Method for preparing porous calcium-based energy storage material by using waste plastic as pore-forming template

Abstract

The invention discloses a method for preparing a porous calcium-based energy storage material by using waste plastics as a pore-forming template, which comprises the following steps: adding the waste plastics into an organic solvent, and stirring to completely dissolve the plastics to obtain the pore-forming template; the preparation method comprises the following steps: mixing a calcium source raw material with a doped element precursor, adding a pore-forming template, mixing and stirring, and removing an organic solvent to obtain a mixture; performing pyrolysis treatment on the mixture in an inert atmosphere to obtain a volatile product and pyrolysis residues; in the pyrolysis process, the plastic template is decomposed to generate a high-calorific-value liquid oil product and combustible gas which can be used as energy products to realize co-production utilization. According to the method, high-valued utilization of the waste plastic and efficient preparation of the porous calcium-based material are realized, and a deep synergistic system of solid waste resource utilization and material functional preparation is constructed.

Description

Technical Field

[0001] This invention relates to the field of organic solid waste disposal and thermochemical energy storage material preparation technology, specifically to a method for preparing porous calcium-based energy storage materials using waste plastics as pore-forming templates. Background Technology

[0002] With the acceleration of industrialization and urbanization, the output of waste plastics is increasing year by year. Plastics possess stable chemical properties and excellent physical properties, and are widely used in packaging, building materials, home appliances, automobiles, and other fields. However, this also generates a large amount of solid waste that is difficult to degrade and treat. Traditional waste plastic treatment methods mainly include landfill, incineration, and mechanical recycling. Landfill not only occupies a large amount of land resources but may also lead to the seepage of harmful substances into the soil and groundwater; incineration easily releases toxic gases such as dioxins and hydrogen chloride, causing air pollution; mechanical recycling is limited in its application due to the wide variety of plastics and high recycling costs. Therefore, how to achieve efficient resource utilization of waste plastics has become an urgent technical problem to be solved.

[0003] On the other hand, with the development of renewable energy and carbon neutrality goals, thermochemical energy storage, as a high-energy-density and reversibly recyclable energy storage method, has attracted widespread attention. Among them, calcium-based thermochemical energy storage systems based on the calcium oxide / calcium carbonate reaction pair have advantages such as moderate reaction temperature, inexpensive and readily available raw materials, and high cycle stability, and are considered an important approach for large-scale energy storage and carbon dioxide capture in the future. However, calcium-based energy storage materials generally suffer from sintering and pore structure collapse during multiple cycles, leading to a significant reduction in activity and insufficient cycle performance, which limits their practical application. To address these issues, researchers have proposed methods such as doping modification and pore formation control, but these still suffer from problems such as complex processes, high costs, or unstable pore structures.

[0004] In recent years, template methods have been considered an effective way to control the pore structure of energy storage materials. By introducing organic materials as templates, porous structures can be formed during heat treatment, thereby improving the specific surface area and cycle stability of the material. Waste plastics are abundant, have high hydrocarbon content, and can produce high-calorific-value oil and gas byproducts during pyrolysis. If they are used as pore-forming templates in the preparation of calcium-based thermochemical energy storage materials, they can not only effectively construct porous structures and improve the material's cycle performance, but also realize the resource utilization of waste plastics, which has significant economic and environmental implications. Summary of the Invention

[0005] To overcome the problems of high energy consumption, severe pollution, and insufficient resource utilization in existing waste plastic treatment methods, as well as the pore blockage and rapid activity decay of calcium-based thermochemical energy storage materials during cycling, this invention provides a method for preparing porous calcium-based energy storage materials using waste plastics as pore-forming templates. This method effectively achieves high-value utilization of waste plastics, improves the pore structure and cycling stability of calcium-based energy storage materials, and synergistically produces high-calorific-value liquid oil and pyrolysis gas during the preparation process, achieving dual benefits in terms of energy and environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template, the specific steps of which are as follows: Waste plastic is added to an organic solvent and stirred until the plastic is completely dissolved to obtain a hole-forming template; After mixing the calcium source material with the doped element precursor, a pore-forming template is added and stirred to remove the organic solvent, resulting in a mixture. The mixture was subjected to pyrolysis under an inert atmosphere to obtain volatile products and pyrolysis residues; The pyrolysis residue was calcined at high temperature to obtain a porous calcium-based thermochemical energy storage material with a specific surface area greater than 15 m². 2 / g.

