Tungsten oxide / mesoporous zirconia-loaded ruthenium-based catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst and a preparation method and application thereof. Compared with the prior art, the metal-acid bifunctional catalyst is constructed by loading the metal ruthenium on the tungsten oxide / mesoporous zirconium oxide, the metal ruthenium is used as a dehydrogenation site in the polyethylene hydrogenolysis reaction, an acidic site on the tungsten oxide / mesoporous zirconium oxide is responsible for forming carbocations, further cracking and isomerization are performed, and through the synergistic effect of the metal acid, the metal-acid bifunctional catalyst is obtained. The liquid product with high added value and carbon number in the diesel oil range is obtained, the isomerization degree is high, the selectivity of gas-phase products such as methane is low, and excessive consumption of hydrogen is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts, and particularly relates to a tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] The global annual output of plastic waste is more than 400 million tons, and polyolefin (PE / PP) accounts for more than 60%. It takes hundreds of years for natural degradation. At present, most of the waste plastics have not been recycled and processed, causing great harm to the ecological environment.

[0003] Traditional landfill / incineration leads to microplastic pollution and a sharp increase in carbon emissions (1.7 tons of carbon dioxide are released per ton of plastic incineration).

[0004] The performance of the regenerated plastic by the traditional mechanical method is poor, and the cost is also higher.

[0005] Chemical recycling is a promising plastic recycling and degradation technology at present, which can realize the polymerization of plastic to monomer or the selective conversion of plastic to high-value chemicals, and has been widely studied by domestic and foreign research groups. Polyolefin is essentially a hydrocarbon (C / H ratio is about 2), and its conversion to liquid fuel can realize the transformation of waste plastic to oil, which is equivalent to the addition of hundreds of millions of tons of renewable energy. At present, various methods such as pyrolysis recycling, hydrogenolysis recycling and olefin metathesis have been developed. The pyrolysis reaction temperature is too high, the product carbon number distribution is wide, and the aromatic hydrocarbon content is high, which is not suitable for liquid fuel; hydrogenolysis recycling and olefin metathesis still lack economy due to high reaction temperature or consumption of a large amount of expensive co-reactants (hydrogen or short-chain olefins, etc.), and the selectivity of shearing such as methane and the regulation of carbon number distribution are still not ideal. Therefore, the construction of a hydrogenolysis catalyst with high activity and precise shearing of polyolefin chains is the development goal in the future. SUMMARY

[0006] Therefore, the application aims to solve the technical problem by providing a tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst for thermal catalytic polyolefin hydrogenolysis, which has mild reaction conditions and is environmentally friendly. The preparation method and application of the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst also realize low selectivity of gas phase products, and the liquid phase products are concentrated in the carbon number range of gasoline and diesel, and the isoparaffin is the main product.

[0007] The application provides a tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst, which comprises a carrier and metal ruthenium supported on the carrier; the carrier comprises mesoporous zirconium oxide and tungsten oxide.

[0008] The mass of the tungsten oxide is 10% to 50% of the mass of the mesoporous zirconium oxide.

[0009] Preferably, the carrier comprises tetragonal mesoporous zirconia and tungsten oxide.

[0010] Preferably, the mass of the tungsten oxide is 20%~40% of the mass of the mesoporous zirconia.

[0011] Preferably, the loading of metallic ruthenium in the ruthenium-based catalyst is 0.1%~10%.

[0012] Preferably, the loading of metallic ruthenium in the ruthenium-based catalyst is 1%.

[0013] The present application also provides a preparation method of the above-mentioned tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst, comprising the following steps:

[0014] S1) mixing mesoporous zirconia and a tungsten source in a first solvent, and after removing the solvent, calcining to obtain a carrier;

[0015] S2) mixing the carrier and a ruthenium source in a second solvent, and after removing the solvent, heating in a reducing atmosphere for reduction treatment to obtain a tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst.

