Methane cracking hydrogen production coupled with hefa to produce saf process and system

Abstract

The application provides a methane cracking hydrogen production coupling HEFA SAF production process and system, which comprises the following units: a methane cracking hydrogen production unit for catalytically cracking methane to obtain hydrogen and carbon material; an HEFA SAF production unit for hydrogen produced in the methane cracking hydrogen production unit and renewable oil and fat to undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst to be converted into renewable aviation fuel; a carbon reduction unit for converting carbon dioxide tail gas generated in the hydrogenation reaction of the HEFA SAF production unit and carbon generated in the methane cracking hydrogen production unit into carbon monoxide; and a mixing unit for receiving the carbon monoxide generated in the carbon reduction unit and another part of the hydrogen generated in the methane cracking hydrogen production unit, and obtaining synthesis gas after mixing. The methane cracking hydrogen production and the HEFA SAF production are coupled to form a hydrogen production-SAF production-carbon reduction-synthesis gas closed loop, so that the overall efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of aviation fuel and preparation technology, and in particular to a process and system for producing SAF by coupling methane cracking to hydrogen production with HEFA. Background Technology

[0002] HEFA-SAF is an abbreviation for Hydroprocessed Esters and Fatty Acids Sustainable Aviation Fuel. The HEFA-SAF process refers to the process of converting renewable oil and fat feedstocks into synthetic paraffin-based jet fuel with properties similar to traditional aviation kerosene through a series of chemical treatments such as hydrodeoxygenation, isomerization / cracking. It can be mixed with fossil aviation kerosene in a certain proportion without the need to modify existing aircraft engines and fuel supply infrastructure.

[0003] Currently, the HEFA-SAF production process suffers from a vicious cycle of high energy consumption and low efficiency. First, raw material pretreatment requires a filtration stage, consuming 15%-20% of the raw material cost. Second, the hydrogenation reaction relies on high temperature and pressure conditions (typically 300℃-400℃, 5 MPa-10 MPa), and hydrogen consumption is enormous. If grey hydrogen (hydrogen produced from fossil fuels) is used, the carbon emissions over its entire lifecycle will increase by 40%, offsetting its environmental advantages. Conventional green hydrogen comes from water electrolysis, and renewable electricity-powered water electrolysis has become the mainstream hydrogen source choice supported by policies and favored by the industry due to its environmental attributes (zero carbon emissions) and readily available raw materials (requiring only water and electricity). However, in reality, the cost of green hydrogen is currently as high as 35-40 yuan / kg, far exceeding the cost of traditional fossil fuel-based hydrogen production (such as coal-to-hydrogen and natural gas-to-hydrogen). This causes the price of SAF to climb to 3-5 times that of traditional jet fuel. Furthermore, the current HEFA-SAF production process also suffers from insufficient carbon utilization, resulting in CO2 emissions and environmental impact. Summary of the Invention

[0004] To address the problems existing in the background technology, the present invention provides a process and system for methane cracking to produce hydrogen coupled with HEFA to produce SAF.

[0005] The specific details of the invention are as follows: In a first aspect, the present invention provides a methane cracking hydrogen production coupled HEFA to SAF production system, comprising: a methane cracking hydrogen production unit, an HEFA to SAF production unit, a carbon reduction unit and a mixing unit; Among them, the methane cracking hydrogen production unit is used to catalytically crack methane to obtain hydrogen and carbon materials; The HEFA SAF production unit is connected to the methane cracking hydrogen production unit and is used to receive part of the hydrogen generated in the methane cracking hydrogen production unit. Using renewable oil as raw material, the renewable oil and the hydrogen undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst to convert them into renewable aviation fuel. The carbon reduction unit is connected to the HEFA-to-SAF unit and the methane cracking-to-hydrogen unit respectively, and is used to receive the carbon material generated in the methane cracking-to-hydrogen unit and the carbon dioxide tail gas generated when the HEFA-to-SAF unit undergoes hydrogenation reaction, so that the carbon dioxide tail gas reacts with the carbon material to undergo an oxidation-reduction reaction and be converted into carbon monoxide. The mixing unit is connected to both the carbon reduction unit and the methane cracking hydrogen production unit, and is used to receive carbon monoxide generated in the carbon reduction unit and another portion of hydrogen generated in the methane cracking hydrogen production unit, and mix them to obtain syngas.

[0006] Optionally, the HEFA-to-SAF unit includes: a hydrodeoxygenation reactor and a hydrocracking reactor; The hydrodeoxygenation reactor is connected to the methane cracking hydrogen production unit and the carbon reduction unit respectively. The hydrodeoxygenation reactor is used to receive part of the hydrogen generated in the methane cracking hydrogen production unit and the renewable oil, so that the renewable oil and the hydrogen undergo a hydrodeoxygenation reaction to be converted into hydrocarbons and generate carbon dioxide tail gas which is then transported to the carbon reduction unit to participate in the redox reaction. The hydrocracking reactor is used to receive hydrocarbons generated in the hydrodeoxygenation reactor and a portion of the hydrogen generated in the methane cracking hydrogen production unit, so that the hydrocarbons and the hydrogen undergo a hydrocracking / isomerization reaction to be converted into the renewable aviation fuel.

