Spiral mesh rotating bed absorber for compact carbon capture

Abstract

A carbon capture system configured to remove carbon dioxide from a carbonaceous feed stream includes a rotating bed absorber including a spiral rotating contactor inside a tank that is at least partially filled with a liquid solvent or absorbent. The helical rotary contactor includes one or more helical blades extending outwardly from a central hub. The rotating bed absorber is configured to produce a clean gas having a reduced carbon dioxide concentration and a loaded solvent from the feed stream. The carbon capture system may also optionally include a regenerator located downstream of the rotating bed absorber for regenerating the liquid absorbent.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 402,099, filed on August 30, 2022, entitled “Spiral Mesh Rotating Bed Absorberfor Compact Carbon Capture,” the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention generally relates to a carbon capture system and, more particularly, but not by way of limitation, to an improved system for contacting a carbonaceous feed stream with a suitable carbon capture solvent. Background Art

[0004] Carbon dioxide is the primary greenhouse gas emitted by human activities. In 2020, carbon dioxide accounted for approximately 79% of total U.S. anthropogenic greenhouse gas emissions. While a variety of carbon dioxide mitigation technologies exist, the use of liquid solvents and absorbents has been widely adopted. Amine-based solvents such as monoethanolamine (MEA) have been found to be particularly effective in capturing carbon dioxide.

[0005] In many cases, the carbon capture absorbent is fed into the contactor tower in a countercurrent manner to the carbonaceous feed stream. Filler materials can be loaded into the bed, which increases the contact area between the carbonaceous stream and the absorbent. The absorbent extracts the carbon from the feed gas before the gas is released from the tower. The loaded absorbent is transported from the contactor tower to a regeneration system that separates the carbon-based components from the absorbent. The regenerated absorbent can then be returned to the contactor tower in a cyclic process.

[0006] While these efforts have achieved some success, there remains a need for an improved system and method for contacting a carbon-based feed stream with a suitable absorbent. The present disclosure addresses these and other deficiencies in the prior art. Summary of the invention

[0007] In one aspect, the present disclosure relates to a carbon capture system configured to remove carbon dioxide from a carbonaceous feed stream such as a post-combustion gas feed stream. The carbon capture system includes a rotating bed absorber including a spiral rotating contactor. The rotating bed absorber is configured to produce a clean gas having a reduced carbon dioxide concentration and a loaded solvent from the feed stream. The post-combustion carbon capture system also includes a regenerator located downstream of the rotating bed absorber.

[0008] In another embodiment, the present disclosure relates to a carbon capture system configured to remove carbon dioxide from a carbonaceous feed stream, wherein the carbon capture system includes a rotating bed absorber and a regeneration module. The rotating bed absorber has a tank containing a liquid absorbent, a motor, and a spiral rotating contactor inside the tank. The spiral rotating contactor includes a central hub, one or more spiral blades extending away from the central hub, and a rotatable shaft connected to the central hub and driven by the motor.

[0009] In other embodiments, the present disclosure relates to a carbon capture system configured to remove carbon dioxide from a carbonaceous feed stream. The carbon capture system has a rotating bed absorber, which includes a tank at least partially filled with a liquid absorbent and a spiral rotating contactor inside the tank. The spiral rotating contactor includes a central hub, one or more spiral blades extending away from the central hub, and a rotatable shaft connected to the central hub and driven by a motor. The rotating bed absorber also includes a discharge port and an upper port, the discharge port is connected to the tank and is configured to remove a rich absorbent discharge flow from the rotating bed absorber, and the upper port is connected to the tank and is configured to remove a carbon-reduced gas flow from the rotating bed absorber and allow a lean solvent input flow to enter the tank. The carbon capture system may also include a regeneration module, which is configured to regenerate the liquid absorbent by heating the rich absorbent discharge flow to produce a hot lean solvent flow and a hot gas flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a process flow diagram of a carbon capture process for removing carbon dioxide from a carbon-containing feed stream.

[0011] Figure 2 is a perspective, partial cross-sectional view of a compact rotating bed absorber constructed in accordance with a first embodiment.

