A system and method for plasma-assisted CO2 and methane atmospheric pressure reduction of methanol

Abstract

The present invention discloses a system and method for plasma-assisted CO2 and methane normal pressure methanol conversion. Methane and CO2 are respectively introduced into a warm plasma reactor to form a plasma jet reaction zone. Methane cracks to produce carbon black and hydrogen. After separation by a cyclone separator, the carbon black is introduced into CO2 plasma through a screw feeder to carry out a CO2+C→2CO reaction to produce high-purity CO. The high-purity CO is then reacted with the separated high-purity H2 downstream under the catalytic action of Ni-Ga to produce methanol under normal pressure. The present invention uses warm plasma to achieve methane decomposition and efficient activation of CO2 at normal pressure, obtains high-purity CO and H2 through multi-stage reaction regulation, and provides the heat required for further catalysis. Then, by means of the low energy barrier and small by-product characteristics of the CO hydrogenation reaction and the normal pressure catalytic activity of Ni-Ga, the normal pressure directional hydrogen-loss-free conversion of CO2 and methane to liquid fuel methanol is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of efficient utilization of greenhouse gases and methane and methanol synthesis, and in particular to a system and method for plasma-assisted CO2 and methane atmospheric pressure reduction into methanol. Background Art

[0002] In recent years, global warming caused by the greenhouse effect has wreaked havoc on Earth's ecology. As one of the most significant greenhouse gases, CO2 has become a focus of international attention. According to a recent report released by the International Energy Agency, global CO2 emissions from energy combustion and industrial processes increased by 6% year-on-year in 2021, reaching 36.3 billion tons. Methane, a plentiful clean energy gas, is also the second-most important greenhouse gas, contributing 15%. Consequently, the production of high-value products from the reforming of CO2 and methane has attracted considerable attention from scholars both domestically and internationally.

[0003] Nobel Prize winner in Chemistry George A. Olah proposed the concept of a "methanol economy," which involves using liquid methanol as an energy storage material instead of the currently widely used fossil fuels, while also recycling CO2 from industrial waste gas or the atmosphere to produce methanol. Currently, over 80% of methanol is produced using natural gas as a feedstock, via the Fischer-Tropsch synthesis of the intermediate product synthesis gas (CO + 2H2 → CH3OH). The methane-carbon dioxide dry reforming (DMR) process uses methane and carbon dioxide, two widely available greenhouse gases, as feedstocks to produce synthesis gas (CH4 + CO2 → 2CO + 2H2). This is a clean conversion route that achieves resourceful utilization of greenhouse gases and reduces carbon emissions at the source, thus having significant environmental implications.

[0004] However, the direct production of methanol from CO2 and methane is extremely difficult, requiring energy input to excite inactive molecules and regulate complex reaction processes. It is also limited by catalyst carbon deposition and deactivation and high costs. Currently, there is still a lack of feasible and efficient technical routes. Therefore, domestic scholars have conducted in-depth research in this direction.

[0005] Ran Dong et al. designed a process combining steam reforming (SMR) and carbon dioxide reforming (DMR) in series and parallel to produce synthesis gas with a suitable hydrogen-carbon ratio. Sun Ling et al. proposed a methane-to-methanol process based on chain-cycle carbon dioxide reforming. However, the methane dry reforming reaction of the above-mentioned traditional thermal catalytic system needs to be carried out at high temperature (>700℃), and the high temperature process often causes carbon deposition and sintering of active species.

[0006] Professor Xu Dongsheng's team at Peking University has invented a highly active and carbon-deposition-resistant methane dry reforming photocatalyst, Rh / CexWO3, which has both photo-thermal and photo-electric effects. They have also demonstrated its excellent activity in the methane dry reforming reaction, providing guidance for the design of photocatalytic systems. However, due to the generally low photocatalytic yield, its application will be subject to certain limitations. Summary of the Invention

[0007] The present invention addresses the shortcomings of existing technologies by proposing a technology that uses CO2 and CH4 as raw materials, exploits the high reactivity of plasma at atmospheric pressure, produces synthesis gas through a stepwise reaction, and utilizes the atmospheric catalytic activity of Ni-Ga catalysts in methanol synthesis to produce methanol. This technology addresses the high investment cost, bulky equipment, high temperature and high pressure requirements, and catalyst deactivation issues inherent in traditional thermal catalytic methanol production systems. It also avoids the generally low yields associated with photoelectrocatalytic systems, and therefore has broad application prospects.

