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

Abstract

The application discloses a method and device for purifying and liquefying carbon dioxide in industrial tail gas, which can be applied to compressed air energy storage and other fields. The method comprises the following steps: S1, purifying and liquefying carbon dioxide in industrial tail gas to obtain high-pressure liquid carbon dioxide products; S2, a high-energy-consumption preparation method: reducing the pressure of the high-pressure liquid carbon dioxide products through a throttling device, and reducing the temperature of the carbon dioxide products passing through the throttling device through a refrigeration device to obtain low-pressure and low-temperature liquid carbon dioxide products; or a low-energy-consumption preparation method: reducing the pressure of the high-pressure liquid carbon dioxide products through an expansion mechanism, and reducing the temperature of the carbon dioxide products passing through the expansion mechanism through a refrigeration device to obtain low-pressure and low-temperature liquid carbon dioxide products. Through the above structure, the problems of high transportation cost of liquid carbon dioxide, single product type and low economic benefit of products in the process of purifying carbon dioxide in industrial tail gas in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide recovery and utilization technology, specifically to a method and apparatus for purifying and liquefying carbon dioxide from industrial exhaust gas. Background Technology

[0002] Chemical industry exhaust gases typically contain large amounts of carbon dioxide. Recycling and utilizing this carbon dioxide can protect the environment and bring economic benefits to enterprises. Currently, carbon dioxide is generally processed into liquid or solid products for easier transportation and use.

[0003] Industrially, the distillation process for producing carbon dioxide at different operating pressures generally employs high-pressure, medium-pressure, and low-pressure methods. The high-pressure method first purifies the mixed gas by compressing it to medium pressure, then pressurizes the carbon dioxide gas to 6-9 MPa, obtaining liquid carbon dioxide at 20-30°C. This high-pressure method uses multi-stage compression and refrigeration to separate most of the liquefied carbon dioxide from the relatively low-energy-consumption mixed gas. Then, the pressurized liquefied carbon dioxide is subjected to high-pressure distillation at room temperature, ultimately achieving a purity of 99.9%. However, the high pressure of the liquid carbon dioxide produced by this method makes it difficult to adjust the pressure as needed, leading to high transportation costs, limited product variety, and low economic efficiency. Summary of the Invention

[0004] This invention aims to provide a method and apparatus for purifying and liquefying carbon dioxide from industrial waste gas, thereby solving the problems in existing technologies where the carbon dioxide pressure cannot be adjusted in a timely manner as needed during the purification process, leading to high transportation costs, limited product variety, and low economic benefits for liquid carbon dioxide. To this end, this invention provides a method for purifying and liquefying carbon dioxide from industrial waste gas, comprising the following steps:

[0005] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0006] S2, High-energy-consumption preparation method: The high-pressure liquid carbon dioxide product is depressurized using a throttling device, and the carbon dioxide product passing through the throttling device is cooled using a refrigeration device, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product; or,

[0007] Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism, and the carbon dioxide product passing through the expansion mechanism is cooled by a refrigeration device, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product.

[0008] Optionally, in step S2, the low-energy preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method in a heat storage tank; and storing the high-pressure liquid carbon dioxide product obtained in step S1 in a high-pressure storage tank; and / or,

[0009] In step S1, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism.

[0010] Optionally, the thermal storage tank and / or the high-pressure storage tank store energy during off-peak electricity prices and expand to perform work during peak electricity prices through the expansion mechanism.

[0011] Optionally, 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.

[0012] 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℃.

[0013] An industrial tail gas purification and liquefaction carbon dioxide equipment using a method for purifying and liquefying carbon dioxide includes:

[0014] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0015] The throttling device 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.

[0016] Refrigeration equipment used for cooling low-pressure carbon dioxide products.

[0017] Optionally, the refrigeration device includes:

[0018] The first heat exchanger is connected to the outlet of the throttling device and is used to convert the low-pressure, low-temperature liquid carbon dioxide product of the gas-liquid two-phase system into a liquid low-pressure, low-temperature liquid carbon dioxide product.

[0019] A refrigeration compressor is connected to the refrigerant outlet of the first heat exchanger and is used to compress low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant.

[0020] The second heat exchanger is connected to the outlet of the refrigeration compressor and is used to dissipate heat from the high-temperature, high-pressure gaseous refrigerant to the environment so that it becomes a high-pressure, room-temperature gaseous refrigerant.

