A jet fuel and a method for producing the same

Abstract

This application discloses a method for preparing jet fuel, comprising: pretreating medium- and low-temperature coal tar, wherein the pretreatment includes one or more of delayed coking, hydrorefining, hydrocracking, fluidized bed, slurry bed, and fraction cutting; the pretreated coal tar having S < 1000 ppm, N < 6000 ppm, Cl < 20 ppm, asphaltenes < 8%, gums < 25%, and metals < 20 ppm; distilling the pretreated coal tar to separate a first fraction at 130-360℃; subjecting the first fraction to a hydrorefining reaction; separating a second fraction at 130-320℃ from the first fraction after the hydrorefining reaction; subjecting the second fraction to a hydromodification reaction; and separating the second fraction after the hydromodification reaction to obtain jet fuel blank oil. The method employs multi-point control and multi-point adjustment to ensure that the various product properties of the jet fuel meet the corresponding technical requirements, and the blending components in the rectification section increase the flexibility of adjusting the various product properties of the jet fuel.

Description

Technical Field

[0001] This application relates to the field of coal chemical technology, specifically to a jet fuel and its preparation method. Background Technology

[0002] Traditional No. 3 jet fuel is refined from petroleum, and its feedstock fraction accounts for only 4%-8% of the total crude oil. The density, calorific value, and other properties of petroleum-based jet fuel have reached their limits, and its production and supply are constrained by the global market and international situation. Petroleum-based aviation kerosene can no longer meet the requirements of future supersonic aircraft, while coal-based specialty fuels have significant advantages and development potential in terms of density, freezing point, and thermal stability, making them a viable alternative to petroleum-based aviation kerosene. Currently, the main technological routes for replacing petroleum with coal-based aviation kerosene include direct coal liquefaction, indirect coal liquefaction, and coal tar hydrogenation.

[0003] Coal indirect liquefaction-Fischer-Tropsch synthesis for jet fuel: Coal indirect liquefaction is the process of converting carbon-based feedstocks into jet fuel, which mainly involves three steps: coal powder is converted into syngas; syngas is converted into crude oil; and crude oil is reformed to produce aviation fuel.

[0004] Currently, coal-based aviation fuel has been successfully produced worldwide using Fischer-Tropsch oil, primarily through two methods: semi-synthetic and fully synthetic aviation fuel. Semi-synthetic aviation fuel technology is relatively mature and has been commercially applied. Fully synthetic aviation fuel, which does not use petroleum-based fuels for blending, has not yet been formally commercialized; however, it underwent its first passenger flight trial in September 2010.

[0005] Fischer-Tropsch fuel, currently the most researched coal-based fuel, boasts numerous advantages, including ultra-low sulfur, low aromatics, and low ash content. Many of its properties meet or even exceed fuel standards. However, some properties still deviate from these standards, preventing its direct use. Its main drawbacks are as follows: ① Low aromatic content in low-temperature Fischer-Tropsch oil, failing to meet the minimum density requirements for jet fuel; ② Low lubricity, failing to meet lubrication requirements; ③ Poor sealing performance, failing to meet sealing requirements; ④ High freezing point, failing to meet requirements; ⑤ Complex preparation process.

[0006] Coal direct liquefaction oil for jet fuel preparation: Coal direct liquefaction oil is an excellent feedstock for coal-based jet fuel. Shenhua Group has made breakthrough progress in its research on coal-based jet fuel. The resulting coal-based jet fuel has advantages such as low sulfur and nitrogen content, high specific gravity, high heat capacity, high thermal stability, and high volumetric calorific value. Many indicators are superior to petroleum-based aviation fuels, basically meeting the standards for No. 3 jet fuel. However, its acid value and net calorific value do not meet the standards, requiring further upgrading and modification of the oil.

[0007] Coal tar hydrogenation to prepare jet fuel: Coal tar is a liquid product obtained during coal dry distillation. The tar obtained by high-temperature dry distillation (1000℃) is called high-temperature coal tar, and the tar obtained by medium- and low-temperature dry distillation (600-900℃) is called medium- and low-temperature coal tar.

