Modular Adsorbent Devices and Applications
An adsorbent device includes adsorbent fibers laid along or wound around a center tube. In a specific example, the adsorbent fibers are porous solid amine adsorbent fibers. A module for purifying a raw fluid includes one or more adsorbent devices that can be installed in a vessel in series or in parallel. The module can be configured for axial or cross flow operation and can be employed to purify a gas containing a contaminant such as an acid gas. In some implementations, the module is provided with one or more heating elements that can be used to release adsorbed contaminant to regenerate the adsorbent fibers.
This application claims the benefit under 35 USC 119(e) of: U.S. Provisional Application No. 63/220,739, filed on Jul. 12, 2021, U.S. Provisional Application No. 63/220,744, filed on Jul. 12, 2021, U.S. Provisional Application No. 63/220,734, filed Jul. 12, 2021, and U.S. Provisional Application No. 63/220,745, filed Jul. 12, 2021, all of which are incorporated herein by this reference in their entirety.
BACKGROUND OF THE INVENTIONCarbon capture, utilization and storage (CCUS) generally refers to various technologies believed to play an important role in meeting global energy and climate goals. For instance, these technologies are considered by many as essential in keeping global temperature increases below 1.5 degrees centigrade (° C.).
CCUS involves capturing CO2 from diluted gas streams, such as flue gas, air, etc. In the case of flue gas, the CO2 concentration is in the range of 8 to 14 volume %; in the case of ambient atmospheric air, the CO2 concentration is about 450 ppm. Currently, the upfront cost for CO2 capture from a variety of streams is more than 80% of the total CCUS costs. In the case of direct air capture, the upfront cost for CO2 capture is almost 99% of the total CCUS cost.
Conventional adsorbents usually come in beads or pellets, typically from 1 to 6 mm in diameter. Adsorbent beds that are packed with beads or pellets typically suffer from low bed packing, high pressure drop, and attrition. Structured sorbents like monoliths and fibers offer improvement over traditional bead or pellet packed bed structure, as discussed, for example, in Critical comparison of structured contactors or adsorption based gas separation, by S. J. A. DeWitt, A. Sinha, J. Kalyanaraman, F. Zhang, M. J. Realff, and R. P. Lively, Annu. Rev. Chem. Biomol. Eng., 2018, 9, page 129.
The review articles entitled Structured adsorbents in gas separation processes by F. Rezaei and P. Webley, Sep. Purif. Techn., 2010, 70, page 243 and Structuring adsorbents and catalysts by processing of porous powders by F. Akhtar, L. Andersson, S. Ogunwumi, N. Hedin, and L. Bergstrom, J. Eur. Ceram. Soc., 2014, 34, page 1643 summarize research efforts towards structured adsorbents. These references, however, do not offer any guidance regarding the construction of adsorbent device.
Current available adsorbent reactor configurations, such as fixed beds, moving beds, and fluidized beds, are summarized by C. Dhoke, A. Zaabout, S. Cloete, and S. Amin in the paper Review on reactor configurations for adsorption-based CO2 capture, Ind. Eng. Chem. Res., 2021, 60, page 3779.
U.S. Pat. Nos. 8,133,308, 8,257,474 and 8,377,172 disclose hollow fiber adsorbents formed from a dope containing a water insoluble polymer and a particular inorganic adsorbent. However, no information is offered regarding how the fibers might be packed and utilized for practical applications.
U.S. Pat. No. 9,446,349 discloses an adsorption and desorption device that encloses hollow fiber membrane adsorbents in a closed container equipped with a fluid inlet and a fluid outlet. Although the disclosed device can be utilized as a standalone device, it is unclear how the device can be scaled up and stacked for large scale industrial applications. This is also the case with US Patent Application No. 20120247330 and U.S. Pat. No. 8,911,536 which disclose an adsorption and desorption device formed by enclosing hollow fiber membrane adsorbents along with spacers in a closed container equipped with a fluid inlet and a fluid outlet.
An adsorption and desorption device formed by random or wound packing of adsorbent fibers is described in U.S. Pat. Nos. 9,713,787 and 10,464,009. These documents, however, do not provide information on how the packed device can be utilized in industrial applications.
