Carbon dioxide purification device and purification method

Abstract

The present invention relates to the technical field of carbon dioxide purification, and in particular to a carbon dioxide purification device and method. The purification device comprises a supply unit, a distillation tower, a first heat exchanger, a second heat exchanger, an air cooler, an adsorption unit, a heating unit, and a diaphragm compressor. The distillation tower is connected to the supply unit, which is used to supply a liquid carbon dioxide crude product to the main area. The first heat exchanger is used to remove impurities from the gaseous area before re-discharging it into the gaseous area and to receive the refrigerated liquid discharged from the liquid area. The second heat exchanger is connected to the first heat exchanger, the air cooler, the diaphragm compressor, and an external gas storage container. The adsorption unit is connected to the air cooler and the heating unit. The technical solution provided by the present invention can reduce energy waste.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide purification, and in particular to a carbon dioxide purification device and a carbon dioxide purification method. Background Art

[0002] Carbon dioxide is a valuable resource, widely used in chemical, mechanical, industrial, food, and pharmaceutical industries. Crude carbon dioxide contains a significant amount of impurities such as nitrogen, oxygen, water vapor, and hydrocarbon compounds, requiring purification before use.

[0003] In related technologies, carbon dioxide usually needs to be heated and cooled repeatedly, which results in a large amount of energy waste.

[0004] Therefore, there is an urgent need for a carbon dioxide purification device and purification method to solve the above problems. Summary of the Invention

[0005] The embodiments of the present invention describe a carbon dioxide purification device and a purification method, which can reduce energy waste.

[0006] In a first aspect, one embodiment of the present invention provides a carbon dioxide purification device, comprising a supply unit, a distillation column, a first heat exchanger, a second heat exchanger, an air cooler, an adsorption unit, a heating unit, and a diaphragm compressor, wherein:

[0007] The distillation tower includes a gaseous zone, a main zone, and a liquid zone connected in sequence from top to bottom along the height direction, the main zone is connected to the supply unit, and the supply unit is used to supply a liquid carbon dioxide crude product to the main zone. A first spiral coil is provided in the liquid zone;

[0008] The first heat exchanger is connected to the gaseous region and the liquid region respectively, and is used to remove impurities from the gas discharged from the gaseous region and then discharge it back into the gaseous region, and is used to receive the refrigerated liquid discharged from the liquid region, so as to use the liquid to condense the gas discharged from the gaseous region;

[0009] The second heat exchanger has a heat absorption pipeline and a heat release pipeline. The inlet end of the heat absorption pipeline is connected to the outlet end of the first heat exchanger, and the outlet end of the heat absorption pipeline is connected to the inlet end of the air cooler.

[0010] The adsorption unit is connected to the outlet end of the air cooler and the heating unit respectively, and is used to perform secondary impurity removal on the gas entering the adsorption unit;

[0011] The first spiral coil is connected to the heating unit and the inlet end of the diaphragm compressor respectively, and is used to receive the gas heated by the heating unit to heat the liquid in the liquid zone using the gas;

[0012] The inlet end of the heat release pipeline is connected to the outlet end of the diaphragm compressor, and the outlet end of the heat release pipeline is connected to an external gas storage container.

[0013] In a second aspect, one embodiment of the present invention provides a method for purifying carbon dioxide, based on the carbon dioxide purification device described in the above embodiment, the method comprising:

[0014] supplying a liquid carbon dioxide crude product to the main area using the supply unit;

[0015] heating the liquid in the liquid zone by using the gas heated by the heating unit and received by the first spiral coil;

[0016] The gas discharged from the gaseous region is subjected to a primary impurity removal process using the first heat exchanger, and the gas after the primary impurity removal process is condensed using the refrigerated liquid discharged from the liquid region, so as to discharge the condensed liquid back into the gaseous region;

[0017] Using the second heat exchanger to heat the liquid discharged from the first heat exchanger, and using the air cooler to further heat the gas discharged from the second heat exchanger;

[0018] The adsorption unit is used to perform secondary impurity removal on the gas discharged from the air cooler; wherein the gas subjected to secondary impurity removal includes at least one of sulfur dioxide, formaldehyde, and methanol;

[0019] The diaphragm compressor is used to compress the gas discharged from the first spiral coil, and the second heat exchanger is used to cool the gas discharged from the diaphragm compressor, so that the cooled gas is filled into an external gas storage container.

