A method for producing aviation fuel

Abstract

The present invention discloses a method for producing aviation kerosene. The method comprises the following steps: (1) aviation kerosene raw materials and hydrogen enter a mixing container, gasify, and obtain a gaseous mixture; (2) the gaseous mixture enters a first reactor after being pressurized, wherein the gaseous components are discharged upward from the first reactor, and the liquid components are subjected to hydrogenation reaction downward, and the first reactor effluent is obtained and discharged from the bottom of the first reactor; (3) the gaseous components are discharged from the first reactor and enter a second reactor, undergo a hydrogenation desulfurization reaction, and obtain a second reactor effluent; (4) the first reactor effluent and the second reactor effluent are stripped to obtain an aviation kerosene product. The present invention can produce high-quality aviation kerosene products with high smoke point and good lubricity under the conditions of simple process, low energy consumption, and low cost.

Description

Technical Field

[0001] The invention belongs to the field of clean oil refining, and in particular relates to a method for producing aviation kerosene. Background Art

[0002] Jet kerosene is one of the high value-added products in the oil refining industry. In recent years, with the general improvement in the quality of life, the development of China's civil aviation industry has been significantly accelerated, resulting in a growing demand for aviation fuel. In the face of the increasing demand for jet kerosene production, in order to increase the production of jet kerosene and comply with the development requirements of the industry, the main method for oil refining companies to increase the production of jet kerosene is to increase the production of jet kerosene by cutting the heavy straight-run kerosene fraction. However, the increase in the kerosene distillation range will increase the aromatic content in the kerosene fraction, which will cause the smoke point index of the jet kerosene product to be unqualified. The existing solution is to improve the properties of the jet kerosene product by increasing the severity of the reaction, such as increasing the reaction pressure, increasing the reaction temperature, reducing the reaction space velocity, etc., to reduce the aromatic content in the jet kerosene product, thereby achieving the purpose of improving the smoke point of the jet kerosene product. However, the pressure design level of the existing aviation kerosene device is relatively low, generally 3-4MPa, and aromatics hydrogenation under a fixed bed reaction environment requires a higher reaction pressure to achieve the aromatics hydrogenation reaction removal to the corresponding index requirements. The existing deep hydrogenation process uses straight-run kerosene fractions as raw materials to produce qualified aviation kerosene. The process undergoes deep desulfurization, denitrification and olefin saturation reactions, and aromatics are significantly reduced, and the combustion performance index of the oil product is significantly improved. However, since the sulfur content in the properties of aviation kerosene products is closely related to the lubricity of the product, if the sulfur content is removed to a too low level under harsh conditions, it will affect the lubricity index of the aviation kerosene product, and it is necessary to add anti-wear agents to the aviation kerosene product to improve it, which not only increases the energy consumption and hydrogen consumption in the production process, but also increases the difficulty of product blending at the factory. Therefore, although the terminal distillation point in the aviation kerosene quality index is limited to ≯300℃, in order to ensure the qualified smoke point index, oil refineries can only control the terminal distillation point of aviation kerosene at ≯260℃. However, the terminal distillation point is controlled too low, and the goal of reducing diesel and increasing aviation kerosene production cannot be achieved.

[0003] CN107233927A discloses a medium oil type hydrocracking catalyst and a preparation method thereof. The method mainly modifies the beta molecular sieve to make it have relatively balanced degradation performance, and can improve the smoke point of aviation kerosene products when producing intermediate distillate oil. However, the catalyst is used to produce aviation kerosene using conventional fixed bed hydrogenation process technology, and there are disadvantages in that the energy consumption and hydrogen consumption of the device are relatively large during the production process, and the aviation kerosene yield is low.

[0004] CN111088072A discloses a hydrocracking method for reducing the bromine index of heavy naphtha and increasing the smoke point of aviation kerosene. The method is to recycle the light aviation kerosene components rich in aromatics obtained by fractionation of the oil products after hydrofining and hydrocracking back to the hydrocracking device, and the components rich in paraffin obtained by fractionation are used as aviation kerosene products. However, the aviation kerosene yield produced by this method is low, the energy consumption of the device is large during the production process, and the product has a high content of paraffins, which easily causes the freezing point to be unqualified. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for producing aviation kerosene, which can produce high-quality aviation kerosene products with high smoke point and good lubrication performance under the conditions of simple process, low energy consumption and low cost.

