A preparation system and method for preparing graphene based on waste plastic carbonization electric shock

Abstract

The application relates to a preparation system and method for preparing graphene based on waste plastic carbonization electric shock, and relates to the technical field of waste plastic recycling and reuse. The application is used for solving the problems of high motor temperature, large energy consumption and small single reaction amount when waste plastic is converted into graphene. The preparation system comprises a carbonization device, a magnetic conveying belt mechanism, an electric shock device, a fixed bottom plate and a positioning back plate. The fixed bottom plate is horizontally arranged, the positioning back plate is vertically arranged on the rear side of the upper end surface of the fixed bottom plate, the carbonization device is fixedly connected to the upper part of the front end surface of the positioning back plate, the magnetic conveying belt mechanism is arranged below the carbonization device, the discharge end of the carbonization device is arranged at the feeding end of the magnetic conveying belt mechanism, the electric shock device is fixedly connected to the upper end of the fixed bottom plate, and the discharge end of the magnetic conveying belt mechanism is arranged at the feeding end of the electric shock device. The preparation method comprises pretreatment, catalytic carbonization, material separation and magnetization electric shock. The application is used for preparing graphene from waste plastic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste plastic recycling, in particular to a preparation system and method for preparing graphene based on waste plastic carbonization electric shock. BACKGROUND

[0002] "Promote plastic waste recycling and improve the level of harmless disposal of plastic garbage" has become one of the three major tasks of "the 14th Five-Year" plastic pollution control.

[0003] Waste plastics, as a common source of pollution, are difficult to degrade naturally and seriously affect normal production and life of human beings. It takes 1000 years for waste plastics to completely decompose in a landfill. Exploring low-energy and high-value-added recycling methods for waste plastics not only helps to reduce environmental pollution, but also saves resources, which is an important step to achieve the goal of green and sustainable development.

[0004] The existing waste plastic treatment methods mainly include incineration, landfill, mechanical recycling and chemical recycling, as shown in the figure. If landfill treatment method is used, the surface water and groundwater will be seriously polluted; if incineration method is used, harmful substances such as dioxin, polychlorinated biphenyl and furan will be released into the atmosphere. By 2050, China's plastic carbon emissions will reach 2.8 billion tons of carbon dioxide equivalent per year, equivalent to the emissions of 615 power plants of the same size. The carbon emissions of the chemical recycling route of waste plastics are 6.1 tons of CO2 / ton, which is 5.9 tons of CO2 / ton and 2.0 tons of CO2 / ton less than the routes of re-production from coal and oil respectively. Chemical recycling method has become the most commonly used plastic recycling method due to its advantages of product multifunctionalization, high recycling rate and high value material conversion. Figure 2 The common waste plastic recycling products include pyrolysis oil, gaseous alkanes and coke, etc. These products have low economic benefits, and secondary pollution is easy to occur in the recycling process. At present, there is a joule thermal electric flash evaporation technology abroad, which directly breaks the carbon atom bond through joule thermal electric flash evaporation, so as to convert the carbon in waste plastics into graphene. However, the electric shock temperature required by this technology reaches 3000K or more, resulting in high energy consumption and small amount of single reaction, which limits the application and promotion of this technology, and it is still in the laboratory stage at present.

[0005] SUMMARY

[0006] The present application is to solve the problem of high temperature of electric motor required for converting waste plastics into graphene at present, which results in high energy consumption and small amount of single reaction, and further proposes a preparation system and method for preparing graphene based on waste plastic carbonization electric shock.

