A near-zero energy direct air capture system driven by industrial waste heat

Abstract

This invention provides a near-zero energy direct air capture system driven by industrial waste heat, comprising a heat source, a first steam expander, a carbon dioxide adsorption / desorption unit, and a fan. The heat source supplies first steam, and the first steam expander drives the fan based on the first steam. The fan transports a carbon dioxide-containing fluid to the carbon dioxide adsorption / desorption unit, which performs carbon dioxide adsorption and / or desorption. Preferably, the first steam expander provides heat energy for carbon dioxide desorption in the carbon dioxide adsorption / desorption unit. The system may also include a second steam expander for compressing the captured carbon dioxide using the heat from the first steam. The energy required by the direct air capture system can be provided entirely by industrially abundant low-pressure steam, thus enabling near-zero energy operation.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide gas capture technology, and in particular to a direct air capture system. Background Technology

[0002] Direct air capture (DAC) is a highly efficient negative emission technology that can capture distributed carbon emission sources. However, DAC technology requires approximately 80% thermal energy and about 20% electrical energy for the fan during the adsorption process, resulting in high energy consumption and cost, which limits its large-scale commercialization. In the iron and steel smelting, non-ferrous metal smelting, non-metallic processing, and petrochemical industries, a large amount of waste heat exists in the form of low-pressure steam and cannot be effectively utilized.

[0003] If these low-pressure steams can be used for air intake and carbon dioxide purification, near-zero energy consumption operation of the DAC system can be achieved. Summary of the Invention

[0004] The purpose of this invention is to provide a near-zero energy direct air capture system driven by industrial waste heat. This near-zero energy direct air capture system reduces the energy consumption of the DAC system by delivering low-pressure steam provided by an external heat source to the DAC system to drive a steam expander to provide kinetic energy to the fan and carbon dioxide compressor. Furthermore, the exhaust steam generated by the steam expander provides energy to the steam-water separator, eliminating the need for the steam-water separator to provide additional electrical energy.

[0005] To achieve the objectives of this invention, the following technical solution is adopted:

[0006] In a first aspect, this application provides a near-zero energy direct air capture system driven by industrial waste heat, characterized in that it includes a heat source, a first steam expander, a carbon dioxide adsorption / desorption unit, and a fan. In this embodiment, the heat source is used to supply first steam, the first steam expander is used to drive the fan based on the first steam, and the fan is used to transport a carbon dioxide-containing fluid to the carbon dioxide adsorption / desorption unit;

[0007] The carbon dioxide adsorption / desorption unit is used to perform one or both of the following steps: Step A: adsorbing carbon dioxide in the fluid flowing through the carbon dioxide adsorption / desorption unit to obtain first condensate and fluid after carbon dioxide adsorption; and Step B: desorbing the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit to obtain carbon dioxide rich in water vapor.

[0008] In one embodiment of the first aspect, the near-zero energy direct air capture system driven by industrial waste heat described herein further includes a steam-water separator for separating the exhaust steam generated by the first steam expander into a second steam and a second condensate, wherein the second steam is used to desorb the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit to obtain carbon dioxide rich in water vapor.

[0009] In one embodiment of the first aspect, the near-zero energy direct air capture system driven by industrial waste heat described herein further includes a second steam expander, a carbon dioxide compressor, and optionally a carbon dioxide dehydration unit. In this embodiment, the second steam expander is used to drive the carbon dioxide compressor based on the first steam, the carbon dioxide compressor is used to compress water vapor-rich carbon dioxide from the carbon dioxide adsorption / desorption unit to obtain compressed carbon dioxide, and the carbon dioxide dehydration unit is used to dehydrate the compressed carbon dioxide to obtain dehydrated carbon dioxide and a fourth condensate.

[0010] In one embodiment of the first aspect, the near-zero energy direct air capture system driven by industrial waste heat described herein further includes a steam-water separator, which is also used to separate the exhaust steam generated by the second steam expander into a third steam and a third condensate, wherein the third steam is used to desorb the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit to obtain carbon dioxide rich in water vapor.

[0011] In one embodiment of the first aspect, the steam-water separator is further used to separate the exhaust steam generated by the first steam expander into second steam and second condensate, wherein the second steam is used to desorb the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit to obtain carbon dioxide rich in water vapor.

