Method for preparing green fuel by taking biomass as raw material and green fuel preparation system

Abstract

According to the method for preparing the green fuel with the biomass as the raw material and the green fuel preparation system, biomass utilization, hydrogen production through water electrolysis and methanol synthesis are coupled, the overall material and energy utilization efficiency can be improved, and the emission of carbon dioxide is reduced. The method comprises the following steps: (1) feeding biomass into a biomass gasification unit for gasification reaction to obtain crude synthesis gas; (2) feeding the crude synthesis gas into a gas purification unit for treatment; (3) feeding the purified synthesis gas into a decarburization unit for treatment to obtain carbon dioxide and decarburized synthesis gas; feeding carbon dioxide and hydrogen into a methanol synthesis unit to react to generate methanol; (4) mixing the decarbonized synthesis gas with hydrogen to adjust the hydrogen-carbon ratio of the synthesis gas, and feeding the adjusted synthesis gas into a Fischer-Tropsch synthesis unit to obtain a Fischer-Tropsch synthesis product; and (5) feeding hydrocarbons with more than C5 into a cracking isomerization unit to be in contact with hydrogen for hydro-conversion, and fractionating to obtain a gasoline component and an aviation kerosene component.

Description

TECHNICAL FIELD

[0001] The present application relates to a technology for preparing green fuel from biomass, in particular to a method for preparing green fuel from biomass and a green fuel preparation system. BACKGROUND

[0002] Under the global goal of carbon reduction, the international civil aviation industry is also gradually promoting the carbon reduction task. Bioaviation coal is the most important means of carbon reduction in the aviation industry. Compared with traditional petroleum-based aviation kerosene, bioaviation coal has the advantages of renewable raw material source, low impurity content, etc., and the total life cycle carbon dioxide emission can be reduced by more than 50%.

[0003] The current proven and ASTM standard recognized bioaviation coal synthesis technology routes mainly include three, which are ester hydrogenation process, gasification-Fischer-Tropsch synthesis process, and alcohol spray synthesis process. The biomass gasification-Fischer-Tropsch synthesis process has wide raw material adaptability, and can effectively convert agricultural waste and municipal solid waste within 50 kilometers, etc., which is a bioaviation coal production technology that is expected to be applied on a large scale in China.

[0004] CN114958446A proposes a system and method for preparing liquefied petroleum gas from biomass gasification. The system includes a pyrolysis reaction device, a gasification reaction device, a cyclone separation device, a heat recovery device, a cooling and impurity removal device, a condensation device, a tar removal device, a filtration device, a Fischer-Tropsch synthesis reaction device, and a rectification separation device connected in sequence. The technology realizes the conversion of biomass to low-carbon alkanes, but currently there is no green standard for liquefied petroleum gas from biomass, so the product price is relatively low, which has a certain impact on the technical economy.

[0005] CN108003939A proposes a micro-channel Fischer-Tropsch reactor that converts biomass gasification synthesis gas into hydrocarbons, and through hydrofining and hydroisomerization cracking, the hydrocarbons are prepared into jet fuel components. The hydrogen to carbon ratio of the purified gasification synthesis gas is about 1 (the ideal hydrogen to carbon ratio for Fischer-Tropsch synthesis is 2), and it contains 45.6% nitrogen and 11.5% carbon dioxide. This composition of gas will adversely affect the activity, life, and effective gas utilization rate of the catalyst. Moreover, the micro-channel reactor is difficult to process and replace the catalyst.

[0006] CN 102703107 A proposes a method for producing liquid hydrocarbons from biomass synthesis gas, which mixes the crude synthesis gas from biomass gasification with hydrogen-rich gas, adjusts the hydrogen to carbon ratio to 2-2.5, and then passes it into a Fischer-Tropsch reactor to produce hydrocarbons. The effective gas (hydrogen and carbon monoxide) after blending accounts for 90% of the total gas amount. The introduction of hydrogen-rich gas avoids the water-gas shift unit of the gasification synthesis gas, to some extent, simplifying the process flow.

[0007] CN101845319B proposes a process for producing wax and clean fuel oil from biomass as raw material, which vaporizes the biomass, then passes through tar reforming, gas purification, and synthesis gas reforming into a Fischer-Tropsch reactor, which adopts a three-stage reactor series process. The products are diesel, gasoline, and Fischer-Tropsch wax. This process has a long process flow, a complex reactor manufacturing process, and scattered products, and the yield is too low if oil products are the main products.

[0008] Currently, the problems of the technology for preparing aviation kerosene from biomass mainly include the following points: the total carbon utilization rate is low, the hydrogen-carbon ratio is usually adjusted by water-gas shift, a large amount of bio-based carbon is discharged in the form of carbon dioxide, and the carbon emission reduction effect is lost; the yield of aviation kerosene is low, the iron-based Fischer-Tropsch synthesis light component (such as the gasoline fraction) is high, and the yield of the aviation kerosene fraction is low; in addition, the cracking and isomerization process cannot meet the requirements, the oil products are excessively cracked, and the loss of the aviation kerosene fraction is high; the methane and other alkanes in the gasification process are difficult to utilize, which causes a large amount of Fischer-Tropsch synthesis reaction purge and reduces the synthesis efficiency; the hydrogen-carbon ratio of the synthesis gas is lower than 2, it is difficult to exert the highest performance of the Fischer-Tropsch synthesis catalyst, and the hydrogen-carbon ratio must be adjusted by water-gas shift. SUMMARY

[0009] In view of at least one deficiency in the prior art, the present application provides a method for preparing green fuel from biomass as raw material and a green fuel preparation system, which couples biomass utilization, water electrolysis to produce hydrogen, methanol synthesis, and aviation kerosene synthesis, is beneficial to improving the overall material and energy utilization efficiency, reducing the amount of carbon dioxide emissions, and is suitable for regional biomass utilization to produce high-value green fuel.

