Method and apparatus for purifying industrial off-gas liquid carbon dioxide

Abstract

A method and device for purifying liquefied carbon dioxide from industrial tail gas, which can be applied in the field of compressed air energy storage, etc. The method comprises the following steps: S1, obtaining high-pressure liquid carbon dioxide product; S2, depressurizing the high-pressure liquid carbon dioxide product to obtain low-pressure and low-temperature liquid carbon dioxide product as product output; using the cold energy generated in the throttling process of the first throttling device to provide cold energy for the purification and liquefaction of carbon dioxide in step S1; S3, passing the gaseous carbon dioxide product with increased temperature by heat exchange in step S2 into a second compression mechanism for compression, and obtaining low-pressure liquid carbon dioxide through a second throttling device. Through the above structure, the energy consumption is effectively reduced, and the problem that in the existing technology, the carbon dioxide pressure cannot be adjusted in time according to the needs in the purification process of industrial tail gas carbon dioxide, thereby causing high transportation cost of liquid carbon dioxide, single product type, and low economic benefit of products is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon dioxide recycling, in particular to a method and device for purifying and liquefying carbon dioxide from industrial tail gas. BACKGROUND

[0002] The tail gas of chemical industry generally contains a large amount of carbon dioxide, recycling and utilizing this part of carbon dioxide can protect the environment and bring certain economic benefits to enterprises. In the prior art, carbon dioxide is generally made into liquid or solid products to facilitate transportation and use.

[0003] The distillation process for producing carbon dioxide by different operating pressures in industry generally adopts high-pressure method, medium-pressure method and low-pressure method. The high-pressure method first compresses the mixed gas to medium pressure for purification, and then pressurizes the carbon dioxide gas to 6MPa to 9MPa to obtain liquid carbon dioxide product at 20℃ to 30℃. The above high-pressure method separates most of the liquefied carbon dioxide from the mixed gas with relatively low energy consumption through multi-stage compression and refrigeration. Then, the above pressurized liquefied carbon dioxide is subjected to high-pressure rectification at room temperature, and the purity of the final carbon dioxide product can reach 99.9%. However, the liquid carbon dioxide obtained by the above high-pressure method has a high pressure, and the carbon dioxide pressure cannot be adjusted in time according to the needs, thereby causing the problems of high transportation cost of liquid carbon dioxide, single product type and low product economic benefit. Moreover, due to the power consumption requirement, low-pressure liquid carbon dioxide needs to be prepared under the premise of reducing energy consumption. SUMMARY

[0004] The present application aims to provide a method and device for purifying and liquefying carbon dioxide from industrial tail gas, which can effectively reduce energy consumption and solve the problems in the prior art that the carbon dioxide pressure cannot be adjusted in time according to the needs in the process of purifying carbon dioxide from industrial tail gas, thereby causing high transportation cost of liquid carbon dioxide, single product type and low product economic benefit. To this end, the present application provides a method for purifying and liquefying carbon dioxide from industrial tail gas, comprising the following steps:

[0005] S1, purifying and liquefying carbon dioxide in industrial tail gas by high-pressure method to obtain high-pressure liquid carbon dioxide product;

[0006] S2, reducing the pressure of the high-pressure liquid carbon dioxide product by a first throttling device to obtain low-pressure and low-temperature liquid carbon dioxide product as product output; and utilizing the cold energy generated in the throttling process of the first throttling device to provide cold energy for the work of purifying and liquefying carbon dioxide in industrial tail gas by the high-pressure method in step S1;

[0007] S3, the high-pressure liquid carbon dioxide product temperature is increased in step S2 without passing through the first throttling device; and, the gaseous carbon dioxide product with increased temperature by heat exchange is introduced into the second compression mechanism for compression, and low-pressure liquid carbon dioxide is obtained by passing through the second throttling device.

[0008] Optionally, in step S3, further comprising:

[0009] The gaseous carbon dioxide contained in the low-pressure liquid carbon dioxide passing through the second throttling device is separated by a second gas-liquid separator and re-introduced into the second compression mechanism for compression.

[0010] Optionally, in step S3, further comprising:

[0011] The liquid carbon dioxide product passing through the second gas-liquid separator enters a pump body, which pressurizes the liquid carbon dioxide product to 2 MPa or other pressure values, thereby obtaining the low-pressure low-temperature liquid carbon dioxide product.

