System for preparing carbon-neutral aviation kerosene from carbon-rich natural gas and operation method of system

Abstract

The invention provides a system for preparing carbon neutral aviation kerosene from carbon-rich natural gas and an operation method thereof, and relates to the technical field of aviation kerosene, the system comprises a purification unit, a reforming reaction unit, a cooling unit, a pressurization unit, a Fischer-Tropsch reaction unit and a product separation unit which are connected in sequence; wherein the purification unit is used for dehydration, heavy hydrocarbon separation, desulfurization and demercuration of carbon-rich natural gas; the reforming reaction unit is used for performing methane-carbon dioxide dry reforming reaction; the Fischer-Tropsch reaction unit is used for converting the carbon-rich synthesis gas into aviation kerosene through Fischer-Tropsch synthesis; the product separation unit comprises a hot high-pressure separation unit, a cold high-pressure separation unit, a tail gas absorption unit and a regeneration unit. According to the invention, the carbon-rich natural gas can be directly converted into an aviation kerosene product with a high added value, and a carbon-rich natural gas decarburization link and a synthesis gas decarburization link in a traditional process are also ingeniously bypassed, so that the production process is greatly simplified, and the overall efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation kerosene, and particularly to a system for preparing carbon-neutral aviation kerosene from rich-carbon natural gas and an operation method thereof. Background Art

[0002] The CO2-CH4 dry reforming technology provides a technical route for converting two difficult-to-activate resources, CH4 and CO2, which has important practical significance and economic value for the efficient utilization of carbonaceous resources and the reduction of carbon emissions.

[0003] The prior art CN116947619A discloses a process and system for producing acetic acid from rich-methane gas through dry reforming and hydroformylation. The process includes the following steps: (1) purifying the rich-methane gas to obtain a purified feed gas; (2) subjecting part or all of the purified feed gas and carbon dioxide to a methane-carbon dioxide dry reforming reaction to obtain reformed syngas, and then separating carbon dioxide from the reformed syngas to obtain carbon dioxide-removed syngas; (3) extracting carbon monoxide from the carbon dioxide-removed syngas to obtain carbon monoxide-lean syngas and carbon monoxide-rich syngas, subjecting the carbon monoxide-lean syngas to a methanol synthesis reaction, and after the reaction, separating and purifying methanol to obtain refined methanol; (4) mixing the carbon monoxide-rich syngas with the refined methanol obtained in step (3) and then performing a hydroformylation reaction to generate a crude acetic acid product, and then purifying the crude acetic acid product to obtain an acetic acid product. This device provides a new idea for the conversion and utilization of rich-carbon natural gas. However, it should be noted that although carbon dioxide does not need to be removed in advance when rich-carbon natural gas is reformed to syngas, carbon dioxide in the reformed syngas still needs to be removed before subsequent hydroformylation, which increases the operating cost. How to directly convert rich-carbon natural gas into high-value chemicals and fuels without going through a decarbonization step is a current research hotspot.

[0004] Aviation kerosene is mainly composed of long-chain hydrocarbons, and the carbon chain lengths of these hydrocarbons are usually between C8 and C18, while the ideal carbon chain length is in the range of C8 to C16. In the current energy system, hydrocarbon liquid fuels derived from petroleum play a crucial role. However, green jet fuel is mainly obtained through the cracking-refining process of bio-oils, and its main cost lies in the large-scale collection of oil-containing biomass, which affects its large-scale application. The rich-carbon syngas obtained from rich-carbon natural gas can be used to prepare carbon-neutral or green aviation kerosene through Fischer-Tropsch synthesis. The liquid fuels produced through the Fischer-Tropsch synthesis route are characterized by being sulfur- and nitrogen-free and are environmentally friendly fuels.

[0005] It is particularly worth noting that, as an endothermic reaction process, the methane-carbon dioxide dry reforming technology requires operation under high-temperature and low-pressure conditions to ensure the effective progress of the reaction. In contrast, the Fischer-Tropsch reaction needs to be carried out under high-pressure conditions to successfully achieve its chemical conversion. Therefore, how to cleverly connect these two reaction steps in series to form an efficient and continuous process flow has become a hot topic and a difficult point in the current research and application fields.