[0012] Figure 3 yes Figure 2 Top, partial cross-sectional view of a compact rotating bed absorber.

[0013] Figure 4 yes Figure 2 and Figure 3 A cross-sectional view of a portion of a spiral mesh element within a compact rotating bed absorber.

[0014] Figure 5 yes Figure 2 and Figure 3 A perspective view of the central hub of a compact rotating bed absorber.

[0015] Figure 6 is a perspective, partial cross-sectional view of a compact rotating bed absorber constructed in accordance with a second embodiment. DETAILED DESCRIPTION

[0016] Figure 1 1 is a process flow diagram describing a carbon capture system 100 designed to remove carbon dioxide (CO2) from a carbonaceous feed stream 102. Although the feed stream 102 is typically a flue gas or other post-combustion stream, the feed stream 102 may also originate from an open source that collects carbon dioxide. The feed stream 102 is conveyed to a rotating bed absorber 104 where it is mixed with a solvent injected from a lean solvent input stream 106. Clean gas with a reduced concentration of CO2 is discharged in a gas exhaust stream 108.

[0017] In some embodiments, the solvent is an amine-based solvent. Suitable solvents include mixtures of water and monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA) or potassium carbonate. In the present disclosure, the terms solvent, carbon capture solvent, absorbent and carbon capture absorbent can be used interchangeably. The loaded solvent is discharged from the rotating bed absorber 104 via a rich absorbent discharge stream 110. The rich absorbent discharge stream 110 is pressurized with a first pump 112 and passed through a heat exchanger 114, in which the rich absorbent discharge stream is heated and discharged as a hot rich absorbent stream 116.

[0018] The hot rich absorbent stream 116 is fed to a regeneration module 118, which can be configured as a rotating bed or a conventional stripper. The regeneration module 118 heats the loaded solvent to release carbon dioxide from the solvent. The stripped "lean" solvent is transported out of the regeneration module 118 in a hot lean absorbent stream 120. The hot lean absorbent stream 120 passes through a second pump 122 and a heat exchanger 114, where it transfers heat to the incoming rich absorbent vent stream 110 and becomes a lean solvent input stream 106. The released carbon dioxide gas is transported out of the regeneration module 118 in a hot gas stream 124.

[0019] Steering Figure 2 , which shows a description of a first embodiment of a rotating bed absorber 104. In this embodiment, the rotating bed absorber 104 includes a tank 126 having an upper port 128, a lower discharge port 130, and a gas inlet port 132. The tank 126 can be constructed as a cylindrical tank (as shown), a standard tank, or any other form that appropriately matches the rotating bed absorber 104. The gas inlet port 132 can be placed on the side of the tank 126 (as shown), the top of the tank 126, or the bottom of the tank 126. The rotating bed absorber 104 may include a plurality of gas inlet ports 132. In each case, the gas inlet port 132 is configured to receive a feed stream 102 of a carbonaceous fluid.

[0020] The rotating bed absorber 104 includes a spiral rotating contactor 134 inside the tank 126. The spiral rotating contactor 134 is connected to a shaft 136 driven by a motor 138. The shaft 136 can be made coaxial with the lower discharge port 130 so that the shaft 136 passes through the interior of the lower discharge port 130. In other embodiments, the shaft 136 and the lower discharge port 130 are not coaxial, and the shaft 136 and the lower discharge port 130 are connected to different locations on the tank 126. Figure 2 As shown, the lower discharge port 130 may be connected to a lower portion of the tank 126 and configured to convey the rich absorbent discharge stream 110 away from the rotating bed absorber 104 through an annular space surrounding an inner coaxial shaft 136 .

[0021] An upper port 128 extends through an upper portion of the tank 126. Figure 2 In the illustrated embodiment, the upper port 128 is positioned in a central location near the top of the spiral rotating contactor 134. The upper port 128 may be fixed or configured to rotate with the spiral rotating contactor 134. Figure 2 In the illustrated embodiment, the upper port 128 includes an inner passage 142 configured to convey the lean solvent input stream 106 to the center of the spiral rotating contactor 134 and an outer annular space 140 surrounding the inner passage 142 configured to remove the gas exhaust stream 108 from the rotating bed absorber 104. In other embodiments, the lean solvent input stream 106 and the gas exhaust stream 108 are conveyed through separate conduits connected to the rotating bed absorber 104.