[0008] Provided are a system and method for plasma-assisted atmospheric compression of methanol using CO2 and methane.

[0009] The object of the present invention is achieved through the following technical solutions:

[0010] According to a first aspect of the present specification, there is provided a plasma-assisted CO2 and methane atmospheric pressure methanol production system, the system comprising: a methane cracking module, a reverse Boudouard reaction module and a Fischer-Tropsch reaction synthesis module;

[0011] The methane reaction module includes: a first high-voltage power supply, a CH4 plasma reactor, a first cyclone separator, a carbon storage bin, a feeding valve, a screw feeder and a first online infrared analyzer;

[0012] The first high-voltage power supply is connected to the CH4 plasma reactor, and the solid phase output port of the first cyclone separator is connected to the carbon storage bin through a pipeline for storing the carbon black obtained by the above reaction, and a feeding valve is provided on the pipeline; the gas phase output port is connected to the exhaust pipe, and a sampling pipe is led out from the exhaust pipe to collect gas into the first online infrared analyzer; the spiral feeder is tilted downward, with the front end connected to the carbon storage bin feeding pipe and the rear end connected to the CO2 plasma reactor feeding port;

[0013] The reverse Boudouard reaction module includes: a second high-voltage power supply, a CO2 plasma reactor, a second cyclone separator, a return valve and a second online infrared analyzer;

[0014] A second high-voltage power supply is connected to the CO2 plasma reactor. The solid phase output port of the second cyclone separator is connected to the return port of the quartz cover in the CO2 plasma reactor through a pipeline, so that the incompletely reacted carbon black can re-participate in the reaction. A return valve is provided on the pipeline. The gas phase output port is connected to the exhaust pipe, and a sampling pipe is led out from the exhaust pipe to collect gas and enter the second online infrared analyzer.

[0015] The Fischer-Tropsch reaction synthesis module includes: a check valve, a first buffer container, a second buffer container, a flow meter, a centrifugal pump, a pressure gauge, a catalytic bed, a third online infrared analyzer, a vacuum drying oven, a cold trap, and a vacuum pump;

[0016] The front end of the first buffer container is connected to the exhaust pipe of the first cyclone separator, the front end of the second buffer container is connected to the exhaust pipe of the second cyclone separator, and the rear end is connected to the catalytic bed; a check valve is installed at the front and rear of the first buffer container and the second buffer container to prevent the backflow of high-temperature gas, and a centrifugal pump is also installed in the pipeline behind the first buffer container and the second buffer container to transport CO and control the CO supply amount;

[0017] The bottom of the catalyst bed is connected to the pipes of the first and second buffer containers. The gaseous reaction products enter the vacuum drying oven and the cold trap in sequence through the outlet pipe above the catalyst bed to further purify and collect the products. A sampling tube is led out from the outlet pipe to collect a small amount of product gas and enter the third online infrared analyzer to guide the operating power of the centrifugal pump. The excess waste gas is discharged through the vacuum pump connected to the vacuum drying oven and the cold trap.

[0018] Furthermore, the CH4 plasma reactor is inverted and located above the other components of the entire reaction system, and the position of the CH4 gas inlet corresponds to the lower 1 / 4 to 1 / 5 of the height of the electrode in the CH4 plasma reactor, and the position of the CO2 gas inlet corresponds to the upper 1 / 4 to 1 / 5 of the height of the electrode in the CO2 plasma reactor.

[0019] Furthermore, the first online infrared analyzer is connected to the first high-voltage power supply through a circuit, the second online infrared analyzer is connected to the second high-voltage power supply and the screw feeder through a circuit; the third online infrared analyzer is connected to the centrifugal pump through a circuit;

[0020] The results of the first online infrared analyzer are used as feedback to guide the voltage of the first high-voltage power supply. When the CH4 concentration in the incoming gas flow is high, the voltage of the high-voltage power supply is increased to obtain purer H2;

[0021] The result of the second online infrared analyzer is used to feedback and adjust the voltage of the second high-voltage power supply and the feeding rate of the screw feeder;

[0022] The result of the third online infrared analyzer is used to feedback and adjust the operating parameters of the first and second centrifugal pumps, thereby controlling CO and H2 to participate in the reaction at an optimal supply ratio of 1:2.