[0012] In one embodiment of the first aspect, the carbon dioxide-containing fluid is air, the first steam is low-pressure steam, and the pressure value of the first steam is less than or equal to 0.5 MPaG.

[0013] In one embodiment of the first aspect, the carbon dioxide adsorption / desorption unit includes an adsorbent for adsorbing carbon dioxide.

[0014] In one embodiment of the first aspect, the carbon dioxide adsorption / desorption unit includes a reactor in which step A is performed when a carbon dioxide-containing fluid is introduced, and step B is performed when steam is introduced.

[0015] In one embodiment of the first aspect, the carbon dioxide adsorption / desorption unit includes at least a first reactor and a second reactor, the first reactor being used to perform step A and the second reactor being used to perform step B; wherein the first reactor includes an adsorbent for adsorbing carbon dioxide, and the adsorbent after adsorbing carbon dioxide in the first reactor can be transferred to the second reactor.

[0016] In one embodiment of the first aspect, the near-zero energy direct air capture system driven by industrial waste heat includes a heat source, a first steam expander, a carbon dioxide adsorption / desorption unit, a fan, and a steam-water separator. The heat source supplies low-pressure steam; one end of the first steam expander is connected to the heat source; the carbon dioxide adsorption / desorption unit includes an adsorbent for adsorbing carbon dioxide from the air flowing through it and discharging the carbon dioxide-free air; one end of the fan is connected to the first steam expander, and the other end is connected to the carbon dioxide adsorption / desorption unit, for drawing in air and delivering it to the unit; one end of the steam-water separator is connected to the first steam expander, and the other end is connected to the carbon dioxide adsorption / desorption unit, for separating the waste steam generated by the first steam expander into steam and delivering it to the carbon dioxide adsorption / desorption unit to desorb carbon dioxide from the adsorbent, thereby regenerating the adsorbent.

[0017] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a steam main pipe, a first steam expander inlet pipe, and a fan outlet pipe, wherein the first steam expander is connected to the heat source in sequence through the first steam expander inlet pipe and the steam main pipe; the fan includes an air inlet and is connected to the carbon dioxide adsorption / desorption unit through the fan outlet pipe, so that air drawn in from the air inlet is transported to the carbon dioxide adsorption / desorption unit under the action of the first steam expander.

[0018] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a first steam expander outlet pipe, a steam-water separator inlet pipe, and a steam-water separator outlet pipe, wherein the first steam expander is connected to the steam-water separator in sequence through the first steam expander outlet pipe and the steam-water separator inlet pipe to transport the waste steam to the steam-water separator; the steam-water separator is connected to the carbon dioxide adsorption / desorption unit through the steam-water separator outlet pipe.

[0019] According to one embodiment of the present invention, the carbon dioxide adsorption / desorption unit further includes an air outlet and a first condensate outlet to discharge the separated air and condensate respectively.

[0020] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a second steam expander, a carbon dioxide compressor, and a carbon dioxide dehydration unit, wherein the second steam expander is connected to the heat source, one end of the carbon dioxide compressor is connected to the second steam expander, and the other end is connected to the carbon dioxide dehydration unit.

[0021] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a second steam expander inlet pipe and a second steam expander outlet pipe, wherein the second steam expander is connected to the heat source through the second steam expander inlet pipe, and is connected to the steam-water separator in sequence through the second steam expander outlet pipe and the steam-water separator outlet pipe, so as to transport the exhaust steam generated by the second steam expander to the steam-water separator.

[0022] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a carbon dioxide compressor inlet pipe, wherein the carbon dioxide adsorption / desorption unit is connected to the carbon dioxide compressor through the carbon dioxide compressor inlet pipe to pressurize the carbon dioxide containing water vapor input from the carbon dioxide adsorption / desorption unit under the action of the second steam expander.

[0023] According to one embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes: a carbon dioxide compressor outlet pipe, wherein the carbon dioxide compressor is connected to the carbon dioxide dehydration unit through the carbon dioxide compressor outlet pipe to deliver pressurized carbon dioxide to the carbon dioxide dehydration unit for dehydration.

