A zeolite molecular sieve composite catalyst, a preparation method thereof and application of the catalyst in catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation

Abstract

The application provides a zeolite molecular sieve composite catalyst, a preparation method thereof and application of the zeolite molecular sieve composite catalyst in catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation, and relates to the fields of biomass resource utilization and industrial catalysis technology.The zeolite molecular sieve composite catalyst comprises a lamellar MCM-22 molecular sieve carrier and metal nanoparticles loaded on the lamellar MCM-22 molecular sieve carrier, the metal nanoparticles comprise one or more of zinc, zirconium, manganese, indium and tin nanoparticles, and the mass of each metal nanoparticle is independently 0.05-5% of the mass of the lamellar MCM-22 molecular sieve carrier. The zeolite molecular sieve composite catalyst is used in catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation, so that the yield of liquid-phase product monocyclic aromatic hydrocarbons can be improved, and the composite catalyst still exhibits excellent catalytic performance after regeneration and multiple recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biomass resource utilization and industrial catalysis, in particular to a zeolite molecular sieve composite catalyst, a preparation method thereof and application of the catalyst in catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation. BACKGROUND

[0002] Biomass is directly or indirectly derived from solar energy and photosynthesis of plants, including plants, crops, forest products, marine products, agricultural and forestry wastes, municipal wastes and the like. Compared with traditional fossil energy, biomass has the characteristics of renewability and abundant reserves, and the global annual biomass production is about 200 billion tons. Converting biomass into fuels or organic chemicals and the like can not only develop a new way for high value-added utilization of biomass, but also alleviate the dependence on traditional non-renewable fossil resources.

[0003] Biomass is mainly composed of C, H and O elements, and the total content of the three elements can account for more than 95% of the total content. In addition, biomass also contains a small amount of non-metallic elements such as S and N and metallic elements. Compared with fossil fuels, the carbon content of biomass is very low, and the oxygen content is very high. In terms of composition, biomass mainly contains cellulose, hemicellulose and lignin. Cellulose has the highest content in biomass, which is composed of glucose units connected by β-1,4-glucoside bonds. Hemicellulose is composed of short-chain heteropolysaccharides, including six-carbon sugars (glucose, mannose and galactose) and five-carbon sugars (xylose and arabinose) as well as a small part of rhamnose and fructose, which presents amorphous and multi-branched chain structure. Lignin is composed of p-hydroxyphenylpropane, guaiacylpropane and syringylpropane units connected by different kinds of aryl linkages. China has abundant biomass resources, for example, Xinjiang is the largest cotton producing area in China, and the cotton stalk yield can reach 20 million tons per year. Through biomass pyrolysis and directional hydrogenation catalysis, liquid fuel oil products rich in aromatic hydrocarbons can be prepared with high selectivity, which can open up a new path for high value-added utilization of abundant resource-type agricultural straw waste, and also provides a green and renewable route for production of fuel oil products.

[0004] Zeolite molecular sieve materials have been the most potential catalysts for the directional preparation of aromatic-rich oil products from biomass pyrolysis and hydrogenation due to their excellent thermal stability, hydrothermal stability, simple and adjustable acidity, regular pore structure and rich topological structure. So far, zeolites such as ZSM-5, HY, Beta and Mordenite have been used in the reaction of directional preparation of fuel oil products from biomass pyrolysis and hydrogenation catalysis, and ZSM-5 has shown excellent aromatization, isomerization and unique shape-selective catalytic ability due to its suitable pore size and acidity, thereby having better aromatic yield. For example, the patent with the authorization announcement number CN103920526B reports a composite catalyst with HZSM-5 as the carrier, loading non-metallic element phosphorus and transition metal elements nickel, zinc and copper, which is used for preparing aromatic hydrocarbon compounds from the co-pyrolysis of pine wood and plastic. However, the microporous ZSM-5 catalyst has serious diffusion resistance in the hydrogenation catalytic reaction, the active centers in the pore are easy to be deactivated due to serious carbon deposition, and the yield of monocyclic aromatic hydrocarbons is low. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a zeolite molecular sieve composite catalyst, a preparation method thereof and an application thereof in the catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation. The zeolite molecular sieve composite catalyst provided by the present application can reduce the occurrence of carbon deposition reaction and has high yield of monocyclic aromatic hydrocarbons.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions.

[0007] The present application provides a zeolite molecular sieve composite catalyst, which comprises a lamellar MCM-22 molecular sieve carrier and metal nanoparticles loaded on the lamellar MCM-22 molecular sieve carrier, wherein the metal nanoparticles comprise one or more of zinc, zirconium, manganese, indium and tin nanoparticles, and the mass of each metal nanoparticle is independently 0.05-5% of the mass of the lamellar MCM-22 molecular sieve carrier.

[0008] Preferably, the particle size of the zeolite molecular sieve composite catalyst is 20-100 mesh.

[0009] The present application provides a preparation method of the above-mentioned zeolite molecular sieve composite catalyst, which comprises the following steps:

[0010] The lamellar MCM-22 molecular sieve carrier is immersed in an aqueous solution of a precursor salt of the metal nanoparticles, and the obtained immersion product is sequentially subjected to drying, calcination and hydrogen reduction to obtain the zeolite molecular sieve composite catalyst.

[0011] Preferably, the temperature of the immersion is 30-80℃.

