Ce / hzsm-5 catalyst, its preparation method and application

Abstract

The application provides a Ce / HZSM-5 catalyst and a preparation method and application thereof, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 1-2 wt% based on 100% of the mass of the Ce / HZSM-5 catalyst. The mass fraction of Ce in the Ce / HZSM-5 catalyst provided in the application is 1-2 wt%, and the Ce loaded on the HZSM-5 can not only adjust the acidity of the Ce / HZSM-5 catalyst, but also can avoid the accumulation of Ce in the zeolite channel of the HZSM-5, so as to reduce the pore volume and pore size of the Ce / HZSM-5 catalyst, so that the Ce / HZSM-5 catalyst has high activity and selectivity to hydrocarbons, and the conversion rate of oxygen-containing compounds in PET cracking oil is improved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and relates to a Ce / HZSM-5 catalyst, and more particularly to a Ce / HZSM-5 catalyst, its preparation method and application. Background Technology

[0002] Photovoltaic modules are the most crucial components of photovoltaic power plants, with a typical lifespan of 20-30 years. With the rapid development of the photovoltaic industry, the number of waste photovoltaic modules is also constantly increasing, and it is estimated that by 2050, the global amount of waste photovoltaic modules will reach 78 million tons. These waste photovoltaic modules are mainly composed of materials such as glass, EVA, solar cells, and TPT backsheets. PET (polyethylene terephthalate) is a polymer widely used in synthetic fibers and plastic materials, accounting for approximately 80% of TPT backsheets. Therefore, the amount of PET waste in waste photovoltaic modules is considerable, and if it is not effectively recycled and utilized, it will cause serious resource waste and environmental pollution. To effectively recycle and utilize PET waste, a feasible method is to thermally crack it to obtain cracked oil containing components such as aromatic hydrocarbons, olefins, and oxygen-containing compounds. However, cracked oil contains a high proportion of oxygen-containing compounds (alcohols, carboxylic acids, benzoic acid, terephthalic acid, and their derivatives), which reduces the quality of the pyrolysis oil and makes it unsuitable for direct use in engine combustion. Therefore, the fuel must be improved through a catalytic reforming process. Reforming methods include hydrogenation, deoxygenation, aromatization, and cyclization of unsaturated functional groups, particularly the breaking of C, CO, and CO bonds.

[0003] HZSM-5 molecular sieve is a commonly used catalyst with advantages such as large specific surface area, unique pore structure, tunable surface acidity, high selectivity, and strong adsorption capacity. Most oxygen-containing compounds can migrate along the channels of HZSM-5 to the active acid sites. HZSM-5 molecular sieve also possesses... Acid centers and Lewis acid centers in catalysis Acid centers are more likely to participate in catalytic deoxygenation reactions. Through reactions such as dehydration, cracking, aromatization, isomerization, oligomerization, decarboxylation, and dealkylation, the presence of acidic centers in the catalyst makes it easier to break and separate the C-C and CO bonds in the reactants. Hydrocarbons and coke are also produced with the help of acidic centers on the catalyst. Therefore, the acidity of the catalyst should be just right to produce optimal hydrocarbon yields while reducing the polymerization of more hydrocarbons into coke material, avoiding clogging the pores and covering the active acid sites of the HZSM-5 structure, which would reduce the activity and selectivity for hydrocarbons. However, the acidity of HZSM-5 molecular sieve catalysts disclosed in the prior art is difficult to control, resulting in low activity and selectivity for hydrocarbons.

[0004] CN111085253A discloses a method for preparing an HZSM-5 catalyst simultaneously supported on Mn and Ce. The steps are as follows: Mn(NO3)4 and Ce(NO3)4 are dissolved in deionized water, HZSM-5 molecular sieve is added, and the mixture is impregnated for 4–6 h. The mixture is then dried in an oven at 75–85 °C for 25–27 h. The resulting precursor is calcined in a muffle furnace at 485–495 °C for 7–8 h, and then cooled to obtain the final product. This method is simple, rapid, and easy to operate. The prepared catalyst has a large number of surface-chemically adsorbed oxygen species, which contribute to the oxidation and combustion of carbon soot, thus exhibiting high catalytic activity for carbon soot combustion.

