Method for preparing sustainable aviation fuel from biogas through reforming and Fischer-Tropsch reaction

Abstract

The invention discloses a method for preparing aviation kerosene from biogas through reforming and Fischer-Tropsch reaction. The method comprises the following steps: firstly, reforming the biogas and water vapor into synthesis gas on a Ni / MgO-Al2O3 catalyst; then preparing aviation kerosene through Fischer-Tropsch synthesis on a Co-molecular sieve bifunctional catalyst; and then C1-C7 low-carbon chain hydrocarbon generated by Fischer-Tropsch synthesis enters a reforming cycle. According to the bifunctional catalyst in the Fischer-Tropsch synthesis process, cobalt acid salt and organic alkaline quaternary ammonium salt in molecular sieve synthesis react to generate TPACoO2, TEACoO2 or TMACoO2 through an acid-base pair strategy, and meanwhile, the quaternary ammonium salt is a template agent in molecular sieve synthesis, so that Co can be directionally packaged in a molecular sieve. According to the synthesis method, the size and dispersity of the Co active phase can be controlled, meanwhile, due to the influence of pore channels and acidity of the molecular sieve, synthesis gas can be converted into aviation kerosene (C8-C16) in a high-selectivity mode, and meanwhile the isomerization degree of paraffin is improved. The invention develops a new route for preparing high-quality aviation kerosene from biogas.

Description

Technical Field

[0001] The present application belongs to the field of bio-jet fuel preparation, and specifically relates to a method for preparing aviation fuel by reforming biogas and Fischer-Tropsch reaction, and a catalyst system for the corresponding reaction process. Background Art

[0002] With the continuous growth of global energy demand and the increasing awareness of environmental protection, finding clean and efficient alternative energy has become an important issue in the energy field. As the main fuel for the aviation industry, the quality of aviation kerosene (abbreviated as "jet kerosene") directly affects the operating efficiency of aircraft and environmental protection. At present, the production method of aviation kerosene mainly uses non-renewable fossil energy as raw materials and distills crude oil. This method is heavily dependent on petroleum resources. Fischer-Tropsch synthesis technology is a non-petroleum route that uses synthesis gas (CO and H2) as raw materials and converts it into high-value hydrocarbons, such as olefins, aromatics and liquid fuels. Based on this, through the Fischer-Tropsch synthesis technology, synthesis gas can be efficiently converted into jet kerosene, which can reduce my country's dependence on petroleum resources and is suitable for my country's energy structure characteristics of "rich in coal, poor in oil, and little gas".

[0003] However, the selectivity of traditional Fischer-Tropsch synthesis products is limited by the Anderson-Schulz-Flory (ASF) distribution, which means that the theoretical selectivity of aviation kerosene is less than 40%. Therefore, how to break through the ASF distribution limitation of traditional Fischer-Tropsch synthesis to improve the selectivity of aviation kerosene is one of the most challenging goals. For example, Chinese patent CN1 17732502A introduces a method for preparing a catalyst for preparing aviation kerosene from synthesis gas, in which ZSM-5 molecular sieve is ion-exchanged with ammonium nitrate, and then loaded with cobalt with a mass fraction of 6% to obtain a Co / HZSM-5 catalyst. The experimental results show that the carbon monoxide conversion rate is above 70%, while the selectivity is around 30%.

