Process for producing sustainable aviation fuel by capturing carbon dioxide of industrial boiler with industrial byproduct hydrogen

Abstract

The invention relates to the technical field of sustainable aviation fuel preparation processes, and discloses a process for producing sustainable aviation fuel by capturing carbon dioxide of an industrial boiler with an industrial byproduct hydrogen, which comprises the following steps: S1, raw material pretreatment; s2, converting hydrogen and carbon dioxide in the raw materials into Fischer-Tropsch synthesis gas by using a catalyst; s3, converting the Fischer-Tropsch synthesis gas obtained in S2 into liquid alkane; s4, the liquid alkane obtained in S3 is subjected to hydroisomerization to generate sustainable aviation fuel, industrial by-products of hydrogen and carbon dioxide can be converted into the sustainable aviation fuel through the steps of Fischer-Tropsch synthesis, hydroisomerization and the like, the fuel can serve as a substitute of petroleum fuel, dependence on traditional petroleum resources is reduced, and the sustainable aviation fuel is obtained. According to the invention, not only can sustainable aviation fuel be produced, but also light products (C5-C8 alkanes) and heavy products (C16-C24 alkanes) can be generated, and the light products and the heavy products can be respectively used for further Fischer-Tropsch synthesis reaction and can be sold as automotive second-generation biodiesel.

Description

Technical Field

[0001] The invention relates to the technical field of sustainable aviation fuel preparation technology, and specifically to a process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen. Background Art

[0002] Sustainable aviation fuel is an alternative fuel produced in a sustainable way using waste animal and vegetable fats, oils, used cooking oil, urban domestic waste and agricultural and forestry waste as raw materials.

[0003] Rising concentrations of carbon dioxide (CO2) in the global atmosphere have been shown to be closely linked to the earth's climate change. The combustion of fossil fuels in various engines increases the amount of CO2 in the atmosphere. Concerns about climate change have led to major societal changes around the world to renewable or low-carbon energy sources, which has also driven the decarbonization of the transportation sector. Today, the increasing use of electric vehicles, which are mainly powered by renewable energy, has contributed to the decarbonization of the transportation sector. However, the aviation industry remains one of the most carbon-intensive transportation sectors, accounting for more than 2% of global CO2 emissions. Most of the jet fuel consumed by the aviation industry is derived from fossil fuels such as petroleum, and the combustion of these fuels accounts for a significant proportion of the total global transportation CO2 emissions. Despite the development of sustainable aviation fuel (SAF), its cost is much higher than fossil fuel jet fuel. The electrification of jet aircraft will remain difficult to achieve in the foreseeable future. Therefore, the development of efficient and cost-effective SAF production processes will significantly reduce CO2 emissions from the aviation industry. Currently, ASTM D7566-21 specifies the production specifications for sustainable aviation fuels containing synthetic hydrocarbons. The catalytic hydrogenation of carbon monoxide (CO) produces, in addition to oxygenated hydrocarbons, gaseous, liquid and waxy substances ranging from methane to heavier hydrocarbons, commonly known as Fischer-Tropsch synthesis (FT synthesis). According to ASTM D7566, one of the permitted routes for the production of synthetic paraffinic kerosene (SPK) is via the FT synthesis process.

[0004] In the existing industrial production process, a large amount of industrial byproduct hydrogen is produced and is usually regarded as waste or byproduct. The utilization value of this hydrogen has not been fully utilized, resulting in a waste of resources. At the same time, industrial boiler tail gas contains a large amount of carbon dioxide, the emission of which exacerbates the greenhouse effect and has a serious impact on the environment. Therefore, a process for industrial byproduct hydrogen to capture carbon dioxide from industrial boilers to produce sustainable aviation fuel is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a process for capturing carbon dioxide from industrial boilers with industrial byproduct hydrogen to produce sustainable aviation fuel, so as to solve the problem that a large amount of industrial byproduct hydrogen is produced and is usually regarded as waste or byproduct, and the utilization value of these hydrogen is not fully utilized, resulting in a waste of resources. At the same time, the exhaust gas of industrial boilers contains a large amount of carbon dioxide, and the emission of these carbon dioxide exacerbates the greenhouse effect and has a serious impact on the environment.

[0006] To achieve the above object, the present invention provides the following technical solution: a process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen, comprising the following steps: S1, raw material pretreatment; S2, using a catalyst to convert hydrogen and carbon dioxide in the raw materials into Fischer-Tropsch synthesis gas; S3, converting the Fischer-Tropsch synthesis gas obtained in S2 into liquid alkanes; S4. Hydroisomerizing the liquid alkanes obtained in S3 to generate sustainable aviation fuel.

