. The product from the primary hydrocracking reactor R1, after initial gas-liquid separation, enters the secondary hydrocracking reactor R2 for deep hydrocracking. The inlet of the secondary hydrocracking reactor R2 is supplemented with anthracene oil separated from the feedstock and externally added hydrogen-supplying solvent to promote the hydrocracking of heavy components. Simultaneously, a pressure pump and a heater are added at the reactor inlet to increase reaction pressure and temperature, improve conversion rate, and increase liquid product yield. The fixed bed hydrocracking process consists of two reactors: a fixed bed hydrorefining reactor and a jet fuel hydrocracking reactor, maximizing jet fuel production while simultaneously producing gasoline and diesel as byproducts. This combined process can reduce the gas yield during the reaction, increase the liquid product yield, reduce the risk of coking in the unit, and extend the unit's operating cycle. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of a method for producing aviation kerosene from medium- and low-temperature coal tar through stepwise hydrogenation according to the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] R1 - First-stage hydrocracking reactor; R2 - Second-stage hydrocracking reactor; R3 - Fixed-bed hydrocracking reactor; R4 - Aviation kerosene hydrocracking reactor; V1 - Feed tank; V2 - Buffer tank; S1 - First-stage gas-liquid separator; S2 - Hot high-pressure separator; S3 - Hot low-pressure separator; S4 - Vacuum reducing tower; S5 - Second-stage gas-liquid separator; S6 - Atmospheric pressure tower; S7 - Third-stage gas-liquid separator; S8 - Feed gas-liquid separator; H1 - First-stage feed heater; H2 - Second-stage feed heater. Feed heating furnace; H3 - vacuum furnace; H4 - three-stage feed heating furnace; H5 - four-stage feed heating furnace; P1 - first-stage high-pressure feed pump; P2 - second-stage high-pressure feed pump; P3 - third-stage high-pressure feed pump; P4 - four-stage high-pressure feed pump; C1 - circulating hydrogen compressor; B1 - fresh hydrogen; B2 - naphtha fraction; B3 - diesel fraction; B4 - wax oil fraction; B5 - hydrogen exhaust; B6 - light hydrocarbon component; B7 - aviation kerosene; B8 - solid fuel; B9 - hydrogen supply solvent. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments.

[0039] Example 1

[0040] After separation in the feed gas-liquid separator S8, the light components of the medium- and low-temperature coal tar enter the primary gas-liquid separator S1. Anthracene oil at 300℃-350℃ is drawn off via a side stream and enters the secondary hydrocracking reactor R2. The heavy components at the bottom enter the feed tank V1, where they are thoroughly mixed with 1% catalyst, 0.5% additive, and 0.5% sulfur supplement. After being pressurized by the primary high-pressure feed pump P1 and heated by the primary feed heater H1, the mixture is mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the primary hydrocracking reactor and undergoes a series of chemical reactions under the action of the catalyst and hydrogen. The reaction temperature is 450℃, the pressure is 16 MPa, and the space velocity is 0.3 h⁻¹. -1 The hydrogen-to-oil ratio is 500 NL / kg. The top product from the primary hydrocracking reactor R1 enters the primary gas-liquid separator S1, where it is initially separated into gaseous and liquid components. The gaseous component, after being mixed with other light components, enters the secondary gas-liquid separator S5. The liquid component, mixed with hydrogen-supplying solvent B9 (0% addition), is pressurized by the secondary high-pressure feed pump P2 and heated by the secondary feed heater H2. It is then mixed with recycled hydrogen and fresh hydrogen and enters the secondary hydrocracking reactor R2 from the bottom for further hydrocracking. The reaction temperature is 460℃, the pressure is 20 MPa, and the space velocity is 0.5 h⁻¹. -1The hydrogen-to-oil ratio is 1000 NL / kg. The top product from the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5, while the liquid component enters the buffer tank V2. The material in the buffer tank V2 is heated by the vacuum furnace H3 and then enters the vacuum tower S4. The first and second vacuum lines mix with other light components and then enter the secondary gas-liquid separator S5. The entire third vacuum line is returned to the feed tank V1, and the bottom oil is also returned to the feed tank V1. The gaseous components in the secondary gas-liquid separator S5 are then separated by the atmospheric pressure tower. The gas at the top of S6 mixes and enters the tertiary gas-liquid separator S7; the liquid component in the secondary gas-liquid separator S5 mixes with fresh hydrogen and recycled hydrogen, is pressurized by the tertiary high-pressure feed pump P3, and heated by the tertiary feed heater H4 before entering the fixed-bed hydrogenation reactor R3 from the top. The reaction temperature is 350℃, the reaction pressure is 6MPa, the space velocity is 0.8h-1, and the hydrogen-to-oil ratio is 300NL / kg; the liquid component in the tertiary gas-liquid separator S7 exits the device as light hydrocarbon component B6; 20% of the gas component in the tertiary gas-liquid separator S7 exits the device as hydrogen discharge B5, and 80% is compressed by the recycled hydrogen compressor C1 and returned as a hydrogen source for the primary hydrocracking reactor R1, the secondary hydrocracking reactor R2, the fixed-bed hydrogenation reactor R3, and the jet fuel hydrogenation reactor R4. The bottom product of the fixed-bed hydrotreating reactor R3 enters the atmospheric distillation tower S6, and the top gas from the atmospheric distillation tower enters the three-stage gas-liquid separator S7. The first atmospheric distillation line (Standard Line 1) is used as the outlet for naphtha fraction B2, the third atmospheric distillation line (Standard Line 3) is used as the outlet for diesel fraction B3, and the fourth atmospheric distillation line (Standard Line 4) is used as the outlet for wax oil fraction B4. The atmospheric residue at the bottom of the atmospheric distillation tower S6 is returned to the feed tank V1. The second atmospheric distillation line in the atmospheric distillation tower S6 contains jet fuel fraction, which, after mixing with fresh hydrogen and recycled hydrogen, is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the jet fuel hydrotreating reactor R4 from the top. The reaction temperature is 360℃, the reaction pressure is 7MPa, and the space velocity is 1.0 h⁻¹. -1 The hydrogen-to-oil ratio is 500 NL / kg, and the product is discharged from the bottom as aviation kerosene B7. The unit operates stably, and the product meets the requirements for navigation.