[0007] Furthermore, the volatile products are condensed to obtain condensed liquid products and non-condensable gases. The condensed liquid products are liquid oil products, and the non-condensable gases are pyrolysis gases. The yield of the liquid oil products is greater than 20 wt%, with a calorific value greater than 35 MJ / kg, and the yield of the pyrolysis gases is greater than 15 wt%, with a calorific value greater than 18 MJ / Nm³. 3 .

[0008] Furthermore, the waste plastic is at least one of polystyrene, polypropylene, polyethylene, polyvinyl chloride, and polymethyl methacrylate, with a particle size of 100 μm to 500 μm.

[0009] Furthermore, the organic solvent is at least one selected from carbon tetrachloride, benzene, toluene, acetone, dichloromethane, and carbon tetrachloride.

[0010] Furthermore, the calcium source material is at least one of calcium carbonate, calcium hydroxide, calcium oxide, and calcium nitrate.

[0011] Furthermore, the mass ratio of the waste plastic to the calcium source raw material is 10:90 to 30:70, the stirring temperature is 80℃ to 120℃, and the stirring time is 2h to 5h.

[0012] Furthermore, the precursor of the doping element is a nitrate or acetate of zinc, magnesium, iron, manganese, aluminum, zirconium, or any combination thereof.

[0013] Furthermore, after mixing the calcium source material with an element molar ratio of 100:(5-15) with the doped element precursor, a pore-forming template is added and the mixture is stirred for 0.5-3 hours. The organic solvent is then removed by vacuum distillation or direct evaporation to obtain the mixture.

[0014] Furthermore, the pyrolysis heating rate is 100℃ / s to 200℃ / s, the pyrolysis temperature is 500℃ to 700℃, and the holding time is 0.5h to 2h; the inert atmosphere is at least one of nitrogen, argon, and helium.

[0015] Furthermore, the calcination temperature is 800℃~950℃, the calcination time is 1h~3h, and the calcination atmosphere is at least one of air, oxygen, and carbon dioxide.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention proposes a method for preparing porous calcium-based energy storage materials using waste plastics as pore-forming templates. Firstly, this method innovatively transforms waste plastics into templates for preparing high-value-added materials. The plastics are dissolved in organic solvents to form a uniformly dispersed pore-forming system, realizing a resource-based utilization model from waste materials. This process not only solves the problems of high energy consumption and heavy pollution associated with traditional plastic processing methods, but also constructs a calcium-based material precursor with a hierarchical pore structure through the template method. Compared to conventional pore-forming methods such as mechanical crushing or chemical corrosion, the waste plastic template can form a continuous, interconnected three-dimensional pore network during pyrolysis, enabling the specific surface area of ​​the final product to exceed 15 m². 2 / g, pore connectivity is improved by more than 40%, providing sufficient material transport channels for the calcium oxide / calcium carbonate cycle reaction.

[0017] This invention significantly improves the thermochemical cycling stability of calcium-based energy storage materials through the synergistic effect of template control and elemental doping. Experiments show that porous calcium-based materials prepared using polyethylene or polypropylene templates retain over 85% of their reactivity after 15 cycles, while the activity decay rate of traditional bulk materials exceeds 60%. This performance improvement stems from two mechanisms: first, the carbonaceous residues formed from the pyrolysis of waste plastics inhibit the sintering and agglomeration of calcium oxide particles; second, the in-situ enrichment of dopant elements on the surface of the template pores forms a composite oxide interface with anti-sintering capabilities. Of particular note is that this method can simultaneously recover high-calorific-value liquid oil (yield of 65%–75% of the mass of waste plastics) and hydrogen-rich pyrolysis gas (calorific value ≥25 MJ / m³) during the pyrolysis process. 3 This enables the cascade utilization of energy from energy storage material preparation and fuel production.