Adsorbent loaded fibers are described in U.S. Pat. Nos. 10,525,399 and 10,525,400. US Patent Application Nos. 20210008523 and 20210031168 disclose methods for packing the fibers into a container. Although the disclosed device can be utilized as a standalone device, the device is difficult to scale up for large scale industrial applications. U.S. Pat. No. 9,878,291 describes a CO2 adsorption and regeneration system utilizing hollow fiber column. However, the hollow fiber column represents a standalone device which cannot be modulized and is difficult to scale.
U.S. Pat. No. 10,807,034 disclose an adsorbent canister containing sheet adsorbent materials.
SUMMARY OF THE INVENTIONAs evidenced by some of the references discussed above, a need continues to exist for purification methods and adsorbent equipment suitable for the removal or capture of acid gases. A need also exists for structured fiber adsorbent devices that can be scaled-up to meet industrial requirements in a cost-effective manner.
The invention generally relates to approaches for removing an impurity (also referred to herein as a “contaminant”), an acid gas, for instance, from a fluid stream.
In one of its aspects, the invention relates to a device (also referred to herein as an “adsorption device” or “cartridge”) that includes multiple (a plurality of, i.e., two or more) adsorbent fibers that are laid parallel to or wound, e.g., helically, around a center tube. The adsorbent fibers are made from a suitable adsorbent material. In an illustrative example, the adsorbent fibers are porous solid amine adsorbent fibers. The adsorbent fibers can be regenerated by desorbing trapped impurities using, for instance, heat, reduced pressure or vacuum or a combination thereof.
In a typical approach, the adsorbent fibers are formed in a fiber adsorbent arrangement, also referred to herein as a “fabric”, e.g., in a cylindrical shape, around the center tube. Epoxy tubesheets or threads can be used to seal the ends of the adsorbent fibers. In some embodiments, the fabric is partially wrapped in an impermeable sheet.
The center tube is hollow and provided with holes for fluid communication between the adsorbent fibers and the bore (lumen) of the center tube. The holes can be disposed along the length, at one of its ends, and so forth.
The device can be configured for longitudinal (axial) flow or cross (transverse) flow.
In another of its aspects, the invention features a process for removing a contaminant from a fluid stream containing the contaminant. In the process, a fluid stream is introduced at the shell or exterior side of the adsorbent fabric. As the stream passes through the fabric, at least a portion of the contaminant becomes adsorbed by the adsorbent fibers and a purified fluid stream is collected at the bore side of the center tube. A reversed arrangement (with the raw fluid stream being fed at the bore side of the center tube and a purified fluid stream being withdrawn at the shell side of the fabric) also can be employed.
In some embodiments, the fluid stream containing the contaminant travels through the fiber adsorbent arrangement in an axial direction. In others, it traverses the adsorbent fibers arrangement in a cross-flow pattern, e.g., in a direction perpendicular to the length of the center tube.
In a further aspect, the invention relates to a. system, also referred to herein as a “module”, that can include one or more adsorption devices such as described above, for example.
Various approaches can be used to construct or use a purification module containing one or more such adsorbent devices. In one embodiment, at least one adsorbent device is installed in a vessel which can be provided with an inlet, for introducing a fluid containing a contaminant (also referred to herein as a “raw” fluid) into the vessel, and an outlet, for collecting a purified (“clean”) fluid. In some implementations, the module includes multiple (at least two) adsorbent devices connected in series. In other embodiments, the system includes multiple adsorbent devices arranged in parallel. The system can include a heating element, for regenerating the adsorbent fibers, for instance. The heating element can be internal or external to the vessel. In an illustrative example, a heat exchanger is installed among several cartridges installed in a parallel configuration. In another, a vessel that includes adsorbent cartridges arranged in series is provided with a heating jacket.
During operation, raw fluid is introduced into the vessel and is brought into contact with the adsorbent fibers, which trap the contaminant, producing a purified fluid.