[0007] The technical scheme adopted by the present application to solve the above technical problems is:

[0008] ​The preparation system for preparing graphene based on waste plastic carbonization electric shock includes a carbonization device, a magnetic conveyor belt mechanism, an electric shock device, a fixed bottom plate, and a positioning back plate. The fixed bottom plate is horizontally arranged. The positioning back plate is vertically arranged on the rear side of the upper end surface of the fixed bottom plate. The carbonization device is fixedly connected to the upper part of the front end surface of the positioning back plate. The magnetic conveyor belt mechanism is arranged below the carbonization device. The discharge end of the carbonization device is arranged at the feeding end of the magnetic conveyor belt mechanism. The electric shock device is fixedly connected to the upper end of the fixed bottom plate. The discharge end of the magnetic conveyor belt mechanism is arranged at the feeding end of the electric shock device.

[0009] Further, the carbonization device includes a heating barrel, a feeding port, an air inlet hole, an air outlet hole, and a receiving hopper. The heating barrel is vertically fixedly connected to the upper part of the front end surface of the positioning back plate. A spiral channel is arranged in the heating barrel along the height direction. The upper end of the heating barrel is provided with a feeding port. An air inlet hole is arranged on one side of the upper end of the heating barrel. The feeding port and the air inlet hole are both connected to the upper end of the spiral channel. The lower end of the heating barrel is provided with a discharge port. An air outlet hole is arranged on one side of the lower end of the heating barrel. The discharge port and the air outlet hole are both connected to the lower end of the spiral channel. A receiving hopper is arranged directly below the discharge port. The lower end of the receiving hopper is arranged directly above the feeding end of the magnetic conveyor belt mechanism.

[0010] Further, the heating barrel is arranged on a fixed frame. The fixed frame is fixedly connected to the front end surface of the positioning back plate through a plurality of corner codes.

[0011] Further, the heating barrel includes an upper barrel cover, a lower barrel cover, and a double-layer barrel body. The upper barrel cover is fixedly connected to the upper part of the double-layer barrel body. The lower barrel cover is fixedly connected to the lower part of the double-layer barrel body. The double-layer barrel body includes an inner layer barrel, an outer layer barrel, a transmission shaft, and a transmission motor. The outer layer barrel is sleeved on the outer side of the inner layer barrel. A heating assembly is arranged between the inner layer barrel and the outer layer barrel. The transmission shaft is vertically inserted into the inner layer barrel. The transmission motor is fixedly connected to the upper barrel cover. The output end of the transmission motor is connected to the upper end of the transmission shaft. A spiral blade is arranged on the outer side wall of the transmission shaft along the length direction. The spiral blade and the inner side wall of the inner layer barrel form a spiral channel.

[0012] Further, a discharge hopper is arranged directly below the discharge end of the magnetic conveyor belt mechanism.

[0013] Further, the electric shock device includes a conductive film, two C-shaped clamps, two electrodes, two pairs of graphite plates, and two clamping mechanisms. The slots of the two C-shaped clamps are fixedly connected to the upper end surface of the fixed bottom plate. The closed ends of the C-shaped clamps are inserted with the electrodes. A pair of graphite plates is horizontally arranged on the lower end side wall in the slot of the C-shaped clamp. The upper end graphite plate is provided with a clamping mechanism above. The end of the electrode abuts against the outer end surface of the graphite plate. The conductive film is horizontally arranged between the two pairs of graphite plates. The end of the conductive film is arranged between the graphite plates on the same side. The discharge end of the discharge hopper is arranged at the middle part of the upper end of the conductive film.

[0014] Further, the clamping mechanism comprises a ceramic bolt and a ceramic nut, the ceramic bolt is vertically inserted in the middle of the upper end side wall of the C-shaped clamp and is threadedly connected with the upper end side wall of the C-shaped clamp, the ceramic nut is fixedly connected with the lower end of the ceramic bolt, and the lower end surface of the ceramic nut is in contact with the upper end surface of the upper end graphite plate.

