Method for preparing aromatic hydrocarbon by using metal-loaded biochar
By using a metal-supported biochar catalyst to catalyze the co-pyrolysis of glass fiber epoxy resin and high-density polyethylene, the problems of pollution and resource waste caused by waste materials were solved, achieving efficient production of aromatics, reducing costs and environmental pollution.
Patent Information
- Application Number
- CN202410596748.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-11-14
AI Technical Summary
Waste glass fiber reinforced epoxy resin and high-density polyethylene are difficult to classify and recycle. Traditional treatment methods lead to pollution and waste of resources, and existing technologies are not effective in catalyzing their co-pyrolysis to produce high-value aromatics.
A metal-supported biochar catalyst was used to carry out an in-situ catalytic co-pyrolysis reaction under an inert atmosphere to separate glass fiber and coke, collect high-concentration aromatic pyrolysis oil, and use the metal-supported biochar catalyst to catalyze the co-pyrolysis of glass fiber epoxy resin and high-density polyethylene to prepare aromatics.
This approach increases the value of pyrolysis products, utilizes wood scraps as a resource, reduces costs, achieves more efficient resource utilization of waste plastics, and reduces environmental pollution.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of waste plastic harmless treatment and resource utilization technology, and in particular to a method for preparing aromatics using metal-supported biochar. Background Technology
[0002] Glass fiber reinforced epoxy resin has been widely used in aerospace, daily life, and other fields, greatly facilitating our production and daily life. However, the environmental impact of waste glass fiber reinforced epoxy resin is becoming increasingly serious. Traditional disposal methods such as incineration and landfill cause severe pollution and resource waste. Furthermore, plastic recycling often involves mixing various plastics, making sorting and recycling difficult. To address these issues, we selected high-density polyethylene (HDPE), one of the most common hydrogen-rich plastics, to investigate the effect of co-pyrolysis of glass fiber reinforced epoxy resin with it. We developed a method for preparing aromatics through the co-pyrolysis of glass fiber epoxy resin and HDPE catalyzed by metal-supported biochar. Summary of the Invention
[0003] In view of this, the present invention provides a method for preparing aromatics using metal-supported biochar.
[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0005] A method for preparing aromatics using metal-supported biochar, characterized by comprising the following steps:
[0006] Step 1: Crush the glass fiber reinforced epoxy resin and dry the high-density polyethylene;
[0007] Step 2: Pour the crushed glass fiber reinforced epoxy resin and the dried high-density polyethylene into the first stage reactor respectively;
[0008] Step 3: Place the metal-supported biochar catalyst in the second stage reactor and carry out an in-situ catalytic co-pyrolysis reaction under an inert gas atmosphere;
[0009] Step 4: Solid products remain in the first stage reactor, liquid products are collected by a three-stage cold trap, and gaseous products are collected by a gas bag.
[0010] Step 5: Further processing of the solid product to separate glass fiber from coke.
[0011] Preferably, in step two, the mass ratio of waste glass fiber reinforced epoxy resin to high-density polyethylene is 1 to 8:1, and the two plastics are laid in layers.
[0012] Preferably, in step three, the metal in the metal-supported biochar catalyst is one or both of iron and nickel, wherein the metal loading is 5-20 wt%.
[0013] Preferably, the preparation method of the metal-supported biochar catalyst in step three includes the following steps: biochar and metal salt are mixed in deionized water at a ratio of 5 to 15:1 and impregnated, followed by three steps of stirring, drying and calcination, to obtain the metal-supported biochar catalyst.
[0014] Preferably, the method for preparing the biochar includes the following steps: pine wood and phosphoric acid are mixed in deionized water at a mass ratio of 0.5-4g:1g and then impregnated and activated. After stirring, drying and calcining are carried out to prepare char. The char is then washed with deionized water until neutral and then dried to obtain the biochar.
[0015] Preferably, the impregnation temperature is 70-90°C, the impregnation time is 10-15 h; the drying temperature is 100-120°C, the drying time is 6-12 h; the calcination temperature is 800-900°C, and the calcination time is 1-6 h.