[0018] The core steps of this invention consist of only four stages: template preparation, mixing and molding, pyrolysis pore formation, and calcination activation. The entire process requires no high-pressure reactor or precision temperature control equipment. In terms of raw material compatibility, it can process common plastics such as polyethylene and polypropylene, and is also compatible with recalcitrant wastes such as polystyrene and PET, reducing raw material costs compared to traditional template methods. Attached Figure Description

[0019] Figure 1 The conversion rate of calcium oxide in the multi-cycle calcium-based material in Example 1 of this invention is given. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] This invention provides a method for preparing porous calcium-based energy storage materials using waste plastics as pore-forming templates, specifically comprising the following steps: (1) Weigh the waste plastic and calcium source raw materials according to the mass ratio of 10:90 to 30:70 respectively. Then add the waste plastic to the organic solvent and stir for 2 to 5 hours at 80℃ to 120℃ to completely dissolve the plastic and form a hole-forming template.

[0022] Preferably, the plastic is at least one of polystyrene, polypropylene, polyethylene, polyvinyl chloride, and polymethyl methacrylate, with a particle size of 100 μm to 500 μm.

[0023] Preferably, the calcium source is at least one of calcium carbonate, calcium hydroxide, calcium oxide, and calcium nitrate.

[0024] Preferably, the organic solvent is at least one of carbon tetrachloride, benzene, toluene, acetone, and dichloromethane.

[0025] (2) The calcium source material with an element molar ratio of 100:(5~15) is mixed with the doped element precursor at a certain molar ratio and mixed with the pore-forming template obtained in step (1) for 0.5 h~3 h. Then the organic solvent is removed by vacuum distillation or direct evaporation to obtain the mixture.

[0026] Preferably, the precursor of the doping element is a nitrate or acetate of a metal element such as zinc, magnesium, iron, manganese, aluminum, zirconium, or any combination thereof.

[0027] (3) The mixture obtained is subjected to pyrolysis treatment under an inert atmosphere at 500℃~700℃ for 0.5h~2h, with a heating rate of 100℃ / s~200℃ / s, so that the plastic template is decomposed and partially converted into volatile products. During the calcination process, the small molecule volatile products can play a pore-forming role, thereby significantly increasing the specific surface area of ​​the heat storage material. During this process, the condensed liquid products (liquid oil) are collected by a condensation device, and the non-condensable gas (pyrolysis gas) is collected by a gas collection system. The obtained pyrolysis residue is mainly a calcium precursor and a composite of doped metal oxides.

[0028] Preferably, the inert atmosphere is at least one of nitrogen, argon, and helium.

[0029] Preferably, the yield of liquid oil generated during pyrolysis is greater than 20 wt%, with a calorific value greater than 35 MJ / kg, and the yield of pyrolysis gas is greater than 15 wt%, with a calorific value greater than 18 MJ / Nm³. 3 .

[0030] (4) The pyrolysis residue obtained in step (3) is calcined at 800℃~950℃ for 1h~3h to obtain a porous calcium-based thermochemical energy storage material.

[0031] Preferably, the calcination atmosphere is at least one of air, oxygen, and carbon dioxide.

[0032] Preferably, calcium-based thermochemical energy storage materials are used in calcium oxide / calcium carbonate thermochemical cycle energy storage systems or in carbon dioxide capture and release processes.

[0033] This invention utilizes waste plastics as a pore-forming template, realizing the transformation of waste into materials, reducing environmental pollution, and achieving good economic and ecological benefits. By introducing a plastic template, porous calcium-based energy storage materials are effectively constructed, significantly improving the specific surface area and pore structure stability of the materials, and enhancing the reactivity and cycle stability of the calcium oxide / calcium carbonate thermochemical cycle. High-calorific-value liquid oil and pyrolysis gas are simultaneously obtained during the preparation process, achieving synergistic coupling between energy storage material preparation and fuel production, resulting in high energy utilization efficiency. The process route is simple, the raw material sources are wide-ranging, and it is suitable for large-scale promotion and application.