[0023] Furthermore, pressure gauges and flow meters are installed on the pipelines connecting the first buffer container and the second buffer container to the catalytic bed; the pressure gauges are used to measure the pressure of CO and H2 on the two pipelines, and the flow meters are used to monitor the flow of CO and H2 on the two pipelines.

[0024] Furthermore, the CH4 plasma reactor, CO2 plasma reactor and catalytic bed are all equipped with thermocouples for temperature monitoring.

[0025] Furthermore, the first buffer container and the second buffer container are both made of thermal insulation materials to ensure the reaction temperature of the subsequent methanol synthesis.

[0026] Furthermore, the catalyst bed adopts Ni-Ga catalyst to achieve catalytic synthesis of methanol at normal pressure, and a pressure gauge is provided to measure the reaction temperature and pressure.

[0027] Furthermore, the Ni-Ga catalyst is prepared by dropping a mixed aqueous solution of nickel and gallium nitrate onto silicon dioxide through an incipient wetness impregnation method.

[0028] Furthermore, the cold trap uses water as the cooling medium, and the cooling water temperature should be less than 50°C.

[0029] According to a second aspect of the present specification, a plasma-assisted method for extracting methanol from greenhouse gases and methane under normal pressure is provided, the method comprising the following steps:

[0030] First, methane is introduced into an inverted CH4 plasma reactor to form a plasma jet reaction zone. Under the heat provided by the warm plasma, methane is cracked to produce carbon black and hydrogen (CH4→C+2H2). The carbon black falls into a cyclone separator under the action of gravity and jet inertia for further gas-solid separation.

[0031] The separated carbon black is stored in a carbon storage bin. When needed, the feed valve is opened and the carbon black is fed into the CO2 plasma reactor through an inclined screw feeder under the action of gravity. It undergoes a reverse Boudouard reaction with the CO2 plasma jet discharged from a high-voltage power supply. The reaction formula is CO2+C→2CO, producing high-purity CO. The CO and the H2 separated by the above-mentioned cyclone separator enter two buffer pressure vessels respectively. After the pressure is stabilized, they are transported by centrifugal pumps to the catalyst bed. The buffer vessel shell is made of insulating material, which can reduce heat loss of the reaction products and provide the high temperature required for the subsequent hydrogenation reaction.

[0032] The catalyst bed uses Ni-Ga catalyst. Based on the normal pressure catalytic activity of Ni-Ga catalyst and the good heat and mass transfer characteristics of the catalyst in the fluidized state, efficient normal pressure directional production of methanol can be achieved; the reaction formula is CO+2H2→CH3OH. The methanol is condensed in the cold trap and collected, and the remaining waste gas leaves the reaction system under the suction action of the vacuum pump.

[0033] Beneficial effects of the present invention:

[0034] (1) The present invention designs a relatively complete reaction system that can achieve multi-stage directional and integrated production of methanol. In reaction one (CH4→C+2H2), the methane cracking products C and H2 are separated by a cyclone separator. The former is used as a reactant in reaction two, and the latter is used as a reactant in reaction three. Reaction two (CO2+C→2CO) is a reverse Boudouard reaction. C from reaction one and greenhouse gas CO2 are used as reaction raw materials. The high-purity CO produced and the product H2 of reaction one are jointly used in reaction three (CO+2H2→CH3OH) to produce methanol, thus avoiding the loss of hydrogen source caused by the direct reaction of CO2 and H2 to produce a large amount of H2O.

[0035] (2) The present invention adopts warm plasma technology to achieve normal pressure decomposition of CH4 and normal pressure efficient activation of CO2. The technical process is simple, the operating cost is low, the response speed is fast, and it is suitable for decentralized small-scale production scenarios.

