A solid carbon preparation system and method based on molten salt battery capture

Abstract

The application provides a solid carbon preparation system and method based on molten salt battery trapping, relates to the field of carbon dioxide trapping, and aims to solve the problems of large energy consumption caused by cooling and carbon extraction, and heating by grid power in the process of extracting solid carbon by molten salt electrochemical conversion. The molten salt is heated by a solar heat collector and then introduced into a molten salt battery, so that the molten salt in the molten salt battery is maintained in a suitable high-temperature liquid state. The molten salt is continuously pumped into the molten salt battery by a molten salt pump, reacts with the carbon dioxide supplied by an upstream carbon dioxide trapping unit, and the carbon-containing molten salt discharged after the reaction enters a filtering assembly and is subjected to in-situ solid-liquid separation under the condition of maintaining a high-temperature liquid state. The separated solid carbon enters a collector, the steps of molten salt cooling and solidification and water washing and acid washing in the intermittent process are effectively avoided, the loss of electrolyte salt and the system heat loss caused by cold and hot alternation are reduced, and the energy consumption is reduced by using renewable solar energy.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture, and more specifically to a solid carbon preparation system and method based on molten salt battery capture. Background Technology

[0002] Carbon dioxide capture technologies mostly rely on physicochemical processes such as solvent absorption, solid adsorption, or membrane separation. Currently, carbon resources can also be realized through molten salt electrochemical conversion technology, which can directly reduce carbon dioxide into high-value-added solid carbon materials such as graphitized carbon or carbon nanotubes under relatively mild conditions.

[0003] In molten salt electrochemical capture, in order to extract solid carbon deposited on the electrode surface, it is usually necessary to interrupt the reaction and wait for the entire molten salt system to cool and solidify. Subsequently, the salt coating the carbon product is dissolved and removed by destructive methods such as water washing and acid washing. The electrolyte salt is lost and cannot be recovered. Molten salt relies on grid power for internal heating to maintain high temperature. When extracting solid carbon after cooling, the huge amount of heat energy accumulated in the system is dissipated in the alternation of hot and cold. It is difficult to resolve the contradiction between the high energy consumption of electric heating after cooling of high-temperature molten salt and the need for destructive separation of the product after cooling. Summary of the Invention

[0004] In view of this, the present invention provides a solid carbon preparation system and method based on molten salt battery capture, which reduces the loss of electrolyte salt and the system heat loss caused by alternating hot and cold, and alleviates the drawbacks of relying on high-energy-consuming grid electricity for heating by utilizing renewable solar energy.

[0005] The first objective of this invention is to provide a solid carbon preparation system based on molten salt battery trapping, employing the following scheme: include: The carbon dioxide capture unit includes an absorption tower, a carbonate reactor, and a calcining furnace connected in sequence. After the absorption tower absorbs carbon dioxide, the solution generates calcium carbonate in the carbonate reactor and is fed into the calcining furnace to output carbon dioxide gas. The solid carbon preparation unit includes a molten salt cell, a molten salt storage tank, and a solar collector for heating the molten salt storage tank. The molten salt cell receives carbon dioxide gas from the calcining furnace and liquid molten salt pumped into the molten salt storage tank by a molten salt pump. The diversion and recovery unit includes a filter assembly and a collector. The filter assembly is connected to the discharge port of the molten salt battery and is used to separate the liquid molten salt and the solid carbon generated by the reaction. The separated liquid molten salt is returned to the molten salt storage tank through a return pipe, and the separated solid carbon enters the collector.

[0006] Furthermore, the absorption tower is equipped with a spraying device and a liquid redistribution device. The spraying device is suspended at the top of the absorption tower, and multiple liquid redistribution devices are distributed vertically along the absorption tower. The carbonate reactor is equipped with a filter to separate calcium carbonate and to return the remaining solution after separation to the absorption tower for recycling as absorbent liquid.