[0034] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0035] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0036] The calculation methods for liquid oil yield and calcium oxide conversion rate in the following examples are as follows: Liquid oil yield = (liquid oil mass ÷ plastic raw material mass) × 100%.

[0037] Calcium oxide conversion rate = (Sample mass after Nth carbonation reaction - Sample mass after Nth calcination reaction) ÷ Sample mass after Nth calcination reaction In the following examples, the calorific value of liquid oil products was measured using the bomb calorimetry method.

[0038] Unless otherwise specified, all percentages in the following examples are mass percentages.

[0039] Example 1 Waste polypropylene plastic was selected as the template agent, calcium carbonate as the calcium source, and zirconium nitrate as the precursor for doping elements. The specific operation is as follows: (1) Weigh waste polypropylene powder with a particle size of about 200 μm and calcium carbonate at a mass ratio of 20:80. Add the polypropylene powder to toluene solvent and stir magnetically at 80°C for 2 h to allow the polypropylene to partially swell and be uniformly dispersed in the solvent, thus obtaining a pore-forming template.

[0040] (2) Calcium carbonate and zirconium nitrate are mixed at an elemental molar ratio of 100:10, and then mixed with the pore-forming template prepared in step (1). The mixture is stirred for 1 h, and then the solvent is removed under reduced pressure to obtain a dry mixture.

[0041] (3) Under a nitrogen atmosphere, the dried mixture was heated to 600℃ and held for 1 h to decompose the plastic template. During the pyrolysis process, a pale yellow liquid oil was collected by a condenser, with a yield of approximately 23 wt% and a higher heating value of approximately 39 MJ / kg; at the same time, pyrolysis gas was collected, with a yield of approximately 15 wt% and a heating value of approximately 21 MJ / Nm. 3 .

[0042] (4) The pyrolysis residue was calcined at 900°C for 2 h in air atmosphere to obtain a porous CaO-Zr composite material.

[0043] Performance tests show that the specific surface area of ​​the CaO-Zr composite material reaches 18.6 m². 2 / g, pore volume 0.28 cm³ 3 / g. For example... Figure 1As shown, in the calcium oxide / calcium carbonate cycling experiment, under exothermic conditions of 850℃ and thermal storage conditions of 750℃, the calcium oxide conversion rate remained above 92% of the initial absorption rate after 20 cycles. The control material prepared solely by the plastic template method without doping (denoted as P-CaO) maintained approximately 60%, the control material prepared solely by doping without the plastic template method (denoted as Z-CaO) maintained approximately 72%, and the undoped control material prepared without the plastic template method (denoted as Pure-CaO) maintained only approximately 40%. These results indicate that this method significantly improves the cycling stability of calcium-based energy storage materials.

[0044] Example 2 Waste polystyrene was used as a template agent, calcium hydroxide as a calcium source, and aluminum nitrate as a doping precursor.

[0045] (1) Weigh polystyrene powder with a particle size of about 300 μm and calcium hydroxide at a mass ratio of 30:70. Add the polystyrene powder to dichloromethane solvent and stir at 60°C for 3 h to obtain a pore-forming template.

[0046] (2) Calcium hydroxide and aluminum nitrate were mixed at an elemental molar ratio of 100:15, and then mixed evenly with the pore-forming template. The mixture was stirred for 0.5 h, and then the solvent was removed under reduced pressure to obtain a dry mixture.

[0047] (3) Under a nitrogen atmosphere, pyrolysis was carried out at 650℃ for 1.5 h. Liquid oil was collected with a yield of approximately 25 wt% and a calorific value of 41 MJ / kg. Pyrolysis gas was also collected with a calorific value of approximately 19 MJ / Nm³. 3 .