[0020] According to the carbon dioxide purification device and method provided by the embodiments of the present invention, by providing a first heat exchanger, the gas discharged from the gaseous region can be condensed using the refrigerated liquid discharged from the liquid region. By providing a second heat exchanger, the heat of the gas discharged from the diaphragm compressor can be effectively utilized to more quickly heat the liquid discharged from the first heat exchanger, while also ensuring that the cooled gas can be more safely charged into an external gas storage container. By providing a first spiral coil in the liquid region, the heat of the gas discharged from the heating unit can be effectively utilized to more efficiently heat the crude liquid carbon dioxide product. Therefore, the above technical solution can reduce energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic structural diagram of a carbon dioxide purification device according to one embodiment is shown;

[0023] Figure 2 for Figure 1 A partial enlarged view of the carbon dioxide purification device shown.

[0024] Reference numerals:

[0025] 10- Gas storage container;

[0026] 1- supply unit;

[0027] 11-liquid inlet pipeline;

[0028] 12-first flow regulating valve;

[0029] 2-distillation tower;

[0030] 21-gaseous zone;

[0031] 211-first visual window;

[0032] 22-main area;

[0033] 23-Liquid zone;

[0034] 231-first spiral coil;

[0035] 232-second visual window;

[0036] 24-Expansion valve;

[0037] 3-first heat exchanger;

[0038] 31-inner shell;

[0039] 32-housing;

[0040] 33-first pipeline;

[0041] 34-second pipeline;

[0042] 35- second spiral coil;

[0043] 36- second flow control valve;

[0044] 37- Second flow meter;

[0045] 4- Second heat exchanger;

[0046] 41-first flow meter;

[0047] 42-pressure gauge;

[0048] 5- air cooler;

[0049] 6-adsorption unit;

[0050] 7- Heating unit;

[0051] 8-Diaphragm compressor;

[0052] 9-Inflatable unit. DETAILED DESCRIPTION

[0053] The solution provided by the present invention is described below with reference to the accompanying drawings.

[0054] like Figure 1 As shown, an embodiment of the present invention provides a carbon dioxide purification device, which includes a supply unit 1, a distillation tower 2, a first heat exchanger 3, a second heat exchanger 4, an air cooler 5, an adsorption unit 6, a heating unit 7 and a diaphragm compressor 8, wherein:

[0055] The distillation tower 2 includes a gaseous zone 21, a main zone 22, and a liquid zone 23 connected in sequence from top to bottom in the height direction. The main zone 22 is connected to the supply unit 1, which is used to supply a liquid crude carbon dioxide product to the main zone 22. A first spiral coil 231 is provided in the liquid zone 23.

[0056] The first heat exchanger 3 is connected to the gaseous region 21 and the liquid region 23, respectively, and is used to remove impurities from the gas discharged from the gaseous region 21 and then discharge it back into the gaseous region 21, and to receive the refrigerated liquid discharged from the liquid region 23, so as to use the liquid to condense the gas discharged from the gaseous region 21;

[0057] The second heat exchanger 4 has a heat absorption pipeline and a heat release pipeline. The inlet end of the heat absorption pipeline is connected to the outlet end of the first heat exchanger 3, and the outlet end of the heat absorption pipeline is connected to the inlet end of the air cooler 5.

[0058] The adsorption unit 6 is connected to the outlet end of the air cooler 5 and the heating unit 7 respectively, and is used to perform secondary impurity removal on the gas entering the adsorption unit 6;

[0059] The first spiral coil 231 is connected to the inlet end of the heating unit 7 and the diaphragm compressor 8 respectively, and is used to receive the gas heated by the heating unit 7 to heat the liquid in the liquid zone 23 using the gas;

[0060] The inlet end of the heat release pipeline is connected to the outlet end of the diaphragm compressor 8 , and the outlet end of the heat release pipeline is connected to the external gas storage container 10 .