[0008] High-temperature coal tar has a high content of polycyclic aromatic hydrocarbons, which can be further separated into various chemicals, while medium- and low-temperature coal tar is more suitable for fuel production. However, because medium- and low-temperature coal tar contains a large number of heteroatoms such as nitrogen, sulfur, and oxygen, it not only damages engines but also emits large amounts of nitrogen oxides and sulfur oxides, polluting the environment. Therefore, it is necessary to hydrogenate and upgrade coal tar to remove nitrogen, sulfur, oxygen, and other heteroatoms and increase the H / C ratio in order to produce fuels such as gasoline, kerosene, and diesel.

[0009] Currently, Applied Research Pennsylvania in the United States has successfully produced JP-900, a fuel suitable for use in aviation. JP-900 is a viable alternative to coal-based jet fuel, offering high thrust and good heat dissipation. However, JP-900 has low hydrogen content, low heat of combustion, and low API gravity. Coal-based jet fuels, on the other hand, have high density and low heat of combustion, aligning with the development trend of jet fuels. JP-10 and RJ-5, primarily chemically synthesized oils, are more expensive, thus highlighting the promising application prospects of coal-based jet fuels. Summary of the Invention

[0010] The purpose of this application is to provide a process for preparing jet fuel using medium- and low-temperature coal tar. Based on the molecular composition of coal tar, which is rich in aromatics and straight-chain alkanes, this application utilizes coal tar pretreatment technology and fixed-bed hydrogenation of coal tar to prepare a coal-based jet fuel product that overcomes the limitations of petroleum-based jet fuels in terms of density, calorific value, and other properties. Addressing the constraints of the global market and international situation on the production and supply of petroleum-based jet fuels, this application provides a methodological route with significant advantages and development potential as a substitute for petroleum-based aviation kerosene.

[0011] According to one aspect of this application, a method for preparing jet fuel is provided, comprising: using medium- and low-temperature coal tar as raw material, subjecting it to one or more pretreatments including delayed coking, hydrorefining, hydrocracking, fluidized bed, slurry bed, and fractionation, wherein the pretreated coal tar contains S < 1000 ppm, N < 6000 ppm, Cl < 20 ppm, asphaltenes < 8%, gums < 25%, and metals < 20 ppm. The pretreated medium- and low-temperature coal tar is then subjected to a series of treatments: primary distillation, hydrorefining, secondary distillation, hydromodification, and tertiary distillation, to obtain jet fuel blank oil.

[0012] According to some embodiments of this application, the pretreated coal tar is distilled to separate a first fraction at 130-360°C;

[0013] The first fraction is subjected to a hydrogenation purification reaction;

[0014] A second fraction at 130-320℃ is separated from the first fraction after hydrorefining.

[0015] The second fraction was subjected to a hydrogenation reforming reaction;

[0016] The fraction with a temperature of 150-240℃ is separated from the second fraction after hydrotreating and used as jet fuel blank oil; the light component with a temperature of <140℃ and the heavy component with a temperature of >240℃ are used as jet fuel blank oil blending components to adjust the flash point, density, distillation range and other properties of the jet fuel blank oil.

[0017] Alternatively, a fraction with a temperature of 140-280℃ can be separated from the second fraction after hydrotreating to serve as jet fuel blank oil; the light component with a temperature <140℃ and the heavy component with a temperature >280℃ can be used as blending components for jet fuel blank oil to adjust the flash point, density, distillation range and other properties of the jet fuel blank oil.

[0018] Alternatively, a fraction with a temperature of 190-280℃ can be separated from the second fraction after hydrotreating to serve as jet fuel blank oil; the light component with a temperature <190℃ and the heavy component with a temperature >280℃ can be used as blending components for jet fuel blank oil to adjust the flash point, density, distillation range and other properties of the jet fuel blank oil.

[0019] According to some embodiments of this application, the hydrorefining reaction includes: a primary refining reaction and a secondary refining reaction; the primary refining reaction and the secondary refining reaction are carried out in a primary refining reactor and a secondary refining reactor, respectively;

[0020] The primary refining reactor is filled with refining catalysts used in the hydrogenation of coal tar to naphtha and diesel, thereby reducing the input cost of the catalysts.