[0015] A preparation method of graphene prepared based on waste plastic carbonization electric shock comprises the following steps:

[0016] Step one: pretreatment: first, clean the surface of the waste plastic, then classify different types of plastics according to pyrolysis temperature, and then prepare plastic particulate matters by sample fragmentation of the classified plastics;

[0017] Step two: catalytic carbonization: the same type of plastic particulate matters and Fe-Co bimetallic catalyst powder with Al2O3 as the carrier are fully mixed, and then are added into the spiral channel in the heating barrel through the feeding port, nitrogen is then introduced into the closed heating barrel through the air inlet, the air in the heating barrel is discharged through the exhaust port, then the heating barrel starts to heat, the temperature in the heating barrel is gradually increased from room temperature to 800K-1000K, and then is kept constant for two hours, so that the plastic particulate matters in the interior are carbonized into high-purity carbon particles;

[0018] Step three: material separation: the high-purity carbon particles and the Fe-Co bimetallic catalyst powder with Al2O3 as the carrier are discharged from the heating barrel and fall on the magnetic conveying belt mechanism, the Fe-Co bimetallic catalyst powder with Al2O3 as the carrier is adsorbed by the magnetic conveying belt mechanism, and the separated high-purity carbon particles fall on the conductive film;

[0019] Step four: magnetization electric shock: the electrodes are electrified, and the high-purity carbon particles on the conductive film are subjected to electric shock polarization treatment, the high-purity carbon particles are rapidly heated and converted into graphene.

[0020] Further, in step three, the transmission motor is started to drive the transmission shaft to rotate, and the high-purity carbon particles and the Fe-Co bimetallic catalyst powder with Al2O3 as the carrier are discharged from the heating barrel from top to bottom through the discharge port.

[0021] Further, in step four, when the high-purity carbon particles on the conductive film are subjected to electric shock polarization treatment, the climbing current time is 10 milliseconds, the electric shock time is 100 milliseconds, the high-purity carbon particles are heated to 700K-800K, and then are cooled to room temperature.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The application proposes catalytic carbonization technology and magnetization electric shock technology to solve the problem of harsh preparation temperature; introduces Fe-Co bimetallic catalyst with Al2O3 as carrier to improve catalytic conversion efficiency, and finally realizes low energy consumption and high value-added recycling of waste plastics to graphene. The application can realize the following performance indicators:

[0024] 1. The preparation temperature is reduced from 3280K to about 900K, and the energy consumption is reduced by about 3-5 times;

[0025] 2. The product graphene has a graphitization degree of more than 95% after testing;

[0026] 3. The electrochemical test conductivity reaches 6.2S / m.

[0027] When the graphene material produced by the application is used as a battery negative electrode, compared with ordinary batteries sold on the market, the output voltage is more stable, the duration is longer, and the current output is more stable under the condition of charging the same charge capacity. The above can fully illustrate that the graphitization degree of the graphene prepared by the experiment is high, which has met the related market production demand. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the overall structure of the application;

[0029] Figure 2 is a schematic diagram of the structure of the carbonization device in the application;

[0030] Figure 3 is a schematic diagram of the structure of the electric shock device in the application;

[0031] Figure 4 is a flowchart of the conversion of polyethylene to graphene when the recycling process of polyethylene plastic is taken as an example. DETAILED DESCRIPTION

[0032] DETAILED EMBODIMENT ONE: COMBINATION Figures 1 to 3 This embodiment is described, and the preparation system for preparing graphene based on waste plastic carbonization and electric shock includes a carbonization device, a magnetic conveyor belt mechanism 2, an electric shock device, a fixed bottom plate 3 and a positioning back plate 4. The fixed bottom plate 3 is horizontally arranged, the positioning back plate 4 is vertically arranged on the rear side of the upper end surface of the fixed bottom plate 3, the carbonization device is fixedly connected to the upper part of the front end surface of the positioning back plate 4, the magnetic conveyor belt mechanism 2 is arranged below the carbonization device, the discharge end of the carbonization device is arranged at the feeding end of the magnetic conveyor belt mechanism 2, the electric shock device is fixedly connected to the upper end of the fixed bottom plate 3, and the discharge end of the magnetic conveyor belt mechanism 2 is arranged at the feeding end of the electric shock device.