[0061] In this embodiment, the provision of a first heat exchanger 3 allows the refrigerated liquid discharged from the liquid region 23 to condense the gas discharged from the gaseous region 21. The provision of a second heat exchanger 4 effectively utilizes the heat of the gas discharged from the diaphragm compressor 8 to more quickly heat the liquid discharged from the first heat exchanger 3, while also ensuring that the cooled gas can be more safely charged into the external gas storage container 10. The provision of a first spiral coil 231 within the liquid region 23 effectively utilizes the heat of the gas discharged from the heating unit 7 to more efficiently heat the liquid crude carbon dioxide product. Therefore, the above technical solution can reduce energy waste.

[0062] It is understandable that if the gas discharged from the diaphragm compressor 8 is directly charged into the external gas storage container 10, due to the high temperature and pressure of the gas, this method of direct charging may cause the gas storage container 10 to explode. Therefore, from the perspective of safety and reducing energy waste, the inventors creatively installed a second heat exchanger 4 between the first heat exchanger 3 and the air cooler 5.

[0063] In addition, since the efficient adsorption temperature range of the adsorption unit 6 is generally room temperature, an air cooler 5 is provided before the adsorption unit 6 to effectively ensure that the temperature of the gas entering the adsorption unit 6 is room temperature. In some embodiments, the adsorption unit 6 may adopt an activated carbon adsorption method or a molecular sieve adsorption method, which is not specifically limited herein.

[0064] In some embodiments, the supply unit 1 may be a storage tank, a steel cylinder, a Dewar tank, etc., which are not specifically limited herein.

[0065] In one embodiment of the present invention, a plurality of liquid inlet pipelines 11 arranged along the height direction of the distillation tower 2 are connected between the supply unit 1 and the main area 22 , and each liquid inlet pipeline 11 is provided with a first flow regulating valve 12 .

[0066] In this embodiment, since the temperature gradient of the main area 22 decreases from top to bottom, in order to ensure the temperature balance in the main area 22 and further obtain a higher purity carbon dioxide product, it can be considered to connect multiple liquid inlet pipelines 11 arranged along the height direction of the distillation tower 2 between the supply unit 1 and the main area 22, so as to determine the target liquid inlet pipeline 11 according to the actual temperature of the supply unit 1, so that the actual temperature of the supply unit 1 is adapted to the corresponding temperature of the main area 22, that is, to ensure the temperature balance in the main area 22.

[0067] In one embodiment of the present invention, an expansion valve 24 is provided between the first heat exchanger 3 and the liquid region 23 , and the expansion valve 24 is used to refrigerate the liquid discharged from the liquid region 23 .

[0068] In this embodiment, by arranging an expansion valve 24 between the first heat exchanger 3 and the liquid zone 23, the cold energy generated by the liquid refrigeration discharged from the liquid zone 23 can be used to condense the gas after the impurities are removed once, thereby reducing the refrigeration cost expenditure; at the same time, since the volume of the expansion valve 24 is very small, the area it occupies is very small.

[0069] It should be noted that while the expansion valve 24 has the advantages described above, it also has certain drawbacks. For example, before the purification device is started, the device's pipelines must be evacuated to ensure the high purity of the carbon dioxide product. However, due to the expansion valve 24, if the supply unit 1 is used to directly supply the liquid crude carbon dioxide product to the main area 22 after evacuation, dry ice will form at the rear end of the expansion valve 24 (or even at the front end of the expansion valve 24 due to the thermal conductivity of the expansion valve 24) shortly after the purification device is started, causing pipeline blockage, which is very disadvantageous. The usual approach to solving this problem is to shut down the device and wait for several hours to allow the external ambient temperature to melt the dry ice. However, dry ice usually undergoes a direct sublimation reaction, causing a sharp increase in pressure in some sections of the pipeline, which may cause pipeline leakage, which is also very disadvantageous. Therefore, solving this technical problem is imperative.

[0070] In one embodiment of the present invention, it further comprises an air filling unit 9, which is connected to the inlet end of the diaphragm compressor 8;

[0071] The charging unit 9 is used to charge carbon dioxide gas into the inlet end of the diaphragm compressor 8 after the purification device is vacuumed, so that the charged carbon dioxide gas fills the pipeline and components between the expansion valve 24 and the inlet end of the diaphragm compressor 8; wherein the components include the first heat exchanger 3, the second heat exchanger 4, the adsorption unit 6 and the first spiral coil 231.