[0012] Preferably, the temperature of the calcination is 500-600 DEG C, and the time is 2-6h.

[0013] Preferably, the temperature of the hydrogen reduction is 350-650 DEG C, and the time is 2-8h, the hydrogen reduction is carried out in a mixed atmosphere of hydrogen and a protective gas atmosphere, the volume fraction of hydrogen in the mixed atmosphere is 5-15%, and the flow rate of the mixed atmosphere is 100-500 mL / min.

[0014] Preferably, the preparation method of the lamellar MCM-22 molecular sieve carrier comprises the following steps:

[0015] A silicon source, an aluminum source, sodium hydroxide, hexamethylene imine and water are mixed to obtain a precursor gel; the silicon source, the aluminum source and the sodium hydroxide are respectively calculated as SiO2, Al2O3 and Na2O, and the molar ratio of the silicon source, the aluminum source, the sodium hydroxide, the hexamethylene imine and the water is 1:0.005-0.02:0.05-0.075:0.2-0.28:30;

[0016] The precursor gel is subjected to hydrothermal crystallization to obtain a lamellar MCM-22 molecular sieve raw powder;

[0017] The lamellar MCM-22 molecular sieve raw powder is sequentially subjected to first calcination, ammonium ion exchange and second calcination to obtain the lamellar MCM-22 molecular sieve carrier.

[0018] Preferably, the temperature of the hydrothermal crystallization is 140-170 DEG C, and the time is 3-12 days; the temperature of the first calcination is 500-600 DEG C, and the time is 3-8h; and the temperature of the second calcination is 400-600 DEG C, and the time is 3-8h.

[0019] The application provides application of the zeolite molecular sieve composite catalyst in a reaction of catalytic preparation of aromatic hydrocarbons from biomass pyrolysis and hydrogenation.

[0020] Preferably, the mass ratio of the zeolite molecular sieve composite catalyst to biomass is 1:1-5:1; the temperature of the reaction is 400-700 DEG C, and the time is 0.5-5h, and the reaction is carried out in a hydrogen atmosphere.

[0021] This invention provides a zeolite molecular sieve composite catalyst, comprising a layered MCM-22 molecular sieve support and metal nanoparticles loaded on the layered MCM-22 molecular sieve support. The metal nanoparticles include one or more of zinc, zirconium, manganese, indium, and tin nanoparticles, with each metal nanoparticle's mass independently ranging from 0.05% to 5% of the mass of the layered MCM-22 molecular sieve support. This invention uses a pseudo-two-dimensional layered MCM-22 molecular sieve as a support, which can significantly reduce mass transfer resistance and decrease the occurrence of carbon deposition reactions. This invention loads specific metal nanoparticles (one or more of zinc, zirconium, manganese, indium, and tin nanoparticles) as active ingredients within the pores of the MCM-22 molecular sieve and controls the amount of metal nanoparticles added, establishing a synergistic catalytic mechanism between the metal and the acidic sites of the MCM-22 molecular sieve, thereby improving the level of aromatization. Furthermore, the support and metal components of the zeolite molecular sieve composite catalyst are inexpensive.

[0022] This invention provides the application of the zeolite molecular sieve composite catalyst described above in the catalytic production of aromatics from biomass pyrolysis hydrogenation. Using the zeolite molecular sieve composite catalyst in the catalytic production of aromatics from biomass pyrolysis hydrogenation can improve the yield of aromatics in the liquid phase and the selectivity of monocyclic aromatics, achieving high selectivity in aromatic production. Furthermore, the composite catalyst still exhibits excellent catalytic performance after regeneration and multiple cycles.

[0023] The results of the examples show that the zeolite molecular sieve composite catalyst provided by the present invention, when used for the catalytic hydrogenation of biomass to produce aromatics, achieves a yield of 24% of monocyclic aromatic hydrocarbons in the optimal liquid phase product at a catalytic reaction temperature of 500°C, which is 44% higher than that of the unsupported metal MCM-22 molecular sieve catalyst. Attached Figure Description

[0024] Figure 1 The X-ray powder diffraction patterns of the layered MCM-22 molecular sieve raw powder and the zeolite molecular sieve composite catalyst 2%Zn-2%Zr@HMCM-22(25) in Example 1 are shown.

[0025] Figure 2 This is a high-magnification transmission electron microscope image of the hydrogen-type powder sheet-like MCM-22 molecular sieve support prepared in Example 1. Detailed Implementation

[0026] This invention provides a zeolite molecular sieve composite catalyst, comprising a layered MCM-22 molecular sieve support and metal nanoparticles loaded on the layered MCM-22 molecular sieve support. The metal nanoparticles include one or more of zinc, zirconium, manganese, indium, and tin nanoparticles, and the mass of each metal nanoparticle is independently 0.05 to 5% of the mass of the layered MCM-22 molecular sieve support.

[0027] In this invention, the metal nanoparticles preferably include one or more of zirconium, manganese, indium, and tin nanoparticles, as well as zinc nanoparticles, more preferably zinc and zirconium, or zinc and indium, or zinc and manganese, or zinc and tin, or zinc, zirconium, manganese, indium, and tin. In this invention, the mass of each metal nanoparticle is preferably 0.5% to 5% of the mass of the layered MCM-22 molecular sieve support, more preferably 1% to 2%.

[0028] In this invention, the particle size of the zeolite molecular sieve composite catalyst is preferably 20-100 mesh, more preferably 40-60 mesh.