[0007] Furthermore, the carbon dioxide capture unit also includes a calcium oxide collection chamber. The solid inlet of the calcium oxide collection chamber is connected to the solid outlet of the calcining furnace to receive the calcium oxide produced by calcination. The outlet of the calcium oxide collection chamber is connected to the carbonate reactor through a water injection pipeline to convert the calcium oxide into a calcium hydroxide solid-liquid mixture and circulate it to the carbonate reactor.

[0008] Furthermore, a pneumatic feeder is provided at the connection pipe between the carbonate reactor and the calcining furnace to quantitatively and continuously deliver calcium carbonate into the calcining furnace.

[0009] Furthermore, the filtration assembly includes a heat-resistant filter plate, which is capable of in-situ separation of liquid molten salt and solid carbon without cooling the molten salt.

[0010] Furthermore, the liquid molten salt is a ternary eutectic molten salt, and the solar collector is a trough-type solar collector system. Its heat collection surface is in contact with the molten salt storage tank, and it can adjust the heating power to maintain the temperature of the liquid molten salt within the set directional reaction range.

[0011] Furthermore, the cathode material of the molten salt battery is matched with the directional reaction zone to utilize the corresponding temperature and the catalytic effect of the material surface to directionally generate solid carbon of a specific crystal form.

[0012] Furthermore, when the set directional reaction range is 700-750℃, the cathode material of the molten salt battery is a copper plate or a nickel plate to directionally generate carbon nanotubes. When the set directional reaction range is 520-550℃, the cathode material of the molten salt battery is a graphite plate to directionally generate graphitized carbon.

[0013] A second objective of this invention is to provide a method for preparing a solid carbon preparation system based on molten salt battery trapping, utilizing the solid carbon preparation system based on molten salt battery trapping as described in the first objective, comprising: The solution absorbs carbon dioxide from the air in the absorption tower. After absorbing carbon dioxide, the solution is converted into calcium carbonate solid in the carbonate reactor. The calcium carbonate solid enters the calcination furnace and is calcined at high temperature to separate high-purity carbon dioxide gas and calcium oxide. The solar collector is used to independently heat the molten salt storage tank, keeping the molten salt in the tank in a liquid state and reaching the set reaction temperature. Then, the molten salt is continuously pumped into the molten salt battery via the molten salt pump. High-purity carbon dioxide gas is introduced into a molten salt battery, where an electrochemical reduction reaction occurs in a liquid molten salt environment to generate a solid carbon mixture. Liquid molten salt containing solid carbon is discharged from the discharge port to the filter assembly, where solid-liquid separation is carried out directly while maintaining the high temperature of the liquid. The separated high-temperature liquid molten salt is circulated back to the molten salt storage tank through the return pipe, and the retained solid carbon enters the collector.

[0014] Furthermore, in the electrochemical reduction reaction, solid carbon with a specific crystal form is generated by controlling the temperature of the molten salt and the cathode material of the molten salt battery.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: To address the problem of high energy consumption caused by cooling during carbon extraction and heating with grid electricity during the electrochemical conversion of molten salt to solid carbon, this invention utilizes a solar collector to heat molten salt before introducing it into a molten salt cell. This maintains the molten salt in a suitable high-temperature liquid state within the cell, which is then continuously pumped into the cell by a molten salt pump. The molten salt reacts with carbon dioxide supplied by an upstream carbon dioxide capture unit. The carbon-containing molten salt discharged after the reaction enters a filtration component, where in-situ solid-liquid separation is performed while maintaining a high-temperature liquid state. The separated solid carbon enters a collector, while the liquid molten salt, carrying a large amount of residual heat, is returned to the molten salt storage tank through a return pipe for continued recycling. This effectively avoids the steps of molten salt cooling and solidification, as well as water washing and acid washing, found in intermittent processes. It also reduces electrolyte salt loss and system heat loss caused by alternating heating and cooling, and utilizes renewable solar energy to alleviate the drawbacks of relying on high-energy-consuming grid electricity for heating. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1 This is a schematic diagram of the solid carbon preparation system based on molten salt battery trapping in Embodiments 1 and 2 of the present invention.