[0021] The secondary refining reactor is filled with jet fuel refining agent. The main active components of the jet fuel refining agent include WoO ≥ 14 wt%, MO3 ≥ 6.0 wt%, and NiO ≥ 3.5 wt%.

[0022] According to some embodiments of this application, the primary refining reactor and the secondary refining reactor can be combined into a single primary reactor, both of which are filled with jet fuel refining agent.

[0023] According to some embodiments of this application, the reaction temperature of the hydrorefining reactor is 320-420°C, the pressure is 13-16 MPa, and the space velocity is 0.25-0.8 h⁻¹. -1The hydrogen-to-oil ratio is (800-1500):1; and after the first-stage hydrorefining reaction is completed, the first fraction contains S≤10 ppm and N≤100 ppm, and after the second-stage hydrorefining reaction is completed, the first fraction contains S≤2 ppm and N≤2 ppm.

[0024] Optionally, the reaction temperature of the primary refining reactor is 360-400℃, the pressure is 13.5-16.0 MPa, and the space velocity is 0.35-0.8 h⁻¹. -1 The hydrogen-to-oil ratio is (1200-1500):1.

[0025] According to some embodiments of this application, the hydrotreating reaction includes: hydroisomerization reaction and supplementary refining reaction; the hydrotreating reaction can improve the low-temperature flow and thermal stability of distillate oils.

[0026] According to some embodiments of this application, the hydroisomerization reaction and the supplementary purification reaction are carried out in hydroisomerization reactors and supplementary purification reactors, respectively; the hydroisomerization reactor is filled with an isomerization catalyst, the main components of which include: 0.25-0.40 wt% platinum series noble metals, the remainder being alumina and molecular sieves; the supplementary purification reactor is filled with a nickel-based supplementary purification catalyst, the main components of which include: 25-40 wt% NiO and 5-8 wt% additives.

[0027] A platinum-based precious metal hydroisomerization catalyst is packed into a hydroisomerization reactor to improve the low-temperature flowability of oil products. The reactor operates at a reaction temperature of 300-380℃, a pressure of 2-6 MPa, a hydrogen-to-oil ratio of (400-1000):1, and a space velocity of 0.35-1.2 h⁻¹. -1 .

[0028] According to some embodiments of this application, the nickel-based supplemental refining catalyst in the supplemental refining reactor of this application carries out an aromatic saturation reaction to adjust the hydrocarbon composition of the oil. The reaction temperature of the supplemental refining reactor is 130-300℃, the pressure is 2-6MPa, the hydrogen-to-oil ratio is (400-1000):1, and the space velocity is 0.35-1.2h. -1 .

[0029] According to some embodiments of this application, the preparation method of this application further includes coalescing adsorption and ultra-fine filtration of the jet fuel blank oil to remove dust, catalyst powder and moisture generated in jet fuel production or other processes.

[0030] Compared with the prior art, this application has at least the following beneficial effects:

[0031] This application provides a method for preparing coal-based jet fuel from coal tar. It utilizes coal tar hydrogenation technology, distillation, and ultrafiltration to develop a combined method for preparing coal-based jet fuel through two-stage hydrogenation, multi-stage distillation, and multi-stage purification of coal tar via hydrogenation, distillation, and purification.

[0032] The method described in this application employs a three-stage distillation process, separating the hydrogenation feedstock fraction, hydrogenation middle fraction, and jet fuel blank oil distillate for jet fuel production. This multi-point control and adjustment ensures that the final jet fuel meets the relevant technical requirements for all product properties. The blending components produced in the rectification stage increase the flexibility for adjusting the various product properties of the jet fuel.

[0033] The preparation process of this application is designed with two-stage hydrogenation and three-stage hydrogenation refining. Utilizing mature fixed-bed hydrogenation technology, the two-stage multi-stage hydrogenation method can deeply remove impurities such as sulfur, nitrogen, oxygen, metals, and asphaltenes. It can flexibly adjust the hydrocarbon composition of the oil and improve the oil's low-temperature fluidity and thermal stability.

