Process method for preparing sustainable aviation fuel based on biomass raw materials

Abstract

The invention relates to the technical field of aviation fuel, in particular to a process method for preparing sustainable aviation fuel based on biomass raw materials, which adopts the biomass raw materials as a basis, and is more favorable for realizing carbon emission reduction, reducing waste emission, improving carbon conversion rate and reducing energy consumption in the preparation process. Specifically, in the preparation process of the platform compound, solid acid is adopted, so that the wastewater amount is reduced, distillation purification is not needed, and the energy consumption is reduced; the residual biomass after steam stripping and hydrolysis is recycled, the carbon element in the biomass is fully utilized, the problems that the traditional biomass raw material is difficult to grind and the carbon conversion rate is relatively low can be effectively solved, the coking phenomenon in the gasification process by directly adopting the biomass raw material is reduced, the biological gasification difficulty is reduced, and the energy consumption is reduced. Compared with aviation fuel prepared from biomass at present, the prepared biomass aviation fuel has more full fractions, the fractions of the biomass aviation fuel are the same as or even better than those of existing petrochemical-based aviation fuel, and the biomass aviation fuel has very excellent practical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation fuel, and in particular to a process for preparing sustainable aviation fuel based on biomass raw materials. Background Art

[0002] Jet fuel is a traditional aviation fuel typically extracted from crude oil and processed through processes such as hydrogenation, distillation, catalytic cracking, and deoxygenation. However, as environmental and climate issues caused by carbon emissions become increasingly serious, carbon emission reduction has become a focus of public attention, with the aviation industry being a key sector of focus. Biomass-based aviation fuel technology is gaining significant attention. Biomass-based aviation fuel is produced from resources such as forestry residues, agricultural waste, waste cooking oils and fats, and municipal solid waste, recycling the carbon stored in the biomass feedstock to achieve emission reductions.

[0003] There are many research methods for biomass-based aviation fuel. Most of them have the problems of generating a lot of waste residue and wastewater and high energy consumption. A large amount of carbon source in the waste residue is wasted and the utilization conversion rate is low. During their long-term research and development, the inventors discovered that the biomass gasification plus FT synthesis process offers potential research prospects. However, currently, there are no suitable biomass gasifiers, and existing coal gasifiers cannot be used directly for gasification. This is due to the significant differences between biomass and coal. Compared to coal, biomass has a lower density, requiring compression and pelletization to increase bulk density before biogasification. Furthermore, biomass raw materials contain large amounts of cellulose, high alkali metals, high chlorine content, and high volatility, which makes gasification more prone to coking, equipment corrosion, and difficulty in grinding. Currently, coal gasification equipment primarily includes fixed-bed, fluidized-bed, and entrained-bed. Directly gasifying biomass in a coal gasifier can lead to coking in fixed beds and significant carbon loss in fluidized beds. Entrained-bed systems offer high efficiency, but require high raw material pretreatment and require grinding and pulverization. Furthermore, the aviation fuel produced in this research direction is primarily composed of straight-chain alkanes, which differ significantly from the fractions of petrochemical-based aviation fuel. This means that biomass aviation fuel can only be used in a blended form with petrochemical-based aviation fuel, thus limiting its further promotion.

[0004] Therefore, based on the above problems, it is of great significance to develop a full-fraction biomass aviation fuel that has high carbon conversion rate, low energy consumption and reduced waste generation and can be used directly without blending. Summary of the Invention

[0005] In response to the technical problems in the prior art, the purpose of the present invention is to provide a process for preparing sustainable aviation fuel based on biomass raw materials, which solves the problems of low carbon conversion rate, high energy consumption and large amount of waste in the current biomass aviation fuel preparation process.

[0006] To achieve the above objectives, the technical solution provided by the present invention is: The present invention provides a process for preparing sustainable aviation fuel based on biomass raw materials, comprising the following steps: Step 1: Preparation of aviation fuel fraction C1, comprising the following steps: S1: Biomass raw materials are stripped under acid catalysis to produce platform compound A, and then hydrolyzed to produce platform compound B; S2: condensing the platform compound A and the platform compound B under alkaline conditions to obtain an oxygenated aviation fuel precursor; Furanaldehyde solution and fructose acid solution are condensed in an alkaline environment to extend the carbon chain and obtain an oxygenated aviation fuel precursor.

