A photo-energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas

Abstract

The present invention belongs to the field of carbon neutrality technology, and discloses a system for continuous electrolysis of molten salt containing carbon dioxide and sulfur dioxide flue gas using light energy. The photothermal module is used to heat the electrolytic molten salt so that the electrolytic molten salt reaches the required temperature for electrolysis of SO2 and CO2; the photoelectric module is used to obtain the electric energy required for SO2 and CO2, and to maintain the electric energy required for the operation of the molten salt electrolysis SO2 and CO2 equipment; the molten salt continuous electrolysis device is used to grind the generated sulfur-containing carbon into powder, and to add a sulfur-containing carbon powder filtering and collection device to filter and collect the carbon powder floating on the hot molten salt to obtain high-value-added sulfur-containing carbon. The photothermal module of the present invention adopts a dish-type solar concentrator plus a molten salt storage tank, which occupies less space and is flexible in layout compared to other methods; the molten salt continuous electrolysis device of the present invention integrates multiple functions, so that the structure can realize the continuous electrolysis of CO2 and SO2 and collect the high-value-added sulfur-containing carbon powder generated, realizing the requirements of fully automatic production.

Description

Technical Field

[0001] The present invention belongs to the field of carbon neutrality technology, and in particular relates to a system for continuous photoelectrolysis of molten salt containing carbon dioxide and sulfur dioxide flue gas. Background Art

[0002] Currently, with the advancement of modern industrialization, the massive consumption of fossil energy has led to a sharp increase in carbon dioxide emissions, triggering a serious greenhouse effect. Carbon dioxide is composed of carbon atoms and oxygen atoms, has high thermal stability, and relatively stable chemical properties, making it generally difficult to decompose. Currently, there are several main methods for achieving the chemical conversion of CO2. The first is photocatalysis, which mainly simulates photosynthesis and uses photocatalysts to generate electron-hole pairs under sunlight. After the electron-hole pairs separate, the photogenerated electrons reduce CO2 to hydrocarbon mixtures such as CO or methane. However, photocatalysis is still in the experimental stage and has disadvantages such as low photoelectric catalytic conversion efficiency, low reaction rate, and high reaction energy consumption.

[0003] The second method is electrocatalysis. Electrocatalysis is divided into three methods according to the different electrolytes: ionic liquid medium, normal temperature aqueous solution medium and high temperature molten salt medium. The principle of the ionic liquid medium method is: using The following liquid, which is composed entirely of ions, will Synthesize carbon products, but the ion solution used in this method is expensive. The principle of the normal temperature aqueous solution medium method is: water will Converted to hydrated state , and then an adsorption state is generated on the electrode , and then generates , formic acid and other carbon products, but due to The low solubility in water and the hydrogen evolution reaction during water electrolysis result in low carbon product yields.

[0004] In the high-temperature molten salt medium method, high-temperature molten salt refers to a molten liquid composed of inorganic anions and inorganic cations under high temperature conditions. Molten salts have the advantages of many types, wide temperature range, good stability, good solubility, wide potential window, high conductivity, high heat capacity, and no solvent process. In high-temperature molten salts, CO2 can be electrolyzed into products such as C and CO. Depending on the type of molten salt used, the electrolysis temperature, and the cathode material, carbon products of different forms can be obtained. For example, the Groult team used a ternary Li2CO3-Na2CO3-K2CO3 molten salt system, with nickel sheets as cathodes, graphite rods, and gold sheets as anodes, and conducted constant potential electrolysis experiments at 450-700 ° C, obtaining a specific surface area of ​​up to 1315m 2 / g of carbon powder. Novoselova et al., using a GC working electrode, a Pt counter electrode, and a quasi-reference electrode at a reaction temperature of 550°C in a NaCl-KCl-CsCl molten salt, performed constant potential and constant current electrolysis, yielding carbon nanotubes after electrochemical reduction. Molten salt electrolysis is highly efficient in decomposing carbon dioxide and can produce high-value-added carbon, but the electrolysis and molten salt heating require significant electricity.

[0005] Sulfur dioxide, also known as sulfurous anhydride, is the most common sulfur oxide. It is colorless and has a strong pungent odor. Sulfur dioxide is one of the important causes of acid rain, which can lead to soil acidification, induce plant diseases and pests, and even endanger human health.

[0006] Therefore, how to achieve atmospheric sulfur reduction is crucial. Currently, there are several ways to reduce sulfur dioxide emissions: using low-sulfur fuel, but its source is difficult and expensive; desulfurization during the combustion process, but the desulfurization efficiency is low and the flue gas still needs to be purified. The other is flue gas desulfurization, which is also the most effective and main treatment method. This device uses innovative molten salt electrolysis technology. Through the molten salt electrolysis process, high concentrations of sulfur dioxide in the flue gas can be removed. and Converted into sulfur-containing carbon, generated at the cathode or It combines with carbon to form sulfur-containing carbon, which can be used to absorb mercury in flue gas.

[0007] Through the above analysis, the problems and defects of the existing technology are as follows:

[0008] (1) The existing technology consumes a lot of energy.

[0009] (2) The existing technology does not treat flue gas containing both CO2 and SO2 to obtain high value-added sulfur-containing carbon materials.

[0010] (3) The existing technology has large heat loss in the pipeline, is easy to be polluted, and the continuous electrolysis effect is poor, resulting in low system operation efficiency. Summary of the Invention

[0011] In response to the problems existing in the prior art, the present invention provides a system for continuously electrolyzing molten salts of flue gas containing carbon dioxide and sulfur dioxide using light energy. Specifically, it relates to a system for continuously electrolyzing molten salts of flue gas containing carbon dioxide and sulfur dioxide using comprehensive light energy.

[0012] The present invention is implemented as follows: a photothermal continuous electrolysis system for flue gas containing carbon dioxide and sulfur dioxide comprises three parts: a photothermal module, a photovoltaic module, and a molten salt continuous electrolysis device. The molten salt continuous electrolysis device can be divided into an electrolysis mechanism, a grinding mechanism, an electrolysis molten salt circulation mechanism, a gas treatment mechanism, and a shell temperature control system. The photothermal module uses dish-type solar energy concentration to heat the heat storage molten salt, and the hot heat storage molten salt module exchanges heat with the cold electrolysis molten salt flowing out of the molten salt continuous electrolysis device through a heat exchanger, so that the electrolysis molten salt can reach the working temperature required for electrolysis after flowing back to the electrolysis device through heat exchange; the photovoltaic module supplies the electricity required for electrolysis, temperature control and pumping of molten salt through photovoltaic power generation; the flue gas to be treated is passed into the molten salt continuous electrolysis device to be and Electrolysis produces sulfur-containing carbon and O2. The carbon attached to the cathode disc is ground by a grinding device and then turned into sulfur-containing carbon powder floating on the electrolytic molten salt. It can then be collected and processed by a sulfur-containing carbon powder collection device.

[0013] Furthermore, the photothermal module includes a plurality of dish-type dual-axis tracking concentrators, which are equipped with a corresponding number of heat absorbers.

[0014] Furthermore, the solar thermal module includes a casing main pipe consisting of a hot thermal storage molten salt pipe and a cold thermal storage molten salt pipe (the hot molten salt flows in the inner pipe, and the cold molten salt flows between the inner pipe and the outer pipe) and casing branches, wherein the casing main pipe is divided into various casing branches, which are connected to the dish-type heat absorber.

[0015] Furthermore, the photothermal module includes a hot molten salt storage tank and a cold molten salt storage tank, the hot molten salt storage tank input port is connected to the hot thermal storage molten salt casing main pipeline, and the cold molten salt storage tank input port is connected to the hot thermal storage molten salt casing main pipeline.

[0016] Furthermore, the photothermal module includes two molten salt pumps, which are respectively connected to the output ports of the hot molten salt storage tank and the cold molten salt storage tank.

[0017] Furthermore, the photothermal module includes a heat exchanger located between the molten salt pump of the hot molten salt storage tank and the cold molten salt storage tank. The hot thermal storage molten salt flows in at high temperature and flows out after heat exchange into cold thermal storage molten salt.

