Segmented reactors for carbon dioxide capture and methods of capturing carbon dioxide using segmented reactors

A reactor for adsorbing CO2 from a fluid stream includes a reactor housing having a fluid inlet and a fluid outlet. The reactor also includes an inlet ceramic honeycomb structure and an outlet ceramic honeycomb structure positioned inside the reactor housing. The inlet and outlet ceramic honeycomb structures have a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels and comprises a material that forms bonds with CO2 to adsorb the CO2. The inlet ceramic honeycomb structure is capable of adsorbing an inlet quantity of CO2 and the outlet ceramic honeycomb structure is capable of adsorbing an outlet quantity of CO2. The inlet quantity of CO2 is greater than the outlet quantity of CO2.

BACKGROUND

The present specification generally relates to reactors for capturing carbon dioxide (CO2) from a gas stream and, more specifically, to reactors having segmented honeycomb structures for adsorbing CO2.

2. Technical Background

Natural gas is extracted from deposits to provide fuel for a variety of applications including home heating and cooking. In general, methane is the primary component of the natural gas that is used for fuel. As extracted from deposits, however, natural gas includes several other substances that are mixed with the methane extracted from the deposits. Such substances can include water, carbon dioxide (CO2), hydrogen sulfide, liquid hydrocarbon condensate, and heavier gaseous hydrocarbons such as ethane, propane, and butane. Many of these substances are separated from the methane before the fuel is delivered to customers.

Various technologies are currently being used and/or developed to improve the capture of CO2from process gas streams. Such technologies include, for example, a liquid amine (MEA or KS-1) process, a chilled ammonia process, and gas membranes. While each of these technologies is effective for removing CO2from a process gas stream, each technology also has drawbacks. The chilled ammonia process is still in its early phases of development and the commercial feasibility of the process is not yet known. Some possible challenges with the chilled ammonia process include ammonia volatility and the potential contamination of the ammonia from gaseous contaminants such as SOxand NOx. Various gas membrane technologies are currently employed for the removal of CO2from process gas streams. However, processes utilizing gas membrane technologies require multiple stages and/or recycling in order to achieve the desired amount of CO2separation. These multiple stages and/or recycling add significant complexity to the CO2recovery process as well as increase the energy consumption and cost associated with the process. Gas membrane technologies also typically require high pressures and associated space constraint which makes use of the technology difficult in installations with limited space such as offshore platforms.

Accordingly, a need exists for alternative methods and apparatuses which may be used to recover CO2from process gas streams.

SUMMARY

According to various embodiments, a reactor for adsorbing CO2from a fluid stream includes a reactor housing having a fluid inlet and a fluid outlet. The reactor also includes an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet. The inlet ceramic honeycomb structure has a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels. The inlet ceramic honeycomb structure includes a material that forms bonds with CO2to adsorb the CO2. The inlet ceramic honeycomb structure is capable of adsorbing an inlet quantity of CO2. The reactor further includes an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing. The outlet ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels. The outlet ceramic honeycomb structure includes a material that forms bonds with CO2to adsorb the CO2. The outlet ceramic honeycomb structure is capable of adsorbing an outlet quantity of CO2, and the inlet quantity of CO2is greater than the outlet quantity of CO2.

According to further embodiments, a reactor for adsorbing CO2from a fluid stream includes a reactor housing having a fluid inlet and a fluid outlet. The reactor also includes an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet. The inlet ceramic honeycomb structure has a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels and the inlet ceramic honeycomb structure includes a material that forms bonds with CO2to adsorb the CO2such that the inlet ceramic honeycomb structure has an inlet mass transfer velocity. The reactor further includes an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing. The outlet ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels. The outlet ceramic honeycomb structure includes a material that forms bonds with CO2to adsorb the CO2such that the outlet ceramic honeycomb structure has an outlet mass transfer velocity. For a constant mass flow rate of a fluid stream containing CO2, the inlet mass transfer velocity is greater than the outlet mass transfer velocity.

According to still further embodiments, the disclosure provides a method of removing CO2from a fluid stream that includes introducing the fluid stream to a reactor, where the reactor comprises a reactor housing having a fluid inlet and a fluid outlet, an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet of the reactor housing, and an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing. The inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure have a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels and comprise a material that forms bonds with CO2to adsorb the CO2. The inlet and outlet ceramic honeycomb structures include material that forms bonds with CO2to adsorb the CO2, such that the inlet and the outlet ceramic honeycomb structures are capable of adsorbing an inlet quantity and an outlet quantity of CO2, respectively. The inlet quantity of CO2is greater than the outlet quantity of CO2. The method also includes flowing the fluid stream from the fluid inlet to the fluid outlet of the reactor housing such that the fluid stream flows through the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure, where the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure have an affinity for CO2. The method further includes sensing a chemical composition of a portion of the fluid stream flowing out of the fluid outlet of the reactor housing, and terminating the fluid stream from flowing into the reactor when CO2breakthrough is sensed.