[0029] This invention uses pseudo-two-dimensional layered MCM-22 as a carrier, which can significantly reduce mass transfer resistance and reduce the occurrence of carbon deposition reaction. Furthermore, based on screening a large number of metal active components and optimizing the amount of metal added, this invention has determined that the above-mentioned metal components are loaded in the pores of MCM-22 molecular sieve, and established a synergistic catalytic mechanism between metal and acidic sites of MCM-22 molecular sieve, thereby improving the level of aromatization.

[0030] This invention provides a method for preparing the zeolite molecular sieve composite catalyst described above, comprising the following steps:

[0031] The layered MCM-22 molecular sieve support was impregnated in the precursor salt solution of the metal nanoparticles, and the resulting impregnation product was successively dried, calcined and reduced with hydrogen to obtain the metal-loaded zeolite molecular sieve composite catalyst.

[0032] First, the layered MCM-22 molecular sieve carrier will be described.

[0033] This invention does not impose any particular requirements on the layered MCM-22 molecular sieve support; it can be prepared using commercially available products or methods well-known to those skilled in the art. In embodiments of this invention, the preferred method for preparing the layered MCM-22 molecular sieve support includes the following steps:

[0034] A precursor gel is obtained by mixing a silicon source, an aluminum source, sodium hydroxide, hexamethyleneimine, and water; the silicon source, aluminum source, and sodium hydroxide are calculated as SiO2, Al2O3, and Na2O, respectively, and the molar ratio of the silicon source, aluminum source, sodium hydroxide, hexamethyleneimine, and water is 1:0.005~0.02:0.05~0.075:0.2~0.28:30.

[0035] The precursor gel was subjected to hydrothermal crystallization to obtain layered MCM-22 molecular sieve raw powder.

[0036] The layered MCM-22 molecular sieve raw powder was subjected to a first calcination, an ammonium ion exchange, and a second calcination in sequence to obtain the layered MCM-22 molecular sieve carrier.

[0037] This invention mixes a silicon source, an aluminum source, sodium hydroxide, hexamethyleneimine, and water to obtain a precursor gel. In this invention, the silicon source is preferably one or more of silica sol, fumed silica, and tetraethyl orthosilicate; the aluminum source is preferably one or more of sodium aluminate, aluminum isopropoxide, and boehmite. In this invention, the hexamethyleneimine serves as a template agent, and the water is preferably deionized water. In this invention, the silicon source, aluminum source, and sodium hydroxide are calculated as SiO2, Al2O3, and Na2O, respectively, and the molar ratio of the silicon source, aluminum source, sodium hydroxide, hexamethyleneimine, and water is preferably 1:0.005–0.02:0.05–0.075:0.2–0.28:30, more preferably 1:0.01–0.02:0.06–0.075:0.28:30. This invention optimizes the acidity of the support by adjusting the silicon-to-aluminum ratio, which is more conducive to the synergistic catalytic effect of metal elements and acidic sites of molecular sieve support.

[0038] In this invention, the preferred method for mixing the silicon source, aluminum source, sodium hydroxide, hexamethyleneimine, and water is as follows:

[0039] Add aluminum source to water and stir for 5 minutes to obtain the first mixture;

[0040] Sodium hydroxide was added to the first mixture and stirred for 10 minutes to obtain the second mixture;

[0041] Add hexamethyleneimine dropwise to the second mixture and stir for 15 minutes to obtain the third mixture;

[0042] A silicon source was added to the third mixture, stirred for 1 hour, and then sonicated for 20 minutes to obtain the precursor gel.

[0043] After obtaining the precursor gel, the present invention performs hydrothermal crystallization on the precursor gel to obtain layered MCM-22 molecular sieve raw powder. In the present invention, the hydrothermal crystallization temperature is preferably 140-170℃, more preferably 150℃, and the time is preferably 3-12 days, more preferably 3-7 days. Preferably, the precursor gel is sealed in a crystallization vessel and then placed in a homogeneous reactor for hydrothermal crystallization; the rotation speed of the homogeneous reactor is preferably 15-50 r / min.

[0044] After the hydrothermal crystallization is completed, the present invention preferably cools, washes and dries the obtained crystallization product in sequence to obtain the lamellar MCM-22 molecular sieve raw powder.

[0045] After obtaining the layered MCM-22 molecular sieve raw powder, the present invention sequentially subjectes the layered MCM-22 molecular sieve raw powder to a first calcination, ammonium ion exchange, and a second calcination to obtain the layered MCM-22 molecular sieve support. In the present invention, the temperature of the first calcination is preferably 500-600℃, more preferably 550℃, the time is preferably 3-8h, more preferably 6h, and the heating rate to the first calcination temperature is preferably 1-5℃ / min. The pores of the layered MCM-22 molecular sieve raw powder contain template agent molecules (hexamethyleneimine). The present invention removes the template agent molecules through the first calcination to obtain sodium-type MCM-22 molecular sieve.

[0046] In this invention, the ammonium ion exchange is preferably carried out in an ammonium nitrate solution, and the specific operation of the ammonium ion exchange is preferably as follows:

[0047] The sodium-type MCM-22 molecular sieve was placed in an ammonium nitrate solution for ammonium ion exchange, followed by centrifugation. The ammonium ion exchange-centrifugation operation was then repeated. Finally, the resulting molecular sieve was centrifuged, washed until neutral, and dried.

