Coal-based jet fuel and method of making

Abstract

The present application provides a coal-based jet fuel and a preparation method thereof. The coal-based jet fuel comprises a mixed fraction and an additive, the mixed fraction comprising a coal direct liquefaction kerosene fraction and a coal indirect liquefaction kerosene fraction, the coal direct liquefaction kerosene fraction having a distillation range of 120-300 DEG C, and the coal indirect liquefaction kerosene fraction having a distillation range of 160-280 DEG C. The present application utilizes the characteristics of the coal direct liquefaction kerosene fraction with a specific distillation range and the coal indirect liquefaction kerosene fraction with a specific distillation range, and uses the additive to synergize with them, to obtain a coal-based jet fuel. The coal direct liquefaction kerosene fraction and the coal indirect liquefaction kerosene fraction are widely available and easy to obtain. The coal-based jet fuel has low preparation cost and high performance, meets the index requirements of jet fuel, and moreover, requires less devices and equipment, has low investment cost, can greatly reduce production cost, and has high market competitiveness.

Description

Technical Field

[0001] This invention relates to the field of coal chemical industry, and more specifically, to a coal-based jet fuel and its preparation method. Background Technology

[0002] In the petroleum refining process, straight-run aviation kerosene fraction accounts for only 4-8% of the total crude oil volume, and even after hydrocracking, it only accounts for about 20%. With the rapid development of my country's aviation market, the demand for aviation kerosene is gradually increasing, and the shortage is becoming increasingly apparent. Therefore, it is necessary to synthesize liquid fuels through non-petroleum routes to solve the supply and demand problem of aviation kerosene.

[0003] The technology for producing coal-based aviation kerosene can be divided into two categories: direct coal liquefaction and indirect coal liquefaction. Direct coal liquefaction, also known as coal hydrogenation liquefaction, is a coal utilization method that utilizes coal to produce small-molecule oil products through the pyrolysis and liquefaction of coal macromolecules under high temperature, high pressure, and hydrogen-containing conditions with the aid of solvents and catalysts. In the direct liquefaction reactor, pulverized coal mainly undergoes macromolecular breakage and free radical hydrogenation reactions. Indirect coal liquefaction, also known as the Fischer-Tropsch synthesis reaction, involves first gasifying coal with oxygen and steam to produce syngas (a mixture of H2 and CO). The syngas then reacts under the action of a catalyst to produce liquid hydrocarbons, waxes, gaseous light hydrocarbons, and some organic oxygen-containing compounds. The intermediate products can be processed to obtain diesel, gasoline, kerosene, naphtha, liquefied petroleum gas (LPG), and fine chemicals. Indirect coal liquefaction has become one of the preferred technological routes for developing my country's coal-to-oil industry.

[0004] Invention patent CN101928599A discloses a method for producing jet fuel or jet fuel blends, in which Fischer-Tropsch synthetic oil is mixed with direct coal liquefaction oil to obtain a blended oil, which is then hydrorefined, hydroisomerized, and fractionated to obtain jet fuel or jet fuel blends. However, this technical route does not fully utilize the characteristics of existing technology products, and the process route requires additional equipment, further increasing investment costs. Summary of the Invention

[0005] The main objective of this invention is to provide a coal-based jet fuel and its preparation method, in order to solve the problems that the product characteristics of direct coal liquefaction kerosene fraction and indirect coal liquefaction kerosene fraction are not fully utilized in the prior art, as well as the large number of equipment and high investment costs required for the process route.

[0006] To achieve the above objectives, according to one aspect of the present invention, a coal-based jet fuel is provided, comprising a mixed fraction and an additive, wherein the mixed fraction includes a direct coal liquefaction kerosene fraction and an indirect coal liquefaction kerosene fraction, wherein the direct coal liquefaction kerosene fraction has a boiling range of 120–300°C and the indirect coal liquefaction kerosene fraction has a boiling range of 160–280°C.

[0007] Further, the initial boiling point of the coal-to-kerosene fraction is 120–160°C, and the final boiling point is 280–300°C; preferably, the boiling range of the coal-to-kerosene fraction is 150–290°C; more preferably, the initial boiling point of the coal-to-kerosene fraction is 150–160°C, and the final boiling point is 280–290°C; and / or the initial boiling point of the coal-to-kerosene fraction is 160–175°C, and the final boiling point is 260–280°C; preferably, the boiling range of the coal-to-kerosene fraction is 170–270°C; more preferably, the initial boiling point of the coal-to-kerosene fraction is 170–175°C, and the final boiling point is 260–270°C.

[0008] Further, the mass ratio of direct coal liquefaction kerosene fraction to indirect coal liquefaction kerosene fraction is (15:85) to (85:15); preferably (40:60) to (60:40). Further, the additives include antistatic agents and / or anti-wear agents; preferably, the antistatic agent is one or more of Stadis450, T1501, and T1502; and / or the solid-liquid ratio of the antistatic agent to the mixed fraction is 0.5 to 3.0 mg / L, more preferably 1 to 2 mg / L; preferably, the anti-wear agent is one or more of T1602, T1601, T305, and T306; and / or the solid-liquid ratio of the anti-wear agent to the mixed fraction is 2 to 25 mg / L, more preferably 10 to 20 mg / L.

[0009] According to another aspect of the present invention, a method for preparing coal-based jet fuel is provided, wherein a direct coal liquefaction kerosene fraction, an indirect coal liquefaction kerosene fraction, and additives are mixed to obtain coal-based jet fuel.

[0010] Further, the mixing method is either tank mixing or pipeline mixing. Preferably, tank mixing is one or more of compressed air mixing, mechanical stirring mixing, and pump circulation mixing. More preferably, when the mixing method is compressed air mixing, the air source pressure is 0.3–0.6 MPa, the pulse frequency is 5–20 times / minute, and the injection time is 0.5–2 seconds / injection. And / or when the mixing method is mechanical stirring mixing, the stirring speed is 300–500 rpm, and the stirring time is 20–50 minutes. And / or when the mixing method is pump circulation mixing, the pump flow rate is 20–50 m³ / min. 3 / h.

[0011] Further, the coal direct liquefaction kerosene fraction is prepared through the following steps: Step S11, the crude coal direct liquefaction oil is subjected to a hydrogenation stabilization reaction to obtain the first intermediate product of coal direct liquefaction; Step S12, the first intermediate product of coal direct liquefaction is subjected to a first fractionation to obtain the second intermediate product of coal direct liquefaction, the distillation range of the second intermediate product of coal direct liquefaction being 120-300℃; Step S13, the second intermediate product of coal direct liquefaction is subjected to a first hydrogenation refining reaction and a first hydrogenation cracking reaction in sequence to obtain the third intermediate product of coal direct liquefaction; Step S14, the third intermediate product of coal direct liquefaction is subjected to a second fractionation to obtain the coal direct liquefaction kerosene fraction.

[0012] Further, in step S11, the reaction temperature of the hydrogenation stabilization reaction is 360–390°C, preferably 360–375°C; and / or the reaction pressure is 11–14 MPa, preferably 12–14 MPa; and / or the volume hourly space velocity is 0.5–2 h⁻¹. -1 Preferably, it is 0.8 to 1.2 hours. -1 The hydrogen-to-oil ratio is 300–700, preferably 400–600; in step S12, the reaction pressure of the first fractionation is 0.4–0.6 MPa; in step S13, the reaction temperature of the first hydrorefining reaction is 300–400 °C, preferably 330–370 °C; and / or the reaction pressure is 8–15 MPa, preferably 10–12 MPa; and / or the volume hourly space velocity is 0.5–3 h⁻¹. -1 Preferably 0.5 to 1 hour -1 The hydrogen-to-oil ratio is 200–600, preferably 200–500; in step S13, the reaction temperature of the first hydrocracking reaction is 310–400°C, preferably 330–380°C; the reaction pressure is 6–14 MPa, preferably 11–13 MPa; and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 Preferably 1 to 1.5 hours -1 The hydrogen-to-oil ratio is 200–800, preferably 400–600; in step S14, the second fractionation is carried out in the first fractionation column, the bottom temperature of the first fractionation column is 300–360°C, preferably 310–340°C; and / or the top temperature is 100–160°C, preferably 110–140°C; and / or the bottom pressure is 0.1–1.1 MPa, preferably 0.2–0.6 MPa.