[0004] In order to solve the above problems, domestic and foreign researchers have carried out a lot of research work to explore the modification methods of Fischer-Tropsch synthesis of aviation kerosene. Among them, bifunctional catalysts have become one of the hot topics in the field of Fischer-Tropsch synthesis. Bifunctional catalysts have significant structural sensitivity. The active metal size, carrier pore structure, acidity and other factors have an important influence on the CO conversion rate and its product selectivity. So far, researchers have been trying to break the traditional ASF product distribution law and improve the C8-C 16Selectivity. Among them, Toyama University once adopted the method of adding olefins in the reactor to make the product distribution move toward aviation kerosene (J. Li, Y Yoneyama, T. Vitidsant, G. Yang, N. Tsubaki, Fuel, 2016, 171: 159-166) to improve selectivity. However, this method requires specific instruments and equipment, is not conducive to fixed bed reaction, and is difficult to industrialize. Chinese patent CN110368983A discloses a method for preparing a catalyst for preparing aviation kerosene from synthesis gas. The invention patent contains: (A) 1 to 50 weight % of elements selected from Ru, Fe, Ni, Co, Pt, and Pd as catalytic active components, (B) 1 to 20 weight % of elements in the lanthanide series as catalytic aids, and carbon carriers. However, the dispersibility of the catalytic active components of this technology is poor, and the conversion rate of CO is low. This description will provide a new method for preparing aviation kerosene from biogas with high selectivity through reforming and Fischer-Tropsch reaction. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a green and economical method for producing aviation kerosene (C8-C 16 The method comprises: reforming biogas into synthesis gas on a Ni / MgO-Al2O3 catalyst; secondly, producing aviation kerosene through Fischer-Tropsch synthesis on a Co-molecular sieve bifunctional catalyst; and then reforming and recycling C1-C7 low-carbon chain hydrocarbons. The process is green and economical, and the catalyst used has high activity, high stability and high selectivity, and has the advantages of mild reaction conditions, strong applicability and low cost.

[0006] The production of aviation kerosene from biogas is carried out in a fixed-bed reactor. First, the biogas (CO2 and CH4) is coupled with steam reforming to synthesis gas over a Ni / MgO-Al2O3 catalyst, and then aviation kerosene is obtained through Fischer-Tropsch synthesis over a Co-based catalyst, while low-carbon hydrocarbons are circulated and reformed.

[0007] The technical solution adopted in this application is: a method for producing aviation kerosene from biogas. First, reforming is carried out on a Ni / MgO-Al2O3 catalyst; then aviation kerosene is obtained through Fischer-Tropsch synthesis. The catalyst for Fischer-Tropsch synthesis uses ZSM-5, BETA or Y molecular sieve as the main carrier and Co as the main active center. The metal in the lanthanide element is used as an additive,

[0008] The following three factors are used to jointly promote and improve the catalytic activity and selectivity of the catalyst in the Fischer-Tropsch synthesis process.

[0009] First, through the "acid-base pair strategy" to CoO2 -Coordinate with quaternary ammonium salt cation TPA+ to stabilize Co. At the same time, alkaline quaternary ammonium salt is also a template required for molecular sieve synthesis, which can encapsulate Co metal in the molecular sieve framework in a directional manner;

[0010] Secondly, the size and dispersion of the Co active phase can be controlled through solid phase transformation of the seed, and the silanol groups on the surface of the carrier further assist the dispersion of the metal.

[0011] Third, by introducing lanthanide additives into the molecular sieve through ion exchange, the acidity of the molecular sieve can be regulated, the cracking of long-chain alkanes can be promoted, and a high conversion rate and high selectivity of Fischer-Tropsch jet fuel fraction can be achieved.

[0012] The technical solutions for achieving the above-mentioned purpose of the present invention can be summarized as follows:

[0013] 1. A method for producing aviation kerosene (C8-C8) by coupling biogas reforming with Fischer-Tropsch synthesis as claimed in claim 1. 16 The method is characterized in that the reforming is carried out in a fixed bed reaction, characterized in that the reaction temperature is 650-1200°C, the optimal temperature is 800-850°C; the reaction space velocity is 10000-50000mL / g cat ·h, the optimal space velocity is 40000-50000mL / g cat ·h. The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor; the reaction temperature is 150-350°C, the optimum temperature is 180-250°C; the reaction space velocity is 2000-10000mL / g cat ·h, the optimal space velocity is 2000-5000mL / g cat ·h; the molar ratio of H2 / CO can be 1-3, preferably 1-2; the reaction pressure is 1-3MPa, preferably 2-3MPa.

