Method for in situ production of aromatics from lipid hydrodeoxygenation and biofuel containing aromatics

Abstract

The application belongs to the technical field of biofuel preparation, and specifically discloses a method for in-situ generation of aromatic hydrocarbons by oil and fat hydrogenation deoxygenation. The method uses a composite catalyst composed of NiMgO3 / C-R and Ni / HZSM-5, and oil and fat raw materials and the composite catalyst are added into a reaction kettle in different mass ratios. Under certain temperature and pressure conditions, aromatic hydrocarbons are generated in-situ in the hydrogenation deoxygenation process through the synergistic effect of the double catalysts. The method solves the technical defects of the traditional hydrogenation treatment ester and fatty acid process, which can only generate alkanes and lacks aromatic hydrocarbons. The preparation method does not need to additionally add an aromatic hydrocarbon synthesis unit, and can generate biofuel rich in aromatic hydrocarbons in a single reaction process. The content of aromatic hydrocarbons in the product can reach 16.82% to 25.12%, which significantly improves the density, thermal stability and energy density of the biofuel. The method is suitable for various oil and fat raw materials such as fatty acid methyl ester and soybean oil, and the conversion rates of various raw materials are all over 96%. The process is simple and efficient, and is suitable for the industrialized production of high-end biofuels such as bioaviation kerosene.

Description

Technical Field

[0001] This application relates to the field of biofuel preparation technology, specifically to a method for in-situ generation of aromatics from oils via hydrogenation and deoxygenation, and aromatic-containing biofuels. Background Technology

[0002] With the global energy crisis and the increasing urgency of environmental protection, the development of renewable alternative fuels has become a global consensus. Biofuels, especially hydrocarbon fuels produced from oils and fats, have received widespread attention as an alternative to traditional fossil fuels due to their carbon neutrality and renewability.

[0003] Among them, the hydroprocessed esters and fatty acids (HEFA) process is currently the mainstream and relatively mature technology route for converting oils and fats into biofuels. The core of this process is to convert oil and fat feedstocks (such as vegetable oils, fatty acid methyl esters, etc.) into alkane fuel components through the hydrodeoxygenation action of a catalyst in the presence of high-pressure hydrogen. This process has advantages such as wide feedstock adaptability and mature reaction.

[0004] While traditional HEFA processes have advantages such as wide adaptability of raw materials and well-defined reaction pathways, their product composition has a significant and critical technical drawback: The products are mainly straight-chain and branched alkanes, with extremely low or even zero aromatic content. However, aromatics are an indispensable key component in high-performance fuels, especially aviation kerosene. Their molecular structure can significantly improve fuel density, thermal stability, and energy density, which is a necessary condition for meeting the performance requirements of aviation fuels. Therefore, biofuels produced entirely by the HEFA process typically have lower densities due to the lack of aromatics, and some key properties cannot fully meet the stringent aviation fuel standards, limiting their direct application as "ready-to-use" bio-aviation fuels.

[0005] To compensate for this deficiency, existing industrial practices or technical solutions typically employ two strategies: One method is to purchase additional aromatic components (such as light cycle oil) from petroleum-based products and physically mix and blend them with HEFA products; Secondly, an additional independent aromatics production unit can be added downstream of the HEFA process, for example, to produce the required aromatics through catalytic reforming of alkanes or aromatization of olefins, and then blend them.

[0006] These two post-processing strategies not only increase the complexity of the process and the cost of equipment investment, but also introduce additional energy consumption and may reduce the overall carbon efficiency. They have obvious shortcomings in terms of economics and process simplicity, which restricts the large-scale, low-cost production of bio-aviation fuels.

[0007] To address this issue, researchers have attempted to improve catalyst design. However, most existing studies focus on optimizing single hydrodeoxygenation catalysts, which only improves the yield and selectivity of alkanes but fails to fundamentally solve the problem of product homogeneity and the lack of aromatics in the products. Therefore, currently, there is no mature technology that can efficiently and selectively generate aromatics in situ within the hydrodeoxygenation reaction system of oils and fats.

