Green electricity utilization system and method for synthesizing methanol by hydrogenation of co 2 under catalysis using plasma

Abstract

A green electricity utilization system and method for synthesizing methanol by hydrogenation of CO2 under catalysis using plasma. H2 obtained by electrolyzing water and CO2 captured in an industrial process are firstly subjected to a reversed water-gas shift reaction under the efficient driving of atmospheric-pressure jet plasma, so that a mixed product of CO / CO2 / H2 is obtained, the mixed product passes through a buffer storage tank and then is subjected to multi-stage pressurization, and green methanol is further efficiently synthesized in a thermal catalytic bed. A two-stage methanol synthesis system involving plasma CO2 pre-conversion and CO / CO2 catalytic hydrogenation is used, such that the problems of catalyst inactivation and too high reaction temperature in traditional thermal catalytic reversed water-gas shift reaction are solved, and the thermokinetic bottleneck of a CO2 direct catalytic hydrogenation reaction is overcome. A plasma reaction device has high energy efficiency, involves rapid starting and stopping, and can be directly driven by fluctuating power; and the system keeps the operation stability of a catalytic system by means of intermediate product storage and multi-stage pressurization.

Description

Green electricity consumption system and method for plasma-catalyzed CO2 hydrogenation to methanol Technical Field

[0001] The present invention belongs to the field of greenhouse gas resource utilization and new energy power consumption, and relates to a green electricity consumption system and method for synthesizing methanol by plasma-catalyzed CO2 hydrogenation. Background Art

[0002] The catalytic hydrogenation of CO2 to methanol is a hot topic of international research. CO2 is a major greenhouse gas with a wide range of sources, while hydrogen is easily obtained through electrolysis of water using renewable energy. Methanol, a high-value-added product, is a liquid, allowing for direct utilization of existing transportation and power equipment. Its high energy density and clean, efficient combustion make it an ideal green fuel or green hydrogen carrier. Methanol is also the fourth largest basic chemical raw material, enabling the production of hundreds of chemical products. Furthermore, with renewable energy power becoming the primary energy source and investment and operating costs significantly decreasing, research on the catalytic hydrogenation of CO2 to methanol using green electricity has garnered significant attention.

[0003] Research and development of CO2 hydrogenation to methanol under thermal catalytic conditions began early. In 1993, Lurgi launched the world's first CO2 hydrogenation to methanol demonstration project. Domestic institutions such as the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and the Shanghai Advanced Research Institute have conducted extensive research and development in this area. For example, the skid-type unit developed by the Dalian Institute of Chemical Physics and CNPC achieves a CO2 conversion rate of 20% and a methanol selectivity of 70%.

[0004] However, the technology of synthesizing methanol by thermal catalytic CO2 hydrogenation has the following difficulties: due to the limitations of thermodynamics and kinetics, its single-pass conversion rate is still at a relatively low level (generally <20%), and it needs to work under relatively high pressure conditions (generally >5Mpa); in addition, the catalytic process has a complex technological flow, poor flexibility, and a long response time (generally at the hourly level), making it difficult to adapt to the significant volatility of renewable energy electricity, thus limiting its large-scale promotion and application.

[0005] Therefore, a method and system are needed that can simultaneously solve the above-mentioned difficulties, realize low-energy, flexible and orderly conversion of CO2 to methanol, and adapt to the high volatility of new energy electricity. It will greatly improve the application prospects of green electricity-driven CO2 hydrogenation reactions, and at the same time realize the efficient chemical energy storage and consumption of green electricity and the synergistic conversion and utilization of greenhouse gas CO2, and expand a transformative idea for achieving carbon peak and carbon neutrality.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to address the deficiencies of the existing technology and provide a green electricity consumption system and method for synthesizing methanol by plasma-catalyzed CO2 hydrogenation.