[0012] Optionally, the outlet position of the second compressor of the second compression mechanism is further provided with a fifth heat exchanger for heat dissipation of high-temperature high-pressure gaseous carbon dioxide to ambient temperature high-pressure liquid carbon dioxide.

[0013] Optionally, the high-pressure liquid carbon dioxide product is a 7 MPa, 20℃ liquid carbon dioxide product;

[0014] The low-pressure low-temperature liquid carbon dioxide product is a 2 MPa, -22℃ liquid carbon dioxide product.

[0015] An industrial tail gas purification liquefied carbon dioxide equipment applying the purification liquefied carbon dioxide method, comprising:

[0016] A high-pressure carbon dioxide purification equipment for preparing a high-pressure liquid carbon dioxide product;

[0017] A first throttling device, which is a throttling valve arranged at the outlet position of the high-pressure carbon dioxide purification equipment, for converting the high-pressure liquid carbon dioxide product into a low-pressure low-temperature carbon dioxide product; the first throttling device is in communication with the high-pressure carbon dioxide purification equipment, and provides cold energy for the high-pressure carbon dioxide purification equipment;

[0018] A second compression mechanism, comprising: a second compressor; and, the outlet position of the second compressor is further provided with a fifth heat exchanger for heat dissipation of high-temperature high-pressure gaseous carbon dioxide to ambient temperature high-pressure liquid carbon dioxide;

[0019] A second throttling device arranged at the outlet position of the second compression mechanism for converting ambient temperature high-pressure liquid carbon dioxide into low-pressure liquid carbon dioxide;

[0020] A pump body is arranged at an outlet position of the second throttling device, for pressurizing the low-pressure liquid carbon dioxide to convert it into the low-pressure low-temperature liquid carbon dioxide product.

[0021] The industrial tail gas purification liquefied carbon dioxide device further comprises:

[0022] A second gas-liquid separator is arranged at an outlet position of the second throttling device, and is used for removing gaseous carbon dioxide in the low-pressure liquid carbon dioxide; and the second gas-liquid separator is communicated with an inlet of the second compression mechanism, and the gaseous carbon dioxide is re-input into the second compression mechanism.

[0023] Optionally, the high-pressure method carbon dioxide purification device comprises:

[0024] The first compression mechanism comprises a first compressor which is communicated with the first gas-liquid separator, and is used for increasing the pressure of the raw gas and dehydrating the raw gas;

[0025] A first heat exchanger is used for cooling the dehydrated raw gas at an outlet of the first compressor by using non-condensable gas;

[0026] A rectifying tower is used for rectifying the raw gas, and non-condensable gas is separated from a top of the rectifying tower, and high-purity carbon dioxide product is released from a bottom of the rectifying tower;

[0027] A reboiler is used for re-vaporizing liquid raw gas at the bottom of the rectifying tower;

[0028] A second heat exchanger is used for further cooling the dry raw gas cooled by the reboiler by using a refrigerant;

[0029] A third heat exchanger is used for cooling the non-condensable gas at an outlet of the top of the rectifying tower by using a coolant;

[0030] A fourth heat exchanger is used for cooling the carbon dioxide product at an outlet of the bottom of the rectifying tower by using a coolant.

[0031] Optionally, the first compression mechanism is a three-stage compressor, and the first gas-liquid separator is arranged at an outlet position of each of the three first compressors; and / or,

[0032] The second compression mechanism is a two-stage compressor, and the fifth heat exchanger is arranged at an outlet position of each of the two second compressors.

[0033] The technical scheme of the present application has the following advantages:

[0034] 1. The industrial tail gas purification liquefied carbon dioxide method provided by the present application comprises the following steps:

[0035] S1, purifying and liquefying carbon dioxide in industrial tail gas by high pressure method to obtain high-pressure liquid carbon dioxide product;

[0036] S2, depressurizing the high-pressure liquid carbon dioxide product by the first throttling device to obtain low-pressure and low-temperature liquid carbon dioxide product as product output; and using the cold energy generated in the throttling process of the first throttling device to provide cold energy for the purifying and liquefying carbon dioxide in industrial tail gas in step S1.

[0037] S3, the temperature of the high-pressure liquid carbon dioxide product not passing through the first throttling device in step S2 is increased; and the gaseous carbon dioxide product with increased temperature by heat exchange is introduced into the second compression mechanism for compression and low-pressure liquid carbon dioxide is obtained by the second throttling device.