[0013] Further, the coal indirect liquefaction kerosene fraction is prepared through the following steps: Step S21, the crude Fischer-Tropsch synthesis oil is subjected to a second hydrorefining reaction to obtain the first intermediate product of coal indirect liquefaction; Step S22, the first intermediate product of coal indirect liquefaction is subjected to a third fractionation to obtain the second intermediate product of coal indirect liquefaction, the distillation range of the second intermediate product of coal indirect liquefaction being 160–310℃; Step S23, the second intermediate product of coal indirect liquefaction is subjected to a second hydrocracking reaction to obtain the third intermediate product of coal indirect liquefaction; Step S24, the third intermediate product of coal indirect liquefaction is subjected to a fourth fractionation to obtain the coal indirect liquefaction kerosene fraction.

[0014] Further, in step S21, the reaction temperature of the second hydrogenation refining reaction is 270–360°C, preferably 290–330°C; and / or the reaction pressure is 2–8 MPa, preferably 2–6 MPa; and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 Preferably 0.5 to 2 hours -1 The hydrogen-to-oil ratio is 200–700, preferably 250–500; in step S22, the number of trays in the third fractionation is 50–70; and / or the reflux ratio is (3–5):1; and / or the operating pressure is 0.5–1.5 MPa; and / or the bottom temperature is 300–350 °C; in step S23, the reaction temperature of the second hydrocracking reaction is 300–380 °C, preferably 300–350 °C; and / or the reaction pressure is 2–10 MPa, preferably 3–6 MPa; and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 Preferably, it is 0.5 to 1.5 hours. -1 The hydrogen-to-oil ratio is 200–800, preferably 300–600; in step S24, the fourth fractionation is carried out in the second fractionation column, which has 50–70 trays; the reflux ratio is (3–5):1; the bottom temperature is 290–370°C, preferably 290–330°C; the top temperature is 100–150°C, preferably 100–130°C; and the bottom pressure is 0.1–1.1 MPa, preferably 0.15–0.5 MPa.

[0015] By applying the technical solution of this invention, utilizing the characteristics of coal direct liquefaction kerosene fractions and coal indirect liquefaction kerosene fractions with specific distillation ranges, and using additives in synergistic effects, a coal-based jet fuel is obtained. Coal direct liquefaction kerosene fractions and coal indirect liquefaction kerosene fractions are widely available and easily obtained. The addition of additives can improve the safety and friction-reducing performance of the coal-based jet fuel. The resulting coal-based jet fuel has low preparation cost, high performance, and meets jet fuel performance requirements. Moreover, the coal direct liquefaction kerosene fractions and coal indirect liquefaction kerosene fractions in the coal-based jet fuel components can be prepared using existing production processes, without the need for additional equipment outside of existing production lines. This coal-based jet fuel requires less equipment, has low investment costs, can significantly reduce production costs, and has high market competitiveness. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A schematic diagram of the coal-based jet fuel preparation process according to Embodiment 1 of the present invention is shown.

[0018] The above figures include the following reference numerals:

[0019] 1. Coal direct liquefaction reactor; 2. Hydrogenation stabilization reactor; 3. First intermediate fractionation column; 4. First hydrorefining reactor; 5. First hydrocracking reactor; 6. First fractionation column; 7. Fischer-Tropsch synthesis reactor; 8. Second intermediate fractionation column; 9. Second hydrorefining reactor; 10. Third intermediate fractionation column; 11. Second hydrocracking reactor; 12. Second fractionation column; 13. Mixer;

[0020] 14. Feedstock for direct coal liquefaction; 15. Feedstock for indirect coal liquefaction; 16. Top and side stream products; 17. Additives; 18. Coal-based jet fuel. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the terms "first," "second," etc., in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate to describe embodiments of the invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] Terminology Explanation:

[0024] Solid-liquid ratio: The mass of solid (mg) corresponding to a unit volume (L) of liquid.

[0025] Hydrogenation stabilization: Crude oil from a direct coal liquefaction unit is processed under certain temperature, pressure, catalyst, and hydrogen conditions to produce a hydrogen-supplying solvent that meets the requirements of coal liquefaction. At the same time, hydrorefining feedstock is produced and impurities such as sulfur, nitrogen, oxygen, and metals are removed, thereby pre-refining the crude oil.

[0026] Hydrorefining: Under certain temperature, pressure, catalyst and hydrogen conditions, feedstock oil and hydrogen pass through the catalyst bed in the reactor. Under the action of the hydrorefining catalyst, the non-hydrocarbon compounds such as sulfur, nitrogen and oxygen contained in the oil are converted into corresponding hydrocarbons and easily removed hydrogen sulfide, ammonia and water.

[0027] Hydrocracking: Under high pressure, hydrocarbon molecules undergo cracking and hydrogenation reactions with hydrogen on the catalyst surface to produce smaller molecules;

[0028] No. 3 jet fuel: No. 3 jet fuel that meets the requirements of GB6537-2018.

[0029] As described in the background section of this invention, existing technologies suffer from several drawbacks: the product characteristics of direct coal liquefaction kerosene fractions and indirect coal liquefaction kerosene fractions are not fully utilized, and the process routes require a large number of equipment units, resulting in high investment costs. To address these issues, in a typical embodiment of this invention, a coal-based jet fuel is provided. This coal-based jet fuel comprises direct coal liquefaction kerosene fractions, indirect coal liquefaction kerosene fractions, and additives. The boiling range of the direct coal liquefaction kerosene fraction is 120–300°C, and the boiling range of the indirect coal liquefaction kerosene fraction is 160–280°C.

[0030] The coal-based jet fuel provided by this invention comprises direct coal liquefaction kerosene fraction, indirect coal liquefaction kerosene fraction, and additives. During their research, the inventors unexpectedly discovered that the direct coal liquefaction kerosene fraction with a distillation range of 120–300℃ possesses characteristics such as high density, high thermal stability, high thermal oxidation stability, high flash point, low freezing point, high specific heat capacity, high calorific value, and richness in cycloalkanes and hydrogenated aromatics. The indirect coal liquefaction kerosene fraction with a distillation range of 160–280℃ possesses characteristics such as low sulfur content, low aromatic content, low nitrogen content, low ash content, high cetane number, high smoke point, and high net calorific value, but relatively lower density, lower flash point, and higher freezing point. The mixed fraction obtained by combining the above-mentioned direct coal liquefaction kerosene fraction and indirect coal liquefaction kerosene fraction can balance and fully utilize the density, flash point, freezing point, smoke point, and net calorific value characteristics of both, while maintaining low sulfur, nitrogen, and aromatic content, making it an excellent jet fuel. Among them, the kerosene fractions from direct coal liquefaction and indirect coal liquefaction can be prepared using existing production processes. They are widely available and easily obtained from the market, eliminating the need for new equipment or production processes, thus effectively reducing production costs.