Additional features and advantages of the embodiments described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description that follows, the claims, as well as the appended drawings.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of reactors having segmented ceramic honeycomb structures for capturing CO2, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. One example of the reactor for capturing CO2from a fluid stream is schematically depicted inFIGS. 1 and 2. The reactor generally includes a reactor housing having a fluid inlet and a fluid outlet, an inlet ceramic honeycomb structure positioned inside the reactor proximate to the fluid inlet, and an outlet ceramic honeycomb structure positioned inside the reactor proximate to the fluid outlet. The inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure include a material that forms bonds with CO2to adsorb CO2from the fluid stream. The inlet ceramic honeycomb structure adsorbs an inlet quantity of CO2and the outlet ceramic honeycomb structure adsorbs an outlet quantity of CO2, where the inlet quantity is greater than the outlet quantity. Reactors according to the current disclosure may exhibit enhanced efficiency of utilization of adsorbent material as compared with reactors having uniform distribution of adsorbent material. The reactors and methods of capturing CO2will be described in more detail herein with specific reference to the appended drawings.

Referring now toFIGS. 1 and 2, a reactor100is depicted. The reactor100includes a reactor housing102having a fluid inlet104and a fluid outlet106positioned distally from the fluid inlet104. A fluid stream is introduced to the reactor100at the fluid inlet104and exits at the fluid outlet106. The reactor100includes an inlet ceramic honeycomb structure110positioned inside the reactor housing102at a position proximate to the fluid inlet104. The inlet ceramic honeycomb structure110includes a plurality of partition walls112extending in an axial direction108. The plurality of partition walls112form a plurality of flow channels114, similarly extending in the axial direction108. The partition walls112may be formed in an extrusion process, such that the flow channels114have approximately the same dimensions at all positions along the axial direction108. The inlet ceramic honeycomb structure110may also include a skin layer116surrounding the plurality of flow channels114. The skin layer116may be formed during the formation of the partition walls112or formed in later processing as an after-applied skin layer, such as applying skinning cement to the outer peripheral portion of the flow channels114.

The reactor100also includes an outlet ceramic honeycomb structure120positioned inside the reactor housing102at a position proximate to the fluid outlet106. In the embodiment depicted inFIG. 2, the outlet ceramic honeycomb structure120is axially offset from the inlet ceramic honeycomb structure110. The outlet ceramic honeycomb structure120includes a plurality of partition walls122extending in the axial direction108. The plurality of partition walls122form a plurality of flow channels124, similarly extending in the axial direction108. Further, the outlet ceramic honeycomb structure120may include a skin layer126surrounding the plurality of flow channels124.

The plurality of flow channels114,124in the inlet and outlet ceramic honeycomb structures110,120, respectively, may have a variety of shapes including having cross sections that are square, rectangular, round, oblong, triangular, octagonal, hexagonal, or combinations thereof. The flow channels114,124extend along the length of the inlet or outlet ceramic honeycomb structures110,120, such that a fluid stream introduced to the reactor100contacts the flow channels114,124along the length of the inlet and outlet ceramic honeycomb structures110,120. In embodiments described herein, the inlet and outlet ceramic honeycomb structures110may be formed with a channel density of up to about 1600 channels per square inch (cpsi). For example, in some embodiments, the inlet and outlet ceramic honeycomb structures110,120may have a channel density in a range from about 100 cpsi to about 2000 cpsi. In some embodiments, the inlet and the outlet ceramic honeycomb structures110,120may have different channel densities. For example, in one embodiment, the inlet ceramic honeycomb structure110may be formed with an inlet cell density in a range from about 900 to about 2000 cpsi, and the outlet ceramic honeycomb structure120may be formed with an outlet cell density in a range from about 100 to about 900 cpsi. As such, the amount of CO2adsorbing material in the inlet ceramic honeycomb structure110is greater than the amount of CO2adsorbing material in the outlet ceramic honeycomb structure120.

In some embodiments, the channel size and the channel density can be varied between the inlet and outlet ceramic honeycomb structures110,120to provide a reactor100having the desired pressure drop from the fluid inlet104to the fluid outlet106. For example, the inlet ceramic honeycomb structure110may have dimensionally smaller flow channels114than the outlet ceramic honeycomb structure120, which results in an inlet pressure drop. The comparatively larger flow channels124of the outlet ceramic honeycomb structure120may decrease the pressure drop across the outlet ceramic honeycomb structure120, which results in an outlet pressure drop. The inlet pressure drop may be greater than the outlet pressure drop for the same mass flow rate of the fluid stream across both the inlet and the outlet ceramic honeycomb structures110,120.

The inlet ceramic honeycomb structure110and the outlet ceramic honeycomb structure120include a material that forms bonds with CO2, while allowing other components in the fluid stream to pass without bonding with the inlet ceramic honeycomb structure110and the outlet ceramic honeycomb structure120. Such materials may form partition walls112,122that have pores, thereby increasing the surface area of each of the flow channels114,124as compared with the overall geometric dimensions of each of the flow channels114,124. In some embodiments, the inlet and outlet ceramic honeycomb structures110,120are made from materials that are adapted to adsorb CO2from the fluid stream. Such materials are suitable for adsorbing CO2from the fluid stream and may include, without limitation, molecular sieve materials having framework structures such as MFI, MOR, ISV, ITE, CHA, DDR, FAU, and/or LTA framework structures and similar materials. Exemplary materials include, without limitation, ZSM5 zeolite which has an MFI framework structure, and Mordenite which has an MOR framework structure. The sorbent materials may also include sorbents based on activated carbon or carbon molecular sieve materials. Alternatively, the sorbent material may be selected from a metallic organic framework (MOF) family such as MOF-5, MOF-177, MOF-505, MOF-74 or zeolitic imidazole framework structures (ZIFs) including, without limitation, ZIF-68, ZIF-69, ZIF-7, ZIF-9, ZIF-11 and ZIF-90. Suitable sorbent materials may also include any of the aforementioned materials functionalized with a polymer having an amine or amino group that are mixed with the ceramic to further enhance the adsorption capacity of the material.

