CO2 enrichment treatment system and method

Abstract

A system for separating carbon dioxide from a carrier gas includes a CO2 enrichment subsystem that receives a carrier gas stream and produces an enriched carbon dioxide fluid stream. The system further includes a CO2 polishing subsystem in fluid communication with the CO2 enrichment subsystem that produces a fluid stream enriched in carbon dioxide. In a corresponding method, a carrier gas is received at the CO2 enrichment subsystem and an enriched carbon dioxide fluid stream is produced. The enriched carbon dioxide fluid stream is directed to the CO2 polishing subsystem where a stream further enriched in carbon dioxide is produced.

Description

Technical Field

[0001] Priority Claim

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 211,182, filed Jun. 16, 2021, the content of which is incorporated herein by reference.

[0002]

[0002] The present disclosure generally relates to systems and methods for gas purification, and more particularly, to systems and methods for separating carbon dioxide from a carrier gas stream and purifying the separated carbon dioxide stream.

Background Art

[0003]

[0003] For example, the removal of carbon dioxide from carrier gas streams such as flue gas streams, process streams, and / or waste streams generated by gas turbines, coal power plants, cement factories, heating heaters, and other carbon combustion processes is desirable because carbon dioxide is generally considered to be a significant factor in increasing the greenhouse effect and global warming. High purity carbon dioxide streams are desirable because they enable efficient injection of carbon dioxide into wells for sequestration and are also useful for enhanced oil recovery in cement factories and other processes.

Summary of the Invention

Means for Solving the Problems

[0004]

[0004] There are several embodiments of the subject matter that may be implemented separately or in combination in the apparatus and systems described and claimed below. These embodiments may be used alone or in combination with other embodiments of the subject matter described herein, and the description of these embodiments in combination is not intended to exclude the use of these embodiments separately or claims of such embodiments separately or in different combinations as discussed in the claims appended herein.

[0005]

[0005] In one embodiment, a system for separating carbon dioxide from a carrier gas includes a CO2 enrichment subsystem configured to receive a carrier gas flow and generate an enriched carbon dioxide fluid flow. The system further includes a CO2 polishing subsystem that is in fluid communication with the CO2 enrichment subsystem and configured to generate a carbon dioxide-rich fluid flow.

[0006]

[0006] In another embodiment, a process for separating carbon dioxide from a carrier gas includes the steps of receiving the carrier gas in a CO2 enrichment subsystem, generating an enriched carbon dioxide fluid flow in the CO2 enrichment subsystem, directing the enriched carbon dioxide fluid flow to a CO2 polishing subsystem, and generating a carbon dioxide-rich fluid flow in the CO2 polishing subsystem. [Brief explanation of the drawing]

[0007] [Figure 1]

[0007] This is a process flow diagram in a first embodiment of the system and method of the present disclosure. [Figure 2]

[0008] This is a process flow diagram in a second embodiment of the system and method of the present disclosure. [Modes for carrying out the invention]

[0008]

[0009] While this disclosure refers to the treatment of exhaust gas flows below, the technology may be used for the treatment of any transport gas flows containing carbon dioxide, including, but not limited to, process flows and / or waste flows.

[0009]

[0010] A first embodiment of the system of this disclosure is shown overall in Figure 1, 5. A carrier gas flow, such as an exhaust gas flow 10, enters the CO2 enrichment subsystem 12, thereby concentrating and producing an enriched carbon dioxide gas flow 14 at low pressure. This is merely an example. The enriched carbon dioxide gas flow may contain approximately 350% to 98% carbon dioxide. This is merely an example, but the flow 14 may contain approximately 90% carbon dioxide in moles at atmospheric pressure.

[0010]

[0011] Systems suitable for use as a CO2 enrichment subsystem 12 are known in the art by examples including, but not limited to, metal-organic framework (MOF) technology, membranes, adsorbents, process modifications (recirculating fluids, chemical looping, etc.), and / or MOF processes, or other technologies, available from Svante Inc. in Burnaby, British Columbia, Canada. The subsystem 12 into which CO2 is enriched further, or in addition, provides Sustainable Energy Solutions, Inc.'s U.S. Patent Nos. 8,715,401, 8,764,885, 9,250,012, 9,410,736, 10,213,731, 10,195,615, 10,399,092, 10,328,384, 10,537,843, 10,458,704, 10,549,229, 10,724,793, 10,739,067, This may include the technologies disclosed in U.S. Patent Publication Nos. 10,807,924, 10,969,169, and / or U.S. Patent Application Publication Nos. 2018 / 0031315, 2020 / 0018545, 2020 / 0018546, 2020 / 0298179, 2020 / 0316547, and / or 2020 / 0318900, all of which belong to Sustainable Energy Solutions, Inc., and the contents of each of these patents are incorporated herein by reference.

