Biphase rare earth metal-based high-entropy oxygen carrier for waste plastic gasification and preparation method and application thereof

Abstract

The invention belongs to the technical field of organic solid waste recycling and high-value conversion, and particularly discloses a double-phase rare earth metal-based high-entropy oxygen carrier for waste plastic gasification and a preparation method and application of the double-phase rare earth metal-based high-entropy oxygen carrier. The oxygen carrier has a general formula of FeaNibCocMgdMeOy, a, b, c, d and e respectively account for 5%-35% of atoms, a + b + c + d + e = 100%, M is rare earth metal Ce or La, and y ranges from 0 to 4 but is not 0. The content of surface oxygen vacancies of the oxygen carrier is increased by a biphase structure formed after introduction of the rare earth metal, lattice oxygen migration is facilitated to participate in gasification reaction, lattice distortion of the high-entropy oxygen carrier occurs, metal-oxygen bonds become weak, oxygen release capacity is further promoted, catalytic cracking capacity on waste plastics is improved, and the catalytic cracking efficiency of the high-entropy oxygen carrier is improved. The yield of the synthesis gas and the cycling stability of the oxygen carrier are improved. The oxygen carrier disclosed by the invention is simple in preparation method, can be widely applied to the field of waste plastic gasification, and has relatively high use value.

Description

Technical Field

[0001] This invention belongs to the field of organic solid waste resource utilization and high-value conversion technology, specifically relating to a two-phase rare earth metal-based high-entropy oxygen carrier for waste plastic gasification, its preparation method and uses. Background Technology

[0002] With the acceleration of global economic growth and urbanization, the annual output of waste plastics is increasing, while the overall resource utilization rate remains low. Traditional disposal methods such as landfill and incineration are prone to causing environmental pollution problems, making it urgent to develop green and high-value waste plastic disposal technologies.

[0003] Gasification technology has attracted much attention due to its strong adaptability to raw materials, flexible reaction, and wide range of applications for the syngas produced. Catalytic gasification technology can convert waste plastics into hydrogen-rich syngas, achieving high-value resource utilization. However, conventional gasification uses gaseous gasifying agents (such as air or steam), which easily dilutes the syngas, reducing its calorific value and increasing the difficulty of product control. Chemical looping gasification technology based on oxygen carriers can effectively solve these problems. As the core medium for heat and mass transfer, the reactivity and cycle stability of the oxygen carrier directly determine the gasification efficiency and syngas quality. Currently, the development of oxygen carriers for waste plastic gasification still faces two major challenges: (1) Insufficient catalytic cracking capacity: The carbon content of waste plastics is over 60%, resulting in a low carbon conversion rate during gasification. An ideal oxygen carrier not only needs to provide lattice oxygen to achieve partial oxidation (generating CO), but also needs to have a strong catalytic cracking capacity for the CH and CC bonds in the waste plastic components, promoting efficient bond breaking and rearrangement of intermediates to generate syngas (CO+H2). (2) Poor cycle stability: Currently widely used iron-based (such as Fe2O3, ilmenite) and other transition metal-based oxygen carriers are prone to deactivation due to sintering during the reaction, leading to a decrease in cycle stability. Developing oxygen carriers with high catalytic cracking capacity and high stability is crucial for the efficient production of syngas from organic solid waste gasification.

