A method for preparing bio-fuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis

Abstract

The application discloses a method for preparing biofuel by low-temperature dechlorination of waste PVC and coupling biomass co-pyrolysis, which comprises the following steps: drying, crushing and screening waste PVC, and then performing low-temperature dechlorination in an inert atmosphere, wherein the carrier gas is inert gas, the dechlorination temperature is 340-380 DEG C, the dechlorination time is 20-40 min, and dechlorinated PVC is obtained; crushing and drying the dechlorinated PVC, and then mixing the dechlorinated PVC with biomass at a mass ratio of 0.1-10:1, and then heating and pyrolyzing at 500-700 DEG C for 20-40 min to obtain biofuel. The method achieves good dechlorination effect through step-by-step pyrolysis, and improves the quality of biofuel; the method has a simple process flow, does not need to add any catalyst and adsorbent, and has a good industrial application prospect.

Description

A method for preparing biofuel from waste PVC by low-temperature dechlorination coupled with biomass co-pyrolysis Technical Field

[0001] This invention belongs to the field of biomass energy and chemicals, specifically relating to a method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Plastics, as a typical fossil fuel product, are widely used in clothing, food packaging, construction, and aerospace due to their excellent corrosion resistance, water resistance, lightweight, and insulation properties. However, the large-scale production, use, and generation of waste plastics have led to severe fossil fuel shortages, environmental pollution, and resource waste. Common waste plastic recycling methods include incineration, landfill, and mechanical modification, but these methods result in serious air pollution, soil and water pollution, complex sorting processes, and low recycling efficiency.

[0004] Biomass, as the only existing carbon-neutral energy source, is widely distributed across various regions. However, as an important component of municipal solid waste, waste biomass (straw, wood chips, agricultural processing by-products, agricultural and forestry waste, and livestock manure, etc.) lacks an efficient and clean recycling method to convert it into usable resources.

[0005] Pyrolysis can effectively realize the resource recycling of municipal solid waste such as waste plastics and waste biomass. Pyrolysis can rapidly decompose waste biomass and waste plastics in an inert atmosphere, thereby producing high-value-added combustible gas, biochar, and biofuel resources. However, due to the high oxygen content of biomass, the resulting biofuel has characteristics such as high acidity, high corrosiveness, high viscosity, and low calorific value, which are not conducive to the utilization of biofuel.

[0006] Waste plastics are essentially high hydrogen-to-carbon ratio polymers, which can act as hydrogen donors in the pyrolysis process of biomass, thereby reducing the oxygen content of bio-oil and improving its quality. Meanwhile, lignocellulosic biomass, whose main components are cellulose, hemicellulose, and lignin, exhibits a synergistic effect with waste plastics in co-pyrolysis, accelerating the decomposition of reactants and increasing the yield of biofuel.

[0007] PVC has a high chlorine content, and waste PVC plastic produces corrosive gases such as HCl during pyrolysis, which reduces the quality and yield of pyrolysis oil. Traditional dechlorination methods, such as mechanochemical dechlorination (co-crushing, co-grinding), hydrothermal dechlorination, adsorbent addition, and catalytic dechlorination, generally suffer from low dechlorination efficiency, complex operation processes, or high costs. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis. This method achieves good dechlorination effect through stepwise pyrolysis and improves the quality of biofuel. The process flow is simple, without the addition of any catalysts or adsorbents, and has good prospects for industrial application.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] A method for preparing biofuel from waste PVC by low-temperature dechlorination coupled with biomass co-pyrolysis includes the following steps:

[0011] Waste PVC is dried, crushed, and screened, and then dechlorinated at low temperature in an inert atmosphere. The carrier gas is an inert gas, the dechlorination temperature is 340-380℃, and the dechlorination time is 20-40 minutes to obtain dechlorinated PVC.

[0012] After dechlorinated PVC is crushed and dried, it is mixed with biomass at a mass ratio of 0.1 to 10:1 and then heated at 500 to 700°C for 20 to 40 minutes to obtain biofuel.

[0013] In some embodiments, the particle size of the waste PVC after crushing and screening is ≤200 mesh.

