Method for preparing liquid alkane by catalytically degrading waste mixed plastic

Abstract

The invention discloses a method for preparing liquid alkane by catalytically degrading waste mixed plastics, which comprises the following steps: reacting the waste mixed plastics consisting of polyolefin plastics and oxygen-containing plastics with hydrogen under the action of a catalyst at 150-350 DEG C under a solvent-free condition; separating a reaction product to obtain liquid alkane; the catalyst comprises a carrier and an active component loaded on the carrier, wherein the active component is at least one of Ru, Re, Pt, Pd, Ni, Co, Mo and Cr; the carrier is at least one of activated carbon, a metal oxide and a molecular sieve.

Description

A method for preparing liquid alkanes by catalytic degradation of waste mixed plastics Technical Field

[0001] This invention relates to energy and chemical engineering, and more specifically to a method for preparing liquid alkanes by catalytic degradation of waste mixed plastics. Background Technology

[0002] Plastics are important raw materials for organic synthetic polymers and have become an indispensable part of modern life. However, due to their generally poor biodegradability, plastic waste has become a major global environmental challenge in the 21st century. The degradation of plastics is essentially a process of breaking the bonds within the polymer. In common plastics, those linked by C-C and CO bonds account for over 80%, such as PET, PP, PE, PC, PS, and PPO, and they often exist in mixed forms. For example, mixtures of PE and PET are widely used in packaging materials, mixtures of PET and PC are used in medical devices, and mixtures of PPO and PS are commonly found in household appliances. Therefore, developing technologies suitable for the degradation of mixed plastics is of great significance.

[0003] Given the complex and diverse structures of mixed plastics, the products obtained from catalytic degradation are inevitably complex mixtures, posing significant challenges to subsequent separation processes and significantly increasing costs. While pyrolysis technology can directly process mixed plastics, it typically requires temperatures above 500°C (CN106947509A, CN103484142A, CN118103486A, CN105733639A, CN121136732A, US2020017773, US2020017772), resulting in enormous energy consumption and complex products. Alcohololysis and acidolysis are only useful for plastics with partially CO2-bonded structures, limiting the types of substrates available for practical plastic degradation applications. Furthermore, the catalytic process requires the use of environmentally unfriendly liquid acids such as sulfuric acid and hydrochloric acid as catalysts, and the separation of alcohols or acids from the products presents significant challenges (CN107189114A). Developing a degradation technology that can directly convert these mixed plastics without additional separation steps would offer significant economic and environmental benefits for resource utilization. The liquid hydrocarbon products can be directly used to produce transportation fuels such as gasoline, diesel, and jet fuel. Therefore, from both the perspective of raw material resource utilization and product application, converting mixed plastics into liquid hydrocarbon products through hydrogenolysis by simultaneously breaking CC / CO bonds is clearly one of the most promising technologies in the field of waste plastic degradation. However, most current research is still limited to the conversion of single plastics. Because mixed plastics contain multiple different polymers, the diversity and stability of their bonding structures make their degradation process more complex and challenging than that of single plastics. Currently, no catalyst can achieve this challenging goal. Therefore, a new degradation technology is urgently needed to simultaneously break CC / CO bonds and efficiently and directly convert mixed plastics into liquid hydrocarbon products. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a method for preparing liquid alkanes by catalytic degradation of waste mixed plastics, thereby solving the problems of low efficiency and complex products in existing mixed plastic recycling methods.

[0005] Technical solution: The method for preparing liquid alkanes by catalytic degradation of waste mixed plastics according to the present invention includes reacting waste mixed plastics composed of polyolefin plastics and oxygen-containing plastics with hydrogen under solvent-free conditions at 150-350°C in the presence of a catalyst; separating the reaction products to obtain liquid alkanes.

[0006] Preferably, a mixed plastic composed of polyolefins and oxygen-containing plastics is directly converted into fuel under mild, solvent-free conditions after crushing. The mixed plastics do not require pre-separation processes, and the resulting product can be used directly as fuel without further separation. Furthermore, since the plastic melts at high temperatures, the degree of substrate crushing has little impact on the reaction; crushing to a level suitable for loading is sufficient. Using a metal / solid acid as a bifunctional catalyst and hydrogen as the hydrogen source, the reaction is carried out at 150-350℃ for a certain time. The catalyst and reaction products are separated, and the catalyst is recycled.

[0007] The direct conversion of mixed plastics, consisting of polyolefins and oxygen-containing plastics, to produce fuels places extremely high demands on the catalyst's active components' resistance to poisoning by oxygen-containing intermediates. Furthermore, a suitable catalyst is needed to simultaneously and efficiently break both C-C and CO bonds to achieve high yields of liquid alkane products. Conventional catalysts, when directly converting mixed plastics, are easily poisoned by the polar functional groups of the oxygen-containing plastics and oxygen-containing intermediates (such as cyclic alcohol intermediates) generated during degradation, making it difficult to simultaneously possess sufficient CO and C-C bond breaking activity. Therefore, high-efficiency direct conversion of mixed plastics, consisting of polyolefins and oxygen-containing plastics, to produce fuels places extremely high demands on the catalyst.

[0008] The catalyst includes a support and an active component supported on the support, wherein the active component is at least one of Ru, Re, Pt, Pd, Ni, Co, Mo, and Cr.

[0009] The carrier is at least one of activated carbon, metal oxide, and molecular sieve. The metal oxide is at least one of Al2O3, TiO2, ZrO2, CeO2, MgO2, and SiO2. The molecular sieve is at least one of H-ZSM-5 and HY zeolite.

[0010] Preferably, the oxygen-containing plastic in the waste mixed plastic is at least one of polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polycarbonate.

[0011] Preferably, the polyolefin plastic in the waste mixed plastic is at least one of high-density linear polyethylene, low-density linear polyethylene, and polypropylene.

[0012] Preferably, the mass ratio of polyolefin plastic to oxygen-containing plastic in the waste mixed plastic is 4~20:1.

[0013] Preferably, the mass ratio of the waste mixed plastic to the catalyst is 10~100:1.