[0033] The pre-processed plastic particles are designed to be carbonized in the carbonization device, and then separated by the magnetic conveying belt mechanism 2, and then enter the electric shock device for magnetization and electric shock into graphene.

[0034] Specific implementation method two: combined Figures 1 to 3 In this embodiment, the carbonization device includes a heating barrel 1, a feeding port 5, an air inlet hole 6, an air outlet hole 7, and a receiving hopper 8. The heating barrel 1 is vertically fixed to the upper part of the front end face of the positioning back plate 4. The heating barrel 1 is provided with a spiral channel 9 in the height direction. The upper end of the heating barrel 1 is provided with a feeding port 5. One side of the upper end of the heating barrel 1 is provided with an air inlet hole 6. The feeding port 5 and the air inlet hole 6 are both connected with the upper end of the spiral channel 9. The lower end of the heating barrel 1 is provided with a discharge port. One side of the lower end of the heating barrel 1 is provided with an air outlet hole 7. The discharge port and the air outlet hole 7 are both connected with the lower end of the spiral channel 9. The receiving hopper 8 is arranged directly below the discharge port. The lower end of the receiving hopper 8 is arranged directly above the feeding end of the magnetic conveying belt mechanism 2. The undisclosed technical features in this embodiment are the same as those in the specific implementation method one.

[0035] The feeding port 5 is used for the entry of materials. After the materials pass through the spiral channel 9, they are discharged through the discharge port. The air inlet hole 6 is used for filling nitrogen into the spiral channel 9. The air outlet hole 7 is used for discharging air in the spiral channel 9.

[0036] Specific implementation method three: combined Figures 1 to 3 In this embodiment, the heating barrel 1 is arranged on the fixed frame 10. The fixed frame 10 is fixed to the front end face of the positioning back plate 4 through a plurality of corner codes 11. The undisclosed technical features in this embodiment are the same as those in the specific implementation method two.

[0037] This design is used to realize the effective positioning of the heating barrel 1.

[0038] Specific implementation method four: combined Figures 1 to 3 In this embodiment, the heating barrel 1 includes an upper barrel cover, a lower barrel cover, and a double-layer barrel body. The upper barrel cover is fixed to the upper part of the double-layer barrel body. The lower barrel cover is fixed to the lower part of the double-layer barrel body. The double-layer barrel body includes an inner barrel, an outer barrel, a transmission shaft, and a transmission motor. The outer barrel is sleeved outside the inner barrel. A heating assembly is arranged between the inner barrel and the outer barrel. The transmission shaft is vertically inserted into the inner barrel. The transmission motor is fixed in the upper barrel cover. The output end of the transmission motor is connected with the upper end of the transmission shaft. A spiral blade is arranged on the outer sidewall of the transmission shaft in the length direction. The spiral blade and the inner sidewall of the inner barrel form a spiral channel 9. The undisclosed technical features in this embodiment are the same as those in the specific implementation method three.

[0039] When the material in the spiral channel 9 needs to be discharged, the transmission motor is turned on to rotate the transmission shaft, and the spiral blades on the transmission shaft push the material to move downward and then be discharged through the discharge port.

[0040] Specific implementation five: combined Figures 1 to 3 In this embodiment, the technical features not disclosed in this embodiment are the same as those in specific implementation one.

[0041] The conveyor belt of the magnetic conveyor belt mechanism 2 is magnetic, and can adsorb the Fe-Co bimetallic catalyst powder with Al2O3 as the carrier on the surface of the conveyor belt, thereby separating it from the mixture, and the unadsorbed plastic particles are collected by the discharge end of the magnetic conveyor belt mechanism 2 into the discharge hopper 12, and the concentrated plastic particles fall onto the conductive film 13 from the discharge end of the discharge hopper 12.