In some embodiments, the inlet and outlet ceramic honeycombs110,120may be made from a ceramic substrate material to which a functional coating adapted to adsorb CO2from the fluid stream is applied. Such ceramic substrate materials include, for example, cordierite, aluminum titanate, and silicon carbide, in addition to the materials listed above that are adapted to adsorb CO2. Examples of such materials that may be used as the functional coating include, without limitation, molecular sieve materials having framework structures such as MFI, MOR, ISV, ITE, CHA, DDR, FAU, and/or LTA framework structures and similar materials. Exemplary materials include, without limitation, ZSM5 zeolite which has an MFI framework structure, and Mordenite which has an MOR framework structure. The sorbent materials may also include sorbents based on activated carbon or carbon molecular sieve materials. Alternatively, the sorbent material may be selected from a metallic organic framework (MOF) family such as MOF-5, MOF-177, MOF-505, MOF-74 or zeolitic imidazole framework structures (ZIFs) including, without limitation, ZIF-68, ZIF-69, ZIF-7, ZIF-9, ZIF-11 and ZIF-90. Suitable sorbent materials may also include any of the aforementioned materials functionalized with a polymer having an amine or amino group that are mixed into the functional coating to further enhance the adsorption capacity of the functional coating.

The functional coating may be applied onto the partition walls112,122of the inlet and outlet ceramic honeycomb structures110,120by a washcoating process such that the functional coating surrounds the flow channels114,124of the inlet and outlet ceramic honeycomb structures110,120. The functional coating may be deposited onto the partition walls112,122by first forming a slurry containing the functional coating in a liquid vehicle, such as water. The inlet and outlet ceramic honeycomb structures110,120may be submerged in the slurry to allow the slurry to infiltrate the inlet and outlet ceramic honeycomb structures110,120. More specifically, the slurry enters the flow channels114,124and permeates through at least a portion of the partition walls112,122, thereby depositing functional coating into pores of the partition walls112,122.

While specific mention is made above to inlet and outlet ceramic honeycomb structures110,120being made from a material adapted to adsorb CO2or being coated with a material adapted to adsorb CO2, it should be understood that the inlet and outlet ceramic honeycomb structures110,120may each be made using different materials and different manufacturing techniques that provide inlet and outlet ceramic honeycomb structures110,120that adsorb CO2.

It should also be understood that a variety of manufacturing methods may be employed to form ceramic honeycomb structures where more CO2adsorbing material is present at positions proximate to the fluid inlet104than at positions proximate to the fluid outlet106. Such manufacturing methods may include multiple washcoating processes to increase the CO2adsorbing material in local regions of the ceramic honeycomb structures, for example by increasing the thickness of the CO2adsorbent functional coating applied in the washcoating process. Further, rapid manufacturing techniques such as stereolithography, selective laser sintering, electron beam melting, 3D printing, or the like, may be used to form ceramic honeycomb structures having partition walls that vary in thickness and/or in orientation along their lengths. In some embodiments, the inlet and outlet ceramic honeycomb structures110,120may be discrete components. In other embodiments, the inlet and outlet ceramic honeycomb structures110,120may be continuous components that are affixed to one another or manufactured as an integral component. In general, manufacturing costs and/or difficulty of producing ceramic honeycomb structures increase with increasing adsorption of CO2. Accordingly, a reactor100that captures a desired quantity of CO2while incorporating outlet ceramic honeycomb structures120that are low cost may be desired.

As discussed hereinabove, a fluid stream containing CO2is introduced to the reactor100that includes the inlet ceramic honeycomb structure110and the outlet ceramic honeycomb structure120. The inlet and outlet ceramic honeycomb structures110,120adsorb the CO2from the fluid stream until becoming saturated with CO2. The point of saturation of the inlet and outlet ceramic honeycomb structures110,120progresses in the axial direction108until both of the inlet and outlet ceramic honeycomb structures110,120are saturated, at which point no additional CO2is adsorbed by the reactor, or until the fluid stream is diverted away from the reactor100.

When saturated with CO2, the inlet ceramic honeycomb structure110adsorbs an inlet quantity of CO2. Similarly, when saturated with CO2, the outlet ceramic honeycomb structure120adsorbs an outlet quantity of CO2. Reactors100incorporating inlet ceramic honeycomb structures110and outlet ceramic honeycomb structures120according to the present disclosure have inlet quantities that are greater than outlet quantities.