Thus, in yet another of its aspects, the invention features a process for removing a contaminant from a fluid containing the contaminant. The process involves directing the fluid into a module that contains at least one adsorbent cartridge including adsorbent fibers. The fluid stream is brought into contact with the adsorbent fibers, whereby at least a portion of the contaminant is adsorbed by the fibers, to produce a purified fluid which can be withdrawn (collected) from the module.
In one illustrative approach, the module contains two or more cartridges, arranged in series. In another, the module includes cartridges arranged in parallel.
The process can be designed for axial or cross flow pattern. In many cases, the fluid is introduced at the shell or exterior side of the adsorbent fabric and collected from the bore side of the center tube. A reversed flow configuration (with the raw fluid stream being fed at the bore side of the center tube and a purified fluid stream being withdrawn at the shell side of the fabric) also can be employed.
Adsorbent fibers can be regenerated by desorbing trapped impurities using, for instance, heat, reduced pressure, vacuum, or a combination thereof.
Cartridges, modules and methods described herein can be employed to remove contaminants, e.g., an acid gas such as CO2, H2S, SO2, from flue gases, biogases, hydrogen gas, natural gas, air or other fluid streams. Practicing the invention can be particularly well suited in handling low concentration separations, often resulting in high recoveries, less energy consumption, better economics, for example in direct air capture, removal of CO2 for LNG production, and CO2 capture from flue gases.
The device and/or system can be manufactured in various configurations, presenting many options for addressing specific needs. For instance, the module design can accommodate systems that rely on a single cartridge as well as systems in which multiple cartridges are connected in parallel or in series. Available options also include shell side as well as bore side feeding modes. The purification operation can be decoupled from recovering the adsorbed contaminant, CO2, for instance, adding flexibility to the overall process.
Providing an attractive alternative or supplementing membrane separation equipment, devices and/or systems described herein often include robust and rugged adsorbent fibers that can meet any number of process conditions, offering effective stream purification approaches at acceptable cost.
The above and other features of the invention including various details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings:
The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Also, all conjunctions used are to be understood in the most inclusive sense possible. Thus, the word “or” should be understood as having the definition of a logical “or” rather than that of a logical “exclusive or” unless the context clearly necessitates otherwise. Further, the singular forms and the articles “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms: includes, comprises, including and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Further, it will be understood that when an element, including component or subsystem, is referred to and/or shown as being connected or coupled to another element, it can be directly connected or coupled to the other element or intervening elements may be present.
It will be understood that although terms such as “first” and “second” are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, an element discussed below could be termed a second element, and similarly, a second element may be termed a first element without departing from the teachings of the present invention.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The invention generally relates to fluid purification equipment and techniques. The adsorption device (cartridge) described herein incorporates adsorbent fibers. One or more such devices can be assembled in a system (module). Further embodiments of the invention pertain to methods for preparing and/or using such adsorbent devices and/or modules.
Adsorbent devices that can be employed to prepare a module, for example, typically include multiple also referred to herein as a “plurality of” (i.e., at least two) adsorbent fibers disposed in various configurations (e.g., laid along to, typically in parallel, or wound around, e.g., helically) relative to a center tube.
In many cases, the adsorbent fibers form an arrangement also referred to herein as “bundle” or “fabric” around the center tube. The adsorbent fibers can be hollow adsorbent fibers. For many applications, however, non-hollow adsorbent fibers provide more adsorbing material for a given volume. In many embodiments, the fabric has a cylindrical shape. Its thickness may vary, depending on the type of cartridge, volume of gas treated or application. Typically, the fiber adsorbent arrangement has a thickness of at least about 1 inch, such as within a range of from about 1 inch to about 50 inches, preferably, from about 3 inches to about 20 inches.
The center tube can be a cylindrical hollow tube with openings (also referred to as holes, orifices or perforations) that allow fluid communication between an exterior (shell) surface of the fabric and the bore or lumen of the center (also referred to as “core”) tube. The center tube can be made from any nonimpermeable material that is compatible with the fluid streams being processed, e.g., metal, glass, wood, plastic, composite laminate, and the like. In an illustrative example, the center tube has a length within a range of from about 12 inches to about 100 inches and a diameter within a range of from about 0.5 inches to about 3 inches. The placement of the holes typically will depend on the kind of flow intended for the cartridge, as further described below.
