System and method for producing biological aviation kerosene by using waste oil

Abstract

The invention discloses a system and a method for producing biological aviation kerosene by using waste oil and belongs to the technical field of biological aviation kerosene preparation. The method comprises the following steps: (1) the waste grease and a magnetic catalyst loaded with ionic liquid are mixed and enter a suspended bed pre-hydrogenation reactor for reaction to obtain a pre-hydrogenation product, a carrier in the magnetic catalyst loaded with the ionic liquid is Fe3O4 magnetic particles coated with a silicon dioxide layer, and the ionic liquid is molybdenum-based ionic liquid; (2) separating the pre-hydrogenation product to obtain a primary hydrogenation product; (3) performing hydrogenation upgrading on the primary hydrogenation product to obtain an upgraded intermediate product; (4) separating the upgrading intermediate product to obtain a secondary hydrogenation upgrading product; and (5) carrying out hydroisomerization reaction on the secondary hydrogenation upgrading product to obtain the biological aviation kerosene. According to the method, the magnetic catalyst loaded with the ionic liquid is adopted to catalyze the waste grease, recycling can be achieved under the action of a magnetic field, the catalytic stability is high, and industrial stable production can be achieved without supplementing the catalyst.

Description

Technical Field

[0001] The present application relates to a system and method for producing bio-jet fuel using waste oil and fat, and belongs to the technical field of bio-jet fuel preparation. Background Art

[0002] Biojet fuel is a type of jet fuel produced from renewable resources. It comes from a wide range of sources, including vegetable oils (such as palm oil, rapeseed oil, and jatropha oil), animal fats (such as tallow and lard), waste cooking oil, acidified oil, and algae oil. These renewable raw materials can reduce reliance on traditional fossil fuels.

[0003] As global attention to environmental protection and sustainable development continues to grow, biojet fuel, as a green aviation fuel, holds broad development prospects. Biojet fuel can reduce carbon emissions by over 50% over its entire lifecycle, making it a core path for the aviation industry's green and low-carbon transformation. In the future, with continued technological advancements and reduced production costs, biojet fuel is expected to gain wider application in the aviation sector, gradually replacing some traditional jet fuel and making a significant contribution to achieving low-carbon development in the aviation industry.

[0004] Waste oils and fats mainly include waste cooking oils and animal fats. Their main components are glycerides and free fatty acids, which are composed of three elements: carbon, hydrogen, and oxygen. These waste oils and fats are widely available, and their use in the production of bio-jet fuel will have great social value. However, waste oils and fats have the disadvantages of high acid value and excessive content of metal elements such as Fe, Na, and Ca, as well as elements such as O, N, and P. On the one hand, fixed-bed catalysts are easily poisoned and deactivated, and coking and clogging make long-term operation difficult. On the other hand, the carrier of the supported catalyst has a direct impact on the service life and stability of the catalyst. Therefore, the use of liquid catalysts can greatly solve the above problems. However, liquid catalysts also have disadvantages such as difficulty in separation and recovery, insufficient stability, easy deactivation, single function, and weak resistance to impurities, which limit the industrial promotion of bio-jet fuel.

[0005] For example, patent CN116376595A uses a liquid catalyst containing molybdenum to mix with liquid waste oil and fat, and obtains renewable aviation fuel through pre-hydrogenation, hydrogenation, and hydroisomerization. However, the liquid catalyst has the disadvantages of being difficult to recover and having weak resistance to impurities. In industrial production, catalyst needs to be added in each batch to achieve the same effect. If the catalyst is not added, the stability of industrial production is poor, making it difficult to maintain efficient production.

[0006] Therefore, there is an urgent need for a method for producing bio-jet fuel from waste oil that is simple to recycle, highly stable, and can achieve industrial and stable production without the addition of catalysts, so as to improve the practicality and sustainability of the technology for producing bio-jet fuel from waste oil. Summary of the Invention

[0007] In order to solve the above problems, the present application proposes a system and method for producing bio-jet fuel using waste oil. The method uses a magnetic catalyst loaded with ionic liquid to catalyze the waste oil. Since the catalyst is a combination of a liquid catalyst and a solid catalyst, it has both the high efficiency of a liquid catalyst and the easy recovery of a solid catalyst. In the production of bio-jet fuel, it can efficiently catalyze the raw materials, improve the raw material utilization rate and product yield. Moreover, since it is magnetic, it can be recovered under the action of a magnetic field, thereby improving the catalytic efficiency and stability of the catalyst, and can achieve industrial and stable production without the need to add catalyst.

[0008] According to one aspect of the present application, a method for producing bio-jet fuel using waste oil and fat is provided, comprising the following steps:

[0009] (1) Pre-treating the waste oil in a pre-treatment device, and then mixing it with a magnetic catalyst loaded with an ionic liquid and entering into a suspended bed pre-hydrogenation reactor for a pre-hydrogenation reaction to obtain a pre-hydrogenated product. After the pre-hydrogenation reaction is completed, the magnetic catalyst loaded with an ionic liquid is fixed in the suspended bed pre-hydrogenation reactor under a magnetic field and used for a long period of time, wherein the carrier of the magnetic catalyst loaded with an ionic liquid is Fe3O4 magnetic particles coated with a silicon dioxide layer, and the ionic liquid is a platinum-based ionic liquid;

[0010] (2) performing gas-liquid separation and non-hydrogenation post-treatment separation on the pre-hydrogenation product to obtain a primary hydrogenation product;

[0011] (3) The primary hydrogenation product enters a hydrogenation upgrading reactor containing a solid catalyst to obtain an upgraded intermediate product;

[0012] (4) The upgraded intermediate product enters the hydrogen stripping tower to separate the gaseous product to obtain the secondary hydrogenation upgraded product;

[0013] (5) The secondary hydrogenation upgrading product enters the hydroisomerization reactor, reacts under the catalysis of a reduced catalyst, and is fractionated to obtain bio-jet fuel.