[0008] The object of the present invention is achieved through the following technical solutions:

[0009] According to the first aspect of this specification, a green electricity consumption system for synthesizing methanol by plasma-catalyzed CO2 hydrogenation is provided, comprising a jet plasma reaction tower, a methanol synthesis reactor, a supply system, a storage and pressurization system, a power supply, and a purification and treatment system;

[0010] The supply system is used to provide H2 and CO2 to the plasma reactor;

[0011] The jet plasma reaction tower is used to pre-activate and convert CO2 using jet plasma, so that the CO2 and H2 undergo a reverse water-gas shift reaction to produce a CO / CO2 / H2 mixed intermediate product at normal pressure and low temperature;

[0012] The storage and pressurization system includes a mixed gas intermediate storage tank and a multi-stage pressurization system; it is used to store the CO / CO2 / H2 mixed gas generated by the jet plasma reactor and pressurize it, thereby achieving decoupling of the jet plasma reactor and the methanol reactor;

[0013] The methanol synthesis reactor is used to synthesize methanol from the mixed gas delivered by the storage and pressurization system under the action of a catalyst;

[0014] The power supply is used to supply power to the plasma reactor, the formaldehyde synthesis reactor and the supply system;

[0015] The purification system is used to separate methanol from residual reaction gas and purify the methanol.

[0016] Furthermore, the supply system includes a water electrolysis hydrogen production reactor, an H2 storage tank, a CO2 storage tank, a water pump, a first flow controller and a heat exchanger; wherein the water pump, the first flow controller and the heat exchanger are used to transport H2O to the water electrolysis hydrogen production reactor and control the flow, and the water electrolysis hydrogen production reactor is connected to the H2 storage tank.

[0017] Furthermore, the output ends of the H2 storage tank, CO2 storage tank and mixed intermediate product storage tank are all provided with a check valve, a flow controller and a centrifugal pump.

[0018] Furthermore, the top of the jet plasma reaction tower is a gas collection area that sends the gas to the mixed gas intermediate storage tank, and the bottom is a liquid collection pipeline. Three jet plasma reaction groups are evenly arranged at different heights on the same side of the tower body. Each jet plasma reaction group contains six jet plasma reactors, which are symmetrically distributed in a hexagonal array and fixed on a disc-shaped base 18; three sight glasses are distributed on the other side of the tower body for observing the reaction process, and temperature and pressure sensors are installed on the wall of the reaction tower.

[0019] Furthermore, the isoplasma reactor comprises an outer electrode, an inner electrode, a CO2 / H2 air inlet and a base;

[0020] The outer electrode is fixed on the insulating base and is a hollow sleeve-type electrode with a tapered outlet structure at the top;

[0021] The inner electrode is a conical electrode, placed in the lower middle position of the hollow structure of the outer electrode, and is formed integrally by a lower cylinder and an upper frustum. The bottom of the inner electrode is fixed to the base and is connected to the high-voltage end of the plasma power supply via an electrode lead passing through the base. The outer wall of the inner electrode is parallel to the inner wall of the outer electrode. The wall surface of the outer electrode is provided with an H2 / CO2 air inlet, which is located at the bottom of the reaction device and enters tangentially from the bottom of the reactor, forming a rotating upward airflow in the gap between the inner and outer electrodes, driving the arc between the electrodes to rotate and rise, and under the action of the tapered outlet, the plasma is ejected in the form of a jet. The outer and inner electrodes are connected to a frequency-adjustable high-voltage AC power supply.

[0022] Furthermore, the methanol synthesis reactor is provided with a CO / CO2 hydrogenation to methanol reaction zone and a crude methanol outlet. CO / CO2 and H2 are directionally synthesized into crude methanol at normal pressure under the catalysis of a copper-based composite nanocatalyst. The crude methanol is passed through the crude methanol outlet into a purification treatment system for purification, thereby realizing efficient chemical energy storage of abandoned electricity / valley electricity and synergistic conversion and utilization of greenhouse gas CO2.

[0023] Furthermore, the multi-stage boosting system includes a boosting pump, a buffer tank, a back pressure valve and a real-time pressure monitoring system.