[0006] By combining the design of a new catalyst, the present invention reduces the step of removing carbon dioxide from the carbon-rich syngas obtained by the dry reforming reaction, directly conducts the Fischer-Tropsch reaction on the carbon-rich syngas, and reduces the reaction process; by using supergravity strengthening to absorb, regenerate, and reuse the carbon dioxide generated by the Fischer-Tropsch synthesis unit, the present invention reduces the carbon emissions of the entire process and can produce carbon-neutral aviation kerosene or green aviation kerosene.

[0007] In view of this, the present invention is specifically proposed. Summary of the Invention

[0008] One of the objectives of the present invention is to provide a system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas, which can achieve direct conversion from raw materials to products, not only saving energy and costs, but also reducing environmental pollution, and opening up a new path for the production of aviation kerosene.

[0009] Another objective of the present invention is to provide an operating method for a system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas, which can directly convert carbon-rich natural gas into aviation kerosene in one step, avoiding the storage of the intermediate product carbon dioxide-rich syngas, and being beneficial to saving investment and reducing production costs.

[0010] The third objective of the present invention is to achieve the preparation of carbon-neutral aviation kerosene or green aviation kerosene with no carbon dioxide emissions throughout the process by reducing the decarbonization process of carbon-rich natural gas, the decarbonization process of carbon-rich syngas, and adding a supergravity enhanced absorption and regeneration unit for tail gas.

[0011] To achieve the above objectives of the present invention, the following technical solutions are specifically adopted:

[0012] In the first aspect, a system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas includes a purification unit, a reforming reaction unit, a cooling unit, a pressurization unit, a Fischer-Tropsch reaction unit, and a product separation unit connected in sequence;

[0013] The purification unit is used for dehydrating, separating heavy hydrocarbons, desulfurizing, and removing mercury from carbon-rich natural gas;

[0014] The reforming reaction unit is used for carrying out the methane-carbon dioxide dry reforming reaction;

[0015] The Fischer-Tropsch reaction unit is used to convert syngas rich in carbon into aviation kerosene through Fischer-Tropsch synthesis;

[0016] The product separation unit includes a hot high-pressure separator unit, a cold high-pressure separator unit, a tail gas absorption unit, and a regeneration unit.

[0017] Furthermore, a preheating and gasification unit is also provided between the purification unit and the reforming reaction unit;

[0018] Preferably, the preheating and gasification unit includes a gasification device and a preheating furnace;

[0019] Preferably, the gasification device is used to heat and gasify the raw material water;

[0020] Preferably, the preheating furnace is used to preheat the raw material gas and steam.

[0021] Furthermore, the reaction pressure of the reforming reaction unit is 1 MPa to 3 MPa, and the reaction temperature is 600 °C to 1000 °C.

[0022] Furthermore, the catalyst used in the reforming reaction unit includes a carrier, an active component, and an alkaline oxide promoter;

[0023] Preferably, the carrier is at least one of silica and alumina;

[0024] Preferably, the active component includes Ni;

[0025] Preferably, the alkaline oxide promoter includes at least one of MgO, CaO, BaO, and La2O3.

[0026] Furthermore, the Ni content in the catalyst is 1 wt% to 20 wt%, preferably 5 wt% to 15 wt%;

[0027] Preferably, the carrier content in the catalyst is 80 wt% to 99 wt%, preferably 85 wt% to 95 wt%;

[0028] Preferably, the alkaline oxide promoter content in the catalyst is 1 wt% to 10 wt%, preferably 0.5 wt% to 5 wt%.

[0029] Furthermore, the cooling unit includes air cooling, water cooling, and a dryer, and is used to cool the product and remove water from the product.

[0030] Furthermore, the pressurizing unit includes a mixing tank and an air compressor;

[0031] Preferably, the mixing tank is used to mix the product of the reforming reaction unit with hydrogen to form a mixed gas;

[0032] Preferably, the air compressor is used to increase the pressure of the mixed gas.

[0033] Furthermore, the reaction temperature of the Fischer-Tropsch reaction unit is 280°C to 360°C, the reaction pressure is 2.0 MPa to 5.0 MPa, and the reaction space velocity is 1000 h -1 ~15000 h -1 .