[0014] In step (1), a magnetic catalyst loaded with an ionic liquid is used to pre-hydrogenate waste grease in a suspended bed reactor. Due to the presence of the suspended bed reactor, the contact effect between the magnetic catalyst loaded with the ionic liquid and the waste grease is good, thereby improving the catalytic efficiency of the waste grease and the yield of the pre-hydrogenated product. The magnetic catalyst loaded with an ionic liquid used in this step (1) uses Fe3O4 magnetic particles as the core and can be recovered under the action of a magnetic field. The silicon dioxide layer serves as a protective layer for the Fe3O4 magnetic particles. First, it can prevent the agglomeration of the Fe3O4 magnetic particles, so that the magnetic catalyst has better dispersibility and stability, which is conducive to giving full play to the role of active sites in the catalytic reaction and improving the catalytic efficiency of the magnetic catalyst. Second, the Fe3O4 magnetic particles can be isolated from the external environment to prevent the magnetic core from being oxidized, corroded or chemically reacting with other substances, thereby maintaining the magnetic properties and structural stability of the magnetic particles and extending the service life of the magnetic catalyst. Third, the presence of the silicon dioxide protective layer does not affect the effect of magnetic separation, and can also prevent the Fe3O4 magnetic particles from adhering to or agglomerating with other substances during the separation process, thereby improving the recovery rate and catalytic effectiveness of the magnetic catalyst in this application.

[0015] The pre-hydrogenation product obtained through the step (1) reaction has low impurity content and significantly reduced acid value, thereby improving the yield of subsequent primary hydrogenation products, secondary hydrogenation upgrading products and bio-jet fuel.

[0016] Optionally, the preparation method of the ionic liquid-loaded magnetic catalyst is:

[0017] S1: Disperse the structure-directing agent hexadecyltrimethylammonium bromide in a solvent, add Fe3O4 magnetic particles, sonicate for a certain period of time, add deionized water, add tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane under vigorous stirring, react for a certain period of time, separate and collect the product using an external magnet, and wash to obtain intermediate A;

[0018] S2: adding the intermediate A to a solution containing an epoxyalkane compound, stirring and reacting at 70-80° C. for at least 16 hours, separating and collecting the product using an external magnet, and washing to obtain the support;

[0019] S3: adding the carrier to a solution containing molybdic acid, stirring for reaction, separating and collecting the product by an external magnet, and washing to obtain the magnetic catalyst loaded with the ionic liquid.

[0020] The magnetic catalyst loaded with ionic liquid prepared by the above steps, in step S1, tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane form a silica protective layer on the outside of Fe3O4 magnetic particles, this step can improve the coating effect of Fe3O4 magnetic particles, and can also introduce tert-butylpropylamino groups on the outside of the silica protective layer, the -NH of this group acts as a reactive group to react with the epoxy alkane compound in step S2 to form a tertiary amine and a long-chain alkyl group, the tertiary amine can react with molybdic acid in step S3 to form a molybdenum-based ionic liquid, giving the magnetic catalyst excellent catalytic performance, and the long-chain alkyl group can improve the molybdenum The compatibility of the ionic liquid with waste grease enables the magnetic catalyst loaded with the ionic liquid to be better mixed with the waste grease and evenly dispersed in the reaction system, thereby increasing the contact area between the magnetic catalyst loaded with the ionic liquid and the waste grease and improving the catalytic efficiency; and the tert-butyl group adjacent to the -NH in the group can be large in size, forming a steric hindrance around the active center of the catalyst, making it difficult for some large impurity molecules to approach the metal active center, thereby reducing the contact opportunity between the impurities and the active center, reducing the poisoning effect of impurities on the active center of the magnetic catalyst, and enhancing the anti-impurity ability of the magnetic catalyst. However, the presence of the tert-butyl group causes the reaction efficiency of -NH with the epoxy alkane compound in step S2 to decrease, so the required reaction temperature is higher and the reaction time is longer.

[0021] Optionally, the particle size of the Fe3O4 magnetic particles is 200-500 nm.

[0022] Optionally, in step S1, the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate is 1:(6-8);

[0023] The weight ratio of Fe3O4 magnetic particles to structure-directing agent hexadecyltrimethylammonium bromide is 1:(0.5-1).

[0024] Optionally, in step S1, the weight ratio of Fe3O4 magnetic particles to tert-butylpropylaminotrimethoxysilane is 1:(2-3).

[0025] The above-mentioned amount can not only increase the number of tert-butylpropylamino groups on the surface of Fe3O4 magnetic particles, but also improve the dispersibility of this group on the surface of Fe3O4 magnetic particles, which is convenient for the reactions in subsequent steps S2 and S3. If the amount of tert-butylpropylaminotrimethoxysilane is too small, the catalytic active sites of the prepared magnetic catalyst loaded with ionic liquid will decrease, resulting in a decrease in catalytic efficiency. However, if the amount of tert-butylpropylaminotrimethoxysilane is too large, it will affect the density of the silica coating layer in the magnetic catalyst loaded with ionic liquid, resulting in a decrease in the magnetic stability of the magnetic catalyst and a shortened service life. At the same time, due to the large number of tert-butyl groups carried on the magnetic catalyst, the steric effect will increase, resulting in a slight decrease in catalytic efficiency.

[0026] Optionally, the epoxyalkane in step S2 is selected from at least one of 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, and 1,2-epoxytetradecane.

[0027] The epoxyalkane reacts with intermediate A to obtain a carrier. The epoxyalkane contains epoxy groups that participate in the reaction, and the remaining long-chain alkanes can increase the compatibility with waste oils and fats, thereby improving the catalytic efficiency of the magnetic catalyst for waste oils and fats and increasing the yield of each level of product. However, if the long-chain alkanes are too long, they will cover the active sites, reducing the catalytic activity of the supported ionic liquid catalyst, and also reduce the thermal stability of the magnetic catalyst, thereby shortening the service life of the magnetic catalyst.

[0028] Optionally, in step S2, the weight ratio of intermediate A to epoxyalkane is 1:(1-1.5).