Preparing an adsorbent fiber arrangement around the center tube often involves employing more than one fiber at the time, using, for instance, filaments of 4 to 32 fibers. Methods for laying or winding fibers in various configurations are known in the art, as described, for instance, in U.S. Pat. Nos. 5,837,033, 3,339,341 and 4,940,617, the contents of which are incorporated herein by this reference. Other approaches, e.g., those developed or refined in the future, also can be employed.
The fiber packing density can be controlled. With computerized winding techniques, for instance, the packing density can be precisely controlled using different winding parameters, such as winding angle, fiber spacing, phases, etc. This is described in U.S. Pat. No. 6,638,479, which is incorporated herein by this reference in its entirety.
The precision control of the fiber spacing offers the advantage of fast and uniform mass transfer. The pressure drop across a fiber adsorbent can be given as:
where L is the length, d is the cartridge diameter, ε is void fraction, and υ, μ are gas superficial velocity and viscosity, respectively. Equation 1 predicts that the pressure drop is a quadratic function of the interstitial velocity of the gas flow, and voidage.
The ends of the adsorbent fibers can be sealed with epoxy tube sheets. Techniques are described, for instance in U.S. Pat. Nos. 6,042,677, 6,290,756 and 6,709,494, which are incorporated herein in their entirety by this reference.
In some cases, e.g., if using computer controlled winding techniques to construct the device, threads can be used on one or both ends to hold the fiber tightly in place, as described, for example, in U.S. Pat. No. 6,638,479, which is incorporated herein in its entirety by this reference. Generally, these threads can provide a very effective seal for the fiber ends, rendering redundant epoxy sealing. Thus, in many implementations, the device uses epoxy sealing, or threads, or a combination of both.
In many embodiments of the invention, the complete device has a cylinder shape with the center tube extending outside the fiber arrangement. The ends of the center tube can be both in the same configuration or in a reciprocal configuration. In contrast to arrangements that employ hollow fiber membranes, contaminants such as acid gases are trapped or captured in the adsorbent material, which can be regenerated by cycling processes. Thus, the cartridge described herein does not need to provide for the extraction of a fluid fraction that is enriched with contaminant, as in the case of membrane separation devices.
The fiber arrangement can be covered (at least in part) with an impermeable wrap, with another type of covering or left uncovered. The choice depends, at least in part, on the flow configuration characterizing the cartridge.
Shown in
Holes 14 are disposed at one end of the center tube and can include a single or, typically, two or more (e.g., 4, 50, 100, 200, etc., depending on the center tube diameter and treated gas flow volume) perforations.
In the embodiment of
Wrap 24 partially encases fiber arrangement 16, being provided with wrap opening 26. Wrap 24 is made of an impermeable material, e.g., sheet plastic, metal, fiberglass, and so forth. In specific examples, the wrap material has a high thermal conductivity, such as, for instance, stainless steel sheet, copper sheet, etc. Materials characterized by high thermal conductivity can facilitate the heating of the adsorbents in systems in which a heat exchanger is placed outside of the cartridge.
As seen in
Other implementations, for cross flow operations, for instance, do not employ a wrap or simply use a highly porous cover, e.g., for protecting (from impact, dirt, etc.) the fiber arrangement. Examples of highly porous covers that can be employed include perforated sheets made of plastics, metals, and/or fiber glasses, woven or non-woven porous materials made of plastics, metals, and/or fiber glasses and so forth.
Ends 28 and 30 of the center tube (also referred to as “extension pieces” 28 and 30) reach outwardly, beyond the epoxy tubesheets 20 and 22. One or both ends 28 and 30 can be constructed into a “nozzle” by machining one or more o-ring groove(s) into the circumference of the extension piece. When inserted into a corresponding receptacle, o-rings sitting in these grooves ensure the formation of a tight seal for the fluid flows. Other means can be employed for connecting, e.g., in leak-tight fashion, the center tube to conduits for directing a fluid stream into or out of the cartridge.
