A method and system for preparing graphene based on natural gas containing carbon dioxide

Abstract

The present invention relates to a graphene preparation method and system based on carbon dioxide-containing natural gas in the field of graphene preparation technology, comprising the following steps: raw material preparation and pretreatment, including filtering and drying natural gas to remove solid particles and moisture. Gas separation, first using a membrane separation device to separate carbon dioxide and hydrocarbons, then removing impurities through a condensation and desulfurization device, and finally mixing and adjusting the gas ratio to meet the graphene preparation requirements; natural gas cracking to prepare graphene, cracking reaction at high temperature to generate graphene and tail gas; tail gas treatment and recovery, initial filtration to remove particulate matter, heat exchange to recover tail gas heat, separation of gas after filtration to recover hydrogen and carbon dioxide, hydrogen is used to heat the cracking furnace, and carbon dioxide is further processed to save energy; product collection and purification, cooling the graphene to a set temperature, collecting and purifying to remove residual impurities, realizing the integration of efficient energy utilization and tail gas purification, and improving the utilization rate of raw materials and energy.

Description

Technical Field

[0001] The present invention relates to a graphene preparation method, and in particular to a graphene preparation method and system based on carbon dioxide-containing natural gas, which are applied in the field of graphene preparation technology. Background Art

[0002] Graphene, a two-dimensional material consisting of a single layer of carbon atoms arranged in a hexagonal pattern, has attracted much attention due to its remarkable electrical, thermal, and mechanical properties.

[0003] Natural gas has relatively abundant reserves worldwide and is an important source of energy with a relatively stable supply and controllable costs to a certain extent. Although the composition of natural gas containing carbon dioxide is relatively complex, it is also characterized by large quantity and strong accessibility, which provides a sufficient raw material basis for large-scale graphene preparation and ensures sustained and stable production.

[0004] Traditional natural gas cracking technology has been developed to a certain extent in the chemical industry, for example, it is used to prepare synthesis gas and other related products. These existing cracking technologies, processes and related equipment provide technical references and basic conditions for the production of graphene by cracking natural gas containing carbon dioxide. Researchers can make improvements and innovations on this basis, explore specific cracking process parameters, reaction conditions and supporting catalytic systems suitable for graphene preparation, so as to achieve efficient graphene production.

[0005] The Chinese invention patent CN116462191B specification discloses a method for preparing graphene, comprising: a) mixing a graphite raw material with an intercalation agent, and allowing to stand to obtain a colloidal dispersion; b) filtering the colloidal dispersion, and drying the filtrate to obtain modified solid graphite; c) expanding the modified solid graphite in a microwave field to obtain graphene. The application pours the graphite raw material that has been fully pretreated above into a high-power continuous microwave system, and by monitoring and controlling the microwave power and temperature, realizes rapid dry microwave expansion in the air, thereby directly obtaining a defect-free, ton-level graphene product.

[0006] The Chinese invention patent CN118419917B specification discloses a graphene, graphene film and preparation method thereof reduced by graphene oxide. The method comprises the following steps: dispersing graphene oxide in a mixed solution of triethylene glycol to form a graphene oxide dispersion, irradiating with a laser wavelength of 1000-1100nm, washing and drying to obtain graphene after the irradiation; the invention combines a laser with a wavelength of 1064nm with a dispersion based on triethylene glycol, which can provide extremely high transient energy for the reactants, thereby promoting the deprotonation process and the reduction process, and the prepared graphene is completely reduced, with a large size and few defects.

[0007] Existing graphene preparation methods still face problems such as high energy consumption and complex tail gas treatment; and it is not easy to recycle and treat the scattered natural gas containing high concentrations of CO2. How to efficiently recycle and utilize tail gas, reduce energy consumption, and achieve green preparation has become a bottleneck that urgently needs to be broken through in the field of graphene. Summary of the invention

[0008] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the existing graphene preparation method still faces problems such as high energy consumption and complex tail gas treatment; and it is not easy to recycle and treat the discharged scattered natural gas containing high concentrations of CO2; how to efficiently recycle and utilize tail gas, reduce energy consumption, and achieve green preparation has become a bottleneck that urgently needs to be broken through in the field of graphene.