[0010] To achieve the purpose, the present application provides the following technical solutions:

[0011] The present application provides a method for preparing green fuel from biomass as raw material, which comprises the following steps:

[0012] (1) biomass is sent into a biomass gasification unit to contact a gasification agent and oxygen produced by an electrolytic water hydrogen production unit to perform a gasification reaction, to obtain crude synthesis gas;

[0013] (2) the crude synthesis gas is sent into a gas purification unit for treatment, to obtain purified synthesis gas;

[0014] (3) the purified synthesis gas is sent into a decarburization unit for treatment, to remove carbon dioxide in the purified synthesis gas, to obtain carbon dioxide and decarburized synthesis gas;

[0015] The carbon dioxide and hydrogen produced by the electrolytic water hydrogen production unit are sent into a methanol synthesis unit to react to generate methanol;

[0016] (4) mixing the hydrogen produced by the water electrolysis unit and the decarburized synthesis gas to adjust the hydrogen-carbon ratio of the synthesis gas, and feeding the adjusted synthesis gas into a Fischer-Tropsch synthesis unit to perform a Fischer-Tropsch synthesis reaction to obtain a Fischer-Tropsch synthesis product, and separating C5+ hydrocarbons in the Fischer-Tropsch synthesis product;

[0017] (5) feeding the C5+ hydrocarbons into a cracking and isomerization unit to perform a hydroconversion reaction with hydrogen produced by the water electrolysis unit, and performing a fractionation on the obtained product to obtain a C5-C7 gasoline component and a C8-16 aviation kerosene component.

[0018] The present application also provides a green fuel preparation system using biomass as a raw material for implementing the above method, and the preparation system comprises:

[0019] a water electrolysis unit for electrolyzing water to produce hydrogen and oxygen;

[0020] a biomass gasification unit for performing a gasification reaction on biomass with oxygen from the water electrolysis unit and a gasification agent to obtain a raw synthesis gas;

[0021] a gas purification unit for purifying the raw synthesis gas to obtain a purified synthesis gas;

[0022] a decarburization unit for removing carbon dioxide in the purified synthesis gas to obtain carbon dioxide and a decarburized synthesis gas;

[0023] a methanol synthesis unit for reacting carbon dioxide from the decarburization unit and part of hydrogen from the water electrolysis unit to generate methanol;

[0024] a Fischer-Tropsch synthesis unit, a synthesis gas inlet of the Fischer-Tropsch synthesis unit is connected with a decarburized synthesis gas outlet of the decarburization unit through a decarburized synthesis gas delivery pipeline, a hydrogen delivery pipeline of the water electrolysis unit is connected with the decarburized synthesis gas delivery pipeline to enable hydrogen to be introduced into the decarburized synthesis gas delivery pipeline; the Fischer-Tropsch synthesis unit is used to perform a Fischer-Tropsch synthesis reaction on the decarburized synthesis gas to obtain a Fischer-Tropsch synthesis product and separate C5+ hydrocarbons in the Fischer-Tropsch synthesis product;

[0025] a cracking and isomerization unit for performing a hydroconversion reaction on the C5+ hydrocarbons and part of hydrogen from the water electrolysis unit, and performing a fractionation on the obtained product to obtain a C5-C7 gasoline component, a C8-16 aviation kerosene component, and a tail oil fraction above 300℃.

[0026] The technical solution provided by the present application has the following beneficial effects:

[0027] The present application couples biomass utilization with water electrolysis hydrogen production, carbon dioxide methanol synthesis, and aviation fuel synthesis, improves overall material and energy utilization efficiency, and reduces carbon dioxide emissions. The present application is suitable for regional biomass and green electricity utilization, and produces high value-added green fuels, including bioaviation fuel, green gasoline, and green methanol. In the preferred embodiment, the preferred gasification furnace operating conditions, and / or the preferred hydrogenation conversion reaction conditions, and / or the preferred hydrogenation cracking isomerization catalyst, and / or the preferred Fischer-Tropsch synthesis reaction conditions, and / or the preferred Fischer-Tropsch synthesis catalyst are used to further improve the yield of aviation kerosene. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 FIG. 1 is a schematic diagram of a green fuel production system according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present application, the present application will be further described below in conjunction with examples. It should be understood that the following examples are only for better understanding of the present application, and do not mean that the present application is limited to the following examples.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. The terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance.

[0031] In the description of the present application, it should be noted that unless otherwise explicitly defined and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be connected inside two components. For those skilled in the art, the above belongs to the specific meaning in the present application can be understood according to the specific circumstances.

[0032] The present application provides a method for preparing green fuel from biomass, comprising the following steps:

[0033] (1) biomass is sent into a biomass gasification unit to contact with a gasification agent and oxygen produced by a water electrolysis hydrogen production unit to perform a gasification reaction, to obtain a crude synthesis gas;

[0034] (2) the crude synthesis gas is sent into a gas purification unit for treatment, to obtain a purified synthesis gas;

[0035] (3) the purified synthesis gas is sent into a decarburization unit for treatment, to remove carbon dioxide in the purified synthesis gas, to obtain carbon dioxide and decarburized synthesis gas;

[0036] The carbon dioxide and hydrogen produced by the water electrolysis unit are sent to a methanol synthesis unit to produce methanol;

[0037] (4) The decarbonated synthesis gas and hydrogen produced by the water electrolysis unit are mixed to adjust the hydrogen-carbon ratio of the synthesis gas, and the adjusted synthesis gas is sent to a Fischer-Tropsch synthesis unit to perform a Fischer-Tropsch synthesis reaction to obtain a Fischer-Tropsch synthesis product, and C5+ hydrocarbons in the Fischer-Tropsch synthesis product are separated;

[0038] (5) The C5+ hydrocarbons are sent to a cracking and isomerization unit to contact hydrogen produced by the water electrolysis unit to perform a hydroconversion, and the obtained product is fractionated to obtain a C5-C7 gasoline component and a C8-16 aviation kerosene component.

[0039] Further, the water electrolysis unit is powered by green electricity, and the hydrogen obtained by the water electrolysis unit is green hydrogen.

[0040] The method of the present application couples biomass utilization with hydrogen production by water electrolysis and methanol production from carbon dioxide, improves overall material and energy utilization efficiency, reduces carbon dioxide emissions, and is suitable for regional biomass and green electricity utilization to produce high-value green fuels, including bioaviation kerosene, green gasoline, and green methanol.