[0016] Preferably, the tungsten source is selected from one or more of ammonium metatungstate, sodium tungstate and ammonium paratungstate;

[0017] and / or, the ruthenium source is selected from one or more of ruthenium chloride, ruthenium nitrosyl nitrate and ruthenium acetylacetonate;

[0018] and / or, the first solvent and the second solvent are each independently selected from water;

[0019] and / or, the mesoporous zirconia is prepared according to the following method:

[0020] A1) mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, alcohol solvent, organic acid, inorganic acid and zirconium source to obtain a sol;

[0021] A2) heating the sol for gelation to obtain a solid;

[0022] A3) calcining the solid to obtain mesoporous zirconia.

[0023] Preferably, the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer is as shown in formula (I):

[0024] Formula (I);

[0025] wherein x, y and z are all degrees of polymerization, x is 10~30, y is 60~80, and z is 10~30;

[0026] The zirconium source is selected from one or more of zirconium n-propylate, zirconium acetate, zirconium acetylacetone and zirconium isopropylate;

[0027] And / or, the mass ratio of the polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer to the zirconium source is (1-5):9;

[0028] And / or, the mixing time in step A1) is 10-60 min;

[0029] And / or, the gelling temperature in step A2) is 40-60℃; the gelling time is 2-4 days;

[0030] And / or, the calcination temperature in step A3) is 400-600℃; the calcination time is 4-8 h.

[0031] Preferably, the calcination temperature in step S1) is 400-600℃; the calcination time is 4-8 h;

[0032] And / or, the reducing atmosphere in step S2) is hydrogen; the flow rate of the reducing atmosphere is 10-100 mL / min; the reduction treatment temperature is 300-500℃; the reduction treatment time is 1-3 h.

[0033] The application further provides an application of the above-mentioned tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst in thermal catalytic polyethylene degradation.

[0034] Compared with the prior art, the application loads metal ruthenium on tungsten oxide / mesoporous zirconia to construct a metal-acid bifunctional catalyst, in which the metal ruthenium acts as a dehydrogenation site, the acidic sites on the tungsten oxide / mesoporous zirconia are responsible for forming carbonium ions, further cracking and isomerization, through metal-acid synergistic effect, liquid products with high added value in the diesel range are obtained, the isomerization degree is high, the selectivity of gaseous products such as methane is low, and the excessive consumption of hydrogen is avoided.

[0035] The experimental results show that, by using the tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst provided by the application to prepare liquid fuel through thermal catalytic degradation of high-density polyethylene, liquid fuel with a carbon number range of C5-C 18 , and an isoparaffin ratio of nearly 90% and high added value. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The X-ray diffraction pattern of the tetragonal mesoporous zirconia obtained in Example 1 of the application;

[0037] Figure 2 The N2 adsorption-desorption spectrum of the tetragonal mesoporous zirconia obtained in Example 1 of the application;

[0038] Figure 3 The pore size distribution diagram of the tetragonal mesoporous zirconium oxide obtained in Embodiment 1 of the present application;

[0039] Figure 4 The transmission electron microscope diagram of the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst obtained in Embodiment 1 of the present application;

[0040] Figure 5 The carbon number distribution diagram of the thermocatalytic high-density polyethylene degradation product in Embodiment 2 of the present application;

[0041] Figure 6 The conversion rate diagram of the high-density polyethylene degradation under different H2 partial pressures in Embodiment 3 of the present application;

[0042] Figure 7 The time evolution test result diagram of the thermocatalytic high-density polyethylene degradation in Embodiment 4 of the present application;

[0043] Figure 8 The carbon number distribution result diagram of the thermocatalytic high-density polyethylene degradation experiment in Embodiment 6 of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0045] The present application provides a tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst, which comprises a carrier and a metal ruthenium supported on the carrier; the carrier comprises mesoporous zirconium oxide and tungsten oxide; the mass of the tungsten oxide is 10% to 50% of the mass of the mesoporous zirconium oxide.