[0034] This application designs a two-stage purification system, employing mature adsorption and ultra-fine filtration technologies to remove dust, catalyst powder, moisture, and other factors that affect the cleanliness and conductivity of jet fuel generated during jet fuel production or other processes. Attached Figure Description

[0035] Figure 1 This application presents a flowchart of a coal-to-jet fuel preparation method according to an example embodiment. Detailed Implementation

[0036] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] It should be particularly noted that similar substitutions and modifications made to this application are obvious to those skilled in the art, and they are all considered to be included in this application. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0038] Unless otherwise specified, this application is conducted under standard conditions or conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, whose manufacturers are not specified, are all conventional products that can be obtained commercially.

[0039] The following is a detailed description of this application.

[0040] This application utilizes existing mature coal tar hydrogenation methods to provide a method for preparing coal-based jet fuel. Taking advantage of the rich aromatic and straight-chain alkane composition of coal tar, a coal-based jet fuel product is prepared that overcomes the limitations of petroleum-based jet fuels in terms of density, calorific value, and other properties. Addressing the constraints of the global market and international situation on the production and supply of petroleum-based jet fuels, this application provides a methodological and technical route with significant advantages and development potential as a substitute for petroleum-based aviation kerosene.

[0041] This application relies on fixed-bed coal tar hydrogenation technology, which features a simple technical route, stable equipment performance, and low operation and maintenance costs. It is highly feasible and can be implemented independently or by upgrading existing industrial coal tar hydrogenation plants for gasoline and diesel production, or by constructing side-stream units to produce coal-to-jet fuels.

[0042] This application employs a three-stage distillation and two-stage filtration technology, utilizing multi-point control and multi-point adjustment to ensure the final jet fuel product properties from the hydrogenated feedstock fraction and hydrogenated intermediate fraction to the jet fuel blank oil distillate.

[0043] This application employs a two-stage hydrogenation and a three-stage hydrogenation refining multi-stage hydrogenation method, which can deeply remove impurities such as sulfur and nitrogen, flexibly adjust the hydrocarbon composition of oil products, break through the limits of properties such as density and calorific value of petroleum-based jet fuels, and overcome the performance defects of coal indirect liquefaction-Fischer-Tropsch synthesis technology and coal direct liquefaction oil preparation of jet fuels.

[0044] This application utilizes pretreated coal tar fractions, combined with multi-stage hydrorefining, multi-stage distillation and multi-stage purification technologies, to form a combined method for preparing coal-based jet fuel by coal tar hydrorefining and purification, including: raw material pretreatment (11), multi-stage distillation (21, 22, 23), two-stage hydrorefining (30-34, 35-39), multi-stage purification (41, 42) and additive system (51).

[0045] Raw material selection (01): This application selects medium- and low-temperature coal tar as the raw material for the production of coal-based jet fuel. Its production method should be a liquid product obtained by dry distillation / pyrolysis of coal at 500-900℃.

[0046] Pretreatment (11): refers to the treatment method of medium and low temperature coal tar. One, two or more treatment methods such as delayed coking, hydrorefining, hydrocracking, fluidized bed, suspension bed, and fraction cutting are adopted.

[0047] First-stage distillation (21): Separating fractions from the pretreated coal tar fraction at 130-360℃ as feedstock for subsequent units. The main purpose of first-stage distillation is to precisely control the distillation range of the hydrogenation feedstock fraction for jet fuel preparation, ensuring that it meets the hydrocarbon composition requirements of jet fuel, such as alkanes, cycloalkanes, and aromatics, while also retaining a certain degree of operational flexibility (to extract suitable fractions for jet fuel preparation from the coal tar fraction as much as possible, while controlling the quality of the jet fuel preparation fraction from the source).

[0048] Hydrogenation refining reaction (30-34): Heating furnace (30) -- First stage hydrogenation protection reactor (31) -- First stage hydrogenation refining (32) -- Second stage hydrogenation refining (33) -- Separation system (34).