[0018] Figure 2 This is a schematic diagram of the absorption tower structure in Embodiments 1 and 2 of the present invention.

[0019] Figure 3 This is a schematic diagram of the molten salt battery in Embodiments 1 and 2 of the present invention.

[0020] The components are as follows: 1. Silo; 2. Absorption tower; 3. Filter; 4. Carbonate reactor; 5. Pneumatic feeder; 6. Feeder; 7. Calcining furnace; 8. Calcium oxide collection silo; 9. Molten salt battery; 10. Molten salt pump; 11. Molten salt storage tank; 12. Filter assembly; 13. Collector; 14. Solar collector; 15. Spraying device; 16. Liquid redistribution device; 17. Reaction chamber; 18. Cathode; 19. Anode. Detailed Implementation

[0021] Example 1 In a typical embodiment of the present invention, such as Figure 1 - Figure 3 As shown, a solid carbon preparation system based on molten salt battery trapping is presented.

[0022] In the traditional method of solid carbon extraction during molten salt electrochemical capture, the process is quite cumbersome and the energy consumption is high due to alternating hot and cold conditions. In this regard, this embodiment provides a solid carbon preparation system based on molten salt battery 9 capture, which can make full use of solar energy, reduce pollutants and carbon emissions, and perform in-situ solid-liquid separation under the condition of maintaining high temperature liquid state, thereby reducing the loss of electrolyte salt and the system heat loss caused by alternating hot and cold conditions.

[0023] like Figure 1 As shown, the solid carbon preparation system based on molten salt battery 9 includes a carbon dioxide capture unit, a solid carbon preparation unit, and a diversion and recovery unit.

[0024] The carbon dioxide capture unit includes an absorption tower 2, a carbonate reactor 4, and a calcining furnace 7 connected in sequence. After the absorption tower 2 absorbs carbon dioxide, the solution generates calcium carbonate in the carbonate reactor 4. The generated calcium carbonate is then fed into the calcining furnace 7 for calcination. After the calcium carbonate is calcined and decomposed at high temperature, carbon dioxide is generated and carbon dioxide gas is output.

[0025] The solid carbon preparation unit includes a molten salt battery 9, a molten salt storage tank 11, and a solar collector 14 for heating the molten salt storage tank 11. The molten salt battery 9 receives carbon dioxide gas from the calcining furnace 7 and liquid molten salt pumped into the molten salt storage tank 11 by the molten salt pump 10. The solar collector 14 can heat the molten salt in the molten salt storage tank 11, so that the molten salt is in a good flow state and at the required reaction temperature.

[0026] The diversion and recovery unit includes a filter assembly 12 and a collector 13. The filter assembly 12 is connected to the discharge port of the molten salt battery 9. Molten salt carrying solid carbon is input into the filter assembly 12 to separate the liquid molten salt and the solid carbon generated by the reaction. The separated liquid molten salt is returned to the molten salt storage tank 11 through the return pipe and readjusted to the required reaction temperature. The separated solid carbon enters the collector 13.

[0027] like Figure 1 and Figure 2 As shown, absorption tower 2 is a packed tower, and the solution is potassium hydroxide solution. Absorption tower 2 is equipped with two inlets and one outlet. Pretreated air is introduced through inlet A, and recovered potassium hydroxide solution and replenished potassium hydroxide solution are introduced through inlet B. The outlet is connected to carbonate reactor 4 by a conveying pipeline. It is understood that in other optional embodiments, the solution can also be sodium hydroxide solution, etc.

[0028] In the carbonate reactor 4, calcium carbonate filtered through filter 3 is introduced into the solid outlet, while the filtered potassium hydroxide solution is supplied to the liquid outlet. The recovered potassium hydroxide is then returned to the absorption tower 2. The solid outlet is connected to a feeder to collect the calcium carbonate produced in the reaction. The feeder is a pneumatic feeder 5, whose outlet is connected to the calcining furnace 7, feeding in the generated calcium carbonate solid. The pneumatic feeder 5 ensures the quantitative delivery of the calcium carbonate solid, guaranteeing a stable and sufficient production of carbon dioxide in the calcining furnace 7.

