Mesoporous Y molecular sieve supported iron catalyst as well as preparation method and application thereof

Abstract

The invention discloses a mesoporous Y molecular sieve supported iron catalyst as well as a preparation method and application thereof. The catalyst is composed of a mesoporous Y molecular sieve carrier and an active component loaded on the surface of the mesoporous Y molecular sieve carrier, the active component comprises a metal carbide, a metal simple substance and a metal oxide; the metal comprises an iron element, a metal element A and a metal element B; the metal element A is selected from at least one of aluminum and / or transition metal; the metal element B is selected from at least one of alkali metal and / or alkaline earth metal.

Description

Technical Field

[0001] The present application relates to a mesoporous Y molecular sieve supported iron catalyst and a preparation method and application thereof, and belongs to the field of chemistry and chemical engineering. Background Art

[0002] The global aviation industry's carbon emissions account for 12% of emissions in the transportation sector and 2% of total carbon dioxide emissions. In the context of carbon neutrality, the international aviation industry has formulated an active carbon emission reduction plan. Compared with traditional jet fuel, sustainable aviation fuel (SAF) can reduce carbon dioxide emissions by 50% to 90% over its entire life cycle, and is the main technical route to achieve net zero emissions in the international aviation industry before 2050. As a high-cost technology, the promotion of SAF under the current situation cannot be separated from policy support. Europe and the United States have provided strong policy support for the SAF industry, making it the main production and consumption area of ​​SAF in the world. The European Union will take the lead in forcing airlines to use SAF from 2025. According to the "Regulation of the European Parliament and of the European Council on ensuring a fair competition environment for sustainable air transport" (ReFuelEUAviation Regulation) promulgated by the European Union in October 2023, from 2025, all flights departing from EU airports, regardless of their destination within or outside the EU, must use a fuel mixed with 2% SAF and traditional kerosene. By 2030, the proportion must reach 6%; by 2035, the proportion must reach 20%; by 2050, the proportion must reach 70%.

[0003] The Chinese SAF market is still in its early stages. The synthesis of aviation fuel from carbon dioxide hydrogenation is expected to achieve low-carbon or zero-carbon production, which has attracted great attention from various countries, and the pace of research and development demonstration has accelerated. The synthesis of aviation fuel from carbon dioxide and green hydrogen is a research and development direction that has received much attention among various SAF production processes. Tsinghua University has developed the world's leading technology for synthesizing aviation fuel from carbon dioxide and green hydrogen (CO2AF), which first uses synthesis gas to produce C8-C12 crude aviation fuel in one step, and then adds green hydrogen to produce aviation fuel products after reforming, with a product yield of 90%. This process is in the demonstration stage and has high prospects for technology promotion and commercial development. The direct hydrogenation of CO2 to prepare aviation kerosene or the hydrogenation of CO2 to prepare aviation kerosene via CO is one of the key technologies for the preparation of sustainable aviation kerosene, and the development of efficient catalysts can promote the industrialization of this technology. Summary of the invention

[0004] According to one aspect of the present application, a mesoporous Y molecular sieve supported iron catalyst is provided. The catalyst has high activity and high selectivity in the preparation of aviation kerosene by CO / CO2 hydrogenation, thereby improving the yield of aviation kerosene. The catalyst improves the utilization rate of the acidic sites and metal active sites of the molecular sieve, thereby adjusting the product distribution of Fischer-Tropsch synthesis and improving the selectivity of aviation kerosene.

[0005] According to one aspect of the present application, a mesoporous Y molecular sieve-supported iron catalyst is provided, wherein the mesoporous Y molecular sieve-supported iron catalyst is composed of a mesoporous Y molecular sieve carrier and an active component supported on the surface of the mesoporous Y molecular sieve carrier;

[0006] The active components include metal carbides, metal elements and metal oxides;

[0007] The metal includes iron element, metal element A and metal element B;

[0008] The metal element A is selected from at least one of aluminum and / or transition metals;

[0009] The metal element B is selected from at least one of alkali metals and / or alkaline earth metals;

[0010] In the mesoporous Y molecular sieve supported iron catalyst, the total amount of metal elements contained in the active component is 100wt%, wherein the content of iron element is 1-80wt%, the content of metal element A is 0.1-50wt%, and the content of metal element B is 0.01-40wt%.

[0011] In the mesoporous Y molecular sieve supported iron catalyst, the loading amount of active components is 1 to 80 wt%.

