Method for preparing aviation fuel from solid-phase aviation fuel precursor

Abstract

The invention discloses a preparation method for preparing aviation fuel from a solid-phase aviation fuel precursor, the preparation method for preparing aviation fuel from the solid-phase aviation fuel precursor adopts the steps of sectional hydrogenation and deoxidation, and comprises the following steps: firstly, pre-hydrogenating the solid-phase aviation fuel precursor to convert the solid-phase aviation fuel precursor into a liquid-phase aviation fuel precursor; moreover, unstable polyunsaturated functional groups on the solid-phase aviation oil precursor are converted into completely saturated functional groups through the pre-hydrogenation step, so that the stability of the solid-phase aviation oil precursor in the subsequent high-temperature deoxidation step is improved, and the possibility of polymerization and coking reaction of the solid-phase aviation oil precursor is reduced; then, a more adaptive Ni-MoOX catalyst is selected for high-temperature deoxidation reaction, complete carbon chains can be reserved, carbon atoms of raw materials are utilized to the maximum extent, the recovery rate of long-chain alkanes is increased, the requirement of aviation fuel for the carbon number range is particularly met, and the problem that in the prior art, the carbon number range is large is solved. And the mass transfer efficiency of the solid-phase raw material and the heterogeneous deoxidation catalyst is low in the presence of hydrogen.

Description

Technical Field

[0001] The present invention relates to the field of bio-aviation fuel, and in particular to a method for preparing aviation fuel from a solid-phase aviation fuel precursor. Background Art

[0002] Traditional aviation fuel is primarily composed of different types of hydrocarbons, primarily hydrocarbon compounds, with linear alkanes, cycloalkanes, and aromatic hydrocarbons as the primary components. However, these are all synthesized from non-renewable petrochemicals. As an alternative to traditional jet fuel, biojet fuel is considered a core technological path to achieving carbon neutrality in the aviation industry due to its renewability, low carbon emissions, and high compatibility with existing aviation infrastructure. Biojet fuel can be synthesized from biomass feedstocks such as waste oils, cellulose, and microalgae, or through electricity-to-fuel technology, with a lifecycle carbon reduction potential of over 80%.

[0003] However, in the existing technology, the mass transfer efficiency between the solid raw material and the heterogeneous deoxidation catalyst is low, and the solid jet fuel precursor is prone to polymerization and coking reactions under high temperature conditions, resulting in reduced production. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing aviation fuel from a solid-phase aviation fuel precursor, so as to solve the problem of low mass transfer efficiency between the solid-phase raw material and the heterogeneous deoxidation catalyst.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing aviation fuel from a solid-phase aviation fuel precursor. The solid-phase aviation fuel precursor is obtained by aldol condensation of furfural and levulinic acid solution, comprising the following steps:

[0007] Pre-hydrogenation: dissolving the solid jet fuel precursor in a solvent and adding a pre-hydrogenation catalyst to a hydrogenation reactor to form a hydrogenation reaction mixture; then introducing hydrogen into the hydrogenation reactor, heating the hydrogenation reaction mixture, and stirring the mixture to allow the reaction solution to undergo a hydrogenation reaction in a hydrogen atmosphere to obtain a hydrogenated liquid product; wherein the pre-hydrogenation catalyst is a Ni metal catalyst;

[0008] Deoxygenation: The hydrogenated liquid product, deoxygenation catalyst and n-decane are added to a deoxygenation reaction kettle to obtain a deoxygenation reaction mixture; hydrogen is then introduced into the deoxygenation reaction kettle, the deoxygenation reaction mixture is heated, and stirred to allow the hydrogenated liquid product to undergo a high-temperature deoxygenation reaction in a hydrogen atmosphere to obtain biomass aviation fuel; the deoxygenation catalyst is Ni-MoO X catalyst.

[0009] Ni metal catalyst is used as a catalyst for the hydrogenation reaction because Ni metal has good catalytic efficiency, good selectivity for the hydrogenation reaction, can effectively control the product distribution of the hydrogenation reaction, and reduce the generation of by-products.

[0010] Using Ni-MoO X The catalyst is used as a catalyst for high temperature deoxidation reaction because Ni-MoO X The catalyst has good high temperature stability and can maintain good catalytic activity in high temperature environment; moreover, the combination of nickel and molybdenum elements makes Ni-MoO X The catalyst has strong oxidizing properties and can effectively promote the oxidation reaction.