[0014] In some embodiments, the drying temperature for both waste PVC and dechlorinated PVC is 105–200°C, and the drying time is at least 24 hours.

[0015] In some embodiments, the dechlorination temperature is 350-370℃ and the dechlorination time is 25-35 min.

[0016] Preferably, the dechlorination temperature is 360℃ and the dechlorination time is 30 minutes. The generated HCl gas can be collected and reused.

[0017] Preferably, the heating rate during dechlorination is 10-20℃ / min; more preferably 12-18℃ / min. For example, it can be 15℃ / min.

[0018] In some embodiments, the biomass includes, but is not limited to, rice husks, sawdust, peanut shells, or corn cobs.

[0019] In some embodiments, the biomass further includes steps of washing, crushing, and sieving. Biomass with a particle size smaller than 40 mesh after sieving undergoes secondary drying. This secondary drying is performed to prevent water absorption during crushing, sieving, and subsequent material handling, thus avoiding experimental errors.

[0020] Preferably, the cleaning involves washing the biomass with clean water to remove surface dust and impurities.

[0021] Preferably, the temperature for both stages of biomass drying is 105–200°C, and the drying time is at least 24 hours.

[0022] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0023] (1) By using the stepwise pyrolysis method, the difference between the dechlorination temperature and the thermal decomposition temperature of PVC plastic is utilized to carry out dechlorination in the low-temperature section and achieve a dechlorination efficiency of 99.88% under the dechlorination conditions of 360℃ / 30min, ensuring that the biofuel is basically free of chlorine, thus improving the quality of the biofuel, reducing the risk of corrosion damage to the pyrolysis equipment, and eliminating the need to add adsorbents and catalysts. The operation process is simple, and the HCl gas generated by low-temperature dechlorination can be collected and utilized separately.

[0024] (2) By co-pyrolyzing dechlorinated PVC and biomass, dechlorinated PVC is used as a hydrogen donor to promote stable pyrolysis of biomass and the generation of free radicals. The free radicals generated by biomass further promote the degradation of dechlorinated PVC. The synergistic effect between dechlorinated PVC prepared by the dechlorination method of this invention and biomass greatly promotes the solid-gas conversion rate and oil production efficiency of both. At the same time, the addition of waste dechlorinated PVC reduces the oxygen content of bio-oil and improves the quality of bio-oil. This not only solves the pollution problem caused by the recycling of municipal solid waste such as biomass and waste plastics, but also transforms them into high-value-added products, truly achieving resource recycling. Moreover, the operation process is simple, requiring no catalyst to promote cracking, and has great industrial potential. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] Figure 1 is a process flow diagram of the preparation of biofuel from waste PVC by low-temperature dechlorination coupled with biomass co-pyrolysis provided by the present invention.

[0027] Figure 2 is a schematic diagram of the theoretical and actual values ​​of oil production rate in Embodiments 1 and 2 of the present invention. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The present invention will be further described below with reference to the embodiments.

[0030] Example 1

[0031] The PVC was dried, crushed, and sieved. PVC particles with a particle size ≤200 mesh were placed in a drying oven at 105℃ and dried for 24 hours. The dried PVC particles were then stored in a wide-mouth bottle for later use.

[0032] PVC granules were placed in a reaction pyrolysis furnace. High-purity nitrogen was used as the carrier gas. Nitrogen was first passed through the reactor for 20 minutes at a flow rate of 400 ml / min to create an inert atmosphere. Then, the reactor was heated from room temperature to 360°C at a flow rate of 200 ml / min and a heating rate of 15°C / min. The temperature was maintained for 30 minutes. After that, the device was cooled to room temperature by a cooling fan to obtain solid dechlorinated PVC.

[0033] The dechlorinated PVC was crushed, dried, and sieved. Particles with a diameter ≤80 mesh were placed in a drying oven at 105℃ for 24 hours and stored in a wide-mouth bottle for later use. The sawdust was washed, dried, crushed, and sieved. Particles with a diameter ≤40 mesh were placed in a drying oven at 105℃ for 24 hours and stored in a wide-mouth bottle for later use.