[0029] The calcining furnace 7 is a rotary kiln type calcining furnace 7. The two discharge ports of the rotary kiln type calcining furnace 7 are connected to the calcium oxide collection chamber 8 and the molten salt battery 9 carrying high-temperature molten salt respectively through conveying pipes. The gas discharge port conveys carbon dioxide gas and enters the molten salt battery 9 of the solid carbon preparation unit through the pipe. The solid discharge port sends the calcium oxide solid generated by calcination to the upper layer of the calcium oxide collection chamber 8. After cooling, it is sent to the lower layer of the calcium oxide collection chamber 8. The calcium oxide collection chamber 8 recovers the calcium oxide generated by calcination. The lower layer of the calcium oxide collection chamber 8 is equipped with a water inlet. The water inlet introduces water into the lower layer of the calcium oxide collection chamber 8 to generate a calcium hydroxide solid-liquid mixture, which is then returned to the carbonate reactor 4.

[0030] The solid carbon preparation unit includes a high-temperature molten salt battery 9, a molten salt pump 10, a molten salt storage tank 11, and a solar collector 14. A calcining furnace 7 is connected to the high-temperature molten salt battery 9 via a gas pipeline. The molten salt pump 10 connects the molten salt battery 9 and the molten salt storage tank 11, transporting the heated molten salt. The solar collector 14 is installed on the molten salt storage tank 11 to provide heat. The filter assembly 12 of the diversion and recovery unit can withstand the high temperature of the molten salt and is located near the outlet of the molten salt battery 9.

[0031] At the same time, such as Figure 2As shown, a spray device 15 is installed inside the absorption tower 2. The spray device 15 is suspended at the top inside the absorption tower 2 and can spray liquid into the reaction chamber 17 inside the absorption tower 2. The spray device 15 can adopt a structure such as a spray pipe network or a perforated plate. The spray device 15 is made of a material that can withstand the corrosiveness of the solution. When pipeline transportation is used, the strength of the pipeline must be ensured to withstand the water pressure during spraying. The diameter of the pipeline and the pumping speed must meet the solution demand of the absorption tower 2 during operation. The spray device 15 can spray water mist, water curtain, or water curtain. The distribution density and aperture of the spray holes can also be configured according to requirements to control the distribution range of the solution and adjust the contact area between the solution and the air.

[0032] The absorption tower 2 is also equipped with a liquid redistribution device 16, and multiple devices are distributed vertically along the absorption tower 2. The liquid redistribution device 16 can adopt a structure such as a water distributor or a perforated plate to output the solution in different areas, thereby increasing the contact area and contact time between air and potassium hydroxide and improving the absorption rate of carbon dioxide.

[0033] Absorption tower 2 is a packed tower that directly uses air as raw material to absorb and efficiently utilize carbon dioxide in the air, which can effectively mitigate the greenhouse effect caused by carbon dioxide.

[0034] like Figure 1 As shown, the fuel required for the operation of the calcining furnace 7 enters the calcining furnace 7 through the feeder 6. The calcium oxide collection bin 8 releases heat during the process of generating calcium hydroxide solution after water is introduced. This heat can be collected through heat pipes, heat exchangers, etc., and then transported to the connection position between the solid discharge port of the carbonate reactor 4 and the pneumatic feeder 5 to preheat the filtered calcium carbonate solid, remove some of the water attached to the calcium carbonate, reduce its water content, and thus reduce the energy consumption in the calcining furnace 7.