[0048] In this invention, the concentration of the ammonium nitrate solution is preferably 1 mol / L, and the mass ratio of the sodium-type MCM-22 molecular sieve to the ammonium nitrate solution is preferably 1:15. In this invention, the repetition is preferably performed twice, the temperature for each ammonium ion exchange is preferably 80°C, and the time is preferably 2 hours. This invention converts the sodium-type MCM-22 molecular sieve into the ammonium-type MCM-22 molecular sieve through ammonium ion exchange.

[0049] In this invention, the temperature of the second calcination is preferably 400–600°C, more preferably 550°C, the time is preferably 3–8 hours, more preferably 6 hours, and the heating rate to the second calcination temperature is preferably 1–10°C / min. In this invention, both the first and second calcinations are preferably carried out in a muffle furnace. This invention converts ammonium-type MCM-22 molecular sieves into hydrogen-type MCM-22 molecular sieves through the second calcination. The hydrogen-type MCM-22 molecular sieves contain Brønsted acid sites and possess catalytic activity.

[0050] The preparation of the zeolite molecular sieve composite catalyst is described below.

[0051] In this invention, the precursor salt solution of the metal nanoparticles is preferably an aqueous solution of the nitrate, sulfate, or chloride salt of the metal nanoparticles. Specifically, the precursor salt solution of the metal nanoparticles is prepared by dissolving the precursor salt of the metal nanoparticles in deionized water. In this invention, the impregnation is preferably performed using an equal-volume impregnation method. This invention does not have special requirements for the operation of the equal-volume impregnation method; any operation well-known to those skilled in the art can be used. In this invention, the impregnation temperature is preferably 30–80°C, more preferably 50°C. The impregnation is preferably carried out under stirring conditions to promote the entry of metal ions into the molecular sieve channels; during the stirring process, water slowly evaporates to form a paste-like consistency.

[0052] In this invention, the drying temperature is preferably 80°C. After drying, the resulting material is preferably ground into powder.

[0053] In this invention, the calcination temperature is preferably 500–600°C, more preferably 550°C, and the calcination time is preferably 2–6 hours; the calcination is preferably carried out in an air atmosphere. During the calcination process, the metal salt anchored in the molecular sieve channels forms corresponding metal oxides or composite metal oxides under conditions of high temperature and oxygen participation.

[0054] In this invention, the hydrogen reduction temperature is preferably 350–650°C, more preferably 450–550°C, and the time is preferably 2–8 hours, more preferably 4–6 hours. The hydrogen reduction is preferably carried out in a mixed atmosphere of hydrogen and a protective gas, preferably argon. The volume fraction of hydrogen in the mixed atmosphere is preferably 5–15%, and the flow rate of the mixed atmosphere is preferably 100–500 mL / min, more preferably 200–300 mL / min. In this invention, the hydrogen reduction is preferably carried out in a tube furnace. During the hydrogen reduction process, the metal oxide is reduced to metal nanoparticles or composite metal nanoparticles.

[0055] After the hydrogen reduction is completed, the obtained metal-loaded zeolite molecular sieve composite catalyst is preferably pressed into tablets and crushed in sequence, and then sieved into 20-100 mesh, preferably 40-60 mesh.

[0056] This invention uses common silicon sources such as silica sol, aluminum sources such as hexamethyleneimine and sodium aluminate, and metal salts such as water-soluble zinc salts as raw materials to prepare the metal-loaded zeolite molecular sieve composite catalyst. The raw materials are widely available, inexpensive, and have low production costs.

[0057] This invention provides the application of the zeolite molecular sieve composite catalyst described in the above technical solutions or the zeolite molecular sieve composite catalyst prepared by the above technical solutions in the catalytic hydrogenation reaction of biomass to produce aromatics.

[0058] This invention does not have any special requirements for the biomass used; any biomass well-known to those skilled in the art can be used, such as crop straw from cotton, rice, corn, wheat, etc., and leaf biomass (such as poplar leaves). Before the reaction, this invention preferably cleans, dries, and crushes the biomass to obtain powdered biomass.

[0059] In this invention, the mass ratio of the zeolite molecular sieve composite catalyst to biomass is preferably 1:1 to 5:1, more preferably 2:1. In this invention, the reaction temperature is preferably 400 to 700°C, more preferably 500 to 600°C, the reaction time is preferably 0.5 to 5 hours, more preferably 0.5 to 2 hours, and the heating rate to the reaction temperature is preferably 20°C / min; the reaction is preferably carried out in a hydrogen atmosphere.

[0060] The zeolite molecular sieve composite catalyst provided by this invention, when used in the catalytic hydrogenation of biomass to produce aromatics, can improve the yield of aromatics in the liquid phase and the selectivity of monocyclic aromatics (high yield of monocyclic aromatics). Furthermore, the composite catalyst still exhibits excellent catalytic performance after regeneration and multiple cycles. This invention solves the problems in the prior art of catalytic hydrogenation of biomass to produce aromatics, such as significant steric hindrance leading to severe catalyst carbon buildup and low yield of monocyclic aromatics.

[0061] To further illustrate the present invention, the following detailed description, in conjunction with examples, of the zeolite molecular sieve composite catalyst provided by the present invention, its preparation method, and its application in the catalytic production of aromatics from biomass pyrolysis hydrogenation, should not be construed as limiting the scope of protection of the present invention.