[0029] The above dosage can increase the yield of the carrier obtained by the reaction of the intermediate A and the epoxyalkane, improve production efficiency, and save production costs.

[0030] Optionally, in step S3, the weight ratio of the carrier to molybdic acid is 1:(0.8-1.2);

[0031] In step S3, after the carrier is added to the solution containing molybdic acid, the reaction is stirred at 20-30° C. for 5-6 hours, and then stirred at 50-60° C. for 12-15 hours.

[0032] The dosage and reaction conditions can increase the formation of molybdenum-containing ionic liquid, thereby increasing the number of active sites of the magnetic catalyst and achieving efficient catalysis at low dosage.

[0033] Optionally, the amount of the ionic liquid-loaded magnetic catalyst added in step (1) is 300 to 1000 ppm;

[0034] The hourly space velocity of the reaction liquid in step (3) is 0.2 to 3.0 h -1 ;

[0035] The reaction liquid hourly space velocity in step (5) is 0.2~3.0h -1 .

[0036] Optionally, the solid catalyst in step (3) is selected from at least one of Mo-Ni loaded γ-alumina catalyst, Co-Mo loaded γ-alumina catalyst, and Ni-W loaded γ-alumina catalyst, and the reduced catalyst in step (5) is selected from at least one of nickel loaded molecular sieve catalysts Ni / ZSM-22, Ni / ZSM-22 / Y, and Ni / ZSM-22 / ZSM-5.

[0037] Optionally, the pressure of the suspended bed pre-hydrogenation reactor in step (1) is 2 to 8 MPa and the temperature is 340 to 360° C.;

[0038] The pressure of the hydrogenation reactor in step (3) is 2-8 MPa and the temperature is 310-330°C;

[0039] The pressure of the hydroisomerization reactor in step (5) is 2-8 MPa and the temperature is 280-320°C.

[0040] The production method of the present application involves catalytically producing bio-jet fuel at medium-to-low pressure. The aforementioned temperatures and pressures can, firstly, reduce production energy consumption and save production costs; secondly, avoid coking, facilitating long-term industrial production. In particular, at the reaction pressure and temperature in step (1), the magnetic catalyst loaded with an ionic liquid can maintain stability, ensuring efficient catalysis while extending its service life.

[0041] According to another aspect of the present application, a system for producing bio-jet fuel from waste oil and fat is provided, characterized in that the system is used to implement any of the above-mentioned methods for producing bio-jet fuel from waste oil and fat, comprising:

[0042] A raw material storage tank, wherein the raw material storage tank is used to store waste oil;

[0043] A pre-processor, which is used to remove impurities from waste grease;

[0044] A suspended bed pre-hydrogenation reactor, wherein the inlet of the suspended bed pre-hydrogenation reactor is connected to the pre-treatment device, the suspended bed pre-hydrogenation reactor is further provided with a magnetic field component, the magnetic field component is energized to form a magnetic field in the suspended bed pre-hydrogenation reactor, and the outlet of the suspended bed pre-hydrogenation reactor is sequentially connected to a gas-liquid separator and a non-hydrogenation treatment device;

[0045] a hydro-upgrading reactor, wherein the inlet of the hydro-upgrading reactor is connected to the non-hydrogenation processor, and the outlet is connected to the hydro-stripping tower;

[0046] The hydroisomerization reactor has an inlet connected to a hydrogen stripping tower, and an outlet connected to a fractionator, and the outlet of the fractionator distills out bio-jet fuel.

[0047] The beneficial effects of this application include but are not limited to:

[0048] 1. The method for producing bio-jet fuel from waste oil provided in this application uses an ionic liquid-loaded magnetic catalyst that combines the advantages of both liquid and solid catalysts. It can not only take advantage of the efficient conversion of ionic liquid liquid catalysts in pre-hydrogenation reactions, avoiding the disadvantage of liquid catalysts that cannot be recovered and need to be continuously replenished in homogeneous reactions, but also take advantage of the recyclability of solid catalysts, avoiding the disadvantage of solid catalysts that are easily coked and deactivated, resulting in low catalytic efficiency.

[0049] 2. The method provided in this application for producing bio-jet fuel from waste oil uses Fe3O4 magnetic particles as the core of the magnetic catalyst loaded with ionic liquid. The catalyst can be recovered under the action of a magnetic field. After 100 days of reaction, the catalyst recovery rate is over 80%, which can meet the needs of long-term industrial production.

[0050] 3. The method for producing bio-jet fuel from waste oil provided in this application is that the magnetic catalyst loaded with ionic liquid is not only recyclable, but also has a strong ability to resist impurities and high catalytic stability for waste oils of different properties. The recovered catalyst can be reused for efficient catalysis of waste oils, laying the foundation for the industrial production of bio-jet fuel from waste oils.

[0051] 4. In the method for producing bio-jet fuel using waste oil provided in the present application, after the production in step (1) is completed, a magnetic field component is used to fix the magnetic catalyst loaded with ionic liquid in the reactor, so that the magnetic catalyst can be recovered. Therefore, industrial long-term production can be achieved without the need for additional magnetic catalyst loaded with ionic liquid, and the product obtained by long-term production has good quality uniformity and is suitable for large-scale promotion and use.

[0052] 5. In the method provided in this application for producing bio-jet fuel using waste oil, the molybdenum-based ionic liquid forms a chemical bond with the silica layer of the magnetic carrier shell. Therefore, the molybdenum-based ionic liquid has high stability on the overall magnetic catalyst, can function sustainably and efficiently, and improves the service life of the magnetic catalyst loaded with the ionic liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0054] Figure 1 This is a schematic structural diagram of a system for producing bio-jet fuel using waste oils and fats according to Example 1 of the present application;

[0055] List of parts and reference numerals:

[0056] 10. Raw material storage tank; 20. Pre-treatment unit; 30. Suspended bed pre-hydrogenation reactor; 40. Gas-liquid separator; 50. Non-hydrogenation treatment unit; 60. Hydrogenation upgrading reactor; 70. Hydrogenation stripping tower; 80. Hydroisomerization reactor; 90. Fractionator. DETAILED DESCRIPTION

[0057] In order to more clearly illustrate the overall concept of the present application, a detailed description is given below in an illustrative manner in conjunction with the accompanying drawings.