[0007] Optionally, the system further includes: a first heat exchange unit, which is connected to the methane cracking hydrogen production unit, the carbon reduction unit, and the mixing unit respectively. The first heat exchange unit is used to receive carbon monoxide generated in the carbon reduction unit and methane feed gas, so that the methane feed gas and the carbon monoxide exchange heat. After the temperature of the methane feed gas reaches the temperature required for the cracking reaction, it is then transported to the methane cracking hydrogen production unit to participate in the reaction. The carbon monoxide cooled by heat exchange is transported to the mixing unit to participate in the preparation of syngas.

[0008] Optionally, the system further includes a second heat exchange unit, which is connected to the methane cracking hydrogen production unit, the HEFA-to-SAF unit, and the mixing unit. The second heat exchange unit receives hydrogen generated in the methane cracking hydrogen production unit and exchanges heat with the renewable oil to bring the temperature of the renewable oil and hydrogen to a preset temperature. Then, the renewable oil and a portion of the hydrogen are transported to the HEFA-to-SAF unit to participate in hydrodeoxygenation and hydrocracking / isomerization reactions, and the remaining hydrogen is transported to the mixing unit for syngas production.

[0009] In a second aspect, the present invention provides a process for producing SAF by coupling methane cracking to hydrogen with HEFA, the process being applicable to the system described in the first aspect above, comprising: Methane is fed into a methane cracking hydrogen production unit, where it undergoes a catalytic cracking reaction to produce hydrogen and carbon materials. The renewable oil and a portion of the hydrogen are introduced into the HEFA-to-SAF unit. Under the action of a catalyst, the renewable oil undergoes hydrodeoxygenation and hydrocracking / isomerization reactions to be converted into renewable aviation fuel. The carbon dioxide tail gas generated during the hydrodeoxygenation reaction of the carbon material and the renewable oil is passed into the carbon reduction unit for mixing, so that the carbon material and the carbon dioxide tail gas undergo an oxidation-reduction reaction and are converted into carbon monoxide. The carbon monoxide and another portion of the hydrogen generated in the methane cracking hydrogen production unit are then mixed in a mixing unit to obtain syngas.

[0010] Optionally, before the methane participating in the catalytic cracking reaction is introduced into the methane cracking hydrogen production unit, the process further includes: The methane and carbon monoxide generated in the carbon reduction unit are passed into the first heat exchange unit for heat exchange, so that the temperature of the methane feed gas reaches the temperature required for the cracking reaction. Then, it is sent to the methane cracking hydrogen production unit to participate in the reaction. The carbon monoxide that has been cooled by heat exchange is sent to the mixing unit to participate in the preparation of the synthesis gas.

[0011] Optionally, the catalyst used in the catalytic cracking reaction is selected from biochar materials with a thickness of 200 μm to 600 μm.

[0012] Optionally, before the hydrogen generated by the catalytic cracking reaction is introduced into the HEFA to SAF production unit to participate in the reaction, the process further includes: The hydrogen generated in the methane cracking hydrogen production unit is introduced into the second heat exchange unit to exchange heat with the renewable oil. After the renewable oil is heated to the temperature required for hydrodeoxygenation and hydrocracking / isomerization reaction, it is then transported together with some hydrogen to the HEFA to SAF production unit to participate in the reaction.

[0013] Optionally, the catalyst used for the hydrodeoxygenation reaction of the renewable oil is selected from nickel-molybdenum system catalysts, and the catalyst used for the hydrocracking / isomerization reaction is selected from molecular sieve catalysts.

[0014] Optionally, the heat source for the oxidation-reduction reaction between the carbon material and the carbon dioxide exhaust gas to convert it into carbon monoxide includes: high-temperature exhaust gas containing CO2 generated from coal combustion or biomass waste co-firing.

[0015] Compared with the prior art, the present invention has the following advantages: This invention provides a methane cracking hydrogen production coupled with HEFA to SAF production system, comprising: a methane cracking hydrogen production unit for catalytic cracking of methane to obtain hydrogen and carbon materials; an HEFA to SAF production unit for receiving a portion of the hydrogen generated in the methane cracking hydrogen production unit and renewable oil, so that the renewable oil and the hydrogen undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst to convert them into renewable aviation fuel; a carbon reduction unit for receiving the carbon materials generated in the methane cracking hydrogen production unit and carbon dioxide tail gas generated during the hydrogenation reaction in the HEFA to SAF production unit, so that the carbon dioxide tail gas and the carbon materials undergo a redox reaction to convert them into carbon monoxide; and a mixing unit for receiving the carbon monoxide generated in the carbon reduction unit and another portion of the hydrogen generated in the methane cracking hydrogen production unit, mixing them to obtain syngas with different H / C requirements; This invention couples the methane cracking hydrogen production process with the HEFA (Heated Carbon Fiber Atomizer) process to produce SAF (Synthetic Gas), and forms a closed loop of "hydrogen production - SAF production - carbon reduction - syngas" by interconnecting materials (H2, CO2) and energy (waste heat), thereby improving overall efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of the methane cracking hydrogen production coupled HEFA to SAF production system provided in an embodiment of the present invention is shown; Figure 2 This invention provides a schematic diagram of another methane cracking hydrogen production coupled with HEFA to SAF system structure according to an embodiment of the present invention; Figure 3 This invention provides a flow chart of another methane cracking hydrogen production coupled with HEFA to SAF process according to an embodiment of the invention. Figure 4 The diagram illustrates the material and energy flow in the methane cracking hydrogen production coupled with HEFA to SAF process provided in this embodiment of the invention.

