Catalyst and preparation method thereof, preparation method of aromatic compound and application thereof

Abstract

The present invention belongs to the technical field of comprehensive utilization of solid waste, and specifically relates to a catalyst and a preparation method thereof, a preparation method of aromatic compounds and applications. The preparation method of the catalyst comprises the following steps: calcining a molecular sieve for the first time, then dispersing it into an aqueous solution of gallium nitrate, ultrasonically dispersing it at room temperature, drying it, and calcining it for the second time to obtain a catalyst; the molecular sieve is one of ZSM-5 zeolite, Y-zeolite, and β-zeolite. The catalyst prepared by the present invention has the advantages of high catalytic activity, good stability, high selectivity, and easy recovery. It can efficiently catalyze and pyrolyze waste epoxy resin to generate liquid oil rich in aromatic compounds, and realizes the clean disposal and resource utilization of waste epoxy resin including waste epoxy resin fan blades, waste epoxy resin circuit boards, and waste epoxy resin building materials.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of solid wastes, and specifically relates to a catalyst and a preparation method thereof, and a preparation method and application of aromatic compounds. Background Art

[0002] The disposal of waste epoxy resin materials has become an emerging issue. In recent years, epoxy resin composite materials have been widely used in aerospace, automobile, shipbuilding, building materials and other fields due to their outstanding advantages such as good strength and excellent corrosion resistance, fatigue resistance and electromagnetic shielding. In addition, with the increasing scale of wind power stations, the demand for wind turbine blades mainly made of epoxy resin composite materials has also increased year by year. However, the design life of wind power stations generally does not exceed 20 years, and a large number of wind turbine blade waste will be generated after the wind turbines are scrapped. Due to the high carbon emissions, energy consumption and costs of producing epoxy resin materials, it is necessary to recycle the epoxy resin in these waste wind turbine blades. In addition to wind turbine blades, epoxy resin-based circuit boards, building materials, etc. are also facing the problem of waste disposal. Due to the complex chemical properties of epoxy resin materials and the fact that they are thermosetting materials, they are insoluble in any organic solvents and cannot be melted when heated. It is very difficult to recycle them. At present, they are mostly treated by direct landfill or incineration, resulting in serious waste of resources. In addition, the incineration of epoxy resin will also produce a large amount of pollutants such as dioxins, which have a serious impact on the ecological environment. In contrast, pyrolysis technology can avoid the production of dioxins by cracking epoxy resin in an oxygen-free environment, and can also recover valuable coke, pyrolysis oil and gas products, which has broad application prospects. However, the main components of liquid oil in the direct pyrolysis products of epoxy resin are various phenolic products, mainly phenol, which have too high oxygen content and are highly corrosive, and have low utilization value and calorific value. Therefore, it is necessary to improve the quality of epoxy resin pyrolysis oil by catalysis and other means to realize the resource utilization of waste epoxy resin materials. Summary of the invention

[0003] The present invention aims to provide a catalyst and a preparation method thereof, a preparation method of aromatic compounds and their application. The present invention prepares a metal-supported molecular sieve catalyst with high catalytic activity, good stability and easy recovery, which can efficiently catalyze and pyrolyze waste epoxy resin to generate liquid oil rich in aromatic compounds.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: a method for preparing a catalyst, comprising the following steps:

[0005] The molecular sieve is calcined for the first time, then dispersed in a gallium nitrate aqueous solution, ultrasonically dispersed at room temperature, dried, and calcined for the second time to obtain a catalyst;

[0006] The molecular sieve is one of ZSM-5 zeolite, Y-zeolite and β-zeolite.

[0007] Preferably, the mass of gallium element in the gallium nitrate aqueous solution is 0.1% to 10% of the mass of the molecular sieve.

[0008] Preferably, the method for preparing the catalyst comprises at least one of the following (1) to (3):

[0009] (1) The first calcination conditions are: calcination in an air atmosphere at a temperature of 450 to 550° C. for 1 to 12 hours;

[0010] (2) The second calcination is carried out in an air atmosphere at a temperature of 500 to 550° C. for 1 to 12 hours;

[0011] (3) The ultrasonic dispersion time is 2 to 12 hours.