[0058] In order to more clearly understand the above-mentioned objects, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other in the absence of conflict.

[0059] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0060] In addition, in the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0062] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0063] In this application, unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0064] Unless otherwise specified, the raw materials in the examples of this application were purchased from commercial channels. Waste oil refers to at least one of acidified oil, waste cooking oil, and animal fat. The specific type of solvent is not specified in the following Example 2. As long as the solvent used can ensure the dissolution of the raw materials and the occurrence of the reaction, the specific type of solvent does not constitute a limitation of this application. Those skilled in the art can select according to actual needs. In addition, in Example 2, the intermediate A, the carrier, and the magnetic catalyst are first cleaned with a solvent and then with deionized water.

[0065] Unless otherwise specified, the methods used in the embodiments of the present application are conventional methods in the prior art.

[0066] Example 1

[0067] refer to Figure 1 This embodiment discloses a system for producing bio-jet fuel using waste oil, which includes:

[0068] Raw material storage tank 10, which is used to store waste oil;

[0069] The pre-processor 20 is used to remove impurities from the waste oil;

[0070] A suspended bed pre-hydrogenation reactor 30, wherein the inlet of the suspended bed pre-hydrogenation reactor 30 is connected to the pre-processor 20, and a magnetic field component is further provided in the suspended bed pre-hydrogenation reactor 30. The magnetic field component is energized to form a magnetic field in the suspended bed pre-hydrogenation reactor 30, and the outlet of the suspended bed pre-hydrogenation reactor 30 is sequentially connected to a gas-liquid separator 40 and a non-hydrogenation processor 50;

[0071] A hydro-upgrading reactor 60, wherein the inlet of the hydro-upgrading reactor 60 is connected to the non-hydrogenation processor 50, and the outlet is connected to the hydro-stripping tower 70;

[0072] The hydroisomerization reactor 80 has an inlet connected to the hydrogen stripping tower 70 and an outlet connected to the fractionator 90. The outlet of the fractionator 90 distills out the bio-jet fuel.

[0073] In this system, waste oil passes through the raw material storage tank 10 and is removed by the pre-processor 20 before entering the suspended bed pre-hydrogenation reactor 30. During initial production, the magnetic catalyst loaded with ionic liquid can be added to the waste oil in the suspended bed pre-hydrogenation reactor 30. During subsequent industrial long-term production, after each batch of waste oil is reacted in the suspended bed pre-hydrogenation reactor 30, the magnetic field component is energized to form a magnetic field in the suspended bed pre-hydrogenation reactor 30, and the magnetic catalyst loaded with ionic liquid is fixed in the suspended bed pre-hydrogenation reactor 30. The product is discharged from the outlet of the suspended bed pre-hydrogenation reactor 30 and is separated by the gas-liquid separator 40 and the non-hydrogenation processor 50 to obtain a primary hydrogenation product. The primary hydrogenation product then enters the hydro-upgrading reactor 60 for hydro-upgrading to obtain an upgraded intermediate product, and then passes through the hydro-stripping tower 70 to separate the gaseous product to obtain a secondary hydro-upgrading product. The secondary hydro-upgrading product then enters the hydro-isomerization reactor for hydro-isomerization, and the bio-jet fuel is obtained after fractionation.

[0074] The magnetic field component provided in the suspended bed pre-hydrogenation reactor 30 may be a coil, which is energized to generate a magnetic field to recover the magnetic catalyst of the present application, thereby enabling the magnetic catalyst of the present application to be reused. This configuration can be improved with reference to the magnetically stabilized bed reactor, or a coil magnetic field component can be directly added to the existing suspended bed pre-hydrogenation reactor 30. As long as the magnetic catalyst can be fixedly recovered after the reaction in the suspended bed pre-hydrogenation reactor 30 is completed, the specific configuration does not constitute a limitation on the present application.

[0075] When the waste oil production is carried out in a continuous production, the suspended bed pre-hydrogenation reactor 30 can be set as a continuous production reactor. At this time, the magnetic field component of the suspended bed pre-hydrogenation reactor 30 needs to be continuously energized during the pre-hydrogenation reaction to achieve the suspension fixation and recovery of the magnetic catalyst. The suspended bed pre-hydrogenation reactor 30 can also be set as a separate intermittent reactor. At this time, a buffer storage tank needs to be set before the suspended bed pre-hydrogenation reactor 30 and the gas-liquid separator 40. After each batch of products is reacted in the suspended bed pre-hydrogenation reactor 30, it will be discharged into the buffer storage tank for subsequent continuous production. At this time, the magnetic field component can be in an energized state or a non-energized state during the pre-hydrogenation reaction.

[0076] During the pre-hydrogenation reaction, if the magnetic field component is in an energized state, the magnetic catalyst is in a suspended and fixed state during the reaction, and catalytic hydrogenation is achieved by the contact between the waste oil and the suspended and fixed magnetic catalyst; if the magnetic field component is in a non-energized state, the magnetic catalyst and the waste oil are in a homogeneous mixed state, and after the reaction is completed, the magnetic catalyst is recovered by energizing the magnetic field component.

[0077] The above system can realize the industrial long-term production of bio-jet fuel from waste oil and fat, which is convenient for industrial promotion and use.