[0018] Explanation of reference numerals in the attached figures: 1-Methane cracking hydrogen production unit; 2-HEFA to SAF production unit; 2-1-Hydrodeoxygenation reactor; 2-2-Hydrocracking reactor; 3-Carbon reduction unit; 4-Mixing unit; 5-First heat exchange unit; 6-Second heat exchange unit. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0020] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0021] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0022] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] In a first aspect, the present invention provides a methane cracking hydrogen production coupled with HEFA to SAF production system, see [link to relevant documentation]. Figure 1The system schematic shown is a methane cracking hydrogen production coupled HEFA to SAF production system, which includes: a methane cracking hydrogen production unit 1, an HEFA to SAF production unit 2, a carbon reduction unit 3, and a mixing unit 4. The HEFA to SAF production unit 2 is connected to the methane cracking hydrogen production unit 1 and the carbon reduction unit 3 through pipelines. A material transfer pipeline is provided between the carbon reduction unit 3 and the methane cracking hydrogen production unit 1. The mixing unit 4 is connected to the carbon reduction unit 3 and the methane cracking hydrogen production unit 1 through pipelines.

[0024] In specific implementation, this invention uses methane cracking to produce hydrogen instead of high-cost green hydrogen. The methane cracking hydrogen production unit 1 is used for catalytic cracking of methane to obtain hydrogen and carbon materials. Specifically, the methane cracking hydrogen production unit 1 can be a fluidized bed reactor. The hydrogen produced from the methane cracking is used to supply the hydrogenation and hydrocracking / isomerization sections of the HEFA-to-SAF system, reducing hydrogen source costs. The HEFA-to-SAF unit 2 receives a portion of the hydrogen generated in the methane cracking hydrogen production unit, as well as renewable oils, so that the renewable oils and hydrogen undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst, converting them into renewable aviation fuel. The heat energy required for the hydrodeoxygenation and hydrocracking / isomerization reactions is provided by the heat carried by the hydrogen entering the HEFA-to-SAF unit 2, eliminating the need for external energy input. Carbon reduction unit 3 receives the carbon material generated from methane cracking in the methane cracking hydrogen production unit, as well as the carbon dioxide tail gas generated during the hydrogenation reaction in the HEFA-to-SAF unit. This allows the carbon dioxide tail gas to undergo a redox reaction with the carbon material, converting it into carbon monoxide. This enables the carbon dioxide waste gas generated during the operation of HEFA-to-SAF unit 2 to react with the solid carbon material (C), a byproduct of methane cracking, in carbon reduction unit 3 (1000-1500℃), converting the carbon dioxide waste gas into more economically valuable CO, thus avoiding direct CO2 emissions and environmental impact. Mixing unit 4 receives the carbon monoxide generated in carbon reduction unit 3 and another portion of the hydrogen generated in the methane cracking hydrogen production unit. The mixture yields syngas. By adjusting the ratio of H2 to CO introduced into mixing unit 4, syngas with different hydrogen-to-carbon ratios can be generated for co-production of methanol, FT-SAF, and other products.

[0025] In this embodiment, a portion of the hydrogen produced by methane cracking provides a hydrogen source for the production of jet fuel. Simultaneously, the high-temperature hydrogen also provides heat energy for the hydrodeoxygenation and hydrocracking / isomerization reactions of renewable oils in HEFA-to-SAF unit 2. The CO2 tail gas separated from HEFA-to-SAF unit 2 undergoes a high-temperature carbon reduction reaction with the carbon materials produced as byproducts in methane cracking-to-hydrogen unit 1 to produce CO. The resulting carbon monoxide is mixed with the remaining H2 in methane cracking-to-hydrogen unit 1. By adjusting the hydrogen-to-carbon ratio, syngas with different hydrogen-to-carbon ratios is obtained for downstream markets, achieving the reuse of carbon solid waste. By coupling methane cracking with HEFA-to-SAF production, the utilization rate of materials is improved, forming a closed loop of "hydrogen production-SAF production-carbon reduction-syngas," thereby enhancing overall efficiency.

[0026] In specific implementation, the HEFA-to-SAF unit 2 includes: a hydrodeoxygenation reactor 2-1 and a hydrocracking reactor 2-2; The hydrodeoxygenation reactor 2-1 is connected to the methane cracking hydrogen production unit 1 and the carbon reduction unit 3 respectively. The hydrodeoxygenation reactor 2-1 is used to receive part of the hydrogen generated in the methane cracking hydrogen production unit 1 and the renewable oil, so that the renewable oil and the hydrogen undergo a hydrodeoxygenation reaction to be converted into hydrocarbons. The carbon dioxide tail gas generated by gas-liquid separation is transported to the carbon reduction unit 3 to participate in the redox reaction. The hydrodeoxygenation reactor 2-1 is preferably a fixed bed reactor. The hydrocracking reactor 2-2 is used to receive the target hydrocarbons generated in the hydrodeoxygenation reactor 2-1 and a portion of the hydrogen generated in the methane cracking hydrogen production unit 1, so that the hydrocarbons and the hydrogen undergo a hydrocracking / isomerization reaction to be converted into the renewable aviation fuel.