[0009] In order to solve the above problems, the present invention provides a method for preparing graphene based on natural gas containing carbon dioxide, which specifically comprises the following steps:

[0010] A1: Preparation and pretreatment of raw materials; During the pretreatment stage, natural gas is filtered and dried to remove solid particle impurities and moisture;

[0011] A2: Gas separation: First, the carbon dioxide and hydrocarbons in the natural gas are separated by a membrane separation device to obtain carbon dioxide-enriched gas and purified natural gas;

[0012] The carbon dioxide-enriched gas is then dehydrated by a condensation dehydration device; and the sulfide impurities in the carbon dioxide-enriched gas are removed by a desulfurization device;

[0013] Finally, the purified natural gas is mixed with the carbon dioxide-enriched gas according to demand, and the composition ratio of the gas is adjusted to meet the requirements for graphene preparation;

[0014] A3: Preparation of graphene by cracking natural gas: In the preparation stage of the molten cracking furnace, the purified natural gas and the carbon dioxide-enriched gas mixture are introduced into the molten cracking furnace; the natural gas cracking reaction is carried out at a high temperature of 800 to 1000 degrees Celsius to promote the decomposition of natural gas to produce graphene; the tail gas generated by the reaction includes: particulate matter, hydrogen, carbon dioxide and a small amount of methane; the particulate matter includes: carbon black and catalyst particles;

[0015] A4: Tail gas treatment and recovery: The tail gas discharged from the molten cracking furnace is initially filtered through a filtering treatment device to remove particulate matter in the tail gas, and the heat of the tail gas is recovered through heat exchange between the inert gas and the tail gas during the filtering process; the inert gas after heat exchange is used to assist graphene cooling;

[0016] After filtration, the tail gas is subjected to gas separation treatment by tail gas separation equipment to recover hydrogen and carbon dioxide in the tail gas; the recovered hydrogen is mixed with natural gas and used for heating the cracking furnace in A3;

[0017] The recovered CO2 is mixed with the CO2-enriched gas before dehydration in A2 for further processing to reduce energy consumption;

[0018] A5: Product collection and purification: The graphene in the molten cracking furnace is cooled in sections to the set temperature, and then the generated graphene is collected and purified to completely remove the residual catalyst and other impurities.

[0019] In the above-mentioned graphene preparation method based on natural gas containing carbon dioxide, efficient energy utilization and exhaust gas purification are integrated, environmental pollution is reduced, the utilization rate of raw materials and energy is improved, and the overall process flow is optimized.

[0020] As a further improvement of the present application, the filtering treatment device includes a shell, the two ends of the shell are respectively connected to an input pipe and an output pipe, an air supply pipe is passed through the shell, the air supply pipe includes a guide pipe, the top of the guide pipe is fixedly connected to a diversion filter ring, a porous filter block is sleeved on the air supply pipe, and the top of the shell is detachably connected to an insulation cover matching the porous filter block, a heat exchange tube group is passed through the insulation cover, the heat exchange tube group includes a heat exchange tube row located in the insulation cover, the heat exchange tube row is inserted into the porous filter block and is arranged around the diversion filter ring, and the input end and output end of the heat exchange tube row are respectively connected to the air inlet pipe and the air outlet pipe.

[0021] As a further improvement of the present application, the top end of the thermal insulation cover is fixedly connected to a voltage-stabilizing assembly, the voltage-stabilizing assembly includes a pressure-increasing device, a compression spring is sleeved on the outer side of the movable end of the pressure-increasing device, a sealing block is inserted into the top end of the diverter filter ring, a pressure sensor is installed on the top end of the compression spring, and a retaining ring matching the sealing block is fixedly connected to the lower end of the compression spring, a sealing sleeve covering the compression spring is connected between the top end of the diverter filter ring and the thermal insulation cover, and a brush layer is laid on the side wall of the sealing block at one end inside the diverter filter ring.

[0022] As a further improvement of the present application, an ash unloading mechanism is connected between the bottom end of the guide pipe and the input pipe, and the ash unloading mechanism includes a three-way pipe, and an ash unloading valve is fixedly connected to the lower output end of the three-way pipe; an opening and closing valve is connected to the side input end of the three-way pipe.

[0023] As another improvement of the present application, the tail gas separation equipment includes a first membrane separation device and a hydrogen purification device, the first membrane separation device is used to separate the hydrogen-rich gas; the hydrogen purification device is used to separate carbon dioxide and hydrogen from the hydrogen-rich gas.