[0006] The present invention provides a method for producing aviation fuel, comprising the following steps:

[0007] (1) The jet fuel raw material and hydrogen enter a mixing container and are gasified to obtain a gas phase mixture;

[0008] (2) The gas phase mixture is pressurized and enters the first reactor, wherein the gas phase component is discharged upward from the first reactor, and the liquid phase component is subjected to hydrogenation reaction downward, and the first reactor effluent is discharged from the bottom of the first reactor;

[0009] (3) the gas phase components are discharged from the first reactor and enter the second reactor to undergo a hydrodesulfurization reaction to obtain an effluent from the second reactor;

[0010] (4) The effluent from the first reactor and the effluent from the second reactor are stripped to obtain a jet fuel product.

[0011] Furthermore, the aviation kerosene raw material is a high dry point aviation kerosene raw material with the following properties: initial distillation point of 120°C to 150°C, final distillation point of 280°C to 300°C, sulfur content ≯3000μg / g, further 500 to 3000μg / g, smoke point ≮10mm, further 15 to 22mm.

[0012] Furthermore, the gasification conditions in the mixing container are as follows: pressure of 0.01-5.0 MPa, preferably 0.1-2.0 MPa; hydrogen-oil volume ratio of 1-600, preferably 50-400; temperature of 150-400°C, preferably 220-280°C.

[0013] Furthermore, the mixing container can be a conventional fixed bed reactor, with inlets for the crude oil and hydrogen, and an outlet for the gas phase mixture. The mixing container is filled with fillers or internal components having a fluid flow distribution function, preferably inert fillers such as porcelain balls or Raschig rings.

[0014] Furthermore, the first reactor and the second reactor are both fixed bed reactors, and the first reactor is preferably a fixed bed reactor provided with a flash zone.

[0015] Furthermore, a flash zone is provided in the first reactor, no catalyst is loaded in and above the flash zone, and a reaction zone is provided below the flash zone. The gas mixture is pressurized and fed into the flash zone of the first reactor, the obtained gas phase components are discharged upward from the first reactor, the obtained liquid phase components are subjected to hydrogenation reaction downward, and the obtained first reactor effluent is discharged from the bottom of the first reactor.

[0016] Furthermore, the operating conditions of the first reactor are as follows: pressure of 1.0-8.0 MPa, preferably 2.0-5.0 MPa; temperature of 80-280°C, preferably 120-220°C; volume space velocity of 0.1-4.0 h -1 , preferably 0.5~2.0h -1 .

[0017] Furthermore, the pressure in the first reactor is at least 0.5 MPa higher than the pressure in the mixing container, preferably 0.5-4.0 MPa higher, and more preferably 0.5-3.0 MPa higher.

[0018] Further, the first reactor is loaded with a hydrodearomatization catalyst. The hydrodearomatization catalyst can be a non-precious metal catalyst, including a hydrogenation active metal and a carrier, the carrier can be an alumina-based carrier, the hydrogenation active metal includes a VIB and / or VIII group metal component, wherein the VIB group is selected from tungsten and / or molybdenum, and the VIII group is selected from nickel and / or cobalt. The hydrodearomatization catalyst is preferably a Mo-Ni type hydrogenation catalyst. Generally, based on the mass of the catalyst, the content of MoO3 is 10wt% to 20wt%, and the content of NiO is 1wt% to 9wt%. The hydrodearomatization catalyst can adopt a commercial hydrogenation catalyst, such as a light distillate oil hydrogenation catalyst developed by Sinopec Fushun Petrochemical Research Institute (FRIPP), such as FH-40A and FH-40D.

[0019] Furthermore, the gaseous components are discharged from the first reactor and enter the second reactor, and hydrogen is introduced into the second reactor at the same time according to actual conditions.

[0020] Furthermore, in the second reactor, the conditions of the hydrodesulfurization reaction are as follows: pressure of 0.1-3.0 MPa, preferably 0.5-2.0 MPa; temperature of 100-300°C, preferably 150-250°C; hydrogen-to-oil volume ratio of 1-350, preferably 200-300, volume space velocity of 0.1-4.0 h -1 , preferably 0.5~2.0h -1 .