[0034] The treated dechlorinated PVC granules and wood chips were thoroughly mixed by mechanical stirring at a mass ratio of 1:1. The resulting mixture was placed in a pyrolysis reactor. High-purity nitrogen was used as the carrier gas. First, nitrogen was passed through the reactor at a flow rate of 400 ml / min for 20 minutes to create a nitrogen atmosphere. Then, the flow rate was set to 200 ml / min, and the reactor was heated from room temperature to 700°C at a heating rate of 15°C / min. The temperature was maintained for 30 minutes, and then the reactor was cooled to room temperature by a cooling fan.

[0035] The reactants undergo rapid pyrolysis to produce volatile gases. The condensable gases are condensed in a condenser flask, which is then repeatedly washed three times with a carbon disulfide solution to obtain a liquid product. An appropriate amount of sodium sulfate solid is added to the liquid product to remove moisture. The sodium sulfate is removed by filtration. The liquid product is then placed on a hydrocyclone evaporator and evaporated at 50°C for 15 minutes to remove the carbon disulfide solution, yielding biofuel. The non-condensable gases can be collected and reused as combustible fuel. The oil yield in this embodiment was calculated to be 40.1% by weighing. The obtained solid was dried in a 105°C drying oven for 24 hours, and the solid mass was weighed. The conversion rate from solid to volatile matter was calculated to be 75.17%.

[0036] Example 2

[0037] Waste PVC was dried, crushed, and sieved. Waste PVC particles with a particle size ≤200 mesh were placed in a drying oven at 150℃ for 30 hours and then stored in a wide-mouth bottle for later use.

[0038] Waste PVC granules are placed in a reaction pyrolysis furnace. High-purity nitrogen is used as the carrier gas. Nitrogen is first passed through the reactor for 30 minutes at a flow rate of 400 ml / min to create an inert atmosphere. Then, the reactor is heated from room temperature to 360°C at a flow rate of 200 ml / min and a heating rate of 15°C / min, and held for 30 minutes. After that, the device is cooled to room temperature by a cooling fan to obtain solid dechlorinated waste PVC.

[0039] The dechlorinated waste PVC was crushed, dried, and sieved. Particles with a particle size ≤80 mesh were placed in a drying oven at 150℃ for 30 hours and stored in a wide-mouth bottle for later use. The sawdust was washed, dried, crushed, and sieved. Particles with a particle size ≤40 mesh were placed in a drying oven at 150℃ for 30 hours and stored in a wide-mouth bottle for later use.

[0040] The treated wood chips and dechlorinated waste PVC particles were thoroughly mixed by mechanical stirring at a mass ratio of 1:2.3. The resulting mixture was placed in a pyrolysis reactor. High-purity nitrogen was used as the carrier gas. First, nitrogen was passed through the reactor at a flow rate of 400 ml / min for 30 minutes to form a nitrogen atmosphere. Then, the flow rate was set to 200 ml / min, and the reactor was heated from room temperature to 500°C at a heating rate of 15°C / min. The temperature was maintained for 30 minutes, and then the reactor was cooled to room temperature by a cooling fan.

[0041] The reactants undergo rapid pyrolysis to produce volatile gases, among which condensable gases are condensed in a condenser flask. The condenser flask is repeatedly washed three times with carbon disulfide solution to obtain a liquid product. An appropriate amount of sodium sulfate solid is added to the obtained liquid product to absorb moisture. The sodium sulfate is removed by filtration. Subsequently, the liquid product is placed on a hydrocyclone evaporator and evaporated at 50°C for 15 minutes to remove the carbon disulfide solution, yielding biofuel. The oil yield in this example is calculated by weighing. The obtained solid is dried in a 105°C drying oven for 24 hours, and the solid mass is weighed to calculate the conversion rate of the solid to volatiles. In this case, the oil yield is 45.67%, and the conversion rate of the solid to volatiles is 68.67%.

[0042] Example 3

[0043] Waste PVC was dried, crushed, and sieved. Waste PVC particles with a particle size ≤200 mesh were placed in a drying oven at 200℃ for 24 hours and then stored in a wide-mouth bottle for later use.