[0034] Furthermore, the catalyst used in the Fischer-Tropsch reaction unit is a composite metal oxide;

[0035] Preferably, based on the total mass of metal elements, the composite metal oxide contains 40% to 70% of Fe, 5% to 20% of Mn, and 5% to 20% of K;

[0036] Preferably, the tail gas absorption unit includes a rotating packed bed absorber that uses amine solution for decarbonization;

[0037] Preferably, the regeneration unit includes a rotating packed bed desorber for carbon dioxide regeneration;

[0038] Preferably, after carbon dioxide regeneration in the regeneration unit, it enters the dry reforming reaction device and / or the Fischer-Tropsch synthesis device according to requirements.

[0039] In a second aspect, a method for operating the system according to any one of the above, includes the following steps:

[0040] Using rich-carbon natural gas as a raw material, and sequentially processing it through each unit to obtain carbon-neutral aviation kerosene.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] The system for preparing carbon-neutral aviation kerosene from rich-carbon natural gas provided by the present invention eliminates the decarbonization link of rich-carbon natural gas, which is beneficial for energy conservation and consumption reduction. It directly converts the rich-carbon syngas produced by dry reforming, avoiding the transportation and storage links, and realizes the high-value utilization of rich-carbon natural gas with a high CO2 content. In addition, through the rotating packed bed enhanced tail gas absorption unit and regeneration unit, the reuse of carbon dioxide in the product is realized, and the carbon emission reduction effect is obvious. In short, the system of the present invention can directly convert rich-carbon natural gas into high-value aviation kerosene products, and at the same time cleverly bypasses the essential decarbonization links of rich-carbon natural gas and syngas in the traditional process, thus greatly simplifying the production process and improving the overall efficiency. At the same time, the raw material type adaptability of the system of the present invention is strong, and it is applicable to gas sources containing two greenhouse gases, methane and carbon dioxide, such as coke oven gas, rich-carbon natural gas, biogas, shale gas, coalbed methane, and industrial off-gas, which is beneficial for improving the utilization value of carbon dioxide-rich natural gas.

[0043] The operation method of the system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas provided by the present invention can directly convert carbon-rich natural gas into aviation kerosene in one step, avoiding the storage of the intermediate product of syngas rich in carbon dioxide, which is beneficial to saving investment and reducing production costs. Detailed Embodiments

[0044] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are some of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0045] According to the first aspect of the present invention, a system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas is provided, which includes a purification unit, a reforming reaction unit, a cooling unit, a pressurization unit, a Fischer-Tropsch reaction unit, and a product separation unit connected in sequence;

[0046] The purification unit is used for dehydrating, separating heavy hydrocarbons, desulfurizing, and removing mercury from carbon-rich natural gas;

[0047] The reforming reaction unit is used for carrying out the dry reforming reaction of methane-carbon dioxide;

[0048] The Fischer-Tropsch reaction unit is used for converting carbon-rich syngas into aviation kerosene through Fischer-Tropsch synthesis;

[0049] The product separation unit includes a hot high-pressure separator unit, a cold high-pressure separator unit, a tail gas absorption unit, and a regeneration unit.

[0050] It should be noted that the effluent from the Fischer-Tropsch reaction unit enters the hot high-pressure separator unit for gas-liquid two-phase separation. The gas separated from the top is cooled by a cooler and then enters the cold high-pressure separator unit. The heavy product separated from the bottom is controlled by a control loop composed of a liquid level sensor and a liquid level regulating valve to control the liquid level and then enters the heavy oil product tank. The light components of oil, water, and gas are further separated into light oil components, water, and non-condensable gas in the cold high-pressure separator unit.

[0051] In the present invention, carbon-rich natural gas refers to natural gas with a CO2 volume fraction > 20%. Other low-carbon alkanes containing CO2 of the same type as carbon-rich natural gas are also applicable to the system of the present invention, such as coalbed methane, coal pyrolysis gas (coke oven gas), and gasification gas containing CO2 made from coal or biomass.