[0018] Furthermore, the photovoltaic module includes a solar charging module, a battery, and a controller. The charging module is connected to the battery and converts solar energy directly into electrical energy, which is stored in the battery. The battery is connected to the controller, which is connected to a thermocouple and a molten salt pump. The controller controls the operating condition of the molten salt pump by monitoring the temperature of the electrolyzed molten salt in the molten salt continuous electrolysis device, thereby controlling the flow rate of the thermal storage molten salt involved in heat exchange and the flow rate of the hot thermal storage molten salt entering the insulation jacket.

[0019] Furthermore, the electrolysis mechanism includes a cathode disc and an anode disc located in the crucible body, a brush located inside the cathode disc, an electrode connected to the anode disc, a sleeve fixed on the crucible cover consisting of a cathode inner tube and an anode outer tube, a cathode wire and an anode wire located in the cathode inner tube and the anode outer tube and connected to the brushes and the cathode, and a battery connected to the wires.

[0020] Furthermore, the grinding mechanism includes a controller and a motor located outside the crucible body, a sliding channel installed on the crucible cover, a piston located in the sliding channel, a crankshaft connected to the piston and the motor, a cross grinding fixture connected to the cathode inner tube, and a friction connecting rod connected to the piston and the cathode disc. Furthermore, the crankshaft and the piston, and the connecting rod and the cathode disc are all connected by fixing pins, and a sealing device is provided between the piston and the sliding channel.

[0021] Furthermore, a cold electrolysis molten salt outlet is provided in the middle of the shell and the crucible body side wall, a hot electrolysis molten salt inlet is provided at the lower part of the shell and the crucible body side wall, and a gas inlet and a gas outlet are provided at the upper part of the shell and the crucible body side wall.

[0022] Furthermore, the electrolytic molten salt circulation mechanism includes an electrolytic molten salt pipeline connecting the hot electrolytic molten salt inlet and the cold electrolytic molten salt outlet. Furthermore, the inlet and the pipeline are both provided with sealing devices for sealing to prevent leakage of the molten salt.

[0023] Furthermore, the electrolytic molten salt circulation mechanism includes a carbon powder filtering and collecting device near the outlet of the cold electrolytic molten salt, two molten salt pumps, a heat exchanger, and a hot electrolytic molten salt storage tank. Furthermore, the cold electrolytic molten salt flows into the heat exchanger, and the hot electrolytic molten salt flows out of the heat exchanger.

[0024] Furthermore, the gas treatment mechanism includes a flue gas inlet pipe connected to the gas inlet, a tail gas outlet pipe connected to the gas outlet, a flue gas treatment device near the gas inlet, and a tail gas treatment device near the gas outlet.

[0025] Furthermore, the insulation sleeve is a cylindrical annular cavity, and hot molten salt is introduced into the cylindrical annular cavity. The diameter of the upper cylindrical ring is larger than the diameter of the lower cylindrical ring. An inlet and an outlet are set on the upper cylindrical ring. The hot molten salt medium flows into the cavity from the inlet and then flows out from the outlet, thereby achieving the purpose of insulation.

[0026] Furthermore, the heat-insulating sleeve is outside the crucible and is supported on the upper edge of the shell.

[0027] Furthermore, the thermocouple is connected to the controller and passes through the through hole of the crucible cover and is suspended in the electrolytic molten salt of the crucible body, and a sealing device is provided at the through hole.

[0028] Furthermore, the shell temperature control system includes a thermal insulation sleeve, a controller and a thermocouple.

[0029] Another object of the present invention is to provide a method for continuously electrolyzing molten salts from flue gas containing carbon dioxide and sulfur dioxide using the system for continuously electrolyzing molten salts from flue gas containing carbon dioxide and sulfur dioxide using light energy, wherein the method comprises:

[0030] Step 1: The dish-type dual-axis tracking concentrator in the thermal module automatically tracks the sun, heating the heat storage molten salt in the absorber. The heated molten salt enters the hot molten salt storage tank through the hot heat storage molten salt pipeline. The molten salt in the hot molten salt storage tank 24 is controlled by the shell temperature control system composed of a thermocouple and a controller. After being pressurized by the molten salt pump, part of it flows to the insulation jacket, and part flows to the heat exchanger to exchange heat with the cold electrolysis molten salt.

[0031] Step 2: The solar charging module in the photovoltaic module absorbs solar energy to generate electricity and stores it in the battery to supply the power required for the controller, motor, molten salt pump, and electrolysis;

[0032] Step 3: During electrolysis, the molten salt pump on the side of the electrolysis molten salt storage tank is turned on to press the liquid cold electrolysis molten salt into the heat exchanger. After heat exchange with the hot thermal storage molten salt, it enters the electrolysis molten salt storage tank and is pressurized by the molten salt pump before entering the crucible body from the hot electrolysis molten salt outlet.

[0033] Step 4: Flue gas is introduced into the flue gas inlet pipe, dust and moisture are absorbed by the flue gas treatment device, and then introduced into the electrolytic molten salt;

[0034] Step 5: Turn on the motor and rotate the crankshaft to make the piston slide up and down in the movable channel on the crucible cover, driving the friction connecting rod to grind the cathode disc on the one hand and rotate the cathode disc in the cross grinding fixture on the other hand, thereby stirring the electrolytic molten salt and promoting the reaction. The cross grinding fixture grinds away the carbon generated on the other side of the cathode disc during rotation, promoting the continuous reaction.

[0035] Step 6: The ground carbon powder floats on the surface of the electrolytic molten salt and is removed in a carbon powder filtration and collection device after the electrolytic molten salt flows out of the cold electrolytic molten salt outlet. At the same time, the exhaust gas is passed through the exhaust gas outlet pipe to the exhaust gas treatment device and discharged into the atmosphere after treatment.

[0036] Step seven: When electrolysis is suspended, the hot electrolytic molten salt inlet is closed, and the electrolytic molten salt in the pipeline is pressurized by the molten salt pump and stored in two electrolytic molten salt storage tanks for insulation; after the system stops running, high-value-added carbon is obtained by the carbon powder filtering and collecting device.

[0037] Furthermore, after the heat exchange in step 1 is completed, the cold thermal storage molten salt flows to the cold thermal storage molten salt storage tank.

[0038] Another object of the present invention is to provide an industrial carbon dioxide and sulfur dioxide flue gas removal device, which is equipped with the light energy continuous electrolysis system for molten salt of flue gas containing carbon dioxide and sulfur dioxide.

[0039] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0040] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving these problems, this paper closely combines the technical solutions to be protected by the present invention and the results and data during the research and development process, and analyzes in detail and in depth how the technical solutions of the present invention solve the technical problems and some creative technical effects brought about by solving the problems. The specific description is as follows:

[0041] There are many methods on the market for treating deposits on electrode materials, such as ultrasonic-assisted treatment, mechanical stirring, and vacuum distillation. However, these methods have their own shortcomings.

[0042] 1. Ultrasonic assisted treatment: Generally speaking, ultrasonic cavitation effect is best at 50°C~60°C. Cleaning agent is not more effective as the temperature is higher. It may lose effectiveness at high temperature. Usually, the cleaning effect of ultrasonic wave is deteriorated when the temperature exceeds 85°C. Therefore, in actual application of ultrasonic cleaning, the working temperature is 50°C~70°C. However, in our treatment, high temperature molten salt of 600°C is used, so ultrasonic cleaning cannot play a role.

[0043] 2. Mechanical Agitation: Agitating the liquid by rotating an agitator in a mixing tank is a common method for dispersing gases, liquids, or solid particles in a liquid in chemical production. Agitation is the process of stirring materials to cause a certain type of circulation, thereby achieving uniform mixing or accelerating physical or chemical processes. It involves the interdispersion of two or more materials in motion. However, in this experiment, low stirring speeds resulted in poor separation of the carbon powder and minimal concentration polarization during the electrolysis process, making the use of mechanical agitation unnecessary. Excessive stirring speeds can create vortices in the molten salt, which, due to centrifugal forces and other effects, can affect electrolysis efficiency.