[0014] Preferably, the mass ratio of the carrier to the active ingredient is 40~200:1.

[0015] Preferably, the active ingredient is a bimetallic combination, consisting of Ru metal and one of Pt, Pd, Re, Ni, Co, Mo, or Cr metals, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, or HY.

[0016] Preferably, the hydrogen pressure is 0.5~10 MPa.

[0017] Preferably, the reaction time is 1 to 50 hours.

[0018] Preferably, the main components of the liquid alkane product are C7~C6. 17 Straight-chain alkanes, branched alkanes, and / or cycloalkanes.

[0019] Preferably, the oxygen-containing plastic polymer in the mixed plastic is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, and polycarbonate; the polyolefin plastic polymer in the mixed plastic is selected from at least one of high-density linear polyethylene and low-density linear polyethylene.

[0020] Preferably, the oxygen-containing plastic polymer in the mixed plastic is selected from at least one of polyethylene terephthalate and polycarbonate; the polyolefin plastic polymer in the mixed plastic is selected from at least one of high-density linear polyethylene and low-density linear polyethylene.

[0021] Preferably, the oxygen-containing plastic polymer in the mixed plastic is selected from at least one of polyethylene terephthalate and polycarbonate; the polyolefin plastic polymer in the mixed plastic is low-density linear polyethylene.

[0022] Preferably, the oxygen-containing plastic polymer in the mixed plastic is polyethylene terephthalate; and the polyolefin plastic polymer in the mixed plastic is low-density linear polyethylene.

[0023] Preferably, the active metal component in the catalyst is composed of at least one of Ru, Pt, Pd, and Re metals, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0024] Preferably, the bimetallic active component in the catalyst is composed of at least one of Ru metal and Pt, Pd, or Re metal, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, or HY.

[0025] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Re metal, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0026] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Re metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0027] Preferably, the bimetallic active component in the catalyst consists of Ru metal and Re metal, and the support component is CeO2.

[0028] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Pt metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0029] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Pt metal, and the support component is CeO2.

[0030] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Pd metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0031] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Pd metal, and the support component is CeO2.

[0032] Preferably, the active metal component in the catalyst is Ni, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0033] Preferably, the active metal component in the catalyst is Co, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0034] Preferably, the active metal component in the catalyst is Mo, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0035] Preferably, the active metal component in the catalyst is Cr, and the support component is at least one of activated carbon, Al2O3, TiO2, ZrO2, CeO2, MgO2, SiO2, H-ZSM-5, and HY.

[0036] Preferably, the active metal component in the catalyst is Ni, and the support component is CeO2.

[0037] Preferably, the active metal component in the catalyst is Co, and the support component is CeO2.

[0038] Preferably, the active metal component in the catalyst is Mo, and the support component is CeO2.

[0039] Preferably, the active metal component in the catalyst is Cr, and the support component is CeO2.

[0040] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Ni metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0041] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Ni metal, and the support component is CeO2.

[0042] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Co metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0043] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Co metal, and the support component is CeO2.

[0044] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Mo metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0045] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Mo metal, and the support component is CeO2.

[0046] Preferably, the bimetallic active component in the catalyst is composed of Ru metal and Cr metal, and the support component is at least one of TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

[0047] Preferably, the bimetallic active component in the catalyst consists of Ru metal and Cr metal, and the support component is CeO2.

[0048] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: 1. The core of this invention is to use waste mixed plastics that are difficult to biodegrade naturally as raw materials, achieving efficient breaking of C–C and C–O bonds simultaneously during the degradation process of the mixed plastics, directly converting the mixed plastics composed of polyolefins and oxygen-containing plastics into fuel. Starting from the mixed plastics, the carbon yield of liquid alkanes is 20.0-88.7%, with the highest alkane yield reaching 88.7% and the highest alkane product yield reaching 98.6%, demonstrating good industrial value.

[0049] 2. This invention utilizes the synergistic effect of metal species in the catalyst and the support, enabling the metal sites (Ru species) to efficiently break down C-C bonds and Lewis acids (ReO2). x The CeO2 support possesses a unique long-distance hydrogen spillover capability, enabling highly selective activation of CO bonds. This allows the active hydrogen species dissociated at Ru sites to overflow onto ReOx, completing the hydrogenolysis of oxygen-containing plastics and their intermediates. Through the synergistic effect of the metal sites, Lewis acid, and the support, CO and C bonds in mixed plastics are efficiently and directly broken, yielding directly usable liquid alkane products without the need for pre-separation steps.

[0050] 3. The reaction temperature is 150-350℃, which is much lower than the high temperature of over 500℃ required by traditional pyrolysis, resulting in low energy consumption. The system uses a solvent-free approach, with only hydrogen as the reaction medium and hydrogen source. After the reaction, the product can be obtained simply by separating the catalyst. The process is simple and environmentally friendly. The catalyst can be regenerated by simple calcination after the reaction and recycled, reducing costs. Attached Figure Description

[0051] Figure 1 is a schematic diagram of the process for preparing liquid alkanes according to the present invention.

[0052] Figure 2 is a schematic diagram showing the conversion of different types of plastics into liquid alkane products using the method of this invention.

[0053] Figure 3 is a schematic diagram comparing the method of the present invention with the traditional multi-step degradation strategy for mixed plastics. Detailed Implementation

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] Referring to Figure 1, a method for preparing liquid alkane fuel by catalytic degradation of waste mixed plastics includes: S100, reacting a mixed plastic consisting of polyolefins and oxygen-containing plastics with hydrogen in a reactor at a temperature below 350°C under the action of a catalyst; S200, centrifuging to separate the reaction products to obtain liquid alkane products and a reusable catalyst.

[0056] In one embodiment, prior to step S100, the process further includes: crushing the mixed plastic consisting of polyolefin and oxygen-containing plastic.