[0035] In this embodiment, the filter assembly 12 includes a heat-resistant filter plate, which can separate liquid molten salt and solid carbon in situ without cooling the molten salt. The heat-resistant filter plate can be made of silicon carbide ceramic material, which can withstand the high temperature of the molten salt, achieving the separation of liquid molten salt and solid carbon. The solid carbon is blocked on one side of the heat-resistant filter plate, while the liquid molten salt can pass through the heat-resistant filter plate and enter the subsequent molten salt storage tank 11. The heat-resistant filter plate can adopt a perforated plate structure or a filter screen structure, where the pore size of the corresponding filter holes or mesh is smaller than the particle size of the solid carbon entrained in the liquid molten salt. Furthermore, as the solid carbon accumulates, the flow resistance to the liquid molten salt also increases. After the solid carbon accumulates to a certain amount, the solid carbon attached to and blocked on the heat-resistant filter plate is collected, and the collected coarse product enters the collector 13. The collector 13 can be a storage container to store the solid carbon filtered out by the filter assembly 12. Subsequently, high-purity solid carbon material can be obtained through washing, drying, and other processes.

[0036] like Figure 1 As shown, the liquid molten salt is a lithium carbonate-sodium carbonate-potassium carbonate ternary eutectic molten salt. Cathode 18 is connected to the negative terminal of the power supply, and anode 19 is connected to the positive terminal. The electrolytic cell of the molten salt battery 9 is filled with lithium carbonate-sodium carbonate-potassium carbonate ternary eutectic molten salt. Carbon dioxide is introduced into the electrolytic cell and first reacts... Anode 19 occurs Cathode 18 occurs Carbon is deposited on the cathode 18 of the battery.

[0037] The solar collector 14 is a trough-type solar thermal system. Its collecting surface is in contact with the molten salt storage tank 11 and installed on the outside of the molten salt storage tank 11. It heats the molten salt inside the molten salt storage tank 11 and can adjust the heating power to maintain the temperature of the liquid molten salt within a set directional reaction range. In addition, the molten salt storage tank 11 is also connected to a molten salt pump 10 through a pipeline to continuously transport the molten salt in the molten salt storage tank 11 to the molten salt battery 9. Using the trough-type solar collector 14 can make full use of solar energy, reduce pollutants and carbon emissions, and is relatively easy to operate. At the same time, it can adjust the heating power, control the temperature range, and ensure the directional generation of solid carbon products.

[0038] The cathode 18 material of the molten salt battery 9 is matched with the directional reaction zone to directionally generate solid carbon of a specific crystal form by utilizing the corresponding temperature and the catalytic effect of the material surface.

[0039] If the temperature is below 500℃, the viscosity of the molten salt will increase, the ion migration efficiency will decrease, the carbon dioxide reduction rate will be greatly reduced, and granular or honeycomb carbon materials will be easily formed. If the temperature is above 750℃, the molten salt will easily volatilize and cause loss. At the same time, the carbon atom growth rate is too fast, which will destroy the tubular structure of carbon nanotubes and form coarse-grained graphitized carbon or graphite sheet stacks. It will also aggravate electrode corrosion. Metal impurities dissolved in the molten salt may interfere with the purity and morphology of the carbon products.

[0040] In this embodiment, if the goal is to generate carbon graphitization, such as Figure 3 As shown, the anode 19 of the molten salt battery 9 is made of inert graphite material, and the cathode 18 is made of high-purity graphite plate without metal catalyst loading. The set directional reaction range is 520-550℃. After carbon dioxide gas enters the molten salt battery 9, an electrolytic reaction occurs in the cathode 18 area, and graphitized carbon is deposited near the cathode 18. The high-temperature molten salt battery 9 is connected to the filter component 12 made of silicon carbide ceramic material. The graphitized carbon solid generated after the reaction and the molten salt mixture enter the filter component 12 to complete solid-liquid separation. The separated molten salt is transported back to the molten salt storage tank 11 through the pipeline, and after reheating, it enters the reaction again.

[0041] The filter assembly 12 transports the separated graphitized carbon crude product to the solid carbon collector 13. The solid carbon collector 13 completes the collection of the graphitized carbon crude product. After subsequent washing, drying and refining treatment, the crude product is used to obtain the graphitized carbon finished product, thus completing the carbon dioxide capture and solid carbon preparation process of the entire system.