[0004] Existing reports still have limitations in addressing the aforementioned challenges: Literature [J. ECM, 2018, 168: 288-295] reports the use of Fe2O3 oxygen carriers for chemical looping gasification, but this material is prone to sintering during cycling, resulting in a significant decrease in specific surface area and poor stability. Chinese patent CN202211008688.9 proposes doping Co into CeO2 to form a Ce-Co-O solid solution low-entropy oxygen carrier to improve stability. However, this system is mainly designed for the conversion of small molecules such as methane; its catalytic cracking efficiency for complex, difficult-to-crack waste plastic macromolecules remains unclear. Chinese patent CN202310785721.7 discloses a transition metal high-entropy oxygen carrier such as (MnFeCoNiCu)O. 4-xOr its modified forms. Although the design of high entropy and transition metals improves structural stability and oxygen release capacity, it tends to lead to the complete oxidation of fuel to produce CO2 rather than the desired CO in the reaction, which is not conducive to the control of syngas quality. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings of existing technologies by providing a biphase rare-earth metal-based high-entropy oxygen carrier for waste plastic gasification, its preparation method, and its applications. The method utilizes the inherent differences in valence and atomic size among metal elements to synthesize the biphase rare-earth metal-based high-entropy oxygen carrier. The biphase structure formed after the introduction of rare-earth metals enhances the surface oxygen vacancy content of the oxygen carrier, facilitating lattice oxygen migration and participation in the gasification reaction, achieving partial oxidation. Simultaneously, the high-entropy oxygen carrier lattice undergoes distortion, weakening the metal-oxygen bond, thereby promoting oxygen release and enhancing the catalytic cracking ability of the oxygen carrier. This further catalytically cracks carbon-containing small molecule gases that have not fully participated in redox reactions, ultimately achieving a simultaneous improvement in syngas yield and cycle stability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first objective of this invention is to provide a two-phase rare-earth metal-based high-entropy oxygen carrier for waste plastic gasification, wherein the oxygen carrier has the general formula Fe a Ni b Co c Mg d M e O y Where a, b, c, d, and e are atomic percentages of 5% to 35%, and satisfy a+b+c+d+e=100%, M is a rare earth metal Ce or La, and y ranges from 0 to 4, but is not 0. The oxygen carrier has a spinel-type cubic crystal structure and a cerium oxide fluorite crystal structure or a spinel-type hexagonal crystal structure and a lanthanum oxide crystal structure. The oxygen type of the oxygen carrier is analyzed using X-ray photoelectron spectroscopy, and the oxygen vacancy concentration is analyzed by comparing the ratio δ of chemisorbed oxygen / lattice oxygen, where the ratio δ is 0.3 to 0.8.

[0007] Furthermore, the dual-phase rare-earth metal-based high-entropy oxygen carrier can achieve at least 10 redox cycles in a temperature range of 500~800°C.

[0008] A second objective of this invention is to provide a method for preparing the aforementioned dual-phase rare-earth metal-based high-entropy oxygen carrier, comprising: Five metal precursors were dissolved in an organic solvent according to the target atomic ratio; The crystalline product was obtained through a solvothermal reaction. The crystalline product was dried and then calcined to obtain the dual-phase rare earth metal-based high-entropy oxygen carrier.

[0009] Furthermore, the organic solvent includes at least one of ethylene glycol or ethanol.

[0010] Furthermore, the temperature of the solvothermal reaction is 90~180°C.

[0011] Furthermore, the drying temperature is 80~110°C, and the drying time is 10~24h.

[0012] Furthermore, the calcination process is as follows: the heating rate is 1-25°C / min, the first stage pyrolysis temperature is 350-500°C, and the calcination time is 2-5h; the second stage pyrolysis temperature is 750-950°C, and the calcination time is 2-5h.

[0013] A third objective of this invention is to provide the application of the above-mentioned dual-phase rare-earth metal-based high-entropy oxygen carrier in chemical looping combustion.

[0014] A fourth objective of this invention is to provide the application of the above-mentioned dual-phase rare earth metal-based high-entropy oxygen carrier in waste plastic gasification.

[0015] Furthermore, the waste plastics, as hydrocarbon donors in the chemical chain system, participate in redox, catalytic cracking, and gasification reforming processes to produce hydrogen and carbon monoxide.

[0016] Compared with existing technologies, the beneficial effects of the technical solution provided by this invention are as follows: (1) The dual-phase rare earth metal-based high-entropy oxygen carrier constructed in this invention has the general formula Fe a Ni b Co c Mg d M e O y M represents a rare earth metal, Ce or La, where a, b, c, d, and e represent atomic percentages ranging from 5% to 35%, satisfying a+b+c+d+e=100%, and y ranges from 0 to 4, but is not zero. The biphase structure formed by the introduction of rare earth metals enhances the surface oxygen vacancy content of the oxygen carrier, facilitating lattice oxygen migration and participation in the gasification reaction, achieving partial oxidation. Simultaneously, the high-entropy oxygen carrier lattice undergoes distortion, weakening the metal-oxygen bond, thereby promoting oxygen release and enhancing the catalytic cracking ability of the oxygen carrier. This allows for further catalytic cracking of carbon-containing small molecules that have not fully participated in redox reactions, ultimately achieving a simultaneous improvement in syngas yield and cycle stability.

