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US-12623179-B2 - Rotary bed for direct capture of CO2 from air

US12623179B2US 12623179 B2US12623179 B2US 12623179B2US-12623179-B2

Abstract

Systems and methods are provided for performing direct air capture using a rotary sorbent bed configuration. The rotary sorbent bed is supported on a wheel that serves as a framework structure for supporting the sorbent bed. The sorbent bed can include one or more monoliths that form the support material for the sorbent bed, and a sorbent supported on the one or more monoliths. The rotational path of the sorbent bed passes through the enclosure that allows for sealing of the portion of the sorbent bed within the enclosure. Optionally, the enclosure can contain a plurality of sub-zones that facilitate temperature control and/or pressure control within the enclosure while allowing for recovery of a high purity CO 2 stream from the desorption zone. The rotary sorbent bed configuration can allow for continuous or semi-continuous capture of CO 2 while reducing or minimizing contact of the sorbent bed with oxygen at elevated temperature.

Inventors

  • Shelby Lux
  • Jessica L. Ross
  • Eric Simmers

Assignees

  • ExxonMobil Technology and Engineering Company

Dates

Publication Date
20260512
Application Date
20230821

Claims (14)

  1. 1 . A method of sorbing CO 2 , comprising: rotating a wheel framework structure that supports a sorbent bed, the sorbent bed comprising a support material comprising one or more monoliths and a sorbent having selectivity for sorption of CO 2 supported on the support material, the support material comprising a first surface, a second surface, and a plurality of channels providing a flow path between a first surface of the support material and a second surface of the support material, at least a portion of the sorbent being supported on one or more surfaces within the plurality of channels; exposing a first gas flow comprising 15 vol % to 25 vol % O 2 and 100 vppm to 650 vppm CO 2 to a first portion of the sorbent bed outside of the desorption zone volume, the first gas flow having a temperature of 0° C. to 40° C.; exposing a plurality of gas flows to a second portion of the sorbent bed within the desorption zone volume, the desorption zone volume defined by at least one cover plate and one or more cover plate seals, the one or more cover plate seals providing a) a seal between the at least one cover plate and the first surface of the support material, b) a seal between the at least one cover plate and the second surface of the support material, or c) a combination thereof, the exposing a plurality of gas flows to the second portion of the sorbent bed comprising sequentially exposing the second portion of the sorbent bed to: a purge gas flow to form a purge exhaust, and a steam flow having a temperature of 80° C. to 180° C. to form a CO 2 -containing output flow, wherein the rotating of the wheel framework structure changes the portions of the sorbent bed that correspond to the first portion of the sorbent bed outside of the desorption zone volume and the second portion of the sorbent bed within the desorption zone volume.
  2. 2 . The method of claim 1 , wherein the desorption zone volume comprises a plurality of sub-zones, each sub-zone comprising at least one of the plurality of gas flows.
  3. 3 . The method of claim 1 , wherein exposing the second portion of the sorbent bed to the plurality of gas flows comprises exposing the second portion of the sorbent bed to the plurality of gas flows sequentially in time.
  4. 4 . The method of claim 1 , wherein exposing the plurality of gas flows to the second portion of the sorbent bed further comprises exposing the second portion of the sorbent bed to a temperature adjustment flow after the steam flow, the temperature adjustment flow having a temperature 0° C. to 50° C. to form a temperature adjustment flow exhaust.
  5. 5 . The method of claim 4 , wherein a temperature of a leading edge of the second portion of the sorbent bed is 70° C. or higher after the exposing to the steam flow, and a temperature of a trailing edge of the second portion of the sorbent bed is 60° C. or lower prior to being rotated out of the desorption zone volume.
  6. 6 . The method of claim 4 , wherein exposing the plurality of gas flows to the second portion of the sorbent bed further comprises exposing the second portion of the sorbent bed to a second purge gas flow after the temperature adjustment flow.
  7. 7 . The method of claim 4 , wherein the temperature adjustment flow comprises a humidity of 25% or less relative to the temperature of the temperature adjustment flow.
  8. 8 . The method of claim 1 , wherein exposing the second portion of the sorbent bed to the steam flow further forms a liquid output product, or wherein the steam flow comprises substantially no liquid water content, or a combination thereof.
  9. 9 . The method of claim 1 , wherein the desorption zone volume comprises at least one internal seal, the at least one internal seal providing a seal between an interior surface of the one or more cover plates and at least one of the first surface and the second surface of the support material, the at least one internal seal defining a plurality of sub-zones within the desorption zone volume.
  10. 10 . The method of claim 1 , wherein a pressure inside the desorption zone volume is greater than a pressure outside the desorption volume by 2.0 kPa or more.
  11. 11 . The method of claim 1 , wherein a pressure inside the desorption zone volume is lower than a pressure outside the desorption zone volume by 20 kPa or more.
  12. 12 . The method of claim 1 , wherein at least one sub-zone of the desorption zone volume is separated from the first portion of the plurality of channels by at least one internal seal and at least one cover plate seal.
  13. 13 . The method of claim 1 , wherein the first gas flow impinges on at least one surface of the at least one cover plate of the desorption zone, the average direction of flow for the first gas flow in the sorption zone being substantially orthogonal to the at least one surface of the at least one cover plate of the desorption zone.
  14. 14 . The method of claim 1 , wherein rotating the wheel framework structure comprises continuously rotating the wheel framework structure.