Referring now toFIG. 3, a diagrammatical representation of the saturation levels at increasing time is depicted of the reactor having inlet and outlet ceramic honeycomb structures110,120. With increasing time, the inlet and outlet ceramic honeycomb structures110,120adsorb an increasing amount of CO2from a fluid stream. The region of the inlet and/or outlet ceramic honeycomb structures110,120in which CO2is adsorbed is referred to herein as the “mass transfer zone.” The position of the mass transfer zone that is furthest from the fluid inlet104in the axial direction108is referred to herein as the “mass transfer point,” and is depicted as mass transfer points B1-B4inFIG. 3. A “breakthrough point” represents the mass transfer point (B4) as it reaches the end of the outlet ceramic honeycomb structure120proximate to the fluid outlet106. After the mass transfer point reaches the end of the outlet ceramic honeycomb structure120proximate to the fluid outlet106, CO2levels in the fluid stream measured at the fluid outlet106may be above the ambient levels of CO2.

At time t1, all of the CO2from the fluid stream is adsorbed within the inlet ceramic honeycomb structure110. At time t1, the mass transfer point B1is positioned within the inlet ceramic honeycomb structure110. The fluid stream continues to flow through the reactor100and continues to be adsorbed by the inlet ceramic honeycomb structure110. At time t2, the mass transfer point B2has traveled through the inlet ceramic honeycomb structure110into the outlet ceramic honeycomb structure120. At time t2, the outlet ceramic honeycomb structure120beings to adsorb CO2from the fluid stream in conjunction with the unsaturated portion of the inlet ceramic honeycomb structure110.

At time t3, the mass transfer point B3is positioned further into the outlet ceramic honeycomb structure120than at time t2. Note that at time t3, portions of the inlet ceramic honeycomb structure110positioned proximate to the fluid inlet104have approached saturation with CO2. These portions of the inlet ceramic honeycomb structure110, therefore, no longer are adsorbing CO2from the fluid stream. Correspondingly, addition portions of the outlet ceramic honeycomb structure120adsorb CO2from the fluid stream passing through the reactor100.

At time t4, the mass transfer point B4is positioned at and end of the outlet ceramic honeycomb structure120proximate to the fluid outlet106of the reactor. After time t4, as the inlet and outlet ceramic honeycomb structure110,120continue to approach saturation, the fluid stream exiting the reactor100beings to exhibit the presence of CO2. Time t4is referred to herein as the “breakthrough time,” or the time at which the mass transfer zone has traveled through the inlet and outlet ceramic honeycomb structures110,120, and the inlet and outlet ceramic honeycomb structures110,120can no longer adsorb all of the CO2in the fluid stream.

At time t5, portions of the outlet ceramic honeycomb structure120positioned proximate to the fluid inlet104continue to approach saturation. The inlet and outlet ceramic honeycomb structures110,120cannot adsorb all of the CO2from the fluid stream that flows through the reactor100, so the level of CO2in the fluid stream exiting the reactor100continues to increase. At time t6, all of the inlet and outlet ceramic honeycomb structures110,120have become saturated with CO2such that none of the inlet and outlet ceramic honeycomb structures110,120can adsorb CO2from the fluid stream. At time t6, the CO2concentration of the fluid stream entering the reactor100is substantially the same as the CO2concentration of the fluid stream exiting the reactor100.

The CO2concentration of the fluid stream evaluated at the fluid outlet106of the reactor100is schematically depicted inFIG. 4. As depicted, the CO2concentration of the fluid stream approaches zero for times t1through t4, as the inlet and outlet ceramic honeycomb structures110,120adsorb the CO2from the fluid stream in substantial portion. At time t4, the breakthrough time, the mass transfer point B4reaches the end of the outlet ceramic honeycomb structure120positioned proximate to the fluid outlet106of the reactor. After time t4, CO2concentration in the fluid stream exiting the reactor100beings to increase. The CO2concentration in the fluid stream continues to increase until time t6, at which point all of the inlet and outlet ceramic honeycomb structures110,120have become saturated with CO2, and the CO2concentration of the fluid stream entering the reactor100is substantially the same as the CO2concentration of the fluid stream exiting the reactor100.

The relative efficiency of adsorption of CO2from the fluid stream by the reactor may be gauged by the incline of the curve representing CO2concentration of the fluid stream measured as the fluid stream exits the reactor100. In general, the steeper the curve representing CO2concentration, the more efficient the use of material for adsorbing CO2in the reactor100. For example, compare the steepness of the curve representing the reactor100with a baseline reactor90having an equivalent quantity of CO2adsorbing material that is uniformly distributed along its length. The baseline reactor90has a breakthrough time t4that is earlier than the reactor100of the present disclosure. Thus, if the end-user application takes a reactor off-line at the breakthrough time t4, the reactor100of the present disclosure can stay on-line longer than the baseline reactor. In addition, still comparing reactor100to the baseline reactor90, time t6is closer to time t4for reactor100than for baseline reactor90. Similarly, the curve representing CO2concentration is steeper for reactor100than for baseline reactor90. Both a relatively smaller time between times t4and t6, along with a relatively steep curve representing CO2concentration may denote that the material for adsorbing CO2in the reactor100is being efficiently used, as a greater portion of the material can be saturated.