[0024] As another improved supplement of the present application, the side gas output ends of the first membrane separation device and the hydrogen purification device are both installed with temperature sensors; the hydrogen purification device is connected to a carbon dioxide output pipe, on which a temperature sensor is installed; and a cooling pipe is wound around the carbon dioxide output pipe.

[0025] A graphene preparation system based on natural gas containing carbon dioxide includes a processor, to which a control module, a monitoring module, a data processing module and a data storage module are connected;

[0026] A control module for adjusting the use of recycled gas and the utilization of recycled heat;

[0027] The monitoring module collects monitoring data, including: the amount of recovered gas and heat recovery fluid;

[0028] The data processing module is used to analyze monitoring data and optimize cracking parameters; the data storage module records the data of the entire process.

[0029] In summary, this solution achieves efficient utilization of natural gas resources containing carbon dioxide and maximizes the utilization of resources; through precise monitoring, data processing and regulation, it ensures the stability and controllability of the graphene preparation process and improves the quality and output of the product; the exhaust gas generated during the preparation process is effectively treated to reduce environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a method flow chart of the first implementation mode of this application;

[0031] Figure 2 This is a topological diagram of the first implementation mode of this application;

[0032] Figure 3 This is a three-dimensional diagram of a filtering treatment device according to the first embodiment of the present application;

[0033] Figure 4 This is a cross-sectional view of a filtering treatment device according to the first embodiment of the present application;

[0034] Figure 5 This is a working schematic diagram of the filtering treatment device according to the first embodiment of the present application;

[0035] Figure 6 This is a working schematic diagram of the tail gas separation device of the first embodiment of the present application;

[0036] Figure 7 This is a system block diagram of the second implementation mode of this application.

[0037] Description of the numbers in the figure:

[0038] 1. Shell; 2. Gas transmission pipe; 21. Flow guide pipe; 22. Diverter filter ring; 3. Porous filter block; 4. Heat insulation cover; 5. Heat exchange tube group; 51. Heat exchange tube row; 52. Inlet pipe; 53. Outlet pipe; 6. Voltage stabilizing assembly; 61. Pressurizing device; 62. Compression spring; 63. Sealing block; 7. Ash unloading mechanism; 8. First membrane separation device; 9. Hydrogen purification device. DETAILED DESCRIPTION

[0039] The following describes two implementation modes of the present application in detail with reference to the accompanying drawings.

[0040] The first implementation method:

[0041] Figure 1-6 A method for preparing graphene based on natural gas containing carbon dioxide is shown, which specifically comprises the following steps:

[0042] A1: Preparation and pretreatment of raw materials; During the pretreatment stage, natural gas is filtered and dried to remove solid particle impurities and moisture;

[0043] A2: Gas separation: First, the carbon dioxide and hydrocarbons in the natural gas are separated by a membrane separation device to obtain carbon dioxide-enriched gas and purified natural gas; the separated carbon dioxide-enriched gas and natural gas are stored in gas tanks for standby use;

[0044] Then the carbon dioxide-enriched gas is dehydrated by a condensation dehydration device; and the sulfide impurities in the carbon dioxide-enriched gas are removed by a desulfurization device. In this scheme, the condensation dehydration device and desulfurization device in the prior art are used to dehydrate and desulfurize the carbon dioxide. The technicians in this field use appropriate dehydration and desulfurization devices to set them up, and they will not be described in detail in this scheme.

[0045] Finally, the purified natural gas is mixed with the carbon dioxide-enriched gas according to demand. During the mixing, the gas is distributed by a mixed gas distribution device in the prior art to adjust the composition ratio of the gas to meet the graphene preparation requirements;

[0046] A3: Preparation of graphene by cracking natural gas: In the preparation stage of the molten cracking furnace, the purified natural gas and the carbon dioxide-enriched gas mixture are introduced into the molten cracking furnace; the natural gas cracking reaction is carried out at a high temperature of 800 to 1000 degrees Celsius to promote the decomposition of natural gas to produce graphene; the tail gas generated by the reaction includes: particulate matter, hydrogen, carbon dioxide and a small amount of methane; the particulate matter includes: carbon black and catalyst particles;