[0031] Secondly, selecting direct coal liquefaction kerosene fractions with a distillation range of 120–300℃ and indirect coal liquefaction kerosene fractions with a distillation range of 160–280℃ can further improve the volumetric specific heat capacity and volumetric calorific value of coal-based jet fuels, while reducing their freezing point and aromatic content. When the initial boiling point of the direct coal liquefaction kerosene fraction is below 120℃, it contains more light components, has a lower density, and poorer stability, resulting in poorer stability of the obtained coal-based jet fuel. Conversely, when the final boiling point of the direct coal liquefaction kerosene fraction is above 300℃, it contains more heavy components, has a higher freezing point, and results in poorer low-temperature flow characteristics of the obtained coal-based jet fuel. When the initial boiling point of the coal-to-liquids kerosene fraction is below 160℃, the naphtha content in the fraction is high and easily volatilized, resulting in poor stability of the coal-based jet fuel. When the final boiling point of the coal-to-liquids kerosene fraction is above 280℃, the fraction contains more heavy components and has a high freezing point, resulting in poor low-temperature flow characteristics of the coal-based jet fuel. Furthermore, the addition of additives helps to clean the fuel system, improve fuel quality, and ensure that the relevant parameters of the coal-based jet fuel meet the requirements of No. 3 jet fuel. Any additives of conventional types in the art that can achieve the above-mentioned effects can be used in this invention.

[0032] This invention combines the characteristics of direct coal liquefaction kerosene fractions and indirect coal liquefaction kerosene fractions with specific distillation ranges, and utilizes additives in synergistic effects to obtain a coal-based jet fuel that is low-cost, high-performance, and meets the requirements for No. 3 jet fuel. Furthermore, the direct and indirect coal liquefaction kerosene fractions used in this coal-based jet fuel can be prepared using existing production processes, eliminating the need for additional equipment outside of existing production lines. This coal-based jet fuel production process requires less equipment and has lower investment costs, significantly reducing production costs and giving it a competitive edge in the market.

[0033] In a preferred embodiment, the initial boiling point of the direct coal liquefaction kerosene fraction is 120–160°C, and the final boiling point is 280–300°C. The direct coal liquefaction kerosene fraction meeting these conditions has a higher volumetric specific heat capacity and a higher volumetric calorific value, while also having a higher flash point and a lower freezing point, thus enabling better synergy with the indirect coal liquefaction kerosene fraction to improve the performance of coal-based jet fuel. For similar reasons, it is further preferred that the boiling range of the direct coal liquefaction kerosene fraction is 150–290°C; more preferably, the initial boiling point of the direct coal liquefaction kerosene fraction is 150–160°C, and the final boiling point is 280–290°C. Using the direct coal liquefaction kerosene fraction within this boiling range can further improve the volumetric specific heat capacity and volumetric calorific value of the coal-based jet fuel.

[0034] In a preferred embodiment, the initial boiling point of the coal-to-liquids kerosene fraction is 160–175°C, and the final boiling point is 260–280°C. Coal-to-liquids kerosene fraction meeting these conditions has lower sulfur content, lower nitrogen content, lower aromatic content, and lower cost. For similar reasons, it is further preferred that the boiling range of the coal-to-liquids kerosene fraction is 170–270°C; more preferably, the initial boiling point of the coal-to-liquids kerosene fraction is 170–175°C, and the final boiling point is 260–270°C. Using the coal-to-liquids kerosene fraction within this boiling range can further reduce the sulfur, nitrogen, and aromatic impurities in the coal-based jet fuel, enabling the obtained coal-based jet fuel to better meet the requirements for clean fuel.

[0035] To further synergize the direct coal liquefaction kerosene fraction and the indirect coal liquefaction kerosene fraction to obtain jet fuel with density, smoke point, and net calorific value that better meet the requirements of No. 3 jet fuel, in a preferred embodiment, the mass ratio of the direct coal liquefaction kerosene fraction to the indirect coal liquefaction kerosene fraction is (15:85) to (85:15); preferably (40:60) to (60:40). Under the above conditions, the density, flash point, freezing point, and sulfur, nitrogen, and aromatic hydrocarbon content values ​​of the direct coal liquefaction kerosene fraction and the indirect coal liquefaction kerosene fraction are complementary. With both contents controlled within the above range, the resulting jet fuel has a flash point, freezing point, density, and sulfur, nitrogen, and aromatic hydrocarbon content that is more suitable for jet fuel, resulting in better overall performance of the jet fuel and further improving the quality qualification rate of jet fuel.

[0036] In a preferred embodiment, the additives include antistatic agents and / or anti-wear agents. For the specific coal-to-direct liquefaction kerosene fraction and coal-to-indirect liquefaction kerosene fraction of this invention, to further improve the conductivity of the jet fuel and more effectively reduce safety risks, preferably, the antistatic agent is one or more of Stadis450, T1501, and T1502; to further improve the anti-wear index of the jet fuel and more effectively prevent excessive frictional damage in the gaps, the anti-wear agent is one or more of T1602, T1601, T305, and T306. The above-mentioned antistatic agents and anti-wear agents can provide better antistatic and anti-wear effects, have better compatibility with the coal-to-direct liquefaction kerosene fraction and coal-to-indirect liquefaction kerosene fraction of this invention, and can further improve the safety and stability of the fuel. To ensure the synergistic effect of various additives and further improve the quality of coal-based jet fuel, preferably, the solid-liquid ratio of the antistatic agent to the mixed fraction is 0.5–3.0 mg / L, more preferably 1–2 mg / L; the solid-liquid ratio of the anti-wear agent to the mixed fraction is 2–25 mg / L, more preferably 10–20 mg / L. The antistatic agent affects the product's water separation index, while the anti-wear agent affects the product's wear mark diameter. Under the above conditions, the product has a higher water separation index, a smaller wear mark diameter, and better overall performance.

[0037] In another typical embodiment of the present invention, a method for preparing the coal-based jet fuel described above is also provided. This method involves mixing direct coal liquefaction kerosene fraction, indirect coal liquefaction kerosene fraction, and additives to obtain the coal-based jet fuel. This method utilizes widely available and easily obtained components, and the resulting product meets the requirements for No. 3 jet fuel. Furthermore, the fractions used in the above preparation method can be obtained using existing production equipment, eliminating the need for additional equipment outside of existing production lines. This production process requires less equipment, has lower investment costs, and is more competitive in the market.

[0038] To ensure a more uniform and thorough mixing of the direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, and the additives, in a preferred embodiment, the mixing method is tank blending or pipeline blending. Preferably, tank blending is one or more of compressed air blending, mechanical stirring blending, and pump circulation blending. More preferably, when the mixing method is compressed air blending, the air source pressure is 0.3–0.6 MPa, the pulse frequency is 5–20 times / minute, and the injection time is 0.5–2 seconds / injection; and / or when the mixing method is mechanical stirring blending, the stirring speed is 300–500 rpm, and the stirring time is 20–50 minutes; and / or when the mixing method is pump circulation blending, the pump flow rate is 20–50 m³ / min. 3 / h.

[0039] In the preparation method provided by this invention, the coal direct liquefaction kerosene fraction used can be a conventional product prepared by those skilled in the art using existing processes. For the purpose of further reducing fuel costs and improving jet fuel performance, this invention preferably uses the following specific method to prepare the coal direct liquefaction kerosene fraction. In a preferred embodiment, the coal direct liquefaction kerosene fraction is prepared through the following steps: Step S11, the coal direct liquefaction crude oil is subjected to a hydrogenation stabilization reaction to obtain a first intermediate product of coal direct liquefaction; Step S12, the first intermediate product of coal direct liquefaction is subjected to a first fractionation to obtain a second intermediate product of coal direct liquefaction, the second intermediate product of coal direct liquefaction having a distillation range of 120–300°C; Step S13, the second intermediate product of coal direct liquefaction is subjected to a first hydrogenation refining reaction and a first hydrogenation cracking reaction sequentially to obtain a third intermediate product of coal direct liquefaction; Step S14, the third intermediate product of coal direct liquefaction is subjected to a second fractionation to obtain the aforementioned coal direct liquefaction kerosene fraction.