Referring now toFIG. 5, the velocity of the mass transfer point moving through the inlet and outlet ceramic honeycomb structures110,120of the reactor100for a constant mass flow rate of CO2is depicted. The inlet ceramic honeycomb structure110has an inlet mass transfer velocity118, and the outlet ceramic honeycomb structure120has an outlet mass transfer velocity128. Because the inlet ceramic honeycomb structure110has more CO2adsorbing material than the outlet ceramic honeycomb structure, the inlet ceramic honeycomb structure110adsorbs more CO2than the outlet ceramic honeycomb structure120. Accordingly, the mass transfer point moves less through the inlet ceramic honeycomb structure110than through the outlet ceramic honeycomb structure120. Thus, the inlet mass transfer velocity118is less than the outlet mass transfer velocity128.

While the discussion hereinabove has been directed to evaluating reactors100based on full saturation of the inlet and outlet ceramic honeycomb structures110,120, it should be understood that some end-user application may disable a reactor100at the breakthrough time t4, wherein breakthrough of the mass transfer zone occurs. Disabling a reactor100at such a time may prevent the fluid stream from containing significant concentrations of CO2after passing through the reactor. However, although the fluid stream does not fully saturate the inlet and outlet ceramic honeycomb structures110,120of the reactors100, efficiency of the reactors100can be evaluated according to the procedures discussed hereinabove with respect to fully saturating the inlet and outlet ceramic honeycomb structures110,120.

A reactor100according to the present disclosure that includes an inlet ceramic honeycomb structure110having more CO2adsorbing material than an outlet ceramic honeycomb structure120may adsorb more CO2than a comparable baseline reactor90that has a uniform distribution of the same quantity of CO2adsorbing material along the length of the baseline reactor90. The reactor100according to the present disclosure may adsorb an amount of CO2that is closer to the saturation amount of all of the ceramic honeycomb structures than the baseline reactor90. Restated, the reactor100according to the present disclosure may incorporate the same quantity of CO2adsorbing material in the baseline reactor90, but the reactor100according to the present disclosure may use the CO2adsorbing material more efficiently that the baseline reactor90.

Referring now toFIG. 6, another embodiment of the reactor200is depicted. Similar to the reactor100described with respect toFIG. 2hereinabove, the reactor200depicted inFIG. 6includes a reactor housing202having a fluid inlet204and a fluid outlet206positioned distally from the fluid inlet204. A fluid stream is introduced to the reactor200at the fluid inlet204and exits at the fluid outlet206. The reactor200includes an inlet ceramic honeycomb structure110positioned inside the reactor housing202at a position proximate to the fluid inlet204. The inlet ceramic honeycomb structure110includes a plurality of partition walls112extending in an axial direction108. The plurality of partition walls112form a plurality of flow channels114, similarly extending in the axial direction108. The partition walls112may be formed in an extrusion process, such that the flow channels114have approximately the same dimensions at all positions along the axial direction108. The inlet ceramic honeycomb structure110may also include a skin layer116surrounding the plurality of flow channels114. The skin layer116may be formed during the formation of the partition walls112or formed in later processing as an after-applied skin layer, such as applying skinning cement to the outer peripheral portion of the flow channels114.

The reactor200includes an outlet ceramic honeycomb structure120positioned inside the reactor housing202at a position proximate to the fluid outlet206. The outlet ceramic honeycomb structure120includes a plurality of partition walls122extending in the axial direction108. The plurality of partition walls122form a plurality of flow channels124, similarly extending in the axial direction108. Further, the outlet ceramic honeycomb structure120may include a skin layer126surrounding the plurality of flow channels124.

The reactor200includes a first intermediate ceramic honeycomb structure130positioned inside the reactor housing202at an axial position between the inlet ceramic honeycomb structure110and the outlet ceramic honeycomb structure120. The first intermediate ceramic honeycomb structure130includes a plurality of partition walls132extending in the axial direction108. The plurality of partition walls132form a plurality of flow channels134, similarly extending in the axial direction108. Further, the first intermediate ceramic honeycomb structure130may include a skin layer136surrounding the plurality of flow channels134.

The reactor200may also include a second intermediate ceramic honeycomb structure140positioned inside the reactor housing202at an axial position between the first intermediate ceramic honeycomb structure130and the outlet ceramic honeycomb structure120. The second intermediate ceramic honeycomb structure140includes a plurality of partition walls142extending in the axial direction108. The plurality of partition walls142form a plurality of flow channels144, similarly extending in the axial direction108. Further, the second intermediate ceramic honeycomb structure140may include a skin layer146surrounding the plurality of flow channels144.

Consistent with the inlet and outlet ceramic honeycomb structures110,120, the plurality of flow channels134,144of the first and second intermediate ceramic honeycomb structures130,140, respectively, may have a variety of shapes including having cross sections that are square, rectangular, round, oblong, triangular, octagonal, hexagonal, or combinations thereof. The flow channels134,144extend along the length of the first or second intermediate honeycomb structures130,140, such that a fluid stream introduced to the reactor100contacts the flow channels114,134,144,124along the length of the inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120.