[0044] 3. Vacuum distillation: This method is performed under reduced pressure and is generally used to separate substances that readily decompose when heated to their boiling point at atmospheric pressure. It can also be combined with other distillation methods (such as steam distillation) to lower the distillation temperature and improve separation efficiency. However, this method is not suitable for this experiment because of the need to achieve continuous electrolysis, protect the electrode material, and obtain high-value-added carbon.

[0045] The solution to this problem, proposed in this article, involves designing a grinding mechanism. The grinding mechanism includes a controller, an electric motor, a sliding channel mounted on the crucible lid, a piston located in the sliding channel, a crankshaft connected to the piston and the electric motor, a cross-shaped grinding fixture connected to the cathode inner tube, and a friction link connected to the piston and the cathode disc. The grinding mechanism has two main functions: first, to fix the center of the cathode disc, and second, to rotate the disc and scrape off the sulfur-containing carbon. In the grinding mechanism, the cross-shaped grinding fixture is fixed by the cathode inner tube. The cross-shaped grinding fixture holds the cathode disc in place, allowing it to rotate within the cross-shaped grinding fixture while the cross-shaped grinding fixture remains stationary, fixing the center of the cathode disc. The friction link is connected to the cathode disc via a fixed pin. The upward and downward movement of the piston drives the friction link, which in turn rotates the cathode disc. During the electrolysis process, sulfur-containing carbon is produced on the surface of the cathode disk. The friction link and cross-grinding fixture are both coated with coarse abrasives on their surfaces in contact with the cathode disk. The relative motion of the cathode disk, the friction link, and the cross-grinding fixture grinds the sulfur-containing carbon on the cathode surface into a powder, freeing it from the cathode disk. For each revolution of the friction link, the surface of the disk in contact with the friction link is ground once, and the surface in contact with the cross-grinding fixture is ground four times. To prevent leakage or short circuits, the coarse abrasives and retaining pins in contact with the cathode disk are made of high-temperature insulating materials. To power the rotating cathode disk, brushes extend into the cathode disk through the cathode inner tube. A sealed insulation device is installed at the connection between the cathode inner tube and the cathode disk to prevent high-temperature molten salt from penetrating and corroding the brushes, and to prevent the cathode disk from conducting electricity to the cathode inner tube. Research indicates that because carbon deposits on the electrodes affect the cell pressure between the two stages, the cell pressure between the two stages changes as the electrolysis process produces deposited carbon. When the cell pressure is low, the sulfur-containing carbon is relatively fluffy, requiring only a small torque from the friction link to shave it off. When the cell pressure rises to a certain temperature, the sulfur-containing carbon becomes compacted, requiring a large torque from the friction link to shave it off. After the cell pressure rises to a certain temperature, the sulfur-containing carbon becomes fluffy again. Therefore, the torque required for the friction link to grind the sulfur-containing carbon can be calculated based on the measured cell pressure. At a constant cell pressure, the accumulation of sulfur-containing carbon on the cathode disk accelerates as the molten salt temperature rises. Therefore, the motion cycle of the friction link can be adjusted based on the measured molten salt temperature. After sensors measure the cell pressure and molten salt temperature of the electrolysis unit, they transmit this data to a controller, which controls the engine and crankshaft to provide the appropriate torque and motion cycle for the friction link. Experimental data confirms that the slow rate of carbon production, coupled with the cross-grinding fixture and friction link, allows for the timely separation of the cathode material from the carbon powder, resulting in 100% pure cathode material. This not only increases electrolysis efficiency but also allows for the timely collection of carbon powder from the molten salt using the carbon powder separation device.

[0046] Considering the relatively small total mass of carbon produced during the experiment, the loosening of deposited carbon during the electrolysis process (after the experiment, the molten salt changed from a colorless, transparent liquid to a liquid with floating black matter), and the subsequent loss of carbon products due to multiple cleaning processes, the calculated current efficiency should be lower than the actual current efficiency. However, if the aforementioned grinding scheme is adopted, the gap between the calculated and actual current efficiencies can be narrowed, thereby improving the actual efficiency.

[0047] At high temperatures, the carbon product forms an increasingly dense pile due to the increasing temperature of the molten salt, which reduces its viscosity and accelerates ion movement. At a molten salt temperature of 600°C and a cell voltage of 2.8V, the flaky carbon stacks form a prismatic tubular structure with a width of approximately 1μm and a thickness of 60nm. The resulting carbon product has a specific surface area of ​​687.15m²g⁻¹. Therefore, to maintain the electrolysis reaction and improve electrolysis efficiency, the grinding device designed in this paper can effectively solve the above problems.

[0048] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0049] In the system for the comprehensive utilization of light energy to continuously electrolyze molten salt containing carbon dioxide and sulfur dioxide, the dish-type photothermal molten salt module is used to heat the electrolytic molten salt so that the electrolytic molten salt reaches the electrolysis temperature. and The required temperature is replaced by the traditional method of heating molten salt with electric energy. At the same time, the present invention uses the photovoltaic module to obtain the electrolysis and The required electricity, as well as the electricity required to maintain the operation of the controller, motor, and molten salt pump, greatly reduces the consumption of traditional electricity for molten salt electrolysis of carbon dioxide and sulfur dioxide, and realizes the use of clean energy to reduce emissions. and On the one hand, it reduces the smoke and On the other hand, it can also produce high value-added sulfur-containing carbon and oxygen. In addition, this system can also be used to treat flue gas containing CO2 and NO to obtain high value-added nitrogen-containing carbon materials.

[0050] The solar thermal module of the present invention utilizes a dish-type solar concentrator coupled with a molten salt storage tank. Compared to other methods, this approach occupies a smaller footprint and offers flexible layout. It can heat the molten salt to a relatively high temperature, meeting the requirements of raising the electrolytic molten salt to operating temperature and maintaining continuous operation under heat exchange conditions. Furthermore, the molten salt pipeline of the solar thermal module of the present invention utilizes a sleeve-type design, with hot molten salt in the inner tube and cold molten salt in the outer tube between the inner and outer tubes, effectively reducing heat loss in the pipeline and improving system operating efficiency.

[0051] The molten salt continuous electrolysis device of the present invention adds a grinding mechanism and a carbon powder filtration and collection device to the electrolysis mechanism. The grinding mechanism uses a motor to drive the cathode turntable to rotate. The carbon generated on the cathode turntable is ground into carbon powder by a cross grinding fixture and friction connecting rod. The carbon powder floats on the hot molten salt. The molten salt is filtered and collected by the carbon powder filtration and collection device to collect the high-value-added carbon, while avoiding contamination of the pipeline and promoting continuous electrolysis. Furthermore, a housing temperature control system is added to ensure that the electrolysis is carried out at the required electrolysis temperature.