[0027] It should be noted that, in order to ensure the long-term stable operation of the HEFA section in HEFA-to-SAF unit 2, and to make efficient use of hydrogen without wasting hydrogen produced from methane cracking, the renewable oils need to be pretreated before being introduced into HEFA-to-SAF unit 2. The pretreatment unit components include filters, dehydration towers, degumming towers, and deacidification towers, etc., to remove impurities, moisture, and gums from the renewable oils, protect the catalyst, and prevent bed blockage, poisoning, and pressure drop spikes. Furthermore, HEFA-based SAF production unit 2 also includes components for separating the reaction products after the hydrodeoxygenation (HDO) reaction of renewable oils, such as a high-pressure gas-liquid separator, flash tank, and propane removal tower, to separate propane, H2O, CO2, circulating hydrogen, and liquid hydrocarbons generated by HDO, so as to accurately deliver CO2 to carbon reduction unit 3, achieve carbon closed-loop, and eliminate emissions and waste; and HEFA-based SAF production unit 2 also includes components for separating the products generated in hydrocracking reactor 2-2, including: a fractionation tower (distillation tower), top condenser, and bottom reboiler, to cut out SAF jet fuel fractions, separate light components and diesel fractions, and produce qualified aviation fuel.

[0028] Furthermore, in this embodiment, the carbon monoxide generated in the carbon reduction unit 3 can reach a temperature of 1000–1500 ℃. After the high-temperature carbon monoxide exchanges heat with the raw material gas methane, the temperature of the methane raw material gas can be raised to the temperature required for the cracking reaction, providing the heat required for the reaction of the methane cracking unit 1, so as to realize the graded recovery and utilization of carbon monoxide heat without the need for additional heat source consumption.

[0029] For details, please refer to [link / reference]. Figure 2 The system diagram shown further includes a first heat exchange unit 5, which is connected to the methane cracking hydrogen production unit 1, the carbon reduction unit 3, and the mixing unit 4. The first heat exchange unit 5 receives carbon monoxide generated in the carbon reduction unit 3 and methane feed gas, so that the methane feed gas and the carbon monoxide exchange heat. After the temperature of the methane feed gas reaches the temperature required for the cracking reaction, it is then transported to the methane cracking hydrogen production unit 1 to participate in the reaction. The carbon monoxide, after being cooled by heat exchange, is transported to the mixing unit 4 to participate in the preparation of syngas.

[0030] Furthermore, in this embodiment, the temperature of the hydrogen generated in the methane cracking hydrogen production unit 1 can reach 600 ℃-1200 ℃, while the temperature required for the hydrodeoxygenation and hydrocracking / isomerization reaction of the renewable oil is below 450 ℃. Therefore, this embodiment, by setting up a second heat exchange unit 6, allows the hydrogen generated in the methane cracking hydrogen production unit 1 to exchange heat with the renewable oil. The heated renewable oil and a portion of the hydrogen are then fed into the HEFA to SAF production unit 2 to participate in the hydrodeoxygenation and hydrocracking / isomerization reaction of the renewable oil, further achieving cascaded heat recovery and utilization. The HEFA to SAF production unit 2 also does not require the addition of an additional heat source to successfully complete the conversion of the renewable oil.

[0031] For details, please refer to [link / reference]. Figure 2 The system schematic diagram shows that the second heat exchange unit 6 is connected to the methane cracking hydrogen production unit 1, the HEFA to SAF production unit 2, and the mixing unit 4. The second heat exchange unit 6 is used to receive hydrogen generated in the methane cracking hydrogen production unit 1 and exchange heat with the renewable oil. After the renewable oil is heated to the temperature required for hydrodeoxygenation, it is transported to the HEFA to SAF production unit 2 along with some hydrogen to participate in hydrodeoxygenation and hydrocracking / isomerization reactions. The other part of the hydrogen is introduced into the mixing unit 4 for syngas production.

[0032] Secondly, the present invention provides a process for producing SAF from methane through cracking and coupling with HEFA (hydrogenation-enhanced chemical assembly), the process being applicable to the system described in the first aspect above. Figure 3 A process flow diagram of methane cracking to hydrogen coupled with HEFA to SAF process provided in an embodiment of the present invention is shown, as follows: Figure 3 As shown, it includes: S1. Methane is introduced into the methane cracking hydrogen production unit, where it undergoes a catalytic cracking reaction to produce hydrogen and carbon materials. S2. The renewable oil and a portion of the hydrogen are introduced into the HEFA to SAF production unit. Under the action of a catalyst, the renewable oil undergoes hydrodeoxygenation and hydrocracking / isomerization reactions to be converted into renewable aviation fuel. S3. The carbon dioxide tail gas generated when the carbon material and the renewable oil undergo a hydrodeoxygenation reaction is introduced into the carbon reduction unit for mixing, so that the carbon material and the carbon dioxide tail gas undergo an oxidation-reduction reaction and are converted into carbon monoxide. S4. The carbon monoxide and another portion of the hydrogen generated in the methane cracking hydrogen production unit are passed into a mixing unit and mixed to obtain syngas.

[0033] In specific implementation, this invention uses methane cracking to produce hydrogen instead of high-cost green hydrogen. The methane cracking hydrogen production unit is used to catalytically crack methane to obtain hydrogen and carbon materials. Specifically, the methane cracking hydrogen production unit can be a fluidized bed reactor. The hydrogen produced by methane cracking is used to supply the hydrogenation and hydrocracking / isomerization sections of the HEFA-to-SAF system, reducing the cost of hydrogen sources. The HEFA-to-SAF unit receives a portion of the hydrogen generated in the methane cracking hydrogen production unit, as well as renewable oils, so that the renewable oils and hydrogen undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst, converting them into renewable aviation fuel. The heat energy required for the hydrodeoxygenation and hydrocracking / isomerization reactions is provided by the heat carried by the hydrogen entering the HEFA-to-SAF unit, without the need for external energy input. The carbon reduction unit receives the carbon material generated from the methane cracking to hydrogen production unit, as well as the carbon dioxide tail gas generated during the hydrogenation reaction in the HEFA to SAF unit. This allows the carbon dioxide tail gas to undergo a redox reaction with the carbon material, converting it into carbon monoxide. This enables the carbon dioxide waste gas generated during the operation of the HEFA to SAF unit to react with the solid carbon material (C), a byproduct of methane cracking, in the carbon reduction unit (1000-1500℃), converting the carbon dioxide waste gas into more economically valuable CO, thus avoiding the direct environmental impact of CO2 emissions. The mixing unit receives the carbon monoxide generated in the carbon reduction unit and another portion of the hydrogen generated in the methane cracking to hydrogen production unit. After mixing, syngas is obtained. By adjusting the ratio of H2 to CO introduced into the mixing unit, syngas with different hydrogen-to-carbon ratios are generated for co-production of methanol, FT-SAF, and other products.