[0005] CN101757943A discloses a catalyst for the hydrogenation of carbon dioxide to methanol and its preparation method. Using HZSM-5 molecular sieve as a support and cerium-zirconium as an auxiliary agent, a Cu-Zn-Ce-Zr-HZSM-5 catalyst for the hydrogenation of carbon dioxide to methanol is prepared by a co-current co-precipitation impregnation method. The Cu / Zn molar ratio is 2–4:1, the Ce / Zr molar ratio is 1–3:1, the Cu-Zn mass content is 30%–70%, and the HZSM-5 mass content is 5%–50%. This patent has the advantages of: simple catalyst preparation process, no pollution, low energy consumption and production cost; high catalyst strength and long lifespan; it can significantly increase the economic efficiency of CO2 chemical utilization, achieving the goal of energy conservation, emission reduction, and turning waste into treasure.

[0006] Currently available HZSM-5 molecular sieve catalysts all have certain drawbacks, including difficulty in controlling acidity and low activity and selectivity for hydrocarbons, resulting in low conversion rates of oxygen-containing compounds in PET cracking oil. Therefore, developing a novel Ce / HZSM-5 catalyst and its preparation method is crucial. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a Ce / HZSM-5 catalyst, its preparation method, and its application. The Ce / HZSM-5 catalyst provided in this invention contains 1-2 wt% Ce. The Ce supported on HZSM-5 not only regulates the acidity of the Ce / HZSM-5 catalyst but also prevents Ce from accumulating in the zeolite channels of HZSM-5, thus avoiding a reduction in the pore volume and pore size of the Ce / HZSM-5 catalyst. This results in the Ce / HZSM-5 catalyst exhibiting high activity and selectivity for hydrocarbons, thereby improving the conversion rate of oxygen-containing compounds in PET cracking oil.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a Ce / HZSM-5 catalyst, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 1 to 2 wt%, based on the mass of the Ce / HZSM-5 catalyst.

[0010] The Ce / HZSM-5 catalyst of the present invention has a Ce mass fraction of 1 to 2 wt%, for example, it can be 1 wt%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.7%, 1.8%, 1.9% or 2 wt%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0011] Because Ce exhibits good catalytic activity in catalytic deoxygenation reactions, and because of their small particle size, they can penetrate into the interior of zeolite channels, reducing... The density of acid sites. Therefore, in this application, Ce was used to support HZSM-5 to obtain a Ce / HZSM-5 catalyst.

[0012] However, if only a small amount of Ce is loaded on HZSM-5, it cannot effectively interact with the active sites of HZSM-5, thus failing to regulate the acidity of Ce / HZSM-5. If too much Ce is loaded on HZSM-5, Ce will accumulate in the zeolite channels of HZSM-5, significantly reducing the pore volume and pore size of Ce / HZSM-5, limiting the diffusion of reactants and products in the channels, and leading to the deactivation of Ce / HZSM-5.

[0013] The Ce / HZSM-5 catalyst provided in this invention has a Ce mass fraction of 1-2 wt%. The Ce supported on HZSM-5 can both adjust the acidity of the Ce / HZSM-5 catalyst and prevent the Ce from accumulating in the zeolite channels of HZSM-5, thus avoiding the reduction of the pore volume and pore size of the Ce / HZSM-5 catalyst. This makes the Ce / HZSM-5 catalyst have high activity and selectivity for hydrocarbons, thereby improving the conversion rate of oxygen-containing compounds in PET cracking oil.

[0014] In a second aspect, the present invention provides a method for preparing the Ce / HZSM-5 catalyst described in the first aspect, the method comprising:

[0015] A Ce salt solution is mixed with HZSM-5, the mixing process including isothermal heating and ultrasonic cavitation to obtain a mixed solution, which is then heat-treated to obtain a Ce / HZSM-5 catalyst.