[0040] It should be noted that the aforementioned crude oil from direct coal liquefaction refers to the product obtained by reacting coal in a direct liquefaction reactor. The crude oil from direct coal liquefaction of this invention can be prepared using process conditions commonly used in coal liquefaction. After hydrostabilization, the crude oil undergoes hydrorefining to remove sulfur, nitrogen, oxygen, and metallic impurities, improving its color, acid value, and smoke point. Then, hydrocracking is performed, causing the large hydrocarbon molecules in the oil to crack and transform into light oil products such as gasoline, kerosene, and diesel. Finally, fractionation is carried out to obtain specific fractions of kerosene. Through a series of hydrotreating processes, the sulfur, nitrogen, and aromatic hydrocarbon content in the crude oil from direct coal liquefaction is reduced, and the kerosene fraction from direct coal liquefaction exhibits higher density, lower density, higher net calorific value, and higher flash point.

[0041] To further improve the density, net calorific value, flash point, and other properties of direct coal liquefaction kerosene fractions, thereby better synergistically enhancing the performance of coal-based jet fuels with indirect coal liquefaction kerosene fractions, in a preferred embodiment, in step S11, the reaction temperature of the hydrogenation stabilization reaction is 360–390°C, preferably 360–375°C; and / or the reaction pressure is 11–14 MPa, preferably 12–14 MPa; and / or the volume hourly space velocity is 0.5–2 h⁻¹. -1 Preferably, it is 0.8 to 1.2 hours. -1 The hydrogen-to-oil ratio is 300–700, preferably 400–600; in step S12, the reaction pressure of the first fractionation is 0.4–0.6 MPa; in step S13, the reaction temperature of the first hydrorefining reaction is 300–400 °C, preferably 330–370 °C; and / or the reaction pressure is 8–15 MPa, preferably 10–12 MPa; and / or the volume hourly space velocity is 0.5–3 h⁻¹. -1 Preferably 0.5 to 1 hour -1 The hydrogen-to-oil ratio is 200–600, preferably 200–500; in step S13, the reaction temperature of the first hydrocracking reaction is 310–400°C, preferably 330–380°C; the reaction pressure is 6–14 MPa, preferably 11–13 MPa; and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 Preferably 1 to 1.5 hours -1 The hydrogen-to-oil ratio is 200–800, preferably 400–600; in step S14, the second fractionation is carried out in the first fractionation column, the bottom temperature of the first fractionation column is 300–360°C, preferably 310–340°C; and / or the top temperature is 100–160°C, preferably 110–140°C; and / or the bottom pressure is 0.1–1.1 MPa, preferably 0.2–0.6 MPa.

[0042] Controlling the process conditions during hydrorefining and hydrocracking within the aforementioned ranges is more conducive to a more complete hydrogenation reaction, further removing heteroatoms from the crude oil from direct coal liquefaction, further promoting aromatic saturation in the crude oil, and further facilitating the conversion of the crude oil into smaller molecule oils. Controlling the process conditions during fractionation within the aforementioned ranges is also more conducive to improving the density, net calorific value, and flash point of the kerosene fraction from direct coal liquefaction.

[0043] In the preparation method provided by this invention, the coal-to-liquid kerosene fraction used can be a conventional product prepared by those skilled in the art using existing processes. However, for the purpose of further reducing fuel costs and improving jet fuel performance, this invention preferably uses the following specific method to prepare the coal-to-liquid kerosene fraction. In a preferred embodiment, the coal-to-liquid kerosene fraction is prepared through the following steps: Step S21, subjecting crude Fischer-Tropsch synthetic oil to a second hydrorefining reaction to obtain a first intermediate product of coal-to-liquid liquefaction; Step S22, subjecting the first intermediate product of coal-to-liquid liquefaction to a third fractionation to obtain a second intermediate product of coal-to-liquid liquefaction, the second intermediate product having a distillation range of 160–310°C; Step S23, subjecting the second intermediate product of coal-to-liquid liquefaction to a second hydrocracking reaction to obtain a third intermediate product of coal-to-liquid liquefaction; Step S24, subjecting the third intermediate product of coal-to-liquid liquefaction to a fourth fractionation to obtain the coal-to-liquid kerosene fraction.

[0044] It should be noted that the aforementioned Fischer-Tropsch crude oil refers to the oil product prepared by the Fischer-Tropsch reactor reaction of syngas. The Fischer-Tropsch crude oil of this invention can be prepared using process conditions commonly used in coal liquefaction. The Fischer-Tropsch crude oil first undergoes a hydrorefining reaction to remove most of the olefins, oxygen, and gums, and partially saturates the polycyclic aromatic hydrocarbons. The hydrorefining product is fractionated to obtain a hydrorefined product with a distillation range of 160–310°C. This fraction is then fed into a hydrocracking reaction zone for hydrocarbon cracking. The cracking product is further fractionated in a fractionating tower to obtain coal-to-liquid kerosene fraction. After a series of hydrotreating processes, the sulfur, nitrogen, and aromatic hydrocarbon contents of the Fischer-Tropsch crude oil are reduced. Using the aforementioned preparation conditions, the freezing point of the coal-to-liquid kerosene fraction can be further lowered.

[0045] The coal-to-oil indirect liquefaction fraction provided by this invention can be produced using conventional process conditions in the coal-to-oil indirect liquefaction process of the oil refining industry. To further remove impurities such as sulfur, nitrogen, and oxygen from the crude Fischer-Tropsch synthesis oil, and to further increase the flash point and decrease the freezing point of the coal-to-oil indirect liquefaction fraction, in a preferred embodiment, in step S21, the reaction temperature of the second hydrorefining reaction is 270–360°C, and / or the reaction pressure is 2–8 MPa, and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 The hydrogen-to-oil ratio is 200–700, preferably, the reaction temperature of the second hydrorefining reaction is 290–330°C, and / or the reaction pressure is 2–6 MPa, and / or the volume hourly space velocity is 0.5–2 h⁻¹. -1The hydrogen-to-oil ratio is 250–500. In step S22, the number of trays in the third fractionation is 50–70; and / or the reflux ratio is (3–5):1; and / or the operating pressure is 0.5–1.5 MPa; and / or the bottom temperature is 300–350 °C. In step S23, the reaction temperature of the second hydrocracking reaction is 300–380 °C, and / or the reaction pressure is 2–10 MPa, and / or the volume hourly space velocity is 0.5–4 h⁻¹. -1 The hydrogen-to-oil ratio is 200–800; preferably, the reaction temperature of the second hydrocracking reaction is 300–350°C, and / or the reaction pressure is 3–6 MPa, and / or the volume hourly space velocity is 0.5–1.5 h⁻¹. -1 The hydrogen-to-oil ratio is 300–600. In step S24, the fourth fractionation is carried out in the second fractionation column, which has 50–70 trays; and / or a reflux ratio of (3–5):1; and / or a bottom temperature of 290–370°C; and / or a top temperature of 100–150°C; and / or a bottom pressure of 0.1–1.1 MPa. Preferably, the bottom temperature of the second fractionation column is 290–330°C; and / or a top temperature of 100–130°C; and / or a bottom pressure of 0.15–0.5 MPa.