[0062] Example 1

[0063] The preparation method of the zeolite molecular sieve composite catalyst is as follows:

[0064] (1) Add 90g of deionized water to a round-bottom flask, then add 0.746g of sodium aluminate and stir at room temperature for 5min; next, weigh 0.806g of sodium hydroxide and add it to the above mixture and stir for 10min; then weigh 5.602g of hexamethyleneimine and add it dropwise to the above mixture and stir for 15min; then, add 30g of silica sol (mass fraction 40%) dropwise and stir for 1h, then sonicate for 20min; then, place it in a homogeneous reactor and hydrothermally crystallize at 150℃ for 72h at a speed of 26.5r / min; finally, cool, centrifuge and wash until the supernatant is neutral, dry, and obtain the layered MCM-22 molecular sieve raw powder.

[0065] (2) The layered MCM-22 molecular sieve raw powder obtained in (1) was calcined in a muffle furnace at 550℃ for 6h, with a heating rate of 1℃ / min; the obtained sodium-type MCM-22 molecular sieve was then placed in a 1mol / L ammonium nitrate solution with a solid-liquid mass ratio of 1:15 and treated at 80℃ for 2h. After centrifugation, the above steps were repeated twice. Then, the mixture was centrifuged and washed until neutral, dried, and then calcined in a muffle furnace at 550℃ for 6h to obtain the hydrogen-type powdered layered MCM-22 molecular sieve carrier.

[0066] (3) Take 0.1831g of zinc nitrate hexahydrate and 0.1882g of zirconium nitrate pentahydrate and put them into 20g of deionized water. Stir until a solution is formed. Weigh 2g of hydrogen-type powder MCM-22 molecular sieve carrier and add it to the above metal ion solution. Stir at 50°C until it becomes a paste. Dry at 80°C and grind it into powder.

[0067] (4) The powder obtained in (3) was calcined at 550°C in air for 6 hours, and then reduced in a hydrogen-protective atmosphere at 450°C for 4 hours. The hydrogen component in the hydrogen-protective atmosphere was 15%, and the mixed gas flow rate was 300 mL / min. The reduced zinc-zirconium supported catalyst was pressed, crushed, and sieved to 40-60 mesh to obtain the zeolite molecular sieve composite catalyst 2%Zn-2%Zr@HMCM-22(25).

[0068] Figure 1 The X-ray powder diffraction patterns are those of the layered MCM-22 molecular sieve raw powder (i.e., MCM-22 before calcination) and the zeolite molecular sieve composite catalyst 2%Zn-2%Zr@HMCM-22(25) in Example 1. Figure 1 It can be seen that the diffraction peaks of the original layered MCM-22 molecular sieve powder before calcination are consistent with the characteristic diffraction peaks in the literature; the characteristic diffraction peaks of 2%Zn-2%Zr@HMCM-22(25) are consistent with the characteristic diffraction peaks of MCM-22, and no characteristic diffraction peaks of zinc oxide and zirconium oxide appear.

[0069] Figure 2 This is a high-magnification transmission electron microscope (TEM) image of the hydrogen-form powdered layered MCM-22 molecular sieve support prepared in Example 1. Figure 2 It can be seen that the prepared MCM-22 molecular sieve support is in the form of sheets with a layer thickness of less than 10 nm.

[0070] Example 2

[0071] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0072] In step (3), 0.1831g of zinc nitrate hexahydrate is placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-type powder MCM-22 molecular sieve carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste, dried at 80°C, and then ground into powder.

[0073] The rest is the same as in Example 1.

[0074] A zeolite molecular sieve composite catalyst of 2% Zn@HMCM-22 (25) was prepared.

[0075] Example 3

[0076] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0077] In step (3), 0.1882g of zirconium nitrate pentahydrate was placed in 20g of deionized water and stirred until a solution was formed. 2g of hydrogen-type powder MCM-22 molecular sieve carrier was weighed and added to the above metal ion solution. The mixture was stirred at 50°C until it became a paste, dried at 80°C, and then ground into powder.

[0078] The rest is the same as in Example 1.

[0079] A zeolite molecular sieve composite catalyst of 2% Zr@HMCM-22(25) was prepared.

[0080] Example 4

[0081] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0082] In step (3), 0.0915g of zinc nitrate hexahydrate and 0.0941g of zirconium nitrate pentahydrate are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-type powder MCM-22 molecular sieve carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste, dried at 80°C, and then ground into powder.

[0083] The rest is the same as in Example 1.

[0084] A zeolite molecular sieve composite catalyst of 1%Zn-1%Zr@HMCM-22(25) was prepared.

[0085] Example 5

[0086] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0087] In steps (1) to (2), 90g of deionized water was added to a round-bottom flask, and 0.3744g of sodium aluminate was added. The mixture was stirred at room temperature for 5 minutes. Next, 1.02g of sodium hydroxide was weighed and added to the above mixture. The mixture was stirred for 10 minutes. The remaining steps were the same, and a hydrogen-type powder sheet-like MCM-22 molecular sieve carrier with a silicon-to-aluminum ratio of 50 was obtained.

[0088] In step (3), 0.1831g of zinc nitrate hexahydrate and 0.1882g of zirconium nitrate pentahydrate are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-form powder MCM-22 carrier with a silicon-to-aluminum ratio of 50 is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste, dried at 80°C, and then ground into powder.