[0052] Third, as auxiliary evidence for the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0053] The expected benefits and commercial value of the technical solution after conversion are as follows: Taking the flue gas from a typical 1000MW large-scale coal-fired power plant as an example, the flue gas flow rate is 3190t / h. The flue gas from a coal-fired power plant includes CO2, N2, H2O, nitrogen oxides, sulfides, and smoke dust. Considering only the main components of the flue gas, the specific components are shown in the following table:

[0054]

[0055] Calculations show that a 1000MW large-scale coal-fired power plant emits an average of 617 tons of carbon dioxide per hour. Using molten salt catalytic electrolysis for CO2, assuming the system of the present invention absorbs all carbon dioxide with an 80% removal rate, 493.6 tons of carbon dioxide can be removed per hour. Considering the current efficiency of carbon powder production, which is 75%, but taking into account the actual loss current efficiency, which is 35%, approximately 47.1 tons of carbon powder can be produced per hour. At 600°C and a cell voltage of 3.8V, the average energy consumption for electrolyzing carbon dioxide per kg of carbon powder is 95.96 kWh. Based on the industrial electricity price of 1 yuan per kilowatt-hour, the hourly electricity cost of electrolysis using traditional electric energy is 4.52 million yuan. Coal-fired power plants, steel smelters, and other factories are basically unable to afford such high costs for carbon dioxide treatment. Today, the present invention uses light energy to completely replace traditional electricity, making low-cost molten catalytic electrolysis of CO2 possible. Manufacturers only need to bear the initial equipment purchase and assembly costs and the subsequent maintenance and repair costs. On the other hand, the system of the present invention utilizes Li-Na-K ternary carbonate molten salt to absorb CO2 and generate industrial amorphous carbon. Based on the market purchase price of 5 yuan per kg of industrial amorphous carbon, and taking a 1000MW large coal-fired flue gas plant as an example, full load operation (24 hours) can produce amorphous carbon worth 56.52 million yuan a day, which has huge commercial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of a system for continuous photoelectrolysis of molten salt containing carbon dioxide and sulfur dioxide flue gas provided by an embodiment of the present invention;

[0057] Figure 2 Schematic diagram of a molten salt continuous electrolysis device in a molten salt system for continuous electrolysis of flue gas containing carbon dioxide and sulfur dioxide using light energy provided by an embodiment of the present invention;

[0058] Figure 3 is a schematic diagram of a housing temperature control system provided by an embodiment of the present invention;

[0059] Figure 4 is a schematic diagram of a photovoltaic module provided by an embodiment of the present invention;

[0060] Figure 5 is a schematic diagram of a gas processing mechanism provided by an embodiment of the present invention;

[0061] Figure 6 Schematic diagram of an electrolytic molten salt circulation mechanism provided by an embodiment of the present invention;

[0062] Figure 7 is a schematic diagram of an electrolysis mechanism provided by an embodiment of the present invention;

[0063] Figure 8 Schematic diagram of a photothermal module provided by an embodiment of the present invention;

[0064] Figure 9 is a schematic diagram of a grinding mechanism provided by an embodiment of the present invention;

[0065] FIG10 is an it diagram corresponding to different voltages of 500 mA h at 450°C, 525°C and 600°C provided by an embodiment of the present invention; Figure 10a It curves corresponding to different cell pressures at a molten salt temperature of 450°C. Figure 10b It is the corresponding it curve when the molten salt temperature is 525℃; Figure 10c This is the current diagram when the molten salt temperature is 600℃ and the cell voltage is 2.8V;

[0066] Figure 11 This is an electron diagram of the cathode product after cooling at 600°C under different cell pressures provided by an embodiment of the present invention;

[0067] Figure 12 1 is a graph showing the current efficiency of carbon products prepared at different temperatures and different cell pressures according to an embodiment of the present invention;

[0068] Figure 13 This is an energy consumption diagram corresponding to the carbon products prepared at different temperatures and different tank pressures provided by the embodiment of the present invention;

[0069] Figure 1: 1. Hot thermal storage molten salt pipeline; 2. Cold thermal storage molten salt pipeline; 4. Cold thermal storage molten salt storage tank; 5. Heat exchanger; 6. Electrolysis molten salt pipeline; 7. Hot electrolysis molten salt inlet; 8. Electrolysis molten salt storage tank; 9. Cold electrolysis molten salt outlet; 10. Insulation sleeve; 11. Carbon powder filtration and collection device; 12. Shell; 13. Flue gas inlet pipeline; 14. Molten salt continuous electrolysis device; 15. Flue gas treatment device; 16. Exhaust gas treatment device; 17. Motor; 18. Exhaust gas outlet pipeline; 19. Piston; 20. Controller; 21. Crankshaft; 22. Battery; 23. Solar charging module; 24. Hot molten salt storage tank ; 25. Heat absorber; 26. Dish-type dual-axis tracking concentrator; 27. Thermal storage molten salt; 28. Cathode disc; 29. ​​Anode disc; 30. Anode outer tube; 31. Cathode inner tube; 32. Crucible body; 33. Crucible cover; 34. Anode wire; 35. Cathode wire; 36. Cross grinding fixture; 37. Bolt; 38. Brush; 39. Friction link; 40. Thermocouple; 41. Fixing pin; 42. Electrolytic molten salt; 301. First molten salt pump; 302. Second molten salt pump; 303. Third molten salt pump; 304 Fourth molten salt pump; 801. First electrolytic molten salt storage tank; 802. Second electrolytic molten salt storage tank. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0071] 1. In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an explanatory embodiment that expands on the technical solution of the claims.

[0072] like Figure 1-Figure 2As shown, the present invention provides a system for continuously electrolyzing flue gas containing carbon dioxide and sulfur dioxide into molten salt using light energy, including three parts: a photothermal module, a photovoltaic module, and a continuous electrolysis device. The continuous electrolysis device also includes an electrolysis mechanism, a grinding mechanism, an electrolysis molten salt circulation mechanism, a gas treatment mechanism, and a shell temperature control system. During use, flue gas is discharged into the flue gas inlet pipe 13, and the battery 22 supplies power to generate carbon products and oxygen on the cathode disk 28 and the anode disk 29, respectively. Then, the controller 20 controls the motor 17 to drive the friction link 39 to rotate the cathode disk 28. The relative movement between the cathode disk 28, the friction link 39, and the cross grinding fixture 36 grinds the carbon products generated on the cathode disk 28 into carbon powder. When the molten salt flows out of the molten salt continuous electrolysis device 14 through the cold electrolysis molten salt outlet 9, the carbon powder floating on the surface of the molten salt is carried out of the electrolysis device and separated from the electrolysis molten salt 42 by the carbon powder filtering and collecting device 11 on the electrolysis molten salt pipeline 6. The solar thermal module provides the required temperature for electrolysis, while the photovoltaic module provides energy for the electrolysis of carbon dioxide and sulfur dioxide and the control system. Using the solar thermal module for heat and the photovoltaic device for power, the molten salt continuous electrolysis unit 14 electrolyzes carbon dioxide and sulfur dioxide in the flue gas. The cathode disk 28 is then driven to rotate, grinding the carbon products into carbon powder, enabling the system to operate continuously to produce carbon powder. This device is environmentally friendly and energy-saving, highly automated, highly adaptable, and easy to operate, enabling the continuous electrolysis of carbon dioxide and sulfur dioxide to produce carbon powder using clean solar energy.

[0073] According to a preferred embodiment of the present invention, in the electrolysis mechanism, the molten salt continuous electrolysis device 14 is powered by a photoelectric module, and the temperature of the electrolyzed molten salt 42 is detected by a thermocouple 40 to output a signal to the controller 20 to control the discharge of the battery 22, so as to control the working load of the molten salt continuous electrolysis device 14. The battery 22 supplies power to the cathode disk 28 through the cathode wire 35 in the cathode inner tube 31 connected to the brush 38, and the battery 22 supplies power to the anode disk 29 through the anode wire 34 in the anode outer tube 30. At the same time, the connection points are connected with sealing devices. This connection method can effectively protect the transmission line from being damaged by the molten salt, and the brush 38 can effectively supply power to the rotating cathode disk 28.

[0074] According to a preferred embodiment of the present invention, in the grinding mechanism, the molten salt continuous electrolysis device 14 drives the rotation of the cathode disc 28 through the movement of the friction link 39, and at the same time uses the friction surface of the friction link 39 to grind the carbon generated on the side of the cathode disc 28 close to the link into carbon powder. The molten salt continuous electrolysis device 14 fixes the cross grinding fixture 36 through the cathode inner tube 31, and fills the space between the cathode inner tube 31 and the cross grinding fixture 36 with an insulating seal to prevent the molten salt from entering the interior of the cathode inner tube 31 and contacting the brush 38. The cross grinding fixture 36 is used for fixing and the friction link 39 is used for driving, so that the cathode disc 28 is fixed during rotation and the carbon generated on the side of the cathode disc 28 close to the cross grinding fixture is ground into carbon powder by the cross grinding fixture 36. The operation is simple and the automation is high.