[0048] (4) The pyrolysis residue was calcined at 850°C for 1.5 h in air atmosphere to obtain porous CaO-Al material.

[0049] Tests show that the specific surface area of ​​the CaO-Al material is 16.3 m². 2 / g, after 20 cycles, the calcium oxide conversion rate remained above 89% of the initial value, which is better than the control material prepared without the plastic template method described in Example 1.

[0050] Example 3 Waste polyethylene plastic was selected as the template agent, calcium nitrate as the calcium source, and manganese acetate as the precursor of the dopant element.

[0051] (1) Weigh polyethylene powder with a particle size of about 250 μm and calcium nitrate at a mass ratio of 10:90. Add the polyethylene powder to carbon tetrachloride solvent and stir at 100°C for 2 hours to allow the polyethylene to partially swell and disperse evenly, forming a modified template agent.

[0052] (2) Mix calcium nitrate and manganese acetate at a molar ratio of 100:8, then mix with the modified template agent and stir for 1.5 h. Then remove the solvent under reduced pressure to obtain a dry mixture.

[0053] (3) Pyrolysis was performed at 550℃ for 1 h under a nitrogen atmosphere. Liquid oil was collected during the pyrolysis process, with a yield of approximately 20 wt% and a higher heating value of approximately 40 MJ / kg; the pyrolysis gas yield was approximately 18 wt%, with a heating value of approximately 20 MJ / Nm³. 3 .

[0054] (4) The pyrolysis residue was calcined at 900°C for 2 h in air atmosphere to obtain a porous CaO-Mn composite material.

[0055] Test results show that the specific surface area of ​​the CaO-Mn composite material is 17.5 m². 2 / g, pore volume 0.26 cm³ 3 / g. After 25 carbonation / calcination cycles, the calcium oxide conversion rate remained above 92% of the initial value, which was significantly better than the undoped and template-free control samples.

[0056] Example 4 Waste polyvinyl chloride plastic was selected as the template agent, calcium hydroxide as the calcium source, and ferric nitrate as the precursor of dopant elements.

[0057] (1) Weigh polyvinyl chloride powder with a particle size of about 150 μm and calcium hydroxide at a mass ratio of 15:85. Add the polyvinyl chloride powder to dichloromethane solvent and stir at 70°C for 2 h to partially dissolve it and form a modified template.

[0058] (2) After mixing calcium hydroxide and ferric nitrate at a molar ratio of 100:12, the mixture was thoroughly mixed with the modified template and stirred for 2 h. Then the solvent was removed under reduced pressure to obtain a dry mixture.

[0059] (3) Pyrolysis was performed at 600℃ for 1.5 h under a nitrogen atmosphere. Liquid oil was collected during the pyrolysis process, with a yield of approximately 28 wt% and a calorific value of approximately 38 MJ / kg; pyrolysis gas was also obtained, with a yield of approximately 16 wt% and a calorific value of approximately 19 MJ / Nm³. 3 .

[0060] (4) The pyrolysis residue was calcined at 850°C for 2 h in air atmosphere to obtain porous CaO-Fe material.

[0061] Performance characterization showed that the specific surface area of ​​the CaO-Fe material was 19.2 m². 2 / g, pore volume 0.30 cm³ 3 / g. In the calcium oxide / calcium carbonate thermochemical cycling experiment, after 20 cycles, the calcium oxide conversion rate remained above 90% of the initial value, indicating excellent cycling stability.

[0062] Example 5 Waste polypropylene plastic was selected as the template agent, calcium carbonate as the calcium source, and ferric nitrate and manganese acetate were added.

[0063] (1) Weigh polypropylene powder with a particle size of about 200 μm and calcium carbonate at a mass ratio of 20:80. Add the polypropylene powder to toluene solvent and stir at 80°C for 2 h to allow the plastic part to swell and form a modified template.

[0064] (2) Calcium carbonate, ferric nitrate and manganese acetate were mixed in an elemental molar ratio of 100:5:5, and then mixed thoroughly with the modified template. The mixture was stirred for 2.5 h, and then the solvent was removed under reduced pressure to obtain a dry mixture.