[0036] (3) Ni-Ga catalyst is used to participate in the final hydrogenation reaction. There is no report on its application in CO hydrogenation reaction. However, many studies have shown that CO is an important intermediate in CO2 hydrogenation reaction, and its hydrogenation reaction has a low energy barrier. Therefore, Ni-Ga catalyst can play a catalytic role in the CO atmospheric pressure hydrogenation reaction. Achieving atmospheric pressure can expand the application scenarios and reduce operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the system structure for plasma-assisted CO2 and methane atmospheric pressure reduction of methanol. DETAILED DESCRIPTION

[0038] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0039] like Figure 1 As shown, the present invention provides a plasma-assisted system and method for producing methanol by atmospheric pressure using CO2 and methane, comprising a methane reaction module, a reverse Boudouard reaction module, and a Fischer-Tropsch reaction synthesis module;

[0040] The methane reaction module includes a first high-voltage power supply 1, a CH4 plasma reactor 2, a first thermocouple 3, a second thermocouple 4, a first cyclone separator 5, a carbon storage bin 6, a feed valve 7, a screw feeder 8 and a first online infrared analyzer 15.

[0041] The reverse Boudouard reaction module includes a second high voltage power supply 9, a CO2 plasma reactor 10, a third thermocouple 11, a fourth thermocouple 12, a second cyclone separator 13, a return valve 14, a second online infrared analyzer 16,

[0042] The Fischer-Tropsch reaction synthesis module includes a first check valve 17, a second check valve 18, a first buffer container 19, a second buffer container 20, a third check valve 21, a fourth check valve 22, a first flow meter 23, a second flow meter 24, a first centrifugal pump 25, a second centrifugal pump 26, a first pressure gauge 27, a second pressure gauge 28, a fifth thermocouple 29, a sixth thermocouple 30, a catalytic bed 31, a third pressure gauge 32, a third online infrared analyzer 33, a vacuum drying oven 34, a cold trap 35, and a vacuum pump 36. The arrows in the figure indicate the flow direction of the reactants.

[0043] The CH4 plasma reactor 2 is positioned in an inverted position, located above the CO2 plasma reactor 10 and other components of the entire reaction system. The CH4 plasma reactor 2 is connected to a first high-voltage power supply 1 via electrode leads. CH4 enters tangentially from the outer electrode wall inlet of the CH4 plasma reactor 2. When the first high-voltage power supply 1 is turned on, the CH4 between the inner and outer electrodes breaks down under the action of the high voltage, generating a discharge arc. Driven by the airflow, the discharge arc forms a plasma jet that flows into the quartz shroud. Within the quartz shroud, the high-temperature cracking produces carbon black and hydrogen (CH4 → C + 2H2). This reaction is endothermic, and the high temperature required is provided by the energy carried by the warm plasma generated by the high-voltage discharge. Furthermore, no carbon oxides are produced during the reaction, and the hydrogen is of high purity, providing a large amount of carbon deposits. The carbon deposits fall into the first cyclone separator 5 under the influence of gravity and the jet, thus avoiding the problem of reaction inhibition caused by localized accumulation. The reactor is equipped with a first thermocouple 3 and a second thermocouple 4, located at the inlet and outlet sections of the quartz shroud, respectively. The first thermocouple 3 is used to monitor the temperature of the CH4 plasma jet, and the second thermocouple 4 is used to monitor the cracking reaction temperature.

[0044] The reaction products flow out through a pipeline connected to the bottom of the quartz hood of the CH4 plasma reactor 2 and enter the first cyclone separator 5, where gravity and centrifugal force achieve gas-solid separation of carbon black and hydrogen. The separated solid carbon black is temporarily stored in the carbon storage bin 6. When needed, the feed valve 7 is opened and the stored carbon black is fed into the CO2 plasma reactor 10 via a screw feeder 8 to serve as the raw material for the subsequent reverse Boudouard reaction (CO2 + C → 2CO). The screw feeder 8 is electrically connected to a second online infrared analyzer 16, and the feed rate is controlled based on feedback from the second online infrared analyzer 16.