[0024] According to one embodiment of the present invention, the carbon dioxide dehydration unit includes a carbon dioxide outlet and a second condensate outlet to discharge the separated carbon dioxide and condensate respectively.

[0025] According to one embodiment of the present invention, the low-pressure steam of the heat source originates from industrial waste heat, and the pressure value of the low-pressure steam is less than or equal to 0.5 MPaG.

[0026] One embodiment of the present invention has the following advantages or beneficial effects:

[0027] The near-zero energy direct air capture system driven by industrial waste heat of the present invention includes a heat source, a first steam expander, a carbon dioxide adsorption / desorption unit, a fan, a steam-water separator, a second steam expander, a carbon dioxide compressor, and a carbon dioxide dehydration unit. The low-pressure steam from the heat source, with a pressure value less than or equal to 0.5 MPaG, originates from a large amount of waste heat generated in iron and steel smelting, non-ferrous metal smelting, non-metallic processing, and petrochemical industries. The low-pressure steam from the heat source is introduced into the first and second steam expanders, where gas expansion and pressure reduction generate mechanical energy to drive the fan and carbon dioxide compressor. The fan directly draws in air and inputs it into the carbon dioxide adsorption / desorption unit, where the adsorbent adsorbs and stores the carbon dioxide, and the air with the carbon dioxide removed is discharged. The waste steam generated by the first and second steam expanders is supplied to the steam-water separator, where the waste steam is separated and sent to the carbon dioxide adsorption / desorption unit to desorb carbon dioxide from the adsorbent, thus regenerating the adsorbent. The carbon dioxide compressor can pressurize the water-rich carbon dioxide from the carbon dioxide adsorption / desorption unit and send it to the carbon dioxide dehydration unit for dehydration to obtain high-purity carbon dioxide. Attached Figure Description

[0028] The above and other features and advantages of the present invention will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of a near-zero energy direct air capture system driven by industrial waste heat, according to an exemplary embodiment. Figure 1 In the example, air is used as a fluid containing carbon dioxide.

[0030] The reference numerals in the attached figures are explained as follows:

[0031] 1. Heat source; 11. Steam main pipe; 12. Inlet pipe of the first steam expander; 13. Outlet pipe of the blower; 14. Outlet pipe of the first steam expander; 15. Inlet pipe of the steam-water separator; 16. Outlet pipe of the steam-water separator; 17. Inlet pipe of the second steam expander; 18. Outlet pipe of the second steam expander; 19. Inlet pipe of the carbon dioxide compressor; 20. Outlet pipe of the carbon dioxide compressor;

[0032] 2. First steam expander;

[0033] 3. Carbon dioxide adsorption / desorption unit; 31. Gas outlet; 32. First condensate outlet;

[0034] 4. Fan; 41. Air inlet;

[0035] 5. Steam-water separator;

[0036] 6. Second steam expander;

[0037] 7. Carbon dioxide compressor;

[0038] 8. Carbon dioxide dehydration unit; 81. Carbon dioxide outlet; 82. Second condensate outlet. Detailed Implementation

[0039] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0040] The terms “a,” “one,” “the,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended meaning of inclusion and that other elements / components / etc. may exist in addition to the listed elements / components / etc.

[0041] like Figure 1 As shown, Figure 1 A schematic diagram of a near-zero energy consumption direct air capture system driven by industrial waste heat provided by the present invention is shown.

[0042] The near-zero energy direct air capture system driven by industrial waste heat in this embodiment of the invention includes a heat source 1, a first steam expander 2, a carbon dioxide adsorption / desorption unit 3, a fan 4, and a steam-water separator 5. The heat source 1 supplies low-pressure steam. One end of the first steam expander 2 is connected to the heat source 1. The carbon dioxide adsorption / desorption unit 3 includes an adsorbent, used to adsorb carbon dioxide from the air flowing through the unit and discharge the air after removing the carbon dioxide. One end of the fan 4 is connected to the first steam expander 2, and the other end is connected to the carbon dioxide adsorption / desorption unit 3, used to draw in air and deliver it to the unit. One end of the steam-water separator 5 is connected to the first steam expander 2, and the other end is connected to the carbon dioxide adsorption / desorption unit 3, used to separate the waste steam generated by the first steam expander 2 into steam and deliver it to the carbon dioxide adsorption / desorption unit 3 to desorb carbon dioxide from the adsorbent, thereby regenerating the adsorbent.