[0049] The hydrorefining reaction employs a two-stage hydrorefining process. Under the action of a catalyst and hydrogen, the non-hydrocarbon components and organometallic compounds in the hydrorefined feedstock undergo hydrogenolysis. The 130-360℃ fraction produced by distillation is subjected to two stages of deep refining through primary and secondary refining. The primary hydrorefining reactor effectively removes metallic impurities and solid particles from the feedstock and moderately hydrogenates easily coking substances to mitigate catalyst poisoning and coking, extending the lifespan of the main catalyst. The primary hydrorefining reactor mainly removes sulfur, nitrogen, oxygen, metallic impurities, and asphaltenes. The secondary hydrorefining reactor performs further deep hydrorefining, removing sulfur, nitrogen, and other heteroatoms. Through this two-stage hydrorefining process, sulfur and nitrogen levels are controlled below 2 ppm.

[0050] Optionally, the hydrorefining process includes a first protective agent in the hydrorefining protection reactor; the active components of the first protective agent are MO3 ≥ 7.0 wt% and NiO ≥ 1.5 wt%. This agent can remove metal elements from the feed, and remove impurities such as sulfur, nitrogen, and oxygen from non-hydrocarbon compounds in the feed, converting them into H2S, NH3, and H2O. This improves the quality of the hydrorefining feed, inhibits the blockage of the main catalyst pores and the covering of active centers by impurities, protects the activity and stability of the main catalyst, and extends its service life.

[0051] The separation system removes acidic gases containing NH3 and H2S, as well as sulfur-containing wastewater, generated during the first hydrogenation refining reaction.

[0052] Secondary distillation (22): A fraction of 130-320℃ is extracted from the product oil fraction of the first hydrorefining reaction and used as feed for the subsequent second hydrorefining reaction. The main purpose of secondary distillation is to precisely control the distillation range of the hydrorefined intermediate distillate oil for preparing jet fuel, remove other fractions, and reduce the load on the second hydrorefining unit.

[0053] Hydrogenation reforming reaction (35-39): two-stage hydrogenation heating furnace (35) -- two-stage hydrogenation protection reactor (36) -- hydrogenation isomerization reactor (37) -- supplementary purification reactor (38) -- separation system (34).

[0054] In hydrorefining, the middle distillate undergoes reactions including isomerization and saturation under the influence of a catalyst and hydrogen, altering the alkane molecular structure and hydrocarbon composition. Hydrorefining reactions are conducted with hydroisomerization and supplementary hydrorefining, primarily to perform isomerization and aromatic saturation reactions on the 130-320℃ fraction produced by the hydrorefining reaction, thereby improving the oil's low-temperature flow and thermal stability.

[0055] The two-stage hydrotreating reactor, used for deep desulfurization and nitrogen removal, protects the precious metal isomerization catalyst. The hydroisomerization reactor primarily aims to improve the low-temperature flow of the oil. The supplementary refining reactor mainly aims to alter the hydrocarbon composition of the oil and improve its thermal stability.

[0056] Optionally, the two-stage hydrogenation protection reactor is filled with a second protective agent, which includes a refining protective agent and a desulfurization protective agent. Deep desulfurization of nitrogen protects the noble metal isomeric catalyst. The refining protective agent mainly comprises: 20-35 wt% active metal WoO / MO3 / NiO, 2-7 wt% additives, and the remainder Al2O3. The active component of the desulfurization protective agent includes zinc oxide, wherein the zinc oxide content is ≥90%.

[0057] Further optionally, the reaction temperature of the two-stage hydrogenation protection reactor is 300-360℃, the reaction pressure is 2-6 MPa, the hydrogen-to-oil ratio is (400-1000):1, and the space velocity is 0.35-1.2 h⁻¹. -1 .

[0058] The separation system removes acidic gases containing NH3 and H2S, as well as sulfur-containing wastewater, generated during the second hydrogenation refining reaction.

[0059] Three-stage distillation (23): preparation of jet fuel blank oil and jet fuel blank oil blending components.

[0060] The main purpose of three-stage distillation is to precisely control the distillation range of the jet fuel blank oil, while removing other light fractions and heavy fractions to adjust the flash point, density, distillation range, and other properties of the jet fuel blank oil.