[0038] In the present application, the cold energy generated in the throttling process of the first throttling device is used to provide cold energy for the purifying and liquefying carbon dioxide in industrial tail gas in step S1. The above method can effectively utilize the cold energy obtained in the throttling process of high-pressure carbon dioxide, thereby improving the energy efficiency of the system and reducing the power consumption per unit product. Moreover, the present application further discloses that the gaseous carbon dioxide product with increased temperature by heat exchange is introduced into the second compression mechanism for compression and low-pressure liquid carbon dioxide is obtained by the second throttling device. Through the above method, the pressure of carbon dioxide can be adjusted to reduce the pressure of liquid carbon dioxide, thereby reducing the transportation cost of liquid carbon dioxide, enriching the product types and improving the economic benefits of the product.

[0039] 2. The method for purifying and liquefying carbon dioxide from industrial tail gas provided by the present application, in step S3, further comprises: separating the gaseous carbon dioxide contained in the low-pressure liquid carbon dioxide passing through the second throttling device by a second gas-liquid separator and re-introducing it into the second compression mechanism for compression.

[0040] In the present application, the gaseous carbon dioxide in the low-pressure liquid carbon dioxide is separated by the above-mentioned second gas-liquid separator and re-introduced into the second compression mechanism for compression. The above-mentioned arrangement can effectively reuse the gaseous carbon dioxide, thereby ensuring the yield of low-pressure liquid carbon dioxide.

[0041] 3. The method for purifying and liquefying carbon dioxide from industrial tail gas provided by the present application, in step S3, further comprises: the liquid carbon dioxide product passing through the second gas-liquid separator enters a pump body, and the pump body pressurizes the liquid carbon dioxide product to 2MPa to obtain the low-pressure and low-temperature liquid carbon dioxide product.

[0042] In the present application, the pump body can effectively pressurize the liquid carbon dioxide product, so as to obtain the required 2MPa liquid carbon dioxide product.

[0043] 4. The method for purifying liquefied carbon dioxide from industrial tail gas provided by the present application, the outlet position of the second compressor of the second compression mechanism is further provided with a fifth heat exchanger for heat dissipation of high-temperature and high-pressure gaseous carbon dioxide to ambient environment to normal-temperature and high-pressure liquid carbon dioxide.

[0044] The fifth heat exchanger can effectively convert the high-temperature and high-pressure gaseous carbon dioxide into normal-temperature and high-pressure liquid carbon dioxide.

[0045] 5. The equipment for purifying liquefied carbon dioxide from industrial tail gas provided by the present application, comprising:

[0046] The high-pressure carbon dioxide purification equipment is used for preparing high-pressure liquid carbon dioxide product;

[0047] The first throttling device is a throttle valve arranged at the outlet position of the high-pressure carbon dioxide purification equipment, and is used for converting the high-pressure liquid carbon dioxide product into low-pressure and low-temperature carbon dioxide product; the first throttling device is in communication with the high-pressure carbon dioxide purification equipment, and provides cold energy for the high-pressure carbon dioxide purification equipment;

[0048] The second compression mechanism comprises a second compressor, and the outlet position of the second compressor is further provided with a fifth heat exchanger for heat dissipation of high-temperature and high-pressure gaseous carbon dioxide to ambient environment to normal-temperature and high-pressure liquid carbon dioxide;

[0049] The second throttling device is arranged at the outlet position of the second compression mechanism, and is used for converting the normal-temperature and high-pressure liquid carbon dioxide into low-pressure liquid carbon dioxide;

[0050] The pump body is arranged at the outlet position of the second throttling device, and is used for pressurizing the low-pressure liquid carbon dioxide, so as to convert it into the low-pressure and low-temperature liquid carbon dioxide product.

[0051] In the present application, the high-pressure carbon dioxide purification equipment, the first throttling device, the second compression mechanism, the second throttling device and the pump body are cooperatively connected, so that different types of liquid carbon dioxide products can be effectively obtained.

[0052] 6. The equipment for purifying liquefied carbon dioxide from industrial tail gas provided by the present application, the high-pressure carbon dioxide purification equipment comprises:

[0053] The first compression mechanism comprises a first compressor, which is connected with the first gas-liquid separator, for increasing the pressure of the raw gas and dehydrating the raw gas;

[0054] The first heat exchanger cools the dehydrated raw gas at the outlet of the first compressor by using the non-condensed gas;

[0055] The rectification tower rectifies the raw gas, the non-condensed gas is separated from the top of the rectification tower, and the high-purity carbon dioxide product is released from the bottom of the tower;

[0056] The reboiler vaporizes the liquid raw gas at the bottom of the rectification tower again;

[0057] The second heat exchanger further cools the dry raw gas cooled by the reboiler by using the refrigerant;

[0058] The third heat exchanger cools the non-condensed gas at the top outlet of the rectification tower by using the coolant;

[0059] The fourth heat exchanger cools the carbon dioxide product at the bottom outlet of the rectification tower by using the coolant.