[0024] Furthermore, the purification treatment system is specifically composed of: a reheater, a gas-liquid desuperheater, a flash tank, a methanol distillation tower and a methanol storage tank connected in sequence, wherein the liquid channel of the flash tank is directly connected to the methanol distillation tower, and the gas channel is connected to the methanol synthesis reactor and the methanol distillation tower; it is used to separate methanol and residual reaction gas and purify the methanol.

[0025] Furthermore, the power supply includes a water electrolysis hydrogen production power supply, a jet plasma reactor power supply and a multi-stage boosting system power supply, which are respectively used to power the water electrolysis hydrogen production reactor, the jet plasma reactor and the multi-stage boosting system, all of which are based on off-grid renewable energy power generation.

[0026] According to another aspect of the present invention, a method for consuming green electricity by plasma-catalyzed CO2 hydrogenation to synthesize methanol is provided, the method comprising:

[0027] Step 1: Turn on the power supply to perform the step of electrolyzing water to produce hydrogen, and the produced hydrogen is directly passed into the H2 storage tank for storage;

[0028] Step 2: Open the CO2 storage tank and the H2 storage tank, mix the gases in a certain proportion and introduce them into the jet plasma reactor. Turn on the power to form a rotating airflow inside the mixed gas, drive the arc between the electrodes to rotate and rise, and eject the plasma in the form of a jet under the action of the gradually converging outlet. The power and intake flow of each reactor are flexibly controlled, and the temperature value is monitored in real time. The CO2 pre-activation conversion is completed, and the reaction is as follows:

[0029] CO2+H2=CO+H2O

[0030] Step 3: After the reaction is completed, the mixed gas generated rises after passing through the air distribution plate and is passed into the mixed gas intermediate storage tank for storage, thereby realizing the decoupling of the jet plasma reactor and the methanol synthesis reactor. The water flows out from the lower liquid collection pipe and is uniformly treated;

[0031] Step 4: The gas in the mixed gas intermediate storage is pressurized to 3-5 MPa by a multi-stage pressurization system and then introduced into a methanol synthesis reactor to synthesize methanol under the action of a catalyst.

[0032] Step 5: The gas-liquid mixture of methanol and unreacted gas produced after the reaction in the methanol synthesis reactor is cooled in sequence through a heat exchanger and a gas-liquid desuperheater. The cooled gas-liquid mixture is subjected to gas-liquid separation using a flash tank. The separated liquid methanol is purified by a methanol distillation tower and then sent to a methanol storage tank. A portion of the separated gas is collected after passing through the separator and then processed uniformly, and the other portion is returned to the methanol synthesis reactor for further reaction.

[0033] Compared with the background technology, the present invention has the following beneficial effects:

[0034] (1) The two-stage CO2 hydrogenation process for methanol synthesis overcomes the thermodynamic bottleneck of direct catalytic CO2 hydrogenation. CO2 is efficiently pre-activated and converted by plasma at atmospheric pressure. The resulting CO / CO2 / H2 feedstock is more kinetically and thermodynamically efficient for catalytic synthesis of methanol, thus significantly improving the overall effect.

[0035] (2) Jet plasma activates CO2 through high-energy electrons and excited-state particles at normal pressure, promoting the reverse water-gas shift reaction with H2. The reaction process does not require a catalyst, solving the problems of catalyst deactivation and high reaction temperature in traditional thermal catalytic reverse water-gas shift reactions.

[0036] (3) Flexible control of the ratio of each gas component in the product. The mass fraction of CO / CO2 / H2 in the outlet mixed gas can be changed by adjusting the power, gas flow rate and other parameters of the jet plasma reactor, thereby optimizing the selectivity and conversion rate of methanol in the catalytic section.

[0037] (5) The storage system can decouple the plasma reactor and the methanol synthesis reactor, reducing the impact of plasma reaction section fluctuations on the methanol synthesis reaction;

[0038] (6) The entire system is driven by green electricity, in which the plasma starts and stops quickly and has a fast reaction rate. It can directly adapt to the intermittent and fluctuating nature of green electricity. It has good application prospects in areas with abundant wind and solar power (such as Inner Mongolia). BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a flow chart of the green electricity consumption method of plasma-catalyzed CO2 hydrogenation to methanol according to the present invention.