[0011] The preparation method splits the hydrodeoxygenation process into two steps: pre-hydrogenation and deoxygenation. More suitable catalysts can be selected according to the hydrogenation and deoxygenation steps, respectively, greatly improving the overall efficiency and lifespan.

[0012] Specifically, in the pre-hydrogenation step, the mass ratio of the solid-phase aviation fuel precursor to the pre-hydrogenation catalyst is (2-8):1.

[0013] The above ratio can effectively promote the hydrogenation reaction, improve the reaction efficiency, and convert the polyunsaturated functional groups into fully saturated functional groups.

[0014] Specifically, in the pre-hydrogenation step, the concentration of the solid-phase aviation fuel precursor in the hydrogenation reaction mixture is 9.1 to 28.6 wt.%, and the solvent is methanol.

[0015] In a specific embodiment of the present invention, methanol is used to dissolve the solid-phase aviation fuel precursor to form a homogeneous solution, which reduces viscosity and improves fluidity, increases the contact efficiency between hydrogen, catalyst and substrate, and accelerates the hydrogenation / deoxygenation reaction rate. Compared with directly hydrogenating and deoxygenating the solid-phase aviation fuel precursor to produce aviation fuel, the aviation fuel yield produced by the present invention is significantly increased, greatly improving production efficiency.

[0016] Specifically, the reaction temperature of the hydrogenation reaction is 160 to 200° C., the reaction time of the hydrogenation reaction is 6 to 12 hours, and the hydrogenation reaction is carried out under an initial hydrogen pressure of 3.9 to 4.1 MPa.

[0017] In a specific embodiment of the present invention, the hydrogenation reaction is carried out at an initial hydrogen pressure of 4.0 MPa, and the hydrogen is introduced after three gas replacements. The above reaction temperature and reaction time can effectively control the product distribution of the hydrogenation reaction and reduce the formation of by-products.

[0018] Specifically, in the deoxygenation step, the mass ratio of the hydrogenation product to the deoxygenation catalyst in the deoxygenation reaction is 5:1.

[0019] Adopting the above ratio can effectively promote the high-temperature deoxygenation reaction, improve the reaction efficiency, maintain a high selectivity, avoid over-oxidation or the generation of by-products, make the reaction more efficient, and improve the recovery rate of long-chain alkanes.

[0020] Specifically, in the deoxygenation step, the reaction temperature of the high-temperature deoxygenation reaction is 278-282° C., the reaction time of the high-temperature deoxygenation reaction is 23-24.5 h, and the high-temperature deoxygenation reaction is carried out under an initial hydrogen pressure of 4.9-5.1 MPa.

[0021] In a specific embodiment of the present invention, the high-temperature deoxygenation reaction is carried out at an initial hydrogen pressure of 4.0 MPa, and the gas is replaced three times during the introduction of hydrogen before the high-temperature deoxygenation reaction is carried out. Using these reaction temperatures and reaction times effectively controls the product distribution of the high-temperature deoxygenation reaction and reduces the formation of by-products.

[0022] Specifically, in the deoxygenation step, the deoxygenation reaction mixture comprises, calculated by weight, 1 to 2 parts of hydrogenated liquid product, 0.3 to 0.4 parts of deoxygenation catalyst and 1.4 to 1.5 parts of n-decane solvent.

[0023] In a specific embodiment of the present invention, the deoxygenation reaction mixture includes, by weight, 2 parts of hydrogenated liquid product, 0.4 parts of deoxygenation catalyst and 1.45 parts of n-decane solvent.

[0024] Specifically, the carbon chain length of the solid-phase aviation fuel precursor is 12 to 15.

[0025] The solid-phase aviation fuel precursor is obtained by condensing furfural and levulinic acid solution through aldol condensation. The carbon chain length of the solid-phase aviation fuel precursor is 12 to 15, wherein the solid-phase aviation fuel precursor is mainly C 15 The solid phase condensation product, C 15 The chemical structure of the solid phase condensation product is:

[0026]

[0027] A technical solution in the present invention can have the following beneficial effects:

[0028] The method for preparing aviation fuel from a solid-phase aviation fuel precursor adopts a staged hydrogenation and deoxygenation step. The solid-phase aviation fuel precursor is first pre-hydrogenated to convert the solid-phase aviation fuel precursor from a solid phase to a liquid phase. In addition, the pre-hydrogenation step converts unstable C=O / C=C functional groups in the solid-phase aviation fuel precursor into saturated CO / CC functional groups, thereby improving the stability of the solid-phase aviation fuel precursor in a subsequent high-temperature deoxygenation step and improving the polymerization and coking phenomena of unsaturated functional groups under high-temperature reaction. Subsequently, a more suitable Ni-MoOX The catalyst undergoes a high-temperature deoxidation reaction, efficiently removing oxygen atoms from the precursor to produce fully saturated straight-chain / branched-chain hydrocarbon components. The density of the prepared aviation fuel is greater than 0.8g / cm 3 It is a high-density aviation fuel that particularly meets the carbon number range requirements of aviation fuel, and solves the problem of low mass transfer efficiency between solid-phase raw materials and heterogeneous deoxygenation catalysts under hydrogen conditions in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a gas chromatogram of the hydrogenated liquid product of Example 1 of the present invention;

[0030] Figure 2 is a gas chromatogram of the hydrogenated liquid product of Example 2 of the present invention;

[0031] Figure 3 is a gas chromatogram of the hydrogenated liquid product of Example 3 of the present invention;

[0032] Figure 4 is a gas chromatogram of the hydrogenated liquid product of Example 4 of the present invention;

[0033] Figure 5 is a gas chromatogram of the hydrogenated liquid product of Example 5 of the present invention;

[0034] Figure 6 is a gas chromatogram of the hydrogenated liquid product of Example 6 of the present invention;

[0035] Figure 7 is a gas chromatogram of the hydrogenated liquid product of Example 7 of the present invention;

[0036] Figure 8 is a gas chromatogram of the hydrogenated liquid product of Example 8 of the present invention;

[0037] Figure 9 is a gas chromatogram of the hydrogenated liquid product of Example 9 of the present invention;

[0038] Figure 10 is a gas chromatogram of the hydrogenated liquid product of Example 10 of the present invention;

[0039] Figure 11 is a gas chromatogram of the hydrogenated liquid product of Example 11 of the present invention;

[0040] Figure 12 is a gas chromatogram of the product of Example 12 of the present invention;

[0041] Figure 13 is a gas chromatogram of the product of Example 12 of the present invention;

[0042] Figure 14 is a gas chromatogram of the product of Example 12 of the present invention;

[0043] Figure 15 is a gas chromatogram of the product of Comparative Example 1 of the present invention;

[0044] Figure 16 is the XRD spectrum of the Ni-MoOx catalyst in the present invention;

[0045] Figure 17 This is the structural formula of the main product in biomass aviation fuel. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be further illustrated below by way of specific embodiments. To facilitate understanding of the present invention, the present invention will be described in more detail below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0047] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] Example Group A1

[0050] A method for preparing aviation fuel from a solid-phase aviation fuel precursor includes a pre-hydrogenation step, comprising the following operations:

[0051] According to the ratio in Table 1, 25wt.% solid-phase jet fuel precursor was dissolved in 25ml methanol solvent, and a pre-hydrogenation catalyst was added to a hydrogenation reactor with a capacity of 50mL to form a hydrogenation reaction mixture; hydrogen was then introduced into the hydrogenation reactor, and after the hydrogen was introduced to replace the gas three times, hydrogen was filled into the hydrogenation reactor to 4MPa, the hydrogenation reaction mixture was heated, and stirred to allow the reaction solution to undergo hydrogenation reaction in a hydrogen atmosphere to obtain a hydrogenated liquid product; wherein the pre-hydrogenation catalyst was a Ni metal catalyst. After the reaction was completed, the temperature was lowered to room temperature, the supernatant was filtered, and the product was detected and analyzed by gas chromatography. The gas chromatographic results of the hydrogenated liquid product were as follows: Figures 1 to 11 shown.

[0052] Table 1 - Specific parameters in the pre-hydrogenation step

[0053]

[0054]

[0055] The pre-hydrogenation process parameters were optimized, and the catalytic effect and substrate concentration were taken into consideration. The hydrogenated liquid product obtained in Example 10 was selected to proceed to the deoxygenation step in the subsequent Example 12.

[0056] Example 12

[0057] 2 g of hydrogenated liquid product, 0.4 g of Ni-MoOx catalyst, and 20 mL of n-decane were added to a 50 mL deoxygenation reactor. After hydrogen was introduced to replace the gas three times, hydrogen was filled into the deoxygenation reactor to 5 MPa, and the temperature was raised to 280°C and stirred for 24 hours to obtain biomass aviation fuel.