[0034] The hydrogen obtained from the methane cracking hydrogen production unit can be used to provide a hydrogen source for the hydrodeoxygenation and hydrocracking stages of the HEFA to SAF route. The carbon materials produced by the methane cracking byproduct can be reacted with the waste gas - CO2 produced by the HEFA route to produce CO. The CO is further mixed with the remaining hydrogen obtained from the methane cracking hydrogen production unit to produce syngas. By adjusting the ratio of H2 and CO, syngas with different hydrogen-to-carbon ratios can be obtained, which can be used to co-produce other products (including but not limited to methanol, FT-SAF route, etc.).

[0035] It should be noted that the methane cracking hydrogen production unit operates at atmospheric pressure and 600℃-1200℃, preferably 800℃. The required heat of reaction can be recovered from the waste heat of CO produced by the high-temperature carbon fixation reaction (1000-1500℃). The catalyst used for methane cracking into hydrogen is preferably 200 μm-600 μm biochar. After the reaction, the solid product does not need to be separated and can be directly fed into carbon reduction unit 3 to participate in the high-temperature carbon fixation reduction reaction. Preferably, when the reactant methane is selected from biomethane, the entire process can achieve green attributes and meet EU carbon emission requirements for all stages.

[0036] It should be noted that renewable oils include, but are not limited to, animal / plant-based renewable oils and waste recycling oils, such as waste cooking oil, tallow, mutton tallow, and lard.

[0037] In practice, the HEFA-to-SAF unit involves at least the following two stages in which renewable oils undergo hydrodeoxygenation and hydrocracking / isomerization reactions to be converted into renewable aviation fuel: Hydrodeoxygenation section: The hydrodeoxygenation section is carried out in a hydrodeoxygenation reactor, specifically a fixed-bed reactor. The hydrodeoxygenation reactor receives part of the hydrogen generated from the methane cracking hydrogen production unit, as well as renewable oil, so that the renewable oil and the hydrogen undergo a hydrodeoxygenation reaction to convert into hydrocarbons. The catalyst used for the hydrodeoxygenation of renewable oil is preferably a nickel-molybdenum system catalyst, such as a NiMo / Al2O3 catalyst (NiMo content 10-20 wt%), and the reaction can be carried out at 1-20 MPa. The carbon dioxide tail gas generated after the deoxygenation section is sent to the carbon reduction unit to react with the carbon materials of the methane cracking byproduct to obtain CO.

[0038] Hydrocracking / Isomerization Section: The hydrocracking / isomerization section is carried out in a hydrocracking reactor, specifically a fixed-bed reactor. The hydrocracking reactor receives the target hydrocarbons generated in the hydrodeoxygenation reactor and a portion of the hydrogen generated in the methane cracking hydrogen production unit, so that the hydrocarbons and the hydrogen undergo a hydrocracking / isomerization reaction to convert them into the renewable aviation fuel. The catalyst is a molecular sieve catalyst, such as a Pt / SAPO-11 bifunctional catalyst (Pt content 0.01-5 wt%, SAPO-11 silicon-aluminum ratio 0.15-0.3, specific surface area 50-400 m²). 2 / g), hydrogen pressure: 1-15MPa.

[0039] It should be noted that the products generated in the hydrodeoxygenation reactor must undergo necessary separation processes before the separated target hydrocarbons are introduced into the hydrocracking reactor for further hydrocracking / isomerization reactions to obtain renewable aviation fuel. The separated carbon dioxide is precisely sent to the carbon reduction unit to achieve carbon closed-loop, with no emissions and no waste. There are no particular limitations on the separation processes involved, as long as propane, H2O, CO2, recycled hydrogen and liquid hydrocarbons (target hydrocarbons) are separated from the products.

[0040] The carbon reduction unit receives carbon materials generated from methane cracking in the methane cracking hydrogen production unit, as well as carbon dioxide tail gas generated during the hydrogenation reaction in the HEFA to SAF unit. The carbon dioxide tail gas undergoes a redox reaction with the carbon materials to convert them into carbon monoxide. This allows the carbon dioxide waste gas generated during the operation of the HEFA to SAF unit to react with the solid carbon material (C), a byproduct of methane cracking, in the carbon reduction unit (1000-1500℃), converting the carbon dioxide waste gas into more economically valuable CO, thus avoiding the direct emission of CO2 and its environmental impact.

[0041] The carbon reduction unit is preferably a fluidized bed reactor, and the reaction is carried out under normal pressure / slight negative pressure at a reaction temperature of 1000 ℃–1500 ℃. The heat required for the reaction is preferably obtained from the high-temperature exhaust gas containing CO2 generated by coal combustion or biomass waste co-firing.