[0057] In the above method, the mixed plastic composed of polyolefin and oxygen-containing plastic can be a mixture of a single type or a single plastic product composed of multiple plastics. For a mixture of multiple types of polymers, the mass ratio of polyolefin to oxygen-containing plastic in the mixed plastic can be 4:1, 5:1, 10:1, or 20:1. Under the same reaction conditions, the mixed plastic composed of polyolefin and oxygen-containing plastic can be efficiently converted into fuel.

[0058] The mixed plastic is composed of a polyolefin and an oxygen-containing plastic. The polyolefin plastic is selected from at least one of high-density linear polyethylene, low-density linear polyethylene, and polypropylene. The oxygen-containing plastic is selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polycarbonate. Preferably, the polymer of the polyolefin plastic is at least one of high-density linear polyethylene and low-density linear polyethylene, and the polymer of the oxygen-containing plastic is at least one of polyethylene terephthalate, polyphenylene ether, and polycarbonate. Further, the polyolefin and the oxygen-containing plastic in the mixed plastic are selected from polycarbonate and polyethylene, respectively.

[0059] For crushing mixed plastics, the process should be such that the material is easy to load, for example, the particle size can be 10 mm.

[0060] In step S100, the mass ratio of the mixed plastic to the catalyst is 10~100:1, the reaction temperature is 150~350℃, the hydrogen pressure is 0.5~10 MPa, and the reaction time is 1~50 h. The catalyst comprises a support and an active component supported on the support. The active component is selected from at least one of Ru, Re, Pt, Pd, Ni, Co, Ti, Mo, and Cr. The support is selected from at least one of activated carbon, metal oxides, and molecular sieves. The metal oxide is selected from at least one of Al2O3, TiO2, ZrO2, CeO2, MgO2, and SiO2. The molecular sieve is selected from at least one of H-ZSM-5 and HY zeolite.

[0061] The catalyst includes a support and an active component supported on the support, wherein the active component is selected from at least one of Ru, Re, Pt, Pd, Ni, Co, Ti, Mo and Cr.

[0062] The support is selected from at least one of activated carbon, metal oxide, or molecular sieve. The metal oxide in the support is selected from at least one of Al2O3, TiO2, ZrO2, CeO2, MgO2, and SiO2, and the molecular sieve is selected from at least one of H-ZSM-5 and HY zeolite.

[0063] Preferably, the active ingredient is at least one of Ru and Re, and the support is selected from at least one of activated carbon, molecular sieve, zirconium oxide, cerium oxide, and titanium oxide, for example, selected from at least one of H-ZSM-5, ZrO2, CeO2, and TiO2.

[0064] Furthermore, the active component in the catalyst is at least one of Ru and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0065] Furthermore, the active component in the catalyst is a bimetallic component of Ru and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0066] Furthermore, the active component in the catalyst is a bimetallic component of Ru and Re, and the support is selected from at least one of ZrO2 and CeO2.

[0067] Furthermore, the active component in the catalyst is a bimetallic component of Ru and Re, and the support is CeO2.

[0068] Furthermore, the mass ratio of the support to the Ru metal active component in the catalyst is 100:3, and the mass ratio of the support to the Re metal active component is 200:1.5.

[0069] Preferably, the active ingredient is at least one of Pt and Re, and the support is selected from at least one of molecular sieves, zirconium oxides, cerium oxides, and titanium oxides, for example, selected from at least one of H-ZSM-5, ZrO2, CeO2, and TiO2.

[0070] Furthermore, the active component in the catalyst is at least one of Pt and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0071] Furthermore, the active component in the catalyst is a bimetallic component of Pt and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0072] Furthermore, the active component in the catalyst is a bimetallic component of Pt and Re, and the support is selected from at least one of ZrO2 and CeO2.

[0073] Furthermore, the active component in the catalyst is a bimetallic component of Pt and Re, and the support is CeO2.

[0074] Preferably, the active ingredient is at least one of Pd and Re, and the support is selected from at least one of molecular sieves, zirconium oxides, cerium oxides, and titanium oxides, for example, from at least one of H-ZSM-5, ZrO2, CeO2, and TiO2.

[0075] Furthermore, the active component in the catalyst is at least one of Pd and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0076] Furthermore, the active component in the catalyst is a Pd and Re bimetallic component, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0077] Furthermore, the active component in the catalyst is a bimetallic component of Pd and Re, and the support is selected from at least one of ZrO2 and CeO2.

[0078] Furthermore, the active component in the catalyst is a bimetallic component of Pd and Re, and the support is CeO2.

[0079] Preferably, the active ingredient is at least one of Ni and Re, and the support is selected from at least one of molecular sieves, zirconium oxides, cerium oxides, and titanium oxides, for example, selected from at least one of H-ZSM-5, ZrO2, CeO2, and TiO2.

[0080] Furthermore, the active component in the catalyst is at least one of Ni and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0081] Furthermore, the active component in the catalyst is a bimetallic component of Ni and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0082] Furthermore, the active component in the catalyst is a bimetallic component of Ni and Re, and the support is selected from at least one of ZrO2 and CeO2.

[0083] Furthermore, the active component in the catalyst is a bimetallic component of Ni and Re, and the support is CeO2.

[0084] Preferably, the active ingredient is at least one of Co and Re, and the support is selected from at least one of activated carbon, molecular sieve, zirconium oxide, cerium oxide, and titanium oxide, for example, selected from at least one of H-ZSM-5, ZrO2, CeO2, and TiO2.

[0085] Furthermore, the active component in the catalyst is at least one of Co and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0086] Furthermore, the active component in the catalyst is a bimetallic component of Co and Re, and the support is selected from at least one of H-ZSM-5, ZrO2, and CeO2.

[0087] Furthermore, the active component in the catalyst is a bimetallic component of Co and Re, and the support is selected from at least one of ZrO2 and CeO2.

[0088] Furthermore, the active component in the catalyst is a bimetallic component of Co and Re, and the support is CeO2.

[0089] In step S200, the reaction product is centrifuged to separate the precipitate into a catalyst and the supernatant into a liquid alkane product. The resulting catalyst can be calcined, for example at 400°C, to remove coke / carbon deposits from its surface, enabling catalyst regeneration, extending its lifespan, reducing costs, and improving efficiency.