[0007] S3: Hydrodeoxygenating the oxygenated aviation fuel precursor to obtain a hydrodeoxygenated product; then catalytically hydrocracking and isomerizing the hydrodeoxygenated product to obtain aviation fuel fraction C1; The oxygenated aviation fuel precursor is pre-hydrogenated using an M1 catalyst, wherein the M1 catalyst is a Ni-supported metal oxide; and the M2 catalyst is a Ni-supported acidic multi-level porous molecular sieve; Step 2: Preparation of aviation fuel fraction C2, comprising the following steps: S4: The remaining biomass after hydrolysis in step S1 is dehydrated, dried and granulated into biomass pellets, which are then gasified to produce synthesis gas; The gasification process includes high-temperature gasification of biomass particles to produce a crude synthesis gas containing CO2, CO and H2, which is then converted to adjust the hydrogen-carbon ratio and then desulfurized and purified to obtain clean gas (CO2+CO+H2).

[0008] More preferably, the biomass remaining after hydrolysis is pretreated before gasification treatment, including the following process: the biomass remaining after hydrolysis is dehydrated, dried and pressed into white biomass pellets with a moisture content of less than 10%; compared with the prior art that requires carbonizing the biomass into black pellets, energy consumption can be significantly reduced. Combined with the improvement of the process method of the present application, drying and pressing into white biomass pellets can meet the process requirements.

[0009] S5: generating a Fischer-Tropsch oil by Fischer-Tropsch synthesis of the synthesis gas; fractionating the Fischer-Tropsch oil into a light fraction oil below C16 and a heavy fraction oil above C16, wherein the heavy fraction oil above C16 is cracked to obtain a pyrolysis oil; and mixing the light fraction oil below C16 and the pyrolysis oil to obtain a Fischer-Tropsch mixed oil; S6: Depressing the pour point of the Fischer-Tropsch mixed oil by catalytic isomerization to obtain aviation fuel fraction C2; Step 3: Preparation of biomass aviation fuel, including the following processes: S7: mixing the aviation fuel fraction C1 and the aviation fuel fraction C2 obtained in step 1 and step 2 to obtain aviation fuel mixed crude oil C; S8: Fractionating the aviation fuel mixture with crude oil C to obtain final biomass aviation fuel and liquefied natural gas. It should be noted that the fractionation mentioned in the above steps can be performed using conventional fractionation methods, and this application does not involve any improvement to the fractionation method.

[0010] Based on the above technical solution, the preparation of platform compound A and platform compound B in step S1 includes the following process: wherein platform compound A is a furan aldehyde aqueous solution, and platform compound B is a fructose acid aqueous solution; S11: stripping; biomass raw materials are heated at 160-180℃ and 0.8MPa pressure in SO4 2- / M x O y In a solid acid environment, a mixture of furan aldehyde and formic acid is prepared by dehydration through a steam stripping process; then the furan aldehyde aqueous solution is separated by cooling; S12: hydrolysis; the stripped biomass and the aqueous solution from which the furan aldehyde solution has been extracted are further hydrolyzed under a solid acidic environment for 2-4 hours, and distilled to obtain an aqueous solution of fructose acid having a content of 1-2%.

[0011] In this application, stripping and hydrolysis are used to obtain platform compound A and platform compound B respectively. At the same time, solid acid is used in the stripping and hydrolysis process, which reduces the amount of wastewater, reduces wastewater discharge, and reduces the high requirements of production equipment on materials.

[0012] The removal of trace elements in the biomass after steam stripping and hydrolysis reduces equipment corrosion, reduces equipment manufacturing difficulty, and also reduces coking during the biomass gasification process, reducing the difficulty of biomass gasification. Preferably, the concentration of the furan aldehyde solution is 90%; More preferably, the platform compound in the present application does not require distillation and purification, thereby reducing energy consumption.