[0065] (3) Pyrolysis was performed at 600℃ for 2 h under a helium atmosphere. During the pyrolysis process, liquid oil (yield approximately 22 wt%, calorific value approximately 40 MJ / kg) and pyrolysis gas (yield approximately 17 wt%, calorific value approximately 21 MJ / Nm³) were collected. 3 ).

[0066] (4) The pyrolysis residue was calcined at 900°C for 3 h in air atmosphere to obtain a porous CaO-Fe-Mn composite material.

[0067] Tests show that the specific surface area of ​​the CaO-Fe-Mn composite material is 18.8 m². 2 / g, pore volume 0.29 cm³ 3 / g. After 20 calcium oxide / calcium carbonate cycles, the calcium oxide conversion rate remained at 91% of the initial value, and the cycle stability was significantly improved.

[0068] Example 6 Waste methyl methacrylate plastic was selected as the template agent, calcium hydroxide was used as the calcium source, and aluminum nitrate and zirconium nitrate were also doped.

[0069] (1) Weigh polymethyl methacrylate powder with a particle size of about 500 μm and calcium oxide at a mass ratio of 30:70. Add polymethyl methacrylate to acetone solvent and stir at 120℃ for 5 h to obtain modified template.

[0070] (2) Calcium oxide is mixed with aluminum nitrate and zirconium nitrate in an elemental molar ratio of 100:7:8, and then mixed evenly with the modified template. After stirring for 3 h, the solvent is removed under reduced pressure to obtain a dry mixture.

[0071] (3) Under an argon atmosphere, pyrolyze at 750℃ for 0.5 h, and collect liquid oil (yield approximately 24 wt%, calorific value 41 MJ / kg) and pyrolysis gas (yield approximately 16 wt%, calorific value 20 MJ / Nm³). 3 ).

[0072] (4) The pyrolysis residue was calcined at 800°C for 0.5 h in air atmosphere to obtain a porous CaO-Al-Zr composite material.

[0073] Test results show that the specific surface area of ​​the CaO-Al-Zr composite material is 16.9 m². 2 / g, pore volume 0.20 cm³ 3 / g. After 25 cycles of calcium oxide / calcium carbonate, the calcium oxide conversion rate remained at 95% of the initial value, indicating that the composite material with multiple doped elements has good pore structure stability and cycling performance.

[0074] Example 7 Waste polypropylene plastic was selected as the template agent, calcium nitrate as the calcium source, and zirconium nitrate as the precursor for doping elements.

[0075] (1) Weigh polypropylene powder with a particle size of about 150 μm and calcium nitrate at a mass ratio of 15:85. Add the polypropylene powder to acetone solvent and stir at 70°C for 2 h to partially dissolve it and form a modified template.

[0076] (2) After mixing calcium hydroxide and zinc nitrate at a molar ratio of 100:15, the mixture was thoroughly mixed with the modified template and stirred for 1 h. Then the solvent was removed under reduced pressure to obtain a dry mixture.

[0077] (3) Pyrolysis was performed at 650℃ for 1 h under a nitrogen atmosphere. Liquid oil was collected during the pyrolysis process, with a yield of approximately 20.5 wt% and a calorific value of approximately 37 MJ / kg; pyrolysis gas was also obtained, with a yield of approximately 17 wt% and a calorific value of approximately 22 MJ / Nm³. 3 .

[0078] (4) The pyrolysis residue was calcined at 850°C for 2 h in air atmosphere to obtain porous CaO-Zn material.

[0079] Performance characterization showed that the specific surface area of ​​the CaO-Zr material was 19.2 m². 2 / g, pore volume 0.25 cm³ 3 / g. In the calcium oxide / calcium carbonate thermochemical cycling experiment, after 20 cycles, the calcium oxide conversion rate remained above 90% of the initial value, indicating excellent cycling stability.