[0016] If Ce salt solution is simply used directly on HZSM-5, most of the Ce salt solution will be adsorbed on the surface of silicon oxide, with only a small amount entering the tetracoordinate aluminum sites. This results in a low utilization efficiency of the active components in the Ce salt solution.

[0017] In this invention, ultrasonic cavitation is performed simultaneously with isothermal heating to enhance the impregnation of HZSM-5 with Ce salt solution, allowing the Ce precursor to effectively penetrate into the inner surface of the catalyst and reducing [the following text is incomplete and likely refers to a different process:] The number of strong acid sites allows for the adjustment of the acidity of the Ce / HZSM-5 catalyst, thereby enhancing the activity and selectivity of the Ce / HZSM-5 catalyst for hydrocarbons and improving the conversion rate of oxygen-containing compounds in PET cracking oil.

[0018] Preferably, the mass ratio of Ce salt to HZSM-5 in the Ce salt solution is (0.024 to 0.048):1, for example, it can be 0.024:1, 0.026:1, 0.028:1, 0.03:1, 0.032:1, 0.034:1, 0.036:1, 0.038:1, 0.04:1, 0.042:1, 0.044:1, 0.046:1 or 0.048:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the mass ratio of the solvent to HZSM-5 in the Ce salt solution is (15-20):1, for example, it can be 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the method for preparing the Ce salt solution is as follows: placing the Ce salt in water and dissolving it by stirring.

[0021] Preferably, the preparation method further includes drying and cooling HZSM-5 sequentially before mixing.

[0022] Preferably, the drying temperature is 105-120°C and the drying time is 10-14 hours.

[0023] The drying temperature described in this invention is 105 to 120°C, for example, it can be 105°C, 110°C, 115°C or 120°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] The drying time described in this invention is 10 to 14 hours, for example, 10 hours, 11 hours, 12 hours, 13 hours or 14 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the silicon-to-aluminum ratio in the HZSM-5 is (20-30):1, for example, it can be 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1 or 30:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the mixing time is 30 to 90 minutes, for example, it can be 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes or 90 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the temperature of the constant temperature heating is 60 to 100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the isothermal heating is carried out in a jacketed glass reactor.

[0029] Preferably, the constant temperature heating includes constant temperature oil bath heating.

[0030] Preferably, the heating medium used in the constant temperature oil bath includes any one or a combination of at least two of dimethyl silicone oil, methyl silicone oil, or benzyl silicone oil. Typical but non-limiting combinations include a combination of dimethyl silicone oil and methyl silicone oil, a combination of methyl silicone oil and benzyl silicone oil, or a combination of dimethyl silicone oil, methyl silicone oil, and benzyl silicone oil.

[0031] Preferably, the mixing further includes stirring performed simultaneously with isothermal heating and ultrasonic cavitation.

[0032] Preferably, the stirring speed is 300 to 900 rpm, for example, it can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm or 900 rpm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0033] Preferably, the power of the ultrasonic cavitation is 300 to 600W, for example, it can be 300W, 350W, 400W, 450W, 500W, 550W or 600W, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the ultrasonic cavitation is performed using an external ultrasonic transmitter.

[0035] Preferably, the mixing and the heat treatment are further combined by drying.

[0036] Preferably, the drying temperature is 105–120°C and the drying time is 10–14 hours.

[0037] The drying temperature described in this invention is 105 to 120°C, for example, it can be 105°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] The drying time described in this invention is 10 to 14 hours, for example, it can be 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours or 14 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the heat treatment includes sequential heating and holding.

[0040] Preferably, the heating rate is 1 to 10 °C / min, for example, it can be 1 °C / min, 2 °C / min, 3 °C / min, 4 °C / min, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min or 10 °C / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 4 to 6 °C / min.