[0013] Based on the above technical solution, the preparation of the oxygenated aviation fuel precursor includes the following steps: The furanaldehyde aqueous solution and the fructose acid aqueous solution are subjected to condensation reaction under normal pressure, temperature of 55-75° C., and pH ≥ 8; After the condensation reaction is completed, the reaction is quenched in an ice-water bath, and the oxygenated aviation fuel precursor is obtained after centrifugation, washing, and drying.

[0014] Based on the above technical solution, the treatment of the oxygenated aviation fuel precursor in step S3 includes the following processes: S31: Hydrodeoxygenation product: The oxygenated jet fuel precursor is dissolved and mixed with methanol solvent in a mixer; then, along with hydrogen, it is propelled into a vaporizer for preheating before flowing into a hydrogenation reactor. The M1 catalyst saturates the C=C and C=O in the oxygenated jet fuel precursor to produce a hydrodeoxygenation product. S32: Gas-liquid phase separation; the material after the hydrogenation reaction is completed enters the first separator, where it is condensed and the gas and liquid phases are separated; the hydrogen is separated, purified, and pressurized before being recycled and fed into the hydrocracking and isomerization reactors for hydrogen replenishment, and the liquid hydrodeoxygenation product is collected and fed into the isomerization reactor; S33: Hydroisomerization reaction; the liquid-phase hydrodeoxygenation product flows to the hydrocracking and isomerization reactor, where it undergoes hydrocracking and isomerization degassing treatment under the action of the M2 catalyst; S34: Gas-liquid phase separation; the material after the hydroisomerization reaction is completed enters the second separator, where it is condensed and the gas and liquid phases are separated; the hydrogen is separated, purified, and pressurized before being recycled and entering the hydrodeoxygenation and hydroisomerization reactors for hydrogen replenishment, while the liquid paraffin flows into the third separator; S35: separation of product C1; the solvent and product are separated in the third separator, the vaporized solvent is condensed and liquefied by the condenser and then enters the mixer of step S31 for recycling, and the liquid phase material flowing out of the third separator is the aviation fuel fraction C1.

[0015] Based on the above technical solution, the gasification treatment in step S4 includes the following processes: S41: The remaining biomass after hydrolysis is centrifugally dehydrated, dried, compressed and granulated into biomass residue pellets. The moisture content is required to be less than 15% and the Hardgrove grinding coefficient is greater than 80. S42: The biomass residue particles are first ground in a grinder and then gasified into a gasification bed using high-pressure CO2 as a carrier gas to produce a crude synthesis gas containing CO, CO2 and H2, wherein the gasification pressure is 40-50 MPa and the temperature is 1000-1300°C; S43: The crude syngas is converted and hydrogenated to adjust the hydrogen-to-carbon ratio of the syngas, so that the volume ratio of H2 / CO in the syngas composition is 1.5-3 / 1. The crude syngas with adjusted hydrogen-to-carbon ratio is desulfurized and purified to produce purified syngas containing CO, CO2, and H2. The biomass residue particles are ground into a fine powder of 200-800 μm.

[0016] In this application, the biomass residue particles are gasified. Compared with the direct use of biomass raw materials for treatment, the structure of cellulose and lignin in the biomass is destroyed, and the problem of difficult grinding of the biomass raw materials themselves is eliminated. Before gasification, there is no need to bake and carbonize them into black particles as in the existing technology, but only needs to be dried and pressed into white particles, which reduces the problems of high energy consumption and carbon loss and is more conducive to the gasification of biomass-based raw materials. At the same time, it also solves the problems of difficult treatment of traditional biomass residue waste and high waste emissions, fully utilizes the carbon element in the biomass, improves the carbon conversion rate and utilization rate, and increases the production of aviation fuel per unit biomass.