[0021] The first throttling valve is connected to the outlet of the second heat exchanger and the refrigerant inlet of the first heat exchanger, respectively, to throttle the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant.

[0022] Optionally, 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.

[0023] The low-pressure, low-temperature carbon dioxide product is a gas-liquid two-phase carbon dioxide product at 2MPa and -19℃.

[0024] The liquid low-pressure, low-temperature liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 2 MPa and a temperature of -22°C.

[0025] An industrial tail gas purification and liquefaction carbon dioxide equipment using a method for purifying and liquefying carbon dioxide includes:

[0026] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0027] An expansion mechanism includes: an expander; the expander converts the high-pressure liquid carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product;

[0028] Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products.

[0029] Optionally, the expansion mechanism includes at least two of the expanders; and / or,

[0030] 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 2 MPa and a temperature of -22°C.

[0031] Optional high-pressure carbon dioxide purification equipment includes:

[0032] A purification compressor, wherein there are at least two purification compressors, the purification compressors being connected to a gas-liquid separator, used to increase the pressure of the raw gas and dehydrate the raw gas;

[0033] An intercooler is installed at the outlet of the purification compressor to exchange heat between the coolant and the high-temperature raw gas, thereby raising the temperature of the coolant.

[0034] The first purification heat exchanger uses non-condensable steam to cool the dehydrated raw gas at the outlet of the purification compressor.

[0035] A distillation column is used to distill the raw gas. Non-condensable gases are separated from the top of the column, and high-purity carbon dioxide products are released from the bottom.

[0036] The reboiler re-vaporizes the liquid raw gas at the bottom of the distillation column.

[0037] In the second purification heat exchanger, the dried raw gas cooled by the reboiler is further cooled by the refrigerant.

[0038] The third purification heat exchanger cools the non-condensable vapor at the top outlet of the distillation column using a coolant.

[0039] The fourth purification heat exchanger cools the carbon dioxide product at the bottom outlet of the distillation column using a coolant.

[0040] A refrigeration compressor compresses low-pressure gaseous refrigerant to high pressure;

[0041] The fifth purification heat exchanger is connected to the refrigeration compressor and dissipates heat from the high-temperature, high-pressure gaseous refrigerant to the environment, turning it into a high-pressure, room-temperature gaseous refrigerant.

[0042] The second throttling valve is connected to the fifth purification heat exchanger, which converts the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant through throttling.

[0043] Optional industrial exhaust gas purification and liquefaction carbon dioxide equipment also includes:

[0044] A heat storage tank, connected to the intercooler, stores the heat from the coolant in the intercooler within the heat storage tank; the heat storage tank functions as an expander via a reheater to heat the high-pressure carbon dioxide product entering the expander; and / or,

[0045] The high-pressure storage tank is connected to the outlet of the fourth purification heat exchanger and is used to store the high-pressure liquid carbon dioxide product; and the high-pressure storage tank is connected to the expansion mechanism and provides power to the expansion mechanism through heat energy.

[0046] Optionally, the heat storage tank is a hot water storage tank; the reheater is also connected to a cold water tank, and the water after releasing heat is introduced into the intercooler.

[0047] Optionally, a drive pump is also provided at the inlet of the high-pressure storage tank; the drive pump pressurizes the high-pressure liquid carbon dioxide product to a higher pressure and heats it to a supercritical state using the heat of compression, so as to facilitate the work done by the heat of compression.

[0048] Optionally, the drive pump pressurizes the high-pressure liquid carbon dioxide product to 30 MPa;

[0049] The expansion mechanism is a four-stage expander.

[0050] Optionally, the expansion mechanism is a two-stage expander, and the reheater is provided at the inlet position of both expanders.

[0051] The technical solution of this invention has the following advantages:

[0052] 1. The method for purifying and liquefying carbon dioxide from industrial exhaust gas provided by the present invention includes the following steps:

[0053] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0054] S2, High-energy-consumption preparation method: The high-pressure liquid carbon dioxide product is depressurized using a throttling device, and the carbon dioxide product passing through the throttling device is cooled using a refrigeration device, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product; or,

[0055] Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism and cooled by a refrigeration device to obtain a low-pressure, low-temperature liquid carbon dioxide product; in step S1, the heat of compression generated by the compression device in the high-pressure method is recovered and used to heat the high-pressure carbon dioxide product entering the expansion mechanism to make it supercritical carbon dioxide, and the heat of compression is further recovered.