[0021] Further, the second reactor is loaded with a hydrodesulfurization catalyst, the hydrodesulfurization catalyst comprises a hydrogenation active metal and a carrier, the hydrogenation active metal comprises a metal component of Group VIB and / or Group VIII, wherein Group VIB is selected from tungsten and / or molybdenum, and Group VIII is selected from nickel and / or cobalt. The hydrodesulfurization catalyst is preferably a Mo-Co type hydrogenation catalyst, generally, based on the mass of the catalyst, the content of MoO3 is 12wt% to 20wt%, and the content of CoO is 1.5wt% to 7wt%. The hydrodearomatization catalyst can be a commercial hydrogenation catalyst, such as a catalyst developed by Sinopec Fushun Research Institute of Petrochemicals (FRIPP), for example, FH-40B.

[0022] Furthermore, the effluent from the first reactor and the effluent from the second reactor are stripped to obtain aviation fuel products.

[0023] Furthermore, the properties of the jet fuel product are as follows: smoke point ≮25 mm, wear scar diameter ≯0.65 mm.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The present invention uses a phase change process in which hydrogen and crude oil are gasified and then liquefied to enhance hydrogen dissolution, which makes up for the poor dissolution effect of gaseous hydrogen and liquid raw material in the conventional liquid phase technology and the high cost of membrane hydrogen mixing equipment, thereby achieving low-cost hydrogen dissolution and enhancing the hydrogen mixing effect.

[0026] (2) The mixing container used in the present invention is more cost-effective than the hydrogen mixing equipment currently used in industry. When used in conjunction with the subsequent pressurizing equipment, it can greatly increase the amount of hydrogen dissolved. At the same time, the liquefied oil is also conducive to the dissolution of hydrogen, so that more hydrogen can be dissolved in the liquefied component to meet the hydrogen needs of the subsequent liquid phase hydrogenation device.

[0027] (3) The method of the present invention controls the liquefaction rate of the effluent of the mixing container through pressure conditions, and can separate small molecular sulfides and aromatics. Due to the high freezing point of the large molecular components, substances such as large molecular aromatics are liquefied first, while small molecular sulfides (thiols, thioethers) and other substances are difficult to liquefy and enriched in the unliquefied components, which can provide suitable feeds for the liquid phase hydrogenation reactor and the gas phase hydrogenation reactor respectively. For the gas phase hydrogenation reactor, only the mercaptan needs to be removed until it meets the standard, and some sulfides that are beneficial to the lubricity of aviation kerosene are retained, thereby reducing the severity of the reaction and hydrogen consumption. The entire reaction system does not require a hydrogen compressor in a fixed bed reaction system and a circulating oil pump in a liquid phase hydrogenation reaction system, which simplifies the process flow and reduces investment costs. At the same time, due to the different reaction characteristics of different substances, the environment and conditions for dearomatization and desulfurization reactions are set in a targeted manner, which greatly improves the reaction efficiency and reduces the severity of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the process flow of producing high smoke point aviation fuel according to the present invention;

[0029] Among them, 1-hydrogen and jet fuel raw materials, 2-mixing container, 3-gas mixture, 4-compressor, 5-first reactor, 6-gas components, 7-first reactor effluent, 8-second reactor, 9-second reactor effluent, 10-stripping tower, 11-jet fuel product. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with embodiments, but it should be understood that the protection scope of the present invention is not limited by the embodiments.

[0031] In the present invention, unless otherwise explicitly stated, percentages and contents are all based on mass.

[0032] In the present invention, the smoke point of aviation kerosene is measured by the GB / T 382 method, and the analyzing instrument is the SH382 aviation kerosene smoke point measuring instrument; the wear scar diameter is measured by the SH / T 0687 method, and the analyzing instrument is the ball-column lubricity assessing instrument.

[0033] Combine the following Figure 1 The process flow of the present invention is described in detail.

[0034] Hydrogen and jet fuel raw material 1 enter into a mixing container 2, are gasified and fully mixed to obtain a gas mixture 3; enter into a compressor 4, and after being pressurized by the compressor 4, enter into a first reactor 5, where the liquid component undergoes a hydrogenation reaction downward to obtain a first reactor effluent 7, and the gaseous component 6 is discharged upward from the first reactor to enter into a second reactor 8 for a gas-phase hydrogenation desulfurization reaction to obtain a second reactor reaction effluent 9, and enters into a stripping tower 10 together with the first reactor reaction effluent 8 to finally obtain a jet fuel product 11.