[0016] Preferably, the inert gas in step three is nitrogen or argon, and the gas flow rate is 40-80 mL / min.
[0017] Preferably, the temperature of the catalytic pyrolysis reaction in step three is 500–700°C, and the time is 10–30 min.
[0018] Preferably, in step four, the first, second, and third cold traps in the three-section cold trap are cooled using isopropanol at -70 to -40°C.
[0019] Preferably, the solid product in step four is a mixture of residual carbon and glass fiber, which can be separated into recyclable glass fiber through physical or chemical separation; the liquid product is high-concentration aromatic pyrolysis oil.
[0020] The present invention achieves the following technical effects compared to the prior art:
[0021] (1) The pyrolysis components produced by non-catalytic co-pyrolysis of glass fiber reinforced epoxy resin and high-density polyethylene (HDPE) are phenol and long-chain olefins. However, the present invention uses a metal-supported biochar catalyst to catalyze the co-pyrolysis of glass fiber reinforced epoxy resin and high-density polyethylene (HDPE), and the pyrolysis oil components are mainly aromatic hydrocarbons, which improves the value of the pyrolysis products.
[0022] (2) The metal-supported biochar used in this invention is made from pine wood chips, which not only makes resource use of woodworking scraps, but also catalyzes the co-pyrolysis of epoxy resin and high-density polyethylene (HDPE) to prepare high-value aromatic pyrolysis oil. Moreover, the catalyst can be produced on a large scale in industry, which greatly reduces costs.
[0023] (3) The present invention adopts a rapid pyrolysis method, which shortens the reaction time and realizes more efficient resource utilization of waste plastics. Attached Figure Description
[0024] Figure 1 This is a flowchart of a method for preparing aromatics using metal-supported biochar according to the present invention. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] This invention provides a method for preparing aromatics using metal-supported biochar. The method includes: crushing glass fiber reinforced epoxy resin and pouring it separately into a first-stage reactor along with dried HDPE; placing the metal-supported biochar in a second-stage reactor; and conducting a non-in-situ catalytic co-pyrolysis reaction under an inert gas atmosphere. The solid phase product remains in the first-stage reactor, the liquid phase product is collected by a three-stage cold trap, and the gaseous phase product is collected by a gas bag. The liquid phase product is the high-concentration aromatic pyrolysis oil. Finally, the solid phase product is further processed to separate the glass fiber and coke.
[0027] In this invention, the preparation method of the metal-supported biochar catalyst includes the following steps: biochar and metal salt are mixed in deionized water at a ratio of 5 to 15:1 for impregnation, preferably 8 to 12:1, and in the experiment, it is further preferred to be 10:1. Then, the three steps of impregnation, drying and calcination are performed in sequence to obtain the metal-supported biochar catalyst.
[0028] In this invention, the preparation method of the biochar includes the following steps: pine wood and phosphoric acid are mixed in deionized water at a mass ratio of 0.5 to 4:1 for impregnation and activation, preferably 0.5 to 2:1, and in the experiment, it is further preferred to be 1:1. Then, the biochar is prepared by three steps: stirring, drying and calcining. After that, it is washed with deionized water until neutral, and then dried to obtain the biochar.
[0029] In this invention, the metal in the metal-supported biochar catalyst is one or both of iron and nickel, wherein the metal loading is 5-20 wt%, preferably 8-12 wt%, and more preferably 10 wt% in experiments.
[0030] In this invention, the three-section cold trap is cooled by isopropanol at -65 to -55°C, and preferably at -60°C in the experiment.
[0031] In this invention, the mass ratio of waste glass fiber reinforced epoxy resin to high-density polyethylene (HDPE) is 1 to 8:1, preferably 2 to 6:1, and in the experiment, it is further preferred to be 4:1, with the two plastics laid in layers.
[0032] In this invention, the mass ratio of the waste glass fiber reinforced epoxy resin to the metal-supported biochar catalyst is 1 to 8:1, preferably 2 to 6:1, and in the experiment, it is further preferred to be 4:1.