[0046] Controlling the process conditions during hydrorefining and hydrocracking within the aforementioned ranges can facilitate a more complete hydrogenation reaction and more effectively achieve olefin saturation and oxide removal in the coal-to-liquids kerosene fraction. Controlling the process conditions during fractionation within the aforementioned ranges further reduces the aromatic content in the coal-to-liquids kerosene fraction.

[0047] Typical, but not limiting, the initial boiling point of coal direct liquefaction kerosene fraction is 120℃, 130℃, 140℃, 150℃, 160℃ or any two of these values, and the final boiling point is 280℃, 290℃, 300℃ or any two of these values.

[0048] Typical, but not limiting, the initial boiling point of coal-to-oil indirect liquefaction fractions is 160℃, 165℃, 170℃, 175℃ or any two of these values, and the final boiling point is 260℃, 265℃, 170℃, 175℃, 280℃ or any two of these values.

[0049] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0050] Example 1

[0051] See the process flow diagram for coal-based jet fuel preparation. Figure 1The feedstock for direct coal liquefaction includes coal (bituminous coal), solvent (hydrogenated stabilized circulating solvent oil), and catalyst (FeOOH and a small amount of ammonium sulfate). The feedstock for indirect coal liquefaction includes coal, hydrogen, carbon monoxide, and catalyst (iron oxide-based catalyst).

[0052] After the coal direct liquefaction feedstock 14 reacts in the coal direct liquefaction reactor 1, the resulting coal direct liquefaction crude oil is purified at a temperature of 375℃, a reaction pressure of 12MPa, and a volume hourly space velocity of 1.2h⁻¹. -1 After stabilization in hydrotreating reactor 2 with a hydrogen-to-oil ratio of 500, the product enters the first intermediate fractionation tower 3 at a pressure of 0.5 MPa for fractionation, yielding a hydrotreated feedstock with a distillation range of 120–300 °C. The hydrotreated feedstock is then subjected to further distillation at 350 °C, a pressure of 11 MPa, and a volumetric hourly space velocity (VHSV) of 0.75 h⁻¹. -1 The hydrogenation refining reaction was carried out in a first hydrorefining reactor 4 with a hydrogen-to-oil ratio of 350:1; then, the reaction was carried out at a temperature of 355℃, a pressure of 12MPa, and a volume hourly space velocity of 1.25h⁻¹. -1 Hydrocracking is carried out in a first hydrocracking reactor 5 with a hydrogen-to-oil ratio of 500:1. The hydrocracking products are then fed into a first fractionation tower 6 for separation. The bottom temperature of the first fractionation tower is 325℃, the top temperature is 125℃, and the bottom pressure is 0.4MPa. A coal direct liquefaction kerosene fraction with an initial boiling point of 155℃ and a final boiling point of 285℃ is obtained, with a boiling range of 155~285℃.

[0053] After the coal indirect liquefaction feedstock 15 reacts in the Fischer-Tropsch synthesis reactor 7, the resulting product is fractionated in a second intermediate fractionation tower 8 at a pressure of 1.5 MPa to obtain Fischer-Tropsch crude oil containing heavy components with a distillation range of 150–650 °C. This Fischer-Tropsch crude oil is then passed through a second hydrorefining reactor 9 at a reaction temperature of 310 °C, a pressure of 4 MPa, and a volume hourly space velocity of 1.25 h⁻¹. -1 The hydrogen-to-oil ratio is 375:1 in a fractionation column for hydrorefining. The resulting hydrorefined product enters the third intermediate fractionation column 10 for fractionation under the following conditions: 60 trays, reflux ratio of 4:1, operating pressure of 1.0 MPa, and bottom temperature of 325°C. After removing the top and side stream products 16 from the fractionation column, the hydrorefined tail oil with a distillation range of 150–600°C is sent to the second hydrocracking reactor 11, where it is subjected to hydrocracking at 325°C, pressure of 4.5 MPa, and volumetric hourly space velocity of 1 h⁻¹. -1 Hydrocracking was carried out under a hydrogen-to-oil ratio of 450:1. The hydrocracking products were separated in the second fractionation column 12 under the following conditions: 60 trays, reflux ratio of 4:1, bottom temperature of 310℃, top temperature of 115℃, and bottom pressure of 0.325 MPa. A coal-to-oil indirect liquefaction kerosene fraction with an initial boiling point of 170℃ and a final boiling point of 270℃ was obtained, with a boiling range of 170–270℃.

[0054] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 50:50 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1602. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 1.5 mg / L to the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 15 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, Stadis450 and T1602 weighed according to the above proportions are mechanically stirred and blended at a speed of 400 rpm for 35 minutes to obtain coal-based jet fuel 18.

[0055] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 1.

[0056] Example 2

[0057] The only difference from Example 1 is:

[0058] After the coal direct liquefaction feedstock 14 reacts in the coal direct liquefaction reactor 1, the resulting coal direct liquefaction crude oil is purified at a temperature of 360℃, a reaction pressure of 14MPa, and a volume hourly space velocity of 0.5h⁻¹. -1 After stabilization in the hydrostabilization reactor 2 with a hydrogen-to-oil ratio of 700, the product enters the first intermediate fractionation tower 3 at a pressure of 0.4 MPa for fractionation, yielding a hydrostabilized feedstock with a distillation range of 120–300 °C. This hydrostabilized feedstock is then subjected to further distillation at a temperature of 330 °C, a pressure of 10 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 The hydrorefining reaction is carried out in the first hydrorefining reactor 4 with a hydrogen-to-oil ratio of 200:1; then the reaction is carried out at a temperature of 330℃, a pressure of 11MPa, and a volume hourly space velocity of 1h. -1 Hydrocracking is carried out in a first hydrocracking reactor 5 with a hydrogen-to-oil ratio of 400:1. The hydrocracking products are then fed into a first fractionation tower 6 for separation. The bottom temperature of the first fractionation tower is 310℃, the top temperature is 110℃, and the bottom pressure is 0.2MPa. A coal direct liquefaction kerosene fraction with an initial boiling point of 150℃ and a final boiling point of 280℃ is obtained, with a boiling range of 150–280℃.

[0059] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 2.

[0060] Example 3

[0061] The only difference from Example 1 is:

[0062] After the coal direct liquefaction feedstock 14 is reacted in the coal direct liquefaction reactor 1, the resulting coal direct liquefaction crude oil is purified at a temperature of 390℃, a reaction pressure of 11MPa, and a volume hourly space velocity of 2h. -1 After stabilization in the hydrostabilization reactor 2 with a hydrogen-to-oil ratio of 300, the product enters the first intermediate fractionation tower 3 at a pressure of 0.6 MPa for fractionation, yielding a hydrostabilized feedstock with a distillation range of 120–300 °C. This hydrostabilized feedstock is then subjected to further distillation at a temperature of 370 °C, a pressure of 12 MPa, and a volume hourly space velocity (VHSV) of 1 h⁻¹. -1 The hydrogenation refining reaction was carried out in a first hydrorefining reactor 4 with a hydrogen-to-oil ratio of 500:1; then, the reaction was carried out at a temperature of 380℃, a pressure of 13MPa, and a volume hourly space velocity of 1.5h⁻¹. -1 Hydrocracking is carried out in a first hydrocracking reactor 5 with a hydrogen-to-oil ratio of 600:1. The hydrocracking products are then fed into a first fractionation tower 6 for separation. The bottom temperature of the first fractionation tower is 340℃, the top temperature is 140℃, and the bottom pressure is 0.6MPa. A coal direct liquefaction kerosene fraction with an initial boiling point of 160℃ and a final boiling point of 290℃ is obtained, with a boiling range of 160–290℃.

[0063] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 3.