Ends 28 and 30 can be configured in various ways, presenting a high degree of flexibility in meeting the demands of any number of applications. For example, if only one cartridge is employed in the purification process, or for systems that include multiple cartridges installed in parallel, one of the ends 28 and 30 can be blocked off by a solid cap or can be inserted into a receptacle that is not communicating with any other conduit. On the other hand, systems that include cartridges connected in series can rely on both ends for passing a fluid stream from one cartridge to the next.
In the embodiment of
A receptacle can be open or closed to fluid communication. In the case of employing a single cartridge or a system in which multiple cartridges are installed in parallel, one of the ends 28 and 30 can be blocked off by a closed-off receptacle (or a solid cap). Receptacles designed to be open to fluid flow can be used when connecting cartridges that are installed in series.
Shown in
While the embodiments of
As discussed in relation to
Shown in
A cross flow pattern also can be employed in some cases. Shown in
For many practical applications it is useful to assemble adsorbent devices such as those described with reference to
Shown in
In module 11, only one receptacle is configured for fluid communication. For example, receptacle 36 can provide a connecting port, specifically to an outlet for withdrawing a purified fluid from the vessel, while receptacle 38 lacks connection to an external port. In a different approach, end 30 is blocked, using a solid cap, for instance.
Optionally, one or more centering supports 25 (further described below) can be used to brace ends 28 and/or 30 during installation, to ensure, for instance, that the nozzle at the end of a cartridge properly engages with the corresponding receptacle.
Although a module containing a single adsorbent device can remove at least some contaminant is a fluid stream, such a module may not meet the demands of certain operations. For example, handling large volumes of raw fluid with a single adsorbent device in a module such as shown in
Vessels enclosing more than one cartridge can have any number of shapes or dimensions. Moreover, within a vessel, cartridges can be arranged in various configurations. Thus, designing a module may depend on the footprint available for the purification operation, flow volumes being handled, typical pressures encountered in a specific application, and/or other factors.
Some of the module designs can include vessel headers or manifolds for introducing and/or extracting fluids, for example. Others can use connecting elements (e.g., tubes, pipes, manifolds or other arrangements for directing fluids), supports (e.g., for bracing conduits or cartridges during installation or operation), spacers, and/or other components selected to provide improved mechanical stability, space optimization, synergies among module components, or other purposes.
As an illustration, arrangement 21 of
Tube coupling 23 can be secured (inside the vessel) using at least one centering support 25, as illustrated in
As already noted, adsorbent devices within the module can be arranged in various configurations.
Port 15 can be connected to exterior piping and can be used for feeding the raw fluid stream into the vessel. Module ends 47 and 49 include receptacles that can engage, respectively, with the nozzles of the first and last adsorbent cartridge. In the embodiment of
The cartridges are connected to one another using connecting elements such as described, for instance, with reference to
Some situations render long tube configurations impractical, however. Thus, other adsorbent cartridge arrangements can be used to meet space limitations. Shown in
For some large or extremely large flow applications (such as, for instance, the direct air CO2 capture or flue gas CO2 capture) the cartridges can be arranged in rows, to fit in a vessel or container with a rectangular (e.g., square) cross section. An example is presented in
Assemblies 61 and 81 illustrate adsorbent devices that are installed in a parallel configuration. Such configurations can be particularly well suited for situations in which the height or length of the available space is limited. Moreover, assemblies 61 or 81 can be fitted with common headers, manifolds and/or other piping arrangements for bringing in raw fluid to be distributed to each adsorbent cartridge. Clean fluid can be withdrawn from each cartridge and combined into a common output using manifolds, reservoirs and/or other suitable piping arrangements.
Cartridges and modules described herein can present additional options. Some relate to operations conducted to regenerate the adsorbent fibers that contain contaminant removed from the raw fluid.
Releasing the adsorbed contaminant, CO2, for instance, can be performed using heat, vacuum, reduced pressure, or any combination thereof. If the regeneration technique relies on heat, the desorption process can be a temperature swing adsorption (TSA) method, while many processes based on lowered pressures are known as pressure swing adsorptions (PSA). Another useful technique that can be employed to release adsorbed species, e.g., from the porous solid amine adsorbents further described below involves both heating and vacuum, the process being known as temperature-vacuum swing adsorption or TVSA. These techniques are well known in the art (see, e.g., U.S. Pat. Nos. 9,457,340, and 8,974,577, the entire contents of both being incorporated herein by this reference).
