Carbon dioxide purification device, carbonate conversion equipment and control method

Abstract

The invention relates to the technical field of carbon dioxide purification, and provides a carbon dioxide purification device, carbonate conversion equipment and a control method.The carbon dioxide purification device comprises a refrigerator and a cold pipe, the refrigerator is provided with a cold head, and the cold head is used for releasing cold energy; part of the cooling pipe is spirally arranged on the periphery of the cooling head in a sleeving mode, the cooling pipe is provided with a gas inlet and a gas outlet, raw material gas containing carbon dioxide enters from the gas inlet, the gas outlet is used for exhausting, and the refrigerating machine can adjust the temperature in the cooling pipe according to condensation points of all gas in the raw material gas. According to the carbon dioxide purification device, the carbonate conversion equipment and the control method, the purity of carbon dioxide can be improved.

Description

Technical Field

[0001] This application relates to the field of carbon dioxide purification technology, and in particular to a carbon dioxide purification apparatus, a carbonate conversion device, and a control method. Background Technology

[0002] In establishing a traceability system for the mass values ​​of carbon dioxide stable isotope gas standards, it is necessary to use carbonate conversion equipment to prepare carbon dioxide gas with accurate carbon isotope δ values. Mass traceability requires high measurement accuracy and necessitates obtaining carbon dioxide gas of high purity. Multi-component impurities in the carbon dioxide gas need to be removed at low temperatures. Therefore, a common practice is to place the cold trap of the carbonate conversion equipment within a self-made liquid nitrogen container, providing a low-temperature environment and removing impurities by immersing the cold trap in liquid nitrogen.

[0003] However, during the impurity removal process, factors such as liquid nitrogen evaporation and gas flow heat transfer can cause changes in the liquid nitrogen level. These changes in level can lead to temperature variations in the cold trap, resulting in a deterioration in the impurity removal effect. This is usually maintained by manually monitoring and replenishing the liquid level, which is cumbersome and difficult to programmatically control. Furthermore, different cryogenic conditions need to be selected to remove impurities with different condensation points from carbon dioxide. When the temperature is limited to the temperature of liquid nitrogen, it is not possible to accurately remove impurities with different condensation points from carbon dioxide, affecting the impurity removal effect and consequently the measurement accuracy in the traceability process. Summary of the Invention

[0004] In view of this, embodiments of this application aim to provide a carbon dioxide purification apparatus, a carbonate conversion device, and a control method that can improve the purity of carbon dioxide.

[0005] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0006] One embodiment of this application discloses a carbon dioxide purification apparatus, comprising:

[0007] A refrigeration unit having a cold head for releasing cold energy;

[0008] A cooling pipe, part of which is spirally sleeved around the outer periphery of the cold head, has an inlet and an outlet. Raw material gas containing carbon dioxide enters through the inlet, and the outlet is used for exhaust. The refrigeration unit can adjust the temperature inside the cooling pipe according to the condensation point of each gas in the raw material gas.

[0009] In one embodiment, the refrigerator is a pulse tube refrigerator; and / or, the cold head is made of oxygen-free copper.

[0010] In one embodiment, the purification device includes a housing that forms a refrigeration chamber, and the cold head is disposed in the refrigeration chamber.

[0011] In one embodiment, the cooling pipe includes a coil, an inlet pipe, and an outlet pipe. The coil is spirally wound around the cooling head. The inlet pipe and the outlet pipe are respectively connected to one end of the coil and extend out of the housing. The inlet pipe has the inlet port, and the outlet pipe has the outlet port. The purification device includes a first switching valve and a second switching valve. The first switching valve is disposed in the inlet pipe, and the second switching valve is disposed in the outlet pipe.

[0012] In one embodiment, the purification device includes a housing and a vacuum pump. The housing, the inlet pipe, and the outlet pipe are all disposed inside the housing. The vacuum pump is used to adjust the vacuum level inside the housing.

[0013] In one embodiment, the outer casing is made of stainless steel; and / or, the purification device includes a venting valve disposed on the outer casing.

[0014] In one embodiment, the purification apparatus includes a chiller connected to the refrigeration unit via a pipe.

[0015] Another aspect of this application discloses a carbonate conversion device, including a collection system, a reaction system, and a carbon dioxide purification device as described in any of the above embodiments, wherein the inlet is connected to the reaction system and the outlet is connected to the collection system.

[0016] In another aspect, this application discloses a control method applied to the purification apparatus in any of the above embodiments, the control method comprising:

[0017] The temperature inside the cold pipe is adjusted by the refrigeration unit to purify the carbon dioxide in the cold pipe.