[0011]

[0012] The enriched carbon dioxide flow 14 is then compressed in one or more compressors 16, each compressor may have one or more compression stages. Prior to each compression, the flow 14 may optionally be cooled. In some embodiments, the flow 14 may be cooled and compressed in some stages by intermediate free water knockout between stages. For example, air coolers or water coolers may be used for interstage cooling.

[0012]

[0013] The pressurized and enriched carbon dioxide stream 18 flows to an optional dehydration unit, such as a molecular sieve unit 22. The dehydration unit 22 removes any remaining uncondensed water from the carbon dioxide stream to a sufficient extent to prevent coagulation and hydrate formation in the distillation column 26, as described below. In alternative embodiments, the dehydration unit 22 may be positioned before one or more compressors 16 (i.e., between the CO2 enriched subsystem 12 and the compressor 16 in Figure 1), or, when multiple compression stages or multiple compressors 16 are used, the dehydration unit 22 may be positioned between multiple compression stages or multiple compressors.

[0013]

[0014] The resulting dehydrated flow 24 is directed to one or more distillation columns 26, which are part of the CO2 polishing subsystem 28 as a whole. In subsequent discussions, the characteristics and operation of the distillation columns 26 will be understood to apply to each column if the CO2 polishing subsystem 28 includes multiple distillation columns.

[0014]

[0015] In an alternative embodiment, the dehydration unit 22 in Figure 1 may be omitted, and the pressurized and enriched carbon dioxide stream 18 flows directly into the distillation column 26. In such an embodiment, the distillation column 26 may optionally be provided with an optional liquid water discharge section 32, or a decanting container or tray, for phase separation of liquid water from CO2.

[0015]

[0016] The distillation column 26 may operate between 20 and 60 bar, for example, at approximately 40 bar. In the distillation column 26, carbon dioxide is separated from the remaining components of flow 24 (or flow 18 if the dehydration unit 22 is omitted).

[0016]

[0017] The resulting lower liquid flow 34 exits the bottom of the distillation column 26 and proceeds to the reboiler 36 (which may be heated by ambient air or another heating fluid), where a portion of the flow 34 is evaporated and returned to the column as flow 38. The carbon dioxide-rich liquid flow 42 exits the bottom of the reboiler 36 and, simply as an example, contains approximately 90% to approximately 99% carbon dioxide and approximately less than parts per million (ppm) (mass) of oxygen. The reboiler ensures that the liquid carbon dioxide product meets the <10 ppm (mass) oxygen specification. Simply as an example, this specification sets the reboiler temperature at +5°C for 40 bar.

[0017]

[0018] Pump 44 may optionally be provided to direct a carbon dioxide-rich liquid flow 42 to a user, user, or transport pipeline. Simply as an example, the lower column product is 152.7 bar (152.7 × 10⁻⁶). 5 It can be pumped by the pump 44 into a transport pipeline operating at Pa (2,215 psia).

[0018]

[0019] The vapor stream 46 exiting the top of the distillation column 26 proceeds to a condenser 48, which is cooled by a refrigerant that is colder than the boiling point (bubble point) of carbon dioxide, or colder than liquid carbon dioxide, at the operating pressure of the distillation column 26. For example, the refrigerant could be propane, R134a, or HFO-1234yf. The condensed stream 50 proceeds to return to the column 26 for use as reflux.

[0019]

[0020] The vapor from column 26 that cannot be condensed by the refrigerant in condenser 48 is recirculated as a recirculation flow 52 to the CO2 enrichment subsystem 12 via pipeline 54 in order to increase carbon dioxide concentration. Cooling can be recovered from the top distillate vapor flow because the vapor flow is reduced to the supply pressure of the CO2 enrichment subsystem 12.

[0020]

[0021] The temperature of the overhead condenser 48 of the distillation column is set to -38°C by a selected refrigerant, such as propane. The condenser temperature can alternatively be set to a carbon dioxide fraction of 37% (mol) in the overhead vapor of the column. The propane loop for the condenser 48 assumes water cooling to condense propane.

[0021]

[0022] A lower overhead temperature will slightly reduce the carryover of carbon dioxide until the temperature reaches the freezing point of carbon dioxide at approximately -56°C in this pressure range. However, this will require a more expensive refrigerant system.

[0022]

[0023] In an alternative embodiment, the recycle stream 52 can be used to regenerate a second molar sieve dehydration unit (or other type of dehydration unit) 56 via line 58 and then be directed back to the CO2 enrichment subsystem 12 via line 62. In such an embodiment, the second dehydration unit 56 can be used in place of dehydration unit 22 when unit 22 requires regeneration after regeneration. The system can then be reconfigured such that the vapor in line 58 proceeds to dehydration unit 22 and then from unit 22 through line 62 to the CO2 enrichment subsystem. Alternatively, air can be used to regenerate the dehydration units (22 and 56), but this will require additional equipment not illustrated.