[0042] The magnetic conveyor belt mechanism 2 can use an electromagnet, when the conveyor belt surface adsorbs too much catalyst powder, a receiving plate can be arranged below the magnetic conveyor belt mechanism 2, then the electromagnet is powered off, the catalyst powder loses the magnetic attraction and falls from the conveyor belt to the receiving plate, after cleaning, the electromagnet is powered on and the system operates normally.

[0043] Specific implementation six: combined Figures 1 to 3 In this embodiment, the electric shock device includes a conductive film 13, two C-shaped clamps 14, two electrodes 15, two pairs of graphite plates 16, and two clamping mechanisms. The slots of the two C-shaped clamps 14 are fixed to the upper end surface of the fixed base plate 3, and the closed end of the C-shaped clamp 14 is inserted with the electrode 15. A pair of graphite plates 16 is horizontally arranged on the lower end side wall of the slot of the C-shaped clamp 14, and a clamping mechanism is arranged above the upper end graphite plate 16. The end of the electrode 15 abuts against the outer side surface of the graphite plate 16. The conductive film 13 is horizontally arranged between the two pairs of graphite plates 16, and the end of the conductive film 13 is arranged between the graphite plates 16 on the same side. The discharge end of the discharge hopper 12 is arranged at the middle of the upper end of the conductive film 13. The technical features not disclosed in this embodiment are the same as those in specific implementation five.

[0044] The design of the C-shaped clamp 14 and the two clamping mechanisms realizes the fixation and clamping of the conductive film 13, and the electrode 15 is used to electrify the conductive film 13 to achieve electric shock.

[0045] Specific implementation seven: combined Figures 1 to 3The embodiment is described, the clamping mechanism of the embodiment includes ceramic bolt 17 and ceramic nut 18, ceramic bolt 17 is vertically inserted in the middle of the upper end side wall of C-shaped clamp 14, and is threadedly connected with the upper end side wall of C-shaped clamp 14, ceramic nut 18 is fixedly connected with the lower end of ceramic bolt 17, and the lower end surface of ceramic nut 18 is in contact with the upper end surface of upper end graphite plate 16. The technical features not disclosed in the embodiment are the same as those in embodiment six.

[0046] The design moves the ceramic nut 18 downward to press the graphite plate 16 by rotating the ceramic bolt 17, so that the end of the conductive film 13 is clamped by the two graphite plates 16.

[0047] Embodiment eight: combination Figures 1 to 3 The embodiment is described, the preparation method of graphene based on waste plastic carbonization electric shock includes the following steps:

[0048] Step one: pretreatment: first, clean the surface of the waste plastic, then classify different types of plastics according to pyrolysis temperature, and then prepare plastic particles by fragmentizing the classified samples;

[0049] Step two: catalytic carbonization: mix the same type of plastic particles with Fe-Co bimetallic catalyst powder with Al2O3 as carrier, add them into the spiral channel 9 in the heating barrel 1 from the feeding port, then introduce nitrogen into the closed heating barrel 1 from the air inlet hole 6, and discharge all the air in the heating barrel 1 from the exhaust hole 7, then start heating the heating barrel 1, the temperature in the heating barrel 1 gradually rises from room temperature to 800K-1000K, and then keeps constant temperature for two hours, so that the internal plastic particles are carbonized into high-purity carbon particles;

[0050] Step three: material separation: the high-purity carbon particles and the Fe-Co bimetallic catalyst powder with Al2O3 as carrier are discharged from the heating barrel 1 and fall on the magnetic conveying belt mechanism 2, the Fe-Co bimetallic catalyst powder with Al2O3 as carrier is adsorbed by the magnetic conveying belt mechanism 2, and the separated high-purity carbon particles fall on the conductive film 13;

[0051] Step four: magnetization electric shock: the electrode 15 is electrified, and the high-purity carbon particles on the conductive film 13 are subjected to electric shock polarization treatment, and the high-purity carbon particles are rapidly heated and converted into graphene.

[0052] In step one, the surface of the plastic is cleaned to ensure the normal progress of the reaction; the sample to be decomposed is fragmented to improve the carbonization efficiency and product purity.