[0008] In summary, developing a method to efficiently and in-situ catalytically generate desired aromatics during the hydrodeoxygenation of oils and fats, thereby achieving the production of complete and compliant biofuels through a single process, has become a critical technological bottleneck that urgently needs to be overcome in this field. This would not only simplify the production process and reduce production costs, but also strongly promote the industrialization of biofuels. Summary of the Invention

[0009] To address the aforementioned technical problems, this application provides a method for in-situ generation of aromatics through the hydrodeoxygenation of oils and fats. By constructing a specific composite catalyst system, aromatics are generated in situ during the same hydrodeoxygenation process of oils and fats, overcoming the technical deficiency of traditional HEFA processes that only produce alkanes. This method simplifies the production process, reduces production costs, and simultaneously improves the overall performance of biofuels, meeting the requirements for aviation fuel. Specifically, it is applicable to the industrial production of high-end biofuels such as bio-aviation kerosene, effectively solving the problem of insufficient performance of traditional biofuel products. The technical solution is as follows: This application provides a method for in-situ hydrodeoxygenation of oils to produce aromatics, employing a composite catalyst composed of NiMgO3 / CR and Ni / HZSM-5. Utilizing the synergistic effect of the two catalysts, the method achieves simultaneous hydrodeoxygenation of oils and in-situ aromatics production under specific reaction conditions. The method specifically includes the following steps: In-situ reaction: The oil raw material and the composite catalyst are subjected to hydrogenation, deoxygenation, cyclization and aromatization reactions in the same reaction vessel under a hydrogen atmosphere to obtain a product containing aromatics in one step; The composite catalyst comprises a NiMgO3 / CR catalyst and a Ni / HZSM-5 catalyst, wherein the mass ratio of the NiMgO3 / CR catalyst to the Ni / HZSM-5 catalyst is (0.1-0.9):(0.9-0.1). In the in-situ reaction process, the NiMgO3 / CR catalyst catalyzes the hydrodeoxygenation of oils to produce alkanes, and the Ni / HZSM-5 catalyst catalyzes the dehydrogenation, cyclization, and aromatization of alkanes to produce aromatics.

[0010] In some embodiments, the composite catalyst is formed by physically mixing NiMgO3 / CR catalyst and Ni / HZSM-5 catalyst at a mass ratio of (0.1-0.9):(0.9-0.1).

[0011] In some embodiments, in the in-situ reaction step, the reaction vessel is first filled with a hydrogen atmosphere and no air residue is left before the reaction. Then, the reaction is carried out at a reaction temperature of 340-360°C and a hydrogen pressure of 1.9-2.1 MPa for 2.9-3.1 h. During the reaction, the NiMgO3 / CR catalyst catalyzes the hydrogenation and deoxygenation of the oil to produce alkanes, and the Ni / HZSM-5 catalyst catalyzes the dehydrogenation, cyclization, and aromatization of alkanes to produce aromatics. The mass ratio of the oil feedstock to the composite catalyst is 10:1.

[0012] In some embodiments, the molar ratio of Ni to Mg in the NiMgO3 / CR catalyst is 1:3, and its support is a carbon-MgO dual support.

[0013] In some embodiments, the Ni element loading in the Ni / HZSM-5 catalyst is 9.9 to 10.1 wt%, and its support is HZSM-5 molecular sieve.

[0014] In some embodiments, the NiMgO3 / CR catalyst is prepared by in-situ impregnation and then reduced under an H2 / Ar atmosphere; wherein the reduction conditions are 790–810 °C for 2.9–3.1 hours.

[0015] In some embodiments, the oil is one or more of fatty acid methyl esters, soybean oil, palm oil, oleic acid, and stearic acid, and the raw materials do not require additional pretreatment and can be used directly in the reaction.

[0016] In some embodiments, the mass ratio of the NiMgO3 / CR catalyst to the Ni / HZSM-5 catalyst is from 0.1:0.9 to 0.5:0.5. For example, 0.1:0.9, 0.3:0.7, and 0.5:0.5.