[0078] Example 2

[0079] This embodiment relates to the preparation of a magnetic catalyst loaded with an ionic liquid, and the specific method is as follows:

[0080] S1: dispersing a structure-directing agent, hexadecyltrimethylammonium bromide, in a solvent, adding Fe3O4 magnetic particles with a particle size of 200-500 nm, and adding deionized water after ultrasonication for a certain period of time. Tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane are added under vigorous stirring. After a certain period of reaction, the product is separated and collected by an external magnet, and washed to obtain an intermediate A, wherein the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate, structure-directing agent, hexadecyltrimethylammonium bromide, and tert-butylpropylaminotrimethoxysilane is 1:(6-8):(0.5-1):(2-3);

[0081] S2: adding the intermediate A to a solution containing an epoxyalkane compound, wherein the weight ratio of the intermediate A to the epoxyalkane is 1:(1-1.5), stirring and reacting at 70-80° C. for at least 16 hours, separating and collecting the product using an external magnet, and washing to obtain the carrier;

[0082] S3: Add the carrier to a solution containing molybdic acid, with a weight ratio of the carrier to molybdic acid of 1:(0.8-1.2), first stir and react at 20-30°C for 5-6 hours, then stir and react at 50-60°C for 12-15 hours, and then separate and collect the product by an external magnet, and wash to obtain the magnetic catalyst loaded with ionic liquid.

[0083] Optionally, the epoxyalkane in step S2 is selected from at least one of 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, and 1,2-epoxytetradecane.

[0084] Optionally, the ultrasonication time in step S1 is 10 to 15 minutes, and the reaction time is 4 to 6 hours.

[0085] Magnetic catalysts 1# to D3# were prepared according to the above preparation method, specifically as follows:

[0086] Magnetic Catalyst 1#

[0087] S1: Disperse the structure-directing agent hexadecyltrimethylammonium bromide in a solvent, add Fe3O4 magnetic particles with a particle size of 200 nm, sonicate for 15 minutes, add deionized water, add tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane under vigorous stirring, react for 4 hours, separate and collect the product using an external magnet, and wash to obtain intermediate A, wherein the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate, structure-directing agent hexadecyltrimethylammonium bromide, and tert-butylpropylaminotrimethoxysilane is 1:6:0.5:3;

[0088] S2: adding the intermediate A to a solution of 1,2-epoxydecane, with a weight ratio of the intermediate A to 1,2-epoxydecane being 1:1, stirring and reacting at 70° C. for 16 h, separating and collecting the product using an external magnet, and washing to obtain the carrier;

[0089] S3: The carrier is added to an ammonia solution containing molybdic acid (ammonia concentration is 15%, molybdic acid concentration is 0.1 mol / L), the weight ratio of the carrier to molybdic acid is 1:0.8, and the reaction is stirred at 20°C for 5 hours, then stirred at 50°C for 15 hours, and then the product is separated and collected by an external magnet, and washed to obtain the magnetic catalyst loaded with ionic liquid.

[0090] Magnetic Catalyst 2#

[0091] S1: Disperse the structure-directing agent hexadecyltrimethylammonium bromide in a solvent, add Fe3O4 magnetic particles with a particle size of 500 nm, sonicate for 10 minutes, add deionized water, add tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane under vigorous stirring, react for 6 hours, separate and collect the product using an external magnet, and wash to obtain intermediate A, wherein the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate, structure-directing agent hexadecyltrimethylammonium bromide, and tert-butylpropylaminotrimethoxysilane is 1:8:1:2;

[0092] S2: adding the intermediate A to a solution of 1,2-epoxytetradecane, with a weight ratio of the intermediate A to 1,2-epoxytetradecane of 1:1.5, stirring and reacting at 80° C. for 20 h, separating and collecting the product using an external magnet, and washing to obtain the carrier;

[0093] S3: The carrier is added to an ammonia solution containing molybdic acid (ammonia concentration is 15%, molybdic acid concentration is 0.1 mol / L), the weight ratio of the carrier to molybdic acid is 1:1.2, and the reaction is stirred at 30°C for 6 hours, then stirred at 60°C for 12 hours, and then the product is separated and collected by an external magnet, and washed to obtain the magnetic catalyst loaded with ionic liquid.

[0094] Magnetic Catalyst 3#

[0095] The difference between this magnetic catalyst and magnetic catalyst 1# is that the weight ratio of Fe3O4 magnetic particles to tert-butylpropylaminotrimethoxysilane in step S1 is 1:4, and the rest is the same as magnetic catalyst 1#.

[0096] Magnetic Catalyst 4#

[0097] The difference between this magnetic catalyst and magnetic catalyst 1# is that 1,2-epoxypentane is used instead of 1,2-epoxytetradecane in step S2, and the rest is the same as magnetic catalyst 1#.

[0098] Magnetic Catalyst 5#

[0099] The difference between this magnetic catalyst and magnetic catalyst 1# is that 1,2-epoxyoctadecane is used instead of 1,2-epoxytetradecane in step S2, and the rest is the same as magnetic catalyst 1#.

[0100] Magnetic Catalyst 6#

[0101] The difference between this magnetic catalyst and magnetic catalyst 1# is that acetamidopropyltrimethoxysilane is used instead of tert-butylpropylaminotrimethoxysilane in step S1, and the rest is the same as magnetic catalyst 1#.

[0102] Magnetic Catalyst 7#

[0103] The difference between this magnetic catalyst and magnetic catalyst 1# is that 3-aminopropyltrimethoxysilane is used instead of tert-butylpropylaminotrimethoxysilane in step S1, and the rest is the same as magnetic catalyst 1#.

[0104] Magnetic Catalyst 8#

[0105] S1: Disperse the structure-directing agent hexadecyltrimethylammonium bromide in a solvent, add Fe3O4 magnetic particles with a particle size of 500 nm, sonicate for 10 minutes, add deionized water, add tetraethyl orthosilicate under vigorous stirring, react for 6 hours, separate and collect the product using an external magnet, and wash to obtain intermediate A, wherein the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate and structure-directing agent hexadecyltrimethylammonium bromide is 1:8:1;

[0106] S2: Prepare trihexylmethylammonium molybdate catalyst according to the preparation method of Example 1 in CN112916041B;

[0107] S3: The intermediate is added to an ethanol-water solution of the trihexylmethylammonium molybdate catalyst prepared in step S2 (the concentration of the trihexylmethylammonium molybdate catalyst is 0.1 mol / L), stirred at 30°C for 6 hours, and then the product is separated and collected by an external magnet, and washed to obtain a magnetic catalyst loaded with an ionic liquid.