In embodiments described herein, the inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120may be formed with a channel density of up to about 1600 channels per square inch (cpsi). For example, in some embodiments, the inlet and outlet ceramic honeycomb structures110,120may have a channel density in a range from about 100 cpsi to about 2000 cpsi. In some embodiments, the inlet, the first intermediate, the second intermediate, and the outlet ceramic honeycomb structures110,130,140,120may have different channel densities. For example, in one embodiment, the inlet ceramic honeycomb structure110may be formed with a channel density in a range from about 900 to about 2000 cpsi, the first intermediate ceramic honeycomb structure130may be formed with a channel density in a range from about 500 cpsi to about 1500 cpsi, the second intermediate ceramic honeycomb structure may be formed with a channel density in a range from about 200 to about 1000, and the outlet ceramic honeycomb structure120may be formed with a channel density in a range from about 100 to about 900 cpsi. As such, the amount of CO2adsorbing material in the inlet ceramic honeycomb structure110is greater than the amount of CO2adsorbing material in the first intermediate ceramic honeycomb structure130, which is greater than the amount of CO2adsorbing material in the second intermediate ceramic honeycomb structure140, which is greater than the amount of CO2adsorbing material in the outlet ceramic honeycomb structure120.

In addition, the inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120include a material that forms bonds with CO2, while allowing other components in the fluid stream to pass without bonding with the inlet first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120. In other embodiments, the material may be a functional coating that is applied onto the inlet first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120, which act as a substrate, positioning the functional coating within the reactor100as to capture CO2from the fluid stream. Examples of such materials that may be included in these applications are listed hereinabove.

When saturated with CO2, the inlet ceramic honeycomb structure110adsorbs an inlet quantity of CO2. When saturated with CO2, the first intermediate ceramic honeycomb structure130adsorbs a first intermediate quantity of CO2. When saturated with CO2, the second intermediate ceramic honeycomb structure140adsorbs a second intermediate quantity of CO2. When saturated with CO2, the outlet ceramic honeycomb structure120adsorbs an outlet quantity of CO2. Reactors100incorporating inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120according to the present disclosure have inlet quantities that are greater than first intermediate quantities, which are greater than second intermediate quantities, which are greater than outlet quantities.

The reactor200having inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120, as depicted inFIG. 6, operates with the same principles as discussed hereinabove in regard to the reactor100having inlet and outlet ceramic honeycomb structures110,120. The inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120sequentially adsorb CO2as the fluid stream passes from the fluid inlet204to the fluid outlet206. The inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120will each continue to adsorb CO2from the fluid stream until saturated with CO2.

The flow channels114,134,144,124of the inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120may be sized to provide the desired pressure drop for the fluid stream passing through the reactor. For example, the first inlet pressure drop of the inlet ceramic honeycomb structure110may be greater than the first intermediate pressure drop of the first intermediate ceramic honeycomb structure130, which may be greater than the second intermediate pressure drop of the second intermediate ceramic honeycomb structure140, which may be greater than the outlet pressure drop of the outlet ceramic honeycomb structure120.

Referring now toFIG. 7, the velocity of the mass transfer point moving through the inlet, first intermediate, second intermediate, and outlet ceramic honeycomb structures110,130,140,120of the reactor200for a constant mass flow rate of CO2is depicted. The inlet ceramic honeycomb structure110has an inlet mass transfer velocity118, the first intermediate ceramic honeycomb structure130has a first intermediate mass transfer velocity138, the second intermediate ceramic honeycomb structure140has a second intermediate mass transfer velocity148, and the outlet ceramic honeycomb structure120has an outlet mass transfer velocity128. The inlet, first intermediate, second intermediate, and outlet velocities118,138,148,128increase sequentially, because of a sequential reduction in CO2adsorbing material, corresponding to greater movement of the mass transfer zone through each of the ceramic honeycomb structures. Thus, the inlet mass transfer velocity118is less than the first intermediate mass transfer velocity138, which is less than the second intermediate mass transfer velocity148, which is less than the outlet mass transfer velocity128.

Computer-based modeling of the reactors100having a plurality of ceramic honeycomb structures has shown that controlling the distribution of CO2adsorbing material along the length of the reactor100. In one such computer model, a reactor100having three ceramic honeycomb structures, an inlet ceramic honeycomb structure110, a first intermediate honeycomb structure130, and an outlet ceramic honeycomb structure120was compared with a baseline reactor90having CO2adsorbing material uniformly distributed along the length of the ceramic honeycomb structure. All variables were held constant other than distribution of CO2adsorbing material within the ceramic honeycomb structures. The ceramic honeycomb structures were modeled as if made from a combination of zeolite type 13X and cordierite having a density of 1190 kg/m3. The ceramic honeycomb structure was modeled as if it had a length of 4 meters and a diameter of 1 meter. The fluid stream was modeled to operate at 50 bar pressure and a 10%-wt CO2concentration, with the balance natural gas, entering the fluid inlet of the reactor100. The reactor100according to the present disclosure included CO2adsorbing material that was 200% of the baseline reactor90over the inlet-side 40% of total length of the ceramic honeycomb structure, 50% of the baseline reactor90over the intermediate 30% of total length of the ceramic honeycomb structure, and 25% of the baseline reactor90over the outlet-side 30% of the total length of the ceramic honeycomb structure, such that the rector100according to the present disclosure had 2.5% greater CO2adsorbing material than the baseline reactor90.