[0041] The raw material in the cracking and isomerization unit is C5+ hydrocarbons obtained from the Fischer-Tropsch synthesis unit and hydrogen obtained from the water electrolysis unit. In a preferred embodiment, in step (5), the reaction conditions for the hydroconversion in the cracking and isomerization reactor of the cracking and isomerization unit include: a temperature of 320-370°C; a pressure of 3-8.2 MPa; a liquid feed volume space velocity (LHSV) of 0.5-1.5 h -1 ; and a hydrogen-oil volume ratio of 500-1200:1.

[0042] More preferably, in step (5), the reaction conditions for the hydroconversion in the cracking and isomerization reactor of the cracking and isomerization unit include: a temperature of 320-360°C; a pressure of 3-8 MPa, more preferably 6-8 MPa; a liquid feed volume space velocity of 0.5-1.5 h -1; hydrogen to oil volume ratio is 500-1000:1; the obtained oil product has further improved aviation kerosene proportion under the preferred cracking isomerization reaction conditions in the method of the present application. Further preferably, the hydrocracking isomerization catalyst in the cracking isomerization reactor comprises a carrier and a noble metal supported on the carrier, the carrier comprises alumina, amorphous silica-alumina and ZSM-48 in a mass ratio of 30-60%:20-50%:10-40%, and the noble metal comprises Pt and / or Pd, the mass content of the noble metal in the hydrocracking isomerization catalyst is 0.2-0.5%. The inventors of the present application found that, in the cracking isomerization unit, under the preferred hydrocracking isomerization catalyst and the above-mentioned preferred hydroconversion reaction conditions, the aviation kerosene proportion in the obtained oil product can be further significantly improved, and the aviation kerosene yield can be improved. The above-mentioned hydrocracking isomerization catalyst can be prepared by using the existing process, for example, the carrier is prepared by mixing ZSM-48, alumina and amorphous silica-alumina and then extruding, the noble metal component is supported on the carrier by impregnation method (for example, equal volume impregnation), the soluble salt of the corresponding noble metal (for example, nitrate, etc., taking platinum as an example, such as chloroplatinic acid, dichlorotetrakisammonium platinum, ammonium platinum nitrate, etc.) is prepared into an impregnation solution for impregnation, and then the catalyst is obtained by drying and calcination. ZSM-48 can be obtained by using a commercial product or by using the existing process, for example, by hydrothermal synthesis.

[0043] In step (5), the cracking isomerization unit uses hydrogen produced by the electrolytic water hydrogen production unit, for example, green hydrogen, to perform hydroconversion on the hydrocarbons with a carbon number of 5 or more obtained from the Fischer-Tropsch synthesis unit. In some examples, the single-pass conversion rate is 50-60%, and after fractionation, for example, after atmospheric pressure distillation, C5-C7 gasoline components (distillation range 63-205°C), C8-16 aviation kerosene components (distillation range 205-300°C) and tail oil fractions with a distillation range ≥300°C are obtained. Preferably, the tail oil fraction is recycled to the cracking isomerization unit to continue to participate in the hydroconversion.

[0044] In some examples, the C5-C7 gasoline components (green gasoline) and the C8-16 aviation kerosene components (green aviation kerosene) obtained by the cracking isomerization unit have a green gasoline weight ratio of 10-40% and a green aviation kerosene weight ratio of 60-90%.

[0045] In a preferred embodiment, in step (1), the gasification furnace of the biomass gasification unit is a fluidized bed gasification furnace; in step (1), the pressure of the gasification furnace is 0.1-3 MPa, and the gasification section temperature is 700-1200°C; more preferably, the pressure of the gasification furnace is 0.8-3 MPa, and the gasification section temperature is 800-1000°C, which is beneficial to inhibit methane selectivity and further improve the yield of the obtained Fischer-Tropsch synthesis wax oil, thereby improving the aviation kerosene yield.

[0046] In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented. -1 In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented. Figure 1 In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented.

[0047] In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented. -1 In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented.

[0048] In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented. Figure 1 In the preferred embodiment, in step (4), the Fischer-Tropsch synthesis reaction is carried out in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor; the pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250°C, the volume space velocity of the feed gas is 400-1550 h-1, and the circulation ratio is 2-5; wherein the feed gas refers to the decarburized synthesis gas fed through the decarburized synthesis gas delivery pipeline and the hydrogen gas supplemented.

[0049] Specifically, the Fischer-Tropsch synthesis unit comprises a Fischer-Tropsch synthesis reactor and a Fischer-Tropsch product separation device, wherein the Fischer-Tropsch product separation device is used to separate the Fischer-Tropsch synthesis product obtained in the Fischer-Tropsch synthesis reactor to separate C5+ hydrocarbons, and the Fischer-Tropsch product separation device can use devices and processes known in the art to perform the above separation, which is not particularly limited; for example, the Fischer-Tropsch product separation device mainly comprises a first-stage gas-liquid separator, a second-stage gas-liquid separator, and a third-stage gas-liquid separator connected in series, and the heavy wax, heavy oil, and light oil separated through the three-stage separators are mixed to be the product of the unit, and the components are C5+ hydrocarbons.

[0050] Preferably, in step (4), the mass fraction of C20+ hydrocarbons in the C5+ hydrocarbons separated from the Fischer-Tropsch synthesis product is not less than 60%, preferably not less than 70%.

[0051] In a more preferred embodiment, the preferred gasification furnace operating conditions are used in step (1), the preferred hydrogenation conversion reaction conditions and the preferred hydrocracking isomerization catalyst are used in the cracking isomerization reactor in step (5), and the preferred Fischer-Tropsch synthesis reaction conditions and the preferred Fischer-Tropsch synthesis catalyst are used in the Fischer-Tropsch synthesis reactor in step (4), so that the oil product prepared by the preferred method using biomass as the raw material has a significantly higher proportion of aviation kerosene, which is beneficial to obtain a more excellent aviation kerosene yield.

[0052] Preferably, the gasification agent in step (1) is steam, preferably the by-product steam in the Fischer-Tropsch synthesis unit in step (4), so as to effectively utilize the by-product steam in the system; for example, the superheated steam produced by heating the by-product steam in the drum of the Fischer-Tropsch synthesis unit by a boiler is used as the gasification agent.