[0056] In this invention, carbon dioxide in industrial exhaust gas is first purified and liquefied using a high-pressure method to obtain a high-pressure liquid carbon dioxide product. Then, the high-pressure liquid carbon dioxide product is depressurized using a throttling device, and the carbon dioxide product after passing through the throttling device is cooled using a refrigeration device, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product. Alternatively, the high-pressure liquid / supercritical carbon dioxide product is depressurized using an expansion mechanism, and the expanded carbon dioxide product is cooled, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product. The aforementioned throttling device or expansion mechanism can produce a low-pressure, low-temperature liquid carbon dioxide product, thus solving the problem of high pressure in liquid carbon dioxide produced by the high-pressure method. This further solves the problems of high transportation costs, limited product variety, and low economic benefits associated with liquid carbon dioxide.

[0057] 2. The method for purifying and liquefying carbon dioxide from industrial tail gas provided by the present invention, in step S2, the low-energy-consumption preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method through a heat storage tank; and storing the high-pressure liquid carbon dioxide product obtained in step S1 through a high-pressure storage tank; and / or,

[0058] In step S1, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism.

[0059] In this invention, energy can be stored during off-peak electricity prices using the aforementioned thermal storage tank and high-pressure storage tank. During peak electricity prices, work is done through the expansion of carbon dioxide at 7 MPa, and the thermal energy within the storage tank is utilized, thereby reducing the need to purchase electricity from the grid and further improving economic efficiency.

[0060] Furthermore, in this invention, the heat of compression generated during the operation of the compression equipment in the high-pressure method can be recovered; this heat of compression can be used to heat the high-pressure carbon dioxide product entering the expansion mechanism, thereby further improving energy utilization efficiency.

[0061] 3. The industrial exhaust gas purification and liquefaction carbon dioxide equipment provided by the present invention includes: a high-pressure carbon dioxide purification device for preparing high-pressure liquid carbon dioxide product; a throttling device, which is a throttling valve installed at the outlet of the high-pressure carbon dioxide purification device for converting the high-pressure liquid carbon dioxide product into a low-pressure, low-temperature carbon dioxide product; and a refrigeration device for refrigerating the low-pressure carbon dioxide product.

[0062] In this invention, the aforementioned throttling valve can effectively convert high-pressure liquid carbon dioxide into low-pressure, low-temperature carbon dioxide, thereby obtaining low-pressure, low-temperature liquid carbon dioxide. This solves the problems of high transportation costs, limited product variety, and low economic benefits associated with liquid carbon dioxide.

[0063] 4. The industrial exhaust gas purification and liquefaction carbon dioxide equipment provided by the present invention, wherein the refrigeration equipment includes:

[0064] The first heat exchanger is connected to the outlet of the throttling device and is used to convert the low-pressure, low-temperature gas-liquid two-phase carbon dioxide product into a low-pressure, low-temperature liquid carbon dioxide product.

[0065] A refrigeration compressor is connected to the refrigerant outlet of the first heat exchanger and is used to compress low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant.

[0066] The second heat exchanger is connected to the outlet of the refrigeration compressor and is used to dissipate heat from the high-temperature, high-pressure gaseous refrigerant to the environment so that it becomes a high-pressure, room-temperature gaseous refrigerant.

[0067] The first throttling valve is connected to the outlet of the second heat exchanger and the refrigerant inlet of the first heat exchanger, respectively, to throttle the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant.

[0068] In this invention, the above-mentioned refrigeration equipment can effectively obtain liquid carbon dioxide products at 2MPa and -22℃.

[0069] 5. The industrial tail gas purification and liquefaction carbon dioxide equipment provided by the present invention includes:

[0070] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0071] An expansion mechanism includes: an expander; the expander converts the high-pressure liquid carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product;

[0072] Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products.

[0073] In this invention, the aforementioned expansion mechanism can effectively produce low-pressure, low-temperature liquid carbon dioxide, thereby solving the problem of high pressure in liquid carbon dioxide produced by high-pressure methods. This further addresses the issues of high transportation costs, limited product variety, and low economic efficiency associated with liquid carbon dioxide.