[0022] Steering Figure 3 , which shows a top cross-sectional view of an embodiment of the rotating bed absorber 104. The spiral rotating contactor 134 includes one or more spiral blades 144 that extend outwardly from a perforated central hub 146 that is connected to the inner passage 142 of the upper port 128 or is otherwise in fluid communication with the inner passage. In some embodiments, the spiral blades 144 can approximate an Archimedean spiral, a golden spiral, or a Fibonacci spiral. The central hub 146 or another portion of the spiral rotating contactor 134 is connected to the shaft 136 and is configured to rotate with the shaft 136. Figure 2 and Figure 3 In the illustrated embodiment, the spiral rotating contactor 134 is configured to rotate in a clockwise direction when viewed from the top of the spiral rotating contactor 134.

[0023] During use, lean absorbent is delivered into the perforated central hub 146, discharged through the distribution ports 158 in the central hub 146, and carried outwardly within the channels 160 between adjacent spiral blades 144 under the action of centrifugal force. Figure 5As shown, the central hub 146 can include a plurality of discharge ports 158 that decrease in size from larger holes to smaller holes over the length of the central hub 146 to better distribute the lean solvent input stream 106. In other embodiments, the distribution holes 158 are of the same size. In still other embodiments, the distribution holes 158 at the top of the hub 146 are smaller than the distribution holes 158 at the bottom of the hub 146.

[0024] Simultaneously, the feed stream 102 is forced into the tank 126 and carried in counter-current flow opposite to the movement of the liquid absorbent to an area around the central hub 146 where the gas is discharged through the outer annular space 140 of the upper port 128. As the loaded solvent exits the spiral blades 144, it is captured within the tank 126 and collected for discharge through the lower discharge port 130 as the rich absorbent discharge stream 110. In this manner, the spiral rotating contactor 134 provides a very compact system for ensuring good contact and mixing between the lean solvent liquid and the carbonaceous feed gas in a counter-current manner.

[0025] To improve proper movement of the solvent through the spiral rotating contactor 134 and mixing between the carbonaceous gas and the liquid absorbent, the spiral blades 144 may be constructed of multiple layers of mesh, such as Figure 4 As shown. The outer layer 148 can be completely or partially liquid-impermeable, while the inner layer 150 can be composed of one or more layers of mesh that provide a friction interface to promote the outward movement of liquid solvent when the spiral rotating contactor 134 rotates. In some embodiments, the outer layer 148 is composed of PTFE plastic or of a variety of semi-permeable materials, and the inner layer 150 is composed of suitable stainless steel or other corrosion-resistant metals or alloys. In some embodiments, the mesh inner layer 150 partially extends between adjacent outer layers 150. In some embodiments, the spiral rotating contactor 134 includes a space or gap between the mesh inner layer 150 and the adjacent outer layer 148. In other embodiments, the mesh inner layer 150 extends completely between adjacent outer layers 148. In some embodiments, the mesh inner layer 150 extends both partially and completely between adjacent outer layers 148, depending on the position along one or more continuous spiral blades 144.

[0026] Steering Figure 5, which shows an alternative embodiment of a rotating bed absorber 104 in which a helical rotating contactor 134 rotates on a substantially horizontal axis 136 and is partially submerged in a volume of absorbent within a tank 126. The feed stream 102 is conveyed to the tank 126 through a gas inlet 154, and the lean solvent input stream 106 is injected through the absorbent inlet 152. In some applications, the gas inlet 154 can be configured to inject the feed stream 102 through the bottom of the tank 126 so that the gas is forced to bubble through the volume of liquid absorbent in the tank 126.