[0075] According to a preferred embodiment of the present invention, in the electrolytic molten salt circulation mechanism, the hot electrolytic molten salt inlet 7 is above the cold electrolytic molten salt outlet 9. Since the hot molten salt is relatively light, it is conducive to the diffusion of the hot molten salt from the bottom to make the molten salt temperature uniform. The cold electrolytic molten salt outlet 9 is at the molten salt liquid surface, so that the carbon powder can flow out of the continuous electrolysis device 14 together with the cold molten salt. Thereafter, the carbon powder is separated from the molten salt in the carbon powder filtration and collection device on the electrolytic molten salt pipeline 6. After the carbon powder is separated from the cold molten salt, it flows through the heat exchanger 5 and is reheated into hot molten salt. By providing an electrolytic molten salt storage tank, the electrolytic molten salt can remain in the electrolytic molten salt storage tank when the system stops, and the provision of two electrolytic molten salt storage tanks can separate the speeds of the electrolytic molten salt flowing through the continuous electrolysis device 14 and the heat exchanger 5.

[0076] The molten salt 42 can be stored in an electrolytic molten salt storage tank. By setting up two electrolytic molten salt storage tanks, the flow rates of the electrolytic molten salt 42 in the pipelines of the heat exchanger 5 and the molten salt continuous electrolysis device 14 can be independent of each other and reach the optimal value for maintaining the working temperature of the electrolytic molten salt.

[0077] The present invention has no particular limitation on the gas processing mechanism, as long as the gas processing mechanism can pre-process the input flue gas and process the tail gas. Figure 1 As shown, the gas treatment mechanism includes a flue gas inlet pipe 13 inserted into the molten salt, a flue gas treatment device 15 located in the flue gas inlet pipe 13, an exhaust gas outlet pipe 18, and an exhaust gas treatment device 16 located in the exhaust gas outlet pipe 18. The flue gas treatment device 15 pre-treats the incoming flue gas to absorb impurities such as fly ash and water in the flue gas. The exhaust gas treatment device 16 removes any harmful gases that have not been completely removed from the exhaust gas and prevents the escape of molten salt vapor.

[0078] According to a preferred embodiment of the present invention, Figure 3 is a schematic diagram of a housing temperature control system provided by an embodiment of the present invention; Figure 4 is a schematic diagram of a photovoltaic module provided by an embodiment of the present invention; Figure 5is a schematic diagram of a gas processing mechanism provided by an embodiment of the present invention; Figure 6 Schematic diagram of an electrolytic molten salt circulation mechanism provided by an embodiment of the present invention; Figure 7 is a schematic diagram of an electrolysis mechanism provided by an embodiment of the present invention; Figure 8 Schematic diagram of a photothermal module provided by an embodiment of the present invention; Figure 9 Schematic diagram of a grinding mechanism provided in an embodiment of the present invention.

[0079] The present invention does not specifically limit the housing temperature control system; it only needs to reduce the heat dissipated by the molten salt continuous electrolysis device 14 to the outside world. Preferably, the housing temperature control system consists of a housing 12 encasing the outermost layer of the molten salt electrolysis device 14, a crucible body 32 containing the electrolyzed molten salt, an insulation jacket 10 positioned between the housing 12 and the crucible body 32, and a crucible cover 33 positioned above the molten salt continuous electrolysis device 14. By passing the thermally regenerative molten salt through the insulation jacket 10, the molten salt in the molten salt continuous electrolysis device 14 is further heated, reducing heat loss. The crucible body 32 and the crucible cover 33 are connected by bolts 37, facilitating opening and closing of the crucible cover during maintenance. The crucible body 32, the crucible cover 33, and the housing 12 are all constructed of insulating material to reduce the heat dissipated by the molten salt continuous electrolysis device 14 to the outside world. Furthermore, the crucible cover 33 is connected to a thermocouple 40, a piston 19, an anode outer tube 31, and other components, providing support for the device.

[0080] The present invention has no particular limitation on the photothermal module. The photothermal module only needs to absorb solar energy to heat the molten salt continuous electrolysis device 14 and store a portion of the energy to provide energy for insufficient solar energy. Preferably, the photothermal module includes a heat absorber 25, a dish-type dual-axis tracking concentrator 26 connected to the heat absorber 25, a hot thermal storage molten salt pipeline 1 and a cold thermal storage molten salt pipeline 2 connected to the heat absorber 25, a thermal storage molten salt 27 flowing in the hot thermal storage molten salt pipeline 1 and the cold thermal storage molten salt pipeline 2, a hot molten salt storage tank 24 connected to the hot thermal storage molten salt pipeline 1, a cold molten salt storage tank 4 connected to the cold thermal storage molten salt pipeline 2, and a heat exchanger 5, as well as a first molten salt pump 301 and a second molten salt pump 302 for driving the molten salt flow. Among them, the dish-type dual-axis tracking concentrator 26 automatically adjusts its angle to absorb the most solar energy, and heats the thermal storage molten salt 27 in the cold thermal storage molten salt pipeline 2 by absorbing solar heat through the heat absorber 25. The purpose of using the hot molten salt storage tank 24 and the cold molten salt storage tank 4 is: during the day when solar energy resources are abundant, the heat storage molten salt 27 circulates in the hot molten salt storage tank 24, the heat exchanger 5, the cold molten salt storage tank 4 and the heat absorber 25, and stores part of the energy in the hot molten salt storage tank 24 while providing heat to the molten salt continuous electrolysis device 14. At night when solar energy resources are insufficient, the heat storage molten salt 27 flows from the hot molten salt storage tank 24 to the cold molten salt storage tank 4 and uses the stored solar energy to provide heat to the molten salt continuous electrolysis device 14.

[0081] The present invention does not have any special restrictions on the photovoltaic module. The photovoltaic module only needs to be able to absorb solar energy and store it, and the controller can control the entire system. Preferably, the photovoltaic module includes a solar charging module 23, a battery 22, and a controller 20. When in use, the battery 22 obtains solar energy provided by the solar charging module 23 to provide energy for electrolysis and the controller 20. The controller 20 can control the power of the electrolysis of the battery 22 and the movement of the cathode disk 28 according to the requirements of the flue gas load, and can control the flow rate of the electrolysis molten salt 42 in the electrolysis molten salt pipeline 6 and the heat storage molten salt 27 in the insulation jacket 10 according to the temperature measured by the thermocouple 40 to control the temperature in the molten salt continuous electrolysis device 14.

[0082] According to a best embodiment of the present invention, Figure 1 and Figure 2As shown, the solar thermal module includes several dish-type dual-axis tracking concentrators 26 and a matching heat absorber 25. The heat absorber 25 is connected to a casing branch consisting of a hot thermal storage molten salt pipeline 1 and a cold thermal storage molten salt pipeline 2. Each casing branch is led out from the casing main pipe. The hot thermal storage molten salt pipeline 1 in the casing main pipe is connected in sequence to the hot molten salt storage tank 24, the first molten salt pump 301, the heat exchanger 5, and the cold molten salt storage tank 4. The cold thermal storage molten salt pipeline 2 in the casing main pipe is connected in sequence to the second molten salt pump 302 and the cold molten salt storage tank 4. The photovoltaic module includes a solar charging module 23, a battery 22, and a controller 20. The molten salt continuous electrolysis device 14 includes an electrolysis mechanism, a grinding mechanism, an electrolysis molten salt circulation mechanism, a gas treatment mechanism, and a shell temperature control system. The electrolysis mechanism includes a cathode disk 28 and an anode disk 29 located within a crucible body 32, a brush 38 located within the cathode disk 28, and a cross-grinding fixture 36 for securing the cathode disk 28. Anode and cathode leads 34 and 35 extending from the battery 22 are connected to the anode disk 29 and the brush 38 within the cathode disk 28, respectively, through sleeves consisting of a cathode inner tube 31 and an anode outer tube 30 secured to the crucible lid 33. The grinding mechanism includes a controller 20 located outside the crucible body 32, an electric motor 17, and a cross-grinding fixture 36 connected to the cathode inner tube 31. The electric motor 17 is connected via a crankshaft 21 to a piston 19 located within a sliding channel in the crucible lid 33. The piston 19 is connected to a friction link 39, which is in turn connected to the cathode disk 28 via a fixing pin 41. The electrolytic molten salt circulation mechanism includes a cold electrolytic molten salt outlet 9 located in the middle of the sidewalls of the shell 12 and crucible 32, a hot electrolytic molten salt inlet 7 located at the lower sidewalls of the shell 12 and crucible 32, and an electrolytic molten salt pipeline 6 connecting the hot electrolytic molten salt inlet 7 and the cold electrolytic molten salt outlet 9. The electrolytic molten salt pipeline 6, which originates from the cold electrolytic molten salt outlet 9, sequentially connects to the carbon powder filtration and collection device 11, the third molten salt pump 303, the electrolytic molten salt storage tank, the heat exchanger 5, the electrolytic molten salt storage tank, the fourth molten salt pump 304, and the hot electrolytic molten salt inlet 7. The gas treatment mechanism includes a flue gas inlet pipeline 13 connected to the gas inlet, an exhaust gas outlet pipeline 18 connected to the gas outlet, a flue gas treatment device 15 near the gas inlet, and an exhaust gas treatment device 16 near the gas outlet. The shell temperature control system includes an insulation jacket 10, a controller 20, and a thermocouple 40.