[0023]

[0024] In another alternative embodiment, the vapor stream 52 can be exhausted directly from the column 26 (through the exhaust line 64) or, alternatively, after being used to regenerate dehydration unit 22 or 56. The exhaust line 64 can further be used in combination with the recycle line 54 and / or the regeneration line 58 by appropriate valve adjustment.

[0024]

[0025] A second embodiment of the system of this disclosure is shown overall in Figure 2, indicated by 100. As illustrated in Figure 2, a carrier gas flow, such as an exhaust gas flow 110, enters the CO2 enrichment subsystem 112, thereby enriching a carbon dioxide gas flow 114 at low pressure and producing it. As merely an example, the enriched carbon dioxide gas flow may contain approximately 35% to 98% carbon dioxide. Suitable systems for use as the CO2 enrichment subsystem 112 include metal-organic framework (MOF) technology, membranes, adsorbents, process modifications (recirculating flow, chemical looping, etc.), and / or MOF processes, or other technologies, available from Svante Inc. in Burnaby, British Columbia, Canada, and / or Sustainable Energy Solutions, Inc.'s U.S. Patent Nos. 8,715,401, 8,764,885, 9,250,012, 9,410,736, 10,213,731, 10,195,615, 10,399,092, 10,328,384, 10,537,843, 10,458,704, 10,549,229, 10,724,793, 10,739,067, 10,807,924, 10, Known in the art by examples including, but not limited to, the technologies disclosed in U.S. Patent Publication Nos. 969,169, and / or U.S. Patent Application Publication Nos. 2018 / 0031315, 2020 / 0018545, 2020 / 0018546, 2020 / 0298179, 2020 / 0316547, and / or 2020 / 0318900, all of which belong to Sustainable Energy Solutions, Inc., and the contents of each of these patents are incorporated herein by reference.

[0025]

[0026] Flow 114 is then directed to a CO2 polishing subsystem, which in the embodiment shown in Figure 2 is a cryogenic carbon capture system, as indicated overall at 128.

[0026]

[0027] The CO2 polishing subsystem 128 may include, by way of example only, the cryogenic carbon recovery technology disclosed in U.S. Patent No. 9,410,736, which belongs to Sustainable Energy Solution, Inc., and the content of that U.S. Patent is hereby incorporated by reference. The CO2 polishing subsystem 128 may further or additionally include the technologies disclosed in U.S. Patent Nos. 8,715,401, 8,764,885, 9,250,012, 10,213,731, 10,195,615, 10,399,092, 10,328,384, 10,537,843, 10,458,704, 10,549,229, 10,724,793, 10,739,067, 10,807,924, 10,969,169, and / or U.S. Patent Application Publication Nos. 2018 / 0031315, 2020 / 0018545, 2020 / 0018546, 2020 / 0298179, 2020 / 0316547, and / or 2020 / 0318900, all of which belong to Sustainable Energy Solutions, Inc., and the content of each of those patent documents is hereby incorporated by reference. The CO2 polishing subsystem 128 may further or additionally incorporate an alcohol dryer.

[0027]

[0028] The CO2 polishing subsystem 128 may or may not have a vapor phase due to residual carbon dioxide. If a significant residual amount of vapor carbon dioxide is present, that carbon dioxide is exhausted through line 132, or otherwise may be recycled to the CO2 enrichment subsystem 112 as directed by line 134. The CO2 polishing subsystem 128 further, by way of example only, produces a high purity liquid carbon dioxide stream 136 with a low oxygen content, such as approximately greater than 90% to approximately greater than 99% carbon dioxide and approximately less than 10 ppm (by mass) oxygen, in a manner prepared to be pumped through an optional pump 138 to the ultimate destination of that stream 136.

[0028]

[0029] While preferred embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that modifications and changes can be made in those embodiments without departing from the spirit of the invention.

Claims

1. A system for separating carbon dioxide from a transport gas, a. A CO2 system configured to receive a transport gas flow and generate an enriched carbon dioxide fluid flow. ２ Enrichment subsystem and b. The aforementioned CO ２ CO2 is configured to be in fluid communication with the enrichment subsystem and generate a carbon dioxide-rich fluid flow. ２ Polishing subsystem and Includes, The CO2 polishing subsystem includes a distillation column that is in fluid communication with the CO2 enrichment subsystem, and the distillation column is configured to concentrate CO2 as a liquid in the lower flow and concentrate light gas as a distillation flow. The system further includes a condenser configured such that vapor from the distillation column is directed as a recirculating flow to the CO2 enrichment subsystem. system.