[0035] Examples 1-3

[0036] Use Figure 1 Schematic diagram of the process. Two 100mL fixed-bed hydrogenation reactors are connected in series, and a reciprocating compressor is set in front of the first reactor. The first reactor is a liquid phase hydrogenation reactor, loaded with 70mL Mo-Ni hydrogenation catalyst A, and the second reactor is a gas phase hydrogenation reactor, loaded with 30mL Mo-Co type light distillate oil hydrogenation catalyst B. A mixing container is set in front of the compressor, loaded with 50mL Raschig rings. A gas phase outlet is set above the first reactor, and the liquid phase outlet pipeline at the bottom of the first reactor is connected to the stripping tower, and enters the stripping tower behind together with the effluent from the second reactor outlet. The properties of the catalyst are shown in Table 1, the properties of the feed oil are shown in Table 2, and the reaction process conditions and results are shown in Table 3.

[0037] Comparative Example 1

[0038] A conventional single-stage 100 mL fixed bed hydrotreating process was used, the raw materials were the same as in Example 1, and 100 mL of catalyst A was loaded. The reaction process conditions and results are shown in Table 3.

[0039] Comparative Example 2

[0040] The jet fuel liquid phase hydrogenation process was adopted, a single-stage 100 mL fixed bed reactor was used, a high-efficiency hydrogen mixer was set before the reactor, and a conventional low-fraction and stripping device was set after the reactor. The raw materials were the same as those in Example 1, and 100 mL of catalyst A was loaded. The reaction process conditions and results are shown in Table 3.

[0041] Comparative Example 3

[0042] A two-stage hydrogenation process was adopted, and reactor 1 and reactor 2 were set up. The same raw materials as in Example 1 were introduced into reactor 2 (gas phase desulfurization, loaded with 30 mL of hydrogenation catalyst B) and reactor 1 (liquid phase dearomatization, loaded with 70 mL of hydrogenation catalyst A) in sequence. A stripping device was required between the two hydrogenation reactors.

[0043] Table 1 Physicochemical properties of catalysts

[0044] Catalyst No. A B Brand FH-40A FH-40B Active Metals Mo-Ni Co-Mo <![CDATA[MoO3,wt%]]> 15 15 NiO / CoO, wt% 4.5 4.0 shape Shamrock Shamrock Diameter, mm 1.8 2.0 <![CDATA[Specific surface area, m 2 ·g -1 > 200 220 <![CDATA[Pore volume, mL·g -1 > 0.45 0.45

[0045] Table 2 Raw oil properties

[0046] Oil properties Jet fuel <![CDATA[Density (20 °C), g·cm -3 > 0.82 Distillation range, ℃ 140～300 <![CDATA[S,μg·g -1 ]]> 1735 <![CDATA[N,μg·g -1 ]]> 24 Smoke point, mm 20

[0047] Table 3 Process conditions and results

[0048]

[0049]

[0050] As can be seen from Table 3, when using the operating conditions of a conventional fixed-bed hydrogenation reactor industrial device, the smoke point index cannot meet the requirements due to insufficient saturation of aromatics in the raw materials due to the pressure level limitation. However, the existing device cannot improve the saturation of aromatics to meet the smoke point requirements by increasing the reaction pressure due to its low design level. When using the jet fuel liquid phase hydrogenation technology to process high dry point raw materials, the smoke point index is difficult to meet the requirements due to the increase in aromatic content, and the cost is greatly increased due to the use of a high-efficiency hydrogen mixer for hydrogen dissolution.

[0051] Comparative Example 3 adopts a two-stage hydrogenation technology. After the first stage of hydrogenation, steam stripping is required to remove hydrogen sulfide, and then the whole fraction enters the second stage hydrogenation reactor. Since desulfurization and dearomatization reactions occur simultaneously in the two reactors, while the smoke point index is qualified, the sulfide is removed to too low a level, affecting the ink mark diameter (lubricity) index (≯0.65 mm is qualified).