[0060] In the present application, the high-pressure liquid carbon dioxide product can be effectively prepared by the above-mentioned high-pressure carbon dioxide purification equipment, thereby preparing for subsequent pressure reduction of the high-pressure liquid carbon dioxide product.

[0061] 7. The industrial tail gas purification liquefied carbon dioxide equipment provided by the present application, wherein the first compression mechanism is a three-stage compressor, the outlet positions of the three first compressors are provided with the first gas-liquid separator; the second compression mechanism is a two-stage compressor, and the outlet positions of the two second compressors are provided with the fifth heat exchanger.

[0062] In the present application, the working efficiency of the compression mechanism can be effectively improved by setting the first compression mechanism and the second compression mechanism as multi-stage compressors. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0064] Figure 1 In Example 1 provided by the present application, the structure diagram of the industrial tail gas purification liquefied carbon dioxide equipment using throttling process to generate cold energy.

[0065] Explanation of reference signs:

[0066] 1 - first throttling device; 2 - second throttling device; 3 - second gas-liquid separator; 4 - pump body; 5 - second compressor; 6 - fifth heat exchanger; 7 - first compressor; 8 - first gas-liquid separator; 9 - first heat exchanger; 10 - rectifying column; 11 - reboiler; 12 - second heat exchanger; 13 - third heat exchanger; 14 - fourth heat exchanger. DETAILED DESCRIPTION

[0067] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0068] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0069] Embodiment 1

[0070] An industrial tail gas purification liquefied carbon dioxide method is described, as shown in the figure, comprising the following steps: Figure 1

[0071] S1, purifying and liquefying carbon dioxide in industrial tail gas by high pressure method to obtain high pressure liquid carbon dioxide product; the high pressure liquid carbon dioxide product is a 7 MPa, 20℃ liquid carbon dioxide product;

[0072] S2, depressurizing the high pressure liquid carbon dioxide product by the first throttling device 1 to obtain a low pressure and low temperature liquid carbon dioxide product as a product output; and using the cold energy generated by the first throttling device 1 during throttling to provide cold energy for the high pressure method for purifying and liquefying carbon dioxide in industrial tail gas in step S1;

[0073] S3, the high pressure liquid carbon dioxide product that does not pass through the first throtting device 1 in step S2 is output as a product; and the gaseous carbon dioxide product whose temperature is raised by heat exchange is introduced into the second compressor to be compressed, and low pressure liquid carbon dioxide is obtained by the second throttling device 2; the low pressure liquid carbon dioxide enters the pump body 4, and the pump body 4 pressurizes the liquid carbon dioxide product to 2 MPa to obtain the low pressure and low temperature liquid carbon dioxide product; the low pressure and low temperature liquid carbon dioxide product is a 2 MPa, -22℃ liquid carbon dioxide product.

[0074] ​And, the gaseous carbon dioxide contained in the low-pressure liquid carbon dioxide passing through the second throttling device 2 is separated by a second gas-liquid separator 3 and is re-introduced into the second compression mechanism for compression.

[0075] In the step S3, in order to convert the high-temperature, high-pressure gaseous carbon dioxide into normal-temperature, high-pressure liquid carbon dioxide, a fifth heat exchanger 6 for radiating the high-temperature, high-pressure gaseous carbon dioxide to the normal-temperature, high-pressure liquid carbon dioxide is arranged at the outlet position of the second compressor 5 of the second compression mechanism in the present embodiment. The second compression mechanism is a two-stage compressor, and the fifth heat exchanger 6 is arranged at the outlet position of each of the two second compressors 5.

[0076] Of course, the utilization mode of the gaseous carbon dioxide contained in the low-pressure liquid carbon dioxide in the step S3 is not limited in the present embodiment, and in other embodiments, the gaseous carbon dioxide is not re-introduced into the second compression mechanism for compression, but is stored in a storage tank for other needs.