[0052] The system of the present invention eliminates the decarbonization link of carbon-rich natural gas, which is beneficial to energy conservation and consumption reduction. It directly converts the carbon-rich syngas produced by dry reforming, avoiding the transportation and storage links, realizing the high-value utilization of carbon-rich natural gas with a high CO2 content, and having obvious carbon emission reduction effects.

[0053] In summary, the system of the present invention can directly convert rich-carbon natural gas into high-value aviation kerosene products, and at the same time cleverly bypasses the essential carbon dioxide removal links for rich-carbon natural gas and syngas in the traditional process, thus greatly simplifying the production process and improving the overall efficiency.

[0054] In a preferred embodiment, a preheating and gasification unit may also be provided between the purification unit and the reforming reaction unit.

[0055] The preheating and gasification unit includes, but is not limited to, a gasification device and a preheating furnace. The gasification device is used for heating and gasifying the raw water, and the preheating furnace is used for preheating the raw gas and water vapor.

[0056] In a preferred embodiment, the reaction pressure of the reforming reaction unit can be 1 MPa to 3 MPa, and its typical but non-limiting pressures are, for example, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa. The reaction temperature can be 600 °C to 1000 °C, and its typical but non-limiting temperatures are, for example, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C.

[0057] In the present invention, the catalyst used in the reforming reaction unit includes, but is not limited to, a carrier, an active component, and an alkaline oxide promoter; among them, the carrier can be one or several of silica and alumina, the active component can be Ni, and the alkaline oxide promoter can be one or several of metal oxides such as MgO, CaO, BaO, and La2O3; it can be prepared by the equal-volume impregnation method.

[0058] In a preferred embodiment, the Ni content in the catalyst used in the reforming reaction unit can be 1 wt% to 20 wt%, and can be further preferably 5 wt% to 15 wt%; the carrier content can be 80 wt% to 99 wt%, and can be further preferably 85 wt% to 95 wt%; the alkaline oxide promoter content can be 1 wt% to 10 wt%, and can be further preferably 0.5 wt% to 5 wt%.

[0059] It should be noted that the catalyst in the reforming reaction unit needs to be reduced before use, and the reduction operation conditions are as follows: Using H2, N2, or a mixture of H2 and N2 as the reducing gas, the volume ratio of H2 and N2 in the mixture is 1 to 100:100, and the volume space velocity of the reducing gas is 0.5 min –1 ~5 min –1 , the reduction temperature is 200 °C to 600 °C, and the reduction time is 1 h to 6 h.

[0060] In a preferred embodiment, the cooling unit includes, but is not limited to, air cooling, water cooling, and a dryer, and is used for cooling the product and removing water from the product.

[0061] In a preferred embodiment, the pressurizing unit includes, but is not limited to, a mixing tank and an air compressor. The mixing tank is used to mix the product of the reforming reaction unit with hydrogen to form a mixed gas, and the air compressor is used to increase the pressure of the mixed gas.

[0062] In the present invention, the reaction temperature of the Fischer-Tropsch reaction unit can be 280 °C to 360 °C, and its typical but non-limiting temperatures are, for example, 280 °C, 290 °C, 300 °C, 320 °C, 340 °C, 360 °C. The reaction pressure can be 2.0 MPa to 5.0 MPa, and its typical but non-limiting pressures are, for example, 2.0 MPa, 3.0 MPa, 4.0 MPa, 5.0 MPa. The reaction space velocity can be 1000 h -1 ~15000 h -1 , and its typical but non-limiting reaction space velocities are, for example, 1000 h -1 , 2000 h -1 , 3000 h -1 , 4000 h -1 , 5000 h -1 , 6000 h -1 , 7000 h -1 , 8000 h -1 , 9000 h -1 , 10000 h -1 , 13000 h -1 , 15000 h -1 .

[0063] It should be noted that the catalyst used in the Fischer-Tropsch reaction unit can be a composite metal oxide. Based on the total mass of the metal elements, the composite metal oxide contains 40% to 70% of Fe, 5% to 20% of Mn, and 5% to 20% of K. The iron-manganese-potassium catalyst, i.e., the composite metal oxide, can be prepared by microwave-assisted heating and solution combustion synthesis method;

[0064] The catalyst in the Fischer-Tropsch reaction needs to be reduced before use. A mixed gas of H2, N2, or H2 and N2, or H2 and CO can be used as the reducing atmosphere. The volume ratio range of H2 and N2, as well as H2 and CO in the mixed gas, can be 1 to 100:100. The volume space velocity of the reducing gas can be 0.5 min –1 ~5 min –1 , the reduction temperature can be 320 °C to 380 °C, and the reduction time can be 16 h to 24 h.