[0047] A4: Tail gas treatment and recovery: The tail gas discharged from the molten cracking furnace is initially filtered through a filtering treatment device to remove particulate matter in the tail gas, and the heat of the tail gas is recovered through heat exchange between the inert gas and the tail gas during the filtering process; the inert gas after heat exchange is used to assist graphene cooling;

[0048] After the inert gas is heat exchanged, the inert gas is stored in batches and the temperature is monitored, and according to the stable temperature of the inert gas after the heat exchange, the temperature-stable inert gas is used for a suitable cooling stage of the graphene;

[0049] After filtration, the tail gas is subjected to gas separation treatment by tail gas separation equipment to recover hydrogen and carbon dioxide in the tail gas; the recovered hydrogen is mixed with natural gas and used for heating the cracking furnace in A3;

[0050] The recovered CO2 is mixed with the CO2-enriched gas before dehydration in A2 for further processing to reduce energy consumption;

[0051] A5: Product collection and purification; cool the graphene in the molten cracking furnace to the set temperature in sections. During the section cooling, use gas streams of different temperatures to exchange heat with the graphene in stages. At the same time, according to the temperature of the inert gas for recovering the waste heat of the tail gas, choose the appropriate cooling stage and use it to cool the graphene;

[0052] After the graphene is cooled to the set temperature, the generated graphene is collected and purified to completely remove the residual catalyst and other impurities. In this scheme, the graphene is purified by using a suitable purification technology in the prior art. The technicians in this field use a suitable purification technology and will not be described in detail in this scheme.

[0053] The filtering treatment device comprises a shell 1, and the two ends of the shell 1 are respectively connected to an input pipe and an output pipe. An air delivery pipe 2 is passed through the shell 1, and the air delivery pipe 2 comprises a flow guide pipe 21, and a flow diversion filter ring 22 is fixedly connected to the top of the flow guide pipe 21. A porous filter block 3 is sleeved on the air delivery pipe 2. The porous filter block 3 is made by a person skilled in the art using a material suitable for filtration and heat exchange in the prior art, such as a carbon fiber sponge;

[0054] The top of the shell 1 is detachably connected with a heat-insulating cover 4 matching the porous filter block 3, and a heat-exchange tube group 5 is passed through the heat-insulating cover 4. The heat-exchange tube group 5 includes a heat-exchange tube row 51 located in the heat-insulating cover 4. The heat-exchange tube row 51 is inserted into the porous filter block 3 and arranged around the diverter filter ring 22. The heat-exchange tube row 51 is spirally surrounded on the outside of the diverter filter ring 22; and the porous filter block 3 is covered and fixed on the heat-exchange tube row 51; when the heat-exchange tube row 51 is disassembled, the porous filter block 3 is removed simultaneously;

[0055] The input end and output end of the heat exchange tube bank 51 are connected to an air inlet pipe 52 and an air outlet pipe 53 respectively; the filtering treatment device is used to efficiently filter the tail gas discharged from the molten cracking furnace, remove particulate matter, and recover heat through the heat exchange tube group to improve energy utilization; and after the insulation cover 4 is removed, the porous filter block 3 can be replaced;

[0056] The particulate matter is effectively intercepted by the shunt filter ring 22 and the porous filter block 3, and the porous filter block 3 is used to exchange heat with the heat exchange tube row 51, and the particulate matter intercepted in the porous filter block 3 has passed through the porous filter block 3. The overall structure of the filtering treatment device is compact, the operation is convenient, and the heat recovery efficiency is significantly improved. Through the optimized design, the airflow inside the device is ensured to be evenly distributed, the heat exchange area is maximized, the energy utilization rate is further improved, and the production cost is reduced.

[0057] The top of the heat insulation cover 4 is fixedly connected with a voltage stabilizing assembly 6, which includes a pressure-adding device 61. A compression spring 62 is sleeved on the outer side of the movable end of the pressure-adding device 61. A sealing block 63 is inserted at the top of the diverter filter ring 22. A pressure sensor is installed at the top of the compression spring 62. A clamping ring matching the sealing block 63 is fixedly connected at the lower end of the compression spring 62. A sealing sleeve covering the compression spring 62 is connected between the top of the diverter filter ring 22 and the heat insulation cover 4. A brush layer is laid on the side wall of the sealing block 63 at one end of the inner side of the diverter filter ring 22. The pressure-adding device 61 monitors the airflow pressure in real time through the pressure sensor. When the detected pressure is greater than the set value, the pressure-adding device 61 is controlled to work so that its movable end pressurizes the sealing block 63 to maintain the stability of the sealing block 63. The position of the sealing block 63 is automatically adjusted according to the detected pressure to ensure the stability of the airflow output from the diverter filter ring 22.