[0064] Example 4

[0065] The only difference from Example 1 is:

[0066] After the coal direct liquefaction feedstock 14 reacts in the coal direct liquefaction reactor 1, the resulting coal direct liquefaction crude oil is purified at a temperature of 360℃, a reaction pressure of 14MPa, and a volume hourly space velocity of 0.8h. -1 After stabilization in the hydrotreating reactor 2 with a hydrogen-to-oil ratio of 600, the product enters the first intermediate fractionation tower 3 at a pressure of 0.6 MPa for fractionation, yielding a hydrotreated stable feedstock with a distillation range of 120–300 °C. This hydrotreated stable feedstock is then subjected to distillation at a temperature of 300 °C, a pressure of 8 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 The hydrorefining reaction was carried out in a first hydrorefining reactor 4 with a hydrogen-to-oil ratio of 200:1; then, the reaction was carried out at a temperature of 310℃, a pressure of 6 MPa, and a volumetric hourly space velocity of 0.5 h⁻¹. -1 Hydrocracking is carried out in a first hydrocracking reactor 5 with a hydrogen-to-oil ratio of 200:1. The hydrocracking products are then fed into a first fractionation tower 6 for separation. The bottom temperature of the first fractionation tower is 300℃, the top temperature is 100℃, and the bottom pressure is 0.1MPa. A coal direct liquefaction kerosene fraction with an initial boiling point of 120℃ and a final boiling point of 280℃ is obtained, with a boiling range of 120–280℃.

[0067] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 4.

[0068] Example 5

[0069] The only difference from Example 1 is:

[0070] After the coal direct liquefaction feedstock 14 reacts in the coal direct liquefaction reactor 1, the resulting coal direct liquefaction crude oil is purified at a temperature of 375℃, a reaction pressure of 12MPa, and a volume hourly space velocity of 1.2h⁻¹. -1 After stabilization in the hydrostabilization reactor 2 with a hydrogen-to-oil ratio of 400, the feedstock enters the first intermediate fractionation tower 3 at a pressure of 0.4 MPa for fractionation, yielding a hydrostabilized feedstock with a distillation range of 120–300 °C. The hydrostabilized feedstock is then subjected to distillation at a temperature of 400 °C, a pressure of 15 MPa, and a volume hourly space velocity of 3 h⁻¹. -1 The hydrorefining reaction is carried out in the first hydrorefining reactor 4 with a hydrogen-to-oil ratio of 600:1; then the reaction is carried out at a temperature of 400℃, a pressure of 14MPa, and a volume hourly space velocity of 4h. -1 The hydrocracking reaction takes place in a first hydrocracking reactor 5 with a hydrogen-to-oil ratio of 800:1. The hydrocracking products are then fed into a first fractionation tower 6 for separation. The bottom temperature of the first fractionation tower is 360℃, the top temperature is 160℃, and the bottom pressure is 1.1MPa. A coal direct liquefaction kerosene fraction with an initial boiling point of 160℃ and a final boiling point of 300℃ is obtained, with a boiling range of 160–300℃.

[0071] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 5.

[0072] Example 6

[0073] The only difference from Example 1 is:

[0074] After the coal indirect liquefaction feedstock 15 reacts in the Fischer-Tropsch synthesis reactor 7, the resulting product is fractionated in a second intermediate fractionation tower 8 at a pressure of 1.5 MPa to obtain Fischer-Tropsch crude oil containing heavy components with a distillation range of 150–650 °C. This Fischer-Tropsch crude oil is then passed through a second hydrorefining reactor 9 at a reaction temperature of 270 °C, a pressure of 2 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1 in a fractionation column for hydrorefining. The resulting hydrorefined product enters the third intermediate fractionation column 10 for fractionation under the following conditions: 50 trays, reflux ratio of 3:1, operating pressure of 0.5 MPa, and bottom temperature of 300°C. After removing the top and side stream products 16 from the fractionation column, the hydrorefined tail oil with a distillation range of 150–600°C is sent to the second hydrocracking reactor 11, where it is processed at 300°C, pressure of 2 MPa, and volume hourly space velocity of 0.5 h⁻¹. -1Hydrocracking was carried out under a hydrogen-to-oil ratio of 200:1. The hydrocracking products were separated in the second fractionating column 12 under the following conditions: 60 trays, reflux ratio of 3:1, bottom temperature of 290℃, top temperature of 100℃, and bottom pressure of 0.1MPa. A coal-to-oil indirect liquefaction kerosene fraction with an initial boiling point of 160℃ and a final boiling point of 260℃ was obtained, with a boiling range of 160–260℃.

[0075] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 6.

[0076] Example 7

[0077] The only difference from Example 1 is:

[0078] After the coal indirect liquefaction feedstock 15 reacts in the Fischer-Tropsch synthesis reactor 7, the resulting product is fractionated in a second intermediate fractionation tower 8 at a pressure of 1.5 MPa to obtain Fischer-Tropsch crude oil containing heavy components with a distillation range of 150–650 °C. This Fischer-Tropsch crude oil is then passed through a second hydrorefining reactor 9 at a reaction temperature of 360 °C, a pressure of 8 MPa, and a volume hourly space velocity of 4 h⁻¹. -1 The hydrogen-to-oil ratio is 700:1 in a fractionation column for hydrorefining. The resulting hydrorefined product enters the third intermediate fractionation column 10 for fractionation under the following conditions: 60 trays, reflux ratio of 3:1, operating pressure of 0.8 MPa, and bottom temperature of 325°C. After the top and side stream products 16 are extracted from the fractionation column, the hydrorefined tail oil with a distillation range of 150–600°C is sent to the second hydrocracking reactor 11, where it is subjected to hydrocracking at a temperature of 380°C, a pressure of 10 MPa, and a volume hourly space velocity of 4 h⁻¹. -1 Hydrocracking was carried out under a hydrogen-to-oil ratio of 800:1. The hydrocracking products were separated in the second fractionating column 12 under the following conditions: 60 trays, reflux ratio of 3:1, bottom temperature of 370℃, top temperature of 150℃, and bottom pressure of 1.1 MPa. A coal-to-oil indirect liquefaction kerosene fraction was obtained with an initial boiling point of 175℃ and a final boiling point of 280℃, with a boiling range of 175–280℃.

[0079] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 7.

[0080] Example 8

[0081] The only difference from Example 1 is:

[0082] After the coal indirect liquefaction feedstock 15 reacts in the Fischer-Tropsch synthesis reactor 7, the resulting product is fractionated in a second intermediate fractionation tower 8 at a pressure of 1.5 MPa to obtain Fischer-Tropsch crude oil containing heavy components with a distillation range of 150–650 °C. This Fischer-Tropsch crude oil is then passed through a second hydrorefining reactor 9 at a reaction temperature of 290 °C, a pressure of 2 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 The hydrogen-to-oil ratio is 250:1 in a fractionation column for hydrorefining. The resulting hydrorefined product enters the third intermediate fractionation column 10 for fractionation under the following conditions: 50 trays, reflux ratio of 5:1, operating pressure of 0.8 MPa, and bottom temperature of 320°C. After removing the top and side stream products 16 from the fractionation column, the hydrorefined tail oil with a distillation range of 150–600°C is sent to the second hydrocracking reactor 11, where it is processed at 300°C, 3 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 Hydrocracking was carried out under a hydrogen-to-oil ratio of 300:1. The hydrocracking products were separated in the second fractionating column 12 under the following conditions: 60 trays, reflux ratio of 4:1, bottom temperature of 290℃, top temperature of 100℃, and bottom pressure of 0.15MPa. A coal-to-oil indirect liquefaction kerosene fraction with an initial boiling point of 170℃ and a final boiling point of 260℃ was obtained, with a boiling range of 170–260℃.