[0065] In the present invention, the tail gas absorption unit can be a rotating packed bed absorber using amine solution for decarbonization, and the regeneration unit can be a rotating packed bed desorber for carbon dioxide regeneration. After the carbon dioxide is regenerated in the regeneration unit, it can enter the dry reforming reaction device and / or the Fischer-Tropsch synthesis device according to requirements.

[0066] According to a second aspect of the present invention, there is provided a method for operating the system according to any one of the above, comprising the following steps:

[0067] Using rich-carbon natural gas as a raw material, it is sequentially processed through each unit to obtain carbon-neutral aviation kerosene.

[0068] The operation method of the system of the present invention can directly convert rich-carbon natural gas into aviation kerosene in one step, avoiding the storage of the intermediate product rich-carbon dioxide syngas, which is beneficial to saving investment and reducing production costs.

[0069] The present invention will be further described below through examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0070] Example 1

[0071] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silicon dioxide and stir for 2 h. Then dry the obtained solution at 120 °C for 12 h, and finally calcine the dried catalyst in a muffle furnace at 500 °C for 12 h to obtain catalyst A;

[0072] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 h. Then add tartaric acid to the solution, stir for 1 h under the condition of a water bath at 50 °C, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and program the temperature to 350 °C for roasting for 4 h to obtain catalyst B;

[0073] (3) After pressing and crushing catalyst A and B to 20 - 30 mesh, mix and dilute them with 20 - 30 mesh quartz sand in a ratio of 1:1, and then load them into the reforming reaction unit and the Fischer-Tropsch synthesis unit of the device respectively. The loading amount of the catalyst is 1 g; Reduce catalyst A under a hydrogen atmosphere at a temperature of 600 °C and a flow rate of 20 mL·min –1 for 6 h, and reduce catalyst B under an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0074] (4) After the rich-carbon syngas is dehydrated, heavy hydrocarbon separated, desulfurized, and demercured, it enters the reforming reaction unit and reacts at 750 °C, atmospheric pressure, and a space velocity of 30000 h -1 ; At the same time, the rich-carbon dioxide syngas generated by the reaction is directly cooled and dried and then enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 5000 h -1, and then supplemented to the Fischer-Tropsch reaction unit by an air compressor, at 2.0 MPa, 320 °C, 4000 h -1 for reaction.

[0075] Example 2

[0076] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silica and stir for 2 h. Then dry the obtained solution at 120 °C for 12 h, and finally put the dried catalyst into a muffle furnace and calcine it at 500 °C for 12 h to obtain catalyst A;

[0077] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 hour. Then add tartaric acid to the solution, stir for 1 hour under the condition of a water bath at 50 °C, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 minutes, and then transfer it to a muffle furnace and program the temperature to 350 °C and calcine it for 4 hours to obtain catalyst B;

[0078] (3) After pressing and crushing catalyst A and B to 20-30 mesh, mix and dilute them with 20-30 mesh quartz sand in a ratio of 1:1, and then load them into the reforming reaction unit and Fischer-Tropsch synthesis unit of the device respectively. The loading amount of the catalyst is 1 g; Reduce catalyst A in a hydrogen atmosphere at a temperature of 600 °C and a flow rate of 20 mL·min –1 for 6 h, and reduce catalyst B in an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0079] (4) After dehydration, heavy hydrocarbon separation, desulfurization, and mercury removal of the carbon-rich syngas, it enters the reforming reaction unit and reacts at 750 °C, atmospheric pressure, and a space velocity of 20000 h -1 ; At the same time, the carbon dioxide-rich syngas generated by the reaction is directly cooled and dried and then enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 3700 h -1 , and then supplemented to the Fischer-Tropsch reaction unit by an air compressor, at 2.0 MPa, 320 °C, 4000 h -1 for reaction.