[0043] In this document, the carbon dioxide adsorption / desorption unit 3 is used to perform one or both of the following steps: Step A: adsorbing carbon dioxide from the fluid flowing through the carbon dioxide adsorption / desorption unit 3 to obtain first condensate and the fluid after carbon dioxide adsorption; and Step B: desorbing the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit 3 to obtain carbon dioxide rich in water vapor. In other words, the carbon dioxide adsorption / desorption unit 3 can perform only the carbon dioxide adsorption step, only the carbon dioxide desorption step, or both the carbon dioxide adsorption and desorption steps simultaneously. The carbon dioxide adsorption step can be implemented using an adsorbent provided in the carbon dioxide adsorption / desorption unit 3.

[0044] In one embodiment, the carbon dioxide adsorption / desorption unit 3 may include only one reactor. When a carbon dioxide-containing fluid is introduced into the reactor, step A, i.e., adsorption of carbon dioxide, is performed in the reactor. When steam is introduced into the reactor, step B, i.e., desorption of carbon dioxide, is performed in the reactor. In another embodiment, the carbon dioxide adsorption / desorption unit 3 includes at least two independent reactors. For example, the carbon dioxide adsorption / desorption unit 3 may include a first reactor and a second reactor, the first reactor being used to perform step A and the second reactor being used to perform step B. In this embodiment, the first reactor includes an adsorbent for adsorbing carbon dioxide, and the adsorbent after adsorption of carbon dioxide in the first reactor can be transferred to the second reactor. It should be noted that the second reactor can also be used to desorb carbon dioxide-adsorbed material from other sources. In this case, those skilled in the art will understand that the fan 4 can be connected to the first reactor to deliver a carbon dioxide-containing fluid, such as air, to the first reactor. After adsorption by the adsorbent in the first reactor, condensate and adsorbed fluid are obtained. The steam-water separator 5 can be connected to the second reactor to deliver the separated steam to the second reactor to regenerate the adsorbent and obtain carbon dioxide rich in water vapor. In a preferred embodiment, water vapor-rich carbon dioxide can be fed to a carbon dioxide compressor 7 for compression to obtain compressed carbon dioxide.

[0045] In this paper, exhaust steam refers to the steam-water mixture discharged from the outlet of the steam expander. Heat source 1 mainly originates from the large amount of waste heat existing in the form of low-pressure steam in iron and steel smelting, non-ferrous metal smelting, non-metallic processing, and petrochemical industries. The first steam expander 2 and the subsequent second steam expander 6 are of the same type of expander. Low-pressure steam from heat source 1 flows into the first steam expander 2 and the subsequent second steam expander 6, respectively, where it expands and depressurizes to generate mechanical energy. The first steam expander 2 provides mechanical energy to the blower 4, which uses this mechanical energy to draw air from the surrounding environment and deliver it to the carbon dioxide adsorption / desorption unit 3. The carbon dioxide adsorption / desorption unit 3 contains an adsorbent capable of adsorbing and storing carbon dioxide from the air. After depressurization, the first steam expander 2 generates exhaust steam, which is then delivered to the steam-water separator 5. The steam-water separator 5 separates the steam from the exhaust steam and delivers it to the carbon dioxide adsorption / desorption unit 3, which, as a heat source, desorbs the carbon dioxide adsorbed in the adsorbent, yielding carbon dioxide rich in water vapor, while simultaneously regenerating the adsorbent.

[0046] In a preferred embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes a steam main pipe 11, a first steam expander inlet pipe 12, and a fan outlet pipe 13. The first steam expander 2 is connected to the heat source 1 in sequence through the first steam expander inlet pipe 12 and the steam main pipe 11. The fan 4 includes an air inlet 41 and is connected to a carbon dioxide adsorption / desorption unit 3 through the fan outlet pipe 13, so that the air drawn in from the air inlet 41 is transported to the carbon dioxide adsorption / desorption unit 3 under the action of the first steam expander 2.