If TSA or TVSA techniques are employed, a module such as described in the present application can be provided with one or more heating element(s) that can be used to raise the temperature of the adsorbent fibers, thereby releasing the trapped contaminant and regenerating the fibers. Example of heating elements include but are not limited to heating tapes, heating coils, heating jackets, heat exchanging pipes, heat exchanging plates and so forth.
In some cases, the heating element is external to the vessel containing the adsorbent cartridge(s). Shown in
One or more heating elements also can be installed in the interior of (within) the vessel containing the cartridges. For example, a heating jacket, heating coils, heating plates, heating tape, etc. can be installed at an interior surface the vessel. To speed up the heating/cooling operation, one or more heating elements can be installed in between, around, among, etc. cartridges present within the module. In some cases, a cartridge may be individually wrapped or contacted by a heating element. In others, some or all cartridges present can share a heating element.
Shown in
Heat exchanger fluid can enter or exit the heat exchanger via ports 145 (
In some embodiments, steam (which is widely available and can represent an inexpensive source of heat) is directed into the module to recover the adsorbed contaminant, CO2, for instance.
Temperatures, pressures and/or other parameters relevant to the adsorption or desorption stage can be monitored or controlled using techniques and devices known in the art. Adjustments can be made by an operator, for example. In automated processes, conditions and parameters can be computer controlled.
The module embodiments described herein offer wide operational flexibility. Raw fluid, for example, can be ted at the shell or at the bore side of the cartridges. The fluid flow in the module can be configured for an axial or cross flow pattern. Series or parallel assemblies can address specific needs.
As one example,
If desired, a reversed configuration with bore side feeding and shell side collection can be implemented as well, without a negative on the adsorption. It is also possible to operate a module with cartridges linked in series in cross flow mode. For example, cartridges 50 in
Shown in
During operation, the raw fluid enters vessel 203 through inlet port 15 and is distributed to the shell side of cartridges 50 through wrap opening 26. With end 28 of each cartridge being closed, e.g., using cap 209, the fluid travels through the adsorbent fabric along (e.g., parallel to) the center tube. At least a portion of the contaminant becomes trapped by the adsorbent fibers and a purified (clean) fluid passes from the adsorbent fabric into the interior of each center tube via holes 14 (
Module 201 can be operated in a reverse manner, with bore side feeding and shell side collection without an adverse effect on the adsorption.
In
A group of adsorbent devices 50 is heated by heat exchangers 43. Heat exchanger fluid enters the module via inlet conduit 305, is distributed to heat exchangers 43 via header 307 and exits vessel 303 via outlet conduit 309.
Raw fluid is introduced to vessel 303 via inlet conduit 15 and enters each cartridge 50, from the shell side, via wrap opening 26. With end 28 capped (using cap 209, for example), raw fluid proceeds through the adsorbent fabrics along the center tubes, in an axial flow pattern essentially as described above. Clean fluid exits the fabrics, passes to the lumen of the center tubes via holes 14 (
In a different approach, individual output streams from ends 30 of cartridges 50 exit the module through individual ports and can be combined outside the vessel. A reversed input-output configuration, with raw fluid being fed from the bore side of each individual cartridge, and purified fluid being collected at the shell side of the cartridges can be implemented without a detrimental effect on the adsorption.
For cross flow operation, cartridges 50 in module 201 or 301 can be replaced with cartridges designed for cross flow, as described with reference to
More than one module can be employed, to meet the requirements of a specific application, for instance.
In contrast to modular arrangements that employ hollow fiber membranes, contaminants such as acid gases are trapped or captured in the adsorbent material, which can be regenerated by cycling processes. Thus, the module designs described herein do not need to provide for the extraction of a fluid fraction that is enriched with contaminant, as in the case of membrane separation systems.