[0040] FIG2 is a schematic structural diagram of the green electricity consumption system for isoplasma-catalyzed CO2 hydrogenation to methanol according to the present invention.

[0041] FIG3 is a schematic diagram of the structure of a jet plasma reactor.

[0042] Figure 4 is a schematic diagram of a multi-stage boosting system.

[0043] In Figure 2: 1. Water pump; 2. First flow controller; 3. Heat exchanger; 4. Power supply; 5. Water electrolysis hydrogen production reactor; 6. H2 storage tank; 7. First check valve; 8. Second flow controller; 9. First centrifugal pump; 10. CO2 storage tank; 11. Second check valve; 12. Third flow controller; 13. Second centrifugal pump; 14. Liquid collection pipe; 15. Jet plasma reactor; 16. Sight glass; 17. Temperature and pressure sensor; 18. Disc base; 19. Gas inlet; 20. Jet plasma reaction tower; 21. Mixed gas intermediate storage tank; 22. Third check valve; 23. Fourth flow controller; 24. Third centrifugal pump; 25. Multi-stage boosting system; 26. Catalyst; 27. Methanol synthesis reactor; 28. Gas-liquid desuperheater; 29. ​​Flash tank; 30. Separator; 31. Methanol distillation tower; 32. Methanol storage tank.

[0044] In Figure 3: 2-1, outer electrode; 2-2, inner electrode; 2-3, base.

[0045] In Figure 4: 3-1, first inlet; 3-2, gas-liquid separator; 3-3, cooling pump; 3-4, needle valve; 3-5, drying pipe; 3-6, first three-way valve; 3-7, second inlet; 3-8, second three-way valve; 3-9, first buffer tank; 3-10, diaphragm pump; 3-11, second buffer tank; 3-12, first booster pump; 3-13, first fine-tuning valve; 3-14, first back-pressure valve; 3-15, third buffer tank; 3-16, pressure-stabilizing valve; 3-17, fourth buffer tank; 3-18, second booster pump; 3-19, second fine-tuning valve; 3-20, second back-pressure valve; 3-21, fifth buffer tank. DETAILED DESCRIPTION

[0046] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0047] As shown in Figures 1 and 2, the embodiments of the present invention disclose a green electricity consumption system and method for synthesizing methanol by plasma-catalyzed CO2 hydrogenation;

[0048] The embodiment of the present invention also provides a green electricity consumption system for synthesizing methanol by plasma-catalyzed CO2 hydrogenation, which includes a reactor, a supply system, a storage and pressurization system, a power supply, and a purification and treatment system;

[0049] The reactors include a water electrolysis hydrogen production reactor 5, a jet plasma reactor 15 and a methanol synthesis reactor 27; and all the reactors are connected to a temperature monitoring device.

[0050] The water electrolysis hydrogen production reactor 5 is a solid oxide electrolysis cell (SOEC) reaction chamber with an operating temperature of 600-1000°C. Its main structure includes a cathode, an anode, and an electrolyte layer. The cathode is made of Ni / YSZ porous metal ceramic, the anode is a perovskite (ABO3) oxide containing rare earth elements, and the electrolyte layer is an oxygen ion conductor (YSZ or ScSZ, etc.);

[0051] The H2 in the water electrolysis hydrogen production reactor 5 is passed into the storage tank through the hydrogen outlet pipe for storage, and is sequentially connected to the first check valve 7, the second flow controller 8, and the first centrifugal pump 9. The oxygen outlet pipe discharges the oxygen;

[0052] As shown in FIG3 , the jet plasma reactor 15 includes a high-voltage electrode and a ground electrode to form a plasma discharge region. The jet plasma reaction tower 20 is connected to the mixed gas intermediate storage tank 21 for storing the mixed gas generated after the plasma CO2 pre-activation conversion. The jet plasma reactor includes an outer electrode 2-1, an inner electrode 2-2, a CO2 / H2 air inlet, and a base 2-3.