[0061] Purification (41, 42): The blank fuel oil for jet fuel undergoes coalescing adsorption and ultra-fine filtration in sequence to remove dust, catalytic powder, moisture and other factors that affect the cleanliness, conductivity and other properties of jet fuel generated in jet fuel production or other processes, so as to ensure product quality.

[0062] Additives system (51): Jet fuel blank oil can be sold as a product. An additives system is set up to add specific types of additives according to market demand, for example, to prepare special-purpose No. 3 jet fuel products.

[0063] The additive system (51) and purification system (41, 42) are combined to ensure that the product meets the technical requirements of specific markets and guarantees the quality of jet fuel products.

[0064] Example

[0065] according to Figure 1 The process prepares No. 3 jet fuel product.

[0066] (1) Medium and low temperature coal tar was used as the raw material for the production of coal-based No. 3 jet fuel. After delayed coking pretreatment, it was fed into the distillation unit to cut the first fraction at 130-360℃ and its index parameters were tested as shown in Table 1.

[0067] Table 1. Specifications of Hydrogenation Feedstock

[0068] project index <![CDATA[Density (20 °C), g / cm 3 > 0.924 IBP / 10% 126 / 215 30％ / 50％ 262 / 291 70％ / 90％ 338 / 354 Moisture% 0.12 S, PPm 960.0 N, PPm 5875.0

[0069] (2) After the first fraction is heated in a heater, it sequentially passes through a first-stage hydrotreating reactor, a first-stage hydrorefining reactor, and a second-stage hydrorefining reactor to obtain the hydrorefined product oil. Process conditions are shown in Table 2.

[0070] Table 2 Hydrorefining Reaction Process Conditions

[0071]

[0072] (3) The oil produced by the first hydrorefining reaction is separated by a separation device to remove acidic gases containing NH3 and H2S and sulfur-containing wastewater, and hydrotreated middle distillate oil is obtained; the hydrotreated middle distillate oil enters the secondary distillation unit to extract the second fraction at 130-320℃.

[0073] (4) After being heated in a furnace, the second fraction passes sequentially through a two-stage hydrotreating protection reactor, a hydroisomerization reactor, and a supplementary refining reactor. The outflowing production oil enters a separation unit to separate acidic gases and sulfur-containing wastewater, yielding the hydrotreated oil. Process conditions are shown in Table 3.

[0074] Table 3 Hydrogenation Reforming Reaction Process Conditions

[0075]

[0076] (5) The oil produced by the hydrorefining reaction enters the three-stage distillation unit, and the 150-240℃ fraction is used as the No. 3 jet fuel blank oil. The <150℃ fraction and the >240℃ fraction are used as blending components to adjust the flash point and density of the jet fuel product, so as to obtain the jet fuel blank oil that meets the technical requirements of GB 6537-2018.

[0077] The jet fuel base oil passes through a purification system and an additive system in sequence to obtain No. 3 jet fuel product that meets certain user requirements.

[0078] The properties of the No. 3 jet fuel oil prepared in this embodiment were tested, and the results are shown in Table 4:

[0079] Table 4. Properties of No. 3 Jet Fuel Oil

[0080]

[0081]

[0082] Comparative Example 1 only underwent the first hydrorefining reaction (hydrogenated middle distillate oil).

[0083] The jet fuel oil was processed using the same preparation process as in the examples, except that only the first hydrorefining reaction was performed to obtain a hydrotreated middle distillate oil with a temperature range of 130-360°C. The properties of the jet fuel oil prepared in this comparative example were tested, and the results are shown in Table 5. It can be seen that the main properties of its hydrotreated middle distillate oil, such as density, hydrocarbon composition, and freezing point, do not meet the technical requirements of GB6537-2018 and cannot be used as a jet fuel product.

[0084] Table 5 Main Properties of Products

[0085] Testing items unit GB6537 Middle distillate oil Detection methods Aromatic content ％(V) No greater than 20.0 41 SH / T 0606 Flash point (closed cup) ℃ No less than 38 36 GB / T 21789 Density (20℃) <![CDATA[kg / m 3 ]]> 775-830 866.1 GB / T 1884 freezing point ℃ Not higher than -47 -25 SH / T 0770

[0086] Comparative Example 2 underwent two distillations.