[0083] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 8.

[0084] Example 9

[0085] The only difference from Example 1 is:

[0086] After the coal indirect liquefaction feedstock 15 reacts in the Fischer-Tropsch synthesis reactor 7, the resulting product is fractionated in a second intermediate fractionation tower 8 at a pressure of 1.5 MPa to obtain Fischer-Tropsch crude oil containing heavy components with a distillation range of 150–650 °C. This Fischer-Tropsch crude oil is then passed through a second hydrorefining reactor 9 at a reaction temperature of 330 °C, a pressure of 6 MPa, and a volume hourly space velocity of 2 h⁻¹. -1 The hydrogen-to-oil ratio is 500:1 in a fractionation column for hydrorefining. The resulting hydrorefined product enters the third intermediate fractionation column 10 for fractionation under the following conditions: 70 trays, reflux ratio of 3:1, operating pressure of 0.8 MPa, and bottom temperature of 315°C. After removing the top and side stream products 16 from the fractionation column, the hydrorefined tail oil with a distillation range of 150–600°C is sent to the second hydrocracking reactor 11, where it is processed at 350°C, 6 MPa, and a volume hourly space velocity of 1.5 h⁻¹. -1Hydrocracking was carried out under a hydrogen-to-oil ratio of 600:1. The hydrocracking products were separated in the second fractionating column 12 under the following conditions: 60 trays, reflux ratio of 3:1, bottom temperature of 330℃, top temperature of 130℃, and bottom pressure of 0.5MPa. A coal-to-oil indirect liquefaction kerosene fraction with an initial boiling point of 175℃ and a final boiling point of 260℃ was obtained, with a boiling range of 175–260℃.

[0087] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 9.

[0088] Example 10

[0089] The only difference from Example 1 is:

[0090] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 40:60 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1602. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 2 mg / L to the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 20 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, Stadis450 and T1602 weighed according to the above proportions are stirred at a speed of 300 rpm for 50 minutes to obtain coal-based jet fuel 18.

[0091] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 10.

[0092] Example 11

[0093] The only difference from Example 1 is:

[0094] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 60:40 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1602. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 1 mg / L to the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 10 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, Stadis450 and T1602 weighed according to the above proportions are stirred at a speed of 500 rpm for 20 minutes to obtain coal-based jet fuel 18.

[0095] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 11.

[0096] Example 12

[0097] The only difference from Example 1 is:

[0098] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 15:85 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include T1501 and T1602. A certain amount of T1501 is weighed according to a solid-liquid ratio of 0.5 mg / L between T1501 and the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 25 mg / L between T1602 and the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, T1501 and T1602 weighed according to the above proportions are stirred at a speed of 500 rpm for 20 minutes to obtain coal-based jet fuel 18.

[0099] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 12.

[0100] Example 13

[0101] The only difference from Example 1 is:

[0102] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 85:15 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1601. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 3 mg / L to the mixed fraction, and a certain amount of T1601 is weighed according to a solid-liquid ratio of 2 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, Stadis450 and T1601 weighed according to the above proportions are stirred at a speed of 300 rpm for 50 minutes to obtain coal-based jet fuel 18.

[0103] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 13.

[0104] Example 14

[0105] The only difference from Example 1 is:

[0106] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 50:50 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include T1501 and T1601. A certain amount of T1501 is weighed according to a solid-liquid ratio of 1.5 mg / L between T1501 and the mixed fraction, and a certain amount of T1601 is weighed according to a solid-liquid ratio of 15 mg / L between T1601 and the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, T1501 and T1601 weighed according to the above proportions are blended with compressed air. The air source pressure is 0.4 MPa, the pulse frequency is 10 times / minute, and the injection time is 1 second / injection to obtain coal-based jet fuel 18.

[0107] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 14.

[0108] Example 15

[0109] The only difference from Example 1 is:

[0110] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 60:40 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1602. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 1 mg / L to the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 10 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, indirect coal liquefaction kerosene fraction, Stadis450 and T1602 weighed according to the above proportions are circulated and blended in a pump with a flow rate of 40 m³ / L. 3 / h, yielding coal-based jet fuel 18.

[0111] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 15.

[0112] Example 16

[0113] The only difference from Example 1 is:

[0114] The above-mentioned direct coal liquefaction kerosene fraction and the above-mentioned indirect coal liquefaction kerosene fraction are mixed at a mass ratio of 60:40 to obtain a mixed fraction. Additive 17 and the mixed fraction are mixed in mixer 13. The additives include Stadis450 and T1602. A certain amount of Stadis450 is weighed according to a solid-liquid ratio of 1 mg / L to the mixed fraction, and a certain amount of T1602 is weighed according to a solid-liquid ratio of 10 mg / L to the mixed fraction. The direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, Stadis450 and T1602 weighed according to the above proportions are blended in a pipeline to obtain coal-based jet fuel 18.

[0115] The properties of coal-based jet fuel, direct coal liquefaction kerosene fraction, and indirect coal liquefaction kerosene fraction are shown in Table 16.

[0116] Table 1

[0117]

[0118] Table 2

[0119]

[0120]

[0121] Table 3

[0122]

[0123]

[0124] Table 4

[0125]

[0126] Table 5

[0127]

[0128] Table 6

[0129]

[0130]

[0131] Table 7

[0132]

[0133]

[0134] Table 8

[0135]

[0136] Table 9

[0137]

[0138] Table 10

[0139]

[0140]

[0141] Table 11

[0142]

[0143]

[0144] Table 12

[0145]

[0146] Table 13

[0147]

[0148] Table 14

[0149]

[0150]

[0151] Table 15

[0152]

[0153]

[0154] Table 16

[0155]

[0156]

[0157] As can be seen from the above, the coal-based jet fuel indicators in the various embodiments of the present invention meet the standard requirements for No. 3 jet fuel and can be used as No. 3 jet fuel. The present invention directly blends direct coal liquefaction kerosene fraction and indirect coal liquefaction kerosene fraction to prepare coal-based jet fuel, fully utilizing the characteristics of both products. The resulting coal-based jet fuel meets the No. 3 jet fuel indicator requirements and can be directly put into use, which is beneficial for alleviating the energy crisis. Furthermore, the preparation method of the present invention is simple and can directly utilize existing processes to prepare direct coal liquefaction kerosene fraction and indirect coal liquefaction kerosene fraction, reducing the number of equipment and thus reducing investment costs, which is conducive to widespread application.

[0158] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing coal-based jet fuel, characterized in that, The coal-based jet fuel comprises a mixed fraction and additives. The mixed fraction includes direct coal liquefaction kerosene fraction and indirect coal liquefaction kerosene fraction. The direct coal liquefaction kerosene fraction has a boiling range of 120~300℃, and the indirect coal liquefaction kerosene fraction has a boiling range of 160~280℃. The mass ratio of the direct coal liquefaction kerosene fraction to the indirect coal liquefaction kerosene fraction is (15:85)~(85:15). The preparation method includes: mixing the direct coal liquefaction kerosene fraction, the indirect coal liquefaction kerosene fraction, and the additive to obtain the coal-based jet fuel; The coal direct liquefaction kerosene fraction is prepared through the following steps: Step S11: The crude oil from direct coal liquefaction is subjected to a hydrogenation stabilization reaction to obtain the first intermediate product of direct coal liquefaction. Step S12: The first intermediate product of direct coal liquefaction is subjected to a first fractionation to obtain a second intermediate product of direct coal liquefaction, wherein the distillation range of the second intermediate product of direct coal liquefaction is 120~300℃. Step S13: The second intermediate product of direct coal liquefaction is subjected to a first hydrorefining reaction and a first hydrocracking reaction in sequence to obtain the third intermediate product of direct coal liquefaction. Step S14: The third intermediate product of direct coal liquefaction is subjected to a second fractionation to obtain the direct coal liquefaction kerosene fraction; The coal indirect liquefaction kerosene fraction is prepared through the following steps: Step S21: The crude Fischer-Tropsch synthesis oil is subjected to a second hydrorefining reaction to obtain the first intermediate product of coal indirect liquefaction. Step S22: The first intermediate product of coal indirect liquefaction is subjected to a third fractionation to obtain the second intermediate product of coal indirect liquefaction, wherein the distillation range of the second intermediate product of coal indirect liquefaction is 160~310℃. Step S23: The second intermediate product of coal indirect liquefaction is subjected to a second hydrocracking reaction to obtain the third intermediate product of coal indirect liquefaction. Step S24: The third intermediate product of coal indirect liquefaction is subjected to a fourth fractionation to obtain the coal indirect liquefaction kerosene fraction.