[0012] A catalyst prepared by the catalyst preparation method.

[0013] A method for preparing an aromatic compound comprises the following steps:

[0014] The raw materials and the catalyst are mixed and co-pyrolyzed in an oxygen-free environment to prepare aromatic compounds.

[0015] Preferably, the reaction conditions of the co-pyrolysis are: co-pyrolysis at 500-800°C, with a heating rate of 10-10 4 ℃ / s, and the holding time of co-pyrolysis is 5 to 60s.

[0016] Preferably, the method for preparing the aromatic compound comprises at least one of the following (1) to (4):

[0017] (1) The mass ratio of the raw material to the catalyst is 1:(1-10);

[0018] (2) The raw material is waste epoxy resin;

[0019] (3) The particle size of the raw material is 50 to 200 mesh;

[0020] (4) The oxygen-free environment is an environment in a nitrogen, argon or helium atmosphere.

[0021] More preferably, the waste epoxy resin includes at least one of waste epoxy resin fan blades, waste epoxy resin circuit boards, and waste epoxy resin building materials.

[0022] Preferably, the aromatic compounds include monocyclic aromatic hydrocarbons (benzene, toluene, xylene, etc.) and polycyclic aromatic hydrocarbons (naphthalene, methylnaphthalene, etc.).

[0023] Preferably, the catalyst is recovered by calcination after the co-pyrolysis reaction.

[0024] The recovery method comprises the following steps: calcining the catalyst in an air atmosphere, the calcination temperature is 500-550° C., and the heat preservation time is 1-12 hours to obtain a regenerated catalyst.

[0025] The invention discloses an application of the catalyst in the recovery of waste epoxy resin and thermal treatment of oxygen-containing thermosetting resin / plastic.

[0026] The present invention uses a specific type of molecular sieve for gallium loading to obtain a catalyst with excellent catalytic performance and good selectivity for monocyclic aromatic hydrocarbons. The metal gallium element in the catalyst can significantly improve the Lewis acid site while maintaining the strong acidity of the molecular sieve catalyst Bronsted acid site in the reaction system, thereby achieving efficient cracking and deoxygenation of the raw material (epoxy resin), and greatly reducing the oxygen content in the pyrolysis oil. At the same time, the gallium metal in the catalyst can adjust the pore structure of the catalyst and reduce the average pore size of the catalyst, thereby effectively improving the selectivity of reaction products such as high-value monocyclic aromatic hydrocarbons (benzene, toluene, xylene) in the catalytic reaction.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention uses a catalyst prepared by compounding a specific type of molecular sieve with metal gallium to achieve a better catalytic effect, increase the yield of aromatic compounds, and also have a higher selectivity for high-value reaction products such as monocyclic aromatic hydrocarbons.

[0029] (2) The present invention applies a metal gallium-loaded molecular sieve catalyst to the efficient catalytic pyrolysis of waste epoxy resin, thereby obtaining a high selectivity and yield of aromatic compounds, while achieving the clean disposal and resource utilization of waste epoxy resin.

[0030] (3) The catalyst prepared by the present invention still has good catalytic activity after multiple pyrolysis cycles and regeneration, and has high practical value. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] In the examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0033] Example 1

[0034] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0035] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0036] The relative contents of various chemicals in the pyrolysis products were analyzed by gas chromatography-mass spectrometry, and the relative content of aromatic compounds in the pyrolysis products was calculated to be 56.3%, of which the relative content of monocyclic aromatic hydrocarbons was 25.5% and the relative content of polycyclic aromatic hydrocarbons was 30.8%. See Table 1.

[0037] Example 2

[0038] The ZSM-5 zeolite molecular sieve was calcined at 450° C. for 3 h in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 h, and then directly dried, and then calcined at 550° C. for 6 h in an air atmosphere to obtain a catalyst;

[0039] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:1 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and the pyrolysis atmosphere was nitrogen for 20s to obtain aromatic compounds.