[0090] As shown in Figure 2, liquid alkane products can be prepared for both single types of polyolefin polymers and mixtures of polyolefins and various oxygen-containing plastics.

[0091] The method of this invention enables the catalytic hydrogenation degradation of polyethylene to produce liquid alkanes, specifically C7-C... 16 The main products are straight-chain alkanes.

[0092] The method of this invention enables the catalytic hydrogenation degradation of polypropylene to prepare liquid alkanes, wherein C8-C... 17 Branched alkanes are the main products.

[0093] The method of this invention enables the catalytic hydrogenation degradation of mixed plastics composed of polyethylene and polyethylene terephthalate (PET) to produce liquid alkanes, wherein the C7-C... 16 The main products are straight-chain alkanes and cycloalkanes.

[0094] The method of this invention enables the catalytic hydrogenation degradation of mixed plastics composed of polyethylene and polycarbonate (PC) to produce liquid alkanes, wherein C7-C... 16 The main products are straight-chain alkanes and cycloalkanes.

[0095] The method of this invention enables the catalytic hydrogenation degradation of mixed plastics composed of polyethylene and polybutylene terephthalate (PBT) to produce liquid alkanes, wherein the C7-C... 16 The main products are straight-chain alkanes and cycloalkanes.

[0096] The method of this invention enables the catalytic hydrogenation degradation of mixed plastics composed of polyethylene and polyphenylene ether (PPO) to produce liquid alkanes, wherein C7-C... 16 The main products are straight-chain alkanes and cycloalkanes.

[0097] This invention utilizes a widely distributed and inexpensive mixture of polyolefins and oxygen-containing plastics as raw materials. Through the catalytic action of a catalyst, the CO and C-C bonds are broken simultaneously and directly, converting the mixed plastics composed of polyolefins and oxygen-containing plastics into fuel. This catalytic system can directly and efficiently convert mixed plastics into liquid alkanes, yielding important bulk fuels. More importantly, this method can also directly and efficiently convert real mixed plastics into fuels that require no further treatment, such as packaging materials composed of PE and PET. This is of great significance for the direct catalytic conversion of mixed waste plastics into fuels, greatly saving energy, reducing environmental pollution, and facilitating industrial application.

[0098] Example 1

[0099] Experimental Materials: Oxygen-containing plastic polymer: 0.25 g polyethylene terephthalate; Polyolefin plastic: 1 g low-density polyethylene; Solvent: Solvent-free; Mass ratio of polyolefin plastic to oxygen-containing plastic polymer: 4; Catalyst: Active components are Ru and Re, support is CeO2, the mass ratio of support to Ru metal active component in the catalyst is 100:3, the mass ratio of support to Re metal active component is 200:1.5, catalyst mass is 0.1 g; Experimental Conditions: Hydrogen pressure: 3 MPa; Reaction temperature: 250 ℃; Reaction time: 12 h; Experimental Method: The mixture of 1.0 g low-density polyethylene and 0.25 g polyethylene terephthalate was crushed to about 10 mm in a pulverizer, and the crushed mixture of low-density polyethylene and polyethylene terephthalate and 0.1 g... RuRe / CeO2 was added to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, sealed, and charged with 3 MPa of hydrogen. The reactor was heated to the required temperature of 250 °C under rapid stirring and the reaction was stopped after 12 hours. The reactor was cooled, the catalyst was separated by centrifugation, and the upper liquid alkane product was collected. The molar yield of the liquid alkane was 84%.

[0100] Example 2: The only difference from Example 1 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0101] Example 3: The only difference from Example 1 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0102] Example 4: The only difference from Example 1 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0103] Example 5: The only difference from Example 1 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0104] Example 6: The only difference from Example 1 is that the active component in the catalyst is Ru metal active sites.

[0105] Example 7: The only difference from Example 1 is that the active component in the catalyst is Re metal active sites.

[0106] Example 8: The only difference from Example 1 is that the active component in the catalyst is Pt metal active sites.

[0107] Example 9: The only difference from Example 1 is that the active component in the catalyst is Pd metal active sites.

[0108] Example 10: The only difference from Example 1 is that the active component in the catalyst is Ni metal active sites.

[0109] Example 11: The only difference from Example 1 is that the active component in the catalyst is Co metal active sites.

[0110] Example 12: The only difference from Example 1 is that the catalyst support is Al2O3.

[0111] Example 13: The only difference from Example 1 is that the catalyst support is TiO2.

[0112] Example 14: The only difference from Example 1 is that the catalyst support is ZrO2.

[0113] Example 15: The only difference from Example 1 is that the catalyst support is MgO2.

[0114] Example 16: The only difference from Example 1 is that the catalyst support is SiO2.

[0115] Example 17: The only difference from Example 1 is that the catalyst support is H-ZSM-5.

[0116] Example 18: The only difference from Example 1 is that the catalyst support is HY.

[0117] Example 19: The only difference from Example 1 is that only polyolefin polymers are used as reaction substrates: 1.0 g of low-density polyethylene.

[0118] Example 20: The only difference from Example 19 is that the polyolefin plastic polymer is 1.0g of high-density polyethylene.

[0119] Example 21: The only difference from Example 19 is that the polyolefin plastic polymer is 1.0 g of polypropylene.

[0120] Example 22: The only difference from Example 1 is that the polymer mass of polyethylene terephthalate is 0.2g; the mass ratio of polyolefin plastics to oxygen-containing plastics is 5.

[0121] Example 23: The only difference from Example 1 is that the polymer mass of polyethylene terephthalate is 0.1g; the mass ratio of polyolefin plastics to oxygen-containing plastics is 10.

[0122] Example 24: The only difference from Example 1 is that the polymer mass of polyethylene terephthalate is 0.05g; the mass ratio of polyolefin plastics to oxygen-containing plastics is 20.

[0123] Example 25: The only difference from Example 1 is that the oxygen-containing plastic polymer: 0.25 g of polycarbonate.