[0053] In step two, the ratio of iron to plastic particles in the mixture of plastic particles and Fe-Co bimetallic catalyst powder supported by Al2O3 is 1:1, and the mass fraction of cobalt is 10%.

[0054] In step two, when heating, the temperature in the heating barrel 1 is increased from room temperature at a slow speed to 800K-1000K, and is kept constant for two hours to fully carbonize the plastic particles to produce high-purity carbon particles.

[0055] In the magnetization electric shock device, the purpose of creating a magnetic field environment is to improve product conversion rate and facilitate the preparation of high-purity graphene.

[0056] Specific embodiment nine: combined Figures 1 to 3 In this embodiment, in step three, the motor is turned on to drive the transmission shaft to rotate, and the high-purity carbon particles and Fe-Co bimetallic catalyst powder supported by Al2O3 are discharged from the heating barrel 1 from top to bottom through the discharge port 7. The technical features not disclosed in this embodiment are the same as those in specific embodiment eight.

[0057] Specific embodiment ten: combined Figures 1 to 3 In this embodiment, in step four, when the high-purity carbon particles on the conductive film 13 are subjected to electric shock polarization treatment, the ramp-up current duration is 10 milliseconds, and the electric shock duration is 100 milliseconds. The high-purity carbon particles are heated to 700K-800K, and then cooled to room temperature. The technical features not disclosed in this embodiment are the same as those in specific embodiment eight.

[0058] In a laboratory environment, we only need to undergo two seconds of electric shock polarization treatment (about 10 milliseconds of ramp-up current, and then about 100 milliseconds of electric shock), and the carbon particles are quickly heated to 700K-800K, and then cooled to room temperature within a few seconds. During the discharge process, the carbon particles are quickly heated and rapidly converted into graphene.

[0059] As shown in the following figure, taking the recycling process of polyethylene plastic (PE) as an example: Figure 4

[0060] (1) In the initial pyrolysis, at the same temperature, the reduction degree of C–C bond is greater than that of C–H bond, and the polyethylene molecules are cracked into single —CH2 molecular groups. As the temperature rises, the number of C–C bonds in the whole system rapidly decreases, and the dissociation of carbon chain is basically completed, and the polyethylene molecules are basically cracked into —CH2 molecular groups. Further, the number of C–H bonds begins to decrease rapidly, and the ·H free radicals around the carbon atoms in the —CH2 molecular group gradually separate to become independent carbon atoms; all systems reach the maximum tar yield at about 600K, and the primary cracking is basically completed; thereafter, with the progress of secondary reaction, the tar molecules are further broken down to produce more carbon elemental particles.​

[0061] (2) The carbon particles obtained by carbonization are placed in a magnetic field environment, and the temperature of the carbon particles is raised to about 700K within 10ms through alternating current, under the influence of continuous electric shock and magnetic field, a large pi bond is formed, and the adjacent six carbon atoms form a regular hexagonal structure, and then the multi-layer graphene is generated, and the physical properties are isotropic.

[0062] The present application fully solves the problems of high energy consumption, limited recovery, low product purity and difficulty in meeting industrial production of the Joule heat electric flash evaporation method for preparing graphene, and proposes a new recovery scheme based on carbonization and electric shock "two-step walk".

[0063] According to the market value, about 80000 yuan can be obtained from each kilogram of waste plastics according to the quality of graphene, and about 20000 to 30000 yuan can be obtained from each ton of waste plastics after deducting the energy consumption cost in the preparation process. Compared with traditional graphene, our raw material source is wide, and the energy-saving and emission-reducing purpose of "waste to treasure" is realized. Compared with the Joule heat electric flash evaporation technology, we can reduce energy consumption of more than 1000kWh per kilogram of waste plastics, and the energy-saving benefit is significant.