[0047] like Figure 1 As shown, a steam main 11 extends from the heat source 1. The steam main 11 branches into two branches, one of which connects to the inlet pipe 12 of the first steam expander. Preferably, a valve is installed on the inlet pipe 12 of the first steam expander to control its opening and closing. The blower 4 draws air directly from the air inlet 41.

[0048] In a preferred embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes a first steam expander outlet pipe 14, a steam-water separator inlet pipe 15, and a steam-water separator outlet pipe 16. The first steam expander 2 is connected to the steam-water separator 5 in sequence through the first steam expander outlet pipe 14 and the steam-water separator inlet pipe 15 to transport waste steam to the steam-water separator 5. The steam-water separator 5 is connected to the carbon dioxide adsorption / desorption unit 3 through the steam-water separator outlet pipe 16.

[0049] like Figure 1As shown, the inlet pipe 15 of the steam-water separator includes two branches, one of which connects to the outlet pipe 14 of the first steam expander. The first steam expander 2 expands and depressurizes the low-pressure steam input from the heat source 1 to produce exhaust steam, which is then transported to the steam-water separator 5. The steam-water separator 5 can separate the steam from the exhaust steam and transport it to the carbon dioxide adsorption / desorption unit 3.

[0050] In a preferred embodiment of the present invention, the carbon dioxide adsorption / desorption unit 3 further includes an air outlet 31 and a first condensate outlet 32 ​​to discharge the separated air and condensate respectively.

[0051] like Figure 1 As shown, the air after carbon dioxide adsorption is discharged to the outside through the air outlet 31. The condensate generated in the middle flows out to the outside through the first condensate outlet 32.

[0052] In a preferred embodiment of the present invention, the near-zero energy consumption direct air capture system driven by industrial waste heat further includes a second steam expander 6, a carbon dioxide compressor 7, and a carbon dioxide dehydration unit 8, wherein the second steam expander 6 is connected to the heat source 1; one end of the carbon dioxide compressor 7 is connected to the second steam expander 6, and the other end is connected to the carbon dioxide dehydration unit 8.

[0053] like Figure 1 As shown, the second steam expander 6 expands and depressurizes the low-pressure steam input from the heat source 1 to generate mechanical energy, which drives the carbon dioxide compressor 7 to work. The carbon dioxide compressor 7 then pressurizes the water-rich carbon dioxide input into it and delivers it to the carbon dioxide dehydration unit 8.

[0054] In a preferred embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes a second steam expander inlet pipe 17 and a second steam expander outlet pipe 18, wherein the second steam expander 6 is connected to the heat source 1 through the second steam expander inlet pipe 17, and is connected to the steam-water separator 5 in sequence through the second steam expander outlet pipe 18 and the steam-water separator outlet pipe 16, so as to transport the exhaust steam generated by the second steam expander 6 to the steam-water separator 5.

[0055] like Figure 1 As shown, the inlet pipe 17 of the second steam expander is connected to another branch of the main steam pipe (11). Preferably, a valve body is provided on the inlet pipe 17 of the second steam expander for controlling its opening and closing. The exhaust steam generated by the second steam expander 6 is also transported to the steam-water separator 5 through the outlet pipe 18 of the second steam expander.

[0056] In a preferred embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes a carbon dioxide compressor inlet pipe 19, wherein the carbon dioxide adsorption / desorption unit 3 is connected to the carbon dioxide compressor 7 through the carbon dioxide compressor inlet pipe 19, so as to pressurize the carbon dioxide containing water vapor input from the carbon dioxide adsorption / desorption unit 3 under the action of the second steam expander 6.

[0057] like Figure 1 As shown, the carbon dioxide compressor 7 draws in the steam-rich carbon dioxide from the carbon dioxide adsorption / desorption unit 3 through the carbon dioxide compressor inlet pipe 19 and pressurizes it.

[0058] In a preferred embodiment of the present invention, the near-zero energy direct air capture system driven by industrial waste heat further includes a carbon dioxide compressor outlet pipe 20, wherein the carbon dioxide compressor 7 is connected to a carbon dioxide dehydration unit 8 through the carbon dioxide compressor outlet pipe 20 to deliver pressurized carbon dioxide to the carbon dioxide dehydration unit 8 for dehydration. The carbon dioxide dehydration unit 8 includes a carbon dioxide outlet 81 and a second condensate outlet 82 to discharge the separated carbon dioxide and condensate separately.