[0046] In the present application, mesoporous zirconium oxide and tungsten oxide are used as the carrier; in a specific embodiment provided by the present application, the carrier comprises tetragonal zirconium oxide and tungsten oxide.

[0047] In a specific embodiment provided by the present application, optionally, the mass of the tungsten oxide is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% of the mass of the mesoporous zirconium oxide or a range between any two of the above values.

[0048] In a specific embodiment provided by the present application, the mass of the tungsten oxide is 20% to 40% of the mass of the mesoporous zirconium oxide.

[0049] In one specific embodiment of the present invention, the mass of the tungsten oxide is 25% of the mass of the mesoporous zirconium oxide.

[0050] In a specific embodiment of the present invention, the ruthenium loading in the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst is preferably 0.1% to 10%. Optionally, the ruthenium loading in the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst is 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of the above values.

[0051] In one specific embodiment of the present invention, the ruthenium loading in the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst is preferably 1%.

[0052] This invention constructs a metal-acid bifunctional catalyst by loading ruthenium metal onto tungsten oxide / mesoporous zirconium oxide. In the hydrogenolysis reaction of polyethylene, ruthenium metal acts as a dehydrogenation site, while the acidic sites on tungsten oxide / mesoporous zirconium oxide are responsible for forming carbocations, which are further cracked and isomerized. Through the synergistic effect of metal and acid, liquid products with high added value and carbon numbers in the diesel range are obtained, with a high degree of isomerization and low selectivity for gaseous products such as methane, thus avoiding excessive hydrogen consumption.

[0053] The present invention also provides a method for preparing the above-mentioned ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide, comprising the following steps: S1) mixing mesoporous zirconium oxide and a tungsten source in a first solvent, removing the solvent, and calcining to obtain a support; S2) mixing the support and a ruthenium source in a second solvent, removing the solvent, and heating in a reducing atmosphere for reduction treatment to obtain the ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide.

[0054] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available or self-made.

[0055] In one specific embodiment of the present invention, the mesoporous zirconia is preferably synthesized by sol-gel method using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer as a template agent.

[0056] Specifically, the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer is shown in formula (I):

[0057] Formula (I);

[0058] Wherein, x, y and z are all the polymerization degree, x is preferably 10-30, more preferably 12-28, more preferably 15-25, more preferably 18-22, and most preferably 20; y is preferably 60-80, more preferably 62-78, more preferably 65-75, more preferably 68-72, and most preferably 70; z is preferably 10-30, more preferably 12-28, more preferably 15-25, more preferably 18-22, and most preferably 20.

[0059] In a specific embodiment provided by the present application, the average molecular weight of the polyethylene oxide-polypropylene oxide-polyethylene oxide tri-block copolymer is preferably 4000-7000, more preferably 4500-6500, more preferably 4800-6200, more preferably 5000-6200, more preferably 5200-6200, more preferably 5500-6000, and most preferably 5800.

[0060] In a specific embodiment provided by the present application, the polyethylene oxide-polypropylene oxide-polyethylene oxide tri-block copolymer is P123.

[0061] In the present application, the mesoporous zirconium oxide is preferably prepared according to the following method: A1) mixing a polyethylene oxide-polypropylene oxide-polyethylene oxide tri-block copolymer, an alcohol solvent, an organic acid, an inorganic acid and a zirconium source to obtain a sol; A2) heating the sol to gel to obtain a solid; A3) calcining the solid to obtain the mesoporous zirconium oxide.

[0062] In a specific embodiment provided by the present application, the alcohol solvent can be any alcohol solvent known to those skilled in the art without special limitation, and ethanol is preferred in the present application; the organic acid can be any organic acid known to those skilled in the art without special limitation, and glacial acetic acid is preferred in the present application; the inorganic acid can be any inorganic acid known to those skilled in the art without special limitation, and hydrochloric acid is preferred in the present application; and the zirconium source can be any zirconium source known to those skilled in the art without special limitation, and organic zirconium salt is preferred in the present application, and more preferably one or more of zirconium n-propoxide, zirconium acetate, zirconium acetylacetonate and zirconium isopropoxide.