[0018] In one embodiment, the control method includes:

[0019] The temperature inside the cooling pipe is adjusted to a preset temperature so that the mixed gas containing carbon dioxide in the raw material gas above the preset temperature condenses, and the uncondensed impurity gas is extracted and separated.

[0020] Based on the condensation points of the impurity gases in the mixed gas and the condensation point of the carbon dioxide, the temperature inside the cold pipe is gradually increased to separate the impurity gases and the carbon dioxide from the mixed gas.

[0021] This application discloses a carbon dioxide purification device, a carbonate conversion device, and a control method. By employing a refrigeration unit for temperature regulation, compared to the prior art of immersion in a liquid nitrogen container, the temperature inside the cold pipe can be flexibly adjusted to target gases with different condensation points in the raw material gas. This results in better temperature control accuracy and purification effect. By spirally winding the cold pipe around the outer circumference of the cold head, on the one hand, the spiral structure can induce gas rotational flow, thus significantly enhancing the turbulence intensity. Furthermore, the spiral structure can generate turbulence at relatively low Reynolds numbers, such as 500 to 1800 (non-spiral structures require higher Reynolds numbers), thereby significantly improving the heat transfer coefficient. For example, the comprehensive heat transfer system of the spiral cold pipe provided in this application can reach 2 to 3 times that of the existing tubular type. On the other hand, the spiral structure of the cold pipe can support countercurrent heat exchange between two fluids throughout the entire process, ensuring that at the same inlet and outlet temperatures, its logarithmic coefficient remains constant. The mean temperature difference (LMTD) is higher than that of parallel or baffled designs, making it suitable for efficient recovery of low-temperature heat sources. Furthermore, the spiral structure of the cold tube disperses the load through interlayer mechanical coupling, giving it better tensile strength at ultra-low temperatures such as -196℃. For example, its tensile strength at ultra-low temperatures is 12.69% higher than that at room temperature, while traditional non-bonded straight tube structures are prone to large deformation and failure at low temperatures. Moreover, the spiral structure of the cold tube makes its axial and radial temperature distribution more uniform. For example, it can reach thermal equilibrium 3 hours earlier than hollow straight tube structures, which can significantly reduce the accuracy loss caused by thermal deformation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the purification apparatus, collection system, and reaction system provided in the embodiments of this application;

[0023] Figure 2 A flowchart illustrating a control method according to another embodiment of this application;

[0024] Figure 3 This is a schematic diagram of a carbonate conversion device provided in another embodiment of this application.

[0025] Explanation of reference numerals in the attached figures

[0026] 1000. Carbonate conversion equipment; 100. Purification device; 1. Refrigeration unit; 1a. Cold head; 2. Cold pipe; 2a. Inlet; 2b. Outlet; 21. Coil; 22. Inlet pipe; 23. Outlet pipe; 3. Shell; 3a. Refrigeration chamber; 4. First switching valve; 5. Second switching valve; 6. Outer shell; 7. Vacuum pump; 71. Pump body; 72. Isolation valve; 73. Vacuum pipeline; 8. Chiller; 9. Metal joint; 200. Collection system; 300. Reaction system; 400. Vacuum system; 500. Pressure gauge. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0028] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. The terms "first," "second," etc., used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly including at least one feature. In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] One embodiment of this application provides a carbon dioxide purification apparatus 100, please refer to... Figure 1 and Figure 3 The purification device 100 includes a refrigerator 1 and a cold pipe 2. The refrigerator 1 has a cold head 1a, which is used to release cold energy. A portion of the cold pipe 2 is spirally sleeved around the outer periphery of the cold head 1a. The cold pipe 2 has an inlet 2a and an outlet 2b. The raw material gas containing carbon dioxide enters from the inlet 2a, and the outlet 2b is used for exhaust. The refrigerator 1 can adjust the temperature inside the cold pipe 2 according to the condensation point of each gas in the raw material gas.

[0030] Refrigeration unit 1 refers to a device that can adjust the temperature inside the cold pipe 2 according to the condensation point of each gas.

[0031] The outlet 2b can be used to discharge purified carbon dioxide and impurity gases in the raw material gas.

[0032] The carbon dioxide purification device 100 provided in this application embodiment uses a refrigerator 1 for temperature regulation. Compared with the prior art of immersing in a liquid nitrogen container, the temperature inside the cold pipe 2 can be flexibly adjusted to target gases with different condensation points in the raw material gas. This results in better temperature control accuracy and purification effect.