[0053] The purge gas produced in the Fischer-Tropsch synthesis unit contains hydrogen, carbon monoxide, and low-carbon hydrocarbons (C4 or less), and preferably at least part of the purge gas in the Fischer-Tropsch synthesis unit in step (4) and at least part of the purge gas in the cracking isomerization unit in step (5) are sent to the biomass gasification unit in step (1), and the hydrocarbon substances in the purge gas are converted into synthesis gas through a steam reforming reaction, and the purge gas not sent to the biomass gasification unit is purged.

[0054] Specifically, in step (2), the crude synthesis gas is purified by a gas purification unit, which can be performed by using conventional crude synthesis gas purification devices and processes in the art, and the dust, tar, sulfur components and the like contained in the crude synthesis gas are removed by the gas purification unit. The gas purification unit can use conventional devices with corresponding functions in the art, for example, it can include two-stage cyclone dust collectors for purifying the gas containing fly ash and gasification slag flowing out of the top of the gasifier, and bag dust collectors, spray water washing towers, electrostatic tar collectors, settling tanks and fine desulfurization tanks located downstream of the two-stage cyclone dust collectors, etc. Purifying the crude synthesis gas by the gas purification unit is a conventional technique in the art, and will not be described here.

[0055] Specifically, in step (3), the carbon dioxide gas in the purified synthesis gas obtained in step (2) is separated by a decarburization unit, and the carbon dioxide removal device and process known in the art can be used, which is not particularly limited, for example, the carbon dioxide adsorbent uses N-methyldiethanolamine (MDEA), modified MDEA, solid adsorption, lye adsorption or membrane separation, etc.

[0056] Preferably, in step (4), the hydrogen-to-carbon ratio of the adjusted synthesis gas is 1.9-2.1, which is adjusted by mixing the required amount of hydrogen produced in the electrolytic water hydrogen production unit into the decarburized synthesis gas.

[0057] In the present application, the biomass is, for example, a mixture of one or more of agricultural waste (including straw, rice husk, cotton stalks, etc.), forestry waste (scattered wood, branches, fruit shells, fruit pits, etc.), livestock waste (animal manure), and construction waste (wood boards, wood chips).

[0058] In some embodiments, in step (1), the biomass is pretreated before being fed into the biomass gasification unit, and the pretreatment includes drying and granulating the biomass in a pretreatment unit. The granulation process is preferably chopping or extrusion molding. Preferably, the moisture content of the pretreated biomass is < 25 wt%; preferably, the pretreated biomass is in the form of block-shaped, sheet-shaped or cylindrical-shaped molded particles, and the maximum length of the block-shaped or sheet-shaped particles is preferably 10-30 mm, and the maximum diameter or maximum length of the cylindrical-shaped particles is preferably 5-30 mm. The biomass particles enter the biomass gasification unit for gasification to obtain synthesis gas mainly composed of hydrogen and carbon monoxide.

[0059] The raw material of the methanol synthesis unit is carbon dioxide from the decarburization unit and hydrogen (preferably green hydrogen) produced by the water electrolysis unit, to obtain product methanol and a small amount of purge gas. In a preferred embodiment, in step (3), the reaction temperature in the methanol synthesis unit is 200-300°C, preferably 220-270°C; the pressure is 1.5-10 MPa, preferably 2-8 MPa; preferably, the composition of the catalyst used in the methanol synthesis unit includes 53-65 wt% CuO, 20-30 wt% ZnO and 5-15 wt% Al2O3, and also includes 0.1-2 wt% of an auxiliary agent, which is one or more of the oxides of Pt, La, Zr, Cd. The catalyst can be prepared by existing processes, for example, by co-precipitation of Cu salt, Zn salt, Al salt and auxiliary agent components (such as soluble nitrate salt, etc.), washing, drying, adding a lubricant, extruding and then calcining. Using the above catalyst and under the above process conditions, the carbon dioxide utilization rate is high; the above catalyst has strong heat resistance and hydrothermal resistance in the methanol synthesis reaction. Preferably, the volume ratio of the carbon dioxide introduced into the methanol synthesis unit to the hydrogen produced by the water electrolysis unit is 1:2.5-3.5, more preferably 1:2.9-3.1.

[0060] The present application also provides a green fuel preparation system for preparing green fuel from biomass, which is used to implement the above method, as shown in Figure 1 , the preparation system comprises:

[0061] a water electrolysis unit for electrolyzing water to produce hydrogen and oxygen;

[0062] a biomass gasification unit for contacting biomass with oxygen 8 from the water electrolysis unit and a gasification agent to perform a gasification reaction to obtain raw synthesis gas 2;

[0063] a gas purification unit for purifying the raw synthesis gas 2 to obtain purified synthesis gas 3;

[0064] a decarburization unit for removing carbon dioxide in the purified synthesis gas 3 to obtain carbon dioxide 9 and decarburized synthesis gas 4;

[0065] a methanol synthesis unit for reacting carbon dioxide 9 from the decarburization unit and part of the hydrogen from the water electrolysis unit to produce methanol 13, and also produce part of the purge gas 14;

[0066] a Fischer-Tropsch synthesis unit, the synthesis gas inlet of which is connected with the decarburized synthesis gas outlet of the decarburization unit through a decarburized synthesis gas conveying pipeline 4, the hydrogen conveying pipeline 19 of the water electrolysis unit and the decarburized synthesis gas conveying pipeline 4 are connected to enable hydrogen to be introduced into the decarburized synthesis gas conveying pipeline; the Fischer-Tropsch synthesis unit is used to make the decarburized synthesis gas undergo Fischer-Tropsch synthesis reaction to obtain Fischer-Tropsch synthesis products and separate C5+ hydrocarbons 5 from the Fischer-Tropsch synthesis products;

[0067] a cracking and isomerization unit, which is used to make the C5+ hydrocarbons 5 and part of the hydrogen from the water electrolysis unit contact to undergo hydroconversion and separate the products obtained by the hydroconversion to obtain C5-C7 gasoline components 6, C8-16 aviation kerosene components 7 and tail oil fractions above 300°C.