[0017] In some embodiments, the mass ratio of the NiMgO3 / CR catalyst to the Ni / HZSM-5 catalyst is 0.3:0.7 to 0.7:0.3; the aromatic selectivity is optimal when the mass ratio is 0.1:0.9.

[0018] In some embodiments, the following steps are included: Preparation of composite catalyst: NiMgO3 / CR catalyst and Ni / HZSM-5 catalyst were mixed uniformly at a mass ratio to obtain composite catalyst; Reaction system setup: Add the oil raw materials and composite catalyst to the high-pressure reactor in the mass ratio, and after shutting down the high-pressure reactor, introduce hydrogen to replace the air inside; wherein, hydrogen replaces the air until no air remains; In-situ reaction: The reaction was carried out at a temperature of 340–360 °C and a hydrogen pressure of 1.9–2.1 MPa for 2.9–3.1 h. During the reaction, the NiMgO3 / CR catalyst catalyzed the hydrogenation and deoxygenation of oil to produce alkanes, and the Ni / HZSM-5 catalyst catalyzed the dehydrogenation, cyclization and aromatization of alkanes to produce aromatics through its acidic sites. Product separation: After the reaction is completed, the product is cooled to room temperature and filtered to remove the catalyst, yielding a biofuel product containing aromatics.

[0019] In some embodiments, the hydrogen in the reactor is replaced three times to ensure that no air remains in the reactor.

[0020] This application provides an aromatic biofuel, which is prepared by the method described above.

[0021] In some embodiments, the aromatic biofuel contains 16.82% to 25.12% aromatics by mass, wherein the aromatic types include C7-C12 monocyclic aromatics and polycyclic aromatics.

[0022] Compared with the prior art, the solution of this application has the following advantages: The method for in-situ generation of aromatics from oils via hydrodeoxygenation provided in this application does not require the addition of an additional aromatic synthesis unit. Through the synergistic effect of two catalysts, oils are efficiently converted into aromatic-rich biofuels in a single reaction process. The aromatic content in the product can reach 16.82% to 25.12%, which significantly improves the density, thermal stability and energy density of the biofuel. Moreover, this method is suitable for various oil feedstocks such as fatty acid methyl esters and soybean oil, and the conversion rate of various feedstocks exceeds 96%.

[0023] This method is simple and efficient, requiring no additional aromatic synthesis unit, and overcomes the technical deficiency of traditional HEFA processes that only produce alkanes (with extremely low or even zero aromatic content). It effectively simplifies the production process, reduces production costs, and improves the overall performance of biofuels to meet the requirements for aviation fuel. It is suitable for the industrial production of high-end biofuels such as bio-aviation kerosene and can effectively solve the problem of insufficient performance of traditional biofuel products. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0025] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods, and the reagents, materials and equipment used are all commercially available.

[0026] This application also provides the following embodiments and comparative examples: (I) Experimental materials and equipment Raw materials: fatty acid methyl ester (FAME), soybean oil, palm oil, oleic acid, stearic acid; NiMgO3 / CR catalyst (self-made, Ni / Mg molar ratio 1:3), Ni / HZSM-5 catalyst (self-made, Ni loading 10wt%); hydrogen.

[0027] Equipment: 50mL high-pressure reactor, agate mortar and pestle, vacuum filtration device, gas chromatography-mass spectrometry (GC-MS / FID, Agilent 8890).

[0028] The NiMgO3 / CR catalyst was prepared by in-situ impregnation and then reduced at 800℃ for 3 hours in an H2 / Ar atmosphere. The Ni / Mg molar ratio was 1:3, and the support was a carbon-MgO dual support. The specific preparation process of the NiMgO3 / CR catalyst is as follows: In-situ impregnation process: First, nickel acetate and magnesium acetate are dissolved in 25 ml of deionized water and stirred for 20 minutes. Then, 10 g of coconut shell carbon is added and stirred for 6 hours. After stirring, the mixture is dried in an oven overnight. Then, the dried precursor powder is reduced at 800℃ in an H2 / Ar atmosphere for 3 hours to obtain the final product. The Ni / Mg molar ratio is 1:3.