[0080] Example 3

[0081] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silica and stir for 2 h. Then dry the obtained solution at 120 °C for 12 h, and finally put the dried catalyst into a muffle furnace and calcine it at 500 °C for 12 h to obtain catalyst A;

[0082] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 hour. Then add tartaric acid to the solution. Under the condition of a water bath at 50 °C, after stirring for 1 h, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and raise the temperature programatically to 350 °C for calcination for 4 h to obtain catalyst B;

[0083] (3) Press tablets of catalyst A and B and crush them to 20 - 30 mesh. After mixing and diluting them with 20 - 30 mesh quartz sand in a ratio of 1:1, respectively load them into the reforming reaction unit and the Fischer-Tropsch synthesis unit of the device. The loading amount of the catalyst is 1 g; Reduce catalyst A under a hydrogen atmosphere at a temperature of 600 °C and a hydrogen flow rate of 20 mL·min –1 for 6 h, and reduce catalyst B under an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0084] (4) After the carbon-rich syngas is dehydrated, heavy hydrocarbon separated, desulfurized, and demercured, it enters the reforming reaction unit and reacts at 750 °C, atmospheric pressure, and a space velocity of 10000 h -1 . Meanwhile, the carbon dioxide-rich syngas generated by the reaction is directly cooled and dried and then enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 2500 h -1 , and then it is supplemented to the Fischer-Tropsch reaction unit by an air compressor and reacts at 2.0 MPa, 320 °C, and 4000 h -1 ;

[0085] Example 4

[0086] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silicon dioxide and stir for 2 h. Then dry the obtained solution at 120 °C for 12 h, and finally put the dried catalyst into a muffle furnace and calcine it at 500 °C for 12 h to obtain catalyst A;

[0087] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 h. Then add tartaric acid to the solution. Under the condition of a water bath at 50 °C, after stirring for 1 h, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and raise the temperature programatically to 350 °C for calcination for 4 h to obtain catalyst B;

[0088] (3) After pressing and crushing catalyst A and B to 20 - 30 mesh, they are mixed and diluted with 20 - 30 mesh quartz sand in a ratio of 1:1, and then respectively loaded into the reforming reaction unit and the Fischer - Tropsch synthesis unit of the device. The loading amount of the catalyst is 1 g; Catalyst A is reduced in a hydrogen atmosphere at a temperature of 600 °C and a flow rate of 20 mL·min –1 for 6 h, and catalyst B is reduced in an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0089] (4) After the carbon - rich syngas is dehydrated, heavy hydrocarbon separated, desulfurized and de - mercuryed, it enters the reforming reaction unit and reacts at 750 °C, atmospheric pressure, and a space velocity of 5000 h -1 ; Meanwhile, the carbon - dioxide - rich syngas generated by the reaction is cooled and dried and then directly enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 1200 h -1 , and then it is supplemented to the Fischer - Tropsch reaction unit through an air compressor and reacts at 2.0 MPa, 320 °C, and 4000 h -1 .

[0090] Example 5

[0091] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silica and stir for 2 h. Then the obtained solution is dried at 120 °C for 12 h, and finally the dried catalyst is placed in a muffle furnace and calcined at 500 °C for 12 h to obtain catalyst A;

[0092] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 hour. Then add tartaric acid to the solution, stir for 1 h under the condition of a water bath at 50 °C, transfer it to a porcelain crucible, heat it in a microwave - assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and program - raise the temperature to 350 °C and calcine for 4 h to obtain catalyst B;

[0093] (3) After pressing and crushing catalyst A and B to 20 - 30 mesh, they are mixed and diluted with 20 - 30 mesh quartz sand in a ratio of 1:1, and then respectively loaded into the reforming reaction unit and the Fischer - Tropsch synthesis unit of the device. The loading amount of the catalyst is 1 g; Catalyst A is reduced in a hydrogen atmosphere at a temperature of 600 °C and a flow rate of 20 mL·min –1 for 6 h, and catalyst B is reduced in an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0094] (4) After the carbon-rich syngas is dehydrated, heavy hydrocarbons are separated, desulfurized, and demercurized, it enters the reforming reaction unit and reacts at 750 °C, atmospheric pressure, and a space velocity of 1000 h -1 ; Meanwhile, the carbon dioxide-rich syngas generated by the reaction is directly cooled and dried and then enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 1200 h -1 , and then it is supplemented to the Fischer-Tropsch reaction unit through an air compressor and reacts at 2.5 MPa and 4000 h -1 .