[0068] Preferably, the steam outlet of the Fischer-Tropsch synthesis unit is connected with the biomass gasification unit through a steam conveying pipeline 15, and the by-product steam in the Fischer-Tropsch synthesis unit is sent to the biomass gasification unit as a gasification agent; in particular, the steam is superheated water vapor produced after the by-product steam from the steam drum in the Fischer-Tropsch synthesis unit is heated by a boiler.

[0069] Preferably, the first purge gas output pipeline 16 of the Fischer-Tropsch synthesis unit and the second purge gas output pipeline 18 of the cracking and isomerization unit are respectively connected with the biomass gasification unit; so that at least part of the purge gas produced in the Fischer-Tropsch synthesis unit and at least part of the purge gas produced in the cracking and isomerization unit can be recycled to the biomass gasification unit to convert the hydrocarbon substances in the purge gas into synthesis gas; the first purge gas output pipeline 16 can also be connected with a purge branch 17 for discharging part of the purge gas.

[0070] In particular, the cracking and isomerization unit includes a cracking and isomerization reactor and a fractionation device, wherein the cracking and isomerization reactor is used to make the C5+ hydrocarbons and part of the hydrogen from the water electrolysis unit contact to undergo hydroconversion; the fractionation device is used to separate the products obtained by the hydroconversion to obtain C5-C7 gasoline components, C8-16 aviation kerosene components and tail oil fractions above 300°C. Preferably, the tail oil fraction outlet of the cracking and isomerization unit is connected with the hydroconversion raw material inlet of the cracking and isomerization unit through a tail oil fraction recycling pipeline (not shown in the figure) to recycle the tail oil fraction obtained by the fractionation in the cracking and isomerization unit to the cracking and isomerization reactor of the cracking and isomerization unit to continue to participate in the hydroconversion.

[0071] Preferably, the preparation system further comprises a pretreatment unit for pretreating the biomass, including drying and granulating, so as to provide the pretreated biomass 1 to the biomass gasification unit; the pretreatment unit dries and granulates the biomass to obtain the biomass for gasification with a desired water content and size. The pretreatment unit can adopt devices with corresponding functions known in the art, and there is no particular limitation thereto.

[0072] Specifically, the Fischer-Tropsch synthesis unit comprises a Fischer-Tropsch synthesis reactor and a Fischer-Tropsch product separation device, wherein the Fischer-Tropsch synthesis reactor is preferably a fixed bed reactor; the Fischer-Tropsch product separation device is used for separating C5+ hydrocarbons from Fischer-Tropsch synthesis products, and can adopt devices with corresponding functions known in the art, and there is no particular limitation thereto, for example, mainly comprising a primary gas-liquid separator, a secondary gas-liquid separator, and a tertiary gas-liquid separator connected in series; the heavy wax, heavy oil, and light oil separated through the tertiary gas-liquid separator are mixed to be the product of the unit, and the components are C5+ hydrocarbons.

[0073] Specifically, the hydrogen outlet of the water electrolysis unit is connected to the hydrogen delivery pipeline 19, the hydrogen delivery pipeline 19 is connected to the methanol synthesis unit through the first branch pipeline 11, connected to the cracking and isomerization unit through the second branch pipeline 12, and connected to the post-decarbonization synthesis gas delivery pipeline 4 through the third branch pipeline 10, so as to be able to introduce the hydrogen generated by the water electrolysis unit into the methanol synthesis unit and the cracking and isomerization unit as raw materials, and be able to mix the hydrogen into the post-decarbonization synthesis gas delivery pipeline to adjust the hydrogen-carbon ratio in the synthesis gas; specifically, a valve is arranged on each pipeline.

[0074] Further, the water electrolysis unit uses green electricity as the power source, and obtains green hydrogen through the water electrolysis unit.

[0075] For the description of the green fuel preparation system of the present application, reference can be made to the corresponding description of the devices in the method for preparing green fuel by using biomass as raw material, and no detailed description is given.

[0076] The processes, devices, elements, etc. involved in the present application are not particularly described, and can be performed by using conventional techniques in the art, and no detailed description is given.

[0077] Through the method and system of the present application, biomass can be converted into green fuel, and raw materials can be used in a high value way; biomass conversion is coupled with a green electricity and green hydrogen system and a methanol synthesis unit to improve material and energy utilization efficiency, improve the carbon emission reduction rate of green fuel, solve the pain points of green electricity and green hydrogen storage and transportation, can utilize green electricity and green hydrogen on site, and can also effectively utilize biomass such as agricultural and forestry waste and municipal waste; through the present application, the utilization path of carbon dioxide in biomass gasification gas is solved, the carbon utilization rate in the biomass conversion process is improved, and the hydrogen-carbon ratio after biomass gasification can be adjusted without water-gas shift.

[0078] The present application will be further described below by examples, but should not be understood as being limited to the present application.

[0079] In the examples, if the specific experimental steps or conditions are not specified, the conventional experimental steps or conditions can be used. If the reagents or instruments are not specified by the manufacturer, they are conventional products that can be obtained from the market.

[0080] The catalyst used in Example 1 is described as follows:

[0081] (1) In the cobalt-based Fischer-Tropsch synthesis catalyst in the Fischer-Tropsch synthesis reactor, the carrier is ZrO2 and TiO2 with a mass ratio of 15:85, and Co and Mn additives are loaded on the carrier, wherein the content of Co element is 28wt%, and the content of Mn element is 0.2wt%. The catalyst can be prepared by using the existing process. For reference, the catalyst used in Example 1 is prepared according to the following preparation steps:

[0082] The zirconium nitrate aqueous solution (concentration of 23wt%) and titanium tetrachloride aqueous solution (concentration of 20wt%) are mixed and stirred, and ammonia water (concentration of 15wt%) is continuously added until the precipitation no longer increases, the co-precipitate is filtered and washed, dried and calcined (calcination temperature is 520℃, calcination time is 4h) to obtain the carrier; the carrier is mixed with active metal components (Co(OH)2 and Mn(NO3)2) by dry method, then the molding agent (methyl cellulose, the amount is 5% of the total mass of raw materials) and ammonia water (concentration of 20wt%, the amount is 5% of the total mass of raw materials) are stirred uniformly, then extrusion molding, calcination (calcination temperature is 550℃, calcination time is 4h) to obtain the catalyst.