[0041] Preferably, the endpoint temperature of the heating is 550-650°C, for example, it can be 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C or 650°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 590-610°C.

[0042] Preferably, the heat preservation time is 3 to 5 hours, for example, it can be 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours or 5 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 3.5 to 4.5 hours.

[0043] As a preferred embodiment of the preparation method of the present invention, the preparation method includes:

[0044] (1) Mixing Ce salt solution with HZSM-5, wherein the mixing includes constant heating at 60-100°C while ultrasonic cavitation at a power of 300-600W and stirring at a speed of 300-900rpm, wherein the mixing time is 30-90min, to obtain a mixed solution; wherein the mass ratio of Ce salt to HZSM-5 in the Ce salt solution is (0.024-0.048):1, the mass ratio of solvent to HZSM-5 is (15-20):1, and the silicon-aluminum ratio in HZSM-5 is (20-30):1;

[0045] (2) The mixture obtained in step (1) is dried, and then heated to 550-650℃ at a rate of 1-10℃ / min and kept at that temperature for 3-5h to obtain Ce / HZSM-5 catalyst.

[0046] Thirdly, the present invention provides an application of the Ce / HZSM-5 catalyst described in the first aspect, wherein the Ce / HZSM-5 catalyst is used to convert oxygen-containing compounds in waste photovoltaic module PET cracking oil into gasoline-grade hydrocarbons.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The Ce / HZSM-5 catalyst provided in this invention has a Ce mass fraction of 1-2 wt%. The Ce supported on HZSM-5 can both adjust the acidity of the Ce / HZSM-5 catalyst and prevent the Ce from accumulating in the zeolite channels of HZSM-5, thus avoiding the reduction of the pore volume and pore size of the Ce / HZSM-5 catalyst. This makes the Ce / HZSM-5 catalyst have high activity and selectivity for hydrocarbons, thereby improving the conversion rate of oxygen-containing compounds in PET cracking oil. Attached Figure Description

[0049] Figure 1 This refers to the preparation apparatus used in the preparation method of Ce / HZSM-5 catalyst in Example 1 of this invention.

[0050] Figure 2The NH3-TPD spectra of the Ce / HZSM-5 catalyst in Examples 1 and 2 of this invention and the HZSM-5 catalyst provided in Comparative Example 4 are shown.

[0051] Among them, 1-ultrasonic transmitter; 2-transducer; 3-iron frame; 4-amplifier rod; 5-jacketed glass reactor; 6-oil circulation; 7-constant temperature circulation device; 8-glass stirring rod. Detailed Implementation

[0052] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0053] Example 1

[0054] This embodiment provides a Ce / HZSM-5 catalyst, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 1 wt%.

[0055] The preparation method of the Ce / HZSM-5 catalyst includes:

[0056] (1) Aqueous solution of cerium nitrate and HZSM-5 are mixed. The mixing includes constant heating at 80°C, ultrasonic cavitation at 300W, and stirring at 600rpm. The mixing time is 30min to obtain a mixed solution. The mass ratio of cerium nitrate to HZSM-5 in the aqueous solution of cerium nitrate is 0.024:1, the mass ratio of water to HZSM-5 is 18:1, and the silicon-aluminum ratio in HZSM-5 is 25.

[0057] (2) The mixture obtained in step (1) is dried, and then heated to 600°C at a rate of 5°C / min and kept at that temperature for 4 hours to obtain Ce / HZSM-5 catalyst.

[0058] The preparation apparatus used in the preparation method described in this embodiment is as follows: Figure 1 As shown, Figure 1 The ultrasonic transmitter 1 is used to provide ultrasonic waves to achieve ultrasonic cavitation. The transducer 2 is used to convert electrical energy into mechanical vibration energy. The iron frame 3 is used to fix the transducer 2. The amplitude transformer 4 is used to adjust the amplitude of the ultrasonic waves. The jacketed glass reactor 5 is used as a reaction vessel. Constant temperature heating is achieved through oil circulation 6 and constant temperature circulation device 7. Stirring is achieved using a glass plate.