The model was solved for isothermal conditions, and the rate of CO2adsorption was assumed to be constant with the percent of ceramic honeycomb structure saturation, such that the adsorption rate slows as the ceramic honeycomb structure approaches saturation. Modeling results illustrated that the reactor100according to the present disclosure exhibited a greater time before breakthrough of CO2at the fluid outlet of the reactor100as compared with the baseline reactor90, as well as greater breakthrough to complete saturation (seeFIG. 5), as compared with the baseline reactor90. Thus, modeling results indicate that the reactor100according to the present disclosure utilizes CO2adsorbing material more efficiently than a baseline reactor90that uniformly distributes the same amount of CO2adsorbing material.

While discussion hereinabove has been directed to reactors for adsorbing CO2 from a fluid stream, it should be understood that similar techniques may be applied to improve efficiency of selectively capturing other components from a fluid stream. Such other components may be captured by varying the active materials of the ceramic honeycomb structures.

It should be understood that reactors according to the present disclosure may incorporate any of a variety of number of ceramic honeycomb structures, depending on the requirements of a particular end-user application. Accordingly, some embodiments of reactors may have multiple ceramic honeycomb structures that have similar amounts of CO2adsorbing material, such that the amount of CO2adsorbed by at least two ceramic honeycomb structures within a reactor are the same, along with the velocity of the mass transfer point through at least two ceramic honeycomb structures.

A plurality of reactors100,200may be “ganged” together to suit the requirements of a particular end-user application. The fluid stream may be directed to pass through one of the plurality of reactors, which adsorbs CO2from the fluid stream. Simultaneously, the reactors to which the fluid stream is diverted away from may undergo a “degassing” operation, wherein CO2adsorbed by the reactor is desorbed from the CO2adsorbing material and flushed from the reactor. As reactors within the gang become saturated with CO2, the fluid stream may be diverted from the saturated reactors and directed into the unsaturated reactors. Thus, by ganging a plurality of reactors together, CO2can be captured from a fluid stream for an indefinite period of time.

It should now be understood that reactors according to the present disclosure allow for more efficient use of CO2adsorbing material by distributing the CO2adsorbing material non-uniformly along the axial length of the reactor. The ceramic honeycomb structures positioned inside the reactor housing can be selected to provide increased efficiency in adsorption of CO2, while managing costs associated with the reactor.

It should be understood that the present disclosure includes various aspects.

In a first aspect, the disclosure provides a reactor for adsorbing CO2from a fluid stream, the reactor comprising: a reactor housing comprising a fluid inlet and a fluid outlet; an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet, wherein: the inlet ceramic honeycomb structure has a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels; the inlet ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2, wherein the inlet ceramic honeycomb structure adsorbs an inlet quantity of CO2; and an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing, wherein: the outlet ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; the outlet ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2, wherein the outlet ceramic honeycomb structure adsorbs an outlet quantity of CO2, wherein the inlet quantity of CO2adsorbed by the inlet ceramic honeycomb structure is greater than the outlet quantity of CO2adsorbed by the outlet ceramic honeycomb structure.

In a second aspect, the disclosure provides a reactor for adsorbing CO2from a fluid stream, the reactor comprising: a reactor housing comprising a fluid inlet and a fluid outlet; an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet, wherein: the inlet ceramic honeycomb structure has a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels; the inlet ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2such that the inlet ceramic honeycomb structure has an inlet mass transfer velocity; and an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing, wherein: the outlet ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; and the outlet ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2such that the outlet ceramic honeycomb structure has an outlet mass transfer velocity, wherein, for a constant mass flow rate of a fluid stream containing CO2, the inlet mass transfer velocity is greater than the outlet mass transfer velocity.

In a third aspect, the disclosure provides a method of removing CO2from a fluid stream comprising: introducing the fluid stream to a reactor, wherein the reactor comprises a reactor housing having a fluid inlet and a fluid outlet, an inlet ceramic honeycomb structure positioned inside the reactor housing at a position proximate to the fluid inlet of the reactor housing, and an outlet ceramic honeycomb structure positioned inside the reactor housing at a position axially offset from the inlet ceramic honeycomb structure and proximate to the fluid outlet of the reactor housing, wherein the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure have a plurality of partition walls extending in an axial direction thereby forming a plurality of flow channels and comprise a material that forms bonds with CO2to adsorb the CO2, the inlet and outlet ceramic honeycomb structures comprise material that forms bonds with CO2to adsorb the CO2, the inlet and the outlet ceramic honeycomb structures are capable of adsorbing an inlet quantity and an outlet quantity of CO2, respectively, and the inlet quantity of CO2is greater than the outlet quantity of CO2; flowing the fluid stream from the fluid inlet to the fluid outlet of the reactor housing such that the fluid stream flows through the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure, wherein the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure have an affinity for CO2; sensing a chemical composition of a portion of the fluid stream flowing out of the fluid outlet of the reactor housing; and terminating the fluid stream from flowing into the reactor when CO2breakthrough is sensed.

In a fourth aspect, the disclosure provides the reactor of any of the first or third aspects further comprising a first intermediate ceramic honeycomb structure positioned inside the reactor housing at an axial position between the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure, wherein the first intermediate ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; the first intermediate ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2, wherein the first intermediate ceramic honeycomb structure adsorbs a first intermediate quantity of CO2, and the first intermediate quantity of CO2adsorbed by the first intermediate ceramic honeycomb structure is greater than the outlet quantity of CO2adsorbed by the outlet ceramic honeycomb structure and less than the inlet quantity of CO2adsorbed by the inlet ceramic honeycomb structure.