[0072] In this embodiment, the inventors creatively discovered during the research and development process that if carbon dioxide gas of a certain pressure is filled into the pipes and components at the rear end of the expansion valve 24 after vacuuming, the pressure difference before and after the expansion valve 24 will not be too large when the power is turned on, which can effectively solve the problem of dry ice generation at the rear end of the expansion valve 24.

[0073] In one embodiment of the present invention, when the injected carbon dioxide gas fills the pipes and components between the expansion valve 24 and the inlet end of the diaphragm compressor 8 , the pressure at the outlet end of the expansion valve 24 is one third to one half of the pressure in the supply unit 1 .

[0074] In some embodiments, the pressure in the supply unit 1 may be 20 atmospheres, and the pressure at the outlet of the expansion valve 24 may be 10 atmospheres, which is not specifically limited herein.

[0075] Regarding the aforementioned issue of dry ice generation due to the installation of the expansion valve 24, in order to solve this technical problem, the inventors creatively discovered that the opening of the first flow regulating valve 12 can be further adjusted by real-time monitoring of the current flow and pressure of the pipeline at the rear end of the expansion valve 24, thereby effectively solving this technical problem.

[0076] Specifically, in one embodiment of the present invention, a control unit (not shown) is further included. A first flow meter 41 and a pressure gauge 42 are provided on the pipeline between the second heat exchanger 4 and the air cooler 5. The control unit is electrically connected to the first flow regulating valve 12, the first flow meter 41, and the pressure gauge 42, respectively.

[0077] The control unit is used to control the opening of the first flow regulating valve 12 according to the flow signal sent by the first flow meter 41 and the pressure signal sent by the pressure gauge 42 .

[0078] In one embodiment of the present invention, the control unit controls the opening of the first flow control valve 12 by the following formula:

[0079]

[0080] Wherein, q1 represents the flow rate detected by the first flow meter 41, q0 represents the preset flow rate, p1 represents the pressure detected by the pressure gauge 42, p0 represents the preset pressure, and k represents the preset threshold value;

[0081] If the result of the left formula of the above formula is greater than the preset threshold, the control unit controls the opening of the first flow regulating valve 12 to gradually increase; otherwise, the control unit controls the opening of the first flow regulating valve 12 to gradually decrease.

[0082] In this embodiment, since the flow rate decreases instantaneously when dry ice is generated and a blockage occurs, and the response time of pressure relative to the flow rate is slightly longer, this principle can be used to increase the specific gravity of the flow rate. For example, the difference between the flow rate detected by the first flow meter 41 and the preset flow rate can be subjected to an exponential operation of a natural constant. At the same time, this principle can be used to reduce the specific gravity of the pressure. For example, the difference between the pressure detected by the pressure meter 42 and the preset pressure can be subjected to a logarithmic operation with a natural constant as the base. This configuration enables the control unit to adjust the opening of the first flow control valve 12.

[0083] like Figure 2As shown, in one embodiment of the present invention, the first heat exchanger 3 includes an inner shell 31 and an outer shell 32. The inner shell 31 has a first cavity. A second cavity is formed between the inner shell 31 and the outer shell 32. The first cavity is connected to the liquid region 23. The upper part of the second cavity is connected to the gaseous region 21 through a first pipe 33. The lower part of the second cavity is connected to the gaseous region 21 through a second pipe 34.

[0084] The end of the first pipeline 33 near the outer shell 32 is connected in sequence with a second spiral coil 35, a second flow regulating valve 36 and a second flow meter 37. The second flow regulating valve 36 is used to adjust the gas flow flowing through the second spiral coil 35 to control the reading of the second flow meter 37 to be between 1L / min and 2L / min.

[0085] In this embodiment, by setting a second spiral coil 35 at the end of the first pipeline 33 near the outer shell 32, the ambient temperature can be effectively absorbed to discharge part of the impurity gas (such as oxygen), and by setting a second flow regulating valve 36 and a second flow meter 37, the discharged carbon dioxide product gas can be minimized while discharging part of the impurity gas.

[0086] In one embodiment of the present invention, a first visual window 211 is provided outside the gaseous region 21 , and a second visual window 232 is provided outside the liquid region 23 .