[0033] By spirally winding the cold pipe 2 around the outer circumference of the cold head 1a, on the one hand, the spiral structure of the cold pipe 2 can induce the gas to generate rotational flow, thus significantly enhancing the turbulence intensity through centrifugal force. Furthermore, the spiral structure can generate turbulence at relatively low Reynolds numbers, such as 500 to 1800 (while non-spiral structures require higher Reynolds numbers), thereby greatly improving the heat transfer coefficient. For example, the integrated heat transfer system of the spiral cold pipe 2 provided in this embodiment can reach 2 to 3 times that of the tubular type in the prior art. On the other hand, the spiral structure of the cold pipe 2 can support countercurrent heat exchange between the two fluids throughout the entire process, enabling it to achieve the same inlet and outlet temperatures for heat transfer. The linear mean temperature difference (LMTD) is higher than that of parallel or baffled designs, making it suitable for efficient recovery of low-temperature heat sources. Furthermore, the spiral structure of the cold tube 2 disperses the load through interlayer mechanical coupling, giving it better tensile strength at ultra-low temperatures such as -196℃. For example, its tensile strength at ultra-low temperatures is 12.69% higher than that at room temperature, while traditional non-bonded straight tube structures are prone to large deformation and failure at low temperatures. Moreover, the spiral structure of the cold tube 2 makes its axial and radial temperature distribution more uniform. For example, it can reach thermal equilibrium 3 hours earlier than hollow straight tube structures, which can significantly reduce the accuracy loss caused by thermal deformation.

[0034] For example, in one embodiment, the cold head 1a can be designed according to the spiral diameter requirements of the cold pipe 2.

[0035] In one embodiment, please refer to Figure 1 The purification device 100 includes a housing 3, which forms a refrigeration chamber 3a, and a cold head 1a is disposed in the refrigeration chamber 3a.

[0036] The housing 3 can be a kit for the cold head 1a, which can be fitted inside to reduce heat exchange with the outside.

[0037] Here, by forming a cooling cavity 3a inside the housing 3, the cold head 1a of the refrigerator 1 and part of the cold pipe 2 can be set in the cooling cavity 3a, which can keep the cold head 1a and part of the cold pipe 2 in a low temperature constant temperature state. In this way, the leakage of cold in the cooling cavity 3a can be reduced and the temperature accuracy of the cooling cavity 3a can be improved.

[0038] In one embodiment, the refrigerator 1 is a pulse tube refrigerator.

[0039] Here, a pulse tube refrigerator is used, which utilizes the principle of gas expansion refrigeration. On the one hand, the expansion refrigeration process is achieved entirely within the pulse tube through gas oscillation, eliminating the need for mechanical moving parts such as pistons and valves at the cold end (low-temperature zone). This not only significantly extends the service life of the refrigerator 1 but also reduces operating noise. On the other hand, it boasts high refrigeration efficiency. For example, when providing 600W of refrigeration capacity in the liquid nitrogen temperature zone (77K), its relative Carnot efficiency reaches 19%, which is 30% higher than similar products. Furthermore, the pulse tube refrigerator uses inert gases such as helium as the working fluid, replacing traditional Freon refrigerants, thus reducing ozone layer depletion and the greenhouse effect. Moreover, the pulse tube refrigerator isolates the compression chamber and the refrigeration chamber through an elastic membrane or magnetic coupling, reducing lubricating oil contamination of the refrigerant (as in the case of an oil-lubricated compressor), balancing cost and cleanliness.

[0040] In one embodiment, the cold head 1a is made of oxygen-free copper.

[0041] Here, the material of the cold head 1a is oxygen-free copper. On the one hand, oxygen-free copper can maintain high toughness and mechanical strength at extremely low temperatures, reducing the risk of brittle fracture and ensuring reliable cooling of the cold head 1a during long-term operation, reducing failures and maintenance needs. On the other hand, oxygen-free copper has high thermal conductivity, which can efficiently transfer and dissipate heat, improving the overall energy efficiency and cooling speed of the refrigeration system. Furthermore, oxygen-free copper has extremely low oxygen content and few impurities, which can effectively resist oxidation and corrosion in humid environments, extending the service life of the cold head 1a and reducing leakage or performance degradation caused by corrosion.