[0053] The outer electrode 2 - 1 and the inner electrode 2 - 2 are connected to an adjustable frequency high voltage AC power supply, which has an adjustable frequency of 5 to 40 kHz, a maximum output voltage of 20 kV, and a maximum power of 1 kW.

[0054] The outer electrode 2-1 is a hollow cylindrical structure, fixed on the base 2-3, and connected to the low voltage end of the plasma power supply;

[0055] The inner electrode 2-2 is a conical electrode, placed in the lower middle position of the hollow structure of the outer electrode 2-1, and is formed by a lower cylinder and an upper frustum. The bottom of the inner electrode 2-2 is fixed to the base 2-3 and is connected to the high voltage end of the plasma power supply through the electrode lead passing through the base 2-3. The outer wall of the inner electrode 2-2 is parallel to the inner wall of the outer electrode 2-1.

[0056] The wall of the outer electrode 2-1 is provided with an H2 / CO2 air inlet. The H2 / CO2 air inlet is located at the bottom of the reactor and is introduced tangentially from the bottom of the reactor. A rotating upward airflow is formed in the gap between the inner electrode 2-2 and the outer electrode 2-1, driving the arc between the electrodes to rotate and rise. Under the action of the tapered outlet, the plasma is ejected in the form of a jet.

[0057] Furthermore, the jet plasma reactors 15 are fixed in a symmetrical array on a disc-shaped base 18 to form reaction groups. The three reaction groups are evenly distributed at different heights on the same side of the jet plasma reaction tower 20. Three sight glasses 16 are correspondingly distributed on the other side for observing the reaction process. The top of the reaction tower is a gas collection area, and the liquid flows out from the liquid collection pipe 14 at the bottom. The wall of the reaction tower is equipped with a temperature and pressure sensor 17 to monitor the status of the reaction system in real time.

[0058] The supply system is connected to a flow control device, and the supply system includes a water vapor supply system and a CO2 supply system;

[0059] Furthermore, the water pump is used to supply water to the water vapor generating device, and the generated water vapor enters the water electrolysis hydrogen production reactor through the water vapor inlet valve and the water vapor inlet pipe; the water vapor supply system includes a water pump 1, a water vapor generating device (heat exchanger 3) and a first flow controller 2, the water pump 1 is connected to the heat exchanger 3 through the first flow controller 2 and supplies water, the heat exchanger 3 realizes heat exchange between the product methanol and the reactant water, cools the methanol and heats the water at the same time, and the generated water vapor enters the water electrolysis hydrogen production reactor 5 through the water vapor inlet valve and the water vapor inlet pipe;

[0060] The CO2 supply system is used to supply the reactant CO2, and the CO2 is mixed with H2 and passed into the isoplasmonic reactor 15 from the gas inlet 19 to supply CO2. In this embodiment, the CO2 supply system includes a CO2 storage tank 10, a second check valve 11, a third flow controller 12, and a second centrifugal pump 13.

[0061] The CO2 storage tank is used to store CO2, and the second check valve 11, the third flow controller 12, and the second centrifugal pump 13 are interconnected to control the flow of CO2;

[0062] The power supply includes a water electrolysis hydrogen production power supply 4, a jet plasma reactor power supply and a multi-stage booster system power supply, all of which are based on new energy power generation (such as photovoltaic power generation, wind power generation);

[0063] The water electrolysis hydrogen production power supply is used to power the electrochemical hydrogen evolution reaction in the water electrolysis hydrogen production reactor 5, ultimately completing the production of methanol under normal pressure conditions with the plasma jet reactor as the core. The water electrolysis hydrogen production power supply is a DC power supply device, wherein one end of the negative electrode line is connected to the hydrogen evolution electrode of the water electrolysis hydrogen production reactor 5, and the other end is connected to the negative electrode of the DC power supply; one end of the positive electrode line is connected to the oxygen evolution electrode of the water electrolysis hydrogen production reactor 5, and the other end is connected to the positive electrode of the DC power supply;

[0064] The multi-stage boosting system power supply is used to supply power to the boosting pump, solenoid valve, etc. in the multi-stage boosting system 25 .