[0041] Example 2

[0042] After separation in the feed gas-liquid separator S8, the light components of the medium- and low-temperature coal tar enter the primary gas-liquid separator S1. Anthracene oil at 300℃-350℃ is drawn from the side stream and enters the secondary hydrocracking reactor R2. The heavy components at the bottom enter the feed tank V1, where they are thoroughly mixed with 1% catalyst, 0.5% additive, and 0.5% sulfur supplement. After being pressurized by the primary high-pressure feed pump P1 and heated by the primary feed heater H1, the mixture is mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the primary hydrocracking reactor and undergoes a series of chemical reactions under the action of the catalyst and hydrogen. The reaction temperature is 455℃, the pressure is 17 MPa, and the space velocity is 0.35 h⁻¹. -1 The hydrogen-to-oil ratio is 600 NL / kg. The top product from the primary hydrocracking reactor R1 enters the primary gas-liquid separator S1, where it is initially separated into gaseous and liquid components. The gaseous component, after being mixed with other light components, enters the secondary gas-liquid separator S5. The liquid component, after being mixed with 25% hydrogen-donating solvent B9 anthracene oil, is pressurized by the secondary high-pressure feed pump P2 and heated by the secondary feed heater H2. It is then mixed with recycled hydrogen and fresh hydrogen and enters the secondary hydrocracking reactor R2 from the bottom for further hydrocracking. The reaction temperature is 465℃, the pressure is 20 MPa, and the space velocity is 0.6 h⁻¹. -1The hydrogen-to-oil ratio is 1200 NL / kg. The top product from the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5, while the liquid component enters the buffer tank V2. The material in the buffer tank V2 is heated by the vacuum furnace H3 and then enters the vacuum tower S4. The first and second vacuum lines mix with other light components and then enter the secondary gas-liquid separator S5. All of the third vacuum line is returned to the feed tank V1, and 50% of the bottom oil is returned to the feed tank V1, while the remaining 50% is discharged as solid fuel B8. In the secondary gas-liquid separator S5... The gaseous components are mixed with the gas at the top of the atmospheric pressure tower S6 and then enter the tertiary gas-liquid separator S7. The liquid components in the secondary gas-liquid separator S5 are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump P3, and heated by the tertiary feed heater H4 before entering the fixed-bed hydrogenation reactor R3 from the top. The reaction temperature is 350℃, the reaction pressure is 7MPa, the space velocity is 1h-1, and the hydrogen-to-oil ratio is 500NL / kg. The liquid components in the tertiary gas-liquid separator S7 are discharged as light hydrocarbon components B6. 40% of the gaseous components in the tertiary gas-liquid separator S7 are discharged as hydrogen B5, and 60% are compressed by the recycled hydrogen compressor C1 and returned as a hydrogen source for the primary hydrocracking reactor R1, the secondary hydrocracking reactor R2, the fixed-bed hydrogenation reactor R3, and the jet fuel hydrogenation reactor R4. The bottom product of the fixed-bed hydrotreating reactor R3 enters the atmospheric distillation tower S6, and the top gas from the atmospheric distillation tower enters the three-stage gas-liquid separator S7. The first atmospheric distillation line serves as the outlet for naphtha fraction B2, the third atmospheric distillation line serves as the outlet for diesel fraction B3, and the fourth atmospheric distillation line serves as the outlet for wax oil fraction B4. The atmospheric residue at the bottom of the atmospheric distillation tower S6 is returned to the feed tank V1. The second atmospheric distillation line in the atmospheric distillation tower S6 contains jet fuel fraction, which, after mixing with fresh hydrogen and recycled hydrogen, is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the jet fuel hydrotreating reactor R4 from the top. The reaction temperature is 370℃, the reaction pressure is 8MPa, and the space velocity is 1.2h / h. -1 The hydrogen-to-oil ratio is 700 NL / kg, and the product is discharged from the bottom as aviation kerosene B7, which meets the requirements for navigation.