[0017] Based on the above technical solution, the preparation of the Fischer-Tropsch mixed oil in step S5 includes the following processes: S51: Preparation of Fischer-Tropsch oil B1; using M3 catalyst in the first Fischer-Tropsch synthesis reactor at a temperature of 170-250°C, a synthesis gas partial pressure of 2.0-4.0 MPa, and a volume space velocity of 500-2500 h -1 The volume ratio of the recycled gas to the purified synthesis gas is 1:1-5:1, and Fischer-Tropsch oil B1 is generated; wherein the Fischer-Tropsch oil B1 is mainly alkanes; after the reaction is completed, the material enters the gas-liquid separator to separate the gas phase and the liquid phase material, the gas phase enters the second Fischer-Tropsch synthesis reactor in series, and the liquid phase alkanes flow into the fractionation tower; S52: Preparation of Fischer-Tropsch oil B2; using M4 catalyst to purify the unreacted syngas in the second Fischer-Tropsch synthesis reactor at a temperature of 170-250°C, a syngas partial pressure of 2.0-4.0 MPa, and a volume space velocity of 500-2500 h -1 , generating Fischer-Tropsch oil B2; wherein Fischer-Tropsch oil B2 is mainly aromatic hydrocarbons and some alkanes; after the reaction is completed, the material enters the gas-liquid separator to separate the gas phase and liquid phase materials, the gas phase is purified and enters the first Fischer-Tropsch reactor with the fresh purified synthesis gas, and the liquid phase aromatic hydrocarbons flow into the fractionation tower; S53: Fischer-Tropsch oil fractionation; the liquid alkanes in step S51 and the liquid aromatics in step S52 are mixed and fractionated in a fractionating tower to obtain a light fraction of alkanes and aromatics below C16 and a heavy fraction of aromatics above C16; specifically, the fraction below 300°C is the light fraction, and the fraction above 300°C is the heavy fraction.

[0018] S54: Heavy fraction cracking; the heavy fraction of aromatic hydrocarbons above C16 enters the cracking kettle and is cracked using M5 catalyst to produce cracking oil at a temperature of 250-310°C and a pressure of 5 MPa; S55: The C16 and lower alkyl aromatic light fractions in step S53 and the pyrolysis oil in step S54 are mixed to obtain a Fischer-Tropsch mixed oil.

[0019] In the present application, CO2 does not need to be separated in the gasification synthesis. After the Fischer-Tropsch synthesis of alkanes, the gas after gas-liquid separation does not need to be purified. Aromatics can be directly synthesized in series with the Fischer-Tropsch synthesis, and the mixture is mixed to form full-fraction aviation fuel. The operation process is more convenient and effective.

[0020] Based on the above technical solution, step S6 includes the following process: The Fischer-Tropsch mixed oil obtained in step S5 is fed into a hydroisomerization kettle and subjected to hydroisomerization using an M6 catalyst at a temperature of 250-310° C. and a pressure of 5 MPa to obtain aviation fuel C2.

[0021] Based on the above technical solution, the M1 catalyst is a Ni-supported metal oxide; the M2 catalyst is a Ni-supported acidic multi-level porous molecular sieve.

[0022] Based on the above technical solution, the M3 catalyst is a cobalt-based catalyst, Co-Mn / ZrO2 type catalyst; the M4 catalyst is ZnZrO x and HZSM-5 coupled catalyst; the M5 catalyst is formed by solid-phase calcination of a mixture of (NH4)2SO4 and ZrOCl2·8H2O.

[0023] Based on the above technical solution, the M6 ​​catalyst is made of an amorphous silica-alumina carrier loaded with one or more noble metals in Group VIII.

[0024] The beneficial effects of the technical solution provided by the present invention are: This application provides a process for preparing sustainable aviation fuel based on biomass raw materials. Using biomass raw materials as a basis is more conducive to achieving carbon emission reduction, reducing waste emissions, improving carbon conversion rates, and lowering energy consumption during the preparation process. Specifically, during the preparation of the platform compound, solid acid is used, which reduces wastewater volume, lowers the material requirements of production equipment, and eliminates the need for distillation and purification, thereby reducing energy consumption. The residual biomass after stripping and hydrolysis is recycled, avoiding waste residue emissions, achieving waste recycling, and fully utilizing the carbon element in the biomass. This also effectively addresses the difficulties of grinding traditional biomass raw materials and the low carbon conversion rates. It also reduces coking during the direct gasification of biomass raw materials, making biogasification easier and reducing energy consumption.

[0025] The biomass aviation fuel prepared by the above-mentioned improved preparation method has a more complete fraction than the current aviation fuel prepared from biomass, is comparable to the fraction of existing petrochemical-based aviation fuel, and has very excellent practical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of the preparation method of the present invention; DETAILED DESCRIPTION The following will be combined with the contents of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. The terms used in this specification are intended only to describe specific embodiments and are not intended to limit the present invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the listed items. It should be understood that, unless otherwise specified, the various raw materials in the present invention may be commercially available.