[0083] According to a preferred embodiment of the present invention, the method for continuous photoelectrolysis of molten salt containing carbon dioxide and sulfur dioxide flue gas comprises the following steps:

[0084] (1) Turn on the solar thermal module. When the light source resources are sufficient, the dish-type dual-axis tracking concentrator 26 in the solar thermal module automatically tracks the sun, heating the heat storage molten salt 27 in the heat absorber 25. The heated molten salt enters the hot molten salt storage tank 24 through the hot heat storage molten salt pipeline 24. The molten salt in the hot molten salt storage tank 24 is controlled by the shell temperature control system composed of the thermocouple 40 and the controller 20. After being pressurized by the first molten salt pump 301, part of it flows to the insulation sleeve 10, and part of it flows to the heat exchanger 5 to exchange heat with the cold electrolytic molten salt 42. After the heat exchange is completed, the cold heat storage molten salt 27 flows to the cold heat storage molten salt storage tank 4, and then pressurized by the second molten salt pump 302 and returned to each heat absorber 25 through the cold heat storage molten salt pipeline 2 to complete the cycle. The excess heat is stored in the hot molten salt storage tank 24. When light resources are insufficient, the heat previously stored in hot molten salt storage tank 24 is utilized. The molten salt in hot molten salt storage tank 24 is controlled by the shell temperature control system composed of thermocouple 40 and controller 20. A portion of the molten salt is pressurized by first molten salt pump 301 and flows to insulation jacket 10, while another portion flows to heat exchanger 5 to exchange heat with cold electrolytic molten salt 42. After the heat exchange is completed, the cold thermal storage molten salt 27 flows to cold thermal storage molten salt storage tank 4, allowing the system to continue to operate normally even when solar energy is insufficient.

[0085] (2) Turn on the photovoltaic module. The solar charging module 23 in the photovoltaic module absorbs solar energy to generate electricity and stores it in the battery 22, which is used to supply the power required for the controller, motor, molten salt pump, and electrolysis.

[0086] (3) When electrolysis is required, the third molten salt pump 303 on the side of the first electrolysis molten salt storage tank 01 is turned on to press the liquid cold electrolysis molten salt into the heat exchanger 5. After heat exchange with the hot thermal storage molten salt 27, the liquid enters the second electrolysis molten salt storage tank 02. After being pressurized by the fourth molten salt pump 304, the liquid enters the crucible body 32 through the hot electrolysis molten salt inlet 7.

[0087] (4) Flue gas is introduced into the flue gas inlet pipe 13, and the dust and moisture in the flue gas are absorbed by the flue gas treatment device 15, and then introduced into the electrolytic molten salt 42.

[0088] (5) Turn on the motor 17 and rotate the crankshaft 21 to make the piston 19 slide up and down in the movable channel on the crucible cover, driving the friction connecting rod 39 to grind the cathode disc 28 on the one hand and rotate the cathode disc 28 in the cross grinding fixture 36 on the other hand. This not only stirs the electrolytic molten salt 42 to promote the reaction, but also ensures that the cross grinding fixture 36 grinds away the carbon generated on the other side of the cathode disc 28 during rotation, thereby promoting the continuous reaction.

[0089] (6) The ground carbon powder floats on the surface of the electrolytic molten salt 42, and after flowing out of the cold electrolytic molten salt outlet 9 through the electrolytic molten salt 42, it is removed in the carbon powder filtering and collecting device 11. At the same time, the exhaust gas is passed through the exhaust gas outlet pipe 18 to the exhaust gas treatment device 16, and is discharged into the atmosphere after treatment.

[0090] (7) When electrolysis needs to be suspended, the hot electrolysis molten salt inlet 7 is closed, and the electrolysis molten salt 42 in the pipeline is pressurized by the third molten salt pump 303 and the fourth molten salt pump 304 and stored in the first electrolysis molten salt storage tank 01 and the second electrolysis molten salt storage tank 02 for insulation. After the system stops operating, high-value-added carbon can be obtained by the carbon powder filtration and collection device 11.

[0091] In a preferred embodiment, the grinding mechanism of the present invention, including a cross-grinding fixture 36 and a friction connecting rod 39, effectively grinds the carbon attached to the cathode disc 28, improving the carbon removal and collection rate, while also driving the rotation of the cathode disc 28, thereby promoting the continuous and efficient occurrence of the electrolysis reaction. The provision of the electrolytic molten salt storage tank and the third and fourth molten salt pumps 303 and 304 allows the system to be started and shut down at any time, reducing the risk of molten salt condensation in the pipeline and avoiding the need for manual feeding during startup, thereby improving the degree of automation of the system operation. This also ensures that the system can operate continuously at night.

[0092] 2. In order to prove the creativity and technical value of the technical solution of the present invention, this section provides application examples of the claimed technical solution on specific products or related technologies.

[0093] Application Examples

[0094] This embodiment describes the configuration of the device proposed in the present invention to a thermal power plant in Xinjiang to treat and absorb CO2 in the tail gas and obtain high value-added C. It is known that the annual radiation amount at the location of the power plant is about 8000MJ / m 2 Y, molten salt temperature is 600℃, the rated output power of the power plant is 1000MW, the flue gas flow rate is 3190t / h, and the CO2 concentration is 13%.

[0095] In specific implementation, when in use, the flue gas is discharged into the flue gas inlet pipe, and the battery is used to power the cathode disc and the anode disc to generate carbon products and oxygen respectively. Then the controller controls the motor to drive the friction link to rotate the cathode disc, and the relative movement between the cathode disc, the friction link and the cross grinding fixture is used to grind the carbon products generated on the cathode disc into carbon powder. When the molten salt flows out of the molten salt continuous electrolysis device through the cold electrolysis molten salt outlet, the carbon powder floating on the surface of the molten salt is brought out of the electrolysis device, and the carbon powder is separated from the electrolysis molten salt by a carbon powder filtering and collecting device on the electrolysis molten salt pipeline.