[0083] (2) In the hydrocracking isomerization catalyst in the cracking isomerization reactor, the carrier is Al2O3, ASA (amorphous silica-alumina) and ZSM-48 with a mass ratio of 50%:30%:20%, and noble metal Pt is loaded on the carrier, and the content of Pt in the catalyst is 0.2wt%. The catalyst can be prepared by using the existing process. For reference, the catalyst used in Example 1 is prepared according to the following preparation steps:

[0084] In the hydrocracking isomerization catalyst, the ZSM-48 molecular sieve is obtained by a hydrothermal synthesis method, the alumina and amorphous silica-alumina are commercially available, the ZSM-48 molecular sieve, the alumina and the amorphous silica-alumina are mixed according to the required mass ratio, and then extruded to obtain a carrier. The carrier is immersed in an aqueous chloroplatinic acid solution with a concentration of 0.2wt% by an equal-volume impregnation method, and then dried, calcined (calcination temperature is 550℃, calcination time is 6h) to obtain the catalyst. The steps of preparing the ZSM-48 molecular sieve by the hydrothermal synthesis method include: mixing corresponding amounts of silica sol, sodium aluminate aqueous solution, template agent (hexamethylene diamine) and sodium hydroxide aqueous solution according to the weight ratio H2O:hexamethylene diamine:Al2O3:NaOH:SiO2=30:0.02:0.01:0.09:1, crystallizing at 180-200℃ for 12h, drying, washing, and then calcining at 500℃ for 4h to obtain the molecular sieve.

[0085] (3) The composition (mass fraction) of the catalyst in the methanol synthesis unit is CuO 59.9%, ZnO 30% and Al2O3 10% and 0.1% La2O3. The catalyst can be prepared by using the existing process. For reference, the catalyst used in Example 1 is prepared according to the following preparation steps:

[0086] The catalyst is prepared by a coprecipitation method. 25wt% Cu(NO3)2 aqueous solution, 32wt% Zn(NO3)2 aqueous solution, 18wt% Al(NO3)3 aqueous solution and 1wt% La(NO3)3 aqueous solution are stirred and mixed, then heated to 60℃ and maintained; 5wt% Na2CO3 aqueous solution is continuously added to form a precipitate, and when the precipitate no longer increases, the stirring is stopped and aged for 12h; the precipitate is filtered, washed and dried, 5% of the total mass of the raw materials of graphite powder extrusion aid and 18wt% of water are added, and then extruded into cylindrical particles with a diameter of 0.4-0.8mm, and then calcined, the calcination temperature is 320℃, and the calcination time is 6h.

[0087] The following examples use the green fuel preparation system shown in Figure 1 The descriptions of the system can be referred to the foregoing, which will not be described one by one.

[0088] Example 1

[0089] The waste wood formed material (moisture content is 10wt%) with a diameter of 10mm and a length of 10-20mm is used as the biomass raw material to be gasified, and a pressurized pure oxygen fluidized bed gasification is adopted. In the fluidized bed gasification furnace, the gasification temperature is 900℃, and the pressure is 1.0MPa. The oxidant is pure oxygen from the water electrolysis water production unit. The gasification agent is water vapor, which is superheated steam generated after the boiler heating of the steam drum by-product steam from the Fischer-Tropsch synthesis unit. The mixture of pure oxygen and water vapor enters the gasification furnace. The gas containing fly ash and gasification slag flowing out of the top end of the gasification furnace is purified by the gas purification unit. Specifically, the gas containing fly ash and gasification slag first enters the two-stage cyclone dust collector, and the large particles with high carbon content are captured by the first-stage dust collector and re-enter the gasification furnace. Then, the fine fly ash captured by the second-stage dust collector enters the ash bucket and is discharged. The gas flowing out of the two-stage cyclone dust collector is treated by a bag filter, a spray water washing tower, an electrostatic tar collector, a settling tank and a fine desulfurization tank in sequence, so as to remove the dust, tar and sulfur-containing components in the gasification gas. The gas component information of the obtained purified synthesis gas is shown in Table 1.

[0090] The purified synthesis gas enters the decarburization unit, and the adsorbent is MDEA, which removes CO2 in the gas to obtain the decarburized synthesis gas. At this time, the hydrogen-carbon ratio of the synthesis gas is less than 1, which is not suitable for Fischer-Tropsch synthesis reaction. Green hydrogen is supplemented to the decarburized synthesis gas through the third branch pipe 10 to adjust the hydrogen-carbon ratio of the decarburized synthesis gas to 2. The decarburized synthesis gas with adjusted hydrogen-carbon ratio enters the Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit.

[0091] The Fischer-Tropsch synthesis reactor is a fixed bed reactor with a matching steam drum. The synthesis pressure is 3.5MPa, the temperature is 220℃, the decarburized synthesis gas conveying pipeline 4 is connected to the fixed bed reactor at a fresh gas space velocity of 700h -1 (That is, the feed gas space velocity), and the circulation ratio is 4. The Fischer-Tropsch synthesis reactor is filled with a cobalt-based Fischer-Tropsch synthesis catalyst. The carrier of the catalyst is ZrO2 and TiO2 with a mass ratio of 15:85. Co and Mn additives are loaded on the carrier, wherein the Co element content is 28wt%, and the Mn element content is 0.2wt%. The reaction data of the Fischer-Tropsch synthesis reactor are shown in Table 1.

[0092] The Fischer-Tropsch synthesis product obtained from the Fischer-Tropsch synthesis reactor is separated by a Fischer-Tropsch product separation device of the Fischer-Tropsch synthesis unit to obtain a liquid product, which is more than 92wt% of saturated alkanes, and the rest is olefins and a small amount of oxygen-containing compounds; from the hydrocarbon carbon number distribution, the liquid product is mainly hydrocarbons with carbon number of C5 or more, and the mass fraction of hydrocarbons with carbon number of C20 or more is 73%. The liquid product enters the cracking and isomerization reactor of the cracking and isomerization unit, and the hydrogen in the reactor is produced by the hydrogen production unit of electrolytic water, the hydrogen to oil volume ratio is 1000:1, the temperature is 350℃, the pressure is 7.5MPa, and the LHSV space velocity is 1h -1 The hydrogenation cracking and isomerization catalyst in the reactor is composed of Al2O3, ASA (amorphous silica-alumina) and ZSM-48 in a mass ratio of 50%:30%:20%, and the noble metal Pt is loaded on the carrier, and the content of Pt in the catalyst is 0.2wt%.