[0007] Preferably, in the above: in S1, the raw material includes industrial by-product hydrogen or industrial boiler tail gas.

[0008] Preferably, the industrial by-product hydrogen is pretreated by dry filtration using iron oxide to remove hydrogen sulfide and other impurities to obtain pretreated hydrogen; The industrial boiler tail gas pretreatment removes water vapor in the tail gas by molecular sieve adsorption, and uses a polymer membrane to selectively separate carbon dioxide to obtain pretreated carbon dioxide.

[0009] Preferably, in the above: in S2, the catalyst is an iron catalyst containing a promoter potassium; The hydrogen and carbon dioxide are mixed and catalyzed by a catalyst to convert them into a Fischer-Tropsch gas of carbon monoxide and water vapor. The water vapor in the Fischer-Tropsch gas is removed by a molecular sieve adsorption method to obtain a dry Fischer-Tropsch synthesis gas.

[0010] Preferably, the above-mentioned reaction temperature of hydrogen and carbon dioxide is 200-400°C, the pressure is 20-30 bar, and the reaction time is 1-2 hours.

[0011] Preferably, in the above: in S3, the Fischer-Tropsch synthesis gas is introduced into a fixed bed reactor, and the catalyst is a cobalt catalyst with potassium additive added; The reaction temperature is 200-350°C, and the reaction pressure is 20-40 bar.

[0012] Preferably, as mentioned above: after the internal reaction of the fixed bed reactor is completed, a synthesis gas is obtained, and the ratio of CO to H2 in the synthesis gas is 1:2-2:1.

[0013] Preferably, the above: the synthesis gas is cooled to obtain liquid alkane; The liquid alkanes are separated into light products (C5 to C8 alkanes), medium products (C9 to C15 alkanes) and heavy products (C16 to C24 alkanes) through staged condensation.

[0014] Preferably, in the above-mentioned S4, the hydroisomerization is conducted into a fixed bed reactor to produce a medium-sized product (C9 to C15 alkane), and the isomerization reaction is conducted using a platinum catalyst supported by aluminum chloride (Al2Cl3).

[0015] Preferably, the reaction temperature is 200-250° C., the reaction pressure is 20-30 bar, the reaction time is 1-2 hours, the ratio of hydrogen to alkane is 3:1-10:1, and sustainable aviation fuel is obtained after the reaction.

[0016] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: 1. The process of the present invention preferentially utilizes low-cost, high-yield industrial by-product hydrogen as a hydrogen source. This hydrogen is usually regarded as waste or by-product. It can be reused through this process, thereby improving the overall utilization efficiency of resources. The carbon dioxide in industrial boiler exhaust is usually regarded as the source of greenhouse gas emissions. This process achieves resource utilization of waste and reduces greenhouse gas emissions by capturing and converting this carbon dioxide.

[0017] 2. Through Fischer-Tropsch synthesis and hydroisomerization steps, the process can convert industrial by-product hydrogen and carbon dioxide into sustainable aviation fuel. The fuel can be used as a substitute for petroleum fuel, helping to reduce dependence on traditional petroleum resources. It can not only produce sustainable aviation fuel, but also generate light products (C5 to C8 alkanes) and heavy products (C16 to C24 alkanes), which can be used for further Fischer-Tropsch synthesis reactions and sold as second-generation biodiesel for vehicles, achieving diversified utilization of products. The entire process not only avoids greenhouse gas emissions, but also achieves dual emission reduction capabilities through the synthesis of alternatives to petroleum fuels, which is of positive significance to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0021] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by this application. Example

[0022] See also Figure 1 The present invention provides a technical solution for a process of using industrial byproduct hydrogen to capture carbon dioxide from industrial boilers to produce sustainable aviation fuel, comprising the following steps: S1, raw material pretreatment; The raw materials include industrial by-product hydrogen or industrial boiler exhaust gas.

[0023] Industrial by-product hydrogen is pretreated by dry filtration using iron oxide to remove hydrogen sulfide and other impurities to obtain pretreated hydrogen; the composition and purity of by-product hydrogen will vary depending on the source and specific process, and the main components are as follows: Hydrogen is usually 70-95% hydrogen, but the concentration may vary depending on the source.

[0024] Carbon monoxide levels may be around 1-10%, carbon dioxide levels are usually less than 5%, and small amounts of nitrogen, usually between 1-3%.

[0025] Trace amounts of hydrogen sulfide, hydrocarbons (such as ethylene, ethane) and other trace impurities.