Description

CROSS-REFERENCE TO RELATED APPLICATION This Non-Provisional Patent application claims priority to U.S. Provisional Patent Application No. 63/373,268, filed Aug. 23, 2022, and titled “ROTARY BED FOR DIRECT CAPTURE OF CO2 FROM AIR” the entire contents of which is incorporated herein by reference. FIELD Systems and methods are provided for using a rotary bed contactor for direct capture of CO2 from air. BACKGROUND Capture and sequestration of CO2 can contribute to efforts for reducing or minimizing the amount of CO2 introduced into the atmosphere by various commercial, residential, and/or industrial processes. One option is to attempt to capture CO2 as it is generated at various types of point sources. Another option is to attempt to remove CO2 directly from air. Some of the difficulties with direct air capture are related to the relatively low concentration of CO2 in the atmosphere. Typical CO2 concentrations in air are on the order of 400 volume parts per million (vppm). Due to the relatively low concentration of CO2 in comparison with other air components, achieving a high loading of CO2 at fast adsorbent rates in an adsorbent can be difficult, leading to increased material costs. Additionally, the amount of energy used per CO2 molecule captured can also be high, due in part to the relatively low density of CO2 that can be adsorbed in a typical adsorbent based on the low concentration of CO2 in the atmosphere. It would be beneficial to have improved systems and methods for capturing CO2 from air that can reduce or minimize the associated capital costs and/or energy requirements. In order to manage the plurality of flows that a sorbent is exposed to, there are two basic strategies. One strategy is to maintain the sorbent in a fixed volume corresponding to a sorbent environment, and then bring the various flow streams sequentially into the sorbent environment for contact with the sorbent. In this strategy, complex process flow management is needed so that the different flow streams do not mix while still reducing or minimizing the time required to switch between the various flow streams. An additional complication is that in order to have a continuous process, where air is continually taken in for CO2 removal, multiple sorbent beds in parallel are required. Each parallel bed increases the complexity of the piping and manifolds required for managing the process flows. The other option is to allow the sorbent to move, so that the piping for the process flows can be fixed. This has the advantage of simplifying the transport of the gas flows for the direct air capture process. However, conventional methods for allowing the sorbent to move to the gas flow have suffered from a variety of mechanical issues and/or difficulties with reliability. What is needed is an improved method for performing direct air capture that can simplify the handling of gas flows while still providing mechanical stability and reliability. U.S. Pat. No. 9,925,488 describes a direct air capture system with a plurality of monoliths arranged on a closed loop track. As the monoliths move around the track, CO2 is sorbed. One position on the track includes a box. If the box is at a different level than the track, the monolith is moved into the box, sealed in the box, and then exposed to conditions for desorption of CO2. The continuous removal and re-insertion of monoliths into the track creates the potential for mechanical and/or reliability difficulties. If the box is at the level of the track, the monolith moves into the box while forming a seal with the box to provide a sealed environment for CO2 desorption. Achieving the necessary seals to maintain the separate environment poses a variety of challenges. Additionally, scaling this type of design up to an appropriate size for commercial scale removal of CO2 may present structural design challenges. European Patent Publication 3725391 describes a direct air capture device that uses vertical adsorbent beds in a linear array, with start/stop movement of sliding doors surrounding the beds. The reliability of designs of this type are reduced by the start/stop movement of the process equipment along the linear array of beds, which typically requires complex hoses and mechanical swivel joints in the piping system to accommodate the movement of the process equipment. Requiring such movement of the process equipment is known to be less reliable than permanently installed, fixed piping and equipment. Reliable mechanical swivel joints are limited to small diameters, so this type of configuration is further limited by the fact that hoses with 1 end fixed and 1 end moving cannot make a 360° rotation without breaking. This explains why the equipment in this configuration moves in a linear fashion instead of in a closed loop, thereby increasing the cost of the process due to the unproductive time while the process equipment moves from the end of the adsorbent bed back to the beginning. It is noted that this t