[0014] 2. A method for producing aviation kerosene (C8-C 16 The invention discloses a method for preparing a Co-based catalyst for the synthesis of hydrocarbons (chain alkanes), characterized in that: CO2 and low-carbon alkanes are reformed into synthesis gas using Ni / MgO-Al2O3 as a catalyst, and then the synthesis gas is directly and highly selectively converted into aviation kerosene fraction hydrocarbons under the catalytic action of a Co-based bifunctional catalyst, and the low-carbon hydrocarbons are cyclically reformed at the same time. The method for preparing the Co-based bifunctional catalyst in this process is characterized in that an "acid-base pair strategy" is adopted, and the steps are as follows:

[0015] (1) Cobaltate and the organic alkaline quaternary ammonium salt in the synthesis of molecular sieves are coordinated by the "acid-base pair strategy" and stirred at room temperature for a period of time until it becomes clear to obtain solution A;

[0016] (2) adding the seed crystals of the molecular sieve to be synthesized, as well as the required silicon source, aluminum source, water and sodium hydroxide to solution A, and then stirring until the water is completely evaporated to obtain powder B;

[0017] (3) Mixing the powder B and SiO2 in a mortar to obtain powder C;

[0018] (4) Then, the powder C is crystallized at a certain temperature for a period of time by using a dry gel conversion method, and finally washed, dried and calcined to obtain powder D;

[0019] (5) The metal of the lanthanide series is introduced as a catalyst promoter through ion exchange, and finally calcined in air to obtain the desired catalyst.

[0020] 3. According to the synthesis method of the Co-based catalyst, based on the total weight of the catalyst, the catalyst comprises:

[0021] (1) Co active centers with an atomic weight of 1-30 wt%, and optimal conditions of 10-20 wt%;

[0022] (2) a lanthanide additive in an amount of 1-15 wt % by atomic weight, preferably 1-5 wt % by atomic weight;

[0023] (3) 65-95 wt%, most preferably 80-85 wt% of the carrier.

[0024] 4. The method according to item 1-2 is characterized in that, step (1): the coordination of cobaltate and alkaline quaternary ammonium salt is TPACoO2, TEACoO2 or TMACoO2, and the best is TPACoO2 or TEACoO2; wherein the molar ratio of quaternary ammonium salt to cobaltate is 1-5, preferably 1-2; and the stirring time is 4-8 hours, and the best is 4-6 hours.

[0025] 5. The method according to any one of items 1 to 3, characterized in that in step (2): the added seed crystals are ZSM-5, BETA or Y molecular sieve, preferably BETA or Y seed crystals.

[0026] 6. The method according to any one of items 1 to 4, characterized in that, in step (3), the SiO2 is one or both of white carbon black and nano-SiO2, preferably white carbon black.

[0027] 7. The method according to any one of items 1 to 5, characterized in that step (4): the temperature of the dry glue conversion is 100-200° C., most preferably 150-180° C., and the time is 1-5 days, most preferably 2-3 days.

[0028] 8. The method according to any one of items 1 to 6 is characterized in that, in step (5), the metal additive in the lanthanide element can be one or two of La, Ce, and Gd, and La or Ce is most preferred; wherein the concentration of lanthanide ions during the ion exchange process is 0.1-5.0 mol / L, preferably 0.3-1.0 mol / L; the reaction temperature during the ion exchange process is 50-200°C, preferably 70-90°C; the ion exchange time is 5-15 hours, preferably 10-12 hours; after the ion exchange, calcination is performed at 450-600°C for 2-6 hours, and most preferably 500-550°C for 4-5 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 . Flowchart of preparing sustainable aviation fuel through biogas reforming and Fischer-Tropsch reaction. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0031] Example 1.