[0028] Biomass is used as raw material in this application. Due to the large variety of biomass types and differences in cellulose content, moisture content, etc., corn stalks are used as raw materials for biomass in the following embodiments.

[0029] The present application provides a process for preparing sustainable aviation fuel based on biomass raw materials, comprising the following steps: First, multiple batches of experiments are conducted to produce aviation fuel fraction C1. Then, the remaining biomass from the experiments is collected, dried and compressed into biomass pellets. The biomass pellets are evenly divided and ground into powder. Then, aviation fuel fraction C2 is produced in equal batches. Aviation fuel fractions C1 and C2 are then mixed and distilled to obtain aviation fuel.

[0030] Specifically, the experimental steps for the platform compounds furanaldehyde and fructose acid are as follows: corn stalks are cut into 1-3 cm long biomass blocks, steam at 160-180℃ is passed through, and SO4 2- / M x O y The crude furan aldehyde solution is obtained by steam stripping under a solid acid environment, and the steam stripping liquid is collected. The crude furan aldehyde solution is cooled, separated and separated to obtain furan aldehyde with a content of 90% and an aqueous solution. The aqueous solution is refluxed into the reactor and hydrolyzed at 160-180°C and 0.8 MPa for 2-4 hours. The biomass is cooled and filtered to obtain the remaining biomass for later use. The filtrate contains 1-2% fructose acid. Condensation experimental steps: Mix a 90% furan aldehyde solution and a 1-2% fructose acid filtrate, add ammonia water to adjust the pH value, stir the reaction, control the temperature at 50-70°C, condense the carbon chain to lengthen, form a suspension, cool and separate to obtain a solid powder, and dry to obtain the aviation fuel precursor condensate; Preparation of aviation fuel fraction C1: The condensation product is dissolved in methanol, hydrogenated at a high temperature of 250-320°C to saturate C=O and C=C bonds, deoxygenated, and refined at a temperature of 320-350°C to obtain isoparaffin products.

[0031] Preparation of biomass pellets: The remaining biomass after hydrolysis is filtered and dehydrated, dried in a dryer, and the moisture content is controlled within 10%. It is then compressed to form biomass pellets.

[0032] Biomass gasification: After the biomass particles are ground into powder, they are fed into the gasifier, oxygen is introduced into the furnace, the gasification temperature is controlled, the gasification synthesis gas is collected, and the content of CO, CO2 and H2 in the synthesis gas is tested.

[0033] A mixture of CO, CO2, and H2 is passed into the first reactor to maintain a certain carbon-hydrogen ratio and a fixed CO and CO2 content to produce alkane substance B1. The unreacted gas is passed into the second reactor to continue the reaction to produce aromatic hydrocarbons B2. Collect B1 and B2, mix them together, distill, collect the fraction below 280℃ as the light fraction, and crack the remaining hydrocarbons at 250-310℃ to obtain cracking products; The cracking products and light fractions are mixed together and hydrogenated at 320-350℃ to produce aviation fuel distillate C2; The aviation fuel fraction C2 is distilled and the fraction with a temperature of 150-280°C is used to obtain aviation fuel with a high aromatic content; Full fraction aviation fuel can be obtained by mixing aviation fuel with high aromatic content and aviation fuel oil obtained from aviation fuel fraction C1.

[0034] In the preparation of C1 fuel, the main factors affecting the yield are the temperature and time of stripping and hydrolysis. The cellulose and hemicellulose contents in the remaining biomass after hydrolysis can be detected to determine the degree of stripping and hydrolysis. Corn straw contains 33.2% cellulose, 30.4% hemicellulose, and 18.3% lignin. In combination with the above preparation process, the following table provides experimental parameters of multiple groups of examples:

[0035] Cross-over method: In Experimental Example 5, stripping at 170°C for 3 hours and hydrolysis at 170°C for 2 hours are the most suitable conditions in terms of reaction time and reaction temperature, that is, the optimal embodiment.