2. The method for preparing coal-based jet fuel according to claim 1, characterized in that, The initial boiling point of the coal direct liquefaction kerosene fraction is 120~160℃, and the final boiling point is 280~300℃; and / or The initial boiling point of the coal-to-oil indirect liquefaction fraction is 160-175℃, and the final boiling point is 260-280℃.

3. The method for preparing coal-based jet fuel according to claim 1 or 2, characterized in that, The boiling range of the direct coal liquefaction kerosene fraction is 150~290℃; and / or The distillation range of the coal indirect liquefaction kerosene fraction is 170~270℃.

4. The method for preparing coal-based jet fuel according to claim 1 or 2, characterized in that, The initial boiling point of the coal direct liquefaction kerosene fraction is 150-160℃, and the final boiling point is 280-290℃; and / or The initial boiling point of the coal-to-oil indirect liquefaction fraction is 170-175℃, and the final boiling point is 260-270℃.

5. The method for preparing coal-based jet fuel according to claim 1 or 2, characterized in that, The mass ratio of the direct coal liquefaction kerosene fraction to the indirect coal liquefaction kerosene fraction is (40:60) to (60:40).

6. The method for preparing coal-based jet fuel according to claim 1 or 2, characterized in that, The additives include antistatic agents and / or anti-wear agents.

7. The method for preparing coal-based jet fuel according to claim 6, characterized in that, The antistatic agent is one or more of Stadis450, T1501, and T1502; and / or the solid-liquid ratio of the antistatic agent to the mixed fraction is 0.5~3.0 mg / L; and / or The anti-wear agent is one or more of T1602, T1601, T305 and T306; and / or the solid-liquid ratio of the anti-wear agent to the mixed fraction is 2~25 mg / L.

8. The method for preparing coal-based jet fuel according to claim 6, characterized in that, The solid-liquid ratio of the antistatic agent to the mixed fraction is 1~2 mg / L; and / or The solid-liquid ratio of the anti-wear agent to the mixed fraction is 10~20 mg / L.

9. The preparation method according to claim 1, characterized in that, The mixing method is either tank mixing or pipeline mixing.

10. The preparation method according to claim 9, characterized in that, The oil tank blending method is one or more of compressed air blending, mechanical stirring blending, and pump circulation blending.

11. The preparation method according to claim 10, characterized in that, When the mixing method is compressed air blending, the air source pressure is 0.3~0.6MPa, the pulse frequency is 5~20 times / minute, and the injection time is 0.5~2 seconds / injection; and / or When the mixing method is mechanical stirring, the stirring speed is 300-500 rpm, and the stirring time is 20-50 minutes; and / or When the mixing method is pump circulation and blending, the pump flow rate is 20~50m³. 3 / h.

12. The preparation method according to claim 1, characterized in that, In step S11, the reaction temperature of the hydrogenation stabilization reaction is 360~390℃; and / or the reaction pressure is 11~14MPa; and / or the volume hourly space velocity is 0.5~2h. -1 ; and / or the hydrogen-to-oil ratio is 300~700; In step S12, the reaction pressure of the first fractionation is 0.4~0.6 MPa; In step S13, the reaction temperature of the first hydrogenation refining reaction is 300~400℃; and / or the reaction pressure is 8~15MPa; and / or the volume hourly space velocity is 0.5~3h. -1 ; and / or the hydrogen-to-oil ratio is 200~600; In step S13, the reaction temperature of the first hydrocracking reaction is 310~400℃; and / or the reaction pressure is 6~14MPa; and / or the volume hourly space velocity is 0.5~4h. -1 ; and / or the hydrogen-to-oil ratio is 200~800; In step S14, the second fractionation is carried out in the first fractionation column, where the bottom temperature of the first fractionation column is 300~360℃; and / or the top temperature is 100~160℃; and / or the bottom pressure is 0.1~1.1MPa.

13. The preparation method according to claim 1, characterized in that, In step S11, the reaction temperature of the hydrogenation stabilization reaction is 360~375℃; and / or the reaction pressure is 12~14MPa; and / or the volume hourly space velocity is 0.8~1.2h. -1 ; and / or the hydrogen-to-oil ratio is 400~600; In step S13, the reaction temperature of the first hydrogenation refining reaction is 330~370℃; and / or the reaction pressure is 10~12MPa; and / or the volume hourly space velocity is 0.5~1h. -1 ; and / or the hydrogen-to-oil ratio is 200~500; In step S13, the reaction temperature of the first hydrocracking reaction is 330~380℃; and / or the reaction pressure is 11~13MPa; and / or the volume hourly space velocity is 1~1.5h. -1 ; and / or the hydrogen-to-oil ratio is 400~600; In step S14, the second fractionation is carried out in the first fractionation column, where the bottom temperature of the first fractionation column is 310~340℃; and / or the top temperature is 110~140℃; and / or the bottom pressure is 0.2~0.6MPa.

14. The preparation method according to claim 1, characterized in that, In step S21, the reaction temperature of the second hydrogenation refining reaction is 270~360℃; and / or the reaction pressure is 2~8MPa; and / or the volume hourly space velocity is 0.5~4h. -1 ; and / or the hydrogen-to-oil ratio is 200~700; In step S22, the number of trays in the third fractionation is 50-70; and / or the reflux ratio is (3-5):1; and / or the operating pressure is 0.5-1.5 MPa; and / or the bottom temperature is 300-350℃. In step S23, the reaction temperature of the second hydrocracking reaction is 300~380℃; and / or the reaction pressure is 2~10MPa; and / or the volume hourly space velocity is 0.5~4h. -1 ; and / or the hydrogen-to-oil ratio is 200~800; In step S24, the fourth fractionation is carried out in the second fractionation column, which has 50 to 70 trays; and / or a reflux ratio of (3 to 5):1; and / or a bottom temperature of 290 to 370°C; and / or a top temperature of 100 to 150°C; and / or a bottom pressure of 0.1 to 1.1 MPa.

15. The preparation method according to claim 1, characterized in that, In step S21, the reaction temperature of the second hydrogenation refining reaction is 290~330℃; and / or the reaction pressure is 2~6MPa; and / or the volume hourly space velocity is 0.5~2h. -1 ; and / or the hydrogen-to-oil ratio is 250~500; In step S23, the reaction temperature of the second hydrocracking reaction is 300~350℃; and / or the reaction pressure is 3~6MPa; and / or the volume hourly space velocity is 0.5~1.5h. -1 ; and / or the hydrogen-to-oil ratio is 300~600; In step S24, the fourth fractionation is carried out in the second fractionation column, where the bottom temperature of the second fractionation column is 290~330℃; and / or the top temperature is 100~130℃; and / or the bottom pressure is 0.15~0.5MPa.

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