[0044] Waste PVC granules are placed in a reaction pyrolysis furnace. High-purity nitrogen is used as the carrier gas. Nitrogen is first passed through the reactor at a flow rate of 400 ml / min for 40 min to create an inert atmosphere. Then, the reactor is heated from room temperature to 360°C at a flow rate of 200 ml / min and a heating rate of 15°C / min, and held for 30 min. After that, the device is cooled to room temperature by a cooling fan to obtain solid dechlorinated waste PVC.

[0045] The dechlorinated waste PVC was crushed, dried, and sieved. Particles with a particle size ≤80 mesh were placed in a drying oven at 200℃ for 24 hours and stored in wide-mouth bottles for later use. Corn cobs and rice husks were washed, dried, crushed, and sieved. Particles with a particle size ≤40 mesh were placed in a drying oven at 200℃ for 24 hours and stored in wide-mouth bottles for later use.

[0046] The treated dechlorinated waste PVC granules were thoroughly mixed with corn cob granules and rice husk granules at mass ratios of 1:4 and 1:9 respectively using mechanical stirring. The resulting mixture was then placed in a pyrolysis reactor. High-purity nitrogen was used as the carrier gas. First, nitrogen was passed through the reactor at a flow rate of 400 ml / min for 30 minutes to create a nitrogen atmosphere. Then, the flow rate was set to 200 ml / min, and the reactor was heated from room temperature to 500°C at a heating rate of 15°C / min. The temperature was maintained for 30 minutes, and then the reactor was cooled to room temperature using a cooling fan.

[0047] The reactants undergo rapid pyrolysis to produce volatile gases, among which condensable gases are condensed in a condenser flask. The condenser flask is repeatedly washed three times with carbon disulfide solution to obtain a liquid product. An appropriate amount of sodium sulfate solid is added to the obtained liquid product to absorb moisture. The sodium sulfate is removed by filtration. Subsequently, the liquid product is placed on a hydrocyclone evaporator and evaporated at 50°C for 15 minutes to remove the carbon disulfide solution, yielding biofuel. The oil yield in this embodiment is calculated by weighing. The obtained solid is dried in a 200°C drying oven for 24 hours, and the solid mass is weighed to calculate the conversion rate of solid to volatiles. In this case, the oil yield is 41.58% when corn cob pellets and dechlorinated waste PVC pellets are in a 1:4 ratio, and the conversion rate of solid to volatiles is 68.67%. When rice husk pellets and dechlorinated waste PVC pellets are in a 1:9 ratio, the oil yield is 44.73%, and the conversion rate of solid to volatiles is 68.56%.

[0048] Example 4

[0049] Waste PVC mixed plastics were dried, crushed, and screened. Waste PVC mixed plastic particles with a particle size ≤200 mesh were placed in a drying oven at 110℃ and dried for 30 hours. The dried waste PVC mixed plastic particles were then stored in a wide-mouth bottle for later use.

[0050] Waste PVC mixed plastic granules were placed in a reaction pyrolysis furnace. High-purity nitrogen was used as the carrier gas. Nitrogen was first passed through the reactor for 40 minutes at a flow rate of 400 ml / min to create an inert atmosphere. Then, the reactor was heated from room temperature to 360°C at a flow rate of 200 ml / min and a heating rate of 15°C / min and held for 30 minutes. After that, the device was cooled to room temperature by a cooling fan to obtain solid dechlorinated waste PVC mixed plastic.

[0051] The dechlorinated waste PVC mixed plastic was crushed, dried, and sieved. The dechlorinated waste PVC mixed particles with a particle size ≤80 mesh were placed in a drying oven at 110℃ and dried for 30 hours. The dried dechlorinated waste PVC mixed plastic particles were then stored in a wide-mouth bottle for later use.