[0036] Example of preparing C2 fuel, the main factors affecting the yield are: gasification efficiency, catalytic selectivity of Fischer-Tropsch synthesis of aviation fuel.

[0037]

[0038] The cellulose content of the remaining biomass after stripping and hydrolysis is significantly reduced, the structure of the biomass is changed, the ash content and the chlorine content are significantly reduced, and the Hardgrove grinding coefficient is increased; the requirements for the corrosion resistance of the equipment are reduced, the grindability of the equipment is significantly improved, and the possibility of coking is reduced, making it suitable for coal gasification furnaces.

[0039] From the above analysis, it can be seen that Example 5, as a preferred embodiment, includes the following steps: The experimental steps of furanaldehyde and fructose acid were as follows: corn stalks were cut into 1-3 cm long biomass blocks, steamed at 170℃, and heated in SO4 2- / M x O y The crude furan aldehyde solution was obtained by steam stripping under solid acid for 3 hours, and the steam stripping liquid was collected. The crude furan aldehyde solution was cooled, separated and separated to obtain furan aldehyde with a content of 90% and an aqueous solution. The aqueous solution was refluxed into the reactor and hydrolyzed at 170°C and 0.8 MPa for 2 hours. The solution was cooled and filtered to obtain the remaining biomass for future use. The filtrate contained 1-2% fructose acid. Condensation experimental steps: Mix a 90% furan aldehyde solution and a 1-2% fructose acid filtrate, add ammonia to adjust the pH, and stir the reaction. The temperature is controlled at 60°C. The carbon chain is lengthened by condensation to form a suspension. Cool and separate to obtain a solid powder, which is then dried to obtain the aviation fuel precursor condensate. Preparation of aviation fuel fraction C1: The condensation product is dissolved in methanol, hydrogenated at 280°C to saturate C=O and C=C bonds, deoxygenated, and refined at 300°C to obtain the isoparaffin product. Preparation of biomass pellets: After hydrolysis, the remaining biomass is filtered and dehydrated, dried in a dryer to control the moisture content to less than 10%, and then compressed to form biomass white pellets.

[0040] Biomass gasification: After grinding, biomass pellets are fed into a gasifier. Oxygen is introduced into the furnace, the gasification temperature is controlled, and the gasification syngas is collected and tested for CO, CO2, and H2 content. A mixture of CO, CO2, and H2 is passed into reactor one, maintaining a constant carbon-hydrogen ratio and constant CO and CO2 content, to produce alkane B1. Unreacted gas is fed into the second reactor to continue the reaction and produce aromatics B2. Collect B1 and B2, mix them together, distill, collect the fraction below 280℃ as the light fraction, and crack the remaining hydrocarbons at 300℃ to obtain cracking products; The cracking products and light fractions are mixed together and hydrogenated at 300°C to produce aviation fuel distillate C2; Experimental results and performance analysis Here are the results of an experimental parallel instance of this approach: Experiment 1 parallel experiment:

[0041] The biomass residue was dried and ground into 1825 g of biomass powder with a moisture content of 10%; Experiment 2 parallel experiment:

[0042] 50,000g of biomass produces 7,550g of product 1, alkane aviation fuel, and 4,450g of product 2, high aromatic aviation fuel. After mixing, 12,000g of full-fraction aviation fuel is obtained. Converted into 1 ton of aviation fuel, 4.2 tons of straw is consumed.

[0043] The components of the biomass aviation fuel prepared in the above preferred embodiment are detected as follows: Sample Information:

[0044] Test results:

[0045] The samples submitted for inspection were random samples from optimized parallel experiments. The test results showed that they met the standards for aviation fuel. The standards for aromatic content in the product performance were consistent with those for petrochemical-based aviation fuel, and they met the standards for full-fraction aviation fuel, so they could be used directly without blending.

[0046] The straw consumption per ton of jet fuel has dropped from the usual 8-10 tons to about 4.2 tons, improving the utilization rate of biomass carbon from 60% to more than 90%.