[0059] Example 2

[0060] This embodiment provides a Ce / HZSM-5 catalyst, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 2 wt%, based on the mass of the Ce / HZSM-5 catalyst.

[0061] The preparation method of the Ce / HZSM-5 catalyst includes:

[0062] (1) Mixing an aqueous solution of cerium nitrate with HZSM-5, wherein the mixing includes constant heating at 80°C while ultrasonic cavitation is performed at a power of 300W and stirring at a speed of 700rpm, and the mixing time is 30min to obtain a mixed solution; the mass ratio of cerium nitrate to HZSM-5 in the aqueous solution of cerium nitrate is 0.048:1, the mass ratio of water to HZSM-5 is 15:1, and the silicon-aluminum ratio in HZSM-5 is 25:1;

[0063] (2) The mixture obtained in step (1) is dried, and then heated to 600°C at a rate of 5°C / min and kept at that temperature for 4 hours to obtain Ce / HZSM-5 catalyst.

[0064] Example 3

[0065] This embodiment provides a Ce / HZSM-5 catalyst, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 1.5 wt%.

[0066] The preparation method of the Ce / HZSM-5 catalyst includes:

[0067] (1) Mixing an aqueous solution of cerium nitrate with HZSM-5, wherein the mixing includes constant heating at 60°C while ultrasonic cavitation is performed at a power of 500W and stirring at a speed of 300rpm, and the mixing time is 90min to obtain a mixed solution; the mass ratio of cerium nitrate to HZSM-5 in the aqueous solution of cerium nitrate is 0.035:1, the mass ratio of water to HZSM-5 is 20:1, and the silicon-aluminum ratio in HZSM-5 is 30:1;

[0068] (2) The mixture obtained in step (1) is dried, and then heated to 550°C at a rate of 1°C / min and kept at that temperature for 5 hours to obtain Ce / HZSM-5 catalyst.

[0069] Example 4

[0070] This embodiment provides a Ce / HZSM-5 catalyst, wherein the mass fraction of Ce in the Ce / HZSM-5 catalyst is 1.8 wt%.

[0071] The preparation method of the Ce / HZSM-5 catalyst includes:

[0072] (1) Aqueous solutions of cerium nitrate and HZSM-5 are mixed. The mixing includes constant heating at 100°C, ultrasonic cavitation at 600W, and stirring at 900rpm. The mixing time is 60min to obtain a mixed solution. The mass ratio of cerium nitrate to HZSM-5 in the aqueous solution of cerium nitrate is 0.043:1, the mass ratio of water to HZSM-5 is 20:1, and the silicon-aluminum ratio in HZSM-5 is 25:1.

[0073] (2) The mixture obtained in step (1) is dried, and then heated to 650°C at a rate of 10°C / min and kept at that temperature for 3 hours to obtain Ce / HZSM-5 catalyst.

[0074] Example 5

[0075] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as that in Example 1 except that it is heated at a constant temperature of 40°C.

[0076] Example 6

[0077] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as that in Example 1 except that it is heated at 140°C.

[0078] Example 7

[0079] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as in Example 1 except that ultrasonic cavitation is performed at a power of 200W in the preparation method of the Ce / HZSM-5 catalyst.

[0080] Example 8

[0081] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as in Example 1 except that ultrasonic cavitation is performed at a power of 800W in the preparation method of the Ce / HZSM-5 catalyst.

[0082] Example 9

[0083] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as in Example 1 except that the mixing time in the preparation method of the Ce / HZSM-5 catalyst is 15 min.

[0084] Example 10

[0085] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as in Example 1 except that the mixing time in the preparation method of the Ce / HZSM-5 catalyst is 120 min.

[0086] Example 11

[0087] This embodiment provides a Ce / HZSM-5 catalyst, which is the same as that in Example 1 except that the silicon-aluminum ratio in HZSM-5 is 15:1.