[0040] Example 3

[0041] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, then uniformly dispersed in a gallium nitrate aqueous solution containing gallium element equivalent to 1% of the molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0042] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:5 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and the pyrolysis atmosphere was helium for 20s to obtain aromatic compounds.

[0043] Example 4

[0044] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 0.1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0045] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0046] Example 5

[0047] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 5% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0048] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0049] Example 6

[0050] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing gallium elements equivalent to 10% of the mass of the ZSM-5 zeolite molecular sieve (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0051] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0052] Example 7

[0053] The Y-zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the Y-zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0054] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0055] Example 8

[0056] The β-zeolite molecular sieve was calcined at 550° C. for 3 h in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing gallium element equivalent to 1% of the mass of the β-zeolite molecular sieve (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 h, and then directly dried, and then calcined at 500° C. for 6 h in an air atmosphere to obtain a catalyst;

[0057] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0058] Example 9

[0059] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0060] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 500°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0061] Example 10

[0062] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0063] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 800°C and a heating rate of 10 4 ℃ / s and the pyrolysis atmosphere was nitrogen for 20s to obtain aromatic compounds.

[0064] Embodiment 11

[0065] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0066] The 50-mesh waste epoxy resin building materials and the catalyst were fully mixed in a mass ratio of 1:10 and pyrolyzed at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0067] Example 12

[0068] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing gallium elements equivalent to 10% of the mass of the ZSM-5 zeolite molecular sieve (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0069] The 200-mesh waste epoxy resin building materials and the catalyst were fully mixed in a mass ratio of 1:10 and pyrolyzed at a temperature of 600°C and a heating rate of 10 4 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0070] Embodiment 13

[0071] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0072] A 100-mesh waste epoxy resin fan blade and a catalyst were fully mixed in a mass ratio of 1:10, and co-pyrolyzed for 20 seconds at a pyrolysis temperature of 600°C, a heating rate of 10°C / s, and an argon atmosphere to obtain aromatic compounds.

[0073] Embodiment 14

[0074] The ZSM-5 zeolite molecular sieve was calcined at 550°C for 3 hours in an air atmosphere, and then uniformly dispersed in a gallium nitrate aqueous solution containing 1% gallium element of the ZSM-5 zeolite molecular sieve mass (ensuring that the solution completely wets the molecular sieve), ultrasonically dispersed at room temperature for 5 hours, and then directly dried, and then calcined at 500°C for 6 hours in an air atmosphere to obtain a catalyst;

[0075] The 100-mesh waste epoxy resin fan blades and the catalyst were fully mixed in a mass ratio of 1:10 and heated at a temperature of 600°C and a heating rate of 10 2 ℃ / s and argon as the pyrolysis atmosphere for 20s to obtain aromatic compounds.

[0076] Comparative Example 1

[0077] Compared with Example 1, the only difference of this comparative example is that no catalyst is added during the pyrolysis process.

[0078] The preparation method is similar to that of Example 1.

[0079] Comparative Example 2

[0080] Compared with Example 1, the only difference of this comparative example is that the catalyst is a ZSM-5 zeolite molecular sieve that has not been treated with gallium loading.

[0081] The preparation method is similar to that of Example 1.

[0082] Comparative Example 3

[0083] Compared with Example 1, the only difference of this comparative example is that the molecular sieve selected is MCM-41 molecular sieve.

[0084] The preparation method is similar to that of Example 1.

[0085] Comparative Example 4

[0086] Compared with Example 1, the only difference of this comparative example is that the molecular sieve selected is ZSM-22 molecular sieve.

[0087] The preparation method is similar to that of Example 1.

[0088] Comparative Example 5

[0089] Compared with Example 1, the only difference of this comparative example is that the content of gallium element is 12% of the mass of ZSM-5 molecular sieve.

[0090] The preparation method is similar to that of Example 1.

[0091] Comparative Example 6

[0092] Compared with Example 1, the only difference of this comparative example is that the co-pyrolysis temperature is 400°C.

[0093] The preparation method is similar to that of Example 1.

[0094] Comparative Example 7

[0095] Compared with Example 1, the only difference of this comparative example is that no calcination is performed after drying during the catalyst preparation process.