[0042] In one embodiment, please refer to Figure 1 The cooling pipe 2 includes a coil 21, an inlet pipe 22, and an outlet pipe 23. The coil 21 is spirally wound around the cooling head 1a. The inlet pipe 22 and the outlet pipe 23 are respectively connected to one end of the coil 21 and extend out of the housing 3. The inlet pipe 22 has an inlet 2a, and the outlet pipe 23 has an outlet 2b. The purification device 100 includes a first switching valve 4 and a second switching valve 5. The first switching valve 4 is disposed in the inlet pipe 22, and the second switching valve 5 is disposed in the outlet pipe 23.

[0043] The coil 21 can be a spiral low-temperature column, coiled around the outer periphery of the cold head 1a.

[0044] The inlet pipe 22 and the outlet pipe 23 are respectively connected to one end of the coil 21 and extend out of the housing 3. The inlet pipe 22 has an inlet 2a and the outlet pipe 23 has an outlet 2b. That is to say, the raw material gas can enter the coil 21 through the inlet 2a of the inlet pipe 22. After purification and impurity removal in the coil 21, the impurity gas can be extracted and separated through the outlet 2b of the outlet pipe 23, and carbon dioxide can be collected through the outlet 2b.

[0045] The first switching valve 4 and the second switching valve 5 can both be gas shut-off valves.

[0046] Here, by setting the first switching valve 4 and the second switching valve 5, the intake and exhaust of air can be controlled, and then impurity gases and carbon dioxide can be separated and collected to improve the purity of carbon dioxide.

[0047] In one embodiment, the diameter of the inlet pipe 22 and / or the outlet pipe 23 can be the same as the diameter of the coil 21. This can reduce the problem of uneven flow distribution caused by different diameters, improve the uniform distribution of gas in the coil 21, and improve the purification accuracy of carbon dioxide.

[0048] In one embodiment, the inlet pipe 22 and / or outlet pipe 23 can be made of stainless steel. Using stainless steel here has several advantages: firstly, it has high tensile strength, making it less prone to breakage due to external impact, resulting in a long service life and significantly reducing replacement and maintenance costs; secondly, stainless steel has excellent corrosion resistance and stability, resisting corrosion from acids, alkalis, chlorides, and seawater, and its inner wall is less prone to scaling or rusting, reducing the generation of harmful substances during long-term use and improving purification accuracy; thirdly, the smooth inner wall of stainless steel reduces airflow resistance, minimizes energy loss caused by turbulence, and reduces impurity adhesion, improving gas flow uniformity and purification efficiency.

[0049] In one embodiment, please refer to Figure 1 The purification device 100 includes a housing 6 and a vacuum pump 7. The housing 3, the inlet pipe 22 and the outlet pipe 23 are all located inside the housing 6. The vacuum pump 7 is used to adjust the vacuum level inside the housing 6.

[0050] For example, the vacuum pump 7 includes a pump body 71, an isolation valve 72, and a vacuum pipeline 73. The pipeline connects the pump body 71 and the housing 3. The isolation valve 72 is disposed on the vacuum pipeline 73 and is used to shut off or connect the pump body 71 and the housing 6. The housing 3, the inlet pipe 22, and the outlet pipe 23 can all be disposed inside the housing 6.

[0051] For example, vacuum line 73 can be a bellows.

[0052] Here, by setting up the outer casing 6 and the vacuum pump 7, the vacuum level inside the outer casing 6 can be adjusted so that the outer casing 6 is in a vacuum state. This can reduce the temperature fluctuation caused by cold leakage from the casing 3 and improve the accuracy of temperature control.

[0053] In one exemplary embodiment, the housing 6 may be designed and manufactured according to the dimensions of the coil 21 and the cold head 1a.

[0054] In one embodiment, the outer casing 6 is made of stainless steel.

[0055] Here, the outer shell 6 is made of stainless steel. On the one hand, it can withstand extreme temperature ranges and maintain stable mechanical properties during gas purification, reducing thermal deformation or brittleness. On the other hand, it has strong sealing properties, reducing the possibility of gas leakage. Furthermore, stainless steel is easy to weld and process, and ensures vacuum.

[0056] In one embodiment, the purification apparatus 100 includes a venting valve disposed on the housing 6.

[0057] This makes it easier to release the vacuum inside the outer casing 6.

[0058] In one embodiment, please refer to Figure 1 The purification device 100 includes a chiller 8, which is connected to the refrigeration unit 1 via a pipe.

[0059] In this way, the chiller 8 can dissipate heat from the refrigeration unit 1, ensuring that the refrigeration unit 1 works efficiently.