[0088] Example 12

[0089] This embodiment provides a Ce / HZSM-5 catalyst, which is identical to that of Example 1 except that the silicon-to-aluminum ratio in the HZSM-5 is 40:1.

[0090] Comparative Example 1

[0091] This comparative example provides a Ce / HZSM-5 catalyst, except that the mass fraction of Ce in the Ce / HZSM-5 catalyst is 0.5wt%, that is, the mass ratio of Ce salt to HZSM-5 in the Ce salt solution in step (1) of the preparation method of the Ce / HZSM-5 catalyst is 0.0156:1, and all other aspects are the same as in Example 1.

[0092] Comparative Example 2

[0093] This comparative example provides a Ce / HZSM-5 catalyst, except that the mass fraction of Ce in the Ce / HZSM-5 catalyst is 3wt%, that is, the mass ratio of Ce salt to HZSM-5 in the Ce salt solution in step (1) of the preparation method of the Ce / HZSM-5 catalyst is 0.0958:1, and all other aspects are the same as in Example 1.

[0094] Comparative Example 3

[0095] This comparative example provides a Ce / HZSM-5 catalyst, which is the same as in Example 1 except that the ultrasonic cavitation performed simultaneously with isothermal heating in step (1) of the preparation method of the Ce / HZSM-5 catalyst is omitted.

[0096] Comparative Example 4

[0097] This comparative example provides an HZSM-5 catalyst, which is the HZSM-5 catalyst from Example 1.

[0098] The Ce / HZSM-5 catalysts provided in Examples 1 and 2 and the HZSM-5 catalyst provided in Comparative Example 4 were subjected to NH3-TPD tests, and the curves showing the change in desorbed gas concentration with temperature are shown below. Figure 2 As shown;

[0099] The specific surface area, pore volume, pore size and total acid content of Ce / HZSM-5 catalysts provided in Examples 1-12, Comparative Examples 1-3 and HZSM-5 catalysts provided in Comparative Example 4 were tested. The test results are shown in Table 1.

[0100] The specific surface area is determined by nitrogen adsorption-desorption experiment (BET method) (GB / T19587-2017 "Determination of specific surface area of ​​solid substances by gas adsorption BET method").

[0101] The pore volume was determined by nitrogen adsorption-desorption experiment (t-plot method);

[0102] The aperture measurement method is as follows: the aperture information value is calculated using the BET method;

[0103] The test method for total acidity is as follows: NH3-TPD experiment determination, standard pulse peak calibration method: compare the sample signal peak area with the standard pulse peak area, calculate the NH3 volume of the sample peak area, and then calculate the "total acidity";

[0104] The Ce / HZSM-5 catalysts provided in Examples 1-12, Comparative Examples 1-3, and the HZSM-5 catalyst provided in Comparative Example 4 were used to convert oxygen-containing compounds in PET cracking oil. The conversion method was hydrodeoxygenation. The conversion rates of oxygen-containing compounds in PET cracking oil were tested and are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] From Table 1 and Figure 2 We can obtain:

[0109] (1) The Ce / HZSM-5 catalysts provided in Examples 1 to 4 have a low total acid content and exhibit a high conversion rate of oxygen-containing compounds in PET cracking oil.

[0110] (2) By comparing Example 1 with Examples 5 and 6, it can be seen that the temperature of isothermal heating in step (1) of the preparation method of Ce / HZSM-5 catalyst in this invention will affect the performance of Ce / HZSM-5 catalyst. When the isothermal heating temperature is too low, the specific surface area, pore volume, pore size, total acid content and conversion rate of oxygen-containing compounds of Ce / HZSM-5 catalyst will decrease. This is because the dissolution and dispersion of Ce salt are insufficient at the low heating temperature, and Ce species are deposited in the pore openings and channels of molecular sieve, causing blockage of molecular sieve channels and smaller pore size, thereby reducing the exposure of effective pores and active sites. When the isothermal heating temperature is too high, the conversion rate of oxygen-containing compounds will decrease. This is because the Ce sintering or molecular sieve structure is destroyed due to excessive temperature, thereby reducing the performance of the catalyst.