[0095] Example 6

[0096] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silica and stir for 2 h. Then dry the obtained solution at 120 °C for 12 h, and finally calcine the dried catalyst in a muffle furnace at 500 °C for 12 h to obtain catalyst A;

[0097] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 hour. Then add tartaric acid to the solution. Under the condition of a water bath at 50 °C, stir for 1 h, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and program the temperature to 350 °C for roasting for 4 h to obtain catalyst B;

[0098] (3) After pressing and crushing catalyst A and B to 20-30 mesh, mix and dilute them with 20-30 mesh quartz sand in a ratio of 1:1, and then load them into the reforming reaction unit and Fischer-Tropsch synthesis unit of the device respectively. The loading amount of the catalyst is 1 g; Reduce catalyst A in a hydrogen atmosphere at a temperature of 600 °C and a flow rate of 20 mL·min –1 for 6 h, and reduce catalyst B in an atmosphere at a temperature of 600 °C, CO / H2 = 1 / 2 (volume ratio), and a flow rate of 20 mL·min –1 for 6 h;

[0099] (4) After the carbon-rich syngas is dehydrated, heavy hydrocarbons are separated, desulfurized, and demercurized, it enters the reforming reaction unit and reacts at 725 °C, atmospheric pressure, and a space velocity of 5000 h -1 ; Meanwhile, the carbon dioxide-rich syngas generated by the reaction is directly cooled and dried and then enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 1200 h -1 , and then it is supplemented to the Fischer-Tropsch reaction unit through an air compressor and reacts at 2.5 MPa, 320 °C, and 4000 h -1 .

[0100] Example 7

[0101] (1) Dissolve Ni(NO3)2·6H2O and La(NO3)3·6H2O in water, then add silicon dioxide and stir for 2 h. After that, dry the obtained solution at 120 °C for 12 h. Finally, put the dried catalyst into a muffle furnace and calcine it at 500 °C for 12 h to obtain catalyst A;

[0102] (2) Dissolve Fe(NO3)3·9H2O, Mn(NO3)2·9H2O, and KNO3 in water and stir for 1 hour. Then add tartaric acid to the solution. Under the condition of a water bath at 50 °C, stir for 1 h, transfer it to a porcelain crucible, heat it in a microwave-assisted chemical reactor for 30 min, and then transfer it to a muffle furnace and raise the temperature to 350 °C for calcination for 4 h to obtain catalyst B;

[0103] (3) Press tablets of catalyst A and B and crush them to 20 - 30 mesh. Mix and dilute them with 20 - 30 mesh quartz sand in a ratio of 1:1, and then load them into the reforming reaction unit and the Fischer-Tropsch synthesis unit of the device respectively. The loading amount of the catalyst is 1 g; Reduce catalyst A in a hydrogen atmosphere at a temperature of 600 °C and a hydrogen flow rate of 20 mL·min –1 for 6 h, and reduce catalyst B in a hydrogen atmosphere at a temperature of 600 °C and a hydrogen flow rate of 20 mL·min –1 for 6 h;

[0104] (4) After the carbon-rich syngas is dehydrated, heavy hydrocarbon separated, desulfurized, and demercured, it enters the reforming reaction unit and reacts at 700 °C, atmospheric pressure, and a space velocity of 5000 h -1 ; At the same time, the carbon dioxide-rich syngas generated by the reaction is cooled and dried and then directly enters the mixing unit to be mixed with hydrogen in a mixing tank. The flow rate of hydrogen is 1200 h -1 , and then it is supplemented to the Fischer-Tropsch reaction unit by an air compressor and reacts at 2.5 MPa, 320 °C, and 4000 h -1 .

[0105] The catalyst evaluation of each example is shown in Table 1 in detail.