[0089] The rest is the same as in Example 1.

[0090] A zeolite molecular sieve composite catalyst of 2%Zn-2%Zr@HMCM-22(50) was prepared.

[0091] Example 6

[0092] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0093] In step (3), 0.0915g of zinc nitrate hexahydrate and 0.0524g of indium nitrate are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-type powder MCM-22 carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste. After drying at 80°C, it is ground into powder.

[0094] The rest is the same as in Example 1.

[0095] A zeolite molecular sieve composite catalyst of 1%Zn-1%In@HMCM-22(25) was prepared.

[0096] Example 7

[0097] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0098] In step (3), 0.0915g of zinc nitrate hexahydrate and 0.1044g of manganese nitrate hexahydrate are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-type powder MCM-22 carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste. After drying at 80°C, it is ground into powder.

[0099] The rest is the same as in Example 1.

[0100] A zeolite molecular sieve composite catalyst of 1%Zn-1%Mn@HMCM-22(25) was prepared.

[0101] Example 8

[0102] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0103] In step (3), 0.0915g of zinc nitrate hexahydrate and 0.0438g of tin tetrachloride are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-type powder MCM-22 carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste. After drying at 80°C, it is ground into powder.

[0104] The rest is the same as in Example 1.

[0105] A zeolite molecular sieve composite catalyst of 1%Zn-1%Sn@HMCM-22(25) was prepared.

[0106] Example 9

[0107] The zeolite molecular sieve composite catalyst was prepared according to the method of Example 1, but the difference from Example 1 is as follows:

[0108] In step (3), 0.0915g of zinc nitrate hexahydrate, 0.0941g of zirconium nitrate pentahydrate, 0.0524g of indium nitrate, 0.1044g of manganese nitrate hexahydrate and 0.0438g of tin tetrachloride are placed in 20g of deionized water and stirred until a solution is formed. 2g of hydrogen-form powder MCM-22 carrier is weighed and added to the above metal ion solution. The mixture is stirred at 50°C until it becomes a paste, dried at 80°C and then ground into powder.

[0109] The rest is the same as in Example 1.

[0110] A zeolite molecular sieve composite catalyst of 1%Zn-1%Zr-1%In-1%Mn-1%Sn@HMCM-22(25) was prepared.

[0111] Comparative Example 1

[0112] The catalyst was prepared according to the method of Example 1, the difference being that:

[0113] Steps (3) and (4) are omitted. The control catalyst is prepared directly by pressing the hydrogen-type powder MCM-22 with a silicon-to-aluminum ratio of 25 under the same compression molding conditions. The sample is labeled as: HMCM-22(25).

[0114] Comparative Example 2

[0115] The catalyst was prepared according to the method of Example 5, the difference being that:

[0116] Steps (3) and (4) are omitted. The control catalyst is prepared directly by pressing the hydrogen-form powder HMCM-22 with a silicon-to-aluminum ratio of 50 under the same compression molding conditions. The sample is labeled as: HMCM-22(50).

[0117] Application Example 1

[0118] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was conducted in a fixed-bed quartz tube reactor under atmospheric pressure with two-stage heating. Typical Xinjiang cotton stalks were used as raw material, which were cleaned, dried, and crushed to obtain powdered cotton stalks. First, 0.6 g of the 2% Zn-2% Zr@HMCM-22 catalyst prepared in Example 1 was placed in the lower part of the quartz tube; then quartz wool was placed in the middle, and 0.3 g of cotton stalks were weighed and placed in the upper suspended tray. Under a hydrogen atmosphere, the temperature of the reaction tube was raised to 500°C at a heating rate of 20°C / min and maintained for 30 min, while the liquid and gaseous products were collected simultaneously.

[0119] For the 2%Zn-2%Zr@HMCM-22(25) catalyst, the yield of cotton stalk-based coke was calculated to be 26%, the yield of tar was 51%, and the yield of gas phase products was 23%. The selectivity for liquid phase products, monocyclic aromatic hydrocarbons, was 39%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0120] Application Example 2

[0121] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference from Application Example 1 is that 0.6g of 2% Zn@HMCM-22(25) catalyst prepared in Example 2 was added. The yield of cotton stalk-based coke was calculated to be 26%, the tar yield was 50%, and the gas phase product yield was 24%. The selectivity for the liquid phase product monocyclic aromatics was 32%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0122] Application Example 3

[0123] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference from Application Example 1 is that 0.6g of 2% Zr@HMCM-22(25) catalyst prepared in Example 3 was added. The yield of cotton stalk-based coke was calculated to be 28%, the tar yield was 49%, and the gas phase product yield was 23%. The selectivity for the liquid phase product monocyclic aromatics was 29%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0124] Application Example 4

[0125] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference from Application Example 1 is that 0.6g of 1%Zn-1%Zr@HMCM-22(25) catalyst prepared in Example 4 was added. The yield of cotton stalk-based coke was calculated to be 28%, the tar yield was 49%, and the gas phase product yield was 23%. The selectivity for monocyclic aromatic hydrocarbons in the liquid phase product was 49%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0126] Application Example 5

[0127] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference between Application Example 1 and Application Example 1 is that 0.6g of 2%Zn-2%Zr@HMCM-22(50) catalyst prepared in Example 5 was added. The yield of cotton stalk-based coke was calculated to be 26%, the tar yield was 47%, and the gas phase product yield was 27%. The selectivity for monocyclic aromatic hydrocarbons in the liquid phase product was 36%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0128] Application Example 6