[0096] Using solar thermal modules for heat and photovoltaic devices for power, a molten salt continuous electrolysis unit electrolyzes carbon dioxide and sulfur dioxide from flue gas. The cathode disk is driven to rotate, grinding the carbon products into carbon powder. The system continuously produces carbon powder. With an 80% CO2 removal rate, the system removes 493.6 tons of carbon dioxide per hour. Considering a 75% current efficiency for carbon powder production, and a 35% current efficiency to account for losses, approximately 47.1 tons of carbon powder can be produced per hour. Taking these losses into account, the energy required for electrolysis per kilogram of carbon is 95.96 kWh. Assuming a price of 1 yuan per kilowatt-hour, if solar energy were not used to electrolyze carbon dioxide, the cost of producing carbon powder per hour would likely be approximately 4.5 million yuan. If the recycling price of carbon powder is 5 yuan per kilogram at the market price, it can generate a profit of 230,000 yuan. Due to the heat storage function of the molten salt and the battery storage function of the photovoltaic module, the system can operate uninterruptedly throughout the year. The mass of carbon dioxide absorbed in 365 days a year is 4.32 million tons. Assuming that one acre of forest absorbs 67 kg of carbon dioxide every day, it is equivalent to the mass of carbon dioxide absorbed by planting 177 acres of forest. Electrolysis produces 410,000 tons of carbon powder a year, and the revenue from recycling the carbon powder produced by electrolysis is 2 billion yuan, saving 39.4 billion yuan in electricity costs for electrolysis of carbon dioxide.

[0097] 3. The embodiments of the present invention have achieved some positive results during the development or use process, and indeed have great advantages compared with the existing technology. The following content describes them in combination with data, charts, etc. of the experimental process.

[0098] experiment

[0099] The principle of high-temperature molten salt catalytic electrolysis of CO2 can be explained by the following expression, where M represents the metal cation of a component of the molten salt:

[0100] 2M2CO3=4M+2CO2(g)+O2(g)(1)

[0101] 3M2CO3=3M2O+2CO2(g)+C+O2(g)(2)

[0102] 4M2CO3=4M2O+2CO2(g)+2CO(g)+O2(g) (3)

[0103] CO2 is introduced into the molten salt, and the CO2 is converted into free O 2- and / or CO3 2- Capture and react to generate carbonate ions. The specific reaction is as follows:

[0104] O 2- +CO2(g)=CO3 2 (4)

[0105] CO3 2-+CO2(g)=C2O5 2- (5)

[0106] CO3 2- +nCO2(g)=C (n+1) O (2n+3) 2- (6)

[0107] Under the action of the electric field, the free O 2- and CO3 2- It approaches the anode and adsorbs on the anode, loses electrons and is oxidized to generate oxygen on the anode. The reaction is as follows:

[0108] O 2- -2e - =0.5O2(g)(7)

[0109] C (n+1) O (2n+3) 2- -2e - =(n+1)CO2(g)+0.5O2(g)(8)

[0110] Carbonate ions (CO3 2- and C (n+1) O (2n+3) 2- ) receives electrons and is reduced to form carbon and O 2- , the specific reactions are as follows:

[0111] CO3 2- +4e - =C+3O 2 (9)

[0112] C (n+1) O (2n+3) 2- +4e - =C+nCO2(g)+3O 2 (10)

[0113] In summary, the net reaction of the entire electrolysis process is:

[0114] CO2(g)=C+O2(g)(11)

[0115] A ternary mixed molten salt of Na2CO3, K2CO3 and Li2CO3 was used as the experimental thermal electrolysis molten salt. CO2 was introduced into the device and electrolysis was carried out at a constant charge of 500 mA·h at a cell voltage of 2.8V, 3.8V and 4.8V at molten salt temperatures of 450℃, 525℃ and 600℃ respectively.

[0116] In order to analyze the influence of electrolysis conditions on current efficiency and energy consumption, the present invention experimentally recorded the IT curves at different molten salt temperatures and different cell voltages at a capacity of 500 mAh. FIG10 shows the IT graph corresponding to different voltages of 500 mAh at 450°C, 525°C, and 600°C. Figure 10a The corresponding it curves under different cell pressures at a molten salt temperature of 450°C are shown below. When the cell pressure is 2.8V, the electrolysis current rises rapidly to 60mA in the first few minutes, then slowly decreases, and finally stabilizes at 30mA. When the cell pressure is 3.8V, the cell pressure gradually decreases with time, and finally stabilizes at 60mA. As the cell pressure increases, the corresponding current also gradually increases. When the molten salt temperature is 525°C, the corresponding it curve is as follows: Figure 10b As shown in the figure, the current is stable at 100mA at 2.8V. When the molten salt temperature is 600℃ and the cell voltage is 2.8V, the current is as follows: Figure 10c As shown, it is stable at 170mA. When the cell voltage is constant, as the molten salt temperature rises, the current of the electrolysis reaction also rises, and the speed of carbon deposition on the cathode surface becomes faster.

[0117] Figure 11 Electron graphs of the cathode product after cooling at 600°C at different cell voltages are shown. At a cell voltage of 2.8V, the carbon layer is relatively fluffy and contains a large amount of white salt. When the cell voltage is increased to 3.8V, the carbon layer becomes denser and contains less salt. When the cell voltage is increased to 4.8V, the carbon layer gradually becomes looser and contains more salt.

[0118] By comparing the mass of the treated carbon product with the mass of the carbon product calculated theoretically at constant charge, the current efficiency corresponding to the carbon product prepared at different molten salt temperatures and different cell pressures can be obtained, such as Figure 12 The current efficiency of carbon products prepared at different temperatures and cell pressures is shown in the figure. The current efficiency generally follows the trend of increasing with increasing electrolysis voltage. At 600℃ and 4.8V, the current efficiency decreases compared to 3.8V, which may be caused by side reactions such as CO or alkali metal reduction.

[0119] Figure 13 The energy consumption of carbon products prepared at different temperatures and different cell pressures is shown in the figure, which shows the electrolysis energy consumption of carbon prepared under different conditions. The energy consumption is calculated as E=U*Q / m, where E refers to energy consumption (unit: kW h kg -1 ), U refers to the cell voltage (unit: V), Q refers to the amount of electricity (unit: mAh), and m refers to the mass (g) of the cathode carbon product prepared under constant charge. The lowest energy consumption is 38.89kW h kg when the molten salt temperature is 450℃ and the cell voltage is 2.8V. -1The energy consumption is the highest at 58.62kW h kg-1 when the molten salt temperature is 600℃ and the cell voltage is 4.8V. The overall energy consumption increases with the increase of electrolysis voltage. Considering the current efficiency and energy consumption, the electrolysis of carbon dioxide at 600℃ and the cell voltage of 3.8V can be selected. Considering the actual comprehensive loss energy consumption, 95.96kWhkg-1 is taken. -1 At the current industrial electricity price of 1 yuan per kilowatt-hour, the cost of electrolyzing 1kg of carbon powder is around 50 yuan. The economic viability of electrolytically producing carbon powder is primarily determined by the added value of the carbon produced and the source of the electricity. The present invention's comprehensive use of light energy to electrolyze carbon dioxide can significantly reduce the electricity cost of electrolyzing carbon dioxide, reducing the cost of carbon dioxide emissions by approximately 10,000 yuan per ton, thereby achieving energy conservation and emission reduction.

[0120] Through the above scheme, the positive effects achieved by the present invention include: the photothermal module of the present invention adopts the method of dish-type solar concentrator plus molten salt storage tank, which occupies less space and is flexible in layout compared with other methods; the molten salt pipeline of the photothermal module of the present invention adopts the sleeve method of hot molten salt in the inner tube and cold molten salt between the outer tube and the inner tube, which effectively reduces the heat loss of the pipeline and improves the operation efficiency of the system; the photovoltaic module of the present invention uses photovoltaic power generation technology to provide the electric energy required for electrolysis, and the electric energy generated by photovoltaic power generation can also be used to maintain the operation of the controller and the molten salt pump, which is more environmentally friendly than the general direct use of electric energy to electrolyze CO2 and SO2. The molten salt continuous electrolysis device of the present invention includes an electrolysis mechanism, a grinding mechanism, an electrolysis molten salt circulation mechanism, a gas treatment mechanism, and a shell temperature control mechanism. The electrolysis mechanism powers the electrolysis process and provides a cathode for sulfur-containing carbon. The grinding mechanism grinds the sulfur-containing carbon attached to the cathode into powder to enable continuous operation. The electrolysis molten salt circulation mechanism provides hot molten salt for the electrolysis process to collect sulfur-containing carbon powder and allows for storage of the hot molten salt after operation. The gas treatment device pre-treats the input gas and treats the exhaust gas after electrolysis. The shell temperature control system uses the thermal storage molten salt of the solar thermal module to insulate the molten salt continuous circulation system. The molten salt continuous electrolysis device integrates multiple functions, enabling the structure to achieve continuous electrolysis of CO2 and SO2 and collect the high-value-added sulfur-containing carbon powder produced, achieving fully automated production compared to conventional equipment.