[0017] (2) The dual-phase rare earth metal-based high-entropy oxygen carrier provided by the present invention has a multi-metal synergistic effect, which enables the formation of a large number of stable oxygen vacancy channels in the material, and can quickly provide lattice oxygen during the plastic pyrolysis process, thereby improving the oxidation and reforming efficiency of the pyrolysis products.

[0018] (3) The dual-phase rare earth metal-based high-entropy oxygen carrier provided by the present invention has excellent anti-sintering ability, maintains a certain original crystal structure after oxygen release, and has strong cycle stability.

[0019] (4) The oxygen carrier preparation method in this invention is simple and can be widely used in the field of waste plastic gasification, and has high application value. Attached Figure Description

[0020] Figure 1 The crystal structure test results are for Example 1 and Comparative Examples 3 and 4; Figure 2 For testing the catalytic cracking capacity of Example 1 and Comparative Examples 3 and 4; Figure 3 Examples 1 and 2 are cyclic stability performance tests. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments and accompanying drawings are described in further detail below. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0022] The present invention provides a two-phase rare-earth metal-based high-entropy oxygen carrier for waste plastic gasification, the oxygen carrier having the general formula Fe a Ni b Co c Mg d M e O y M is a rare earth metal, Ce or La, where a, b, c, d, and e have atomic percentages ranging from 5% to 35%, satisfying a+b+c+d+e=100%. y ranges from 0 to 4, but is not zero, to maintain charge balance. This oxygen carrier exhibits high structural stability, rapid oxygen mobility, and strong reversible redox properties under high-temperature conditions.

[0023] The oxygen carrier provided by this invention exhibits a spinel-type cubic crystal structure with cerium oxide and fluorite, or a spinel-type hexagonal crystal structure with lanthanum oxide. This provides more oxygen vacancies, facilitating oxygen dissociation and migration, and making it suitable for continuous chemical chaining processes. The oxygen type of the oxygen carrier is analyzed using X-ray photoelectron spectroscopy (XPS), and the oxygen vacancy concentration is analyzed by comparing the ratio δ of chemisorbed oxygen to lattice oxygen; the ratio δ is 0.3~0.8.

[0024] In this invention, "chemical chaining" refers to a class of reaction processes that utilize solid oxygen carriers to provide cyclic oxygen, including: chemical chaining combustion, chemical chaining hydrogen production, chemical chaining pyrolysis, and chemical chaining gasification. Chemical chains can include waste plastics as a source of reducing agents. More specifically, waste plastics can serve as hydrocarbon donors in the chemical chaining system, participating in redox, catalytic pyrolysis, and gasification reforming processes.

[0025] The chemical chain process of the present invention can use waste plastics (such as PE, PP, PS, etc.) as reducing agents or hydrocarbon raw materials, and realize the combustion, pyrolysis, hydrogen production or carbon monoxide production of waste plastics through the cyclic oxidation-reduction reaction of oxygen carrier.

[0026] The dual-phase rare-earth metal-based high-entropy oxygen carrier provided by this invention can be prepared by solution methods, wet chemical methods, or solid-phase methods, including but not limited to co-precipitation methods, sol-gel methods, solvothermal methods, hydrothermal methods, solid-phase mixing methods, etc. The preferred method of this invention is the solvothermal method, and the more specific steps are as follows: (1) Five metal salts (nitrate, chloride, acetate or organometallic salt) are added to an organic solvent at a preset atomic ratio to fully dissolve and mix them to form a homogeneous metal precursor system; in some embodiments, the organic solvent may be selected from ethylene glycol or ethanol.