[0060] In one embodiment, the purification apparatus 100 includes a controller that is communicatively connected to the refrigerator 1. The controller can adjust the cooling temperature of the refrigerator 1 for convenient temperature control.

[0061] One embodiment of this application provides a carbonate conversion device; please refer to... Figure 3 The carbonate conversion equipment includes a collection system 200, a reaction system 300, and a carbon dioxide purification device 100 as described in any of the following embodiments. The inlet 2a is connected to the reaction system 300, and the outlet 2b is connected to the collection system 200.

[0062] For example, the air inlet 2a of the air inlet pipe 22 can be connected to the pipeline of the reaction system 300 through the metal connector 9, and the air outlet 2b of the air outlet pipe 23 can be connected to the collection system 200 through the metal connector 9.

[0063] The reaction system 300 refers to equipment capable of reacting to produce a raw material gas containing carbon dioxide.

[0064] Collection system 200 refers to equipment used for collecting gases.

[0065] The carbonate conversion equipment provided in this application, based on the advantages of the carbon dioxide purification device 100 described above, also features high purity of the carbon dioxide produced.

[0066] As an example, in one embodiment, please refer to Figure 3The carbonate conversion equipment includes a vacuum system 400 and a pressure gauge 500. The vacuum system 400 is connected to the collection system 200 and the purification device 100 via a pipeline. The pressure gauge 500 is connected to the purification device 100 via a pipeline between the reaction system 300 and the purification device 100. The vacuum system 400 can be used to remove residual gas in the pipeline, and the pressure gauge 500 is used to monitor the gas pressure in the pipeline between the reaction system 300 and the gas inlet 2a.

[0067] In another aspect, this application provides a control method; please refer to [link / reference needed]. Figure 2 The purification apparatus 100 applied in any of the above embodiments includes a control method comprising:

[0068] S1. The temperature inside the cold pipe is adjusted by the refrigeration machine to purify the carbon dioxide in the cold pipe.

[0069] Here, by adjusting the temperature of the cold pipe 2 through the refrigerator 1, condensation and / or vaporization operations can be performed on gases with different condensation points to improve the purification accuracy of carbon dioxide.

[0070] In one embodiment, the control method includes:

[0071] S11. Adjust the temperature inside the cold pipe to a preset temperature so that the mixed gas containing carbon dioxide in the raw material gas above the preset temperature condenses, and extract and separate the uncondensed impurity gas.

[0072] For example, the raw material gas includes carbon dioxide, oxygen, hydrogen, carbon monoxide, helium, nitrogen, phosphine, hydrogen sulfide, and water vapor. The preset temperature can be 77K. After adjusting the temperature inside the cold pipe 2 to 77K, the uncondensed impurity gas may include oxygen, hydrogen, carbon monoxide, helium, and nitrogen, and the condensed mixed gas may include carbon dioxide, phosphine, hydrogen sulfide, and water vapor. The uncondensed impurities are extracted and separated by the collection system 200 and then removed.

[0073] S12. Based on the condensation point of each impurity gas in the mixed gas and the condensation point of carbon dioxide, the temperature inside the cold pipe is gradually increased to separate the impurity gases and carbon dioxide from the mixed gas.

[0074] For example, phosphine has a freezing point of 139.65 K, hydrogen sulfide has a freezing point of 197.65 K, carbon dioxide has a freezing point of 216.55 K, and water vapor has a freezing point of 275.15 K. Phosphine and hydrogen sulfide impurity gases are slowly released and removed in order of increasing freezing point. Then, the temperature is raised to 216.55 K to slowly release carbon dioxide, which is collected by the collection system 200. The water is frozen in a spiral cryogenic column. Thus, the carbon dioxide is successfully purified and completely collected.

[0075] Here, the temperature inside the cold pipe 2 is first lowered to a preset temperature, causing the carbon dioxide-containing mixed gas in the raw material gas above the preset temperature to condense. Then, the uncondensed gas is extracted for the first purification. Next, based on the condensation points of each impurity gas in the mixed gas and the condensation point of carbon dioxide, the temperature inside the cold pipe 2 is gradually increased to separate the impurity gases and carbon dioxide in the mixed gas for multi-stage purification. In this way, by precisely controlling the temperature, the impurity gases of the mixed components in the generated carbon dioxide are removed more thoroughly, while ensuring that the carbon dioxide content is not affected and can be completely collected, avoiding the fractionation effect.