2. The aforementioned CO ２ The enrichment subsystem uses a metal-organic structure, a membrane, an adsorbent, or a process modification to generate the enriched carbon dioxide fluid flow, according to claim 1.

3. The system according to claim 1, wherein the conveying gas is selected from the group consisting of exhaust gas, process flow, and waste flow.

4. The system according to claim 1, wherein the enriched carbon dioxide fluid flow includes a gas flow containing 35% to 98% carbon dioxide.

5. The aforementioned CO ２ The system according to claim 1, wherein the polishing subsystem uses low-temperature carbon recovery to generate the carbon dioxide-rich fluid flow.

6. The system according to claim 1, wherein the carbon dioxide-rich fluid flow includes a liquid flow containing more than 90% to more than 99% carbon dioxide.

7. The system according to claim 1, wherein the carbon dioxide-rich fluid flow includes a liquid flow containing less than 10 ppm (by mass) of oxygen.

8. The system according to claim 1, wherein the condenser refrigerant is selected from the group consisting of propane, R134a, and HFO-1234yf.

9. The system further includes a dewatering unit that receives the recirculating flow for regeneration, wherein, after regeneration, the dewatering unit receives at least a portion of the recirculating flow, the CO2 ２ The system according to claim 1, configured to direct to an enrichment subsystem.

10. The aforementioned CO ２ The polishing subsystem comprises a plurality of distillation columns, according to claim 1.

11. CO ２ The system according to claim 1, further comprising a decanting container or tray for phase-separating liquid water from a liquid water.

12. The enriched carbon dioxide fluid stream is fed to the CO ２ receives from the enrichment subsystem and further includes a dehydration unit configured to direct the dehydrated enriched carbon dioxide fluid stream to the CO ２ The system according to claim 1, further comprising a dehydration unit configured to direct the dehydrated enriched carbon dioxide fluid stream to the polishing subsystem.

13. The enriched carbon dioxide fluid flow is the CO ２ The system further includes a compressor configured to receive from an enrichment subsystem and generate a pressurized enriched carbon dioxide fluid flow, wherein the compressor receives the CO ２ The system according to claim 12, further comprising a compressor outlet in fluid communication with a polishing subsystem.

14. The system according to claim 13, further comprising a dewatering unit having fluid communication with the compressor.

15. The system further includes a compressor and a dewatering unit, wherein the compressor processes the enriched carbon dioxide fluid flow through the CO ２ The enrichment subsystem receives a pressurized enriched carbon dioxide fluid stream, which is configured to be directed to the dewatering unit, and the dewatering unit compresses and dewaters the enriched carbon dioxide fluid stream, the CO ２ The system according to claim 1, configured to direct to a polishing subsystem.

16. The system according to claim 1, further comprising a pump configured to receive the carbon dioxide-rich fluid flow.

17. A method for separating carbon dioxide from a transport gas, a. The transport gas is CO ２ Steps received in the enrichment subsystem, b. The enriched carbon dioxide fluid flow is the CO ２ Steps to be generated in the enrichment subsystem, c. The enriched carbon dioxide fluid flow is CO ２ Steps directed towards the polishing subsystem, d. The flow further enriched in carbon dioxide, the CO ２ Steps generated in the polishing subsystem, Includes, The CO2 polishing subsystem includes a distillation column that is in fluid communication with the CO2 enrichment subsystem, and the distillation column is configured to concentrate CO2 as a liquid in the lower flow and concentrate light gas as a distillation flow. The vapor from the distillation column is directed by the condenser as a recirculating flow to the CO2 enrichment subsystem. method.

18. The method according to claim 17, wherein step b. includes using a metal-organic structure, a membrane, an adsorbent, or a process modification to generate the enriched carbon dioxide fluid flow.

19. The method according to claim 17, wherein the conveying gas is exhaust gas, process flow, or waste flow.

20. The method according to claim 17, wherein the enriched carbon dioxide fluid flow includes a gas flow containing 35% to 98% carbon dioxide.

21. The method according to claim 17, wherein step d. includes using low-temperature carbon capture to generate the carbon dioxide-rich fluid flow.

22. The method according to claim 17, wherein step d. includes the step of using the distillation column.

23. The method according to claim 17, wherein the carbon dioxide-rich fluid flow includes a liquid flow containing more than 90% to more than 99% carbon dioxide.

24. The method according to claim 17, wherein the carbon dioxide-rich fluid flow includes a liquid flow containing less than 10 ppm (by mass) of oxygen.

25. The method according to claim 17, further comprising the step of compressing the enriched carbon dioxide fluid flow.

26. The method according to claim 17, further comprising the step of dewatering the enriched carbon dioxide fluid stream.

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