[0045] The separated H2 gaseous phase is passed into the first buffer container 19 to stabilize the pressure. Driven by the first centrifugal pump 25, it enters the catalytic bed 31 and serves as the feedstock for Reaction 3 (CO + 2H2 → CH3OH). The first online infrared analyzer 15 samples the gas flow and analyzes its components (CH4, H2, O2, and C2H2). This feedback guides the voltage of the first pulsating DC high-voltage power supply 1. When the CH4 concentration in the incoming gas flow is high, the voltage of the first pulsating DC high-voltage power supply 1 is increased to obtain a purer H2 feedstock.

[0046] The CO2 gas flow enters tangentially from the lower inlet of the outer electrode wall of the CO2 plasma reactor 10. After entering the CO2 plasma reactor 10, the CO2 is transformed into a plasma through the discharge arc generated between the inner and outer electrodes of the second high-voltage power supply 9. Driven by the gas flow, the CO2 forms a plasma jet. After passing through the air distribution plate inside the quartz shroud, the plasma jet forms multiple micro-jet CO2 plasmas. These flow into the reaction zone of the quartz shroud and react with the carbon from the screw feeder 8 in the quartz shroud within the CO2 plasma reactor 10 to undergo a reverse Boudouard reaction (CO2 + C → 2CO). A third thermocouple 11 and a fourth thermocouple 12 are provided to measure the temperature of the jet zone and the gas-solid fluidization reaction zone, respectively. The temperature of the micro-jet at the third thermocouple 11 is generally between 500-650°C, while the temperature at the fourth thermocouple 12 should be around 500°C to ensure a good treatment effect. The reaction products flow out through a pipe connected to the upper end of the quartz shield of the CO2 plasma reactor 10. A small amount of unreacted carbon black mixed in the gas flow is separated by the second cyclone separator 13 and returned to the plasma reactor through the return valve 14 to participate in the reaction. The separated high-purity CO is passed into the second buffer container 20 to stabilize the pressure. Driven by the second centrifugal pump 26, it enters the catalytic bed 31 and serves as the feedstock for Reaction 3 (CO + 2H2 → CH3OH).

[0047] The airflow separated by the second cyclone separator 13 is sampled and analyzed for its components (CO, O₂, and CO₂) by a second online infrared analyzer 16. The results of the online infrared analyzer 16 are used to feedback and adjust the pulsating DC voltage of the second high-voltage power supply 9 and the feed rate of the screw feeder 8. When the CO₂ concentration in the product is high, the voltage of the pulsating DC second high-voltage power supply 9 and the feed rate of the screw feeder 8 can be increased to achieve the optimal CO₂ conversion rate.

[0048] The first and second buffer containers 19 and 20 provide a certain margin for the catalyst bed and stabilize the pressures of CO and H₂. The buffer shells are constructed of insulating material to reduce heat loss and utilize waste heat to elevate the initial temperature of reaction three. The pipelines leading from the two buffer containers are equipped with a first check valve 17, a second check valve 18, a third check valve 21, and a fourth check valve 22 to prevent backflow of high-temperature gases. The pipelines from the two buffer containers to the catalytic bed 31 are equipped with a first flowmeter 23, a second flowmeter 24, a first centrifugal pump 25, a second centrifugal pump 26, a first pressure gauge 27, and a second pressure gauge 28. The flowmeters monitor the flow of reactants, while the centrifugal pumps transport the reactants and control the ratio of CO and H₂ to 1:2 for the methanol synthesis reaction. The pressure gauges measure the pressures of CO and H₂ in the two pipelines.

[0049] After CO and H2 enter the catalytic bed 31, the Ni-Ga catalyst converts them to methanol at atmospheric pressure without hydrogen loss (CO + 2H2 → CH3OH). Due to the turbulent fluidization, CO and H2 can fully contact the catalyst, and the methanol gas produced by the reaction is promptly discharged, avoiding the problem of reduced reaction efficiency caused by product accumulation. The Ni-Ga catalyst is prepared by dropwise depositing a mixed aqueous solution of nickel and gallium nitrate onto silica using the incipient wetness impregnation method. Its excellent performance is due to the Ga species-rich surface and the effective manipulation of the Ni electronic structure, which optimizes the selectivity of the surface metal active sites for the methanol synthesis reaction. Compared to the conventional commercial Cu / ZnO / Al2O3 catalyst, the Ni-Ga catalyst exhibits higher intrinsic activity for methanol synthesis, with selectivity reaching 90-100% at atmospheric pressure. It can reduce energy consumption in the production process by over 57%, making it suitable for decentralized and miniaturized applications.