[0043] Example 3

[0044] After separation in the feed gas-liquid separator S8, the light components of the medium- and low-temperature coal tar enter the primary gas-liquid separator S1. Anthracene oil at 300℃-350℃ is drawn from the side stream and enters the secondary hydrocracking reactor R2. The heavy components at the bottom enter the feed tank V1, where they are thoroughly mixed with 1% catalyst, 0.5% additive, and 0.5% sulfur supplement. After being pressurized by the primary high-pressure feed pump P1 and heated by the primary feed heater H1, the mixture is mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the primary hydrocracking reactor and undergoes a series of chemical reactions under the action of the catalyst and hydrogen. The reaction temperature is 460℃, the pressure is 20 MPa, and the space velocity is 0.5 h⁻¹. -1 The hydrogen-to-oil ratio is 1000 NL / kg. The top product from the primary hydrocracking reactor R1 enters the primary gas-liquid separator S1, where it is initially separated into gaseous and liquid components. The gaseous component, after being mixed with other light components, enters the secondary gas-liquid separator S5. The liquid component, after being mixed with 5% hydrogen-donating solvent B9 tetrahydronaphthalene, is pressurized by the secondary high-pressure feed pump P2 and heated by the secondary feed heater H2. It is then mixed with recycled hydrogen and fresh hydrogen and enters the secondary hydrocracking reactor R2 from the bottom for further hydrocracking. The reaction temperature is 470℃, the pressure is 21 MPa, and the space velocity is 0.7 h⁻¹. -1The hydrogen-to-oil ratio is 1500 NL / kg. The top product from the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5, while the liquid component enters the buffer tank V2. The material in the buffer tank V2 is heated by the vacuum furnace H3 and then enters the vacuum tower S4. The first and second vacuum lines mix with other light components and then enter the secondary gas-liquid separator S5. All of the third vacuum line is returned to the feed tank V1, 20% of the bottom oil is returned to the feed tank V1, and 80% is discharged externally as solid fuel B8. In the secondary gas-liquid separator S5... The gaseous components are mixed with the gas at the top of the atmospheric pressure tower S6 and then enter the tertiary gas-liquid separator S7. The liquid components in the secondary gas-liquid separator S5 are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump P3, and heated by the tertiary feed heater H4 before entering the fixed-bed hydrogenation reactor R3 from the top. The reaction temperature is 360℃, the reaction pressure is 8MPa, the space velocity is 1.4h-1, and the hydrogen-to-oil ratio is 800NL / kg. The liquid components in the tertiary gas-liquid separator S7 are discharged as light hydrocarbon components B6. 50% of the gaseous components in the tertiary gas-liquid separator S7 are discharged as hydrogen B5, and 50% are compressed by the recycled hydrogen compressor C1 and returned as a hydrogen source for the primary hydrocracking reactor R1, the secondary hydrocracking reactor R2, the fixed-bed hydrogenation reactor R3, and the jet fuel hydrogenation reactor R4. The bottom product of the fixed-bed hydrotreating reactor R3 enters the atmospheric distillation tower S6, and the top gas from the atmospheric distillation tower enters the three-stage gas-liquid separator S7. The first atmospheric distillation line serves as the outlet for naphtha fraction B2, the third atmospheric distillation line serves as the outlet for diesel fraction B3, and the fourth atmospheric distillation line serves as the outlet for wax oil fraction B4. The atmospheric residue at the bottom of the atmospheric distillation tower S6 is returned to the feed tank V1. The second atmospheric distillation line in the atmospheric distillation tower S6 contains jet fuel fraction, which, after mixing with fresh hydrogen and recycled hydrogen, is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the jet fuel hydrotreating reactor R4 from the top. The reaction temperature is 370℃, the reaction pressure is 10MPa, and the space velocity is 1.6h / h. -1 The hydrogen-to-oil ratio is 1000 NL / kg, and the product is discharged from the bottom as aviation kerosene B7, which meets the requirements for navigation.