[0012] The mesoporous Y molecular sieve carrier is selected from at least one of USY molecular sieve and SSY molecular sieve;

[0013] The metal element A is selected from at least one of Mn, Co, Cu, Zn, Ti, Al, Cr, Ni, Ce, and Zr;

[0014] The metal element B is selected from at least one of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba.

[0015] According to another aspect of the present application, a method for preparing the above-mentioned mesoporous Y molecular sieve supported iron catalyst is provided, comprising the following steps:

[0016] (1) mixing a mesoporous Y molecular sieve carrier with a precipitant and an aqueous solution containing an iron source and a metal element A source, precipitating, filtering, and washing until the pH value of the filtrate is in the range of 6 to 8 to obtain a catalyst precursor;

[0017] (2) The catalyst precursor is immersed in an aqueous solution containing a metal element B source, dried, and calcined to obtain the mesoporous Y molecular sieve-supported iron catalyst.

[0018] The precipitant is selected from at least one of aqueous ammonia, aqueous sodium carbonate solution, aqueous potassium carbonate solution, and aqueous ammonium carbonate solution;

[0019] The concentration of the precipitant is 1 to 80 wt %;

[0020] The iron source is selected from at least one of ferric nitrate, ferric sulfate, ferric chloride, ferrous nitrate, ferrous chloride, and ferrous sulfate;

[0021] The metal element A source is selected from at least one of nitrates, chlorides and sulfates of Mn, Co, Cu, Zn, Ti, Al, Cr, Ni, Ce and Zr;

[0022] In the aqueous solution containing the iron source and the metal element A source, the concentration of the iron source is 1-80 wt %, and the concentration of the metal element A source is 1-50 wt %.

[0023] The precipitation temperature is 5 to 95°C;

[0024] The precipitation time is 0.5 to 100;

[0025] The pH of the precipitation is 7-11.

[0026] The metal element B source is selected from water-soluble metal salts of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba;

[0027] In the aqueous solution containing the metal element B source, the concentration of the metal element B source is 0.01 to 40 wt %;

[0028] The drying temperature is 5 to 150° C.

[0029] The drying time is 1 to 100 hours;

[0030] The calcination temperature is 150-1200°C;

[0031] Optionally, the calcination temperature is 150-1000°C;

[0032] Optionally, the calcination temperature is 200-1000°C;

[0033] The calcination time is 0.5 to 50 hours;

[0034] The calcination atmosphere is air atmosphere, oxygen-containing atmosphere, nitrogen atmosphere or inert gas atmosphere.

[0035] According to another aspect of the present application, a method for preparing aviation kerosene by hydrogenating CO / CO2 is provided, comprising the following steps:

[0036] The hydrogen and the raw material containing CO and / or CO2 are contacted with a catalyst to react and obtain aviation kerosene;

[0037] Wherein, the catalyst is the above-mentioned catalyst.

[0038] The reaction temperature is 150-450°C;

[0039] The reaction pressure is 0.1-8Mpa;

[0040] The volume ratio of the hydrogen to the raw material containing CO and / or CO2 is 0.2 to 8;

[0041] The total GHSV of the hydrogen and the raw materials containing CO and / or CO2 is 200 to 20000 h -1 .

[0042] The catalyst is reduced;

[0043] The reduction temperature is 200-650°C;

[0044] The reduction time is 1 to 50 hours;

[0045] The reducing atmosphere is a hydrogen atmosphere and / or a carbon monoxide atmosphere.

[0046] The beneficial effects of this application include:

[0047] 1) The mesoporous Y molecular sieve supported iron catalyst provided in the present application has high activity, high selectivity and high stability.

[0048] 2) The mesoporous Y molecular sieve supported iron catalyst provided in the present application effectively solves the problem of low selectivity of aviation kerosene in the preparation of aviation kerosene by hydrogenation of CO and CO2, and provides an effective way to increase the yield of aviation kerosene.

[0049] 3) The present application provides a method for preparing a mesoporous Y molecular sieve-loaded iron catalyst, which introduces metal nanoparticles / metal clusters into the molecular sieve by a precipitation precipitation method, so that the acidity of the catalyst molecular sieve and the metal active sites can effectively synergize and improve the selectivity of aviation kerosene.