[0058] By detecting the change in the detection value of the pressure sensor, the blockage condition of the shunt filter ring 22 and the porous filter block 3 is judged; this facilitates timely maintenance of the shunt filter ring 22 when it is blocked;

[0059] Furthermore, when the flow-dividing filter ring 22 is maintained, the sealing block 63 is driven to reciprocate at the flow-dividing filter ring 22 by the pressurizing device 61, so that the brush layer can effectively remove particles in the filter ring to prevent blockage.

[0060] An ash discharge mechanism 7 is connected between the bottom end of the flow guide pipe 21 and the input pipe. The ash discharge mechanism 7 includes a three-way pipe. The lower output end of the three-way pipe is fixedly connected to an ash discharge valve. The output end of the ash discharge valve is connected to an external suction pump. The side input end of the three-way pipe is connected to an on-off valve. The ash discharge mechanism 7 is used to discharge the particles intercepted by the diverter filter ring 22. When the ash discharge valve is opened, the on-off valve closes the input end of the gas transmission pipe 2. Then, the particles retained in the gas transmission pipe 2 are discharged through the action of the suction pump.

[0061] The tail gas separation equipment includes a first membrane separation device 8 and a hydrogen purification device 9. The first membrane separation device 8 is used to separate hydrogen-rich gas from the tail gas; the hydrogen purification device 9 is used to separate carbon dioxide and hydrogen from the hydrogen-rich gas;

[0062] The side gas output ends of the first membrane separation device 8 and the hydrogen purification device 9 are both equipped with temperature sensors; the hydrogen purification device 9 is connected to a carbon dioxide output pipe, on which a temperature sensor is installed; a cooling pipe is wound around the carbon dioxide output pipe; when the carbon dioxide separated by the hydrogen purification device 9 is output, its temperature is detected, and if its temperature is higher than the set value, the carbon dioxide is cooled by heat exchange by inputting a cooling airflow into the cooling pipe, so that when the carbon dioxide merges with the carbon dioxide-enriched gas to be dehydrated, its temperature will not easily rise to a high level, thereby affecting the condensation and dehydration effect. The cooling airflow in the cooling pipe is provided by an external cooling device to ensure a continuous and stable cooling effect;

[0063] This solution realizes the integration of efficient energy utilization and tail gas purification, reduces environmental pollution, improves the utilization rate of raw materials and energy, and optimizes the overall process flow.

[0064] Second implementation method:

[0065] Figure 6-7 A graphene preparation system based on natural gas containing carbon dioxide is shown, comprising a processor, to which a control module, a monitoring module, a data processing module and a data storage module are connected;

[0066] The control module is used to control the operation of the melt cracking furnace, the filtering treatment device and the tail gas separation equipment, and dynamically adjust the usage of the recovered gas and the utilization of the heat recovery fluid according to the instructions of the processor and the data provided by the monitoring module; for example, the control module can adjust the gas flow rate to ensure that the reaction conditions in the melt cracking furnace are maintained at the optimal state, and at the same time control the heat recovery of the tail gas. The recovered heat is used for the segmented cooling of the graphene to maximize the use of the generated heat and reduce energy waste.

[0067] The monitoring module collects monitoring data, including: recovered hydrogen flow, recovered carbon dioxide flow and temperature, and heat recovery fluid temperature;

[0068] The monitoring module is used to monitor and record key parameters in the preparation process in real time. In the scheme, the monitoring module mainly collects monitoring data including the amount of recovered gas and the state of heat recovery fluid. These data are crucial for optimizing the preparation process. For example, according to the proportion of carbon dioxide in natural gas, the concentration of natural gas and carbon dioxide is calculated and controlled, and at the same time, the appropriate catalyst is selected to control the output rate of graphene, ultimately achieving the maximum possible graphene output and full utilization of natural gas containing carbon dioxide.