[0045] Example 4

[0046] After separation in the feed gas-liquid separator S8, the light components of the medium- and low-temperature coal tar enter the primary gas-liquid separator S1. Anthracene oil at 300℃-350℃ is drawn from the side stream and enters the secondary hydrocracking reactor R2. The heavy components at the bottom enter the feed tank V1, where they are thoroughly mixed with 1% catalyst, 0.5% additive, and 0.5% sulfur supplement. After being pressurized by the primary high-pressure feed pump P1 and heated by the primary feed heater H1, the mixture is mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the primary hydrocracking reactor and undergoes a series of chemical reactions under the action of the catalyst and hydrogen. The reaction temperature is 460℃, the pressure is 19 MPa, and the space velocity is 0.8 h⁻¹. -1 The hydrogen-to-oil ratio is 1500 NL / kg. The top product from the primary hydrocracking reactor R1 enters the primary gas-liquid separator S1, where it is initially separated into gaseous and liquid components. The gaseous component, after being mixed with other light components, enters the secondary gas-liquid separator S5. The liquid component, after being mixed with 5% hydrogen-supplying solvent B9 tetrahydrophenanthrene, is pressurized by the secondary high-pressure feed pump P2 and heated by the secondary feed heater H2. It is then mixed with recycled hydrogen and fresh hydrogen and enters the secondary hydrocracking reactor R2 from the bottom for further hydrocracking. The reaction temperature is 470℃, the pressure is 22 MPa, and the space velocity is 0.8 h⁻¹. -1The hydrogen-to-oil ratio is 1500 NL / kg. The top product from the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component mixes with other light components and then enters the secondary gas-liquid separator S5, while the liquid component enters the buffer tank V2. The material in the buffer tank V2 is heated by the vacuum furnace H3 and then enters the vacuum tower S4. The first and second vacuum lines mix with other light components and then enter the secondary gas-liquid separator S5. All of the third vacuum line is returned to the feed tank V1, 30% of the bottom oil is returned to the feed tank V1, and 70% is discharged externally as solid fuel B8. The product in the secondary gas-liquid separator S5... The gaseous components are mixed with the gas at the top of the atmospheric pressure tower S6 and then enter the tertiary gas-liquid separator S7. The liquid components in the secondary gas-liquid separator S5 are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump P3, and heated by the tertiary feed heater H4 before entering the fixed-bed hydrogenation reactor R3 from the top. The reaction temperature is 380℃, the reaction pressure is 10MPa, the space velocity is 1.8h-1, and the hydrogen-to-oil ratio is 1000NL / kg. The liquid components in the tertiary gas-liquid separator S7 are discharged as light hydrocarbon components B6. 80% of the gaseous components in the tertiary gas-liquid separator S7 are discharged as hydrogen B5, and 20% are compressed by the recycled hydrogen compressor C1 and returned as a hydrogen source for the primary hydrocracking reactor R1, the secondary hydrocracking reactor R2, the fixed-bed hydrogenation reactor R3, and the jet fuel hydrogenation reactor R4. The bottom product of the fixed-bed hydrotreating reactor R3 enters the atmospheric distillation tower S6, and the top gas from the atmospheric distillation tower enters the three-stage gas-liquid separator S7. The first atmospheric distillation line (Standard Line 1) is used as the outlet for naphtha fraction B2, the third atmospheric distillation line (Standard Line 3) is used as the outlet for diesel fraction B3, and the fourth atmospheric distillation line (Standard Line 4) is used as the outlet for wax oil fraction B4. The atmospheric residue at the bottom of the atmospheric distillation tower S6 is returned to the feed tank V1. The second atmospheric distillation line in the atmospheric distillation tower S6 contains jet fuel fraction, which, after mixing with fresh hydrogen and recycled hydrogen, is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the jet fuel hydrotreating reactor R4 from the top. The reaction temperature is 400℃, the reaction pressure is 12MPa, and the space velocity is 2.0h⁻¹. -1 The hydrogen-to-oil ratio is 1200 NL / kg, and the product is discharged from the bottom as aviation kerosene B7, which meets the requirements for navigation.