[0106] Table 1

[0107]

[0108] According to the results of the catalyst performance evaluation, in the reforming reaction unit, reducing the space velocity or increasing the temperature can both improve the conversion rates of CO2 and CH4. While in the Fischer-Tropsch reaction unit, increasing the pressure helps to promote the conversion of carbon-rich syngas and simultaneously increase the yield of the aviation kerosene fraction; The system for preparing aviation kerosene from carbon-rich natural gas of the present invention can achieve the direct conversion of methane and carbon dioxide. Under the optimized reaction conditions, the selectivity of this system for aviation kerosene exceeds 55%.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for preparing carbon-neutral aviation kerosene from carbon-rich natural gas, characterized in that, It includes a purification unit, a reforming reaction unit, a cooling unit, a pressurizing unit, a Fischer-Tropsch reaction unit, and a product separation unit that are connected in sequence; The purification unit is used for dehydration, heavy hydrocarbon separation, desulfurization, and mercury removal of rich-carbon natural gas; The reforming reaction unit is used for carrying out methane-carbon dioxide dry reforming reaction; The Fischer-Tropsch reaction unit is used for converting rich-carbon syngas into aviation kerosene through Fischer-Tropsch synthesis; The product separation unit includes a hot high-pressure separator unit, a cold high-pressure separator unit, a tail gas absorption unit, and a regeneration unit.

2. The system according to claim 1, wherein A preheating and gasification unit is also provided between the purification unit and the reforming reaction unit; Preferably, the preheating and gasification unit includes a gasification device and a preheating furnace; Preferably, the gasification device is used for heating and gasifying raw water; Preferably, the preheating furnace is used for preheating raw gas and steam.

3. The system according to claim 1 or 2, characterized in that, The reaction pressure of the reforming reaction unit is 1 MPa to 3 MPa, and the reaction temperature is 600 °C to 1000 °C.

4. The system according to claim 3, wherein The catalyst used in the reforming reaction unit includes a carrier, an active component, and an alkaline oxide promoter; Preferably, the carrier is at least one of silica and alumina; Preferably, the active component includes Ni; Preferably, the alkaline oxide promoter includes at least one of MgO, CaO, BaO, and La₂O₃.

5. The system according to claim 4, wherein The Ni content in the catalyst is 1 wt% to 20 wt%, preferably 5 wt% to 15 wt%; Preferably, the carrier content in the catalyst is 80 wt% to 99 wt%, preferably 85 wt% to 95 wt%; Preferably, the alkaline oxide promoter content in the catalyst is 1 wt% to 10 wt%, preferably 0.5 wt% to 5 wt%.

6. The system according to claim 1 or 2, characterized in that, The cooling unit includes air cooling, water cooling, and a dryer, and is used for cooling the product and removing water from the product.

7. The system according to claim 1 or 2, characterized in that, The pressurizing unit includes a mixing tank and an air compressor; Preferably, the mixing tank is used for mixing the product of the reforming reaction unit with hydrogen to form a mixed gas; Preferably, the air compressor is used for increasing the pressure of the mixed gas.

8. The system according to claim 1 or 2, characterized in that, The reaction temperature of the Fischer-Tropsch reaction unit is 280°C to 360°C, the reaction pressure is 2.0 MPa to 5.0 MPa, and the reaction space velocity is 1000 h -1 ~15000 h -1 .

9. The system according to claim 1 or 2, characterized in that, The catalyst used in the Fischer-Tropsch reaction unit is a composite metal oxide; Preferably, based on the total mass of metal elements, Fe accounts for 40% to 70%, Mn accounts for 5% to 20%, and K accounts for 5% to 20% in the composite metal oxide; Preferably, the tail gas absorption unit includes a rotating packed bed absorber using amine liquid for decarbonization; Preferably, the regeneration unit includes a rotating packed bed desorber for carbon dioxide regeneration; Preferably, after carbon dioxide regeneration in the regeneration unit, it enters the dry reforming reaction device and / or the Fischer-Tropsch synthesis device according to requirements.

10. A method for operating the system according to any one of claims 1-9, characterized in that, It includes the following steps: Using rich-carbon natural gas as a raw material, it is sequentially processed through each unit to obtain carbon-neutral aviation kerosene.

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