[0111] (3) By comparing Example 1 with Examples 7 and 8, it can be seen that the power of ultrasonic cavitation in step (1) of the preparation method of Ce / HZSM-5 catalyst in this invention will affect the performance of Ce / HZSM-5 catalyst. When the power of ultrasonic cavitation is too low, the conversion rate of oxygen-containing compounds will be reduced. This is because the low ultrasonic cavitation power cannot generate enough local high temperature and high pressure to promote the uniform dispersion and loading of Ce species, which may block some pores. When the power of ultrasonic cavitation is too high, the conversion rate of oxygen-containing compounds will be reduced. This is because the excessive ultrasonic cavitation will destroy the structure of HZSM-5 molecular sieve, thereby reducing the performance of the catalyst.

[0112] (4) By comparing Example 1 with Examples 9 and 10, it can be seen that the mixing time in step (1) of the preparation method of Ce / HZSM-5 catalyst in this invention will affect the performance of Ce / HZSM-5 catalyst. When the mixing time is too short, the specific surface area, pore volume, pore size, total acid content and conversion rate of oxygen-containing compounds of Ce / HZSM-5 catalyst will decrease. This is because the interaction and dispersion between Ce salt and HZSM-5 are insufficient due to insufficient mixing time, resulting in uneven loading and blockage of pores by undispersed Ce salt. If the mixing time is too long, it may lead to the destruction of molecular sieve structure or excessive dispersion of Ce salt, thereby reducing the performance of catalyst.

[0113] (5) By comparing Example 1 with Examples 13 and 14, it can be seen that the silicon-aluminum ratio in HZSM-5 in step (1) of the preparation method of Ce / HZSM-5 catalyst in this invention will affect the performance of Ce / HZSM-5 catalyst. When the silicon-aluminum ratio is low, the specific surface area, pore volume, pore size, total acid content and conversion rate of oxygen-containing compounds of Ce / HZSM-5 catalyst will decrease. This is because HZSM-5 with a low silicon-aluminum ratio has more aluminum content, which leads to an increase in acidic sites of the catalyst. However, this will also lead to a decrease in the stability of the catalyst structure and an easy collapse of the pore structure, thereby reducing the specific surface area and pore volume. High acidity will promote non-selective reactions and reduce the conversion rate of oxygen-containing compounds. When the silicon-aluminum ratio is high, the channels of the molecular sieve may be narrower and the pore walls may be thicker. This is not conducive to the diffusion of reactants and the contact efficiency of the catalyst. At the same time, aluminum is the main source of acidic sites in the molecular sieve. The reduction of aluminum content will reduce the total acid content of the catalyst and affect its catalytic activity.

[0114] (6) By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that if only a small amount of Ce is loaded on HZSM-5, it cannot effectively interact with the active sites of HZSM-5, thus making it impossible to regulate the acidity of Ce / HZSM-5; if too much Ce is loaded on HZSM-5, Ce will accumulate in the zeolite channels of HZSM-5, significantly reducing the pore volume and pore size of Ce / HZSM-5, limiting the diffusion of reactants and products in the channels, and causing Ce / HZSM-5 to deactivate.

[0115] (7) By comparing Example 1 and Comparative Example 3, it can be seen that the ultrasonic cavitation carried out simultaneously with isothermal heating in step (1) of the preparation method of Ce / HZSM-5 catalyst in this invention will affect the performance of Ce / HZSM-5 catalyst. When ultrasonic cavitation is omitted, the specific surface area, pore volume, pore size, total acid content and conversion rate of oxygen-containing compounds of Ce / HZSM-5 catalyst will decrease. This is because the lack of ultrasonic cavitation process results in uneven dispersion of Ce species on HZSM-5, causing some Ce species to accumulate in the pores, causing pore blockage and covering the active sites.