[0076] Another aspect of this application provides a process for collecting carbon dioxide gas using a purification device 100, as detailed below:

[0077] 1. Installation of cooling pipe 2: Wrap the coil 21 around the cooling head 1a, then connect the inlet pipe 22 and the outlet pipe 23 to one end of the coil 21 respectively. Install the cooling head 1a into the housing 3, then install the outer shell 6. Finally, connect the other ends of the inlet pipe 22 and the outlet pipe 23 to the collection system 200 and the reaction system 300 through the metal connector 9. Install the first switch valve 4 on the inlet pipe 22 and the second switch valve 5 on the outlet pipe 23.

[0078] 2. Vacuuming: Start the pump body 71 and open the isolation valve 72 to evacuate the vacuum level inside the outer casing 6 to the set value and keep it constant.

[0079] 3. Turn on chiller 8: Turn on chiller 8 to make the water circulation system of chiller 1 work normally.

[0080] 4. Turn on Refrigeration Unit 1: Turn on the controller of Refrigeration Unit 1, set the preset temperature, and start Refrigeration Unit 1.

[0081] 5. Gas purification: Open the first switch valve 4, set the preset temperature to 70K, condense the mixed gas containing carbon dioxide generated by the reaction in the coil 21, close the first switch valve 4, open the second switch valve 5, and the vacuum pump of the collection system 200 removes the uncondensed impurity gas. The temperature inside the cold tube 2 is raised in a stepwise manner to accurately remove the impurity gas.

[0082] 6. Gas collection: Set the temperature control value to 193K and use the collection system 200 to collect carbon dioxide in the coil 21.

[0083] Application results show that the purification device 100 of this application embodiment has the advantages of high temperature control accuracy, stable temperature, wide controllable temperature range, simple structure, convenient use, and no need to replenish liquid nitrogen. It has broad application prospects in carbon dioxide gas purification and other occasions that require precise temperature control.

[0084] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. All modifications, equivalent substitutions, improvements, etc., within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A carbon dioxide purification apparatus, characterized in that, include: A refrigeration unit having a cold head for releasing cold energy; A cooling pipe, part of which is spirally sleeved around the outer periphery of the cold head, has an inlet and an outlet. Raw material gas containing carbon dioxide enters through the inlet, and the outlet is used for exhaust. The refrigeration unit can adjust the temperature inside the cooling pipe according to the condensation point of each gas in the raw material gas.

2. The purification apparatus according to claim 1, characterized in that, The refrigerator is a pulse tube refrigerator; and / or, the cold head is made of oxygen-free copper.

3. The purification apparatus according to claim 1, characterized in that, The purification device includes a housing, which forms a refrigeration chamber, and the cold head is disposed in the refrigeration chamber.

4. The purification apparatus according to claim 3, characterized in that, The cooling pipe includes a coil, an inlet pipe, and an outlet pipe. The coil is spirally wound around the cooling head. The inlet pipe and the outlet pipe are respectively connected to one end of the coil and extend out of the housing. The inlet pipe has an inlet port, and the outlet pipe has an outlet port. The purification device includes a first switching valve and a second switching valve. The first switching valve is disposed in the inlet pipe, and the second switching valve is disposed in the outlet pipe.

5. The purification apparatus according to claim 4, characterized in that, The purification device includes a housing and a vacuum pump. The housing, the inlet pipe, and the outlet pipe are all disposed inside the housing. The vacuum pump is used to adjust the vacuum level inside the housing.

6. The purification apparatus according to claim 5, characterized in that, The outer casing is made of stainless steel; and / or the purification device includes a venting valve disposed on the outer casing.

7. The purification apparatus according to claim 1, characterized in that, The purification device includes a chiller, which is connected to the refrigeration unit via a pipeline.

8. A carbonate conversion device, characterized in that, The device includes a collection system, a reaction system, and a carbon dioxide purification apparatus according to any one of claims 1 to 7, wherein the inlet is connected to the reaction system and the outlet is connected to the collection system.

9. A control method, characterized in that, The control method, applied to the purification apparatus according to any one of claims 1 to 7, comprises: The temperature inside the cold pipe is adjusted by the refrigeration unit to purify the carbon dioxide in the cold pipe.

10. The control method according to claim 9, characterized in that, The control method includes: The temperature inside the cooling pipe is adjusted to a preset temperature so that the mixed gas containing carbon dioxide in the raw material gas above the preset temperature condenses, and the uncondensed impurity gas is extracted and separated. Based on the condensation points of the impurity gases in the mixed gas and the condensation point of the carbon dioxide, the temperature inside the cold pipe is gradually increased to separate the impurity gases and the carbon dioxide from the mixed gas.

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