[0063] In a specific embodiment provided by the present application, the ratio of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer to the alcohol solvent is preferably (1-5) g:155 mL; alternatively, the ratio is 1 g:155 mL, 1.5 g:155 mL, 2 g:155 mL, 2.28 g:155 mL, 2.5 g:155 mL, 3 g:155 mL, 3.5 g:155 mL, 4 g:155 mL, 4.5 g:155 mL, 5 g:155 mL, or a range between any two of the foregoing ratios.

[0064] The mass ratio of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer to the zirconium source is preferably (1-5):9; alternatively, the mass ratio of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer to the zirconium source is 1:9, 1.5:9, 2:9, 2.28:9, 2.5:9, 3:9, 3.5:9, 4:9, 4.5:9, 5:9, or a range between any two of the foregoing ratios.

[0065] In a specific embodiment provided by the present application, the ratio of the organic acid to the zirconium source is preferably (0.1-1) mL:9 g; alternatively, the ratio of the organic acid to the zirconium source is 0.1 mL:9 g, 0.2 mL:9 g, 0.3 mL:9 g, 0.4 mL:9 g, 0.5 mL:9 g, 0.6 mL:9 g, 0.7 mL:9 g, 0.73 mL:9 g, 0.8 mL:9 g, 0.9 mL:9 g, 1 mL:9 g, or a range between any two of the foregoing ratios.

[0066] In a specific embodiment provided by the present application, the ratio of the inorganic acid to the zirconium source is preferably (0.5-5) mL:9 g; alternatively, the ratio of the inorganic acid to the zirconium source is 0.5 mL:9 g, 1 mL:9 g, 1.5 mL:9 g, 2 mL:9 g, 2.31 mL:9 g, 2.5 mL:9 g, 3 mL:9 g, 3.5 mL:9 g, 4 mL:9 g, 4.5 mL:9 g, 5 mL:9 g, or a range between any two of the foregoing ratios.

[0067] In a specific embodiment provided by the present application, the mixing time of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, the alcohol solvent, the organic acid, the inorganic acid, and the zirconium source is preferably 10-60 min; alternatively, the mixing time is 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, or a range between any two of the foregoing values.

[0068] In one specific embodiment provided by the present application, the temperature for gelation is preferably 40-60℃; alternatively, the temperature for gelation is 40℃, 45℃, 50℃, 55℃, 60℃ or a range between any two of the above values; the time for gelation is preferably 2-4 days; alternatively, the time for gelation is 2 days, 2.5 days, 3 days, 3.5 days, 4 days or a range between any two of the above values.

[0069] In one specific embodiment provided by the present application, the temperature for calcination of the solid is preferably 400-600℃; alternatively, the temperature for calcination of the solid is 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃ or a range between any two of the above values; the time for calcination of the solid is preferably 4-8 h; alternatively, the time for calcination of the solid is 4 h, 5 h, 6 h, 7 h, 8 h or a range between any two of the above values.

[0070] The mesoporous zirconium oxide and the tungsten source are mixed in a first solvent; the tungsten source can be any tungsten source known to those skilled in the art and is not particularly limited, and in the present application, one or more of ammonium metatungstate, sodium tungstate and ammonium paratungstate are preferred; the mass of the mesoporous zirconium oxide and the tungsten source can be selected according to the mass of tungsten oxide in the carrier; the first solvent is preferably water.

[0071] After mixing, the solvent is removed; the method for removing the solvent can be any method known to those skilled in the art and is not particularly limited, and in the present application, the solvent is preferably evaporated under the condition of water bath and vigorous stirring.

[0072] After the solvent is removed, calcination is performed to obtain the carrier; the temperature for calcination is preferably 400-600℃; alternatively, the temperature for calcination is 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃ or a range between any two of the above values; the time for calcination is preferably 4-8 h; alternatively, the time for calcination is 4 h, 5 h, 6 h, 7 h, 8 h or a range between any two of the above values.