[0042] When the target product is carbon nanotubes, the directional reaction range is set at 700-750℃. The cathode 18 of the molten salt battery 9 uses a copper or nickel plate to directionally generate carbon nanotubes. The cathode 18 material is selected from high-purity copper or nickel plates, whose surface has a catalytic effect on the growth of carbon nanotubes. The carbon atoms generated by the molten salt battery 9 grow orderly on the surface of the cathode 18 to form carbon nanotubes. The battery operating temperature is controlled between 700-750℃, which is conducive to the formation of carbon nanotubes and avoids the formation of honeycomb-like carbon or amorphous carbon at excessively low temperatures.

[0043] Similarly, the molten salt mixture containing carbon nanotubes is discharged from the high-temperature molten salt battery 9 and passed into a filter assembly 12 made of silicon carbide ceramic filter plate, where solid carbon nanotubes and liquid molten salt are separated at high temperature. The crude carbon nanotubes obtained by filtration are sent to a solid carbon collector 13, and after washing, drying and other processes, high-purity carbon nanotube finished products can be obtained.

[0044] Example 2 In another typical embodiment of the present invention, such as Figure 1 - Figure 3 As shown, a method for preparing solid carbon based on a molten salt battery 9 trapping system is presented. The method utilizes the solid carbon preparation system based on a molten salt battery 9 trapping system as described in Example 1, including: The solution absorbs carbon dioxide from the air in the absorption tower 2. After absorbing carbon dioxide, the solution is converted into calcium carbonate solid in the carbonate reactor 4. The calcium carbonate solid enters the calcining furnace 7 and is calcined at high temperature to separate high-purity carbon dioxide gas and calcium oxide. The solar collector 14 is used to independently heat the molten salt storage tank 11, keeping the molten salt in the tank in a liquid state and reaching the set reaction temperature. Then, the molten salt is continuously pumped into the molten salt battery 9 by the molten salt pump 10. High-purity carbon dioxide gas is introduced into molten salt battery 9, where an electrochemical reduction reaction occurs in the liquid molten salt environment to generate a solid carbon mixture. Liquid molten salt containing solid carbon is discharged from the discharge port to the filter assembly 12, where solid-liquid separation is carried out directly under the condition of maintaining the high temperature of the liquid. The separated high-temperature liquid molten salt is circulated to the molten salt storage tank 11 through the return pipe, and the retained solid carbon enters the collector 13.

[0045] In the electrochemical reduction reaction, solid carbon of a specific crystal form is generated by controlling the temperature of the molten salt and the cathode 18 material of the molten salt battery 9. If the goal is to generate graphitized carbon, the anode 19 of the molten salt battery 9 is made of inert graphite material, and the cathode 18 is made of high-purity graphite plate without metal catalyst support. The set directional reaction range is 520-550℃. After carbon dioxide gas enters the molten salt battery 9, an electrolytic reaction occurs in the cathode 18 region, and graphitized carbon is deposited near the cathode 18.

[0046] When the target product is carbon nanotubes, the directional reaction range is set at 700-750℃. The cathode 18 of the molten salt battery 9 uses a copper or nickel plate to directionally generate carbon nanotubes. The cathode 18 material is selected from high-purity copper or nickel plates, whose surface has a catalytic effect on the growth of carbon nanotubes. The carbon atoms generated by the molten salt battery 9 grow in an orderly manner on the surface of the cathode 18 to form carbon nanotubes.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid carbon preparation system based on molten salt battery trapping, characterized in that, include: The carbon dioxide capture unit includes an absorption tower, a carbonate reactor, and a calcining furnace connected in sequence. After the absorption tower absorbs carbon dioxide, the solution generates calcium carbonate in the carbonate reactor and is fed into the calcining furnace to output carbon dioxide gas. The solid carbon preparation unit includes a molten salt cell, a molten salt storage tank, and a solar collector for heating the molten salt storage tank. The molten salt cell receives carbon dioxide gas from the calcining furnace and liquid molten salt pumped into the molten salt storage tank by a molten salt pump. The diversion and recovery unit includes a filter assembly and a collector. The filter assembly is connected to the discharge port of the molten salt battery and is used to separate the liquid molten salt and the solid carbon generated by the reaction. The separated liquid molten salt is returned to the molten salt storage tank through a return pipe, and the separated solid carbon enters the collector.