[0087] In this embodiment, the provision of first visual window 211 facilitates observation of the reflux rate of second pipeline 34 through first visual window 211; the provision of second visual window 232 facilitates observation of the liquid level of carbon dioxide through second visual window 232, thereby inferring the evaporation rate of carbon dioxide. Therefore, the provision of first visual window 211 and second visual window 232 effectively assists the operator in real-time adjustment of the evaporation rate and reflux rate of distillation column 2, thereby obtaining a higher-purity carbon dioxide product.

[0088] In addition, an embodiment of the present invention further provides a method for purifying carbon dioxide, based on the carbon dioxide purification device mentioned in the above embodiment, the method comprising:

[0089] Supplying a liquid carbon dioxide crude product to the main area 22 using the supply unit 1;

[0090] The gas heated by the heating unit 7 and received by the first spiral coil 231 is used to heat the liquid in the liquid zone 23;

[0091] The gas discharged from the gaseous region 21 is subjected to a primary impurity removal process using the first heat exchanger 3, and the gas after the primary impurity removal process is condensed using the refrigerated liquid discharged from the liquid region 23, so that the condensed liquid is discharged back into the gaseous region 21;

[0092] The second heat exchanger 4 is used to increase the temperature of the liquid discharged from the first heat exchanger 3, and the air cooler 5 is used to further increase the temperature of the gas discharged from the second heat exchanger 4;

[0093] The adsorption unit 6 is used to perform secondary impurity removal on the gas discharged from the air cooler 5; wherein the gas subjected to the secondary impurity removal includes at least one of sulfur dioxide, formaldehyde, and methanol;

[0094] The gas discharged from the first spiral coil 231 is compressed by the diaphragm compressor 8 , and the gas discharged from the diaphragm compressor 8 is cooled by the second heat exchanger 4 , so that the cooled gas is filled into the external gas storage container 10 .

[0095] It is understandable that the carbon dioxide purification method provided in this embodiment and the carbon dioxide purification device provided in the above embodiment are based on the same inventive concept, and therefore both have the same beneficial effects, which will not be described in detail here.

[0096] It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A carbon dioxide purification device, characterized in that: The invention comprises a supply unit (1), a distillation tower (2), a first heat exchanger (3), a second heat exchanger (4), an air cooler (5), an adsorption unit (6), a heating unit (7) and a diaphragm compressor (8), wherein: The distillation tower (2) comprises a gaseous zone (21), a main zone (22), and a liquid zone (23) connected in sequence from top to bottom along a height direction, the main zone (22) being connected to the supply unit (1), the supply unit (1) being used to supply a liquid carbon dioxide crude product to the main zone (22), and a first spiral coil (231) being provided in the liquid zone (23); The first heat exchanger (3) is connected to the gaseous zone (21) and the liquid zone (23) respectively, and is used to remove impurities from the gas discharged from the gaseous zone (21) and then discharge it back into the gaseous zone (21), and is used to receive the liquid discharged from the liquid zone (23) and refrigerated, so as to use the liquid to condense the gas discharged from the gaseous zone (21); The second heat exchanger (4) has a heat absorption pipeline and a heat release pipeline. The inlet end of the heat absorption pipeline is connected to the outlet end of the first heat exchanger (3), and the outlet end of the heat absorption pipeline is connected to the inlet end of the air cooler (5). The adsorption unit (6) is connected to the outlet end of the air cooler (5) and the heating unit (7) respectively, and is used for performing secondary impurity removal on the gas entering the adsorption unit (6); The first spiral coil (231) is connected to the inlet end of the heating unit (7) and the inlet end of the diaphragm compressor (8) respectively, and is used to receive the gas heated by the heating unit (7) so as to heat the liquid in the liquid zone (23) using the gas; The inlet end of the heat release pipeline is connected to the outlet end of the diaphragm compressor (8), and the outlet end of the heat release pipeline is connected to an external gas storage container (10).

2. The carbon dioxide purification device according to claim 1, characterized in that: A plurality of liquid inlet pipelines (11) arranged along the height direction of the distillation tower (2) are connected between the supply unit (1) and the main body area (22), and each of the liquid inlet pipelines (11) is provided with a first flow regulating valve (12).

3. The carbon dioxide purification device according to claim 2, characterized in that: An expansion valve (24) is provided between the first heat exchanger (3) and the liquid region (23), and the expansion valve (24) is used to refrigerate the liquid discharged from the liquid region (23).