[0047] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be included within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate. In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A process for preparing sustainable aviation fuel based on biomass raw materials, characterized in that: The following steps are involved: Step 1: Preparation of aviation fuel fraction C1, The following steps are involved: S1: Biomass raw materials are stripped under acid catalysis to produce platform compound A, and then hydrolyzed to produce platform compound B; S2: condensing the platform compound A and the platform compound B under alkaline conditions to obtain an oxygenated aviation fuel precursor; S3: Hydrodeoxygenating the oxygenated aviation fuel precursor to obtain a hydrodeoxygenated product; then catalytically hydrocracking and isomerizing the hydrodeoxygenated product to obtain aviation fuel fraction C1; Step 2: Preparation of aviation fuel fraction C2, comprising the following steps: S4: gasifying the remaining biomass after hydrolysis in step S1 to obtain synthesis gas; S5: generating a Fischer-Tropsch oil by Fischer-Tropsch synthesis of the synthesis gas; fractionating the Fischer-Tropsch oil into a light fraction oil below C16 and a heavy fraction oil above C16, wherein the heavy fraction oil above C16 is cracked to obtain a pyrolysis oil; and mixing the light fraction oil below C16 and the pyrolysis oil to obtain a Fischer-Tropsch mixed oil; S6: Depressing the pour point of the Fischer-Tropsch mixed oil by catalytic isomerization to obtain aviation fuel fraction C2; Step 3: Preparation of biomass aviation fuel, including the following processes: S7: mixing the aviation fuel fraction C1 and the aviation fuel fraction C2 obtained in step 1 and step 2 to obtain aviation fuel mixed crude oil C; S8: Fractionating the aviation fuel mixed crude oil C to obtain final biomass aviation fuel and liquefied natural gas.

2. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: The preparation of platform compound A and platform compound B in step S1 includes the following process: wherein platform compound A is a furan aldehyde aqueous solution, and platform compound B is a fructose acid aqueous solution; S11: stripping; Biomass raw materials are heated at 160-180℃ and 0.8MPa pressure in SO4 2- / M x O y In a solid acid environment, a mixture of furan aldehyde and formic acid is prepared by dehydration through a steam stripping process; then the furan aldehyde aqueous solution is separated by cooling; S12: hydrolysis; the stripped biomass and the aqueous solution from which the furan aldehyde solution has been extracted are further hydrolyzed under a solid acidic environment for 2-4 hours, and distilled to obtain an aqueous solution of fructose acid having a content of 1-2%.

3. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: The preparation of the oxygenated aviation fuel precursor includes the following steps: The furanaldehyde aqueous solution and the fructose acid aqueous solution are subjected to condensation reaction under normal pressure, temperature of 55-75° C., and pH ≥ 8; After the condensation reaction is completed, the reaction is quenched in an ice-water bath, and the oxygenated aviation fuel precursor is obtained after centrifugation, washing, and drying.

4. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: The treatment of the oxygenated aviation fuel precursor in step S3 includes the following processes: S31: Hydrodeoxygenation product: The oxygenated jet fuel precursor is dissolved and mixed with methanol solvent in a mixer; then, along with hydrogen, it is propelled into a vaporizer for preheating before flowing into a hydrogenation reactor. The M1 catalyst saturates the C=C and C=O in the oxygenated jet fuel precursor to produce a hydrodeoxygenation product. S32: Gas-liquid phase separation: After the hydrogenation reaction is completed, the material enters the first separator, and the gas phase and liquid phase are separated after condensation; The hydrogen is separated, purified and pressurized before being recycled and fed into the hydrocracking and isomerization reactors for hydrogen replenishment. The liquid hydrodeoxygenation product is collected and fed into the isomerization reactor. S33: Hydroisomerization reaction; The liquid phase hydrodeoxygenation product flows to the hydrocracking and isomerization reactor, where it undergoes hydrocracking and isomerization degassing treatment under the action of M2 catalyst; S34: gas-liquid phase separation: the material after the hydroisomerization reaction is completed enters the second separator, and the gas phase and liquid phase are separated after condensation; The hydrogen is separated, purified and pressurized before being recycled and fed into the hydrodeoxygenation and hydroisomerization reactors for hydrogen replenishment, while the liquid alkane flows into the third separator. S35: separation of product C1; the solvent and product are separated in the third separator, the vaporized solvent is condensed and liquefied by the condenser and then enters the mixer of step S31 for recycling, and the liquid phase material flowing out of the third separator is the aviation fuel fraction C1.

5. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: In the gasification process of step S4, The following processes are included: S41: The remaining biomass after hydrolysis is centrifugally dehydrated, dried, and compressed into biomass residue pellets. The moisture content is required to be less than 15%, and the Hardgrove grinding coefficient is greater than 80. S42: The biomass residue particles are first ground in a grinder and then gasified into a gasification bed using high-pressure CO2 as a carrier gas to produce a crude synthesis gas containing CO, CO2 and H2, wherein the gasification pressure is 40-50 MPa and the temperature is 1000-1300°C; S43: The crude synthesis gas is converted and hydrogenated to adjust the hydrogen-carbon ratio of the synthesis gas, and the volume ratio of H2 / CO in the synthesis gas composition is 1.5-3 / 1; the crude synthesis gas after the hydrogen-carbon ratio is adjusted is desulfurized and purified to become a purified synthesis gas containing CO, CO2 and H2.

6. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: The preparation of the Fischer-Tropsch mixed oil in step S5 includes the following processes: S51: Preparation of Fischer-Tropsch oil B1; using M3 catalyst in the first Fischer-Tropsch synthesis reactor at a temperature of 170-250°C, a synthesis gas partial pressure of 2.0-3.0 MPa, and a volume space velocity of 500-2500 h -1 The volume ratio of the recycled gas to the purified synthesis gas is 1:1-5:1, and Fischer-Tropsch oil B1 is generated; wherein the Fischer-Tropsch oil B1 is mainly alkanes; after the reaction is completed, the material enters the gas-liquid separator to separate the gas phase and the liquid phase material, the gas phase enters the second Fischer-Tropsch synthesis reactor in series, and the liquid phase alkanes flow into the fractionation tower; S52: Preparation of Fischer-Tropsch oil B2; using M4 catalyst to purify the unreacted synthesis gas in the second Fischer-Tropsch synthesis reactor at a temperature of 170-250°C, a synthesis gas partial pressure of 2.0-3.0 MPa, and a volume space velocity of 500-2500 h -1 , generating Fischer-Tropsch oil B2; wherein Fischer-Tropsch oil B2 is mainly aromatic hydrocarbons and some alkanes; after the reaction is completed, the material enters the gas-liquid separator to separate the gas phase and liquid phase materials, the gas phase is purified and enters the first Fischer-Tropsch reactor with the fresh purified synthesis gas, and the liquid phase aromatic hydrocarbons flow into the fractionation tower; S53: Fischer-Tropsch oil fractionation; the liquid alkanes in step S51 and the liquid aromatics in step S52 are mixed and fractionated in a fractionating tower to obtain a light fraction of alkanes and aromatics below C16 and a heavy fraction of aromatics above C16; S54: Heavy fraction cracking; the heavy fraction of aromatic hydrocarbons above C16 enters the cracking kettle and is cracked using M5 catalyst to produce cracking oil at a temperature of 250-310°C and a pressure of 5 MPa; S55: The C16 and lower alkyl aromatic light fractions in step S53 and the pyrolysis oil in step S54 are mixed to obtain a Fischer-Tropsch mixed oil.

7. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 1, characterized in that: Step S6 The following processes are included: The Fischer-Tropsch mixed oil obtained in step S5 is fed into a hydroisomerization kettle and subjected to hydroisomerization using an M6 catalyst at a temperature of 250-310° C. and a pressure of 5 MPa to obtain aviation fuel C2.

8. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 4, characterized in that: The M1 catalyst is a Ni-supported metal oxide; the M2 catalyst is a Ni-supported acidic multi-level pore molecular sieve.

9. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 6, characterized in that: The M3 catalyst is a cobalt-based catalyst, Co-Mn / ZrO2 type catalyst; the M4 catalyst is ZnZrO x and HZSM-5 coupled catalyst; the M5 catalyst is formed by solid-phase calcination of a mixture of (NH4)2SO4 and ZrOCl2·8H2O.

10. The process for preparing sustainable aviation fuel based on biomass raw materials according to claim 7, characterized in that: The M6 ​​catalyst is made of an amorphous silica-alumina carrier loaded with one or more noble metals in Group VIII.

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