[0074] 6. The industrial tail gas purification and liquefaction carbon dioxide equipment provided by the present invention, the high-pressure carbon dioxide purification equipment includes:

[0075] A purification compressor, wherein there are at least two purification compressors, the purification compressors being connected to a gas-liquid separator, used to increase the pressure of the raw gas and dehydrate the raw gas;

[0076] An intercooler is installed at the outlet of the purification compressor to exchange heat between the coolant and the high-temperature raw gas, thereby raising the temperature of the coolant.

[0077] The first purification heat exchanger uses non-condensable steam to cool the dehydrated raw gas at the outlet of the purification compressor.

[0078] A distillation column is used to distill the raw gas. Non-condensable gases are separated from the top of the column, and high-purity carbon dioxide products are released from the bottom.

[0079] The reboiler re-vaporizes the liquid raw gas at the bottom of the distillation column.

[0080] In the second purification heat exchanger, the dried raw gas cooled by the reboiler is further cooled by the refrigerant.

[0081] The third purification heat exchanger cools the non-condensable vapor at the top outlet of the distillation column using a coolant.

[0082] The fourth purification heat exchanger cools the carbon dioxide product at the bottom outlet of the distillation column using a coolant.

[0083] A refrigeration compressor compresses low-pressure gaseous refrigerant to high pressure;

[0084] The fifth purification heat exchanger is connected to the refrigeration compressor and dissipates heat from the high-temperature, high-pressure gaseous refrigerant to the environment, turning it into a high-pressure, room-temperature gaseous refrigerant.

[0085] The second throttling valve is connected to the fifth purification heat exchanger, which converts the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant through throttling.

[0086] In this invention, high-pressure liquid carbon dioxide products can be stably and reliably produced using the above-mentioned high-pressure carbon dioxide purification equipment.

[0087] 7. The industrial tail gas purification and liquefaction carbon dioxide equipment provided by the present invention further includes:

[0088] A heat storage tank, connected to the intercooler, stores the heat from the coolant in the intercooler within the heat storage tank; the heat storage tank functions as an expander via a reheater to heat the high-pressure carbon dioxide product entering the expander; and / or,

[0089] The high-pressure storage tank is connected to the outlet of the fourth purification heat exchanger and is used to store the high-pressure liquid carbon dioxide product; and the high-pressure storage tank is connected to the expansion mechanism and provides power to the expansion mechanism through heat energy.

[0090] In this invention, the heat from the coolant in the intercooler can be stored inside the aforementioned heat storage tank, thereby utilizing the heat of the high-temperature raw gas. Furthermore, in this invention, the aforementioned high-pressure storage tank can effectively store high-pressure liquid carbon dioxide products, allowing them to expand and perform work during peak electricity prices, thereby reducing electricity consumption during peak periods.

[0091] 8. The industrial exhaust gas purification and liquefaction carbon dioxide equipment provided by the present invention, wherein the heat storage tank is a hot water storage tank; the reheater is also connected to a cold water tank, and the water after releasing heat is introduced into the intercooler.

[0092] In this invention, the heat storage tank is a hot water storage tank. By combining the hot water storage tank with the cold water tank, the heat of the coolant in the intercooler can be recovered and utilized.

[0093] 9. The industrial tail gas purification and liquefaction carbon dioxide equipment provided by the present invention further includes a drive pump at the inlet of the high-pressure storage tank; the drive pump pressurizes the high-pressure liquid carbon dioxide product to a higher pressure, thereby heating the heat of compression to a supercritical state to facilitate the work done by the heat of compression.

[0094] In this invention, the aforementioned drive pump can pressurize the high-pressure liquid carbon dioxide product to an even higher pressure, heating it to a supercritical state using the heat of compression. The pressurized high-pressure carbon dioxide product is then passed into the expansion mechanism to further utilize the heat of compression and perform more work. Attached Figure Description

[0095] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0096] Figure 1 A schematic diagram of the structure of an industrial tail gas purification and liquefaction carbon dioxide equipment with a throttle valve in Embodiment 1 provided by the present invention;

[0097] Figure 2 A schematic diagram of the structure of an industrial tail gas purification and liquefaction carbon dioxide equipment with an expander, provided in Embodiment 2 of the present invention;

[0098] Figure 3 A schematic diagram of an industrial tail gas purification and liquefaction carbon dioxide equipment with a drive pump to pressurize liquid carbon dioxide is provided in Embodiment 3 of the present invention.