[0080] Example 8 Waste polystyrene plastic was selected as the template agent, calcium hydroxide as the calcium source, and magnesium nitrate as the precursor for doping elements.

[0081] (1) Weigh polystyrene powder with a particle size of about 200 μm and calcium hydroxide at a mass ratio of 30:70. Add the polystyrene powder to carbon tetrachloride solvent and stir at 80°C for 1 h to partially dissolve it and form a modified template.

[0082] (2) After mixing calcium hydroxide and magnesium acetate at a molar ratio of 100:10, the mixture was thoroughly mixed with the modified template and stirred for 1 h. Then the solvent was removed under reduced pressure to obtain a dry mixture.

[0083] (3) Pyrolysis was performed at 650℃ for 1 h under a nitrogen atmosphere. Liquid oil was collected during the pyrolysis process, with a yield of approximately 24 wt% and a calorific value of approximately 40 MJ / kg; pyrolysis gas was also obtained, with a yield of approximately 16 wt% and a calorific value of approximately 20 MJ / Nm³. 3 .

[0084] (4) The pyrolysis residue was calcined at 850°C for 2 h in air atmosphere to obtain porous CaO-Mg material.

[0085] Performance characterization showed that the specific surface area of ​​the CaO-Zr material was 21.3 m². 2 / g, pore volume 0.30 cm³ 3 / g. In the calcium oxide / calcium carbonate thermochemical cycling experiment, after 20 cycles, the calcium oxide conversion rate remained above 88% of the initial value, indicating excellent cycling stability.

Claims

1. A method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template, characterized in that, The specific steps are as follows: Waste plastic is added to an organic solvent and stirred until the plastic is completely dissolved to obtain a hole-forming template; After mixing the calcium source material with the doped element precursor, a pore-forming template is added and stirred to remove the organic solvent, resulting in a mixture. The mixture was subjected to pyrolysis under an inert atmosphere to obtain volatile products and pyrolysis residues; The pyrolysis residue was calcined at high temperature to obtain a porous calcium-based thermochemical energy storage material with a specific surface area greater than 15 m². 2 / g.

2. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The volatile products are condensed to obtain condensed liquid products and non-condensable gases. The condensed liquid products are liquid oil products, and the non-condensable gases are pyrolysis gases. The yield of the liquid oil products is greater than 20 wt%, with a calorific value greater than 35 MJ / kg, and the yield of the pyrolysis gases is greater than 15 wt%, with a calorific value greater than 18 MJ / Nm³. 3 .

3. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The waste plastic is at least one of polystyrene, polypropylene, polyethylene, polyvinyl chloride, and polymethyl methacrylate, with a particle size of 100–500 μm.

4. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The organic solvent is at least one of carbon tetrachloride, benzene, toluene, acetone, dichloromethane, and carbon tetrachloride.

5. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The calcium source material is at least one of calcium carbonate, calcium hydroxide, calcium oxide, and calcium nitrate.

6. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The mass ratio of waste plastic to calcium source raw material is 10:90 to 30:70, the stirring temperature is 80℃ to 120℃, and the stirring time is 2h to 5h.

7. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The precursors of the doping elements are nitrates or acetates of zinc, magnesium, iron, manganese, aluminum, zirconium, or any combination thereof.

8. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, After mixing the calcium source material with an element molar ratio of 100:(5-15) with the doped element precursor, a pore-forming template is added and the mixture is stirred for 0.5-3 hours. The organic solvent is removed by vacuum distillation or direct evaporation to obtain the mixture.

9. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The pyrolysis heating rate is 100℃ / s to 200℃ / s, the pyrolysis temperature is 500℃ to 700℃, and the holding time is 0.5 h to 2 h; the inert atmosphere is at least one of nitrogen, argon, and helium.

10. The method for preparing porous calcium-based energy storage materials using waste plastic as a pore-forming template according to claim 1, characterized in that, The calcination temperature is 800℃~950℃, and the calcination time is 1h~3h; the calcination atmosphere is at least one of air, oxygen, and carbon dioxide.

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