[0052] The present invention greatly improves the solubility of hydrogen through the phase change process of the raw material and hydrogen by arranging a gas phase mixer before the liquid phase hydrogenation reactor, meets the hydrogen demand of the liquid phase hydrogenation reaction, and separates materials with different properties by controlling the liquefaction rate of the effluent of the hydrogen mixing container. According to the different reaction types of different substances in the raw materials, different reaction conditions are provided in a targeted manner, so that the two reactors of liquid phase hydrogenation and gas phase hydrogenation are organically combined, which greatly promotes the saturation reaction of aromatics and other substances that affect the smoke point properties of aviation kerosene, thereby improving the smoke point of refined aviation kerosene; moreover, while achieving deep dearomatization, it also retains some sulfides that are beneficial to the lubricity of aviation kerosene, is beneficial to the ink mark diameter index, and reduces the reaction hydrogen consumption. The entire reaction system does not require a hydrogen compressor in a fixed bed reaction system and a circulating oil pump in a liquid phase hydrogenation reaction system, simplifies the process flow, reduces investment costs, and not only improves the reaction efficiency but also reduces the severity of the reaction.

Claims

1. A method for producing aviation fuel, characterized in that: The method comprises the following steps: (1) The jet fuel raw material and hydrogen enter a mixing container and are gasified to obtain a gas phase mixture; (2) The gas phase mixture is pressurized and enters the first reactor, wherein the gas phase component is discharged upward from the first reactor, and the liquid phase component is subjected to hydrogenation reaction downward, and the obtained first reactor effluent is discharged from the bottom of the first reactor; (3) the gas phase components are discharged from the first reactor and enter the second reactor to undergo a hydrodesulfurization reaction to obtain an effluent from the second reactor; (4) stripping the effluent from the first reactor and the effluent from the second reactor to obtain a jet fuel product; The gasification conditions in the mixing container are as follows: pressure of 0.01-5.0 MPa, hydrogen-to-oil volume ratio of 1-600, and temperature of 150-400°C; The operating conditions of the first reactor are as follows: pressure of 1.0-8.0 MPa, temperature of 80-280°C, volume space velocity of 0.1-4.0 h -1 ; In the second reactor, the conditions of the hydrodesulfurization reaction are as follows: pressure 0.1-3.0 MPa, temperature 100-300°C, hydrogen-to-oil volume ratio 1-350, volume space velocity 0.1-4.0 h -1 .

2. The method according to claim 1, characterized in that The properties of the aviation kerosene raw material are as follows: initial distillation point is 120°C to 150°C, final distillation point is 280°C to 300°C, sulfur content ≯3000μg / g, and smoke point ≮10mm.

3. The method according to claim 2, characterized in that The properties of the aviation kerosene raw material are as follows: sulfur content is 500-3000 μg / g, and smoke point is 15-22 mm.

4. The method according to claim 1, characterized in that The gasification conditions in the mixing container are as follows: pressure of 0.1-2.0 MPa; hydrogen-oil volume ratio of 50-400; temperature of 220-280°C.

5. The method according to claim 1, characterized in that The mixing container is a fixed bed reactor, and the mixing container is filled with fillers or internal components having a fluid flow distribution function.

6. The method according to claim 5, characterized in that The mixing container is filled with porcelain balls or Raschig rings.

7. The method according to claim 1, characterized in that The first reactor and the second reactor are both fixed bed reactors, and the first reactor is a fixed bed reactor provided with a flash zone.

8. The method according to claim 1, characterized in that The operating conditions of the first reactor are as follows: pressure of 2.0-5.0 MPa; temperature of 120-220°C; volume space velocity of 0.5-2.0 h -1 .

9. The method according to claim 8, characterized in that The pressure in the first reactor is at least 0.5 MPa higher than the pressure in the mixing vessel.

10. The method according to claim 9, characterized in that The pressure of the first reactor is 0.5-4.0 MPa higher than the pressure in the mixing container.

11. The method according to claim 9, characterized in that The pressure of the first reactor is 0.5-3.0 MPa higher than the pressure in the mixing container.

12. The method according to claim 1, characterized in that In the second reactor, the conditions of the hydrodesulfurization reaction are as follows: pressure of 0.5-2.0 MPa; temperature of 150-250°C; hydrogen-to-oil volume ratio of 200-300; volume space velocity of 0.5-2.0 h -1 .

13. The method according to claim 1, characterized in that The first reactor is filled with a hydrodearomatization catalyst, and the second reactor is filled with a hydrodesulfurization catalyst.

14. The method according to claim 1, characterized in that The properties of the jet fuel product are as follows: smoke point ≮25mm, wear scar diameter ≯0.65mm.

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