[0050] 4) The mesoporous Y molecular sieve loaded iron catalyst provided in the present application can effectively improve the aviation kerosene selectivity in the preparation of aviation kerosene by hydrogenation of CO and CO2, improve the utilization rate of the acidic sites and metal active sites of the molecular sieve, thereby improving the catalytic activity, and also adjust the product distribution, thereby improving the aviation kerosene selectivity. DETAILED DESCRIPTION

[0051] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0052] In the embodiment, the reaction product is analyzed by online and offline gas chromatography. The gas chromatograph is Agilent's 7890A, and the detectors are TCD and FID. TCD analysis uses a packed column TDX-01 (2m×2mm), and the carrier gas is high-purity helium; FID analysis uses a capillary column HP-PLOT / Q (30m×0.32mm). The column temperature is programmed: the temperature is increased from 40°C to 150°C at a heating rate of 20°C / min, maintained for 5 minutes, and then increased to 240°C at a heating rate of 30°C / min, and maintained for 5 minutes.

[0053] Example 1 Preparation of catalyst samples

[0054] 5.5g of mesoporous Y molecular sieve, 20.0g of ferric nitrate nonahydrate and 10.1g of manganese nitrate hexahydrate were dissolved in 200ml of deionized water to obtain solution I. The precipitant was ammonia water with a mass percentage concentration of 25%. Solution I and the precipitant were continuously mixed in a parallel flow manner, and the mixing ratio was controlled to keep the solution pH at 7. The temperature during the coprecipitation process was kept at 20°C, and continuous stirring was performed during the precipitation process. After the coprecipitation was completed, it was aged at a temperature of 30°C for 10h, filtered, and washed with deionized water until neutral. 190g of a 1wt% potassium carbonate solution (solution II) was added to the filter cake and re-slurried to obtain mixture I. Mixture I was dried at a temperature of 50°C for 12h, and then calcined at a temperature of 500°C in an air atmosphere for 10h. The desired catalyst was obtained, which was recorded as sample C1 # .

[0055] Sample C2 # ~C15 # The specific preparation steps are the same as sample C1 # In the specific preparation, the Fe source in solution I, the type and amount of source A, the coprecipitation conditions, the amount of solution II and the concentration of source B are shown in Table 1. The drying, roasting and melting treatment conditions of mixture I are shown in Table 2. XRF was used to analyze the final sample C1. # ~C15 # The elemental composition was analyzed and the results are shown in Table 1.

[0056] Table 1 Catalyst preparation raw materials, coprecipitation conditions and elemental composition

[0057]

[0058]

[0059]

[0060] Table 2 Drying, calcination and melt processing conditions of mixture I

[0061]

[0062]

[0063] Example 2 Sample C1 # ~ Sample C15 # Reaction performance test of CO hydrogenation to prepare aviation kerosene

[0064] 2g of sample C1 # Load into the reaction tube, and combine with liner, quartz wool and quartz sand to keep the catalyst in a constant temperature zone. Load the reaction tube into a fixed bed device so that the thermocouple is located in the catalyst bed. Use H2 for reduction treatment, and the reduction conditions are: reduction temperature of 350°C, reduction at normal pressure, and reduction time of 6h. The reduced catalyst CO is hydrogenated to prepare aviation kerosene, and the reaction conditions are 350°C, reaction pressure of 4MPa, raw gas volume ratio H2 / CO=0.5, and space velocity GHSV=1000h -1 At the same time, the valve box temperature, pipeline insulation and chromatographic pipeline insulation were set to 150°C. The reaction products were detected online by chromatography every 30 minutes, and the liquid products were collected every 24 hours. The reaction time was 24 hours, the CO conversion rate was 97%, and the aviation kerosene selectivity was 85%.

[0065] The process of using other catalysts for CO hydrogenation to prepare aviation kerosene is similar. The specific reduction and reaction conditions are shown in Table 3, and the reaction results are shown in Table 4.

[0066] Table 3 Reduction and reaction conditions of CO hydrogenation to produce aviation kerosene

[0067]

[0068]

[0069] Table 4 CO hydrogenation to produce aviation kerosene reaction results

[0070]

[0071] Example 3 Sample C1 # ~ Sample C15 # Reaction performance test of CO2 hydrogenation to prepare aviation kerosene

[0072] The operation process of the CO2 hydrogenation reaction to prepare aviation kerosene is the same as that of the CO hydrogenation reaction to prepare aviation kerosene. The difference is that the reaction raw materials are CO2 and H2. The specific reduction and reaction conditions are shown in Table 5, and the reaction results are shown in Table 6.