[0032] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0033] A certain amount of nickel nitrate, aluminum nitrate and magnesium nitrate hydrate was dissolved in an appropriate amount of deionized water to form solution A, and a certain amount of anhydrous citric acid was dissolved in an appropriate amount of deionized water to form solution B. The molar ratio of the metal loading to the citric acid was ensured to be 2, and then the B solution was added to the A solution to form the final mixed solution C. The C solution was stirred at 85°C for 7h to obtain a viscous gel, which was then dried at 120°C for 24h and finally calcined at 600°C for 4h in a muffle furnace to obtain the Ni / MgO-Al2O3 catalyst.

[0034] (2) Preparation of Co-based bifunctional catalysts

[0035] Dissolve 2.9 g of sodium cobaltate and 20.4 mL of TPAOH (25 wt%) in 5 mL of deionized water and stir until clear to obtain solution A;

[0036] 5.0 g of ZSM-5 seed crystals, 2.430 g of tetraethyl orthosilicate, 0.125 g of aluminum isopropoxide, 10 mL of deionized water and 0.03 g of sodium hydroxide were added to solution A, and the mixture was stirred for 6 h and dried in an oven at 100 °C for 12 h to obtain powder B;

[0037] 2.0 g of the powder B and 0.5 g of white carbon black were mixed in a mortar to obtain powder C;

[0038] Then, powder C was crystallized at 180°C for 3 days using a dry gel conversion method (the lower layer was deionized water), and then washed to pH = 7, dried, and calcined in air at 550°C for 5 h to remove the template, to obtain powder D;

[0039] 1 g of powder D was added to a lanthanum nitrate solution (0.2 mol / L, 100 mL) and stirred at 80° C. for 12 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired Co-based catalyst.

[0040] (3) Catalyst performance test

[0041] Biogas reforming is carried out in a fixed bed reactor. Weigh 0.1g of catalyst and mix it evenly with 0.5g of quartz sand of 40-60 mesh, then load it into the reactor. After reducing it at 700℃ for 2h, switch to nitrogen and cool it to 450℃, then switch to biogas for reforming reaction, the reaction temperature is 850℃, and the pressure is normal pressure. The conversion rate of CH4 and CO2 in biogas exceeds 98%, and the selectivity of CO and H2 is close to 100%.

[0042] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst (40-60 mesh) is weighed and then loaded into the reactor. The temperature is raised to 400 °C at 2 °C / min under a 100 mL / min H2 atmosphere and maintained for 8 h. The reaction temperature is then lowered to 200 °C and the reformed synthesis gas (100 mL / min) is switched to the Fischer-Tropsch reaction at a pressure of 2 MPa. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0043] Example 2.

[0044] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0045] The preparation of Ni / MgO-Al2O3 catalyst in (1) Example 1 was repeated.

[0046] (2) Preparation of Co-based bifunctional catalysts

[0047] 2.9 g of sodium cobaltate and 20.4 mL of TEAOH (25 wt%) were dissolved in 5 mL of deionized water and stirred until clear to obtain solution A;

[0048] 5.0 g of BETA seed crystals, 2.430 g of tetraethyl orthosilicate, 0.125 g of aluminum isopropoxide, 10 mL of deionized water and 0.03 g of sodium hydroxide were added to solution A, and the mixture was stirred for 6 h and dried in an oven at 100 °C for 12 h to obtain powder B;

[0049] 2.0 g of the powder B and 0.5 g of white carbon black were mixed in a mortar to obtain powder C;

[0050] Then, powder C was crystallized at 180°C for 3 days using a dry gel conversion method (the lower layer was deionized water), and then washed to pH = 7, dried, and calcined in air at 550°C for 5 h to remove the template, to obtain powder D;

[0051] 1 g of powder D was added to a lanthanum nitrate solution (0.2 mol / L, 100 mL) and stirred at 80° C. for 12 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired Co-based catalyst.

[0052] (3) Catalyst performance test

[0053] The biogas reforming catalyst reduction and reaction steps in Example 1 were repeated.

[0054] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst (40-60 mesh) is weighed and then loaded into the reactor. The temperature is raised to 400 °C at 2 °C / min under a 100 mL / min H2 atmosphere and maintained for 8 h. The temperature is then lowered to 150 °C and the reformed synthesis gas (100 mL / min) is switched to the Fischer-Tropsch reaction at a pressure of 2 MPa. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0055] Example 3.