[0108] Comparison with magnetic catalyst D1#

[0109] The difference between this comparative magnetic catalyst and magnetic catalyst 1# is that in step S1, non-magnetic Fe2O3 particles of the same particle size are used to replace Fe3O4 magnetic particles, and the rest is the same as magnetic catalyst 1#.

[0110] Comparison with magnetic catalyst D2#

[0111] The difference between this comparative magnetic catalyst and magnetic catalyst 1# is that in step S3, the carrier is added to an aqueous solution containing nickel nitrate (the concentration of nickel nitrate is 0.1 mol / L), the weight ratio of the carrier to nickel nitrate is 1:1.2, and the rest is the same as magnetic catalyst 1#.

[0112] Comparison with magnetic catalyst D3#

[0113] The difference between this comparative magnetic catalyst and magnetic catalyst 1# is that in step S3, the carrier is added to an aqueous solution containing cobalt oxalate (the concentration of cobalt oxalate is 0.1 mol / L), the weight ratio of the carrier to cobalt oxalate is 1:1.2, and the rest is the same as magnetic catalyst 1#.

[0114] Example 3

[0115] This embodiment discloses a method for producing bio-jet fuel using waste oil and fat, which is carried out using the system of Example 1 and the ionic liquid-loaded magnetic catalyst of Example 2, and includes the following steps:

[0116] (1) Pre-treating waste oil and fat, and then mixing it with a magnetic catalyst loaded with an ionic liquid and introducing it into a suspended bed pre-hydrogenation reactor, performing a pre-hydrogenation reaction at a pressure of 2 to 8 MPa and a temperature of 340 to 360° C. to obtain a pre-hydrogenated product, wherein the amount of the magnetic catalyst loaded with the ionic liquid is 300 to 1000 ppm, and the hydrogen-to-oil volume ratio is 400 to 800. After the pre-hydrogenation reaction is completed, the magnetic catalyst loaded with the ionic liquid is fixed in the suspended bed pre-hydrogenation reactor under a magnetic field and used for a long period of time, wherein the carrier of the magnetic catalyst loaded with the ionic liquid is Fe3O4 magnetic particles coated with a silicon dioxide layer, and the ionic liquid is a platinum-based ionic liquid;

[0117] (2) performing gas-liquid separation and non-hydrogenation post-treatment separation on the pre-hydrogenation product to obtain a primary hydrogenation product;

[0118] (3) The primary hydrogenation product enters a hydrogenation upgrading reactor containing a solid catalyst, and reacts at a pressure of 2-8 MPa and a temperature of 310-330°C to obtain an upgraded intermediate product. The hourly space velocity of the reaction liquid is 0.2-3.0 h -1 , hydrogen-to-oil volume ratio 400-800;

[0119] (4) The upgraded intermediate product enters the hydrogen stripping tower to separate the gaseous product to obtain the secondary hydrogenation upgraded product;

[0120] (5) The secondary hydrogenation product enters the hydroisomerization reactor and reacts under the catalytic conditions of a reduced catalyst at a pressure of 2-8 MPa and a temperature of 280-320°C. Bio-jet fuel is obtained after fractionation. The reaction liquid has an hourly space velocity of 0.2-3.0 h -1 , hydrogen-to-oil volume ratio is 400-800.

[0121] According to the above process, the hydrogen-to-oil volume ratio in step (1) is 400, the solid catalyst in step (3) is a Mo-Ni supported γ-alumina catalyst, and the reaction liquid hourly space velocity is 3.0h -1 , hydrogen to oil volume ratio 800; step (5) the reduced catalyst is nickel supported molecular sieve catalyst Ni / ZSM-22 / Y, the reaction liquid hourly space velocity 3.0h -1 , hydrogen-to-oil volume ratio is 800; the remaining parameters are carried out according to the different production processes in the table below to prepare different primary hydrogenation products, secondary hydrogenation upgrading products and bio-jet fuel. The waste oil in the following process uses the same quality of waste cooking oil, and the system also adopts an intermittent production method.

[0122] Table 1

[0123]

[0124] Test Example 1

[0125] The primary hydrogenation product, secondary hydrogenation product, and bio-jet fuel obtained from Processes 1# to 12# in Example 3 were tested. The test results are shown in Tables 2 to 4 below. The density, freezing point of the bio-jet fuel product, total acid number (KOH), and total sulfur (mass fraction) in the following tests were all measured in accordance with GB6537-2018.

[0126] The test results are for the first batch of the method:

[0127] Table 2 Test results of primary hydrogenation products

[0128]

[0129] Table 3 Test results of secondary hydrogenation upgrading products

[0130]

[0131]

[0132] Table 4 Bio-jet fuel test results

[0133]

[0134] The total acid value (calculated as KOH) of the bio-jet fuel prepared in the above-mentioned processes 1# to 12# is greater than 0.015 mg / g, and the total sulfur (mass fraction) is not greater than 0.20%, which meets the requirements of GB6537-2018.

[0135] Test Example 2

[0136] The magnetic catalyst 1# used in process 1# was replaced with the liquid catalyst in Example 1 of CN112592730A as comparative process 1#, and the magnetic catalyst 1# used in process 1# was replaced with the liquid catalyst in Example 2 of CN112916041B as comparative process 2#. Processes 1# to 12# and comparative processes 1# and 2# in Example 3 were continuously operated for 100 days, and the change rates of the primary hydrogenation product, the secondary hydrogenation upgrading product, and the bio-jet fuel on the 50th and 100th days compared with those on the 1st day were detected to test the industrial long-term production capacity of the production method. The test results are shown in the table below. The definitions of the conversion rate change rate, the deoxygenation rate change rate, the isomerization rate change rate, the freezing point change rate of the bio-jet fuel product, and the catalyst recovery rate in Table 5 are as follows:

[0137] Conversion rate change rate: refers to the change in the "conversion rate" indicator in the test results of the first-stage hydrogenation product in Table 2, and is calculated as follows: conversion rate change rate = [(conversion rate on the first day - conversion rate on the nth day) / conversion rate on the first day] × 100%, where n is 50 or 100;

[0138] Deoxygenation rate change rate: refers to the change in the "deoxygenation rate" indicator in the test results of the secondary hydrogenation upgrading product in Table 3. The calculation formula is: Deoxygenation rate change rate = [(deoxygenation rate on the first day - deoxygenation rate on the nth day) / deoxygenation rate on the first day] × 100%, where n is 50 or 100;

[0139] Isomerization rate change rate: refers to the change in the "isomerization rate" indicator in the bio-jet fuel test results in Table 4. The calculation formula is: Isomerization rate change rate = [(isomerization rate on day 1 - isomerization rate on day n) / isomerization rate on day 1] × 100%, where n is 50 or 100;

[0140] Bio-jet fuel product freezing point change rate: refers to the change in the "bio-jet fuel product freezing point" indicator in the bio-jet fuel test results in Table 4, and is calculated as follows: Bio-jet fuel product freezing point change rate = [(bio-jet fuel product freezing point on day n - bio-jet fuel product freezing point on day 1) / bio-jet fuel product freezing point on day 1] × 100%, where n is 50 or 100;

[0141] Catalyst recovery rate: refers to the process after the end of the nth day of operation, in which the magnetic field component in the suspended bed pre-hydrogenation reactor is energized to fix the ionic liquid-loaded magnetic catalyst in the suspended bed pre-hydrogenation reactor. The fixed ionic liquid-loaded magnetic catalyst is recovered and its weight is measured. Catalyst recovery rate = (weight of catalyst on the nth day / weight of catalyst initially added on the first day) × 100%, where n is 50 or 100.

[0142] Table 5 The conversion rate change rate, deoxygenation rate change rate, isomerization rate change rate, bio-jet fuel product freezing point change rate and catalyst recovery rate of the system after 50 and 100 days of operation

[0143]

[0144]

[0145] During operation of the above processes, the suspended bed reactor employed intermittent production, with each production cycle of raw materials being called a batch. Since Process 10# employed non-magnetic particles, it relied solely on the inherent devices within the suspended bed reactor for interception during operation. Consequently, by the third batch, no significant catalytic effect was observed, making sustained operation difficult. Consequently, continuous operation to the 50th and 100th days was impossible, and the rate of change in the table above is not available and is indicated by a "-." Comparative Processes 1# and 2# employed liquid catalysts. Following the first batch of catalysis, the liquid catalyst was discharged into the system along with the impurities catalyzed by the waste oil. This made catalytic recovery more difficult than with Process 10#, and therefore continuous operation to the 50th and 100th days was impossible. The rate of change in the table above is not available and is also indicated by a "-."

[0146] The test results above demonstrate that the ionic liquid-loaded magnetic catalyst prepared in this application effectively catalyzes the decomposition of waste oils and fats, thereby improving the quality of primary hydrogenation products, secondary hydrogenation products, and bio-jet fuel. Furthermore, the presence of magnetic particles enables the recycling of the magnetic catalyst, allowing for continuous operation without the addition of additional magnetic catalyst. Even after 100 days of operation, the recovery rate of the magnetic catalyst remained above 80%.

[0147] A comparison of processes 1# and 2# shows that, under the action of the same magnetic catalyst, the amount of magnetic catalyst used and the reaction temperature will affect the test results of the primary hydrogenation product, the secondary hydrogenation quality-upgraded product, and the bio-jet fuel. A large amount of catalyst used and an increase in the reaction temperature and pressure will increase the conversion rate, deoxygenation rate, and isomerization rate. In particular, the isomerization rate is greatly affected by temperature, and the isomerization rate increases significantly at 320°C. This trend is the same as that in patent CN116376595A.

[0148] According to the comparison between process 1# and process 3# to process 12#, it can be seen that the same amount of magnetic catalyst added and reaction conditions will directly affect the conversion rate of the primary hydrogenation product. Moreover, since the magnetic catalyst catalyzes in step (1), it will not only affect the test results of the primary hydrogenation product, but also affect the results of the secondary hydrogenation upgrading product and bio-jet fuel. Therefore, the properties of the magnetic catalyst play a key role in the quality of bio-jet fuel.

[0149] According to the comparison between process 1# and process 4#, the weight ratio of Fe3O4 magnetic particles to tert-butylpropylaminotrimethoxysilane will affect the content of molybdenum metal on the surface of the magnetic catalyst. If the amount of tert-butylpropylaminotrimethoxysilane is too much, the steric hindrance effect will increase due to the large number of tert-butyl groups carried on the magnetic catalyst, resulting in a decrease in the catalytic efficiency and conversion rate, an increase in the freezing point of bio-jet fuel, and an increase in the rate of change of the data in Table 5. At the same time, the recovery rate of the magnetic catalyst will also decrease.

[0150] According to the comparison between process 1#, process 5# and process 6#, the chain length of long-chain alkanes in epoxyalkanes will affect the conversion rate and the final performance of bio-jet fuel. If the chain length is too short or too long, the conversion rate will decrease and the freezing point of bio-jet fuel will increase.

[0151] According to the comparison between process 1#, process 7# and process 8#, it can be seen that different silane substances in the preparation of intermediate A will directly affect the catalytic performance of the magnetic catalyst, and affect the magnetic catalyst's ability to resist impurities and the final recovery rate.

[0152] According to the comparison between process 1# and process 9#, when a pure loaded, non-chemically linked magnetic catalyst is used, the catalytic effect on waste grease and the recovery rate of the magnetic catalyst will also be affected. In addition, since there is no chemical connection between the molybdenum-based ionic liquid and the magnetic particles, the molybdenum-based ionic liquid will be removed during long-term production, resulting in a significant decrease in the parameters in Table 5.

[0153] According to the comparison between process 1# and process 10#, comparative process 1# and comparative process 2#, it can be seen that the current liquid catalyst without magnetic particles is difficult to recover, so it needs to be replenished after each batch of production, which is difficult to meet the needs of industrial production.