[0124] Example 26: The only difference from Example 1 is that the oxygen-containing plastic polymer is polybutylene terephthalate 0.25 g.

[0125] Example 27: The only difference from Example 1 is that the oxygen-containing plastic polymer: polyphenylene ether 0.25 g.

[0126] Example 28: The only difference from Example 1 is that the polyolefin plastic polymer is 1.0g of high-density polyethylene.

[0127] Example 29: The only difference from Example 28 is that the oxygen-containing plastic polymer: 0.25 g of polycarbonate.

[0128] Example 30: The only difference from Example 28 is that the oxygen-containing plastic polymer is polybutylene terephthalate 0.25 g.

[0129] Example 31: The only difference from Example 28 is that the oxygen-containing plastic polymer: polyphenylene ether 0.25 g.

[0130] Example 32: The only difference from Example 21 is that the oxygen-containing plastic polymer: 0.25 g of mineral water bottle; and the polyolefin plastic polymer: 1.0 g of plastic dropper.

[0131] Example 33: The only difference from Example 32 is that the oxygen-containing plastic polymer: 0.25 g of polycarbonate sheet.

[0132] Example 34: The only difference from Example 32 is that the oxygen-containing plastic polymer: 0.25 g of polybutylene terephthalate sheet; and the polyolefin plastic polymer: 1.0 g of cling film.

[0133] Example 35: The only difference from Example 32 is that the oxygen-containing plastic polymer: 0.25 g of polyphenylene ether particles.

[0134] Example 36: The only difference from Example 32 is that the oxygen-containing plastic polymer: 0.25 g of mineral water bottle; the polyolefin plastic polymer: 1.0 g of mineral water bottle cap; and the reaction time: 20 h.

[0135] Example 37: The only difference from Example 36 is that the oxygen-containing plastic polymer: 0.25 g of polycarbonate sheet; the polyolefin plastic polymer: 1.0 g of mineral water bottle cap; the reaction time: 12 h; and the reaction temperature: 270 °C.

[0136] Example 38: The only difference from Example 37 is that the polyolefin plastic polymer is: 1.0g of white milk bag.

[0137] Example 39: The only difference from Example 37 is that the polyolefin plastic polymer is 1.0g of polypropylene plastic bag.

[0138] Example 40: The only difference from Example 39 is that the oxygen-containing plastic polymer: 0.25 g of polybutylene terephthalate sheet.

[0139] Example 41: The only difference from Example 12 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0140] Example 42: The only difference from Example 12 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0141] Example 43: The only difference from Example 12 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0142] Example 44: The only difference from Example 12 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0143] Example 45: The only difference from Example 13 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0144] Example 46: The only difference from Example 13 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0145] Example 47: The only difference from Example 13 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0146] Example 48: The only difference from Example 13 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0147] Example 49: The only difference from Example 14 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0148] Example 50: The only difference from Example 14 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0149] Example 51: The only difference from Example 14 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0150] Example 52: The only difference from Example 14 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0151] Example 53: The only difference from Example 15 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0152] Example 54: The only difference from Example 15 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0153] Example 55: The only difference from Example 15 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0154] Example 56: The only difference from Example 15 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0155] Example 57: The only difference from Example 16 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0156] Example 58: The only difference from Example 16 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0157] Example 59: The only difference from Example 16 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0158] Example 60: The only difference from Example 16 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0159] Example 61: The only difference from Example 17 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0160] Example 62: The only difference from Example 17 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0161] Example 63: The only difference from Example 17 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0162] Example 64: The only difference from Example 17 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0163] Example 65: The only difference from Example 18 is that the active component in the catalyst is a Pt and Re bimetallic active component.

[0164] Example 66: The only difference from Example 18 is that the active component in the catalyst is a Pd and Re bimetallic active component.

[0165] Example 67: The only difference from Example 18 is that the active component in the catalyst is a Ni and Re bimetallic active component.

[0166] Example 68: The only difference from Example 18 is that the active component in the catalyst is a Co and Re bimetallic active component.

[0167] Example 69: The only difference from Example 1 is that the active component in the catalyst is a Ru / Pt bimetallic active component.

[0168] Example 70: The only difference from Example 1 is that the active component in the catalyst is a Ru and Pd bimetallic active component.

[0169] Example 71: The only difference from Example 1 is that the active component in the catalyst is a Ru and Ni bimetallic active component.

[0170] Example 72: The only difference from Example 1 is that the active component in the catalyst is a Ru and Co bimetallic active component.

[0171] Example 73: The only difference from Example 1 is that the active component in the catalyst is a Ru and Ti bimetallic active component.

[0172] Example 74: The only difference from Example 1 is that the active component in the catalyst is a Ru and Mo bimetallic active component.

[0173] Example 75: The only difference from Example 1 is that the active component in the catalyst is a Ru and Cr bimetallic active component.

[0174] Example 76: The only difference from Example 1 is that the oxygen-containing plastic in the mixed plastic is composed of 0.05 g of polyethylene terephthalate, 0.05 g of polycarbonate, 0.05 g of polybutylene terephthalate, and 0.05 g of polyphenylene ether; the polyolefin plastic in the mixed plastic is composed of 0.4 g of low-density polyethylene, 0.4 g of high-density polyethylene, and 0.2 g of polypropylene.

[0175] Example 77: The only difference from Example 1 is that the reaction plastic substrate is 1.0 g of polyvinyl acetate.

[0176] Example 78: The only difference from Example 6 is that the catalyst support is activated carbon.

[0177] Example 79: The only difference from Example 7 is that the catalyst support is activated carbon.

[0178] Example 80: The only difference from Example 8 is that the catalyst support is activated carbon.

[0179] Example 81: The only difference from Example 9 is that the catalyst support is activated carbon.

[0180] Example 82: The only difference from Example 10 is that the catalyst support is activated carbon.

[0181] Example 83: The only difference from Example 11 is that the catalyst support is activated carbon.

[0182] Example 84: The only difference from Example 1 is that the catalyst support is activated carbon.