[0052] The sawdust, corn cobs, and peanut shells were washed, dried, crushed, and sieved. Particles with a particle size ≤40 mesh were placed in a drying oven at 110℃ for 30 hours. The dried sawdust and corn cobs and sawdust and peanut shells were then thoroughly mixed by mechanical stirring at a mass ratio of 1:1 to obtain sawdust-corn cob mixed particles and sawdust-peanut shell mixed particles. The processed mixed biomass particles were stored in wide-mouth bottles for later use.

[0053] The treated sawdust-corncob mixture and sawdust-peanut shell mixture were thoroughly mixed with dechlorinated waste PVC plastic at mass ratios of 1:8 and 1:10 respectively using mechanical stirring. The resulting mixture was then placed in a pyrolysis reactor. High-purity nitrogen was used as the carrier gas. The reactor was first purged with nitrogen at a flow rate of 400 ml / min for 40 minutes to create a nitrogen atmosphere. The flow rate was then set to 200 ml / min, and the reactor was heated from room temperature to 500°C at a heating rate of 15°C / min. The temperature was maintained for 30 minutes, and then the reactor was cooled to room temperature using a cooling fan.

[0054] The reactants undergo rapid pyrolysis to produce volatile gases, among which condensable gases are condensed in a condenser flask. The condenser flask is repeatedly washed three times with carbon disulfide solution to obtain a liquid product. An appropriate amount of sodium sulfate solid is added to the obtained liquid product to absorb moisture. The sodium sulfate is removed by filtration. Subsequently, the liquid product is placed on a hydrocyclone evaporator and evaporated at 50°C for 15 minutes to remove the carbon disulfide solution, yielding biofuel. The oil yield of this embodiment is calculated by weighing. The obtained solid is dried in a 110°C drying oven for 30 hours, and the mass of the solid is weighed to calculate the conversion rate of the solid to volatiles.

[0055] In this case, when the ratio of sawdust and corn cob mixed pellets to dechlorinated waste PVC mixed plastic was 1:8, the oil yield was 41.36%, and the conversion rate of solids to volatiles was 67.83%. When the ratio of sawdust and peanut shell mixed pellets to dechlorinated waste PVC mixed plastic was 1:10, the oil yield was 40.39%, and the conversion rate of solids to volatiles was 67.88%.

[0056] Comparative Example 1

[0057] The difference from Example 4 is that the waste PVC dechlorination method in Example 4 is replaced with co-grinding dechlorination with calcium oxide. Before the pyrolysis experiment, waste PVC and calcium oxide in a mass ratio of 1:10 are placed in a ball mill. The ball mill speed is set to 400 r / min, and the mixture is ground for 30 min. After grinding, the ball mill is cooled to room temperature for 1 h. The sample is then removed, sieved, washed with deionized water, filtered, and dried for subsequent experiments. All other steps are the same as in Example 4.

[0058] When the ratio of sawdust and corn cob mixed pellets to dechlorinated waste PVC mixed plastic is 1:8, the oil yield is 28.37%, and the conversion rate of solids to volatiles is 53.21%. When the ratio of sawdust and peanut shell mixed pellets to dechlorinated waste PVC mixed plastic is 1:10, the oil yield is 30.13%, and the conversion rate of solids to volatiles is 54.63%.

[0059] Comparative Example 2

[0060] The difference from Example 4 is that the waste PVC dechlorination method in Example 4 is replaced with alkaline hydrothermal dechlorination. Before the pyrolysis experiment, the waste PVC is thoroughly mixed with a 1 mol / L NaOH solution and transferred to a high-pressure reactor. The reactor is heated to 260°C at a rate of 10°C / min and maintained for 90 min. After the reaction, the reactor is naturally cooled to ambient temperature with air. The material is then removed and filtered through a 0.45 μm filter membrane to remove water and carbon, and washed with deionized water to remove surface Cl. - The samples were then dried in an oven at 105°C for 24 hours and then used for subsequent experiments. All other steps were the same as in Example 4.

[0061] When the ratio of sawdust and corn cob mixed pellets to dechlorinated waste PVC mixed plastic is 1:8, the oil yield is 36.89%, and the conversion rate of solids to volatiles is 58.47%. When the ratio of sawdust and peanut shell mixed pellets to dechlorinated waste PVC mixed plastic is 1:10, the oil yield is 37.24%, and the conversion rate of solids to volatiles is 61.34%.