[0096] The preparation method is similar to that of Example 1.

[0097] The relative contents of various chemicals in the pyrolysis products were analyzed by gas chromatography-mass spectrometry, and the relative content of aromatic compounds in the pyrolysis products was calculated to be 36.4%, of which the relative content of monocyclic aromatic hydrocarbons was 8.2% and the relative content of polycyclic aromatic hydrocarbons was 28.2%.

[0098] Test Example 1: Content Determination

[0099] The relative contents of various chemicals in the pyrolysis products of Examples 1 to 14 and Comparative Examples 1 to 6 were analyzed by gas chromatography-mass spectrometry, and the relative contents of aromatic compounds, monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons in the pyrolysis products were calculated. The results are shown in Table 1.

[0100] Table 1 Relative contents of aromatic compounds, monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons in each group

[0101]

[0102] From the data in Table 1, it can be seen that Examples 1 to 14 of the present invention have a relatively high aromatic compound yield, which can reach up to 56.3%, and have a relatively high selectivity for monocyclic aromatic hydrocarbons.

[0103] In Comparative Example 1, no catalyst was added, and the content of aromatic compounds obtained was only 1.6%, and the content of monocyclic aromatic hydrocarbons accounted for only 0.3% of it; in Comparative Example 2, a catalyst without gallium metal loading was used, and although the content of aromatic compounds obtained was relatively high, the content of monocyclic aromatic hydrocarbons contained therein was only 8.8%; in Comparative Examples 3 and 4, other types of molecular sieves were used for gallium metal loading, and the catalytic effect of the obtained catalysts was poor; the gallium metal content in the catalyst obtained in Comparative Example 5 was too high, and the yield of aromatic compounds obtained by the final reaction was reduced; the co-pyrolysis temperature selected in Comparative Example 6 was relatively low, and the content of aromatic compounds obtained by the final catalysis was significantly lower than that in the embodiment; in Comparative Example 7, during the preparation process of the catalyst, no calcination operation was performed after drying, and the catalytic performance and selectivity for monocyclic aromatic hydrocarbons of the obtained catalyst were worse than those in the embodiment.

[0104] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing an aromatic compound, characterized in that: The following steps are involved: The raw materials and the catalyst are mixed and co-pyrolyzed in an oxygen-free environment to prepare aromatic compounds; The mass ratio of the raw material to the catalyst is 1:(1-10); The raw material is waste epoxy resin; The reaction conditions of the co-pyrolysis are: co-pyrolysis at 600°C, with a heating rate of 10 to 10 4 ℃ / s, the holding time of co-pyrolysis is 5 to 60s; The preparation method of the catalyst comprises the following steps: The molecular sieve is calcined for the first time, then dispersed in a gallium nitrate aqueous solution, ultrasonically dispersed at room temperature, dried, and calcined for the second time to obtain a catalyst; The molecular sieve is one of ZSM-5 zeolite, Y-zeolite and β-zeolite; The mass of gallium element in the gallium nitrate aqueous solution is 0.1% to 10% of the mass of the molecular sieve.

2. The method for preparing an aromatic compound according to claim 1, characterized in that: The preparation method of the catalyst comprises at least one of the following (1) to (3): (1) The first calcination conditions are: calcination in an air atmosphere at a temperature of 450 to 550° C. for 1 to 12 hours; (2) The second calcination is carried out in an air atmosphere at a temperature of 500 to 550° C. for 1 to 12 hours; (3) The ultrasonic dispersion time is 2 to 12 hours.

3. The method for preparing an aromatic compound according to claim 1, characterized in that: At least one of the following (1) to (2): (1) The particle size of the raw material is 50 to 200 mesh; (2) The oxygen-free environment is an environment in which there is nitrogen, argon or helium atmosphere.

4. The method for preparing an aromatic compound according to claim 1, characterized in that: The aromatic compounds include monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons.

5. The method for preparing an aromatic compound according to claim 1, characterized in that: The catalyst is recovered by calcination after the co-pyrolysis reaction is completed.

Images