[0029] The Ni / HZSM-5 catalyst has a Ni loading of 10 wt% and is supported by HZSM-5 molecular sieve. The specific preparation process is as follows: nickel acetate is dissolved in 25 ml of deionized water and stirred for 20 minutes. Then, 10 g of HZSM-5 is added, and the mixture is stirred for 6 hours. After stirring, the mixture is dried in an oven overnight. The dried precursor powder is then reduced at 800℃ in an H2 / Ar atmosphere for 3 hours to obtain the final product.

[0030] (II) Implementation Examples and Comparative Examples Example 1: Using fatty acid methyl esters as raw materials 1. Preparation of composite catalyst: Take 0.3g of NiMgO3 / CR catalyst and 0.7g of Ni / HZSM-5 catalyst, place them in an agate mortar and mix them evenly to obtain 1.0g of composite catalyst.

[0031] 2. Reaction system setup: Add 10 g of fatty acid methyl ester and 1.0 g of the above composite catalyst to a 50 mL high-pressure reactor. After closing the reactor, purge with hydrogen three times.

[0032] 3. Reaction implementation: Set the reaction temperature to 350℃, hydrogen pressure to 2MPa, and stirring speed to 400rpm, and react for 3h.

[0033] 4. Product separation and detection: After the reaction is completed, the product is cooled to room temperature, filtered to remove the catalyst, and analyzed by GC-MS / FID.

[0034] The results showed that the conversion rate of fatty acid methyl esters was 96.12%, the aromatic content of the product was 16.82%, mainly C7-C12 monocyclic aromatics, the isoparaffin content was 11.74%, and the fuel density was increased to 0.79 g / cm³, which meets the aviation kerosene density standard (0.775~0.840 g / cm³) and meets the performance requirements of aviation kerosene.

[0035] Example 2: Using fatty acid methyl esters as raw materials The only difference from Example 1 is that 1.0 g of composite catalyst was obtained by uniformly mixing 0.5 g of NiMgO3 / CR catalyst and 0.5 g of Ni / HZSM-5 catalyst. During the reaction, 10 g of fatty acid methyl ester and 1.0 g of the above composite catalyst were added to the high-pressure reactor.

[0036] Results showed that the conversion rate of fatty acid methyl esters was 100%, the aromatic content in the product was 18.35%, the ratio of alkanes to aromatics was well-coordinated, and the fuel density was increased to 0.81 g / cm³, which meets the aviation kerosene density standard (0.775~0.840 g / cm³).

[0037] Example 3: Using fatty acid methyl esters as raw materials The only difference from Example 1 is that 1.0 g of composite catalyst was obtained by uniformly mixing 0.1 g of NiMgO3 / CR catalyst and 0.9 g of Ni / HZSM-5 catalyst. During the reaction, 10 g of fatty acid methyl ester and 1.0 g of composite catalyst were added to the high-pressure reactor, and the reaction was carried out under the reaction conditions of Example 1.

[0038] Product testing: The conversion rate of fatty acid methyl esters was 100%, and the aromatic content in the product reached 21.89%, the highest aromatic yield among all raw materials. The aromatic types included monocyclic aromatics and a small amount of polycyclic aromatics. No obvious harmful byproducts were generated, and the product exhibited excellent thermal stability. The ratio of alkanes to aromatics was well-balanced, increasing the fuel density to 0.82 g / cm³, meeting the density standard for aviation kerosene (0.775–0.840 g / cm³).

[0039] Example 4: Using palm oil as raw material The only difference from Example 2 is that the raw material is palm oil.

[0040] Product testing: The palm oil conversion rate was 99.28%, the aromatic content in the product was 24.46%, the ratio of alkanes to aromatics was well-balanced, and the fuel density was increased to 0.83 g / cm³, which meets the density standard for aviation kerosene (0.775~0.840 g / cm³).

[0041] Example 5: Using oleic acid as a raw material The only difference from Example 2 is that the raw material is oleic acid.