[0154] A comparison of Process 1#, Process 11#, and Process 12# shows that the catalytic performance of magnetic catalysts formed from other metals is reduced, resulting in a conversion rate of less than 90%. Therefore, industrial production will result in waste of raw materials. In addition, the freezing point of the resulting biojet fuel is increased, and the rate of change of the various parameters after continuous operation in Table 5 is also significantly increased, making it difficult to meet the requirements of industrial use.

[0155] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0156] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for producing bio-jet fuel using waste oil, characterized in that: The steps include: (1) Pre-treating the waste oil in a pre-treatment device, and then mixing it with a magnetic catalyst loaded with an ionic liquid and entering into a suspended bed pre-hydrogenation reactor for a pre-hydrogenation reaction to obtain a pre-hydrogenated product. After the pre-hydrogenation reaction is completed, the magnetic catalyst loaded with an ionic liquid is fixed in the suspended bed pre-hydrogenation reactor under a magnetic field and used for a long period of time, wherein the carrier of the magnetic catalyst loaded with an ionic liquid is Fe3O4 magnetic particles coated with a silicon dioxide layer, and the ionic liquid is a platinum-based ionic liquid; (2) performing gas-liquid separation and non-hydrogenation post-treatment separation on the pre-hydrogenation product to obtain a primary hydrogenation product; (3) The primary hydrogenation product enters a hydrogenation upgrading reactor containing a solid catalyst to obtain an upgraded intermediate product; (4) The upgraded intermediate product enters the hydrogen stripping tower to separate the gaseous product to obtain the secondary hydrogenation upgraded product; (5) The secondary hydrogenation upgrading product enters the hydroisomerization reactor, reacts under the catalysis of a reduced catalyst, and is fractionated to obtain bio-jet fuel.

2. The method for producing bio-jet fuel from waste oil and fat according to claim 1, characterized in that: The preparation method of the magnetic catalyst loaded with ionic liquid is as follows: S1: Disperse the structure-directing agent hexadecyltrimethylammonium bromide in a solvent, add Fe3O4 magnetic particles, sonicate for a certain period of time, add deionized water, add tetraethyl orthosilicate and tert-butylpropylaminotrimethoxysilane under vigorous stirring, react for a certain period of time, separate and collect the product using an external magnet, and wash to obtain intermediate A; S2: adding the intermediate A to a solution containing an epoxyalkane compound, stirring and reacting at 70-80° C. for at least 16 hours, separating and collecting the product using an external magnet, and washing to obtain the carrier; S3: adding the carrier to a solution containing molybdic acid, stirring for reaction, separating and collecting the product by an external magnet, and washing to obtain the magnetic catalyst loaded with the ionic liquid.

3. The method for producing bio-jet fuel from waste oil and fat according to claim 2, characterized in that: In step S1, the weight ratio of Fe3O4 magnetic particles to tetraethyl orthosilicate is 1:(6-8); The weight ratio of Fe3O4 magnetic particles to structure-directing agent hexadecyltrimethylammonium bromide is 1:(0.5-1).

4. The method for producing bio-jet fuel from waste oil and fat according to claim 2, characterized in that: In step S1, the weight ratio of Fe3O4 magnetic particles to tert-butylpropylaminotrimethoxysilane is 1:(2-3).

5. The method for producing bio-jet fuel from waste oil and fat according to claim 2, characterized in that: The epoxyalkane in step S2 is selected from at least one of 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, and 1,2-epoxytetradecane.

6. The method for producing bio-jet fuel from waste oil and fat according to claim 2, characterized in that: In step S2, the weight ratio of the intermediate A to the epoxyalkane is 1:(1-1.5).

7. The method for producing bio-jet fuel from waste oil and fat according to claim 2, characterized in that: In step S3, the weight ratio of the carrier to molybdic acid is 1:(0.8-1.2); In step S3, after the carrier is added to the solution containing molybdic acid, the reaction is stirred at 20-30° C. for 5-6 hours, and then stirred at 50-60° C. for 12-15 hours.

8. The method for producing bio-jet fuel from waste oil and fat according to claim 1, characterized in that: The amount of the magnetic catalyst loaded with ionic liquid added in step (1) is 300 to 1000 ppm; The hourly space velocity of the reaction liquid in step (3) is 0.2 to 3.0 h -1 ; The reaction liquid hourly space velocity in step (5) is 0.2~3.0h -1 .

9. The method for producing bio-jet fuel from waste oil and fat according to claim 1, characterized in that: The pressure of the suspended bed pre-hydrogenation reactor in step (1) is 2-8 MPa and the temperature is 340-360° C.; The pressure of the hydrogenation reactor in step (3) is 2-8 MPa and the temperature is 310-330°C; The pressure of the hydroisomerization reactor in step (5) is 2-8 MPa and the temperature is 280-320°C.

10. A system for producing bio-jet fuel using waste oil, characterized in that: The method for producing bio-jet fuel from waste oil and fat as claimed in any one of claims 1 to 9 comprises: A raw material storage tank, wherein the raw material storage tank is used to store waste oil; A pre-processor, which is used to remove impurities from waste grease; A suspended bed pre-hydrogenation reactor, wherein the inlet of the suspended bed pre-hydrogenation reactor is connected to the pre-treatment device, the suspended bed pre-hydrogenation reactor is further provided with a magnetic field component, the magnetic field component is energized to form a magnetic field in the suspended bed pre-hydrogenation reactor, and the outlet of the suspended bed pre-hydrogenation reactor is sequentially connected to a gas-liquid separator and a non-hydrogenation treatment device; a hydro-upgrading reactor, wherein the inlet of the hydro-upgrading reactor is connected to the non-hydrogenation processor, and the outlet is connected to the hydro-stripping tower; The hydroisomerization reactor has an inlet connected to a hydrogen stripping tower, and an outlet connected to a fractionator, and the outlet of the fractionator distills out bio-jet fuel.

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