[0121] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A light-energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas, characterized in that: The light energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas comprises: The solar thermal module is used to heat the electrolytic molten salt to reach the required temperature for electrolysis of SO2 and CO2; Photovoltaic modules are used to convert solar energy into electrical energy to provide power for molten salt electrolysis and system operation; Continuous electrolysis device, adding a grinding mechanism to the equipment used for molten salt electrolysis of SO2 and CO2 to grind the generated carbon into carbon powder, and adding a carbon powder filtration and collection device to filter and collect the carbon powder floating on the hot molten salt to obtain high-value-added carbon; The continuous electrolysis device includes an electrolysis mechanism, a grinding mechanism, an electrolytic molten salt circulation mechanism, a gas treatment mechanism, and a shell temperature control system. Flue gas is discharged into a flue gas inlet pipe, and a battery is used to generate carbon products and oxygen on the cathode disc and anode disc, respectively. Then, a controller controls the motor to drive the friction link to rotate the cathode disc. The relative movement between the cathode disc, the friction link, and a cross grinding fixture is used to grind the carbon products generated on the cathode disc into carbon powder. When the molten salt flows out of the molten salt continuous electrolysis device through the cold electrolysis molten salt outlet, the carbon powder floating on the surface of the molten salt is carried out of the electrolysis device and separated from the electrolytic molten salt by a carbon powder filtering and collecting device on the electrolytic molten salt pipeline. The electrolysis mechanism supplies power to the molten salt continuous electrolysis device through a photoelectric module, detects the temperature of the electrolyzed molten salt through a thermocouple, and outputs a signal to the controller to control the discharge of the battery and control the load of the molten salt continuous electrolysis device. The battery supplies power to the cathode disc through the cathode wire in the cathode inner tube connected to the brush, and the battery supplies power to the anode disc through the anode wire in the anode outer tube. At the same time, there are sealing devices connected at the connection points, and the brushes supply power to the rotating cathode disc.

2. The light energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas according to claim 1, characterized in that: The grinding mechanism drives the rotation of the cathode disc through the movement of the friction link, and at the same time uses the friction surface of the friction link to grind the carbon generated on the side of the cathode disc close to the link into carbon powder; the cross grinding fixture is fixed by the cathode inner tube, and an insulating seal is filled between the cathode inner tube and the cross grinding fixture to prevent molten salt from entering the cathode inner tube and contacting the brush; the cross grinding fixture is fixed and driven by the friction link, so that the cathode disc is fixed during rotation and the carbon generated on the side of the cathode disc close to the cross grinding fixture is ground into carbon powder by the cross grinding fixture.

3. The light energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas according to claim 1, characterized in that: The hot electrolysis molten salt inlet of the electrolysis molten salt circulation mechanism is above the cold electrolysis molten salt inlet; The cold electrolytic molten salt inlet is at the molten salt liquid surface, allowing the carbon powder to flow out with the cold molten salt. The carbon powder is then separated from the molten salt in the carbon powder filtration and collection device on the electrolytic molten salt pipeline. After the carbon powder is separated from the cold molten salt, it flows through the heat exchanger and is reheated into hot molten salt. By setting up an electrolytic molten salt storage tank, the electrolytic molten salt can remain in the electrolytic molten salt storage tank when the system stops. Setting up two electrolytic molten salt storage tanks can separate the speeds at which the electrolytic molten salt flows through the continuous electrolysis device and the heat exchanger.

4. The light energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas according to claim 3, characterized in that: The molten salt can be stored in an electrolytic molten salt storage tank. By setting up two electrolytic molten salt storage tanks, the flow rates of the electrolytic molten salt in the pipelines of the heat exchanger and the molten salt continuous electrolysis device can be independent of each other and reach the maintenance of the electrolytic molten salt working temperature.

5. The light energy continuous electrolysis system for molten salt containing carbon dioxide and sulfur dioxide flue gas according to claim 1, characterized in that: The shell temperature control system consists of a shell wrapped around the outermost layer of the molten salt electrolysis device, a crucible body loaded with electrolytic molten salt, an insulation sleeve located between the shell and the crucible body, and a crucible cover located on the upper part of the molten salt continuous electrolysis device; the molten salt in the molten salt continuous electrolysis device is further heated by passing the heat storage molten salt into the insulation sleeve; the crucible body and the crucible cover are connected by bolts; the crucible body, the crucible cover and the shell are all made of insulation material; the crucible cover is also connected to a thermocouple, a piston and an anode outer tube.

6. A method for continuously electrolyzing molten salts from flue gas containing carbon dioxide and sulfur dioxide using the system for continuously electrolyzing molten salts from flue gas containing carbon dioxide and sulfur dioxide using light energy according to any one of claims 1 to 5, characterized in that: The method for continuously electrolyzing molten salt containing carbon dioxide and sulfur dioxide flue gas using light energy comprises: In step 1, the dish-type dual-axis tracking concentrator in the thermal module automatically tracks the sun, heating the thermal storage molten salt in the absorber. The heated molten salt enters the hot molten salt storage tank through the hot thermal storage molten salt pipeline. The molten salt in the hot molten salt storage tank is controlled by the shell temperature control system composed of thermocouples and controllers. After being pressurized by the molten salt pump, part of it flows to the insulation jacket, and part flows to the heat exchanger to exchange heat with the cold electrolysis molten salt. Step 2: The solar charging module in the photovoltaic module absorbs solar energy to generate electricity and stores it in the battery to supply the power required for the controller, motor, molten salt pump, and electrolysis; Step 3: During electrolysis, the molten salt pump on the side of the electrolysis molten salt storage tank is turned on to press the liquid cold electrolysis molten salt into the heat exchanger. After heat exchange with the hot thermal storage molten salt, it enters the electrolysis molten salt storage tank and is pressurized by the molten salt pump before entering the crucible body from the hot electrolysis molten salt outlet. Step 4: Flue gas is introduced into the flue gas inlet pipe, dust and moisture are absorbed by the flue gas treatment device, and then introduced into the electrolytic molten salt; Step 5: Turn on the motor and rotate the crankshaft to make the piston slide up and down in the movable channel on the crucible cover, driving the friction connecting rod to grind the cathode disc on the one hand and rotate the cathode disc in the cross grinding fixture on the other hand, thereby stirring the electrolytic molten salt and promoting the reaction. The cross grinding fixture grinds away the carbon generated on the other side of the cathode disc during rotation, promoting the continuous reaction. Step 6: The ground carbon powder floats on the surface of the electrolytic molten salt and is removed in a carbon powder filtration and collection device after the electrolytic molten salt flows out of the cold electrolytic molten salt outlet. At the same time, the exhaust gas is passed through the exhaust gas outlet pipe to the exhaust gas treatment device and discharged into the atmosphere after treatment. Step seven: When electrolysis is suspended, the hot electrolytic molten salt inlet is closed, and the electrolytic molten salt in the pipeline is pressurized by the molten salt pump and stored in two electrolytic molten salt storage tanks for insulation; after the system stops running, high-value-added carbon is obtained by the carbon powder filtering and collecting device.

7. The method for continuous electrolysis of molten salt containing carbon dioxide and sulfur dioxide flue gas using light energy according to claim 6, characterized in that: After the heat exchange in step 1 is completed, the cold thermal storage molten salt flows to the cold thermal storage molten salt storage tank.

8. An industrial carbon dioxide and sulfur dioxide flue gas removal device, characterized in that: The industrial carbon dioxide and sulfur dioxide flue gas removal device is equipped with the light energy continuous electrolysis of carbon dioxide and sulfur dioxide flue gas molten salt system according to any one of claims 1 to 5.

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