[0042] Product testing: The oleic acid conversion rate was 100%, the aromatic content in the product was 25.12%, the ratio of alkanes to aromatics was well-balanced, and the fuel density was increased to 0.82 g / cm³, which meets the aviation kerosene density standard (0.775~0.840 g / cm³).

[0043] Example 6: Using stearic acid as a raw material The only difference from Example 2 is that the raw material is stearic acid.

[0044] Product testing: The stearic acid conversion rate was 100%, the aromatic content in the product was 22.32%, the ratio of alkanes to aromatics was well-balanced, and the fuel density was increased to 0.81 g / cm³, which meets the aviation kerosene density standard (0.775~0.840 g / cm³).

[0045] Example 7: Using soybean oil as raw material The only difference from Example 2 is that the raw material is soybean oil.

[0046] Product testing: The soybean oil conversion rate was 100%, the aromatic content in the product was 20.59%, the ratio of alkanes to aromatics was well-balanced, and the fuel density was increased to 0.82 g / cm³, which meets the density standard for aviation kerosene (0.775~0.840 g / cm³).

[0047] Comparative Example 1: Traditional HEFA process: Single NiMgO3 / CR catalyst The only difference from Example 1 is that a single NiMgO3 / CR catalyst is used, specifically: Catalyst preparation: A single NiMgO3 / CR catalyst was used.

[0048] Reaction implementation: 10 g of fatty acid methyl ester and 1.0 g of NiMgO3 / CR catalyst were added to a high-pressure reactor, and the hydrodeoxygenation reaction was carried out under the reaction conditions of Example 1.

[0049] Product testing: The conversion rate of fatty acid methyl ester is 100%. The product consists only of straight-chain alkanes and contains no aromatic components. The fuel density is 0.75 g / cm³, which is lower than the density requirement of aviation kerosene. Additional aromatics need to be added before it can be used.

[0050] Comparative Example 2: Traditional HEFA process: single NiMgO3 / C catalyst (no hydrogen reduction) The only difference from Example 1 is that a single NiMgO3 / C catalyst is used, specifically: Catalyst preparation: A single NiMgO3 / C catalyst (without hydrogen reduction) was used. The preparation process of the NiMgO3 / C catalyst was as follows: First, nickel acetate and magnesium acetate were dissolved in 25 ml of deionized water and stirred for 20 minutes. Then, 10 g of coconut shell carbon was added, and the mixture was stirred for 6 hours. After stirring, the mixture was dried in an oven overnight. Then, the dried precursor powder was calcined at 800℃ for 3 hours under a nitrogen atmosphere to obtain the catalyst. The Ni / Mg molar ratio was 1:3, and the support was a carbon-MgO dual support.

[0051] Reaction implementation: 10 g of fatty acid methyl ester and 1.0 g of NiMgO3 / C catalyst (without hydrogen reduction) were added to a high-pressure reactor, and the hydrogenation deoxygenation reaction was carried out under the reaction conditions of Example 1.

[0052] Product testing: The conversion rate of fatty acid methyl esters was 91.57%. The product consisted only of straight-chain alkanes and contained no aromatic components. The fuel density was 0.75 g / cm³, which was lower than the density requirement for aviation kerosene. Additional aromatics were required for its use.

[0053] Comparative Example 3: Ni / HZSM-5 Catalyzed Hydrodeoxygenation of Oils The only difference from Example 1 is that a single Ni / HZSM-5 catalyst is used, specifically: Catalyst preparation: A single Ni / HZSM-5 catalyst was used.

[0054] Reaction implementation: 10 g of fatty acid methyl ester and 1.0 g of Ni / HZSM-5 catalyst were added to a high-pressure reactor, and the hydrodeoxygenation reaction was carried out under the reaction conditions of Example 1.

[0055] Product testing: The conversion rate of fatty acid methyl esters was 96.15%. The product contained straight-chain alkanes and aromatics, with an aromatic content of 7.74%. The fuel density was 0.76 g / cm³, which is lower than the density requirement for aviation kerosene. Additional aromatics need to be added before it can be used.