[0093] The raw oil wax has a single-pass conversion rate of 50%, and the obtained product is subjected to atmospheric and vacuum distillation to obtain C5-C7 gasoline, C8-C16 aviation kerosene and tail oil fraction above 300℃, wherein the tail oil fraction is recycled back to the cracking and isomerization reactor. In the obtained C5-C7 gasoline and C8-C16 aviation kerosene, the proportion of gasoline is 24wt%, and the proportion of aviation kerosene is 76wt%.

[0094] The carbon dioxide separated in the decarburization unit is mixed with the hydrogen produced by the electrolytic water hydrogen production unit at a volume ratio of 1:3.3, and then enters the methanol synthesis unit, and the reaction temperature is 246℃, the pressure is 8MPa, and the catalyst composition (mass fraction) is CuO 59.9%, ZnO 30% and Al2O3 10% and 0.1% La2O3.

[0095] In this embodiment, the consumption and output of the process system are shown in Table 1 below.

[0096] Example 2-3

[0097] Examples 2 and 3 are carried out according to Example 1, except that some reaction conditions are different, see Table 1 below. The results of Examples 2 and 3 are shown in Table 1.

[0098] Example 4

[0099] Example 1 is carried out, except that in the fluidized bed gasifier, the gasification temperature is 750℃, and the pressure is 0.2MPa.

[0100] Example 5

[0101] The procedure of Example 1 was followed except that the support of the Fischer-Tropsch synthesis catalyst in the Fischer-Tropsch synthesis reactor was ZrO2and TiO2in a mass ratio of 50:50, with Co and Mn promoters supported on the support, wherein the Co content was 30 wt% and the Mn content was 0.3 wt%.

[0102] Example 6

[0103] The procedure of Example 1 was followed except that in the Fischer-Tropsch synthesis reactor, the synthesis pressure was 1.8 MPa, the temperature was 195°C, and after decarburization, the synthesis gas was fed to the fixed bed reactor at a fresh gas space velocity of 1550 h -1 .

[0104] Example 7

[0105] The procedure of Example 1 was followed except that the support of the hydrocracking isomerization catalyst in the cracking isomerization reactor was alumina, amorphous silica-alumina and ZSM-5 in a mass ratio of 50:30:20.

[0106] Example 8

[0107] The procedure of Example 1 was followed except that in the cracking isomerization reactor, the temperature was 370°C, the pressure was 8.2 MPa, the LHSV space velocity was 1 h -1 , and the hydrogen to oil volume ratio was 1200:1.

[0108] Table 1 Reaction conditions and experimental results of each example

[0109]

[0110]

[0111] It is easily understood that the above examples are merely illustrative and are not meant to limit the present application. Other variations or modifications can be made on the basis of the above description by those of ordinary skill in the art. It is not necessary to exhaust all the embodiments. The obvious changes or modifications extending from the above still fall within the scope of the present application.

Claims

1. A method for producing green fuel from biomass, characterized by, The method comprises the following steps: (1) sending the biomass into a biomass gasification unit to contact with a gasification agent and oxygen produced by an electrolytic water hydrogen production unit to perform a gasification reaction, to obtain a crude synthesis gas; (2) sending the crude synthesis gas into a gas purification unit to perform a treatment, to obtain a purified synthesis gas; (3) sending the purified synthesis gas into a decarburization unit to perform a treatment, to remove carbon dioxide in the purified synthesis gas, to obtain carbon dioxide and a decarburized synthesis gas; sending the carbon dioxide and hydrogen produced by the electrolytic water hydrogen production unit into a methanol synthesis unit to perform a reaction to generate methanol; (4) mixing the decarburized synthesis gas and hydrogen produced by the electrolytic water hydrogen production unit to adjust a hydrogen-carbon ratio of the synthesis gas, and sending the adjusted synthesis gas into a Fischer-Tropsch synthesis unit to perform a Fischer-Tropsch synthesis reaction, to obtain a Fischer-Tropsch synthesis product, and separating C5+ hydrocarbons in the Fischer-Tropsch synthesis product; (5) sending the C5+ hydrocarbons into a cracking and isomerization unit to contact with hydrogen produced by the electrolytic water hydrogen production unit to perform a hydroconversion, and performing a fractionation on the obtained product to obtain a C5-C7 gasoline component and a C8-16 aviation kerosene component.

2. The method of claim 1, wherein, In step (5), the reaction conditions for the hydroconversion in the cracking isomerization reactor of the cracking isomerization unit include: a temperature of 320-370°C; a pressure of 3-8.2 MPa; a liquid feed volume space velocity of 0.5-1.5 h -1 -1; a hydrogen to oil volume ratio of 500-1200:1; Preferably, in step (5), the reaction conditions for the hydroconversion in the cracking isomerization reactor of the cracking isomerization unit include: a temperature of 320-360°C; a pressure of 3-8 MPa, more preferably 6-8 MPa; a liquid feed volume space velocity of 0.5-1.5 h -1 ; a hydrogen to oil volume ratio of 500-1000:1; Further preferably, the hydrocracking and isomerization catalyst in the cracking and isomerization reactor comprises a carrier and a noble metal supported on the carrier, the carrier comprises alumina, amorphous silica-alumina and ZSM-48 in a mass ratio of 30-60%:20-50%:10-40%, and the noble metal comprises Pt and / or Pd, and the mass content of the noble metal in the hydrocracking and isomerization catalyst is 0.2-0.5%.

3. The method according to claim 1 or 2, characterized in that, In step (1), the gasification furnace of the biomass gasification unit is a fluidized bed gasification furnace. In step (1), the pressure of the gasification furnace is 0.1-3 MPa, and the temperature of the gasification section is 700-1200℃. Preferably, the pressure of the gasification furnace is 0.8-3 MPa, and the temperature of the gasification section is 800-1000℃.