[0099] Figure 4 A schematic diagram of the structure of an industrial tail gas purification and liquefaction carbon dioxide equipment with a two-stage expander and both using compression heat heating, provided in Embodiment 4 of the present invention.

[0100] Figure 5 This is a schematic diagram of the high-pressure carbon dioxide purification equipment provided by the present invention.

[0101] Explanation of reference numerals in the attached figures:

[0102] 1-Throttling device; 2-Heat storage tank; 3-High-pressure storage tank; 4-First heat exchanger; 5-Refrigeration compressor; 6-Second heat exchanger; 7-First throttling valve; 8-Expander; 9-Purification compressor; 10-Intercooler; 11-First purification heat exchanger; 12-Distillation column; 13-Reboiler; 14-Second purification heat exchanger; 15-Third purification heat exchanger; 16-Fourth purification heat exchanger; 17-Refrigeration compressor; 18-Fifth purification heat exchanger; 19-Second throttling valve; 21-Gas-liquid separator; 22-Reheater; 23-Cold water tank; 24-Drive pump. Detailed Implementation

[0103] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0104] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0105] Example 1

[0106] A method for purifying and liquefying carbon dioxide from industrial exhaust gas is described, such as... Figure 1 As shown, it includes the following steps:

[0107] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0108] S2, High-energy-consumption preparation method: The high-pressure liquid carbon dioxide product is depressurized by the throttling device 1, and the carbon dioxide product passing through the throttling device is cooled by the refrigeration equipment, thereby obtaining a low-pressure and low-temperature liquid carbon dioxide product.

[0109] Among them, the above-mentioned high-pressure liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 7MPa and a temperature of 20℃;

[0110] The low-pressure, low-temperature liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 2 MPa and a temperature of -22°C; or, the low-pressure, low-temperature liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 2 MPa and a temperature of -20°C.

[0111] like Figure 1 As shown, an industrial tail gas purification and liquefaction carbon dioxide equipment using a carbon dioxide purification and liquefaction method includes:

[0112] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0113] 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.

[0114] Refrigeration equipment used for cooling low-pressure carbon dioxide products.

[0115] In this embodiment, as Figure 1 As shown, the refrigeration equipment includes:

[0116] The first heat exchanger 4 is connected to the outlet of the throttling device 1 and is used to convert the low-pressure, low-temperature gas-liquid two-phase carbon dioxide product into a low-pressure, low-temperature liquid carbon dioxide product.

[0117] The refrigeration compressor 5 is connected to the refrigerant outlet of the first heat exchanger 4 and is used to compress the low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant.

[0118] The second heat exchanger 6 is connected to the outlet of the refrigeration compressor 5 and is used to dissipate heat from the high-temperature, high-pressure gaseous refrigerant to the environment so that it becomes a high-pressure, room-temperature gaseous refrigerant.

[0119] The first throttling valve 7 is connected to the outlet of the second heat exchanger 6 and the refrigerant inlet of the first heat exchanger 4, respectively, so as to throttle the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant.

[0120] Example 2

[0121] A method for purifying and liquefying carbon dioxide from industrial waste gas is described, comprising the following steps:

[0122] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0123] In step S1 above, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism;

[0124] S2, Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism, and the carbon dioxide product passing through the expansion mechanism is cooled by a refrigeration device to obtain a low-pressure, low-temperature liquid carbon dioxide product.

[0125] In step S2 above, the low-energy preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method through the heat storage tank 2; and storing the high-pressure liquid carbon dioxide product obtained in step S1 through the high-pressure storage tank 3; the heat storage tank 2 and the high-pressure storage tank 3 store energy during off-peak electricity prices and expand to do work through the expansion mechanism during peak electricity prices.

[0126] Among them, the above-mentioned high-pressure liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 7MPa and a temperature of 20℃;

[0127] 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℃.

[0128] like Figure 2 As shown, the industrial exhaust gas purification and liquefaction carbon dioxide equipment includes:

[0129] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0130] An expansion mechanism includes an expander 8; the expander 8 converts the high-pressure liquid carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product; in this embodiment, the expansion mechanism includes two expanders 8, wherein the expander 8 closest to the high-pressure storage tank 3 is provided with a reheater 22 at its inlet position, and the reheater 22 absorbs the heat from the heat storage tank 2 to power the expander 8.