[0050] The fifth thermocouple 29, the sixth thermocouple 30 and the third pressure gauge 32 monitor the temperature and pressure of the catalyst bed respectively. The thermodynamic parameters of the reaction process require a temperature of 200-300°C and a pressure of 5-10 MPa.

[0051] A third online infrared analyzer 33 samples the product gas from the catalytic bed and analyzes its composition (CH3OH, CO, H2, CH4, CO2). The results are used to adjust the operating parameters of the first and second centrifugal pumps 25 and 26, thereby controlling the CO and H2 supply ratio to an optimal 1:2 ratio for reaction three. A vacuum drying oven 34 and a cold trap 35 further purify the product. The cold trap uses water as the cooling medium, and the cooling water temperature should be below 50°C to ensure optimal condensation. Excess exhaust gas is drawn out of the system by the vacuum pump, and the purified CH3OH is collected as a liquid at the bottom of the cold trap.

[0052] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A plasma-assisted system for the atmospheric compression of CO2 and methane into methanol, characterized in that: The system includes: a methane reaction module, a reverse Boudouard reaction module and a Fischer-Tropsch reaction synthesis module; The methane reaction module includes: a first high-voltage power supply, a CH4 plasma reactor, a first cyclone separator, a carbon storage bin, a feeding valve, a screw feeder and a first online infrared analyzer; The first high-voltage power supply is connected to the CH4 plasma reactor, and the solid phase output port of the first cyclone separator is connected to the carbon storage bin through a pipeline for storing the carbon black obtained by the methane reaction, and a feeding valve is provided on the pipeline; the gas phase output port is connected to the exhaust pipe, and a sampling pipe is led out from the exhaust pipe to collect gas into the first online infrared analyzer; the spiral feeder is tilted downward, with the front end connected to the carbon storage bin feeding pipe and the rear end connected to the CO2 plasma reactor feeding port; The reverse Boudouard reaction module includes: a second high-voltage power supply, a CO2 plasma reactor, a second cyclone separator, a return valve and a second online infrared analyzer; A second high-voltage power supply is connected to the CO2 plasma reactor. The solid phase output port of the second cyclone separator is connected to the return port of the quartz cover in the CO2 plasma reactor through a pipeline, so that the incompletely reacted carbon black can re-participate in the reaction. A return valve is provided on the pipeline. The gas phase output port is connected to the exhaust pipe, and a sampling pipe is led out from the exhaust pipe to collect gas and enter the second online infrared analyzer. The Fischer-Tropsch reaction synthesis module includes: a check valve, a first buffer container, a second buffer container, a flow meter, a centrifugal pump, a pressure gauge, a catalytic bed, a third online infrared analyzer, a vacuum drying oven, a cold trap, and a vacuum pump; The front end of the first buffer container is connected to the exhaust pipe of the first cyclone separator, the front end of the second buffer container is connected to the exhaust pipe of the second cyclone separator, and the rear end is connected to the catalytic bed; a check valve is installed at the front and rear of the first buffer container and the second buffer container to prevent the backflow of high-temperature gas, and a centrifugal pump is also installed in the pipeline behind the first buffer container and the second buffer container to transport CO and control the CO supply amount; The bottom of the catalytic bed is connected to the pipes of the first and second buffer containers. The gaseous reaction products enter the vacuum drying oven and the cold trap in sequence through the outlet pipe above the catalyst bed for further purification and collection of the products. A sampling tube is led out from the outlet pipe to collect a small amount of product gas and enter the third online infrared analyzer to guide the operating power of the centrifugal pump. Excess waste gas is discharged through a vacuum pump connected to the vacuum drying oven and the cold trap. The catalytic bed uses a Ni-Ga catalyst to achieve catalytic synthesis of methanol at normal pressure, and a pressure gauge is provided to measure the reaction temperature and pressure. The first online infrared analyzer is connected to a first high-voltage power supply via a circuit, the second online infrared analyzer is connected to a second high-voltage power supply and a screw feeder via a circuit; the third online infrared analyzer is connected to a centrifugal pump via a circuit; The results of the first online infrared analyzer are used as feedback to guide the voltage of the first high-voltage power supply. When the CH4 concentration in the incoming gas flow is high, the voltage of the high-voltage power supply is increased to obtain purer H2; The result of the second online infrared analyzer is used to feedback and adjust the voltage of the second high-voltage power supply and the feeding rate of the screw feeder; The results of the third online infrared analyzer are used to feedback and adjust the operating parameters of the first and second centrifugal pumps, thereby controlling CO and H2 to participate in the reaction at an optimal supply ratio of 1:2; It is characterized in that pressure gauges and flow meters are installed on the pipelines connecting the first buffer container and the second buffer container to the catalytic bed; the pressure gauges are used to measure the pressure of CO and H2 on the two pipelines, and the flow meters are used to monitor the flow of CO and H2 on the two pipelines.