[0073] The carrier and a ruthenium source are mixed in a second solvent; the ruthenium source can be any water-soluble ruthenium source known to those skilled in the art and is not particularly limited, and in the present application, one or more of ruthenium chloride, ruthenium nitrosyl nitrate and ruthenium acetylacetonate are preferred; the amount of the ruthenium source can be selected according to the loading amount of ruthenium metal; the second solvent is preferably water.

[0074] After mixing, the solvent is removed; the method for removing the solvent is well known to those skilled in the art and is not particularly limited, and in the present application, the solvent is preferably removed by evaporating the solvent under the condition of water bath and vigorous stirring.

[0075] After removing the solvent, reduction treatment is performed by heating in a reducing atmosphere; the reducing atmosphere is preferably hydrogen; the flow rate of the reducing atmosphere is preferably 10-100 mL / min; optionally, the flow rate of the reducing atmosphere is 10 mL / min, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, 100 mL / min, or a range between any two of the above values; the reduction treatment is preferably performed in a quartz reaction tube; the temperature of the reduction treatment is preferably 300-500℃; optionally, the temperature of the reduction treatment is 300℃, 320℃, 350℃, 380℃, 400℃, 420℃, 450℃, 480℃, 500℃, or a range between any two of the above values; the time of the reduction treatment is preferably 1-3 h; optionally, the time of the reduction treatment is 1 h, 1.5 h, 2 h, 2.5 h, 3 h, or a range between any two of the above values.

[0076] The present application also provides a use of the above tungsten oxide / mesoporous zirconia-supported ruthenium-based catalyst in thermal catalytic degradation of polyethylene.

[0077] In a specific embodiment provided by the present application, the polyethylene is preferably high-density polyethylene.

[0078] In a specific embodiment provided by the present application, the high-density polyethylene has a density of 0.941-0.965 g / mL at 25℃, more preferably 0.945-0.96 g / mL, even more preferably 0.948-0.958 g / mL, yet more preferably 0.95-0.955 g / mL, and most preferably 0.952 g / mL.

[0079] In an embodiment of the present application, the high-density polyethylene has a melt index of 1 g / 10 min to 50 g / 10 min at 25°C; optionally, the high-density polyethylene has a melt index of 1 g / 10 min, 3 g / 10 min, 5 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 15 g / 10 min, 18 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, or a range between any two of the aforementioned values.

[0080] In an embodiment of the present application, the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst has a mass of 1% to 50% of the mass of the polyethylene; optionally, the tungsten oxide / mesoporous zirconium oxide supported ruthenium-based catalyst has a mass of 1%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50% of the mass of the polyethylene, or a range between any two of the aforementioned values.

[0081] In an embodiment of the present application, the thermal catalytic polyethylene degradation is performed in a reducing atmosphere; the volume concentration of hydrogen in the reducing atmosphere is preferably 80% to 100%, more preferably 85% to 100%, even more preferably 90% to 100%, yet more preferably 95% to 100%, most preferably 97%; the pressure of the reducing atmosphere is preferably 1 to 5 MPa; optionally, the pressure of the reducing atmosphere is 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, or a range between any two of the aforementioned values.

[0082] In an embodiment of the present application, the thermal catalytic polyethylene degradation is performed at a temperature of 200°C to 300°C; optionally, the thermal catalytic polyethylene degradation is performed at a temperature of 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, or a range between any two of the aforementioned values.

[0083] In an embodiment of the present application, the thermal catalytic polyethylene degradation is performed for a time of 4 to 10 h; optionally, the thermal catalytic polyethylene degradation is performed for a time of 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, or a range between any two of the aforementioned values.

[0084] In a specific embodiment provided in the present application, the thermal catalytic polyethylene degradation obtains a high value-added liquid fuel with a C5-C18 carbon number range and an isoparaffin proportion of nearly 90%.