4. The method of claim 3, wherein, In step (4), the Fischer-Tropsch synthesis reaction is performed in a Fischer-Tropsch synthesis reactor of the Fischer-Tropsch synthesis unit, and the Fischer-Tropsch synthesis reactor is a fixed bed reactor. The pressure of the Fischer-Tropsch synthesis reaction is 1.8-4.0 MPa, the temperature is 195-250℃, the volume space velocity of the feed gas is 400-1550 h -1 , and the circulation ratio is 2-5. Preferably, the Fischer-Tropsch synthesis reaction is carried out at a pressure of 2.0 to 4.0 MPa; a temperature of 200 to 250°C, more preferably 205 to 240°C; a volume hourly space velocity of the feed gas of 400 to 1500 h -1 ; and a hydrogen to carbon monoxide ratio of 1.8 to 2.

2. Further preferably, the Fischer-Tropsch synthesis catalyst used in the Fischer-Tropsch synthesis reaction comprises a carrier, an active metal and an additive supported on the carrier, the carrier comprises ZrO2 and / or TiO2, the active metal comprises Co, and the additive comprises Mn and / or Pt; the content of the Co is 20-50%, preferably 25-40%, and the content of the additive is 0.1-3%, based on the mass of the Fischer-Tropsch synthesis catalyst; the mass content of the TiO2 in the carrier is 50-100%, preferably 60-100%, and more preferably 80-100%.

5. The method according to any one of claims 1 to 4, characterized in that, In step (4), the mass fraction of C20+ hydrocarbons in the C5+ hydrocarbons is not less than 60%, preferably not less than 70%.

6. The method according to any one of claims 1 to 5, characterized in that, In step (1), the gasification agent is steam, and the by-product steam in the Fischer-Tropsch synthesis unit in step (4) is preferably used. and / or, at least part of the off-gas from the Fischer-Tropsch synthesis unit in step (4) and at least part of the off-gas from the cracking and isomerization unit in step (5) are fed into the biomass gasification unit in step (1); and / or, in step (5), tail oil fraction with a distillation range ≥ 300℃ is also obtained through the fractionation, and the tail oil fraction is recycled to the cracking and isomerization unit to continue participating in the hydroconversion; and / or, in step (4), the hydrogen to carbon ratio of the adjusted synthesis gas is 1.9-2.1; and / or, the water electrolysis unit is powered by green electricity, and the hydrogen obtained through the water electrolysis unit is green hydrogen.

7. The method according to any one of claims 1 to 6, characterized in that, In step (1), the biomass is pretreated before being fed into the biomass gasification unit, and the pretreatment includes drying and granulating the biomass in a pretreatment unit, and the granulation process is preferably chopping or extrusion molding; Preferably, the moisture content of the pretreated biomass is < 25wt%; Preferably, the pretreated biomass is in the form of block-shaped, sheet-shaped or cylindrical-shaped granules, and the maximum length of the block-shaped or sheet-shaped granules is preferably 10-30mm, and the maximum diameter or maximum length of the cylindrical-shaped granules is preferably 5-30mm.

8. The method according to any one of claims 1 to 7, characterized in that, In step (3), the reaction temperature in the methanol synthesis unit is 200-300℃, preferably 220-270℃; and the pressure is 1.5-10MPa, preferably 2-8MPa; Preferably, the composition of the catalyst used in the methanol synthesis unit includes 53-65wt% CuO, 20-30wt% ZnO and 5-15wt% Al2O3, and also includes 0.1-2wt% of an auxiliary agent, which is one or more of the oxides of Pt, La, Zr and Cd; Preferably, the volume ratio of the carbon dioxide fed into the methanol synthesis unit to the hydrogen produced by the water electrolysis unit is 1:2.5-3.5, preferably 1:2.9-3.

1.

9. A green fuel production system using biomass as a raw material for implementing the method according to any one of claims 1 to 8, characterized by, The preparation system comprises: a water electrolysis unit for electrolyzing water to produce hydrogen and oxygen; a biomass gasification unit for contacting biomass with oxygen from the water electrolysis unit and a gasification agent to perform a gasification reaction to obtain a raw synthesis gas; a gas purification unit for purifying the raw synthesis gas to obtain a purified synthesis gas; a decarbonization unit for removing carbon dioxide from the purified synthesis gas to obtain carbon dioxide and decarbonized synthesis gas; a methanol synthesis unit for reacting carbon dioxide from the decarbonization unit and part of the hydrogen from the water electrolysis unit to produce methanol; a Fischer-Tropsch synthesis unit, the synthesis gas inlet of the Fischer-Tropsch synthesis unit is connected to the decarbonized synthesis gas outlet of the decarbonization unit through a decarbonized synthesis gas delivery pipeline, and the hydrogen delivery pipeline of the water electrolysis unit is connected to the decarbonized synthesis gas delivery pipeline to enable hydrogen to be fed into the decarbonized synthesis gas delivery pipeline; the Fischer-Tropsch synthesis unit is used to perform a Fischer-Tropsch synthesis reaction on the decarbonized synthesis gas to obtain a Fischer-Tropsch synthesis product and separate C5+ hydrocarbons from the Fischer-Tropsch synthesis product; a cracking and isomerization unit for contacting the C5+ hydrocarbons and part of the hydrogen gas from the water electrolysis hydrogen production unit for hydroconversion and fractionating the hydroconversion products to obtain C5-C7 gasoline component, C8-16 aviation kerosene component and tail oil fraction above 300℃.

10. The green fuel production system according to claim 9, wherein, a steam outlet of the Fischer-Tropsch synthesis unit is connected to the biomass gasification unit via a steam delivery line; and / or, a first off-gas output line of the Fischer-Tropsch synthesis unit and a second off-gas output line of the cracking and isomerization unit are respectively connected to the biomass gasification unit; and / or, a tail oil fraction outlet of the cracking and isomerization unit is connected to a hydroconversion feedstock inlet of the cracking and isomerization unit via a tail oil fraction recycle line; and / or, the production system further comprises a pre-treatment unit for pre-treating the biomass including drying and pelleting to provide the pre-treated biomass to the biomass gasification unit; and / or, the Fischer-Tropsch synthesis unit comprises a Fischer-Tropsch synthesis reactor, which is a fixed bed reactor; and / or, the water electrolysis hydrogen production unit is powered by green electricity.

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