[0027] (2) In a closed environment at a temperature of 90~180°C, metal elements are uniformly distributed at the atomic or nanoscale through solvothermal crystallization to obtain an oxygen carrier precursor. Too low a temperature will result in incomplete crystallization and poor grain dispersion; too high a temperature may accelerate agglomeration, resulting in coarse grains. In this invention, the temperature can be selected from any specific temperature between 90 and 180°C, for example 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 110°C, 112°C, 113°C, 114°C, 115°C, 116°C, 117°C, 118°C, 119°C, 120°C, etc., which will not be elaborated here.

[0028] (3) Dry the oxygen carrier precursor at 80~110°C for 10~24 h to age it and promote structural stabilization.

[0029] (4) Calcination solid-state transformation is carried out, that is, the heating rate is 1~25°C / min, the first stage pyrolysis temperature is 350~500°C, and the calcination time is 2~5h to remove organic components and avoid impurities generated by high-temperature calcination; the second stage pyrolysis temperature is 750~950°C, and the calcination time is 2~5h to obtain a two-phase rare earth metal-based high-entropy oxygen carrier. During the calcination process, the metal oxide undergoes solid-state diffusion and lattice rearrangement to form a stable high-entropy structure; the calcination atmosphere can be air, oxygen or inert gas, and if necessary, a reducing gas can be added to control the oxygen vacancy concentration; the grain size, specific surface area and oxygen migration ability can be adjusted by controlling the heating rate, holding time and annealing method.

[0030] The embodiments of the present invention have achieved some positive results in the research and development or use process, and have indeed great advantages compared with the prior art. The biphase cerium-based high-entropy oxygen carrier and the biphase lanthanum-based high-entropy oxygen carrier provided by the present invention are particularly suitable for waste plastic gasification, and exhibit excellent oxygen release capacity and catalytic cracking capacity. The following content is described in conjunction with the data, charts and other information of the experimental process.

[0031] Example 1 Ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and cerium nitrate precursors were weighed into beakers in an atomic ratio of 1:1:1:1:1 to prepare a biphase cerium-based high-entropy oxygen carrier. Ethylene glycol solvent was added to the beaker containing the metals in the specified proportions and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain the biphase cerium-based high-entropy oxygen carrier, denoted as HEO-Ce.

[0032] Example 2 Ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and lanthanum nitrate precursors were weighed into beakers in an atomic ratio of 1:1:1:1:1 to prepare a biphase lanthanum-based high-entropy oxygen carrier. Ethylene glycol solvent was added to the beaker containing the metals in the specified ratio and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain the biphase lanthanum-based high-entropy oxygen carrier, denoted as HEO-La.

[0033] Example 3 Ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and cerium nitrate precursors were weighed into beakers with a metal atomic ratio of Co:Fe:Ni:Mg:Ce = 28:13:13:13:13 to prepare a non-uniform cerium-based high-entropy oxygen carrier. Ethylene glycol solvent was added to the beaker containing the metals in the specified proportions and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain a biphase cerium-based high-entropy oxygen carrier with a Co content of 35%, denoted as HEO-Ce(Co). 35 ).

[0034] Example 4 Ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and cerium nitrate precursors were weighed into beakers with a metal atomic ratio of Mg:Fe:Ni:Co:Ce = 28:13:13:13:13 to prepare a non-uniform cerium-based high-entropy oxygen carrier. Ethylene glycol solvent was added to the beaker containing the metals in the specified proportions and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain a biphase cerium-based high-entropy oxygen carrier with a Mg content of 35%, denoted as HEO-Ce(Mg 35 ).

[0035] Comparative Example 1 Compared with oxygen carriers without rare earth metals, ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and aluminum nitrate precursors were weighed into beakers in a metal atomic ratio of 1:1:1:1:1. Ethylene glycol solvent was added to the beakers containing the metals in the specified ratio and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain the high-entropy oxygen carrier, denoted as HEO-Al.

[0036] Comparative Example 2 Compared with oxygen carriers without rare earth metals, ferric nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, and copper nitrate precursors were weighed into beakers in a metal atomic ratio of 1:1:1:1:1. Ethylene glycol solvent was added to the beakers containing the metals in the specified ratio and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain the high-entropy oxygen carrier, denoted as HEO-Cu.