[0065] The storage and pressurization system is used to store the CO / CO2 / H2 mixed gas produced by the jet plasma reactor and pressurize it, thereby decoupling the jet plasma reactor and the methanol reactor; it includes an intermediate storage tank 21 for the mixed gas, a third check valve 22, a fourth flow controller 23, a third centrifugal pump 24, and a multi-stage pressurization system 25;

[0066] The multi-stage boosting system boosting flow chart is shown in FIG4. The gas enters the gas-liquid separator 3-2 after entering the first inlet 3-1, and the separated liquid is discharged by the needle valve 3-4. The gas is dehydrated through the drying pipe 3-5 and then subjected to multi-stage boosting. The gas passes through the diaphragm pump 3-10 and enters the second buffer tank 3-11 from the first buffer tank 3-9 to complete the pre-stage boosting. The gas in the second buffer tank 3-11 passes through the first boosting pump 3-12 and enters the third buffer tank 3-15. If the gas in the third buffer tank 3-13 If the pressure is higher than the specified pressure, it can be released to the second buffer tank through the first back pressure valve 3-14. The second buffer tank 3-11 and the third buffer tank 3-15, together with the booster pump and the back pressure valve, realize parallel boosting. The fourth buffer tank 3-17 and the fifth buffer tank 3-21 are also parallel boosted. The four buffer tanks together complete the secondary boosting. If the pressure in the first buffer tank 3-9 is too low, it can be supplemented through the second inlet 3-7. If the pressure in the first buffer tank 3-9 is too high, it can be exhausted through the first three-way valve 3-6.

[0067] The purification system is used to separate methanol from the remaining reaction gas and purify the methanol. The gas-liquid mixture produced after the reaction in the methanol synthesis reactor is cooled in turn through the heat exchanger 3 and the gas-liquid desuperheater 28. The cooled gas-liquid mixture is separated into gas and liquid in the flash tank 29. The separated liquid methanol is purified by the methanol distillation tower 31 and stored in the methanol storage tank 32. The gas separated in the flash tank and the gas separated in the distillation tower are passed through the separator 30, and a portion is collected and processed uniformly, and the other portion is returned to the methanol synthesis reactor 27 for further reaction.

[0068] The two important reactions in the present invention (plasma CO2 pre-activation conversion and methanol catalytic synthesis) occur in two independent and isolated reaction chambers respectively, and the traditional direct thermal catalytic CO2 to methanol reaction is carried out step by step. As a plasma catalytic CO2 hydrogenation method for synthesizing methanol, the present method can carry out each step reaction under different reactors and reaction conditions during the methanol synthesis process, and can be optimized one by one to achieve the best effect of the entire reaction system; the intermediate storage system realizes the decoupling of the methanol synthesis reactor and the jet plasma reactor, so that the methanol synthesis reaction is not affected by the fluctuation of the jet plasma reactor; at the same time, plasma technology is used to partially convert CO2 into CO, and the reaction process does not require a catalyst, which solves the problems of catalyst deactivation and high reaction temperature in the traditional thermal catalytic reverse water-gas shift reaction. At the same time, the proportion of product components can be changed by regulating parameters such as gas flow rate and power; and the generated CO / CO2 / H2 raw materials are more easily and efficiently catalytically synthesized into methanol in terms of kinetics and thermodynamics, thereby achieving a significant improvement in the overall effect.

[0069] An embodiment of the present invention provides a method for consuming green electricity by plasma-catalyzed CO2 hydrogenation to synthesize methanol, comprising the following steps:

[0070] Step 1: Turn on the power supply 4 to perform the step of electrolyzing water to produce hydrogen, and the produced hydrogen is directly passed into the H2 storage tank 6 for storage;

[0071] Step 2: Open the CO2 storage tank 10 and the H2 storage tank 6, mix the gases in a ratio of 1:3 and pass them into the jet plasma reactor 15. Turn on the power to form a rotating airflow inside the mixed gas, drive the arc between the electrodes to rotate and rise, and eject the plasma in the form of a jet under the action of the gradually converging outlet. The power and air flow of each reactor are flexibly controlled in the range of 50-300W and 1-10L / min respectively, and the temperature value is monitored in real time. The CO2 pre-activation conversion is completed, and the reaction is as follows:

[0072] CO2+H2=CO+H2O

[0073] Step 3: After the reaction is completed, the mixed gas generated rises after passing through the air distribution plate and is passed into the mixed gas intermediate storage tank 21 for storage, thereby achieving decoupling of the jet plasma reaction tower 20 and the methanol synthesis reactor 27. Water flows out from the lower liquid collection pipe and is uniformly treated;

[0074] Step 4: The gas in the mixed gas intermediate storage tank 21 is pressurized to 3-5 MPa by the multi-stage pressurization system and then introduced into the methanol synthesis reactor 27 to synthesize methanol under the action of the catalyst. The specific pressurization data are as follows:

[0075] Step 5: The gas-liquid mixture of methanol and unreacted gas produced after the reaction in the methanol synthesis reactor 27 is cooled in sequence through the heat exchanger 3 and the gas-liquid desuperheater 28. The cooled gas-liquid mixture is subjected to gas-liquid separation using the flash tank 29. The separated liquid methanol is purified by the methanol distillation tower 31 and then sent to the methanol storage tank 32. The pressure of the methanol distillation tower 31 is controlled to 0.15 MPa. After passing through the separator 30, a portion of the separated gas is collected and uniformly processed, and the other portion is returned to the methanol synthesis reactor 27 for further reaction.

[0076] The above description is only a preferred embodiment of the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present invention without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation, characterized in that: It includes a jet plasma reaction tower, a methanol synthesis reactor, a supply system, a storage and pressurization system, a power supply and a purification and treatment system; The supply system is used to provide H2 and CO2 to the plasma reactor; The jet plasma reaction tower is used to pre-activate and convert CO2 using jet plasma, so that the CO2 and H2 undergo a reverse water-gas shift reaction to produce a CO / CO2 / H2 mixed intermediate product at normal pressure and low temperature; The storage and pressurization system includes a mixed gas intermediate storage tank and a multi-stage pressurization system; it is used to store and pressurize the CO / CO2 / H2 mixed gas generated by the jet plasma reactor, thereby realizing the decoupling of the jet plasma reactor and the methanol reactor; The methanol synthesis reactor is used to synthesize methanol from the mixed gas delivered by the storage and pressurization system under the action of a catalyst; The power supply is used to supply power to the plasma reactor, the formaldehyde synthesis reactor and the supply system; The purification system is used to separate methanol from the remaining reaction gas and to purify the methanol.

2. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The supply system includes a water electrolysis hydrogen production reactor, an H2 storage tank, a CO2 storage tank, a water pump, a first flow controller and a heat exchanger; wherein the water pump, the first flow controller and the heat exchanger are used to transport H2O to the water electrolysis hydrogen production reactor and control the flow, and the water electrolysis hydrogen production reactor is connected to the H2 storage tank.

3. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 2 is characterized in that: The output ends of the H2 storage tank, CO2 storage tank and mixed intermediate product storage tank are all provided with a check valve, a flow controller and a centrifugal pump.

4. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The top of the jet plasma reaction tower is a gas collection area for sending gas to the mixed gas intermediate storage tank, and the bottom is a liquid collection pipeline. Three jet plasma reaction groups are evenly arranged at different heights on the same side of the tower body. Each jet plasma reaction group contains six jet plasma reactors, which are symmetrically distributed in a hexagonal array and fixed on a disc-shaped base 18; three viewing mirrors are correspondingly distributed on the other side of the tower body for observing the reaction process, and a temperature and pressure sensor is installed on the wall of the reaction tower.