[0056] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0057] The preparation of Ni / MgO-Al2O3 catalyst in (1) Example 1 was repeated.

[0058] (2) Preparation of Co-based bifunctional catalysts

[0059] Dissolve 2.9 g of potassium cobaltate and 20.4 mL of TMAOH (25 wt%) in 5 mL of deionized water and stir until clear to obtain solution A;

[0060] 5.0 g of Y seed crystals, 2.430 g of tetraethyl orthosilicate, 0.25 g of aluminum isopropoxide, 10 mL of deionized water and 0.03 g of sodium hydroxide were added to solution A, and the mixture was stirred for 6 h and dried in an oven at 100 °C for 12 h to obtain powder B;

[0061] Mix 2.0 g of the powder B and 0.5 g of nano-SiO2 in a mortar to obtain powder C.

[0062] Then, powder C was crystallized at 150°C for 2 days using a dry gel conversion method (the lower layer was deionized water), and then washed to pH = 7, dried, and calcined in air at 550°C for 5h to remove the template, to obtain powder D;

[0063] 1 g of powder D was added to a lanthanum nitrate solution (0.4 mol / L, 100 mL) and stirred at 80° C. for 12 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired Co-based catalyst.

[0064] (3) Catalyst performance test

[0065] The biogas reforming catalyst reduction and reaction steps in Example 1 were repeated.

[0066] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst and 1.5 g of quartz sand (40-60 mesh) are weighed and then loaded into the reactor. The temperature is raised to 400 °C at 2 °C / min under a 100 mL / min H2 atmosphere and maintained for 8 h. The reaction temperature is then lowered to 250 °C. At the same time, the reformed synthesis gas (80 mL / min) is switched to the Fischer-Tropsch reaction at a pressure of 3 MPa. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0067] Example 4.

[0068] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0069] The preparation of Ni / MgO-Al2O3 catalyst in (1) Example 1 was repeated.

[0070] (2) Preparation of Co-based bifunctional catalysts

[0071] 5.0 g of Y seed crystals, 2.430 g of tetraethyl orthosilicate, and 0.250 g of sodium aluminate were added to 20 mL of deionized water, stirred for 6 h, and then statically crystallized in an oven at 120 ° C for 48 h, then filtered and washed to neutrality, dried at 80 ° C for 12 h, and finally calcined at 550 ° C for 5 h to obtain powder A;

[0072] 1 g of powder A was added to a lanthanum nitrate solution (0.8 mol / L, 100 mL), and stirred at 80° C. for 4 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired La-Y molecular sieve.

[0073] A certain amount of Co(NO3)2·6H2O was weighed and dissolved in 20 mL of deionized water, and then 1 g of La-Y molecular sieve was added to obtain a 15% Co / La-Y bifunctional catalyst.

[0074] (3) Catalyst performance test

[0075] The biogas reforming catalyst reduction and reaction steps in Example 1 were repeated.

[0076] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst and 1.5 g of quartz sand (40-60 mesh) are weighed and then loaded into the reactor. The temperature is raised to 450 °C at 2 °C / min under a 50 mL / min H2 atmosphere and maintained for 4 h. The reaction temperature is then lowered to 220 °C. At the same time, the reformed synthesis gas (80 mL / min) is switched to the Fischer-Tropsch reaction at a pressure of 1 MPa. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0077] Example 5.

[0078] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0079] The preparation of Ni / MgO-Al2O3 catalyst in (1) Example 1 was repeated.