[0059] like Figure 1 As shown, the steam-rich carbon dioxide is pressurized by the carbon dioxide compressor 7 and then transported to the carbon dioxide dehydration unit 8 through the carbon dioxide compressor outlet pipe 20 for processing. The resulting dehydrated high-purity carbon dioxide is discharged from the carbon dioxide outlet 81.

[0060] In a preferred embodiment of the present invention, the low-pressure steam of heat source 1 is derived from industrial waste heat, and the pressure value of the low-pressure steam is less than or equal to 0.5 MPaG.

[0061] The near-zero energy direct air capture system driven by industrial waste heat of the present invention includes a heat source 1, a first steam expander 2, a carbon dioxide adsorption / desorption unit 3, a fan 4, a steam-water separator 5, a second steam expander 6, a carbon dioxide compressor 7, and a carbon dioxide dehydration unit 8. The low-pressure steam of the heat source 1, with a pressure value less than or equal to 0.5 MPaG, originates from a large amount of waste heat in iron and steel smelting, non-ferrous metal smelting, non-metallic processing, and petrochemical industries. The low-pressure steam from the heat source 1 is introduced into the first steam expander 2 and the second steam expander 6, where gas expansion and pressure reduction generate mechanical energy to drive the fan 4 and the carbon dioxide compressor 7. The fan 4 directly draws in air and inputs it into the carbon dioxide adsorption / desorption unit 3, where the adsorbent adsorbs and stores the carbon dioxide, and the air with the carbon dioxide removed is discharged. The waste steam generated by the first steam expander 2 and the second steam expander 6 is supplied to the steam-water separator 5, where the waste steam is separated and sent to the carbon dioxide adsorption / desorption unit 3 to desorb carbon dioxide from the adsorbent, thus regenerating the adsorbent. The carbon dioxide compressor 7 pressurizes the water vapor-rich carbon dioxide from the carbon dioxide adsorption / desorption unit 3 and sends it to the carbon dioxide dehydration unit 8 for dehydration to obtain high-purity carbon dioxide. The near-zero energy direct air capture system driven by industrial waste heat provides the fan drive energy required for carbon dioxide capture, the carbon dioxide compressor drive energy required for carbon dioxide pressurization, and the heat energy required for carbon dioxide desorption in the adsorbent, all supplied by abundant low-pressure steam in the industry. Therefore, the DAC system can achieve near-zero energy consumption operation.

[0062] In this embodiment of the invention, the term "multiple" refers to two or more, unless otherwise explicitly defined. The terms "install," "connect," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention based on the specific circumstances.

[0063] In the description of the embodiments of the present invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0064] In the description of this specification, the terms "an embodiment," "a preferred embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. For those skilled in the art, the embodiments of the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A direct air capture system driven by industrial waste heat, characterized in that, It includes a heat source (1), a first steam expander (2), a second steam expander (6), a carbon dioxide adsorption / desorption unit (3), a fan (4), a carbon dioxide compressor (7), and a steam-water separator (5); The heat source (1) is used to supply the first steam, which is a low-pressure steam with a pressure value of less than or equal to 0.5 MPaG and originates from industrial waste heat. The first steam expander (2) is used to drive the blower (4) based on the first steam, and the blower (4) is used to transport the carbon dioxide-containing fluid to the carbon dioxide adsorption / desorption unit (3). The second steam expander (6) is used to drive the carbon dioxide compressor (7) based on the first steam; The steam-water separator (5) is used to separate the exhaust steam generated by the first steam expander (2) and the second steam expander (6) into second steam and third steam, respectively. The second steam and third steam are used to desorb the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit (3) to obtain carbon dioxide rich in water vapor. The carbon dioxide adsorption / desorption unit (3) is used to perform one or both of the following steps: Step A: adsorbing carbon dioxide in the fluid flowing through the carbon dioxide adsorption / desorption unit (3) to obtain first condensate and fluid adsorbed by carbon dioxide; and Step B: desorbing the carbon dioxide adsorbed by the carbon dioxide adsorption / desorption unit (3) to obtain carbon dioxide rich in water vapor. The carbon dioxide compressor (7) is used to compress water vapor-rich carbon dioxide from the carbon dioxide adsorption / desorption unit (3) to obtain compressed carbon dioxide.