[0026] Industrial boiler tail gas pretreatment removes water vapor from tail gas through molecular sieve adsorption, and uses polymer membranes for selective separation of carbon dioxide to obtain pretreated carbon dioxide. The polymer membrane is polyimide or polyetheramide. According to the dissolution and diffusion mechanism, gas molecules first dissolve on the surface of the membrane, then diffuse through the inside of the membrane, and finally desorb on the other side of the membrane. Different gases have different solubility and diffusion rates in the membrane, resulting in their selective separation. For polymer membranes, the solubility of carbon dioxide is usually higher than that of oxygen and nitrogen, thus achieving separation.

[0027] Industrial boiler tail gas is significantly affected by factors such as fuel type, such as coal, natural gas, heavy oil, etc., combustion equipment, etc. The main components usually include: carbon dioxide content is about 15-25%, water vapor content is usually 10-15%, oxygen in the air that is not completely consumed is generally about 1-5%, and nitrogen in the air that is not completely consumed is usually 65-85%.

[0028] S2, using a catalyst to convert hydrogen and carbon dioxide in the raw materials into Fischer-Tropsch synthesis gas; The catalyst is an iron catalyst containing a potassium promoter; the iron catalyst containing potassium promoter is suitable for operation at a relatively high temperature, usually at 300-350°C, has a high efficiency in generating synthesis gas, has strong toxicity resistance, and can be used in gases with impurities.

[0029] Hydrogen and carbon dioxide are mixed and converted into a Fischer-Tropsch gas of carbon monoxide and water vapor using a catalyst. Water vapor in the Fischer-Tropsch gas is removed by molecular sieve adsorption to obtain dry Fischer-Tropsch synthesis gas. The ratio of the iron catalyst of the promoter potassium to hydrogen and carbon dioxide is 1:1.

[0030] The reaction temperature of hydrogen and carbon dioxide is 300°C, the pressure is 25 bar, and the reaction time is 1.5 hours.

[0031] S3, converting the Fischer-Tropsch synthesis gas obtained in S2 into liquid alkanes; The Fischer-Tropsch synthesis gas is introduced into a fixed bed reactor, and the catalyst is a cobalt catalyst with potassium additive added; the cobalt catalyst with potassium additive added has a higher selectivity for synthesis gas and can more effectively generate liquid hydrocarbons. The reaction temperature is 300°C and the reaction pressure is 30 bar. After the internal reaction of the fixed bed reactor is completed, synthesis gas is obtained, and the ratio of CO to H2 in the synthesis gas is 1:2-2:1.

[0032] Liquid alkanes are obtained after the synthesis gas is cooled; Liquid alkanes are separated into light products (C5 to C8 alkanes), medium products (C9 to C15 alkanes) and heavy products (C16 to C24 alkanes) by staged condensation.

[0033] Medium products (C9 to C15 alkanes) account for 40% to 100%. Medium products (C9 to C15 alkanes) are fed into a fixed bed reactor for the production of sustainable aviation fuel, light products (C5 to C8 alkanes) continue to undergo Fischer-Tropsch synthesis reaction, and heavy products (C16 to C24 alkanes) can be sold as second-generation biodiesel for vehicles.

[0034] S4. Hydroisomerizing the liquid alkanes obtained in S3 to generate sustainable aviation fuel.

[0035] The hydroisomerization is introduced into a fixed bed reactor to produce medium products (C9 to C15 alkanes), and the isomerization reaction is carried out using a platinum catalyst supported by aluminum chloride (Al2Cl3).

[0036] The reaction temperature is 225°C, the reaction pressure is 25 bar, the reaction time is 1.5 hours, and the ratio of hydrogen to alkane is 3:1-10:1. Adequate hydrogen supply is essential to maintaining catalyst activity and ensuring rapid isomerization. Alkanes are converted into branched alkanes, thereby improving the low-temperature fluidity of the fuel. Through hydrogenation isomerization, the freezing point of the product drops to between -40°C and -60°C, and sustainable aviation fuel is obtained after the reaction.

[0037] The present invention preferentially utilizes low-cost, high-yield industrial by-product hydrogen as a hydrogen source. Compared with methanol hydrogen production, coal hydrogen production and water electrolysis hydrogen production, the investment is smaller. The reuse of industrial by-product hydrogen belongs to the comprehensive utilization of waste resources. Industrial by-product hydrogen is reacted with carbon dioxide to generate a gas stream containing carbon monoxide. The generated gas stream is synthesized through a Fischer-Tropsch synthesis reaction to generate a liquid product composed of alkanes with a carbon number of 5 to 24, of which 40% to 100% are C9 to C15 alkane fractions. The liquid product is separated into three streams: light products (C5 to C8 alkanes), medium products (C9 to C15 alkanes) and The heavy products (C16 to C24 alkanes) and the product stream of the medium fraction are fed into a fixed bed reactor. In the process, the alkanes are converted into branched alkanes, thereby improving the low-temperature fluidity of the fuel. Through hydrogenation isomerization, the freezing point of the product is reduced to between -40°C and -60°C. The light fraction products continue to be synthesized by Fischer-Tropsch synthesis reaction, and the heavy fraction products can be sold as second-generation biodiesel for vehicles. The raw materials used in the present invention are industrial by-product hydrogen and industrial boiler tail gas carbon dioxide, which not only avoids greenhouse gas emissions, but also synthesizes a substitute for petroleum fuels, and has dual emission reduction capabilities.