[0042] In practice, the mixing unit receives carbon monoxide generated in the carbon reduction unit and another portion of hydrogen generated in the methane cracking hydrogen production unit, and mixes them to obtain syngas. By adjusting the mixing ratio of H2 and CO, syngas with different hydrogen-to-carbon ratios are generated for co-production of methanol, FT-SAF and other products.

[0043] The valuable products that can ultimately be obtained from this embodiment include: SAF - sustainable aviation fuel, and syngas with an adjustable hydrogen-to-carbon ratio.

[0044] In some embodiments, the temperature of the hydrogen generated in the methane cracking hydrogen production unit can reach 600 ℃-1200 ℃, while the temperature required for the hydrodeoxygenation and hydrocracking / isomerization reactions of renewable oils is below 450 ℃; therefore, before the hydrogen generated in the methane cracking hydrogen production unit is introduced into the HEFA to SAF production unit to participate in the reaction, the process further includes: Hydrogen generated in the methane cracking hydrogen production unit is introduced into the second heat exchange unit to exchange heat with the renewable oil. After the renewable oil is heated to the temperature required for hydrodeoxygenation and hydrocracking / isomerization reactions, it is then transported to the HEFA to SAF production unit along with a portion of the hydrogen to participate in the reaction. In this embodiment, the waste heat of the hydrogen is used to heat the renewable oil participating in the hydrodeoxygenation and hydrocracking / isomerization reactions, so that its temperature reaches the temperature required for these reactions. Then, it is transported to the HEFA to SAF production unit along with a portion of the hydrogen to participate in the reaction, which can further realize the cascade recovery and utilization of heat. This allows the HEFA to SAF production process to successfully complete the conversion of renewable oil without the need for additional heat source.

[0045] To enable those skilled in the art to more clearly understand the present invention, the following embodiments will be used to provide a detailed description of a methane cracking hydrogen production coupled with HEFA to produce SAF.

[0046] Example 1 System Composition See appendix Figure 2 Mainly includes: HEFA SAF production unit: The following components are connected in sequence: filtration unit, heating unit, hydrodeoxygenation (HDO) reactor, propane removal unit, gas-liquid separation unit, hydrocracking reactor, and fractionation unit; Methane cracking hydrogen production unit: methane cracking fluidized bed reactor; Carbon reduction (CO2 resource recovery) unit: Carbon reduction fixed-bed reactor; First heat exchange unit: The carbon monoxide generated in the carbon reduction unit exchanges heat with the methane feed gas.

[0047] The second heat exchange unit uses hydrogen generated in the methane cracking hydrogen production unit to preheat the renewable oil feedstock.

[0048] reaction raw materials Waste cooking oil (catering waste oil): acid value 2.5 mgKOH / g, water content 0.3 wt%, solid impurities 0.5 wt%; Biomethane: A product of anaerobic digestion and purification of organic waste, with a purity of 96 vol%, CO2 < 3 vol%, and H2S < 20 ppm; High-temperature exhaust gas: flue gas from biomass co-firing boiler, temperature 1200 ℃, CO2 concentration 18 vol%, O2 < 1 vol.

[0049] process See Figure 4 The diagram shows the material and energy flow in the methane cracking to hydrogen coupled with HEFA to SAF process. The explanation of the material and energy flow involved in the methane cracking to hydrogen coupled with HEFA to SAF process is as follows: Solid black line (material flow): Waste cooking oil → filtration → heating → HDO → propane removal → gas-liquid separation → hydrocracking → fractionation → SAF; Methane → cracking → H2 / C → carbon reduction → H2 → syngas; CO2 → carbon reduction → CO → syngas; Red dashed line (waste heat utilization): Methane cracking H2 → preheating feedstock oil; Blue dashed line (H2 supply flow): Methane cracking H2 → HDO / hydrocracking; Orange dashed line (CO2 flow): High-temperature tail gas containing CO2 at 1000-1500 ℃ → carbon reduction; CO2 obtained by gas-liquid separation after hydrogenation and deoxygenation at ~420 ℃ → carbon reduction.

[0050] Green dashed line (heat flow): 1000-1500 ℃ high-temperature exhaust gas containing CO2 → maintain carbon reduction reaction at 800 ℃.

[0051] Step 1: Methane cracking reaction for hydrogen production Preheated biomethane enters a methane cracking fluidized bed reactor, which is loaded with 200-600 μm biochar catalyst. The process conditions controlled during the reaction include: an average reaction temperature of 857℃, a pressure of 0.2 MPa, and a methane mean space velocity of 15000 h⁻¹. -1 The methane conversion rate was 92%, the produced hydrogen gas had a purity of 95 vol, and the byproduct was solid biochar (C).

[0052] The hydrogen obtained from pyrolysis can be cooled by heat exchange in the second heat exchange unit for waste heat recovery; and purified to 99.9 vol% by pressure swing adsorption (PSA) and transported to the HDO and hydrocracking units to achieve self-sufficiency in hydrogen without the need to purchase hydrogen from outside; the by-product solid biochar is directly transported to the carbon reduction unit (without additional separation, simplifying the process).

[0053] Step 2: Hydrogenation of renewable oils (1) Pretreatment and preheating of waste cooking oil Waste cooking oil first enters a 100 μm precision filtration unit to remove solid impurities, with the impurity content after filtration being <0.01wt%. It then enters the HEFA to SAF production unit, where the waste heat from the high-temperature hydrogen produced by the methane cracking hydrogen production unit (the waste heat flow shown by the red dotted line in the figure) is used to preheat the waste cooking oil, heating the raw oil to 420 ℃. No additional heat source is required, thus realizing the cascade utilization of waste heat.