[0085] The present application constructs a metal-acid bifunctional catalyst by loading metal ruthenium on tungsten oxide / mesoporous zirconia, and under the synergistic effect of metal-acid in polyethylene hydrogenolysis reaction, a liquid product with high added value and a diesel range carbon number and high isomerization degree is obtained, and the selectivity of gaseous products such as methane is low, avoiding excessive consumption of hydrogen.

[0086] In order to further illustrate the present application, the tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst provided by the present application and its preparation method and application are described in detail below in combination with examples.

[0087] The reagents used in the following examples are commercially available.

[0088] Example 1

[0089] The present application provides a tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst, and the loading amount of ruthenium is 1 wt%, and its synthesis method is as follows:

[0090] 2.28 g P123 was added to 155 mL of anhydrous ethanol, 730 μL of glacial acetic acid, 2.31 mL of hydrochloric acid, and 9 mL of zirconium n-propyl alcohol were added, and the stirring time was 30 minutes. The obtained sol was transferred to a 50 degree Celsius oven for gelation for 3 days. The obtained solid was calcined in a muffle furnace at 450 degrees Celsius for 6 hours to obtain tetragonal phase mesoporous zirconia.

[0091] 0.1062-0.3187 g of ammonium metatungstate was dissolved in 20 mL of deionized water, 1 g of zirconia was added, and the solvent was evaporated by vigorous stirring in a water bath. The obtained solid was calcined in a muffle furnace at 450 degrees Celsius for 6 hours to obtain tungsten oxide / mesoporous zirconia, and by changing the amount of ammonium metatungstate added, WO3 / ZrO2 with 10 wt%, 15 wt%, 20 wt%, 25 wt%, and 30 wt% of tungsten oxide on mesoporous zirconia was prepared.

[0092] 27 mg of ruthenium chloride hydrate was dissolved in 10 mL of deionized water, 1 g of tungsten oxide / mesoporous zirconia was added, and the solvent was evaporated by vigorous stirring in a water bath. The obtained sample was packed into a quartz reaction tube, reduced at 400 degrees Celsius for 2 hours, and the hydrogen flow rate was 50 mL / min to obtain a tungsten oxide / mesoporous zirconia supported ruthenium-based catalyst.

[0093] The tetragonal phase mesoporous zirconia obtained in Example 1 was analyzed by X-ray diffraction, and the X-ray diffraction pattern thereof is shown in Figure 1

[0094] ​The mesoporous zirconia obtained in Example 1 was analyzed by using a specific surface area tester, and the N2sorption-desorption spectrum thereof is shown in Figure 2 ; and the pore size distribution thereof is shown in Figure 3 .

[0095] The 25 wt% tungsten oxide / zirconia-supported ruthenium-based catalyst obtained in Example 1 was analyzed by using a transmission electron microscope, and the transmission electron micrograph thereof is shown in Figure 4 .

[0096] Example 2

[0097] Thermocatalytic high-density polyethylene degradation performance test of the tungsten oxide / zirconia-supported ruthenium-based catalyst:

[0098] After 200 mg of the 25 wt% tungsten oxide / zirconia-supported ruthenium-based catalyst powder obtained in Example 1 and 2.0 g of high-density polyethylene plastic particles (0.952 g / mL at 25°C, melt index 12 g / 10 min) were uniformly mixed, they were placed in a Hastelloy slurry bed reactor with a volume of 50 mL, the reactor was washed 10 times with 3 vol% N2 / H2, and 3 MPa 3 vol% N2 / H2was filled in the reactor, and the reaction was carried out at 250°C for 6 hours. Immediately after the reaction was completed, the reactor was placed in cold water for cooling for more than 1 hour, and then the gaseous products were detected by GC, and the results are shown in Figure 5 ; and it can be judged from Figure 5 whether the catalyst conforms to the metal-acid bifunctional catalytic mechanism. Then, 5 mL of cyclohexane was added as an internal standard and uniformly mixed with the liquid products, and after centrifugation, the supernatant and the precipitate were collected, the centrifugal speed was 13000 rpm, and the centrifugal time was 5 minutes, the supernatant was quantitatively determined by GC and qualitatively determined by GC-MS, the carbon number distribution of the liquid products is shown in Figure 5 , and the liquid yield and isomer product ratio are shown in Table 1. The precipitate obtained by centrifugation was dried in an oven at 80°C overnight to obtain a solid residue, and the mass of the solid residue was weighed by an analytical balance, and the mass of the remaining undegraded plastic was obtained by subtracting the mass of the catalyst added before the reaction, so that the solid conversion rate can be calculated, and the results are shown in Table 1.