[0064] In summary, the present application takes the recovery of waste plastics as the starting point and takes graphene products as the end point, which not only provides a new method for waste plastic recovery, but also provides a new idea for the source of new graphene, contributes to energy saving and emission reduction, and improves economic and social benefits.

[0065] The project has remarkable conversion effect under laboratory conditions, and the related parameters are obviously improved compared with the traditional Joule heat flash evaporation method, which can effectively recycle and utilize waste plastics and has practical application value. Theoretically, it can reduce the annual carbon emissions caused by microplastics, and can take into account the environmental and economic benefits, has the potential for large-scale application, and fully embodies the concept of energy saving and emission reduction.

[0066] Although the present application is described herein with reference to particular embodiments, it should be understood that these examples are merely illustrative of the principles and applications of the present application. It should therefore be understood that numerous modifications can be made to the exemplary embodiments, and that other arrangements can be devised without departing from the spirit and scope of the application as defined in the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from the original claims described. It should also be understood that features described in connection with individual embodiments can be used in other described embodiments.

Claims

1. A system for preparing graphene based on carbonization of waste plastics, characterized in that: It includes carbonization device, magnetic conveying belt mechanism (2), electric shock device, fixed bottom plate (3) and positioning back plate (4), the fixed bottom plate (3) is horizontally arranged, the positioning back plate (4) is vertically fixed on the rear side of the upper end surface of the fixed bottom plate (3), the carbonization device is fixed on the upper part of the front end surface of the positioning back plate (4), the magnetic conveying belt mechanism (2) is arranged below the carbonization device, the discharge end of the carbonization device is arranged at the feeding end of the magnetic conveying belt mechanism (2), the electric shock device is fixed on the upper end of the fixed bottom plate (3), and the discharge end of the magnetic conveying belt mechanism (2) is arranged at the feeding end of the electric shock device; The carbonization device includes a heating barrel (1), a feeding port (5), an air inlet hole (6), an air outlet hole (7) and a receiving hopper (8), the heating barrel (1) is vertically fixed on the upper part of the front end surface of the positioning back plate (4), the heating barrel (1) is provided with a spiral channel (9) in the height direction, the upper end of the heating barrel (1) is provided with the feeding port (5), one side of the upper end of the heating barrel (1) is provided with the air inlet hole (6), the feeding port (5) and the air inlet hole (6) are communicated with the upper end of the spiral channel (9), the lower end of the heating barrel (1) is provided with a discharge port, one side of the lower end of the heating barrel (1) is provided with the air outlet hole (7), the discharge port and the air outlet hole (7) are communicated with the lower end of the spiral channel (9), the receiving hopper (8) is arranged directly below the discharge port, and the lower end discharge end of the receiving hopper (8) is arranged directly above the feeding end of the magnetic conveying belt mechanism (2); The magnetic conveying belt mechanism (2) is provided with a discharge hopper (12) directly below the discharge end; The electric shock device includes a conductive film (13), two C-shaped clamps (14), two electrodes (15), two pairs of graphite plates (16) and two clamping mechanisms, the notches of the two C-shaped clamps (14) are fixed on the upper end surface of the fixed bottom plate (3) in opposition, the outer closed end of the C-shaped clamp (14) is inserted with the electrode (15), one pair of graphite plates (16) is horizontally arranged on the lower end side wall in the notch of the C-shaped clamp (14), the clamping mechanism is arranged above the upper graphite plate (16), the end of the electrode (15) abuts against the outer end surface of the graphite plate (16), the conductive film (13) is horizontally arranged between the two pairs of graphite plates (16), the end of the conductive film (13) is arranged between the graphite plates (16) on the same side, and the discharge end of the discharge hopper (12) is arranged at the middle part of the upper end of the conductive film (13).

2. The system for preparing graphene based on waste plastic according to claim 1, wherein: The heating barrel (1) is arranged on the fixed frame (10), and the fixed frame (10) is fixed to the front end surface of the positioning back plate (4) through a plurality of corner codes (11).