[0116] (8) By comparing Examples 1 and 2 with Comparative Example 4, it can be seen that the low-temperature desorption peak at 200°C is related to the release of NH3 from Lewis centers (weak acidic centers) such as aluminum outside the framework, while the high-temperature desorption peak at 412°C is related to the release of NH3 from Bronsted acidic centers (strong acidic centers) of aluminum outside the framework. The peak area represents the number of acid sites, and the peak temperature represents the acid strength. Therefore, compared with the original HZSM-5, the Ce / HZSM-5 catalyst provided in this invention, when loaded with a low amount of 1wt% and 2wt% Ce, has a decrease in the number and strength of weak acid and strong acid centers to varying degrees, thereby reducing the total acidity, especially the Bronsted acid sites are significantly reduced.

[0117] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An application of a Ce / HZSM-5 catalyst, characterized in that, The Ce / HZSM-5 catalyst is used to convert oxygen-containing compounds in waste photovoltaic module PET cracking oil into gasoline-grade hydrocarbons. The mass fraction of Ce in the Ce / HZSM-5 catalyst is 1~2wt%, based on the mass of the Ce / HZSM-5 catalyst.

2. An application of the Ce / HZSM-5 catalyst according to claim 1, characterized in that, The preparation method of the Ce / HZSM-5 catalyst includes: A Ce salt solution is mixed with HZSM-5, the mixing process including isothermal heating and ultrasonic cavitation to obtain a mixed solution, which is then heat-treated to obtain a Ce / HZSM-5 catalyst.

3. The application according to claim 2, characterized in that, The mass ratio of Ce salt to HZSM-5 in the Ce salt solution is (0.024~0.048):

1.

4. The application according to claim 2, characterized in that, The mass ratio of the solvent to HZSM-5 in the Ce salt solution is (15~20):

1.

5. The application according to claim 2, characterized in that, The silicon-to-aluminum ratio in the HZSM-5 is (20~30):

1.

6. The application according to claim 2, characterized in that, The mixing time is 30-90 minutes.

7. The application according to claim 2, characterized in that, The temperature for constant temperature heating is 60~100℃.

8. The application according to claim 2, characterized in that, The mixing also includes stirring that is performed simultaneously with constant temperature heating and ultrasonic cavitation.

9. The application according to claim 8, characterized in that, The stirring speed is 300~900 rpm.

10. The application according to claim 2, characterized in that, The power of the ultrasonic cavitation is 300~600W.

11. The application according to claim 2, characterized in that, The mixing process includes drying between the heat treatment and the mixing process.

12. The application according to claim 11, characterized in that, The drying temperature is 105~120℃, and the time is 10~14h.

13. The application according to claim 2, characterized in that, The heat treatment includes sequential heating and holding.

14. The application according to claim 13, characterized in that, The heating rate is 1~10℃ / min.

15. The application according to claim 13, characterized in that, The final temperature of the heating process is 550~650℃.

16. The application according to claim 13, characterized in that, The heat preservation time is 3-5 hours.

17. The application according to any one of claims 2 to 16, characterized in that, The preparation method of the Ce / HZSM-5 catalyst includes: (1) Mixing Ce salt solution with HZSM-5, wherein the mixing includes constant heating at 60~100℃ while ultrasonic cavitation at a power of 300~600W and stirring at a speed of 300~900rpm, the mixing time is 30~90min, to obtain a mixed solution; the mass ratio of Ce salt to HZSM-5 in the Ce salt solution is (0.024~0.048):1, the mass ratio of solvent to HZSM-5 is (15~20):1, and the silicon-aluminum ratio in HZSM-5 is (20~30):1; (2) The mixture obtained in step (1) is dried, and then heated to 550-650℃ at a rate of 1-10℃ / min and kept at that temperature for 3-5h to obtain Ce / HZSM-5 catalyst.

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