[0183] Example 85: The only difference from Example 69 is that the catalyst support is activated carbon.

[0184] Example 86: The only difference from Example 70 is that the catalyst support is activated carbon.

[0185] Example 87: The only difference from Example 71 is that the catalyst support is activated carbon.

[0186] Example 88: The only difference from Example 72 is that the catalyst support is activated carbon.

[0187] Example 89: The only difference from Example 73 is that the catalyst support is activated carbon.

[0188] Example 90: The only difference from Example 74 is that the catalyst support is activated carbon.

[0189] Example 91: The only difference from Example 75 is that the catalyst support is activated carbon.

[0190] Example 92: The only difference from Example 1 is that the catalytic reaction temperature is 150°C.

[0191] Example 93: The only difference from Example 1 is that the catalytic reaction temperature is 350°C.

[0192] Example 94: The only difference from Example 1 is that the catalytic reaction time is 1 h.

[0193] Example 95: The only difference from Example 1 is that the catalytic reaction time is 50 h.

[0194] Example 96: The only difference from Example 1 is that the mass ratio of the carrier to the Ru and Re bimetallic active components is 40:1.

[0195] Example 97: The only difference from Example 1 is that the mass ratio of the carrier to the Ru and Re bimetallic active components is 200:1.

[0196] Comparative Example 1: The only difference from Example 1 is that nitrogen is used instead of hydrogen.

[0197] Comparative Example 2: The only difference from Example 1 is that Al2O3 was used instead of RuRe / CeO2 as the catalyst.

[0198] Comparative Example 3: The only difference from Example 1 is that TiO2 was used instead of RuRe / CeO2 as the catalyst.

[0199] Comparative Example 4: The only difference from Example 1 is that MgO2 is used instead of RuRe / CeO2 as the catalyst.

[0200] Comparative Example 5: The only difference from Example 1 is that SiO2 was used instead of RuRe / CeO2 as the catalyst.

[0201] Comparative Example 6: The only difference from Example 1 is that CeO2 was used instead of RuRe / CeO2 as the catalyst.

[0202] Comparative Example 7: The only difference from Example 1 is that the catalyst used is H-ZSM-5 instead of RuRe / CeO2.

[0203] Comparative Example 8: The only difference from Example 1 is that HY was used instead of RuRe / CeO2 as the catalyst.

[0204] Comparative Example 9: The only difference from Example 19 is that Al2O3 was used instead of RuRe / CeO2 as the catalyst.

[0205] Comparative Example 10: The only difference from Example 19 is that TiO2 was used instead of RuRe / CeO2 as the catalyst.

[0206] Comparative Example 11: The only difference from Example 19 is that ZrO2 was used instead of RuRe / CeO2 as the catalyst.

[0207] Comparative Example 12: The only difference from Example 19 is that MgO2 is used instead of RuRe / CeO2 as the catalyst.

[0208] Comparative Example 13: The only difference from Example 19 is that SiO2 was used instead of RuRe / CeO2 as the catalyst.

[0209] Comparative Example 14: The only difference from Example 19 is that CeO2 was used instead of RuRe / CeO2 as the catalyst.

[0210] Comparative Example 15: The only difference from Example 19 is that the catalyst used is H-ZSM-5 instead of RuRe / CeO2.

[0211] Comparative Example 16: The only difference from Example 19 is that HY was used instead of RuRe / CeO2 as the catalyst.

[0212] Comparative Example 17: The only difference from Example 1 is that the active component in the catalyst is a Pt and Mo bimetallic active component.

[0213] Comparative Example 18: The only difference from Example 1 is that the active component in the catalyst is a Pd and Mo bimetallic active component.

[0214] Comparative Example 19: The only difference from Example 1 is that the active component in the catalyst is a Ni and Mo bimetallic active component.

[0215] Comparative Example 20: The only difference from Example 1 is that the active component in the catalyst is a Co and Mo bimetallic active component.

[0216] Comparative Example 21: The only difference from Example 1 is that the active component in the catalyst is a Pt / Ti bimetallic active component.

[0217] Comparative Example 22: The only difference from Example 1 is that the active component in the catalyst is a Pd and Ti bimetallic active component.

[0218] Comparative Example 23: The only difference from Example 1 is that the active component in the catalyst is a Ni / Ti bimetallic active component.

[0219] Comparative Example 24: The only difference from Example 1 is that the active component in the catalyst is a Co and Ti bimetallic active component.

[0220] Comparative Example 25: The only difference from Example 1 is that the active component in the catalyst is a Pt and Mn bimetallic active component.

[0221] Comparative Example 26: The only difference from Example 1 is that the active component in the catalyst is a Pd and Mn bimetallic active component.

[0222] Comparative Example 27: The only difference from Example 1 is that the active component in the catalyst is a Ni and Mn bimetallic active component.

[0223] Comparative Example 28: The only difference from Example 1 is that the active component in the catalyst is a Co and Mn bimetallic active component.

[0224] Comparative Example 29: The only difference from Example 1 is that the active component in the catalyst is a Pt and Cr bimetallic active component.

[0225] Comparative Example 30: The only difference from Example 1 is that the active component in the catalyst is a Pd and Cr bimetallic active component.

[0226] Comparative Example 31: The only difference from Example 1 is that the active component in the catalyst is a Ni and Cr bimetallic active component.

[0227] Comparative Example 32: The only difference from Example 1 is that the active component in the catalyst is a Co and Cr bimetallic active component.

[0228] Comparative Example 33: The only difference from Example 19 is that the catalyst support is Al2O3.

[0229] Comparative Example 34: The only difference from Example 19 is that the catalyst support is TiO2.

[0230] Comparative Example 35: The only difference from Example 19 is that the catalyst support is ZrO2.

[0231] Comparative Example 36: The only difference from Example 19 is that the catalyst support is MgO2.

[0232] Comparative Example 37: The only difference from Example 19 is that the catalyst support is SiO2.

[0233] Comparative Example 38: The only difference from Example 19 is that the catalyst support is H-ZSM-5.