[0080] (2) Preparation of Co-based bifunctional catalysts

[0081] 5.0 g of BETA seed, 20.4 mL of TEAOH (25 wt%), 2.430 g of tetraethyl orthosilicate, 0.125 g of aluminum isopropoxide and 0.03 g of sodium hydroxide were added to 10 mL of deionized water, stirred for 6 h, and then statically crystallized in an oven at 140 ° C for 48 h, then filtered and washed to neutrality, dried at 80 ° C for 12 h, and finally calcined at 550 ° C for 5 h to obtain powder A;

[0082] 1 g of powder A was added to a gadolinium nitrate solution (0.8 mol / L, 100 mL), and stirred at 80° C. for 12 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired Gd-BETA molecular sieve.

[0083] A certain amount of Co(NO3)2·6H2O was weighed and dissolved in 20 mL of deionized water, and then 1 g of Gd-BETA molecular sieve was added to obtain a 15% Co / Gd-BETA bifunctional catalyst.

[0084] (3) Catalyst performance test

[0085] The biogas reforming catalyst reduction and reaction steps in Example 1 were repeated.

[0086] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst and 1.5 g of quartz sand (40-60 mesh) are weighed and then loaded into the reactor. The temperature is raised to 450 °C at 2 °C / min under a 50 mL / min H2 atmosphere and maintained for 4 h. The reaction temperature is then lowered to 220 °C. At the same time, the reformed synthesis gas (80 mL / min) is switched to the Fischer-Tropsch reaction at a pressure of 1 MPa. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0087] Example 6.

[0088] (1) Preparation of Ni / MgO-Al2O3 catalyst

[0089] The preparation of Ni / MgO-Al2O3 catalyst in (1) Example 1 was repeated.

[0090] (2) Preparation of Co-based bifunctional catalysts

[0091] 5.0 g ZSM-5 seed crystals, 2.430 g tetraethyl orthosilicate, 20.4 mL TPAOH (25 wt%), 0.125 g aluminum isopropoxide and 0.03 g sodium hydroxide were dissolved in 10 mL deionized water, stirred for 6 h, and then statically crystallized in an oven at 180 ° C for 48 h, then filtered and washed to neutrality, dried at 80 ° C for 12 h, and finally calcined at 550 ° C for 5 h to obtain powder A;

[0092] 1 g of powder A was added to a cerium nitrate solution (1 mol / L, 100 mL), and stirred at 80° C. for 4 h, followed by filtration, drying, and calcination at 550° C. in air for 4 h to obtain the desired Ce-ZSM-5 molecular sieve.

[0093] A certain amount of Co(NO3)2·6H2O was weighed and dissolved in 20 mL of deionized water, and then 1 g of Ce-ZSM-5 molecular sieve was added to obtain a 15% Co / Ce-ZSM bifunctional catalyst.

[0094] (3) Catalyst performance test

[0095] The biogas reforming catalyst reduction and reaction steps in Example 1 were repeated.

[0096] The Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor. 1.5 g of catalyst and 1.5 g of quartz sand (40-60 mesh) are weighed and then loaded into the reactor. The temperature is raised to 400 °C at 2 °C / min under a 100 mL / min H2 atmosphere and maintained for 8 h. The temperature is then lowered to 150 °C and switched to reformed synthesis gas (50 mL / min) at a pressure of 1 MPa. The temperature is then raised to 200 °C for Fischer-Tropsch reaction. Finally, the aviation kerosene fraction (C8-C 16 ), low carbon hydrocarbons cyclic reforming. The conversion rate and selectivity test results are shown in Table 1.

[0097] Table 1 Test results of the reaction performance of biogas to prepare aviation kerosene by Fischer-Tropsch synthesis

[0098]

[0099] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the rights of the present application.

Claims

1. A method for preparing aviation kerosene (C8-C 16 A method for producing a paraffinic hydrocarbon, characterized in that Reforming is carried out in a fixed bed reaction, characterized by a reaction temperature of 650-1200°C, an optimum temperature of 800-850°C, and a reaction space velocity of 10000-50000 mL / g cat ·h, the optimal space velocity is 40000-50000mL / g cat ·h; Fischer-Tropsch synthesis of aviation kerosene is carried out in a fixed bed reactor; the reaction temperature is 150-350°C, the optimal temperature is 180-250°C; the reaction space velocity is 2000-10000mL / g cat ·h, the optimal space velocity is 2000-5000mL / g cat ·h; the molar ratio of H2 / CO can be 1-3, preferably 1-2; the reaction pressure is 1-3MPa, preferably 2-3MPa.