[0027] In this embodiment, the direction of rotation of the spiral rotating contactor 134 is reversed so that the open leading edge of the spiral blades 144 captures alternating volumes of gas and solvent with each successive rotation. In a periodic peristaltic or spiral pumping mechanism, the spiral rotating contactor 134 captures liquid absorbent and carbonaceous gas and mixes as the gas and liquid are transported inwardly to the central hub 146 together. The carbon-reduced gas and loaded liquid absorbent can be removed from the rotating bed absorber 104 through a discharge line 156 connected to the central hub 146 and conveyed to a separator module 162 to allow the gas and liquid components to separate by gravity. The carbon-reduced gas can be discharged or directed for downstream processing, while the loaded liquid absorbent can be directed through to a regeneration module 118, such as Figure 1 described.

[0028] It should be understood that although many features and advantages of various embodiments of the present invention, as well as details of the structure and function of various embodiments of the present invention have been set forth in the foregoing description, the present disclosure is illustrative only and that changes in detail may be made, particularly in the construction and arrangement of parts within the principles of the present invention, to the greatest extent indicated by the broad general meaning of the terms expressed in the appended claims. It should be understood by those skilled in the art that the teachings of the present invention may be applied to other systems without departing from the scope and spirit of the present invention. In particular, it should be noted that the novel rotating bed absorber 104 and spiral rotating contactor 134 may be configured for use in a variety of carbon capture systems 100 other than those disclosed herein.

Claims

1. A carbon capture system (100) configured to remove carbon dioxide from a carbon-containing feed stream (102), the carbon capture system (100) comprising: A rotating bed absorber (104), wherein the rotating bed absorber (104) comprises: a tank (126) containing a liquid absorbent; and a spiral rotating contactor (134) inside the tank; and Regeneration module (118).

2. The carbon capture system (100) of claim 1, wherein the spiral rotating contactor (134) comprises a plurality of mesh layers (148, 150) arranged in one or more spiral blades (144).

3. The carbon capture system of claim 2, wherein the spiral rotating contactor (134) includes a continuous channel (160) between each of the one or more spiral blades (144).

4. The carbon capture system (100) of claim 1, wherein the spiral rotating contactor (134) comprises: one or more outer layers (148), the one or more outer layers being liquid impermeable; and One or more inner layers (150), each of the one or more inner layers being formed from a mesh material.

5. The carbon capture system (100) of claim 1, wherein the helical rotating contactor (134) comprises a central hub (146) comprising a plurality of exhaust ports (158).

6. The carbon capture system (100) of claim 1, wherein the helical rotating contactor (134) is configured to rotate on a substantially vertical axis.

7. The carbon capture system (100) of claim 6, wherein the spiral rotating contactor (134) is immersed in the liquid absorbent inside the tank (126).

8. The carbon capture system (100) of claim 1, wherein the helical rotating contactor (134) is configured to rotate on a substantially horizontal axis.

9. The carbon capture system (100) of claim 8, wherein the spiral rotating contactor (134) is partially submerged in the liquid absorbent inside the tank (126).

10. The carbon capture system (100) of claim 9, wherein the spiral rotating contactor (134) is configured as a periodic peristaltic pump that captures and mixes alternating volumes of the carbonaceous feed stream and the liquid absorbent from the tank (126), and removes the mixed carbonaceous feed stream and liquid absorbent from the tank (126).

11. The carbon capture system (100) of claim 10, wherein the carbon capture system (100) further comprises a separation module (118) connected to the tank (126) and configured to separate liquid and gas components in the mixed carbonaceous feed stream (102) removed from the tank by the spiral rotating contactor (134).

12. The carbon capture system (100) of claim 1, wherein the liquid absorbent is selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and potassium carbonate.

13. The carbon capture system (100) of claim 1, further comprising a heat exchanger (114) between the rotating bed absorber (104) and the regeneration module (118).

14. The carbon capture system (100) of claim 1, wherein the rotating bed absorber (104) further comprises an upper port (128) having a coaxially positioned inner channel (142) and an annular space (140) surrounding the inner channel (142), wherein the inner channel (142) is connected to a lean solvent input stream (106), and the annular space (140) allows removal of a gas exhaust stream (108) from the rotating bed absorber (104).

15. The carbon capture system (100) of claim 1, wherein the spiral rotating contactor (134) comprises one or more spiral blades (144), each of the one or more spiral blades being substantially configured as an Archimedean spiral, a golden spiral, or a Fibonacci spiral.

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