[0131] Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products.

[0132] Among them, such as Figure 2 The refrigeration equipment shown above includes:

[0133] The first heat exchanger 4 is connected to the outlet of the throttling device 1 and is used to convert the low-pressure, low-temperature gas-liquid two-phase carbon dioxide product into a low-pressure, low-temperature liquid carbon dioxide product.

[0134] The refrigeration compressor 5 is connected to the refrigerant outlet of the first heat exchanger 4 and is used to compress the low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant.

[0135] The second heat exchanger 6 is connected to the outlet of the refrigeration compressor 5 and is used to dissipate heat from the high-temperature, high-pressure gaseous refrigerant to the environment so that it becomes a high-pressure, room-temperature gaseous refrigerant.

[0136] The first throttling valve 7 is connected to the outlet of the second heat exchanger 6 and the refrigerant inlet of the first heat exchanger 4, respectively, so as to throttle the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant.

[0137] 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 gas-liquid two-phase carbon dioxide product is a gas-liquid two-phase carbon dioxide product with a pressure of 2 MPa and a temperature of -19°C; and the liquid low-pressure, low-temperature liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 2 MPa and a temperature of -22°C.

[0138] Among them, such as Figure 5 As shown, the high-pressure carbon dioxide purification equipment includes:

[0139] Purification compressor 9, of which there are at least two, the purification compressor 9 is connected to gas-liquid separator 21, and is used to increase the pressure of raw gas and dehydrate raw gas;

[0140] Intercooler 10 is located at the outlet of the purification compressor 9 and is used to exchange heat between the coolant and the high-temperature raw gas to raise the temperature of the coolant.

[0141] The first purification heat exchanger 11 uses non-condensable steam to cool the dehydrated raw gas at the outlet of the purification compressor 9.

[0142] Distillation column 12 distills the raw gas, and non-condensable gas is separated from the top of the distillation column 12, while high-purity carbon dioxide product is released from the bottom of the column.

[0143] The reboiler 13 causes the liquid raw gas at the bottom of the distillation column 12 to vaporize again;

[0144] In the second purification heat exchanger 14, the dry raw gas cooled by the reboiler 13 is further cooled by the refrigerant.

[0145] The third purification heat exchanger 15 cools the non-condensable vapor at the top outlet of the distillation column 12 using a coolant.

[0146] The fourth purification heat exchanger 16 cools the carbon dioxide product at the bottom outlet of the distillation column 12 with a coolant.

[0147] The refrigeration compressor 17 compresses the low-pressure gaseous refrigerant to a high pressure.

[0148] The fifth purification heat exchanger 18 is connected to the refrigeration compressor 17, which dissipates heat from the high-temperature, high-pressure gaseous refrigerant to the environment, making it a high-pressure, room-temperature gaseous refrigerant.

[0149] The second throttling valve 19 is connected to the fifth purification heat exchanger 18, which converts the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant through throttling.

[0150] In addition, to improve energy efficiency and reduce electricity consumption during peak electricity pricing periods, such as... Figure 2 As shown, the industrial exhaust gas purification and liquefaction carbon dioxide equipment also includes:

[0151] A heat storage tank 2 is connected to the intercooler 10 to store the heat of the coolant in the intercooler 10. The heat storage tank 2 functions as the expander 8 through a reheater 22 to heat the high-pressure carbon dioxide product entering the expander 8. The heat storage tank 2 is a hot water storage tank. The reheater 22 is also connected to a cold water tank 23 to allow water that has released heat to be introduced into the intercooler 10.

[0152] The high-pressure storage tank 3 is connected to the outlet of the fourth purification heat exchanger 16 and is used to store the high-pressure liquid carbon dioxide product; and the high-pressure storage tank 3 is connected to the expansion mechanism and provides energy to the expansion mechanism to do work through heat energy.

[0153] Of course, in this embodiment, there is no specific limitation on whether the industrial exhaust gas purification and liquefaction carbon dioxide equipment has both a heat storage tank 2 and a high-pressure storage tank 3. In other embodiments, the industrial exhaust gas purification and liquefaction carbon dioxide equipment may only include one of the heat storage tank 2 and the high-pressure storage tank 3.