2. The solid carbon preparation system based on molten salt battery trapping as described in claim 1, characterized in that, The absorption tower is equipped with a spray device and a liquid redistribution device. The spray device is suspended at the top of the absorption tower. Multiple liquid redistribution devices are distributed vertically along the absorption tower. The carbonate reactor is equipped with a filter to separate calcium carbonate and can return the remaining solution after separation to the absorption tower for recycling as absorbent.

3. The solid carbon preparation system based on molten salt battery trapping as described in claim 1, characterized in that, The carbon dioxide capture unit also includes a calcium oxide collection chamber. The solid inlet of the calcium oxide collection chamber is connected to the solid outlet of the calcining furnace to receive the calcium oxide produced by calcination. The outlet of the calcium oxide collection chamber is connected to the carbonate reactor through a water injection pipeline to convert the calcium oxide into a calcium hydroxide solid-liquid mixture and circulate it to the carbonate reactor.

4. The solid carbon preparation system based on molten salt battery trapping as described in claim 1, characterized in that, A pneumatic feeder is installed at the connection pipe between the carbonate reactor and the calcining furnace to quantitatively and continuously deliver calcium carbonate into the calcining furnace.

5. The solid carbon preparation system based on molten salt battery trapping as described in claim 1, characterized in that, The filtration assembly includes a heat-resistant filter plate, which can separate liquid molten salt and solid carbon in situ without cooling the molten salt.

6. The solid carbon preparation system based on molten salt battery trapping as described in claim 1, characterized in that, The liquid molten salt is a ternary eutectic molten salt, and the solar collector is a trough-type solar collector system. Its heat collection surface is in contact with the molten salt storage tank, and it can adjust the heating power to keep the temperature of the liquid molten salt within the set directional reaction range.

7. The solid carbon preparation system based on molten salt battery trapping as described in claim 6, characterized in that, The cathode material of the molten salt battery is matched with the directional reaction zone to utilize the corresponding temperature and the catalytic effect of the material surface to directionally generate solid carbon of a specific crystal form.

8. The solid carbon preparation system based on molten salt battery trapping as described in claim 7, characterized in that, When the set directional reaction range is 700-750℃, copper or nickel plates are used as the cathode material of the molten salt battery to directionally generate carbon nanotubes. When the set directional reaction range is 520-550℃, the cathode material of the molten salt battery is a graphite plate to directionally generate graphitized carbon.

9. A method for preparing a solid carbon preparation system based on molten salt battery trapping, utilizing the solid carbon preparation system based on molten salt battery trapping as described in any one of claims 1-8, characterized in that, include: The solution absorbs carbon dioxide from the air in the absorption tower. After absorbing carbon dioxide, the solution is converted into calcium carbonate solid in the carbonate reactor. The calcium carbonate solid enters the calcination furnace and is calcined at high temperature to separate high-purity carbon dioxide gas and calcium oxide. The solar collector is used to independently heat the molten salt storage tank, keeping the molten salt in the tank in a liquid state and reaching the set reaction temperature. Then, the molten salt is continuously pumped into the molten salt battery via the molten salt pump. High-purity carbon dioxide gas is introduced into a molten salt battery, where an electrochemical reduction reaction occurs in a liquid molten salt environment to generate a solid carbon mixture. Liquid molten salt containing solid carbon is discharged from the discharge port to the filter assembly, where solid-liquid separation is carried out directly while maintaining the high temperature of the liquid. The separated high-temperature liquid molten salt is circulated back to the molten salt storage tank through the return pipe, and the retained solid carbon enters the collector.

10. The preparation method of the solid carbon preparation system based on molten salt battery trapping as described in claim 9, characterized in that, In the electrochemical reduction reaction, solid carbon with a specific crystal form is generated by controlling the temperature of the molten salt and the cathode material of the molten salt battery.

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