[0054] (2) Hydrogenation Deoxygenation (HDO) Reaction The preheated feedstock oil is mixed with high-purity hydrogen produced by the methane cracking hydrogen production unit (blue dashed line H2 flow in the figure) and enters the HDO fixed-bed reactor. The reactor is loaded with a sulfide-state NiMo / Al2O3 catalyst (NiMo content 10-20 wt%). The process conditions controlled during the reaction include: an average bed temperature of 340℃, a pressure of 7 MPa, and a hydrogen-to-oil ratio of 1000 Nm. 3 / m 3 The main reaction includes the hydrogenation and deoxygenation of triglycerides, as shown in the following reaction formula: (C 17 H 35 COO)3C3H5+23H2→3C 17 H 36 +C3H8+3H2O; accompanied by decarboxylation / decarbonylation side reactions, producing CO2, CO, propane, and water.

[0055] The HDO product is fed into a propane removal unit (distillation column, operating pressure 1.2 MPa, top temperature 45 °C) to remove propane (92 vol%, LPG as a byproduct, which can be used as system fuel). The depropane-removed material then enters a high-pressure gas-liquid separation unit (operating pressure 6.8 MPa, temperature 180 °C), where the separated gaseous CO2 (91 vol%, purity) is directly fed to the carbon reduction unit, and the liquid phase consists of straight-chain n-alkanes (C6N2-C4 ... 15 -C 18 The main component (oxygen content <0.05 wt%) is transported to the hydrocracking unit.

[0056] (3) Hydrocracking / Isomerization reaction The high-purity hydrogen produced by the linear n-alkane and methane cracking hydrogen production unit continues to be fed into the hydrocracking fixed-bed reactor. The reactor is packed with a Pt / SAPO-11 bifunctional catalyst (Pt content 0.01-5 wt%, SAPO-11 silicon-aluminum ratio 0.15-0.3, specific surface area 50-400 m²). 2 / g), the process conditions controlled during the reaction include: an average bed temperature of 305℃, a pressure of 5.5 MPa, and a hydrogen-to-oil ratio of 600 Nm. 3 / m 3 Selective cracking and isomerization of long-chain straight-chain alkanes reduces C1 to C2. 15 -C 18 Straight-chain alkanes converted to C9-C 16 Isoalkanes.

[0057] The products from hydrocracking enter the fractionation unit (atmospheric and vacuum distillation column, operating pressure 0.15 MPa, top temperature 165 ℃, bottom temperature 300 ℃), from which SAF jet fuel fraction (boiling point 150-300 ℃, freezing point -52 ℃, flash point 42 ℃, density 805 kg / m³) is obtained. 3 The aromatic content is <5 vol%, smoke point 30 mm; the yield is 78 wt%, and the product conforms to ASTM D7566 standard.

[0058] Step 3: Carbon reduction reaction The carbon reduction unit involves materials from CO2 produced by gas-liquid separation in the HDO unit, solid C from methane cracking byproducts, and high-temperature tail gas at 1000-1500 ℃ (high-temperature tail gas containing CO2 produced by coal or biomass waste combustion, shown as the orange dashed line CO2 flow in the figure). These materials enter the carbon reduction fixed-bed reactor for oxidation-reduction reaction to produce carbon monoxide. The process conditions controlled during the reaction include: an average reaction temperature of 800 ℃, a pressure of 0.15 MPa, a C / CO2 molar ratio of 1.2:1, a CO2 conversion rate of 88%, and a CO purity of 90 vol.

[0059] The waste heat from the CO produced by the carbon reduction unit (red dotted line in the figure) is used entirely to preheat biomethane, realizing the cascade utilization of waste heat and reducing external heating to the system.

[0060] Step 4: Syngas Preparation The CO obtained from the carbon reduction unit is mixed with the residual H2 from the methane cracking hydrogen production unit in the mixing unit to produce syngas (H2:CO=1.2:1), which can be used for methanol synthesis, Fischer-Tropsch synthesis, etc.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0062] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0063] The foregoing has provided a detailed description of a methane cracking hydrogen production coupled with HEFA to SAF process and system provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only intended to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A methane cracking hydrogen production coupled with HEFA to SAF production system, characterized in that, include: The unit includes a methane cracking hydrogen production unit, an HEFA to SAF production unit, a carbon reduction unit, and a mixing unit. Among them, the methane cracking hydrogen production unit is used to catalytically crack methane to obtain hydrogen and carbon materials; The HEFA SAF production unit is connected to the methane cracking hydrogen production unit and is used to receive part of the hydrogen generated in the methane cracking hydrogen production unit. Using renewable oil as raw material, the renewable oil and the hydrogen undergo hydrodeoxygenation and hydrocracking / isomerization reactions under the action of a catalyst to convert them into renewable aviation fuel. The carbon reduction unit is connected to the HEFA-to-SAF unit and the methane cracking-to-hydrogen unit respectively, and is used to receive the carbon material generated in the methane cracking-to-hydrogen unit and the carbon dioxide tail gas generated when the HEFA-to-SAF unit undergoes hydrogenation reaction, so that the carbon dioxide tail gas reacts with the carbon material to undergo an oxidation-reduction reaction and be converted into carbon monoxide. The mixing unit is connected to both the carbon reduction unit and the methane cracking hydrogen production unit, and is used to receive carbon monoxide generated in the carbon reduction unit and another portion of hydrogen generated in the methane cracking hydrogen production unit, and mix them to obtain syngas.