[0077] Of course, whether the liquid carbon dioxide product passing through the second gas-liquid separator 3 enters the pump body 4 and how much pressure is added is not limited in the present embodiment, and in other embodiments, the liquid carbon dioxide product passing through the second gas-liquid separator 3 is directly output without passing through the pump body 4. Or, the liquid carbon dioxide product passing through the second gas-liquid separator 3 is pressurized to other required pressure values by the pump body 4.

[0078] Of course, the number of stages of the compressors of the first compression mechanism and the second compression mechanism is not limited in the present embodiment, and in other embodiments, the first compression mechanism and the second compression mechanism can also include other numbers of compressors.

[0079] An industrial tail gas purification liquefied carbon dioxide equipment, as shown in Figure 1 includes:

[0080] A high-pressure carbon dioxide purification equipment for preparing a high-pressure liquid carbon dioxide product;

[0081] A first throttling device 1, which is a throttle valve arranged at the outlet position of the high-pressure carbon dioxide purification equipment, is used to convert the high-pressure liquid carbon dioxide product into a low-pressure low-temperature carbon dioxide product; the first throttling device 1 is in communication with the high-pressure carbon dioxide purification equipment to provide cold energy for the high-pressure carbon dioxide purification equipment;

[0082] A second compression mechanism, which includes a second compressor 5, and a fifth heat exchanger 6 arranged at the outlet position of the second compressor 5 and used to radiate the high-temperature, high-pressure gaseous carbon dioxide to the normal-temperature, high-pressure liquid carbon dioxide;

[0083] A second throttling device 2 is arranged at the outlet of the second compression mechanism, and is used to convert the high-pressure liquid carbon dioxide into low-pressure liquid carbon dioxide;

[0084] A second gas-liquid separator 3 is arranged at the outlet of the second throttling device 2, and is used to remove the gaseous carbon dioxide in the low-pressure liquid carbon dioxide; and the second gas-liquid separator 3 is connected to the inlet of the second compression mechanism, and the gaseous carbon dioxide is re-input into the second compression mechanism;

[0085] A pump body 4 is arranged at the outlet of the second throttling device 2, and is used to pressurize the low-pressure liquid carbon dioxide, so as to convert it into the low-pressure low-temperature liquid carbon dioxide product.

[0086] In addition, in order to stably and reliably produce the high-pressure liquid carbon dioxide product, a high-pressure carbon dioxide purification device is further included in the embodiment, as shown in the figure, the device includes: Figure 1

[0087] A first compression mechanism includes a first compressor 7 connected to a first gas-liquid separator 8, and is used to increase the pressure of the raw gas and to dehydrate the raw gas; the first compression mechanism is a three-stage compressor, and the outlet of each of the three first compressors 7 is provided with the first gas-liquid separator 8;

[0088] A first heat exchanger 9 is used to cool the dehydrated raw gas at the outlet of the first compressor 7 by using non-condensable gas;

[0089] A rectifying column 10 is used to rectify the raw gas, and the non-condensable gas is separated from the top of the rectifying column 10, and the high-purity carbon dioxide product is released from the bottom of the rectifying column 10;

[0090] A reboiler 11 is used to vaporize the liquid raw gas at the bottom of the rectifying column 10 again;

[0091] A second heat exchanger 12 is used to further cool the dry raw gas cooled by the reboiler 11 by using a refrigerant;

[0092] A third heat exchanger 13 is used to cool the non-condensable gas at the top outlet of the rectifying column 10 by using a coolant;

[0093] A fourth heat exchanger 14 is used to cool the carbon dioxide product at the bottom outlet of the rectifying column 10 by using a coolant.

[0094] ​Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and can not be enumerated. The obvious changes or variations derived from the above description are still within the protection scope of the present application.

Claims

1. A method for purifying and liquefying carbon dioxide from industrial waste gas, characterized in that, Includes the following steps: S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product. S2, the high-pressure liquid carbon dioxide product is depressurized by the first throttling device (1) to obtain a low-pressure, low-temperature liquid carbon dioxide product, which is then output as a product; and the cold energy generated by the first throttling device (1) during the throttling process is used to provide cold energy for the purification and liquefaction of carbon dioxide in the industrial tail gas by the high-pressure method in step S1. Specifically, the first throttling device (1) cools the dry raw gas, the non-condensable gas at the top outlet of the distillation column, and the high-pressure liquid carbon dioxide product at the bottom outlet of the distillation column during the purification and liquefaction of carbon dioxide in the industrial tail gas. S3, In step S2, the low-pressure, low-temperature carbon dioxide product obtained through the first throttling device (1) is divided into four parts. One part is output, and the other three parts are heat-exchanged through the second to fourth heat exchangers in the purification and liquefaction process of carbon dioxide in industrial tail gas. The second heat exchanger is used to cool the dry raw gas, the third heat exchanger is used to cool the non-condensable gas, and the fourth heat exchanger is used to cool the high-pressure liquid carbon dioxide product. After the temperature of the low-pressure, low-temperature carbon dioxide product is raised by the heat exchange, it is passed into the second compression mechanism for compression, and low-pressure liquid carbon dioxide is obtained through the second throttling device (2).

2. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 1, characterized in that, Step S3 also includes: The gaseous carbon dioxide contained in the low-pressure liquid carbon dioxide passing through the second throttling device (2) is separated by the second gas-liquid separator (3) and then reintroduced into the second compression mechanism for compression.

3. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 2, characterized in that, Step S3 also includes: The liquid carbon dioxide product passing through the second gas-liquid separator (3) enters the pump body (4), and the pump body (4) pressurizes the liquid carbon dioxide product to 2MPa, thereby obtaining the low-pressure, low-temperature liquid carbon dioxide product.

4. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 2, characterized in that, The outlet of the second compressor (5) of the second compression mechanism is also provided with a fifth heat exchanger (6) for dissipating heat from high temperature and high pressure gaseous carbon dioxide to room temperature and high pressure liquid carbon dioxide.

5. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 1, characterized in that, The high-pressure liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 7 MPa and a temperature of 20°C. The low-pressure, low-temperature liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 2MPa and a temperature of -22℃.

6. An industrial tail gas purification and liquefaction equipment for carbon dioxide purification using the method for purifying and liquefying carbon dioxide according to any one of claims 1 to 5, characterized in that, include: High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products; The first throttling device (1) is a throttling valve installed at the outlet of the high-pressure carbon dioxide purification equipment, used to convert the high-pressure liquid carbon dioxide product into a low-pressure, low-temperature carbon dioxide product; the first throttling device (1) is connected to the high-pressure carbon dioxide purification equipment to provide cooling energy to the high-pressure carbon dioxide purification equipment. The second compression mechanism includes: a second compressor (5); and the outlet of the second compressor (5) is also provided with a fifth heat exchanger (6) for dissipating heat from high temperature and high pressure gaseous carbon dioxide to room temperature and high pressure liquid carbon dioxide. The second throttling device (2) is installed at the outlet of the second compression mechanism and is used to convert room temperature, high pressure liquid carbon dioxide into low pressure liquid carbon dioxide. The pump body (4) is located at the outlet of the second throttling device (2) and is used to pressurize the low-pressure liquid carbon dioxide and convert it into the low-pressure, low-temperature liquid carbon dioxide product.

7. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 6, characterized in that, Also includes: The second gas-liquid separator (3) is located at the outlet of the second throttling device (2). The second gas-liquid separator (3) is used to remove gaseous carbon dioxide from the low-pressure liquid carbon dioxide. The second gas-liquid separator (3) is connected to the inlet of the second compression mechanism to reintroduce the gaseous carbon dioxide into the second compression mechanism.

8. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 6, characterized in that, High-pressure carbon dioxide purification equipment includes: The first compression mechanism includes: a first compressor (7), which is connected to a first gas-liquid separator (8) for increasing the pressure of the raw gas and dehydrating the raw gas; The first heat exchanger (9) uses non-condensable gas to cool the dehydrated raw gas at the outlet of the first compressor (7); The distillation column (10) distills the raw gas, and the non-condensable gas is separated from the top of the distillation column (10), while the high-purity carbon dioxide product is released from the bottom of the column. The reboiler (11) vaporizes the liquid raw gas at the bottom of the distillation column (10) once again; In the second heat exchanger (12), the dry raw gas cooled by the reboiler (11) is further cooled by the refrigerant. The third heat exchanger (13) cools the non-condensable gas at the top outlet of the distillation column (10) with a coolant; The fourth heat exchanger (14) cools the carbon dioxide product at the bottom outlet of the distillation column (10) with a coolant.

9. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 8, characterized in that, The first compression mechanism is a three-stage compressor, and the outlet positions of the three first compressors (7) are all equipped with the first gas-liquid separator (8); and / or, The second compression mechanism is a two-stage compressor, and the fifth heat exchanger (6) is provided at the outlet position of both second compressors (5).

Images