5. A green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 4, characterized in that: The isojet plasma reactor comprises an outer electrode, an inner electrode, a CO2 / H2 wind inlet and a base; The outer electrode is fixed on an insulating base and is a hollow sleeve-type electrode with a tapered outlet structure at the top; The inner electrode is a conical electrode, which is placed in the lower middle position of the outer electrode hollow structure, and is formed by a lower cylinder and an upper truncated cone. The bottom of the inner electrode is fixed on the base, and is connected to the high voltage end of the plasma power supply through an electrode lead that passes through the base. The outer wall of the inner electrode is parallel to the inner wall of the outer electrode. The wall surface of the outer electrode is provided with an H2 / CO2 wind inlet and an H2 / CO2 air flow inlet. Located at the bottom of the reaction device, it is tangentially introduced from the bottom of the reactor, forming a rotating upward airflow in the gap between the inner electrode and the outer electrode, driving the arc between the electrodes to rotate and rise, and the plasma is ejected in the form of a jet under the action of the gradually shrinking outlet; the outer electrode and the inner electrode are connected to a frequency-adjustable high-voltage AC power supply.

6. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The methanol synthesis reactor is provided with a CO / CO2 hydrogenation to methanol reaction zone and a crude methanol outlet. CO / CO2 and H2 are directionally synthesized into crude methanol at normal pressure under the catalysis of a copper-based composite nanocatalyst. The crude methanol is passed through the crude methanol outlet into a purification treatment system for purification, thereby realizing efficient chemical energy storage of abandoned electricity / valley electricity and coordinated conversion and utilization of greenhouse gas CO2.

7. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The multi-stage boosting system includes a boosting pump, a buffer tank, a back pressure valve and a real-time pressure monitoring system.

8. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The purification treatment system specifically comprises: a reheater, a gas-liquid desuperheater, a flash tank, a methanol distillation tower and a methanol storage tank connected in sequence, wherein the liquid channel of the flash tank is directly connected to the methanol distillation tower, and the gas channel is connected to the methanol synthesis reactor and the methanol distillation tower; Used to separate methanol and residual reaction gas and purify methanol.

9. The green electricity consumption system for synthesizing methanol by plasma catalytic CO2 hydrogenation according to claim 1 is characterized in that: The power supply includes a water electrolysis hydrogen production power supply, a jet plasma reactor power supply and a multi-stage boosting system power supply, which are respectively used to power the water electrolysis hydrogen production reactor, the jet plasma reactor and the multi-stage boosting system, all of which are sourced from off-grid renewable energy power generation.

10. A method for consuming green electricity by synthesizing methanol through plasma catalytic CO2 hydrogenation using the system according to any one of claims 1 to 9, characterized in that: The method includes: Step 1, turn on the power supply to perform the step of electrolyzing water to produce hydrogen, and the produced hydrogen is directly passed into the H2 storage tank for storage; Step 2: Open the CO2 storage tank and the H2 storage tank, mix the gases in a certain proportion and pass them into the jet plasma reactor, turn on the power supply to form a rotating airflow inside the mixed gas, drive the arc between the electrodes to rotate and rise, and the plasma is ejected in the form of a jet under the action of the gradually shrinking outlet. The power and air intake flow of a single reactor are flexibly adjusted, and the temperature value is monitored in real time; the CO2 pre-activation conversion is completed, and the reaction is as follows: CO2+H2=CO+H2O Step 3: After the reaction is completed, the mixed gas generated rises after passing through the air distribution plate and is passed into the mixed gas intermediate storage tank for storage, thereby realizing the decoupling of the jet plasma reactor and the methanol synthesis reactor, and the water flows out from the lower liquid collection pipe and is uniformly treated; Step 4: The gas in the mixed gas intermediate storage is pressurized to 3-5 MPa by a multi-stage pressurization system and then introduced into a methanol synthesis reactor to synthesize methanol under the action of a catalyst. Step 5: The gas-liquid mixture of methanol and unreacted gas produced after the reaction in the methanol synthesis reactor is successively subjected to heat exchange The gas-liquid mixture after cooling is separated into gas and liquid by a flash tank. The separated liquid methanol is purified by a methanol distillation tower and then sent to a methanol storage tank. The separated gas passes through a separator, a part of which is collected and processed uniformly, and the other part is returned to the methanol synthesis reactor for further reaction.

Images