[0073] Table 5 Reduction and reaction conditions of CO2 hydrogenation to produce aviation kerosene

[0074]

[0075]

[0076] Table 6 CO2 hydrogenation to produce aviation kerosene reaction results

[0077]

[0078] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A mesoporous Y molecular sieve supported iron catalyst, characterized in that: The mesoporous Y molecular sieve supported iron catalyst is composed of a mesoporous Y molecular sieve support and an active component supported on the surface of the mesoporous Y molecular sieve support; The active components include metal carbides, metal elements and metal oxides; The metal includes iron element, metal element A and metal element B; The metal element A is selected from at least one of aluminum and / or transition metals; The metal element B is selected from at least one of alkali metals and / or alkaline earth metals; In the mesoporous Y molecular sieve supported iron catalyst, the total amount of metal elements contained in the active component is 100wt%, wherein the content of iron element is 1-80wt%, the content of metal element A is 0.1-50wt%, and the content of metal element B is 0.01-40wt%. In the mesoporous Y molecular sieve supported iron catalyst, the loading amount of active components is 1 to 80 wt%.

2. The mesoporous Y molecular sieve supported iron catalyst according to claim 1, characterized in that: The mesoporous Y molecular sieve carrier is selected from at least one of USY molecular sieve and SSY molecular sieve; The metal element A is selected from at least one of Mn, Co, Cu, Zn, Ti, Al, Cr, Ni, Ce, and Zr; The metal element B is selected from at least one of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba.

3. A method for preparing a mesoporous Y molecular sieve supported iron catalyst according to any one of claims 1 or 2, characterized in that: The following steps are involved: (1) mixing a mesoporous Y molecular sieve carrier with a precipitant and an aqueous solution containing an iron source and a metal element A source, precipitating, filtering, and washing to obtain a catalyst precursor; (2) The catalyst precursor is immersed in an aqueous solution containing a metal element B source, dried, and calcined to obtain the mesoporous Y molecular sieve-supported iron catalyst.

4. The preparation method according to claim 3, characterized in that: The precipitant is selected from at least one of aqueous ammonia, aqueous sodium carbonate solution, aqueous potassium carbonate solution, and aqueous ammonium carbonate solution; The concentration of the precipitant is 1 to 80 wt %; The iron source is selected from at least one of ferric nitrate, ferric sulfate, ferric chloride, ferrous nitrate, ferrous chloride, and ferrous sulfate; The metal element A source is selected from at least one of nitrates, chlorides and sulfates of Mn, Co, Cu, Zn, Ti, Al, Cr, Ni, Ce and Zr; In the aqueous solution containing the iron source and the metal element A source, the concentration of the iron source is 1-80 wt %, and the concentration of the metal element A source is 1-50 wt %.

5. The preparation method according to claim 3, characterized in that: The precipitation temperature is 5 to 95°C; The precipitation time is 0.5 to 100; The pH of the precipitation is 7-11.

6. The preparation method according to claim 3, characterized in that: The metal element B source is selected from water-soluble metal salts of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba; In the aqueous solution containing the metal element B source, the concentration of the metal element B source is 0.01-40 wt %.

7. The preparation method according to claim 3, characterized in that: The drying temperature is 5 to 150° C. The drying time is 1 to 100 hours; The calcination temperature is 150-1200°C; Preferably, the calcination temperature is 150-1000°C; Preferably, the calcination temperature is 200-1000°C; The calcination time is 0.5 to 50 hours; The calcination atmosphere is air atmosphere, oxygen-containing atmosphere, nitrogen atmosphere or inert gas atmosphere.

8. A method for preparing aviation kerosene by hydrogenation of CO / CO2, It is characterized in that The following steps are involved: The hydrogen and the raw material containing CO and / or CO2 are contacted with a catalyst to react and obtain aviation kerosene; Wherein, the catalyst is the catalyst according to any one of claims 1 or 2.

9. The method according to claim 8, characterized in that The reaction temperature is 150-450°C; The reaction pressure is 0.1-8Mpa; The volume ratio of the hydrogen to the raw material containing CO and / or CO2 is 0.2 to 8; The total GHSV of the hydrogen and the raw materials containing CO and / or CO2 is 200 to 20000 h -1 .

10. The method according to claim 8, characterized in that The catalyst is reduced; The reduction temperature is 200-650°C; The reduction time is 1 to 50 hours; The reducing atmosphere is a hydrogen atmosphere and / or a carbon monoxide atmosphere.

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