[0058] Comparative Example 1

[0059] 2g of the aviation fuel intermediate, 0.4g of Ni / Mo catalyst, and 20mL of n-decane were added to a 50mL reactor. After hydrogen was introduced three times to replace the atmosphere, the atmosphere was filled with hydrogen to 5MPa. The temperature was raised to 280°C and stirred for 24 hours to produce aviation fuel. The aviation fuel intermediate was a solid-phase aviation fuel precursor.

[0060] After the reaction of Example 12 and Comparative Example 1 was completed, the temperature was lowered to room temperature, the supernatant of Example 12 and Comparative Example 1 was filtered, and the product was detected and analyzed by gas chromatography three times. The results are shown in Table 2; the product of Example 12 was analyzed by gas chromatography three times, and the gas chromatogram was as shown in Table 2. Figures 12-14 As shown; Comparative Example 1 was subjected to gas chromatography analysis, and the gas chromatogram was as shown Figure 15 shown.

[0061] Table 2 - Product Detection Analysis

[0062]

[0063] As shown in Table 2, the aviation fuel produced by this invention primarily consists of C12-C15 components, fully meeting the carbon chain length requirements for aviation fuel hydrocarbon components. The yield is as high as over 52%, demonstrating distinct technical characteristics and promising application potential. The aviation fuel intermediate prepared in Comparative Example 1 was directly subjected to hydrodeoxygenation. Example 12 achieved a higher conversion rate and a higher C15 content than Comparative Example 1.

[0064] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will be able to devise other specific embodiments of the present invention without inventive effort, and such equivalent variations or substitutions are intended to be encompassed within the scope of the claims of this application.

Claims

1. A method for preparing aviation fuel from a solid-phase aviation fuel precursor, wherein the solid-phase aviation fuel precursor is obtained by aldol condensation of furfural and levulinic acid solution, characterized in that: The following steps are involved: Pre-hydrogenation: dissolving the solid jet fuel precursor in a solvent and adding a pre-hydrogenation catalyst to a hydrogenation reactor to form a hydrogenation reaction mixture; then introducing hydrogen into the hydrogenation reactor, heating the hydrogenation reaction mixture, and stirring the mixture to allow the reaction solution to undergo a hydrogenation reaction in a hydrogen atmosphere to obtain a hydrogenated liquid product; wherein the pre-hydrogenation catalyst is a Ni metal catalyst; Deoxygenation: The hydrogenated liquid product, deoxygenation catalyst and n-decane are added to a deoxygenation reaction kettle to obtain a deoxygenation reaction mixture; hydrogen is then introduced into the deoxygenation reaction kettle, the deoxygenation reaction mixture is heated, and stirred to allow the hydrogenated liquid product to undergo a high-temperature deoxygenation reaction in a hydrogen atmosphere to obtain biomass aviation fuel; the deoxygenation catalyst is Ni-MoO X catalyst.

2. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the pre-hydrogenation step, the mass ratio of the solid-phase aviation fuel precursor to the pre-hydrogenation catalyst is (2-8):

1.

3. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the pre-hydrogenation step, the concentration of the solid-phase aviation fuel precursor in the hydrogenation reaction mixture is 9.1-28.6 wt.%, and the solvent is methanol.

4. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the pre-hydrogenation step, the reaction temperature of the hydrogenation reaction is 160-200° C., the reaction time of the hydrogenation reaction is 6-12 hours, and the hydrogenation reaction is carried out under an initial hydrogen pressure of 3.9-4.1 MPa.

5. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the deoxygenation step, the mass ratio of the hydrogenation product to the deoxygenation catalyst in the deoxygenation reaction is 5:

1.

6. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the deoxidation step, the reaction temperature of the high-temperature deoxidation reaction is 278-282° C., the reaction time of the high-temperature deoxidation reaction is 23-24.5 h, and the high-temperature deoxidation reaction is carried out under an initial hydrogen pressure of 4.9-5.1 MPa.

7. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: In the deoxygenation step, the deoxygenation reaction mixture comprises, calculated by weight, 1 to 2 parts of hydrogenated liquid product, 0.3 to 0.4 parts of deoxygenation catalyst and 1.4 to 1.5 parts of n-decane solvent.

8. The method for preparing aviation fuel from a solid-phase aviation fuel precursor according to claim 1, characterized in that: The carbon chain length of the solid-phase aviation fuel precursor is 12 to 15.

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