[0234] Comparative Example 39: The only difference from Example 19 is that the catalyst support is HY.

[0235] Comparative Example 40: The only difference from Example 19 is that the catalyst support is Al2O3 and the active component in the catalyst is Pt metal active component.

[0236] Comparative Example 41: The only difference from Example 19 is that the catalyst support is TiO2 and the active component in the catalyst is Pt metal active component.

[0237] Comparative Example 42: The only difference from Example 19 is that the support in the catalyst is ZrO2 and the active component in the catalyst is Pt metal active component.

[0238] Comparative Example 43: The only difference from Example 19 is that the catalyst support is MgO2 and the active component in the catalyst is Pt metal active component.

[0239] Comparative Example 44: The only difference from Example 19 is that the catalyst support is SiO2 and the active component in the catalyst is Pt metal active component.

[0240] Comparative Example 45: The only difference from Example 19 is that the catalyst support is H-ZSM-5 and the active component in the catalyst is Pt metal active component.

[0241] Comparative Example 46: The only difference from Example 19 is that the support in the catalyst is HY and the active component in the catalyst is Pt metal active component.

[0242] Comparative Example 47: The only difference from Example 19 is that the catalyst support is TiO2 and the active component in the catalyst is a Ru and Pt bimetallic active component.

[0243] Comparative Example 48: The only difference from Example 19 is that the catalyst support is ZrO2 and the active component in the catalyst is a Ru-Pt bimetallic active component.

[0244] Comparative Example 49: The only difference from Example 19 is that the catalyst support is H-ZSM-5 and the active component in the catalyst is a Ru-Pt bimetallic active component.

[0245] Comparative Example 50: The only difference from Example 19 is that the catalyst support is HY and the active component in the catalyst is a Ru and Pt bimetallic active component.

[0246] Comparative Example 51: The only difference from Example 19 is that the catalyst support is TiO2 and the active component in the catalyst is a Ru and Pd bimetallic active component.

[0247] Comparative Example 52: The only difference from Example 19 is that the catalyst support is ZrO2 and the active component in the catalyst is a Ru and Pd bimetallic active component.

[0248] Comparative Example 53: The only difference from Example 19 is that the catalyst support is H-ZSM-5 and the active component in the catalyst is a Ru-Pd bimetallic active component.

[0249] Comparative Example 54: The only difference from Example 19 is that the catalyst support is HY and the active component in the catalyst is a Ru and Pd bimetallic active component.

[0250] Comparative Example 55: The only difference from Example 19 is that the catalyst support is TiO2 and the active component in the catalyst is a bimetallic active component of Ru and Re.

[0251] Comparative Example 56: The only difference from Example 19 is that the catalyst support is ZrO2 and the active component in the catalyst is a Ru and Re bimetallic active component.

[0252] Comparative Example 57: The only difference from Example 19 is that the catalyst support is H-ZSM-5 and the active component in the catalyst is a Ru and Re bimetallic active component.

[0253] Comparative Example 58: The only difference from Example 19 is that the catalyst support is HY and the active component in the catalyst is a Ru and Re bimetallic active component.

[0254] Comparative Example 59: The only difference from Example 1 is that activated carbon was used instead of RuRe / CeO2 as the catalyst.

[0255] Comparative Example 60: The only difference from Example 1 is that ZrO2 was used instead of RuRe / CeO2 as the catalyst.

[0256] The results of alkane yields and liquid alkane yields for Examples 1 to 97 and Comparative Examples 1 to 60 are shown in Table 1.

[0257] Table 1. Mass yield of liquid alkanes prepared by hydrogenolysis of mixed plastics of polyolefins and polyethylene terephthalate using different catalysts.

[0258]

[0259]

[0260]

[0261]

[0262]

[0263] As shown in the table above, when the substrate is only low-density polyethylene polymer, and the support is any one of activated carbon, Al2O3, TiO2, ZrO2, MgO2, SiO2, H-ZSM-5, and HY, and the active metal component in the catalyst is at least one of Ru, Pt, Pd, Ni, and Co, the alkane yield is 22.7% or higher, with the yield of liquid alkanes reaching as high as 20.0% or higher. Furthermore, the alkane yields are all higher than those in the comparative example when only one of activated carbon, Al2O3, TiO2, ZrO2, MgO2, SiO2, H-ZSM-5, and HY is used as the catalyst, both in terms of alkane and liquid alkanes.

[0264] Preferably, when the reaction substrate is only low-density polyethylene polymer, the support component is any one of CeO2, TiO2, ZrO2, H-ZSM-5, and HY, and the active metal component in the catalyst is any one of Ru and Pt metals, the alkane yield is as high as 70.9% or more, of which the yield of liquid alkane is as high as 50.9% or more. Furthermore, both the alkane yield and the liquid alkane yield are higher than those in the comparative example when any one of Al2O3, MgO2, and SiO2 is used as the catalyst support.

[0265] Preferably, when the reaction substrate is only low-density polyethylene polymer, and the bimetallic active component in the catalyst consists of at least one of Ru metal and Pt, Pd, or Re metal, and the support component is any one of CeO2, ZrO2, H-ZSM-5, or HY, the alkane yield is as high as 74.0% or more, of which the yield of liquid alkane is as high as 60.9% or more. Furthermore, both the alkane yield and the liquid alkane yield are higher than those in the comparative example when only one of Ru or Pt metals is used as the active site.

[0266] When the reaction substrate is at least one of low-density polyethylene, high-density polyethylene, and polypropylene, and the bimetallic active component of the catalyst consists of Ru and Re metals, and the support component is any one of CeO2, ZrO2, and TiO2, the alkane yield is as high as 79.3% or more, of which the yield of liquid alkane is as high as 65.1% or more. Furthermore, both the alkane yield and the liquid alkane yield are higher than those in the comparative example when only Ru or Pt metals are used as active sites.