[0129] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference from Application Example 1 is that 0.6g of 1%Zn-1%In@HMCM-22(25) catalyst prepared in Example 6 was added. The yield of cotton stalk-based coke was calculated to be 28%, the tar yield was 47%, and the gas phase product yield was 25%. The selectivity for the liquid phase product monocyclic aromatics was 48%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0130] Application Example 7

[0131] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference between Application Example 1 and Application Example 1 is that 0.6g of 1%Zn-1%Mn@HMCM-22(25) catalyst prepared in Example 7 was added. The yield of cotton stalk-based coke was calculated to be 28%, the tar yield was 47%, and the gas phase product yield was 25%. The selectivity for the liquid phase product monocyclic aromatics was 46%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0132] Application Example 8

[0133] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference between Application Example 1 and Application Example 1 is that 0.6g of 1%Zn-1%Sn@HMCM-22(25) catalyst prepared in Example 8 was added. The yield of cotton stalk-based coke was calculated to be 28%, the tar yield was 49%, and the gas phase product yield was 23%. The selectivity for the liquid phase product monocyclic aromatics was 47%, of which monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0134] Application Example 9

[0135] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference from Application Example 1 is that 0.6g of 1%Zn-1%Zr-1%In-1%Mn-1%Sn@HMCM-22(25) catalyst prepared in Example 9 was added. The yield of cotton stalk-based coke was calculated to be 28%, the yield of tar was 48%, and the yield of gas phase products was 24%. The selectivity for monocyclic aromatic hydrocarbons in the liquid phase products was 46%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0136] Application Example 10

[0137] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 4. The difference between Application Example 4 and Application Example 4 is that corn cobs were used instead of cotton stalks as raw materials, and 0.6g of 1%Zn-1%Zr@HMCM-22(25) catalyst prepared in Example 4 was added. The yield of corn cob-based coke was calculated to be 30%, the yield of tar was 42%, and the yield of gas phase products was 28%. The selectivity for monocyclic aromatic hydrocarbons in liquid phase products was 41%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0138] Application Example 11

[0139] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 4. The difference between Application Example 4 and Application Example 4 is that wheat straw was used instead of cotton straw as raw material, and 0.6g of 1%Zn-1%Zr@HMCM-22(25) catalyst prepared in Example 4 was added. The yield of wheat straw-based coke was calculated to be 24%, the yield of tar was 43%, and the yield of gas phase products was 33%. The selectivity for monocyclic aromatic hydrocarbons in liquid phase products was 45%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0140] Application Example 12

[0141] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 4. The difference between Application Example 4 and Application Example 4 is that rice straw was used instead of cotton straw as raw material, and 0.6g of 1%Zn-1%Zr@HMCM-22(25) catalyst prepared in Example 4 was added. The calculated yield of rice straw-based coke was 25%, the yield of tar was 44%, and the yield of gas phase products was 31%. The selectivity for monocyclic aromatic hydrocarbons in liquid phase products was 40%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0142] Application Example 13

[0143] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 4. The difference between Application Example 4 and Application Example 4 is that poplar leaves were used instead of cotton stalks as raw materials, and 0.6g of 1%Zn-1%Zr@HMCM-22(25) catalyst prepared in Example 4 was added. The calculated yield of poplar leaf-based coke was 28%, the yield of tar was 36%, and the yield of gas phase products was 36%. The selectivity for monocyclic aromatic hydrocarbons in liquid phase products was 39%, of which monocyclic aromatic hydrocarbons were mainly benzene, toluene, xylene and ethylbenzene.

[0144] Application Example 14

[0145] The catalyst after the reaction in Example 4 was calcined at 800°C in air to remove carbon deposits, with a heating rate of 1°C / min and held at 800°C for 6 hours to obtain regenerated 1%Zn-1%Zr@HMCM-22(25). An in-situ catalytic pyrolysis experiment to produce aromatics from biomass tar was conducted according to the method in Example 4. The difference from Example 4 was that 0.6g of the regenerated 1%Zn-1%Zr@HMCM-22(25) catalyst from Example 4 was added. The calculated yields of cotton stalk-based coke after the first catalyst regeneration were 28%, tar yield was 49%, and gas phase product yield was 23%. The selectivity for the liquid phase product monocyclic aromatics was 45%, with the main monocyclic aromatics being benzene, toluene, xylene, and ethylbenzene.

[0146] Repeat the above catalyst regeneration steps and conduct an in-situ hydrogenation catalytic pyrolysis experiment of biomass tar to produce aromatics according to the method of Application Example 4. The calculated yield of cotton stalk-based coke after the second catalyst regeneration was 28%, the tar yield was 49%, and the gas phase product yield was 23%. The selectivity for the liquid phase product monocyclic aromatics was 44%, of which the monocyclic aromatics were mainly benzene, toluene, xylene, and ethylbenzene.

[0147] The above catalyst regeneration steps were repeated, and an in-situ hydrogenation catalytic pyrolysis experiment to produce aromatics from biomass tar was conducted according to the method in Application Example 4. The calculated yield of cotton stalk-based coke after the third catalyst regeneration was 28%, the tar yield was 49%, and the gas phase product yield was 23%. The selectivity for the liquid phase product monocyclic aromatics was 44%, of which the monocyclic aromatics were mainly benzene, toluene, xylene, and ethylbenzene.