3. The system for preparing graphene based on carbonization of waste plastic according to claim 2, characterized in that: The heating barrel (1) comprises an upper barrel cover, a lower barrel cover and a double-layer barrel body, the upper barrel cover is fixedly connected to the upper portion of the double-layer barrel body, the lower barrel cover is fixedly connected to the lower portion of the double-layer barrel body, the double-layer barrel body comprises an inner barrel, an outer barrel, a transmission shaft and a transmission motor, the outer barrel is sleeved outside the inner barrel, a heating assembly is arranged between the inner barrel and the outer barrel, the transmission shaft is vertically inserted into the inner barrel, the transmission motor is fixedly connected to the upper barrel cover, the output end of the transmission motor is connected to the upper end of the transmission shaft, and helical blades are arranged on the outer sidewall of the transmission shaft in the length direction, and the helical blades and the inner sidewall of the inner barrel form a helical channel (9).

4. The system for preparing graphene based on carbonization of waste plastic according to claim 1, wherein: The clamping mechanism comprises a ceramic bolt (17) and a ceramic nut (18), the ceramic bolt (17) is vertically inserted into the middle portion of the upper end sidewall of the C-shaped clamp (14) and is in threaded connection with the upper end sidewall of the C-shaped clamp (14), and the ceramic nut (18) is fixedly connected to the lower end of the ceramic bolt (17) and the lower end surface of the ceramic nut (18) is in contact with the upper end surface of the upper end graphite plate (16).

5. The method of claim 1 to 4, wherein the method comprises: feeding the waste plastic into the carbonization chamber; heating the waste plastic to a temperature of 400-600°C; generating a plasma in the carbonization chamber; and collecting the graphene from the carbonization chamber. The preparation method comprises the following steps: Step one: pretreatment: firstly, the surface of the waste plastic is cleaned, then different types of plastics are classified according to pyrolysis temperature, and then the classified plastics are respectively subjected to sample fragmentation to prepare plastic particulate matter; Step two: catalytic carbonization: the same type of plastic particulate matter is fully mixed with Fe-Co bimetallic catalyst powder taking Al2O3 as a carrier, is added into the helical channel (9) in the heating barrel (1) through a feeding port, then nitrogen is introduced into the closed heating barrel (1) through an air inlet hole (6), the air in the heating barrel (1) is discharged through an air outlet hole (7), then the heating barrel (1) starts to heat, the temperature in the heating barrel (1) is gradually increased from room temperature to 800K-1000K, and then is kept constant for two hours, so that the plastic particulate matter in the heating barrel (1) is carbonized into high-purity carbon particles; Step three: material separation: the high-purity carbon particles and the Fe-Co bimetallic catalyst powder taking Al2O3 as a carrier are discharged from the heating barrel (1) and fall on the magnetic conveying belt mechanism (2), the Fe-Co bimetallic catalyst powder taking Al2O3 as a carrier is adsorbed by the magnetic conveying belt mechanism (2), and the separated high-purity carbon particles fall on the conductive film (13); Step four: magnetization and electric shock: the electrode (15) is electrified, and the high-purity carbon particles on the conductive film (13) are subjected to electric shock polarization treatment, and the high-purity carbon particles are rapidly heated and converted into graphene.

6. The method of claim 5, wherein the method comprises: In step three, the transmission motor is started to drive the transmission shaft to rotate, and the high-purity carbon particles and the Fe-Co bimetallic catalyst powder taking Al2O3 as a carrier are discharged from the heating barrel (1) from top to bottom through the discharge port. ​ 7. The method of claim 5, wherein the method comprises: carbonizing the waste plastic to produce a carbonized product; and applying an electric shock to the carbonized product to produce the graphene. In step four, when the high-purity carbon particles on the conductive film (13) are subjected to electric shock polarization treatment, the climbing current time is 10 milliseconds, the electric shock time is 100 milliseconds, the high-purity carbon particles are heated to 700K-800K, and then are cooled to room temperature.

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