[0037] Comparative Example 3 Compared with rare-earth metal-free oxygen carriers, ferric nitrate, cobalt nitrate, nickel nitrate, and magnesium nitrate precursors were weighed into beakers in a metal atomic ratio of 1:1:1:1. Ethylene glycol solvent was added to the beakers containing the metals in the specified ratio and allowed to dissolve uniformly by ultrasonication. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain a quaternary medium-entropy oxygen carrier, denoted as Fe-Ni-Co-Mg.

[0038] Comparative Example 4 Compared with rare-earth metal-free oxygen carriers, ferric nitrate, cobalt nitrate, and nickel nitrate precursors were weighed into beakers in a 1:1:1 ratio. Ethylene glycol solvent was added to the beakers containing the metals and the mixture was sonicated to dissolve them uniformly. The resulting homogeneous solution was then subjected to solvothermal crystallization at 105°C for 12 hours. After the reaction, the solution was dried at 105°C for 24 hours. The dried sample was then calcined at 400°C for 3 hours, followed by calcination at 800°C for another 3 hours to obtain a ternary medium-entropy oxygen carrier, denoted as Fe-Ni-Co.

[0039] The crystal structures of the HEO-Ce obtained in Example 1 and the Fe-Ni-Co-Mg and Fe-Ni-Co oxygen carriers obtained in Comparative Examples 3 and 4 were tested, and the results are as follows: Figure 1 As shown. In the absence of Ce, both Fe-Ni-Co-Mg and Fe-Ni-Co are single-phase spinel structures. When Ce is introduced, spinel-type and cerium oxide fluorite structures are formed.

[0040] The catalytic cracking capabilities of the HEO-Ce obtained in Example 1 and the Fe-Ni-Co-Mg and Fe-Ni-Co oxygen carriers obtained in Comparative Examples 3 and 4 were tested under a simulated polypropylene plastic pyrolysis atmosphere (12.30 vol% CH4, 4.39 vol% C2H4, 0.51 vol% C2H6, 82.80 vol% N2). The results are as follows. Figure 2 As shown, the oxygen carrier weight gain rate represents the catalytic cracking ability; the catalytic cracking ability of the oxygen carrier is significantly enhanced after the introduction of Ce.

[0041] Oxygen type tests were performed on the HEO-Ce obtained in Example 1 and the Fe-Ni-Co-Mg and Fe-Ni-Co oxygen carriers obtained in Comparative Examples 3 and 4. The results are shown in Table 1. After the introduction of Ce, the physical adsorption and chemical adsorption of oxygen in the oxygen carrier increased, indicating that Ce promoted the dispersion of the oxygen carrier structure and reduced the bulk structure. The increased ratio of chemically adsorbed oxygen to lattice oxygen indicates that Ce increased the surface oxygen vacancy content of the oxygen carrier, thereby promoting oxygen migration and release to participate in the gasification reaction. The oxygen type was analyzed using X-ray photoelectron spectroscopy.

[0042] Table 1. Results of oxygen type tests using different oxygen carriers.

[0043]

[0044] Polypropylene (PP) waste plastic gasification experiments were conducted on the oxygen carriers obtained in Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4. 0.5 g of PP waste plastic and 0.5 g of oxygen carrier were weighed and placed in the pyrolysis reactor and gasification reactor, respectively. 100 mL / min N2 was used as the carrier gas. The pyrolysis temperature was 500°C, and the gasification temperature was 800°C. The steam rate was 6 mL / h, and the water injection time was 20 min. The activity of waste plastic gasification was evaluated by analyzing the components and concentrations using gas chromatography. The calculation formulas for the yields of H2, CO, and syngas are shown in formulas (1), (2), and (3), respectively, and the yield results are shown in Table 2. The results show that the yields of H2, CO, and syngas obtained by the biphase rare earth metal-based high-entropy oxygen carriers in Examples 1, 2, 3, and 4 after waste plastic gasification are significantly higher than the yields without rare earth metal oxygen carriers in Comparative Examples 1, 2, 3, and 4.

[0045]

[0046]

[0047]

[0048] Table 2. Results of vaporization experiments with different oxygen carriers.