[0056] Test Result Analysis The test results of the above embodiments and comparative examples are summarized in Table 1-2 below: Table 1

[0057] Table 2

[0058] The conversion rate of oilseed raw materials is calculated as follows: Conversion rate (%) = (1 - (product mass)) (mass of added catalyst) × (÷mass of added raw materials) × 100%; The test data sources are: GC-MS / FID, Agilent 8890 test results, and fuel density data from ST-1507A petroleum product density analyzer.

[0059] Results Analysis As can be seen from Examples 1-7, the composite catalyst and method provided in this application, composed of NiMgO3 / CR and Ni / HZSM-5, can achieve efficient conversion (conversion rate 96.12%-100%) of different oil feedstocks (fatty acid methyl esters, soybean oil, palm oil, oleic acid, stearic acid) under uniform reaction conditions, and generate aromatics (16.82%-25.12%) with significant and adjustable content in situ. At the same time, the fuel density of the product (0.79-0.83 g / cm³) meets the aviation kerosene standard.

[0060] Comparative Examples 1 and 2 confirm that using only a hydrodeoxygenation catalyst (regardless of reduction) cannot generate aromatics at all, demonstrating the fundamental limitation of the traditional HEFA process. Comparative Example 3 shows that while using only an aromatization catalyst can generate a small amount of aromatics, its yield (7.74%) is far lower than that of the composite catalyst system in this application. This comprehensively demonstrates the technical superiority and ingenious design of this application, which achieves a one-step tandem reaction of "hydrodeoxygenation" and "aromatization" through the synergistic effect of a specific ratio of bifunctional catalysts.

[0061] In summary, the proposed solution has at least the following design concepts and beneficial effects: Design concept: Traditional HEFA processes are limited by single-function hydrodeoxygenation catalysts, which can only convert oils and fats into alkanes. This application breaks this technological paradigm, and its core concept lies in: A bifunctional synergistic catalytic system was constructed by physically combining a highly efficient hydrodeoxygenation catalyst (NiMgO3 / CR) with a molecular sieve catalyst (Ni / HZSM-5) possessing shape-selective aromatization capabilities. By precisely controlling the ratio of the two catalysts, a series of tandem reactions—dehydrogenation, cyclization, and aromatization—are simultaneously catalyzed by the acidic sites of the molecular sieve catalyst during the hydrodeoxygenation reaction to generate alkane intermediates. This allows for the efficient and targeted conversion of oilseeds into aromatic-rich biofuels within a single reactor and in a single step. The key to this method lies in the complementary functions of the catalysts and the efficient spatiotemporal integration of the reaction sequence.

[0062] Beneficial effects: Achieving in-situ one-step generation of aromatics with revolutionary simplification of process flow: The method of this application eliminates the independent aromatic synthesis or subsequent blending unit required in traditional processes, and directly and in-situ generates the required aromatics in the main hydrodeoxygenation process, which greatly simplifies the process flow and reduces equipment investment and operating costs.

[0063] Significantly improves overall fuel performance: the prepared biofuels can contain 16.82%–25.12% aromatics, while the fuel density is increased to 0.79–0.83 g / cm³. 3 This effectively improves key performance indicators such as fuel energy density and thermal stability, enabling it to meet the specifications of high-end fuels such as aviation kerosene.

[0064] The process conditions are mild and efficient: the method can achieve a raw material conversion rate of over 96% under relatively mild reaction conditions (such as 350°C and 2MPa), with short reaction time, high energy efficiency, and good industrial scale-up potential and economic benefits.

[0065] Wide applicability of raw materials: The method shows excellent adaptability to a variety of common oil raw materials such as fatty acid methyl esters, soybean oil, palm oil, oleic acid, and stearic acid, thus broadening the source of raw materials for biofuels.

[0066] The catalytic synergistic effect is significant and adjustable: Comparative data from examples and comparative examples demonstrate that the specific catalyst combination (NiMgO3 / CR and Ni / HZSM-5) and its ratio in this application produce a synergistic effect of "1+1>2". The aromatic yield is far more than the simple sum of the effects of using the two catalysts individually, and the product composition can be optimized by adjusting the ratio.