[0033] In this invention, the inert gas is nitrogen or argon, with nitrogen being preferred in the experiment. The gas flow rate is 40-80 mL / min, preferably 50-70 mL / min, and more preferably 60 mL / min in the experiment.
[0034] In this invention, the temperature of the catalytic pyrolysis reaction is 500–700°C, preferably 550–650°C, and more preferably 600°C in experiments; the time is 5–30 min, preferably 15–25 min, and more preferably 20 min in experiments.
[0035] In this invention, the solid product is a mixture of residual carbon and glass fiber. The mixture can be separated into recyclable glass fiber by physical separation or chemical separation, preferably physical separation, and in the experiment, calcination separation is even more preferred.
[0036] In this invention, the immersion temperature is 70-90°C, preferably 75-85°C, and more preferably 80°C in experiments; the immersion time is 10-15 hours, preferably 11-13 hours, and more preferably 12 hours in experiments.
[0037] In this invention, the drying temperature is 100-120°C, preferably 110°C in experiments, and the drying time is 6-18 hours, preferably 9-15 hours, and even more preferably 12 hours in experiments.
[0038] In this invention, the calcination temperature is 800-900℃, preferably 830-870℃, and more preferably 850℃ in experiments; the calcination time is 1-6h, preferably 2-4h, and more preferably 3h in experiments.
[0039] Example 1:
[0040] 20g of phosphoric acid was dissolved in 250mL of deionized water to obtain a phosphoric acid solution. Then, 20g of pine wood chips were poured into the phosphoric acid solution for impregnation at 80℃. After stirring, drying at 110℃ and calcining at 850℃, the carbon was washed with deionized water until neutral to obtain a biochar catalyst.
[0041] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, followed by 0.5 g of high-density polyethylene (HDPE). The glass fiber epoxy resin and HDPE separated into layers. Then, 0.5 g of biochar catalyst was placed in the second-stage reactor. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0042] Example 2:
[0043] 50g of phosphoric acid was dissolved in 300mL of deionized water to obtain a phosphoric acid solution. Then, 50g of pine wood chips were poured into the phosphoric acid solution for impregnation at 80℃. After stirring, drying at 110℃, and calcining at 850℃, the char was washed with deionized water until neutral to obtain a biochar catalyst.
[0044] 3.61 g of ferric nitrate nonahydrate (FeN3O9·9H2O) was dissolved in 100 mL of deionized water to obtain a ferric nitrate solution. 5 g of the prepared biochar was poured into the ferric nitrate solution and impregnated at 80 °C. After stirring, the solution was dried at 110 °C and calcined at 850 °C to obtain a 10 wt% iron-supported biochar catalyst.
[0045] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, followed by 0.5 g of high-density polyethylene (HDPE). The glass fiber epoxy resin and HDPE separated into layers. Then, 0.5 g of iron-supported biochar catalyst was placed in the second-stage reactor. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was the high-concentration aromatic pyrolysis oil. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0046] Example 3
[0047] 70g of phosphoric acid was dissolved in 500mL of deionized water to obtain a phosphoric acid solution. Then, 70g of pine wood chips were poured into the phosphoric acid solution for impregnation at a temperature of 70℃. After stirring, the solution was dried at 105℃ and calcined at 850℃. After calcination, the carbon was washed with deionized water until neutral to obtain a biochar catalyst.
[0048] 4.93 g of nickel nitrate hexahydrate (NiN2O6·H2O) was dissolved in 50 mL of deionized water to obtain a ferric nitrate solution. 10 g of the prepared biochar was poured into the ferric nitrate solution and impregnated at 70 °C. After stirring, the solution was dried at 105 °C and calcined at 850 °C to obtain a 10 wt% nickel-supported biochar catalyst.