[0069] The data processing module is used to analyze and process the monitoring data; and adjust the operating parameters of the molten cracking furnace and the working status of the filtration treatment device and the tail gas separation equipment according to the monitoring data to ensure efficient and stable operation of the system;

[0070] The data processing module analyzes and processes the data collected by the monitoring module; in the process of preparing graphene, the data processing module will analyze the data of the recovered gas volume and heat recovery fluid, and adjust and optimize the operating parameters of the melt cracking furnace, such as temperature, pressure and gas flow, based on these data. Through these optimizations, the output and quality of graphene can be improved, while ensuring the stability and safety of the entire preparation process.

[0071] The data storage module is used to record work logs, cracking working parameters and monitoring data;

[0072] The data stored in the data storage module include but are not limited to cracking parameters, gas flow, temperature changes, pressure changes, and final graphene production and quality; the data storage module ensures the traceability of all key information, facilitating subsequent analysis and quality control.

[0073] When the preparation system of this embodiment is working, the control module starts the melting cracking furnace according to the preset parameters, the monitoring module collects data in real time, and the data processing module adjusts the operating parameters after analysis to ensure the optimal reaction conditions; the filtering and processing device efficiently separates impurities, and at the same time, the inert gas is input into the filtering and processing device to recover the waste heat of the tail gas. The monitoring module monitors the temperature of the inert gas after heat exchange, and adjusts the inert gas flow rate according to the cooling stage of the graphene to ensure that the heat recovered by the inert gas is fully utilized;

[0074] When the tail gas separation equipment is working, hydrogen and carbon dioxide are recovered and stored. The data processing module adjusts the output of recovered hydrogen and carbon dioxide according to the amount of recovered hydrogen and carbon dioxide. When the amount of recovered hydrogen and carbon dioxide reaches the set value, the recovered hydrogen is mixed with natural gas in a set ratio and used for heating the molten cracking furnace; the recovered carbon dioxide is mixed with the stored enriched carbon dioxide for dehydration treatment.

[0075] The data storage module records the data of the entire process to ensure the efficient and stable operation of the system. This control system not only improves the efficiency of graphene preparation, but also greatly reduces energy consumption and waste emissions, achieving the goal of green and environmentally friendly production; at the same time, the system has a high degree of automation, reduces manual intervention, and improves the safety and reliability of production.

[0076] In summary, this solution achieves efficient utilization of natural gas resources containing carbon dioxide and maximizes the utilization of resources; through precise monitoring, data processing and regulation, it ensures the stability and controllability of the graphene preparation process and improves the quality and output of the product; the exhaust gas generated during the preparation process is effectively treated to reduce environmental pollution.

[0077] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A method for preparing graphene based on natural gas containing carbon dioxide, characterized in that: The specific steps include: A1: Preparation and pretreatment of raw materials; During the pretreatment stage, natural gas is filtered and dried to remove solid particle impurities and moisture; A2: Gas separation: First, the carbon dioxide and hydrocarbons in the natural gas are separated by a membrane separation device to obtain carbon dioxide-enriched gas and purified natural gas; The carbon dioxide-enriched gas is then dehydrated by a condensation dehydration device; and the sulfide impurities in the carbon dioxide-enriched gas are removed by a desulfurization device; Finally, the purified natural gas is mixed with the carbon dioxide-enriched gas according to demand, and the composition ratio of the gas is adjusted to meet the requirements for graphene preparation; A3: Preparation of graphene by cracking natural gas: In the preparation stage of the melt cracking furnace, the purified natural gas and the carbon dioxide-enriched gas mixture are introduced into the melt cracking furnace; The natural gas is cracked at a high temperature of 800 to 1000 degrees Celsius to decompose the natural gas into graphene. The tail gas generated by the reaction includes particulate matter, hydrogen, carbon dioxide and methane. The particulate matter includes carbon black and catalyst particles. A4: Tail gas treatment and recovery: The tail gas discharged from the molten cracking furnace is initially filtered through a filtering treatment device to remove particulate matter in the tail gas, and the heat of the tail gas is recovered through heat exchange between the inert gas and the tail gas during the filtering process; the inert gas after heat exchange is used to assist graphene cooling; After filtration, the tail gas is subjected to gas separation treatment by tail gas separation equipment to recover hydrogen and carbon dioxide in the tail gas; the recovered hydrogen is mixed with natural gas and used for heating the cracking furnace in A3; The recovered CO2 is mixed with the CO2-enriched gas before dehydration in A2 for further processing to reduce energy consumption; A5: Product collection and purification: The graphene in the molten cracking furnace is cooled in sections to the set temperature, and then the generated graphene is collected and purified to completely remove the residual catalyst and other impurities.