2. The plasma-assisted CO2 and methane atmospheric pressure methanol conversion system according to claim 1, characterized in that: The CH4 plasma reactor is inverted and located above the other components of the entire reaction system. The position of the CH4 gas inlet corresponds to the lower 1 / 4 to 1 / 5 of the height of the electrode in the CH4 plasma reactor, and the position of the CO2 gas inlet corresponds to the upper 1 / 4 to 1 / 5 of the height of the electrode in the CO2 plasma reactor.

3. The plasma-assisted CO2 and methane atmospheric pressure methanol conversion system according to claim 1, characterized in that: The CH4 plasma reactor, CO2 plasma reactor and catalytic bed are all equipped with thermocouples for temperature monitoring.

4. The plasma-assisted CO2 and methane atmospheric pressure methanol conversion system according to claim 1, characterized in that: The first buffer container and the second buffer container are both made of thermal insulation materials to ensure the reaction temperature of subsequent methanol synthesis.

5. The plasma-assisted CO2 and methane atmospheric pressure methanol conversion system according to claim 1, characterized in that: The Ni-Ga catalyst is prepared by dropping a mixed aqueous solution of nickel and gallium nitrate onto silicon dioxide through an incipient wetness impregnation method.

6. The plasma-assisted CO2 and methane atmospheric pressure methanol conversion system according to claim 1, characterized in that: The cold trap uses water as the cooling medium, and the cooling water temperature should be less than 50℃.

7. A method for producing methanol by atmospheric pressure using plasma-assisted CO2 and methane using the system according to any one of claims 1 to 6, characterized in that: The following steps are involved: First, methane is introduced into an inverted CH4 plasma reactor to form a plasma jet reaction zone. Under the heat provided by the warm plasma, methane is cracked to produce carbon black and hydrogen with the reaction formula of CH4→C+2H2. The carbon black falls into the cyclone separator under the action of gravity and jet inertia for further gas-solid separation. The separated carbon black is stored in a carbon storage bin. When needed, the feed valve is opened and the carbon black is fed into the CO2 plasma reactor through an inclined screw feeder under the action of gravity. It undergoes a reverse Boudouard reaction with the CO2 plasma jet discharged from a high-voltage power supply. The reaction formula is CO2+C→2CO, producing high-purity CO. The CO and the H2 separated by the cyclone separator enter two buffer pressure vessels respectively. After the pressure is stabilized, they are transported by centrifugal pumps to the catalyst bed. The buffer vessel shell is made of insulating material, which can reduce heat loss of the reaction products and provide the high temperature required for the subsequent hydrogenation reaction. The catalyst bed uses Ni-Ga catalyst. Based on the normal pressure catalytic activity of Ni-Ga catalyst and the good heat and mass transfer characteristics of the catalyst in the fluidized state, efficient normal pressure directional production of methanol is achieved; the reaction formula is CO+2H2→CH3OH. The methanol is condensed in a cold trap and collected, and the remaining waste gas leaves the reaction system under the suction of a vacuum pump.

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