[0049] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, followed by 0.5 g of high-density polyethylene (HDPE). The glass fiber epoxy resin and HDPE separated into layers. Then, 0.5 g of nickel-supported biochar catalyst was placed in the second-stage reactor. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was the high-concentration aromatic pyrolysis oil. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0050] Example 4:
[0051] 60g of phosphoric acid was dissolved in 250mL of deionized water to obtain a phosphoric acid solution. Then, 60g of pine wood chips were poured into the phosphoric acid solution for impregnation at a temperature of 75℃. After stirring, drying at 115℃, and calcining at 850℃, the char was washed with deionized water until neutral to obtain a biochar catalyst.
[0052] 3.61 g of ferric nitrate nonahydrate (FeN3O9·9H2O) and 2.47 g of nickel nitrate hexahydrate (NiN2O6·H2O) were dissolved in 100 mL of deionized water to obtain a ferric nitrate solution. 10 g of the prepared biochar was poured into the ferric nitrate solution and impregnated at 75 °C. After stirring, the solution was dried at 115 °C and calcined at 850 °C to obtain a 5 wt% iron and 5 wt% nickel supported biochar catalyst.
[0053] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, followed by 0.5 g of high-density polyethylene (HDPE). The glass fiber epoxy resin and HDPE separated into layers. Then, 0.5 g of nickel-iron supported biochar catalyst was placed in the second-stage reactor. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was the high-concentration aromatic pyrolysis oil. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0054] Comparative Example 1:
[0055] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, followed by 0.5 g of high-density polyethylene (HDPE). The glass fiber epoxy resin and HDPE separated into layers. Then, 0.5 g of biochar catalyst was placed in the second-stage reactor. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0056] Comparative Example 2:
[0057] Two g of crushed glass fiber epoxy resin was poured into the first-stage reactor, while the second-stage reactor was left empty. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen flow atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gas phase product was collected by a gas bag. The liquid phase product was the high-concentration phenol pyrolysis oil. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0058] Comparative Example 3:
[0059] 0.5 g of high-density polyethylene (HDPE) powder was added to the first-stage reactor, while the second-stage reactor was left empty. An in-situ catalytic pyrolysis reaction was carried out under a nitrogen flow atmosphere of 60 mL / min. The pyrolysis conditions were a rapid catalytic pyrolysis experiment at 600℃ for 20 min. After the pyrolysis reaction, the solid phase product remained in the first-stage reactor, the liquid phase product was collected by a three-stage cold trap, and the gaseous phase product was collected by a gas bag. The liquid phase product was the high-concentration phenol pyrolysis oil. The liquid phase product was detected using GCMS, and the product distribution is shown in Table 1.
[0060] Table 1: Product composition distribution results in high-quality pyrolysis oils obtained from Examples 1-4 and Comparative Examples 1-3
[0061]
[0062] As shown in Table 1, in Comparative Example 2, when epoxy resin was pyrolyzed alone, phenols accounted for 86.97% of the pyrolysis oil products, but phenol accounted for only 37.94%, and the yield of monocyclic and polycyclic aromatic hydrocarbons was low. In Comparative Example 3, when high-density polyethylene (HDPE) was pyrolyzed alone, the products were mainly alkanes and alkenes, with a small amount of aromatics produced by cyclization and isomerization. In Comparative Example 1, when epoxy resin and high-density polyethylene (HDPE) were co-pyrolyzed, all phenols in the products were converted to phenol, with a phenol yield as high as 52.29%. In Example 1, under the condition of using a biochar catalyst, the yield of monocyclic aromatic hydrocarbons could reach 70.03%, and most of the phenol was converted to aromatic hydrocarbons through deoxygenation. In Examples 2-4, under the condition of using a metal-supported biochar catalyst, the total yield of monocyclic aromatic hydrocarbons and phenol increased, with the total yield of monocyclic aromatic hydrocarbons and phenol in the pyrolysis oil obtained by using 10wt% iron-supported biochar catalyst in Example 2 reaching 82.22%. In summary, pyrolysis oil rich in phenol and monocyclic aromatic hydrocarbons can be prepared by catalytic co-pyrolysis of epoxy resin and high-density polyethylene (HDPE) using a 10wt% Fe-supported biochar catalyst. Alternatively, pyrolysis oil rich in aromatic hydrocarbons can be prepared by catalytic co-pyrolysis of epoxy resin and HDPE using a biochar catalyst. Furthermore, co-pyrolysis of epoxy resin and HDPE can convert all phenolic substances in the pyrolysis products of phenol into phenol monomers.