In a fifth aspect, the disclosure provides the reactor of the fourth aspect further comprising a second intermediate ceramic honeycomb structure positioned inside the reactor housing at an axial position between the first intermediate ceramic honeycomb structure and the outlet ceramic honeycomb structure, wherein the second intermediate ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; the second intermediate ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2, wherein the second intermediate ceramic honeycomb structure adsorbs a second intermediate quantity of CO2, and the second intermediate quantity of CO2adsorbed by the second intermediate ceramic honeycomb structure is greater than the outlet quantity of CO2adsorbed by the outlet ceramic honeycomb structure and less than the first intermediate quantity of CO2adsorbed by the first intermediate ceramic honeycomb structure.

In a sixth aspect, the disclosure provides the reactor of any of the first through fifth aspects, wherein the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure are discrete components.

In a seventh aspect, the disclosure provides the reactor of any of the first through fifth aspects, wherein the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure are continuous components.

In a seventh aspect, the disclosure provides the reactor of any of the first through seventh aspects, wherein an inlet pressure drop of the fluid stream passing through the inlet ceramic honeycomb structure is greater than an outlet pressure drop of the fluid stream passing through the outlet ceramic honeycomb structure.

In an eighth aspect, the disclosure provides the reactor of any of the fourth through seventh aspects, wherein an inlet pressure drop of the fluid stream passing through the inlet ceramic honeycomb structure is greater than an outlet pressure drop of the fluid stream passing through the outlet ceramic honeycomb structure, and a first intermediate pressure drop of the fluid stream passing through the first intermediate ceramic honeycomb structure is greater than the outlet pressure drop and less than the inlet pressure drop.

In a ninth aspect, the disclosure provides the reactor of any of the first through eighth aspects, wherein the inlet ceramic honeycomb structure comprises a first adsorbent material.

In a tenth aspect, the disclosure provides the reactor of any of the first through ninth aspects, wherein the outlet ceramic honeycomb structure comprises the first adsorbent material, and the outlet ceramic honeycomb structure has a lower saturation limit per unit volume than the inlet ceramic honeycomb structure.

In an eleventh aspect, the disclosure provides the reactor of any of the first through ninth aspects, wherein the outlet ceramic honeycomb structure comprises a second adsorbent material different than the first adsorbent material, and the second adsorbent material has a lower saturation limit per unit volume than the first adsorbent material.

In a twelfth aspect, the disclosure provides the reactor of any of the first through eleventh aspects, wherein the first adsorbent material is deposited on the plurality of partition walls of the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure as a functional coating, and a thickness of the functional coating on the inlet ceramic honeycomb structure is greater than a thickness of the functional coating on the outlet ceramic honeycomb structure.

In a thirteenth aspect, the disclosure provides the reactor of any of the first through twelfth aspects, wherein the plurality of partition walls of the inlet ceramic honeycomb structure have an inlet average minimum thickness, the plurality of partition walls of the outlet ceramic honeycomb structure have an outlet average minimum thickness, and the inlet average minimum thickness is greater than the outlet average minimum thickness.

In a fourteenth aspect, the disclosure provides the reactor of any of the first through thirteenth aspects, wherein the inlet ceramic honeycomb structure has an inlet cell density, the outlet ceramic honeycomb structure has an outlet cell density, and the inlet cell density is greater than the outlet cell density.

In a fifteenth aspect, the disclosure provides the reactor of any of the first through fourteenth aspects, wherein the plurality of partition walls of the inlet ceramic honeycomb structure have an inlet average minimum thickness, the plurality of partition walls of the outlet ceramic honeycomb structure have an outlet average minimum thickness, and the inlet average minimum thickness is less than the outlet average minimum thickness.

In a sixteenth aspect, the disclosure provides the reactor of the second aspect further comprising a first intermediate ceramic honeycomb structure positioned inside the reactor housing at an axial position between the inlet ceramic honeycomb structure and the outlet ceramic honeycomb structure, wherein the first intermediate ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; the first intermediate ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2such that the first intermediate ceramic honeycomb structure has a first intermediate mass transfer velocity, wherein for the constant mass flow rate of CO2, the first intermediate mass transfer velocity is greater than the inlet mass transfer velocity and less than the outlet mass transfer velocity.

In a seventeenth aspect, the disclosure provides the reactor of the sixteenth aspect further comprising a second intermediate ceramic honeycomb structure positioned inside the reactor housing at an axial position between the first intermediate ceramic honeycomb structure and the outlet ceramic honeycomb structure, wherein the second intermediate ceramic honeycomb structure has a plurality of partition walls extending in the axial direction thereby forming a plurality of flow channels; the second intermediate ceramic honeycomb structure comprises a material that forms bonds with CO2to adsorb the CO2such that the second intermediate ceramic honeycomb structure has a second intermediate mass transfer velocity, wherein the second intermediate mass transfer velocity is greater than the first intermediate mass transfer velocity and less than the outlet mass transfer velocity.