2. The industrial waste heat-driven direct air capture system as described in claim 1, characterized in that, It also includes a carbon dioxide dehydration unit (8), which is used to dehydrate the compressed carbon dioxide to obtain dehydrated carbon dioxide and fourth condensate.

3. The industrial waste heat-driven direct air capture system as described in any one of claims 1-2, characterized in that, The carbon dioxide-containing fluid is air.

4. The industrial waste heat-driven direct air capture system as described in any one of claims 1-2, characterized in that, The carbon dioxide adsorption / desorption unit (3) includes an adsorbent for adsorbing carbon dioxide.

5. The industrial waste heat-driven direct air capture system as described in any one of claims 1-2, characterized in that, The carbon dioxide adsorption / desorption unit (3) includes a reactor in which step A is performed when a carbon dioxide-containing fluid is introduced into the reactor, and step B is performed in the reactor when steam is introduced into the reactor. Alternatively, the carbon dioxide adsorption / desorption unit (3) includes at least a first reactor and a second reactor, the first reactor being used to implement step A and the second reactor being used to implement step B; wherein the first reactor includes an adsorbent for adsorbing carbon dioxide, and the adsorbent after adsorbing carbon dioxide in the first reactor can be transferred to the second reactor.

6. The industrial waste heat-driven direct air capture system as described in claim 1, characterized in that, It also includes a steam main pipe (11), a first steam expander inlet pipe (12) and a blower outlet pipe (13), wherein the first steam expander (2) is connected to the heat source (1) in sequence through the first steam expander inlet pipe (12) and the steam main pipe (11); The fan (4) includes an air inlet (41) and is connected to the carbon dioxide adsorption / desorption unit (3) through the fan outlet pipe (13) so that the air drawn in from the air inlet (41) is delivered to the carbon dioxide adsorption / desorption unit (3) under the action of the first steam expander (2). It also includes: the outlet pipe (14) of the first steam expander, the inlet pipe (15) of the steam-water separator, and the outlet pipe (16) of the steam-water separator, wherein, The first steam expander (2) is connected to the steam-water separator (5) in sequence through the first steam expander outlet pipe (14) and the steam-water separator inlet pipe (15) to transport the exhaust steam to the steam-water separator (5). The steam-water separator (5) is connected to the carbon dioxide adsorption / desorption unit (3) through the steam-water separator outlet pipe (16). The carbon dioxide adsorption / desorption unit (3) further includes an outlet (31) and a first condensate outlet (32) to discharge the separated fluid after carbon dioxide adsorption and the first condensate respectively.

7. The industrial waste heat driven direct air capture system as described in claim 1 further includes a second steam expander inlet pipe (17) and a second steam expander outlet pipe (18), wherein, The second steam expander (6) is connected to the heat source (1) through the second steam expander inlet pipe (17), and is connected to the steam-water separator (5) in sequence through the second steam expander outlet pipe (18) and the steam-water separator outlet pipe (16) to transport the exhaust steam generated by the second steam expander (6) to the steam-water separator (5); It also includes: a carbon dioxide compressor inlet pipe (19) and a carbon dioxide compressor outlet pipe (20), wherein the carbon dioxide adsorption / desorption unit (3) is connected to the carbon dioxide compressor (7) through the carbon dioxide compressor inlet pipe (19) to pressurize the carbon dioxide of the water-containing steam input from the carbon dioxide adsorption / desorption unit (3) under the action of the second steam expander (6); wherein the carbon dioxide compressor (7) is connected to the carbon dioxide dehydration unit (8) through the carbon dioxide compressor outlet pipe (20) to transport the pressurized carbon dioxide to the carbon dioxide dehydration unit (8) for dehydration; The carbon dioxide dehydration unit (8) also includes a carbon dioxide outlet (81) and a second condensate outlet (82) to discharge the separated dehydrated carbon dioxide and fourth condensate respectively.

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