[0062] The composition and proportion of biofuels obtained in Examples 1 and 2 and pure wood biomass fuels were detected by GC-MS technology. The detection results of pure wood biomass are shown in Table 1, and the detection results of biofuels obtained in Examples 1 and 2 are shown in Table 2. The theoretical and actual values ​​of oil yield in Examples 1 and 2 are shown in Figure 2.

[0063] Table 1

[0064]

[0065]

[0066] Table 2

[0067]

[0068]

[0069] Table 1 shows that biomass pyrolysis oil contains high acidity, with acetic acid accounting for 45.74%, which is the reason for its high corrosivity. Simultaneously, the oxygen content is as high as 98.09%, resulting in a low calorific value and low quality. Table 2 shows that the bio-oil produced by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis has significantly reduced acidity and contains aliphatic and aromatic hydrocarbons such as propane, 2-hexene, p-xylene, and 1,2,3-trimethylbenzene. This reduces the oxygen content of the bio-oil and improves the quality of the biofuel.

[0070] As shown in Figure 2, compared with the theoretical value, co-pyrolysis improved the yield of biofuel and increased the oil production efficiency. Examples 1-4 demonstrate that the low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis to produce biofuel not only solves the problems of corrosion of machinery and equipment and low quality of biofuel caused by the high chlorine content of PVC plastics, but also converts Cl into reusable HCl resources. Furthermore, it reduces the acidity and oxygen content in the biofuel, improving its quality. It also boasts a high oil yield (35%–50%) and solid-gas conversion rate (65%–80%), further increasing biofuel production. Moreover, the process is simple, requiring no catalysts or adsorbents, truly achieving clean and efficient resource recycling of agricultural, forestry, and industrial organic solid waste.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing biofuel from waste PVC through low-temperature dechlorination coupled with biomass co-pyrolysis, characterized in that: The process includes the following steps: Waste PVC is dried, crushed, and screened, then dechlorinated at low temperature in an inert atmosphere. The carrier gas is an inert gas, the dechlorination temperature is 350-370℃, and the dechlorination time is 25-35 minutes, yielding dechlorinated PVC. The dechlorinated PVC is then crushed and dried, mixed with biomass at a mass ratio of 0.1-10:1, and heated at 500-700℃ for 20-40 minutes to obtain biofuel. The oil yield is 35%-50%, and the solid-to-gas conversion rate is 65%-80%. The HCl gas produced during low-temperature dechlorination is collected and utilized separately. The addition of waste dechlorinated PVC reduces the oxygen content of the biofuel and improves its quality.

2. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with co-pyrolysis of biomass according to claim 1, characterized in that: The particle size of waste PVC after crushing and screening is ≤200 mesh.

3. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with co-pyrolysis of biomass according to claim 1, characterized in that: The drying temperature for both waste PVC and dechlorinated PVC is 105~200℃, and the drying time is at least 24 hours.

4. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with co-pyrolysis of biomass according to claim 1, characterized in that: The dechlorination temperature was 360℃ and the dechlorination time was 30 minutes.

5. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis according to claim 1, characterized in that: During dechlorination, the heating rate is 10-20℃ / min.

6. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis according to claim 5, characterized in that: During dechlorination, the heating rate is 12-18℃ / min.

7. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis according to claim 1, characterized in that: The biomass is one or more of rice husks, sawdust, peanut shells, or corn cobs.

8. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis according to claim 1, characterized in that: The biomass also includes steps of washing, drying, crushing and sieving, and the biomass with a particle size of less than 40 mesh after sieving is subjected to secondary drying.

9. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with biomass co-pyrolysis according to claim 8, characterized in that: The cleaning process involves washing the biomass with clean water to remove surface dirt and impurities.

10. The method for preparing biofuel by low-temperature dechlorination of waste PVC coupled with co-pyrolysis of biomass according to claim 8, characterized in that: The temperature for both stages of biomass drying is 105~200℃, and the drying time for each stage is at least 24 hours.

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