2. The methane cracking hydrogen production coupled with HEFA to SAF system according to claim 1, characterized in that, The HEFA-to-SAF unit includes: a hydrodeoxygenation reactor and a hydrocracking reactor; The hydrodeoxygenation reactor is connected to the methane cracking hydrogen production unit and the carbon reduction unit respectively. The hydrodeoxygenation reactor is used to receive part of the hydrogen generated in the methane cracking hydrogen production unit and the renewable oil, so that the renewable oil and the hydrogen undergo a hydrodeoxygenation reaction to be converted into hydrocarbons and generate carbon dioxide tail gas which is then transported to the carbon reduction unit to participate in the redox reaction. The hydrocracking reactor is used to receive hydrocarbons generated in the hydrodeoxygenation reactor and a portion of the hydrogen generated in the methane cracking hydrogen production unit, so that the hydrocarbons and the hydrogen undergo a hydrocracking / isomerization reaction to be converted into the renewable aviation fuel.

3. The methane cracking hydrogen production coupled with HEFA to SAF system according to claim 1, characterized in that, The system further includes: a first heat exchange unit, which is connected to the methane cracking hydrogen production unit, the carbon reduction unit, and the mixing unit. The first heat exchange unit is used to receive carbon monoxide generated in the carbon reduction unit and methane feed gas, so that the methane feed gas and the carbon monoxide exchange heat. After the temperature of the methane feed gas reaches the temperature required for the cracking reaction, it is then transported to the methane cracking hydrogen production unit to participate in the reaction. The carbon monoxide, after being cooled by heat exchange, is transported to the mixing unit to participate in the preparation of syngas.

4. The methane cracking hydrogen production coupled with HEFA to SAF system according to claim 1 or 2, characterized in that, The system further includes a second heat exchange unit, which is connected to the methane cracking hydrogen production unit, the HEFA-to-SAF unit, and the mixing unit. The second heat exchange unit receives hydrogen generated in the methane cracking hydrogen production unit and exchanges heat with the renewable oil to bring the temperature of the renewable oil and hydrogen to a preset temperature. Then, the renewable oil and a portion of the hydrogen are transported to the HEFA-to-SAF unit to participate in hydrodeoxygenation and hydrocracking / isomerization reactions, and the remaining hydrogen is transported to the mixing unit for syngas production.

5. A process for producing SAF from methane through cracking and coupling with HEFA, characterized in that, The process is applicable to the system described in any one of claims 1-4, and includes: Methane is fed into a methane cracking hydrogen production unit, where it undergoes a catalytic cracking reaction to produce hydrogen and carbon materials. The renewable oil and a portion of the hydrogen are introduced into the HEFA-to-SAF unit. Under the action of a catalyst, the renewable oil undergoes hydrodeoxygenation and hydrocracking / isomerization reactions to be converted into renewable aviation fuel. The carbon dioxide tail gas generated during the hydrodeoxygenation reaction of the carbon material and the renewable oil is passed into the carbon reduction unit for mixing, so that the carbon material and the carbon dioxide tail gas undergo an oxidation-reduction reaction and are converted into carbon monoxide. The carbon monoxide and another portion of the hydrogen generated in the methane cracking hydrogen production unit are then mixed in a mixing unit to obtain syngas.

6. The methane cracking to hydrogen production coupled with HEFA to SAF process according to claim 5, characterized in that, Before the methane participating in the catalytic cracking reaction is introduced into the methane cracking hydrogen production unit, the process further includes: The methane and carbon monoxide generated in the carbon reduction unit are passed into the first heat exchange unit for heat exchange, so that the temperature of the methane feed gas reaches the temperature required for the cracking reaction. Then, it is sent to the methane cracking hydrogen production unit to participate in the reaction. The carbon monoxide that has been cooled by heat exchange is sent to the mixing unit to participate in the preparation of the synthesis gas.

7. The methane cracking to hydrogen production coupled with HEFA to SAF process according to claim 5 or 6, characterized in that, The catalyst used in the catalytic cracking reaction is selected from biochar materials with a diameter of 200 μm to 600 μm.

8. The methane cracking to hydrogen production coupled with HEFA to SAF process according to claim 5, characterized in that, Before the hydrogen generated by the catalytic cracking reaction is introduced into the HEFA to SAF production unit to participate in the reaction, the process further includes: The hydrogen generated in the methane cracking hydrogen production unit is introduced into the second heat exchange unit to exchange heat with the renewable oil. After the renewable oil is heated to the temperature required for hydrodeoxygenation and hydrocracking / isomerization reaction, it is then transported together with some hydrogen to the HEFA to SAF production unit to participate in the reaction.

9. The methane cracking to hydrogen production coupled with HEFA to SAF process according to claim 5 or 8, characterized in that, The catalyst used for the hydrodeoxygenation reaction of the renewable oil is selected from nickel-molybdenum system catalysts, and the catalyst used for the hydrocracking / isomerization reaction is selected from molecular sieve catalysts.

10. The methane cracking to hydrogen production coupled with HEFA to SAF process according to claim 1, characterized in that, The carbon material undergoes an oxidation-reduction reaction with the carbon dioxide exhaust gas to convert it into carbon monoxide. The heat of reaction includes high-temperature exhaust gas containing CO2 generated from coal combustion or co-firing of biomass waste.

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