[0099] Example 3

[0100] Comparison of high-density polyethylene degradation performance tests of tungsten oxide / zirconia-supported ruthenium-based catalysts under different H2partial pressures:

[0101] The Ru / WO3 / ZrO2 catalyst with 25 wt% of tungsten oxide prepared in Example 1 was used, and the reaction conditions in Example 2 were changed only by changing the partial pressure of 3 vol% N2 / H2 to 1 MPa, 2 MPa, and 4 MPa, respectively, to obtain the conversion rates under different H2 partial pressures as shown in Table 2. Figure 6

[0102] Example 4

[0103] C5-C12 isomerate yield, isoparaffin ratio, and conversion rate of the thermocatalytic high-density polyethylene degradation product of the tungsten oxide / zirconia-supported ruthenium-based catalyst 18 Test of the trends of fuel oil yield, isoparaffin ratio, and conversion rate with reaction time

[0104] The Ru / WO3 / ZrO2 catalyst with 25 wt% of tungsten oxide prepared in Example 1 was used, and the reaction conditions in Example 2 were changed only by changing the reaction time to 2 hours, 4 hours, 6 hours, and 8 hours, respectively, to obtain the catalytic performance. The time evolution test results of the thermocatalytic high-density polyethylene degradation of the tungsten oxide / zirconia-supported ruthenium-based catalyst are shown in Table 3. Figure 7

[0105] Example 5

[0106] Comparison of the thermocatalytic high-density polyethylene degradation performance of the tungsten oxide / zirconia-supported ruthenium-based catalysts with different tungsten oxide ratios. The Ru / WO3 / ZrO2 catalysts with 10 wt%, 15 wt%, 20 wt%, 25 wt%, and 30 wt% of tungsten oxide were prepared by changing the amount of ammonium metatungstate precursor added according to the method in Example 1, and the thermocatalytic high-density polyethylene degradation experiments were performed according to the reaction conditions in Example 2. The solid conversion rate, liquid phase yield, and isoparaffin ratio are shown in Table 1.

[0107] Example 6

[0108] The Ru / WO3 / ZrO2 catalyst with 15 wt% of tungsten oxide was prepared according to the method in Example 1 by adding 0.1594 g of ammonium metatungstate, and the thermocatalytic high-density polyethylene degradation experiment was performed according to the reaction conditions in Example 2. The liquid phase carbon number distribution results are shown in Table 2. Figure 8 Figure 8 It can be seen that when the WO3 ratio is 15 wt%, the product is mainly n-alkanes.

[0109] Comparative Example 1

[0110] ​​​According to the method described in Example 1, the amount of ammonium metatungstate added is 0.0531 g, and the remaining steps are unchanged, to prepare a Ru / WO3 / ZrO2 catalyst with a tungsten oxide proportion of 5 wt%, and to perform a thermal catalytic high-density polyethylene degradation experiment according to the reaction conditions in Example 2. The solid conversion rate, liquid phase yield, and isomer product ratio are shown in Table 1.

[0111] Comparative Example 2

[0112] According to the method described in Example 1, the amount of ammonium metatungstate added is 0.4251 g, and the remaining steps are unchanged, to prepare a Ru / WO3 / ZrO2 catalyst with a tungsten oxide proportion of 40 wt%, and to perform a thermal catalytic high-density polyethylene degradation experiment according to the reaction conditions in Example 2. The solid conversion rate, liquid phase yield, and isomer product ratio are shown in Table 1.