[0047] Example 5

[0048] After separation in the feed gas-liquid separator S8, the light components of the medium- and low-temperature coal tar enter the primary gas-liquid separator S1. Anthracene oil at 300℃-350℃ is drawn from the side stream and enters the secondary hydrocracking reactor R2. The heavy components at the bottom enter the feed tank V1, where they are thoroughly mixed with 1% catalyst, 0.5% additive, and 0.5% sulfur supplement. After being pressurized by the primary high-pressure feed pump P1 and heated by the primary feed heater H1, the mixture is mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the primary hydrocracking reactor and undergoes a series of chemical reactions under the action of the catalyst and hydrogen. The reaction temperature is 455℃, the pressure is 18 MPa, and the space velocity is 0.8 h⁻¹. -1 The hydrogen-to-oil ratio is 1200 NL / kg. The top product from the primary hydrocracking reactor R1 enters the primary gas-liquid separator S1, where it is initially separated into gaseous and liquid components. The gaseous component, after being mixed with other light components, enters the secondary gas-liquid separator S5. The liquid component, after being mixed with 12% hydrogen-donating solvent B92% tetrahydronaphthalene + 2% tetrahydrophenanthrene + 8% anthracene oil, is pressurized by the secondary high-pressure feed pump P2 and heated by the secondary feed heater H2. It is then mixed with recycled hydrogen and fresh hydrogen and enters the secondary hydrocracking reactor R2 from the bottom for further hydrocracking. The reaction temperature is 468℃, the pressure is 21 MPa, and the space velocity is 0.9 h⁻¹. -1The hydrogen-to-oil ratio is 1200 NL / kg. The top product from the secondary hydrocracking reactor R2 enters the hot high-pressure separator S2 for preliminary gas-liquid separation. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator S5. The liquid component enters the hot low-pressure separator S3 for further separation into gaseous and liquid components. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator S5, while the liquid component enters the buffer tank V2. The material in the buffer tank V2 is heated by the vacuum furnace H3 and then enters the vacuum tower S4. The first and second vacuum lines are mixed with other light components and then enter the secondary gas-liquid separator S5. All of the third vacuum line is returned to the feed tank V1, and 40% of the bottom oil is returned to the feed tank V1, while 60% is discharged externally as solid fuel B8. The product in the secondary gas-liquid separator S5... The gaseous components are mixed with the gas at the top of the atmospheric pressure tower S6 and then enter the tertiary gas-liquid separator S7. The liquid components in the secondary gas-liquid separator S5 are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump P3, and heated by the tertiary feed heater H4 before entering the fixed-bed hydrogenation reactor R3 from the top. The reaction temperature is 370℃, the reaction pressure is 9MPa, the space velocity is 1.2h-1, and the hydrogen-to-oil ratio is 1200NL / kg. The liquid components in the tertiary gas-liquid separator S7 are discharged as light hydrocarbon components B6. 60% of the gaseous components in the tertiary gas-liquid separator S7 are discharged as hydrogen B5, and 40% are compressed by the recycled hydrogen compressor C1 and returned as a hydrogen source for the primary hydrocracking reactor R1, the secondary hydrocracking reactor R2, the fixed-bed hydrogenation reactor R3, and the jet fuel hydrogenation reactor R4. The bottom product of the fixed-bed hydrotreating reactor R3 enters the atmospheric distillation tower S6, and the top gas from the atmospheric distillation tower enters the three-stage gas-liquid separator S7. The first atmospheric distillation line serves as the outlet for naphtha fraction B2, the third atmospheric distillation line serves as the outlet for diesel fraction B3, and the fourth atmospheric distillation line serves as the outlet for wax oil fraction B4. The atmospheric residue at the bottom of the atmospheric distillation tower S6 is returned to the feed tank V1. The second atmospheric distillation line in the atmospheric distillation tower S6 contains jet fuel fraction, which, after mixing with fresh hydrogen and recycled hydrogen, is pressurized by the four-stage high-pressure feed pump P4 and heated by the four-stage feed heater H5 before entering the jet fuel hydrotreating reactor R4 from the top. The reaction temperature is 420℃, the reaction pressure is 16MPa, and the space velocity is 1.8h / h. -1 The hydrogen-to-oil ratio is 1200 NL / kg, and the product is discharged from the bottom as aviation kerosene B7. The unit operates stably, and the product meets the requirements for navigation.