[0154] Example 3

[0155] A method for purifying and liquefying carbon dioxide from industrial waste gas is described, comprising the following steps:

[0156] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0157] In step S1 above, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism;

[0158] S2, Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism, and the carbon dioxide product passing through the expansion mechanism is cooled by a refrigeration device to obtain a low-pressure, low-temperature liquid carbon dioxide product.

[0159] In step S2 above, the low-energy preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method through the heat storage tank 2; and storing the high-pressure liquid carbon dioxide product obtained in step S1 through the high-pressure storage tank 3; the heat storage tank 2 and the high-pressure storage tank 3 store energy during off-peak electricity prices and expand to do work through the expansion mechanism during peak electricity prices.

[0160] Among them, the above-mentioned high-pressure liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 7MPa and a temperature of 20℃;

[0161] 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℃.

[0162] like Figure 3 As shown, the industrial exhaust gas purification and liquefaction carbon dioxide equipment includes:

[0163] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0164] An expansion mechanism includes an expander 8; the expander 8 converts the high-pressure carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product; in this embodiment, the expansion mechanism includes a four-stage expander 8; a reheater 22 is also provided at the inlet of the expander 8, the reheater 22 is for the function of the expander 8, to heat the high-pressure carbon dioxide product entering the expander 8.

[0165] A drive pump 24 is installed at the inlet of the high-pressure storage tank 3; the drive pump 24 pressurizes the high-pressure liquid carbon dioxide product to a higher pressure and heats it to a supercritical state using the heat of compression to facilitate the work done by the heat of compression; the drive pump 24 pressurizes the high-pressure liquid carbon dioxide product to 30MPa or higher pressure;

[0166] Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products.

[0167] Example 4

[0168] A method for purifying and liquefying carbon dioxide from industrial waste gas is described, comprising the following steps:

[0169] S1, purifies and liquefies carbon dioxide in industrial exhaust gas using a high-pressure method to obtain high-pressure liquid carbon dioxide product.

[0170] In step S1 above, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism;

[0171] S2, Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism, and the carbon dioxide product passing through the expansion mechanism is cooled by a refrigeration device to obtain a low-pressure, low-temperature liquid carbon dioxide product.

[0172] In step S2 above, the low-energy preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method through the heat storage tank 2; and storing the high-pressure liquid carbon dioxide product obtained in step S1 through the high-pressure storage tank 3; the heat storage tank 2 and the high-pressure storage tank 3 store energy during off-peak electricity prices and expand to do work through the expansion mechanism during peak electricity prices.

[0173] Among them, the above-mentioned high-pressure liquid carbon dioxide product is a liquid carbon dioxide product with a pressure of 7MPa and a temperature of 20℃;

[0174] 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℃.

[0175] like Figure 4 As shown, the industrial exhaust gas purification and liquefaction carbon dioxide equipment includes:

[0176] High-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products;

[0177] An expansion mechanism includes an expander 8; the expander 8 converts the high-pressure liquid carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product; in this embodiment, the expansion mechanism includes two-stage expanders 8; a reheater 22 is provided at the inlet of each of the two expanders 8, the reheater 22 is the function of the expander 8, to heat the high-pressure carbon dioxide product entering the expander 8.

[0178] A drive pump 24 is installed at the inlet of the high-pressure storage tank 3; the drive pump 24 pressurizes the high-pressure liquid carbon dioxide product to a higher pressure, so that the heat of compression is heated to a supercritical state, so as to facilitate the work done by the heat of compression; the drive pump 24 pressurizes the high-pressure liquid carbon dioxide product to 30MPa or higher pressure;

[0179] Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products.