[0148] The above catalyst regeneration steps were repeated, and an in-situ hydrogenation catalytic pyrolysis experiment to produce aromatics from biomass tar was conducted according to the method of Application Example 4. The yield of cotton stalk-based coke after the fourth catalyst regeneration was calculated to be 28%, the tar yield to be 49%, and the gas phase product yield to be 23%. The selectivity for the liquid phase product monocyclic aromatics was 43%, of which the monocyclic aromatics were mainly benzene, toluene, xylene, and ethylbenzene.

[0149] The above catalyst regeneration steps were repeated, and an in-situ hydrogenation catalytic pyrolysis experiment to produce aromatics from biomass tar was conducted according to the method in Application Example 4. The yield of cotton stalk-based coke after the fifth catalyst regeneration was calculated to be 28%, the tar yield to be 49%, and the gas phase product yield to be 23%. The selectivity for the liquid phase product monocyclic aromatics was 43%, of which the monocyclic aromatics were mainly benzene, toluene, xylene, and ethylbenzene.

[0150] Comparative Application Example 1

[0151] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference between Application Example 1 and Application Example 1 is that 0.6g of HMCM-22(25) catalyst prepared in Comparative Example 1 was added. The yield of cotton stalk-based coke was calculated to be 27%, the tar yield was 52%, and the gas phase product yield was 21%. The selectivity for the liquid phase product monocyclic aromatics was 32%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0152] Comparative Application Example 2

[0153] The in-situ hydrogenation catalytic pyrolysis of biomass tar to produce aromatics was carried out according to the method of Application Example 1. The difference between Application Example 1 and Application Example 1 is that 0.6g of HMCM-22(50) catalyst prepared in Comparative Example 2 was added. The calculated yield of cotton stalk-based coke was 26%, the tar yield was 50%, and the gas phase product yield was 24%. The selectivity for the liquid phase product monocyclic aromatics was 28%, of which the monocyclic aromatics were mainly benzene, toluene, xylene and ethylbenzene.

[0154] Table 1 shows the results of coke, tar, gaseous products, and monocyclic aromatics from the biomass pyrolysis catalytic production experiments of Application Examples 1-14 and Comparative Application Examples 1-2:

[0155] Table 1. Experimental results of biomass pyrolysis catalytic production of aromatics in Application Examples 1-13 and Comparative Application Examples 1-2.

[0156]

[0157]

[0158] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a zeolite molecular sieve composite catalyst in the catalytic hydrogenation reaction of biomass pyrolysis to produce aromatics, wherein the zeolite molecular sieve composite catalyst comprises a layered MCM-22 molecular sieve support and metal nanoparticles supported on the layered MCM-22 molecular sieve support, wherein the metal nanoparticles comprise one or more of zinc, zirconium, manganese, indium, and tin nanoparticles, and the mass of each metal nanoparticle is independently 0.05~5% of the mass of the layered MCM-22 molecular sieve support.

2. The application according to claim 1, characterized in that, The particle size of the zeolite molecular sieve composite catalyst is 20~100 mesh.

3. The application according to claim 1 or 2, characterized in that, The preparation method of the zeolite molecular sieve composite catalyst includes the following steps: The layered MCM-22 molecular sieve support was impregnated in the precursor salt solution of the metal nanoparticles, and the resulting impregnation product was successively dried, calcined and reduced with hydrogen to obtain the zeolite molecular sieve composite catalyst.

4. The application according to claim 3, characterized in that, The impregnation temperature is 30~80℃.

5. The application according to claim 3, characterized in that, The roasting temperature is 500~600℃ and the time is 2~6h.

6. The application according to claim 3, characterized in that, The hydrogen reduction is carried out at a temperature of 350~650℃ for 2~8h, in a mixed atmosphere of hydrogen and protective gas, wherein the volume fraction of hydrogen in the mixed atmosphere is 5~15%, and the flow rate of the mixed atmosphere is 100~500mL / min.

7. The application according to claim 3, characterized in that, The preparation method of the layered MCM-22 molecular sieve support includes the following steps: A precursor gel is obtained by mixing a silicon source, an aluminum source, sodium hydroxide, hexamethyleneimine, and water; the silicon source, aluminum source, and sodium hydroxide are calculated as SiO2, Al2O3, and Na2O, respectively, and the molar ratio of the silicon source, aluminum source, sodium hydroxide, hexamethyleneimine, and water is 1:0.005~0.02:0.05~0.075:0.2~0.28:

30. The precursor gel was subjected to hydrothermal crystallization to obtain layered MCM-22 molecular sieve raw powder. The layered MCM-22 molecular sieve raw powder was subjected to a first calcination, an ammonium ion exchange, and a second calcination in sequence to obtain the layered MCM-22 molecular sieve carrier.

8. The application according to claim 7, characterized in that, The hydrothermal crystallization temperature is 140~170℃ and the time is 3~12 days; the first calcination temperature is 500~600℃ and the time is 3~8 hours; the second calcination temperature is 400~600℃ and the time is 3~8 hours.

9. The application according to claim 1, characterized in that, The mass ratio of the zeolite molecular sieve composite catalyst to biomass is 1:1 to 5:1; the reaction temperature is 400 to 700°C, the time is 0.5 to 5 hours, and the reaction is carried out in a hydrogen atmosphere.

Images