2. A method for preparing aviation kerosene (C8-C 16 A method for preparing a paraffin) is characterized in that: Using Ni / MgO-Al2O3 as catalyst, CO2 and methane in biogas are reformed into synthesis gas through dry reforming coupled with steam reforming. Then, the synthesis gas is directly and highly selectively converted into aviation kerosene fraction hydrocarbons under the catalytic action of Co-based bifunctional catalyst, and low-carbon hydrocarbons enter the cyclic reforming: (1) The Co-based catalyst uses 1-30 wt% of one or more of lithium cobaltate, potassium cobaltate, and sodium cobaltate as the Co source. (2) Using one or more of ZSM-5, BETA, and Y molecular sieves as carriers, (3) Using one or more metals from the lanthanide series as catalyst promoters.

3. A method for preparing a Co-based catalyst for producing aviation kerosene by Fischer-Tropsch synthesis as claimed in claim 2, characterized in that: Using the "acid-base pair strategy", the steps are as follows: (1) Cobaltate and the organic alkaline quaternary ammonium salt used in the synthesis of molecular sieves are coordinated by the "acid-base pair strategy" and stirred at room temperature for a period of time until the solution becomes clear, thereby obtaining solution A; (2) adding the seed crystals of the molecular sieve to be synthesized, as well as the required silicon source, aluminum source, water and sodium hydroxide to solution A, and then stirring until the water is completely evaporated to obtain powder B; (3) Mixing the powder B and SiO2 in a mortar to obtain powder C; (4) Then, the powder C is crystallized at a certain temperature for a period of time by using a dry gel conversion method, and finally washed, dried and calcined to obtain powder D; (5) The metal of the lanthanide series is introduced as a catalyst promoter through ion exchange, and finally calcined in air to obtain the desired catalyst.

4. The method according to claim 3, wherein the catalyst comprises, based on the total weight of the catalyst: (1) Co active centers with an atomic weight of 1-30 wt%, and optimal conditions of 10-20 wt%; (2) a lanthanide additive in an amount of 1-15 wt % by atomic weight, preferably 1-5 wt % by atomic weight; (3) 65-95 wt%, most preferably 80-85 wt% of the carrier.

5. The method according to claim 3, characterized in that: Step (1): The coordination of the cobaltate and the alkaline quaternary ammonium salt is TPACoO2, TEACoO2 or TMACoO2, and the best is TPACoO2 or TEACoO2; wherein the molar ratio of the quaternary ammonium salt to the cobaltate is 1-5, preferably 1-2; and the stirring time is 4-8 hours, and the best is 4-6 hours.

6. The method according to claim 2, characterized in that Step (2): The added seed crystals are ZSM-5, BETA or Y molecular sieve, preferably BETA or Y seed crystals.

7. The method according to claim 2, characterized in that Step (3): The SiO2 is one or both of white carbon black and nano-SiO2, preferably white carbon black.

8. The method according to claim 2, characterized in that Step (4): The temperature for the dry gel conversion is 100-200°C, most preferably 150-180°C, and the time is 1-5 days, most preferably 2-3 days.

9. The method according to claim 2, characterized in that: Step (5): the metal promoter in the lanthanide element can be one or two of La, Ce, and Gd, with La and Ce being most preferred; The concentration of lanthanide ions during the ion exchange process is 0.1-5 mol / L, preferably 0.3-1 mol / L; the reaction temperature during the ion exchange process is 50-200°C, preferably 70-90°C; the ion exchange time is 5-15 hours, preferably 10-12 hours; after the ion exchange, calcination is performed at 450-600°C for 2-6 hours, most preferably 500-550°C and 4-5 hours.

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