[0063] As shown in the above embodiments, this invention provides a method for preparing aromatics by co-pyrolysis of glass fiber reinforced epoxy resin and HDPE using metal-supported biochar catalyst. Glass fiber reinforced epoxy resin and high-density polyethylene (HDPE) are layered in a first-stage reactor, while the metal-supported biochar catalyst is placed in a second-stage reactor. The reaction is carried out in situ under an inert gas atmosphere, and the collected liquid product is high-concentration phenol pyrolysis oil. The metal-supported biochar catalyst prepared in this invention is sourced from pine sawdust, the most abundant type of wood in my country. This effectively utilizes woodworking scraps while significantly reducing costs. Furthermore, the prepared metal-supported biochar catalyst enhances the aromatic selectivity of the co-pyrolysis of epoxy resin and HDPE, improving the resource utilization efficiency of waste epoxy resin. This invention also provides a method for preparing aromatics by catalytic co-pyrolysis of glass fiber reinforced epoxy resin and hydrogen-rich plastic. The process is simple, and the biochar catalyst can adsorb pollutants, reducing secondary pollution to the environment during production.
[0064] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A method for preparing aromatics using metal-supported biochar, characterized in that, Includes the following steps: Step 1: Crush the glass fiber reinforced epoxy resin and dry the high-density polyethylene; Step 2: Pour the crushed glass fiber reinforced epoxy resin and the dried high-density polyethylene into the first stage reactor respectively; Step 3: Place the metal-supported biochar catalyst in the second stage reactor and carry out an in-situ catalytic co-pyrolysis reaction under an inert gas atmosphere; Step 4: Solid products remain in the first stage reactor, liquid products are collected by a three-stage cold trap, and gaseous products are collected by a gas bag. Step 5: Further processing of the solid product to separate glass fiber from coke.
2. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step two, the mass ratio of waste glass fiber reinforced epoxy resin to high-density polyethylene is 1 to 8:1, and the two plastics are laid in layers.
3. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step three, the metal in the metal-supported biochar catalyst is one or both of iron and nickel, and the metal loading is 5-20 wt%.
4. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, The preparation method of the metal-supported biochar catalyst in step three includes the following steps: biochar and metal salt are mixed in deionized water at a ratio of 5 to 15:1 and impregnated. Then, the three steps of stirring, drying and calcination are carried out in sequence to obtain the metal-supported biochar catalyst.
5. The method for preparing aromatics using metal-supported biochar according to claim 4, characterized in that, The preparation method of the biochar includes the following steps: pine wood and phosphoric acid are mixed in deionized water at a mass ratio of 0.5-4g:1g and then impregnated and activated. After stirring, drying and calcining are carried out to prepare char. Then, the char is washed with deionized water until neutral and then dried to obtain the biochar.
6. A method for preparing aromatics using metal-supported biochar according to any one of claims 4 to 5, characterized in that, The impregnation temperature is 70–90°C, and the impregnation time is 10–15 h; the drying temperature is 100–120°C, and the drying time is 6–12 h; the calcination temperature is 800–900°C, and the calcination time is 1–6 h.
7. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step three, the inert gas is nitrogen or argon, and the gas flow rate is 40-80 mL / min.
8. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step three, the temperature of the catalytic pyrolysis reaction is 500–700°C, and the time is 10–30 min.
9. The method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step four, the first, second, and third sections of the three-section cold trap are cooled using isopropanol at -70 to -40°C.
10. A method for preparing aromatics using metal-supported biochar according to claim 1, characterized in that, In step four, the solid product is a mixture of residual carbon and glass fiber, which can be separated into recyclable glass fiber through physical or chemical separation; the liquid product is high-concentration aromatic pyrolysis oil.