[0049]

[0050] Gasification experiments were conducted on polystyrene (PS), high-density polyethylene (HDPE), and PP+PS+HDPE waste plastics using the HEO-La oxygen carrier obtained in Example 2. 0.5 g of waste plastic and 0.5 g of HEO-La oxygen carrier were weighed and placed in the pyrolysis reactor and gasification reactor, respectively. 100 mL / min N2 was used as the carrier gas. The pyrolysis temperature was 500°C, and the gasification temperature was 800°C. The steam rate was 6 mL / h, and the water injection time was 20 min. The activity evaluation of waste plastic gasification is shown in Table 3. The results show that, under the action of the HEO-La oxygen carrier, high yields of syngas were obtained from different types of waste plastics and mixed plastics.

[0051] Table 3. Results of gasification experiments on different types of waste plastics and mixed plastics.

[0052]

[0053] The HEO-Ce and HEO-La high-entropy oxygen carriers obtained in Examples 1 and 2 were compared with other literature oxygen carriers ((CoNiCuZnMg)Fe2O4, NiFe... 20 O x The yields of H2, CO, and syngas were compared, and the results are shown in Table 4. The results indicate that, under the action of the high-entropy oxygen carrier in this embodiment of the invention, the gas yield obtained after gasification of waste plastics is significantly improved.

[0054] Table 4

[0055] The HEO-Ce and HEO-La high-entropy oxygen carriers obtained in Examples 1 and 2 were subjected to cyclic stability tests, such as... Figure 3 As shown in the figure. The results indicate that the syngas yield of the HEO-Ce oxygen carrier remained stable during 10 cycles of the oxygen carrier, and the syngas yield of the HEO-La oxygen carrier also remained stable after a slight decrease, indicating good cycling stability.

[0056] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A two-phase rare-earth metal-based high-entropy oxygen carrier for waste plastic gasification, characterized in that, The oxygen carrier has the general formula Fe a Ni b Co c Mg d M e O y Where a, b, c, d, and e are atomic percentages of 5% to 35%, and satisfy a+b+c+d+e=100%, M is a rare earth metal Ce or La, and y ranges from 0 to 4, but is not 0. The oxygen carrier has a spinel-type cubic crystal structure and a cerium oxide fluorite crystal structure or a spinel-type hexagonal crystal structure and a lanthanum oxide crystal structure. The oxygen type of the oxygen carrier is analyzed using X-ray photoelectron spectroscopy, and the oxygen vacancy concentration is analyzed by comparing the ratio δ of chemisorbed oxygen / lattice oxygen, where the ratio δ is 0.3 to 0.

8.

2. The dual-phase rare-earth metal-based high-entropy oxygen carrier for waste plastic gasification according to claim 1, characterized in that, At least 10 redox cycles can be achieved within a temperature range of 500~800°C.

3. A method for preparing a dual-phase rare-earth metal-based high-entropy oxygen carrier as described in any one of claims 1-2, characterized in that, include: Five metal precursors were dissolved in an organic solvent according to the target atomic ratio; Oxygen carrier precursors were obtained via a solvothermal method. The oxygen carrier precursor was dried and then calcined to obtain the dual-phase rare earth metal-based high-entropy oxygen carrier.

4. The preparation method according to claim 3, characterized in that, The organic solvent includes at least one of ethylene glycol or ethanol.

5. The preparation method according to claim 3, characterized in that, The temperature for the solvothermal method is 90~180°C.

6. The preparation method according to claim 3, characterized in that, The drying temperature is 80~110°C, and the drying time is 10~24h.

7. The preparation method according to claim 3, characterized in that, The calcination process is as follows: the heating rate is 1~25°C / min, the first stage pyrolysis temperature is 350~500°C, and the calcination time is 2~5h; the second stage pyrolysis temperature is 750~950°C, and the calcination time is 2~5h.

8. The application of the biphase rare earth metal-based high-entropy oxygen carrier as described in claim 1 or 2 in chemical looping combustion.

9. The application of the dual-phase rare earth metal-based high-entropy oxygen carrier as described in claim 1 or 2 in the gasification of waste plastics.

10. The application according to claim 9, characterized in that, The waste plastics, as hydrocarbon donors in the chemical chain system, participate in redox, catalytic cracking and gasification reforming processes to produce hydrogen and carbon monoxide.

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