[0038] In summary, the process of the present invention preferentially utilizes low-cost, high-yield industrial by-product hydrogen as a hydrogen source. These hydrogens are usually regarded as waste or by-products. Through this process, they can be reused, thereby improving the overall utilization efficiency of resources. The carbon dioxide in industrial boiler exhaust gas is usually regarded as the source of greenhouse gas emissions. This process achieves resource utilization of waste and reduces greenhouse gas emissions by capturing and converting these carbon dioxide.

[0039] Through steps such as Fischer-Tropsch synthesis and hydroisomerization, the process can convert industrial by-product hydrogen and carbon dioxide into sustainable aviation fuel. The fuel can be used as a substitute for petroleum fuel, helping to reduce dependence on traditional petroleum resources. It can not only produce sustainable aviation fuel, but also generate light products (C5 to C8 alkanes) and heavy products (C16 to C24 alkanes), which can be used for further Fischer-Tropsch synthesis reactions and sold as second-generation biodiesel for vehicles, respectively, thus achieving diversified utilization of products. The entire process not only avoids greenhouse gas emissions, but also achieves dual emission reduction capabilities by synthesizing substitutes for petroleum fuels, which is of positive significance to environmental protection.

[0040] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

Claims

1. A process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen, characterized in that: The following steps are involved: S1, raw material pretreatment; S2, using a catalyst to convert hydrogen and carbon dioxide in the raw materials into Fischer-Tropsch synthesis gas; S3, converting the Fischer-Tropsch synthesis gas obtained in S2 into liquid alkanes; S4. Hydroisomerizing the liquid alkanes obtained in S3 to generate sustainable aviation fuel.

2. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 1, characterized in that: In S1, the raw material includes industrial by-product hydrogen or industrial boiler tail gas.

3. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 2, characterized in that: The industrial by-product hydrogen is pretreated by dry filtration using iron oxide to remove hydrogen sulfide and other impurities to obtain pretreated hydrogen; The industrial boiler tail gas pretreatment removes water vapor in the tail gas by molecular sieve adsorption, and uses a polymer membrane to selectively separate carbon dioxide to obtain pretreated carbon dioxide.

4. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 3, characterized in that: In S2, the catalyst is an iron catalyst containing a promoter of potassium; The hydrogen and carbon dioxide are mixed and catalyzed by a catalyst to convert them into a Fischer-Tropsch gas of carbon monoxide and water vapor. The water vapor in the Fischer-Tropsch gas is removed by a molecular sieve adsorption method to obtain a dry Fischer-Tropsch synthesis gas.

5. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 4, characterized in that: The reaction temperature of hydrogen and carbon dioxide is 200-400° C., the pressure is 20-30 bar, and the reaction time is 1-2 hours.

6. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 4, characterized in that: In S3, the Fischer-Tropsch synthesis gas is introduced into a fixed bed reactor, and the catalyst is a cobalt catalyst with potassium as an additive; The reaction temperature is 200-350°C, and the reaction pressure is 20-40 bar.

7. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 6, characterized in that: After the internal reaction of the fixed bed reactor is completed, synthesis gas is obtained, and the ratio of CO to H2 in the synthesis gas is 1:2-2:

1.

8. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 7, characterized in that: The synthesis gas is cooled to obtain liquid alkane; The liquid alkanes are separated into light products (C5 to C8 alkanes), medium products (C9 to C15 alkanes) and heavy products (C16 to C24 alkanes) through staged condensation.

9. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 8, characterized in that: In S4, the hydroisomerization is introduced into a fixed bed reactor into a medium product (C9 to C15 alkane), and an isomerization reaction is carried out using a platinum catalyst supported by aluminum chloride (Al2Cl3).

10. The process for producing sustainable aviation fuel by capturing carbon dioxide from industrial boilers using industrial byproduct hydrogen according to claim 9, characterized in that: The reaction temperature is 200-250° C., the reaction pressure is 20-30 bar, the reaction time is 1-2 hours, the ratio of hydrogen to alkane is 3:1-10:1, and sustainable aviation fuel is obtained after the reaction is completed.

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