[0180] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An industrial waste gas purification and liquefaction carbon dioxide equipment, characterized in that, include: A high-pressure carbon dioxide purification device includes: a purification compressor (9), wherein there are at least two purification compressors (9), which are connected to a gas-liquid separator (21) for increasing the pressure of the raw gas and dehydrating the raw gas; an intercooler (10), located at the outlet of the purification compressor (9), for exchanging heat between the coolant and the high-temperature raw gas to raise the temperature of the coolant; a first purification heat exchanger (11), which uses non-condensable vapor to cool the dehydrated raw gas at the outlet of the purification compressor (9); a distillation column (12), which distills the raw gas, and the non-condensable vapor is separated from the top of the distillation column (12), and the high-purity carbon dioxide product is released from the bottom of the column; a reboiler (13), which vaporizes the liquid raw gas at the bottom of the distillation column (12) again; and a second purification heat exchanger (14), which, through the gas-liquid separator (21), cools the raw gas. The dry raw gas cooled by the reboiler (13) is further cooled by the refrigerant; the third purification heat exchanger (15) cools the non-condensable vapor at the top outlet of the distillation column (12) with the coolant; the fourth purification heat exchanger (16) cools the carbon dioxide product at the bottom outlet of the distillation column (12) with the coolant; the refrigeration compressor (17) compresses the low-pressure gaseous refrigerant to high pressure; the fifth purification heat exchanger (18) is connected to the refrigeration compressor (17) and dissipates the high-temperature, high-pressure gaseous refrigerant to the environment, becoming a high-pressure, room-temperature gaseous refrigerant; the second throttle valve (19) is connected to the fifth purification heat exchanger (18) and converts the high-pressure, room-temperature gaseous refrigerant into a low-pressure, low-temperature liquid refrigerant through throttling. The high-pressure carbon dioxide purification equipment is used to prepare high-pressure liquid carbon dioxide products. An expansion mechanism includes: an expander (8); the expander (8) converts the high-pressure liquid carbon dioxide product or supercritical carbon dioxide product into a low-pressure carbon dioxide product; Refrigeration equipment used to cool low-pressure carbon dioxide products and convert them into low-pressure, low-temperature liquid carbon dioxide products; A heat storage tank (2), connected to the intercooler (10), stores the heat of the coolant in the intercooler (10) in the heat storage tank (2); the heat storage tank (2) supplies energy to the expander (8) through a reheater (22) to heat the high-pressure carbon dioxide product entering the expander (8); and / or, The high-pressure storage tank (3) is connected to the outlet of the fourth purification heat exchanger (16) and is used to store the high-pressure liquid carbon dioxide product; and the high-pressure storage tank (3) is connected to the expansion mechanism and provides energy to the expansion mechanism through heat.

2. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 1, characterized in that, The expansion mechanism includes at least two of the expanders (8); and / or, 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 2 MPa and a temperature of -22°C.

3. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 1, characterized in that, The heat storage tank (2) is a hot water storage tank; the reheater (22) is also connected to the cold water tank (23) to pass the water after releasing heat into the intercooler (10).

4. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 1, characterized in that, The high-pressure storage tank (3) is also equipped with a drive pump (24) at its inlet. The drive pump (24) pressurizes the high-pressure liquid carbon dioxide product to a higher pressure, so that the heat of compression is heated to a supercritical state, which is conducive to the heat of compression doing work.

5. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 4, characterized in that, The drive pump (24) pressurizes the high-pressure liquid carbon dioxide product to 30 MPa; The expansion mechanism is a four-stage expander (8).

6. The industrial tail gas purification and liquefaction carbon dioxide equipment according to claim 1, characterized in that, The expansion mechanism is a two-stage expander (8), and the reheater (22) is provided at the inlet of both expanders (8).

7. A method for purifying and liquefying carbon dioxide from industrial waste gas, characterized in that, The method, applied to the industrial tail gas purification and liquefaction carbon dioxide equipment according to any one of claims 1 to 6, comprises 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, Low-energy preparation method: The high-pressure liquid carbon dioxide product is depressurized by an expansion mechanism, and the carbon dioxide product passing through the expansion mechanism is cooled by a refrigeration device, thereby obtaining a low-pressure, low-temperature liquid carbon dioxide product.

8. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 7, characterized in that, In step S2, the low-energy preparation method further includes: storing the heat of compression generated by the compression equipment in the high-pressure method through a heat storage tank (2); and storing the high-pressure liquid carbon dioxide product obtained in step S1 through a high-pressure storage tank (3). In step S1, the heat of compression generated by the compression equipment in the high-pressure method is recovered; the heat of compression is used to heat the high-pressure carbon dioxide product entering the expansion mechanism.

9. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 8, characterized in that, The thermal storage tank (2) and / or the high-pressure storage tank (3) store energy during off-peak electricity prices and expand to do work during peak electricity prices through the expansion mechanism.

10. The method for purifying and liquefying carbon dioxide from industrial tail gas according to claim 7, 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℃.

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