[0113] Table 1 Thermal catalytic high-density polyethylene degradation performance results of catalysts with different tungsten oxide contents

[0114]

[0115] In combination with Table 1, Figure 5 , Figure 8 It can be seen that only when the tungsten oxide content is less than 20 wt% does the metal Ru-dominated hydrogenolysis mechanism show, the product distribution is wide and mainly normal alkanes; when the tungsten oxide content is ≥20 wt%, the metal-acid bifunctional synergistic catalytic hydrogen cracking mechanism is shown, high-value isomerized alkane products are obtained, and the performance is best when the tungsten oxide content is 25 wt%.

[0116] The above only describes preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide, characterized in that, Includes a support and metallic ruthenium loaded on the support; the support includes mesoporous zirconium oxide and tungsten oxide; The mass of the tungsten oxide is 10% to 50% of the mass of the mesoporous zirconium oxide.

2. The ruthenium-based catalyst according to claim 1, characterized in that, The carrier comprises tetragonal mesoporous zirconium oxide and tungsten oxide.

3. The ruthenium-based catalyst according to claim 1, characterized in that, The mass of the tungsten oxide is 20% to 40% of the mass of the mesoporous zirconium oxide.

4. The ruthenium-based catalyst according to claim 1, characterized in that, The ruthenium-based catalyst has a ruthenium loading of 0.1% to 10%.

5. The ruthenium-based catalyst according to claim 1, characterized in that, The ruthenium loading in the ruthenium-based catalyst is 1%.

6. A method for preparing the ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide as described in claim 1, characterized in that, Includes the following steps: S1) Mesoporous zirconium oxide is mixed with a tungsten source in a first solvent, the solvent is removed, and then calcined to obtain a support; S2) The support and ruthenium source are mixed in a second solvent. After the solvent is removed, the mixture is heated in a reducing atmosphere to perform a reduction treatment, thereby obtaining a ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide.

7. The preparation method according to claim 6, characterized in that, The tungsten source is selected from one or more of ammonium metatungstate, sodium tungstate, and ammonium paratungstate. And / or, the ruthenium source is selected from one or more of ruthenium chloride, ruthenium nitrite, and ruthenium acetylacetone; And / or, the first solvent and the second solvent are each independently selected from water; And / or, the mesoporous zirconium oxide is prepared according to the following method: A1) A sol is obtained by mixing a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide, an alcohol solvent, an organic acid, an inorganic acid and a zirconium source. A2) The sol is heated to gel, yielding a solid; A3) The solid is calcined to obtain mesoporous zirconium oxide.

8. The preparation method according to claim 7, characterized in that, The polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer is shown in formula (I): Formula (I); Where x, y, and z are all degrees of aggregation, x is 10~30, y is 60~80, and z is 10~30; The zirconium source is selected from one or more of zirconium n-propoxide, zirconium acetate, zirconium acetylacetonate, and zirconium isopropoxide; And / or, the mass ratio of the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer to the zirconium source is (1~5):9; And / or, the mixing time in step A1) is 10~60 min; And / or, in step A2), the gelation temperature is 40℃~60℃; the gelation time is 2~4 days; And / or, the calcination temperature in step A3) is 400℃~600℃; the calcination time is 4~8 h.

9. The preparation method according to claim 6, characterized in that, The calcination temperature in step S1) is 400℃~600℃; the calcination time is 4~8 h. And / or, in step S2), the reducing atmosphere is hydrogen; the flow rate of the reducing atmosphere is 10~100 mL / min; the temperature of the reduction treatment is 300℃~500℃; and the time of the reduction treatment is 1~3 h.

10. The application of the ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide according to any one of claims 1 to 5 or the ruthenium-based catalyst supported on tungsten oxide / mesoporous zirconium oxide prepared by the preparation method according to any one of claims 6 to 9 in the thermocatalytic degradation of polyethylene.

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