2. The method for preparing graphene based on natural gas containing carbon dioxide according to claim 1, characterized in that: The filtering treatment device comprises a shell (1), the two ends of the shell (1) are respectively connected to an input pipe and an output pipe, an air delivery pipe (2) is passed through the shell (1), the air delivery pipe (2) comprises a flow guide pipe (21), the top end of the flow guide pipe (21) is fixedly connected to a flow diversion filter ring (22), a porous filter block (3) is sleeved on the air delivery pipe (2), the top end of the shell (1) is detachably connected to a heat insulation cover (4) matching the porous filter block (3), a heat exchange tube group (5) is passed through the heat insulation cover (4), the heat exchange tube group (5) comprises a heat exchange tube row (51) located in the heat insulation cover (4), the heat exchange tube row (51) is inserted into the porous filter block (3) and is arranged around the flow diversion filter ring (22), and the input end and the output end of the heat exchange tube row (51) are respectively connected to an air inlet pipe (52) and an air outlet pipe (53).

3. The method for preparing graphene based on natural gas containing carbon dioxide according to claim 2, characterized in that: The top end of the heat insulation cover (4) is fixedly connected to a voltage stabilizing assembly (6), the voltage stabilizing assembly (6) comprises a pressure device (61), a compression spring (62) is sleeved on the outer side of the movable end of the pressure device (61), a sealing block (63) is inserted into the top end of the diverter filter ring (22), a pressure sensor is installed on the top end of the compression spring (62), a clamping ring matching the sealing block (63) is fixedly connected to the lower end of the compression spring (62), a sealing sleeve covering the compression spring (62) is connected between the top end of the diverter filter ring (22) and the heat insulation cover (4), and a brush layer is laid on the side wall of the sealing block (63) at one end inside the diverter filter ring (22).

4. The method for preparing graphene based on natural gas containing carbon dioxide according to claim 3, characterized in that: An ash unloading mechanism (7) is connected between the bottom end of the flow guide pipe (21) and the input pipe, and the ash unloading mechanism (7) comprises a three-way pipe, the lower output end of the three-way pipe is fixedly connected to an ash unloading valve; and the side input end of the three-way pipe is connected to an on-off valve.

5. The method for preparing graphene based on natural gas containing carbon dioxide according to claim 4, characterized in that: The tail gas separation equipment comprises a first membrane separation device (8) and a hydrogen purification device (9), wherein the first membrane separation device (8) is used to separate hydrogen-rich gas; and the hydrogen purification device (9) is used to separate carbon dioxide and hydrogen from the hydrogen-rich gas.

6. The method for preparing graphene based on natural gas containing carbon dioxide according to claim 5, characterized in that: The side gas output ends of the first membrane separation device (8) and the hydrogen purification device (9) are both equipped with temperature sensors; the hydrogen purification device (9) is connected to a carbon dioxide output pipe, on which a temperature sensor is installed; and a cooling pipe is wound around the carbon dioxide output pipe.

7. A system applied to the graphene preparation method according to claim 6, characterized in that: It includes a processor, to which a control module, a monitoring module, a data processing module and a data storage module are connected; The control module is used to control the operation of the melt cracking furnace, the filtering treatment device and the tail gas separation equipment, and dynamically adjust the usage of the recovered gas and the utilization of the heat recovery fluid according to the instructions of the processor and the data provided by the monitoring module; The monitoring module collects monitoring data, which includes: recovered hydrogen flow rate, recovered carbon dioxide flow rate and temperature, and heat recovery fluid temperature; The data processing module is used to analyze and process the monitoring data; and adjust the operating parameters of the molten cracking furnace and the working status of the filtering treatment device and the tail gas separation device according to the monitoring data; The data storage module is used to record work logs, cracking work parameters and monitoring data.

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