[0049] Properties of medium and low temperature coal tar

[0050] project unit numerical values Density at 20℃ g / cm3 1.013 Viscosity 80℃, mm2 / s 8.9834 Toluene-insoluble matter (TI) wt% 1.05 Moisture wt% 4.03 Carbon residue wt% 5.08 Ash wt% 0.13 C wt% 85.32 H wt% 8.67 S wt% 0.18 N wt% 1.35 O wt% 5.11 Hydrogen-to-carbon ratio - 1.22 Saturated fraction wt% 18.31 Aromatic components wt% 22.12 gelatinous wt% 45.44 Asphalt wt% 14.13

Claims

1. A method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar, characterized in that, Includes the following steps; a) The feedstock is initially separated in the feed gas-liquid separator (S8). The light components from the top of the feed gas-liquid separator (S8) enter the first-stage gas-liquid separator (S1), while the heavy components of the medium- and low-temperature coal tar enter the feed tank (V1). The anthracene oil fraction at 300℃-350℃ is separated from the side stream of the feed gas-liquid separator (S8) and used as a hydrogen-donating solvent to enter the second-stage hydrocracking reactor (R2). After the medium- and low-temperature coal tar heavy components, catalysts, additives, and sulfur supplements are fully mixed in the feed tank (V1), they are pressurized by the first-stage high-pressure feed pump (P1) and heated by the first-stage feed heater (H1) and then mixed with fresh hydrogen and recycled hydrogen. The mixture enters from the bottom of the first-stage hydrocracking reactor (R1) and undergoes a series of chemical reactions under the action of catalysts and hydrogen. b) The top product of the first-stage hydrocracking reactor (R1) enters the first-stage gas-liquid separator (S1), where the product is initially separated into gaseous and liquid components. The gaseous components are mixed with other light components and then enter the second-stage gas-liquid separator (S5). The liquid components are mixed with the hydrogen-supplying solvent (B9), pressurized by the second-stage high-pressure feed pump (P2), heated by the second-stage feed heater (H2), and then mixed with recycled hydrogen and fresh hydrogen. The mixture then enters the reactor from the bottom of the second-stage hydrocracking reactor (R2) for further hydrocracking reaction. c) The top product of the secondary hydrocracking reactor (R2) enters the hot high-pressure separator (S2) for preliminary gas-liquid separation. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator (S5). The liquid component enters the hot low-pressure separator (S3) for further separation into gaseous and liquid components. The gaseous component is mixed with other light components and then enters the secondary gas-liquid separator (S5). The liquid component enters the buffer tank (V2). d) The material in the buffer tank (V2) is heated by the vacuum furnace (H3) and then enters the vacuum tower (S4). The first and second vacuum lines are mixed with other light components and then enter the secondary gas-liquid separator (S5). The entire third vacuum line is returned to the feed tank (V1), and part of the bottom oil is returned to the feed tank (V1), while part is thrown out as solid fuel (B8). e) The gas components in the secondary gas-liquid separator (S5) are mixed with the gas at the top of the atmospheric pressure tower (S6) and then enter the tertiary gas-liquid separator (S7); the liquid components in the secondary gas-liquid separator (S5) are mixed with fresh hydrogen and recycled hydrogen, pressurized by the tertiary high-pressure feed pump (P3), heated by the tertiary feed heater (H4), and then enter the fixed bed hydrogenation reactor (R3) from the top. f) The liquid component in the three-stage gas-liquid separator (S7) is discharged as light hydrocarbon component (B6); part of the gas component in the three-stage gas-liquid separator (S7) is discharged as hydrogen effluent (B5), and part is compressed by the circulating hydrogen compressor (C1) and returned as a hydrogen source for the first-stage hydrocracking reactor (R1), the second-stage hydrocracking reactor (R2), the fixed-bed hydrocracking reactor (R3), and the jet fuel hydrocracking reactor (R4). g) The bottom product of the fixed-bed hydrotreating reactor (R3) enters the atmospheric tower (S6), the top gas of the atmospheric tower enters the three-stage gas-liquid separator (S7), the first atmospheric tower line is used as the naphtha fraction (B2) outlet, the third atmospheric tower line is used as the diesel fraction (B3) outlet, the fourth atmospheric tower line is used as the wax oil fraction (B4) outlet, and the atmospheric residue at the bottom of the atmospheric tower (S6) is returned to the feed tank (V1). h) The atmospheric distillation column (S6) contains aviation kerosene fraction. After being mixed with new hydrogen and recycled hydrogen, it is pressurized by a four-stage high-pressure feed pump (P4) and heated by a four-stage feed heater (H5). The product then enters the aviation kerosene hydrogenation reactor (R4) from the top, and the product is discharged from the bottom as aviation kerosene (B7).

2. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, The primary hydrocracking reactor (R1) and the secondary hydrocracking reactor (R2) are both suspended bed reactors with empty barrel structures.

3. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, The operating conditions for the primary hydrocracking reactor (R1) are: reaction temperature 450℃-465℃, reaction pressure 16MPa-22MPa, and space velocity 0.3h / h. -1 -0.8h -1 The hydrogen-to-oil ratio is 500 NL / kg-1500 NL / kg; the operating conditions of the secondary hydrocracking reactor (R2) are: reaction temperature 460℃-470℃, reaction pressure 16MPa-22MPa, and space velocity 0.3h / kg. -1 -0.8h -1 Hydrogen-to-oil ratio: 1000 NL / kg - 1500 NL / kg; A primary gas-liquid separator (S1), a secondary high-pressure feed pump (P2), and a secondary feed heater (H2) are installed between the primary hydrocracking reactor (R1) and the secondary hydrocracking reactor (R2), while a hydrogen supply solvent (B9) is also provided.

4. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, The hydrogen-donating solvent (B9) is a component rich in aromatic and cycloalkane ring structures, including anthracene oil, tetrahydronaphthalene, tetrahydrophenanthrene or mixtures thereof in different proportions, which promotes the lightening reaction in the secondary hydrocracking reactor (R2). The amount of hydrogen-donating solvent added is 0-25% based on the mass ratio of coal tar feedstock.

5. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, In step a), the raw material is medium-low temperature coal tar, and the catalyst is a carbon-supported Fe-based dispersed catalyst with a particle size of less than 75 μm. The catalyst is loaded with 5%-30% Fe, 2%-10% Ni, and 2-10% Mo.

6. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, In step d), the proportion of the bottom oil from the pressure reducing tower (S4) returned to the raw material tank (V1) is 0-1, and the proportion of the gas at the top of the three-stage gas-liquid separator (S7) returned as circulating hydrogen is 0-1.

7. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, In step h), the catalyst is supported on Al2O3 and loaded with Pd, Ni, Mo, and W; the reaction temperature of the jet fuel hydrogenation reactor (R4) is 350℃-420℃, the reaction pressure is 6MPa-16MPa, and the space velocity is 0.8h. -1 -3.0h -1 Hydrogen-to-oil ratio: 300 NL / kg - 1200 NL / kg; The catalyst has a Ni loading of 2%-10%, a Mo loading of 2%-10%, a W loading of 2%-10%, and a Pd loading of 2%-10%.

8. The method for producing aviation kerosene by stepwise hydrogenation of medium- and low-temperature coal tar according to claim 1, characterized in that, In step g), gasoline and diesel fractions are produced simultaneously in atmospheric pressure tower (S6) through atmospheric pressure line 1 and atmospheric pressure line 3.

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