[0087] The jet fuel oil was processed using the same preparation process as in the example, except that only two distillations were performed.

[0088] This comparative example confirms that coal tar hydrogenation is a process of lightening the oil. Under the action of hydrogen and catalyst, the oil produced by the first hydrorefining reaction at 130-320℃ undergoes isomerization and aromatic saturation reactions to obtain the oil produced by the second hydrorefining reaction with a final boiling point ≤320℃ and an initial boiling point <130℃. If this oil is used directly as No. 3 jet fuel, it may have a flash point (closed cup) that does not meet the requirement of not being lower than 38℃ and a density (20℃) that does not meet the requirement of 775-830 kg / m³. 3 A series of issues, such as the freezing point not exceeding -47℃, require fractional distillation to determine the flash point, density, distillation range, and other properties of the No. 3 jet fuel blank oil.

[0089] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method for preparing jet fuel, characterized in that, include: The medium- and low-temperature coal tar is pretreated, wherein the pretreatment includes one or more of delayed coking, hydrorefining, hydrocracking, and fraction cutting. The pretreated coal tar contains S < 1000 ppm, N < 6000 ppm, Cl < 20 ppm, asphaltenes < 8%, gums < 25%, and metals < 20 ppm. The pretreated coal tar was distilled to separate the first fraction at 130-360℃; The first fraction is subjected to a hydrogenation purification reaction; A second fraction at 130-320℃ is separated from the first fraction after hydrorefining. The second fraction was subjected to a hydrogenation reforming reaction; The second fraction after hydrotreating is separated to obtain jet fuel blank oil; The hydrogenation refining reaction includes a primary refining reaction and a secondary refining reaction; The primary purification reaction and the secondary purification reaction are carried out in a primary purification reactor and a secondary purification reactor, respectively. The primary refining reactor is filled with a refining catalyst; the secondary refining reactor is filled with jet fuel refining agent; Alternatively, both the primary refining reactor and the secondary refining reactor may be filled with jet fuel refining agent.

2. The preparation method according to claim 1, characterized in that, The hydrogenation reaction includes: hydroisomerization reaction and supplementary purification reaction; The hydroisomerization reaction and the supplementary purification reaction are carried out in the hydroisomerization reactor and the supplementary purification reactor, respectively. The hydrogen isomerization reactor is filled with an isomerization catalyst, which comprises: platinum series noble metals, alumina and molecular sieves. The supplementary refining reactor is filled with a supplementary refining agent, which comprises NiO and additives.

3. The preparation method according to claim 2, characterized in that, The isomeric catalyst has the following composition by mass percentage: 0.2-0.4% platinum series precious metals, with alumina and molecular sieve as the remainder; The supplementary refining agent has the following composition by mass percentage: NiO 25-40%, and auxiliaries 5-8%.

4. The preparation method according to claim 2, characterized in that, The hydrorefining reaction is carried out at a temperature of 320-420℃, a pressure of 13-16 MPa, and a space velocity of 0.25-0.80 h⁻¹. -1 The hydrogen-to-oil ratio is (800-1500):1; After the first-stage purification reaction is completed, the first fraction contains S ≤ 10 ppm and N ≤ 100 ppm. After the second-stage purification reaction is completed, the first fraction contains S ≤ 2 ppm and N ≤ 2 ppm.

5. The preparation method according to claim 3, characterized in that, The reaction temperature in the hydroisomerization reactor is 300-380℃, the pressure is 2.0-6.0 MPa, the hydrogen-to-oil ratio is (400-1000):1, and the space velocity is 0.35-1.2 h⁻¹. -1 ; The reaction temperature in the supplementary refining reactor is 130-300℃, the pressure is 2.0-6.0 MPa, the hydrogen-to-oil ratio is (400-1000):1, and the space velocity is 0.35-1.2 h⁻¹. -1 .

6. The preparation method according to claim 1, characterized in that, Also includes: The jet fuel blank oil is subjected to coalescing adsorption and ultra-fine filtration in sequence.

7. A jet fuel prepared by any one of claims 1-6.

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