4. The carbon dioxide purification device according to claim 3, characterized in that: It also includes an air filling unit (9), which is connected to the inlet end of the diaphragm compressor (8); The charging unit (9) is used to charge carbon dioxide gas into the inlet end of the diaphragm compressor (8) after the purification device is evacuated, so that the charged carbon dioxide gas fills the pipeline and components between the expansion valve (24) and the inlet end of the diaphragm compressor (8); wherein the components include a first heat exchanger (3), the second heat exchanger (4), the adsorption unit (6) and the first spiral coil (231).

5. The carbon dioxide purification device according to claim 4, characterized in that: When the injected carbon dioxide gas fills the pipes and components between the expansion valve (24) and the inlet end of the diaphragm compressor (8), the pressure at the outlet end of the expansion valve (24) is one third to one half of the pressure in the supply unit (1).

6. The carbon dioxide purification device according to claim 3, characterized in that: The system further comprises a control unit, wherein a first flow meter (41) and a pressure meter (42) are provided on the pipeline between the second heat exchanger (4) and the air cooler (5), and the control unit is electrically connected to the first flow regulating valve (12), the first flow meter (41) and the pressure meter (42), respectively; The control unit is used to control the opening of the first flow regulating valve (12) according to the received flow signal sent by the first flow meter (41) and the pressure signal sent by the pressure meter (42).

7. The carbon dioxide purification device according to claim 6, characterized in that: The control unit controls the opening of the first flow regulating valve (12) by the following formula: Wherein, q1 represents the flow rate detected by the first flow meter (41), q0 represents the preset flow rate, p1 represents the pressure detected by the pressure meter (42), p0 represents the preset pressure, and k represents the preset threshold value; If the calculation result of the left formula of the above formula is greater than a preset threshold value, the control unit is used to control the opening of the first flow regulating valve (12) to gradually increase; otherwise, the control unit is used to control the opening of the first flow regulating valve (12) to gradually decrease.

8. The carbon dioxide purification device according to any one of claims 1 to 7, characterized in that: The first heat exchanger (3) comprises an inner shell (31) and an outer shell (32), the inner shell (31) having a first cavity, a second cavity formed between the inner shell (31) and the outer shell (32), the first cavity being in communication with the liquid region (23), the upper portion of the second cavity being in communication with the gaseous region (21) via a first pipeline (33), and the lower portion of the second cavity being in communication with the gaseous region (21) via a second pipeline (34); The end of the first pipeline (33) close to the housing (32) is connected in sequence to a second spiral coil (35), a second flow regulating valve (36) and a second flow meter (37), wherein the second flow regulating valve (36) is used to regulate the flow of gas flowing through the second spiral coil (35) to control the reading of the second flow meter (37) to be between 1L / min and 2L / min.

9. The carbon dioxide purification device according to claim 8, characterized in that: A first visual window (211) is provided outside the gaseous region (21), and a second visual window (232) is provided outside the liquid region (23).

10. A method for purifying carbon dioxide, characterized in that: The carbon dioxide purification device according to any one of claims 1 to 9, wherein the method comprises: Using the supply unit (1) to supply a liquid carbon dioxide crude product to the main body area (22); heating the liquid in the liquid zone (23) by utilizing the gas heated by the heating unit (7) and received by the first spiral coil (231); The gas discharged from the gaseous zone (21) is subjected to a primary impurity removal process using the first heat exchanger (3), and the gas after the primary impurity removal process is condensed using the refrigerated liquid discharged from the liquid zone (23), so as to discharge the condensed liquid back into the gaseous zone (21); The liquid discharged from the first heat exchanger (3) is heated by the second heat exchanger (4), and the gas discharged from the second heat exchanger (4) is further heated by the air cooler (5); The adsorption unit (6) is used to perform secondary impurity removal on the gas discharged from the air cooler (5); Wherein, the gas for secondary impurity removal includes at least one of sulfur dioxide, formaldehyde and methanol; The diaphragm compressor (8) is used to compress the gas discharged from the first spiral coil (231), and the second heat exchanger (4) is used to cool the gas discharged from the diaphragm compressor (8), so that the cooled gas is filled into an external gas storage container (10).

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