[0267] Furthermore, when the reaction substrate is a mixed plastic polymer composed of low-density polyethylene and polyethylene terephthalate, and the support component is CeO2, and the active metal component in the catalyst is composed of any one of Ru or Pt, and the support component is CeO2, the alkane yield is 26.0% or higher, of which the yield of liquid alkane is 21.2% or higher. Moreover, the alkane yields are all higher than those in the comparative example when only one of activated carbon, Al2O3, TiO2, ZrO2, MgO2, SiO2, H-ZSM-5, and HY is used as the catalyst support, both in terms of alkane yield and liquid alkane yield.

[0268] Preferably, when the reaction substrate is a mixed plastic polymer composed of low-density polyethylene and polyethylene terephthalate, and the support component is CeO2, and the active metal component in the catalyst is Ru metal, the alkane yield is 30.4% or more, of which the yield of liquid alkane is 27.3% or more. Furthermore, the alkane yields are higher than those in the comparative example when the support component is CeO2 and the active metal component in the catalyst is composed of any one of Re, Pt, Pd, Ni, Co, Ti, Mo, or Cr metals, as well as the yield of liquid alkane.

[0269] Preferably, when the reaction substrate is a mixed plastic polymer composed of low-density polyethylene and polyethylene terephthalate, and the support component is CeO2, and the bimetallic active component in the catalyst is Ru or Re metal, the alkane yield is as high as 96.1% or more, of which the yield of liquid alkane is as high as 78.2% or more. Furthermore, the alkane yields are higher than those in the comparative example when the support component is CeO2 and the catalyst's metallic active component consists of any one of Ru, Re, Pt, Pd, Ni, Co, Ti, Mo, or Cr metal, as well as the yield of liquid alkane.

[0270] Furthermore, when the reaction substrate is a mixed plastic, and the oxygen-containing plastic in the mixed plastic is at least one of polyethylene terephthalate, polycarbonate, polybutylene terephthalate alcohol, and polyphenylene ether, and the polyolefin plastic in the mixed plastic is low-density polyethylene, and the bimetallic active component in the catalyst is composed of Ru metal and Re metal, and the support component is CeO2, the yield of alkane is as high as 89.9% or more, of which the yield of liquid alkane is as high as 70.9% or more.

[0271] Furthermore, when the reaction substrate is a mixed plastic, and the polyolefin plastic in the mixed plastic is at least one of low-density polyethylene, high-density polyethylene, and polypropylene, and the oxygen-containing plastic in the mixed plastic is polyethylene terephthalate, and the bimetallic active component in the catalyst is composed of Ru metal and Re metal, and the support component is CeO2, the yield of alkane is as high as 87.8% or more, of which the yield of liquid alkane is as high as 67.2% or more.

[0272] Furthermore, when the reaction substrate is a mixed plastic, and the polyolefin plastic in the mixed plastic is a mixture of low-density polyethylene, high-density polyethylene, and polypropylene, and the oxygen-containing plastic in the mixed plastic is a mixture of polyethylene terephthalate, polycarbonate, polybutylene terephthalate alcohol, and polyphenylene ether, and the bimetallic active component in the catalyst is composed of Ru metal and Re metal, and the support component is CeO2, the alkane yield is as high as 81.2% or more, of which the yield of liquid alkane is as high as 54.2% or more.

[0273] Furthermore, when the reaction substrate is a composite mixed plastic, the plastic polymer type is polyvinyl acetate, the bimetallic active component in the catalyst consists of Ru and Re metals, and the support component is CeO2, the alkane yield is as high as 86.1% or more, of which the yield of liquid alkane is as high as 74.0% or more. Therefore, the method of this invention can greatly improve the recycling efficiency of mixed plastic waste, which is difficult to process directly in industry. It achieves relatively thorough conversion of mixtures of single plastic polymers and single plastic polymer products composed of multiple plastics, with an alkane yield of 81% or more, of which the yield of liquid alkane is as high as 54% or more. This significantly improves the direct conversion efficiency of mixed plastics, and the resulting liquid alkane product can be used as liquid fuel without separation.

Claims

1. A method for preparing liquid alkanes by catalytic degradation of waste mixed plastics, characterized in that, The method includes: reacting waste mixed plastics consisting of polyolefin plastics and oxygen-containing plastics with hydrogen under solvent-free conditions at 150-350°C in the presence of a catalyst; separating the reaction products to obtain liquid alkanes; the catalyst includes a support and an active component supported on the support, wherein the active component is at least one of Ru, Re, Pt, Pd, Ni, Co, Mo, and Cr; the support is at least one of activated carbon, metal oxide, and molecular sieve, wherein the metal oxide is at least one of Al2O3, TiO2, ZrO2, CeO2, MgO2, and SiO2, and the molecular sieve is at least one of H-ZSM-5 and HY zeolite.

2. The method according to claim 1, characterized in that, The oxygen-containing plastic in the waste mixed plastic is at least one of polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polycarbonate.

3. The method according to claim 1, characterized in that, The polyolefin plastic in the waste mixed plastic is at least one of high-density linear polyethylene, low-density linear polyethylene, and polypropylene.

4. The method according to claim 1, characterized in that, The mass ratio of polyolefin plastics to oxygen-containing plastics in the waste mixed plastics is 4~20:

1.

5. The method according to claim 1, characterized in that, The mass ratio of the waste mixed plastic to the catalyst is 10~100:

1.

6. The method according to claim 1, characterized in that, The mass ratio of the carrier to the active ingredient is 40~200:

1.

7. The method according to claim 1, characterized in that, The active ingredient is a bimetallic combination consisting of Ru and a metal selected from Pt, Pd, Re, Ni, Co, Mo, and Cr, and the support component is at least one selected from TiO2, ZrO2, CeO2, H-ZSM-5, and HY.

8. The method according to claim 1, characterized in that, The hydrogen pressure is 0.5~10 MPa.

9. The method according to claim 1, characterized in that, The reaction time is 1 to 50 hours.

10. The method according to claim 1, characterized in that, The main components of the liquid alkane product are C7~C6. 17 Straight-chain alkanes, branched alkanes, and / or cycloalkanes.

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