[0067] It should be noted that: In this article, “~” is used to represent the range of values, and the range of values ​​represented by this expression includes two endpoint values.

[0068] Apart from the specific choices embodied in the above embodiments, any formulation range described above may be used in the specific implementation of this application, including but not limited to the above embodiment schemes.

[0069] The specific parameters or some commonly used reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments under the concept of this application, and are not intended to limit them; those skilled in the art can make adaptive adjustments within the concept and protection scope of this application.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for in-situ hydrogenation and deoxygenation of oils to generate aromatics, characterized in that, Includes the following steps: In-situ reaction: The oil raw material and the composite catalyst are subjected to hydrogenation, deoxygenation, cyclization and aromatization reactions in the same reaction vessel under a hydrogen atmosphere to obtain a product containing aromatics in one step; The composite catalyst includes a NiMgO3 / CR catalyst and a Ni / HZSM-5 catalyst, and the mass ratio of the NiMgO3 / CR catalyst to the Ni / HZSM-5 catalyst is (0.1-0.9):(0.9-0.1).

2. The method according to claim 1, characterized in that, The composite catalyst is formed by physically mixing NiMgO3 / CR catalyst and Ni / HZSM-5 catalyst at a mass ratio of (0.1-0.9):(0.9-0.1).

3. The method according to claim 1, characterized in that, In the in-situ reaction step, the reaction vessel is first filled with a hydrogen atmosphere and no air residue is left before the reaction. Then, the reaction is carried out at a reaction temperature of 340-360℃ and a hydrogen pressure of 1.9-2.1MPa for 2.9-3.1h. During the reaction, the NiMgO3 / CR catalyst catalyzes the hydrogenation and deoxygenation of oil to produce alkanes, and the Ni / HZSM-5 catalyst catalyzes the dehydrogenation, cyclization, and aromatization of alkanes to produce aromatics. The mass ratio of the oil raw material to the composite catalyst is 10:

1.

4. The method according to claim 1, characterized in that, The molar ratio of Ni to Mg in the NiMgO3 / CR catalyst is 1:3, and its support is a carbon-MgO dual support. The Ni / HZSM-5 catalyst has a Ni loading of 9.9–10.1 wt%, and its support is HZSM-5 molecular sieve.

5. The method according to claim 1, characterized in that, The NiMgO3 / CR catalyst was prepared by in-situ impregnation and then reduced under an H2 / Ar atmosphere; the reduction conditions were 790–810 °C for 2.9–3.1 hours.

6. The method according to claim 1, characterized in that, The oil is one or more of the following: fatty acid methyl ester, soybean oil, palm oil, oleic acid, and stearic acid.

7. The method according to claim 1, characterized in that, The mass ratio of the NiMgO3 / CR catalyst to the Ni / HZSM-5 catalyst is from 0.3:0.7 to 0.7:0.

3.

8. The method according to any one of claims 1-7, characterized in that, Includes the following steps: Preparation of composite catalyst: NiMgO3 / CR catalyst and Ni / HZSM-5 catalyst were mixed uniformly at a mass ratio to obtain composite catalyst; Reaction system setup: Add the oil raw materials and composite catalyst to the high-pressure reactor in the mass ratio, and after shutting down the high-pressure reactor, introduce hydrogen to replace the air inside; wherein, hydrogen replaces the air until no air remains; In-situ reaction: The reaction was carried out at a temperature of 340–360℃ and a hydrogen pressure of 1.9–2.1 MPa for 2.9–3.1 h; Product separation: After the reaction is completed, the product is cooled to room temperature and filtered to remove the catalyst, yielding a biofuel product containing aromatics.

9. An aromatic hydrocarbon-containing biofuel, characterized in that... : The aromatic biofuel is prepared by the method described in any one of claims 1-8.

10. The aromatic hydrocarbon-containing biofuel according to claim 9, characterized in that, The aromatic biofuel contains 16.82% to 25.12% aromatics by mass, including C7-C12 monocyclic aromatics and polycyclic aromatics.

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