The adsorbent fibers employed in the modules described herein can be formed using any suitable adsorbent material. Examples include zeolites, MOFs, COFs, PAFs active carbon and others. In some cases, the adsorbing material is dispersed in a porous polymer matrix, as described, for instance, in U.S. Pat. Nos. 10,525,399 and 10,525,400; and U.S. Patent Application Publication Nos. 20210008523 and 20210031168. The contents of these documents are incorporated herein by reference in their entirety.
In an illustrative implementation, the adsorption device and/or the module include(s) a porous solid amine adsorbent that is particularly well suited for the removal of an acid gas from contaminated fluid streams. Such an adsorbent is described in U.S. Provisional Application Nos. 63/220,734 and 63/220,745, both filed on Jul. 12, 2021, in U.S. Non-Provisional Patent Application filed concurrently herewith, under Attorney Docket No. 0413.0004US1, and the International Patent Application, filed concurrently herewith under Attorney Docket No. 0413.0004WO1, the entire contents of these documents being incorporated herein by this reference. As seen in these documents, porous solid amine adsorbents, typically robust and self-supporting, can be prepared by contacting a first solution with a second solution.
Among the constituents of the first solution is an amine-containing compound (a substance that includes functional groups such as —NH2, —RNH, or —RR′N), and another polymer.
In specific embodiment, the amine-containing compound is a water-soluble amine-containing polymer. As used herein, the term “amine-containing polymer” or “amine polymer” refers to polymers that contain —NH2, —RNH, or —RR′N functional groups attached to/separated by —CH2CH2—, —CH2CH2CH2—, or —CH2CH2CH2CH2—. The R and R′ groups can be methyl, ethyl, propyl, etc. groups and can be the same or different.
The water-soluble amine polymer can be provided in a wide range of molecular weights, from about 400 to about 10,000,000, for example. Some implementations utilize a water-soluble amine polymer within a range of from about 1,000 to about 1,000,000.
In one example, the water-soluble amine compound (e.g., polymer) includes a unit skeletal structure represented by Formula 1:
—[(CH2)x—NR]y— (1)
In the unit skeletal structure, R may be hydrogen or a branched chain; x is an integer of 1 to 4, and y is an integer of 2 to 1,000,000. In specific implementations, the amine compound is a linear or branched polyethylenimine (for x=2) or a linear or branched polypropylenimine (for x=3).
In another example, the water-soluble amine compound (e.g., polymer) includes a structure represented by Formula 2:
—[(CH2)x—CH(NH2)]y— (2)
where x is an integer of 1 to 4 and y is an integer of 2 to 1,000,000. In specific implementations, the amine compound represented by Formula 2 is a polyvinylamine (in the case of x=1).
The amount of the water-soluble amine compound can be within a range of from about 5 to about 50% based on the total weight of the first (e.g., dope) solution.
The first solution also includes another constituent, typically a water insoluble polymer. The water insoluble polymer forms a porous polymeric structure upon contact with a solvent such as water, providing a mechanical support for the porous solid amines formed from the reaction with a multifunctional acid. In the absence of a water insoluble polymer, the porous solid amine adsorbent will be sticky and difficult to shape into a desired configuration.
Water insoluble polymers that can be utilized to prepare the first solution can be natural or synthetic. Examples of natural polymers include lignin, cellulose, cellulose derivatives, (such as cellulose acetates, for instance), and others. Examples of synthetic polymers include polyacrylonitrile, poly(methyl methacrylate), polystyrene, polyethylene terephthalate), aromatic polyamides, aliphatic polyamides, polyesters, polyetherketones, polyethersulfones, polyetheresters, polysulfones, polyvinyl fluoride, polybenzimidazoles, polybenzoxazoles, polyazoaraomatics, poly(2,6-dimethylphenylene oxide), polyphenylene oxides, polyureas, polyurethanes, polyhydrazides, polyazomethines, polyacetals, polyquinoxaline, polyamideesters, polyacetylenes, polymer with intrinsic porosities (PIMs), polyesters, any combinations (blends) or copolymers thereof.
Many embodiments of the invention utilize water insoluble polymers that exhibit a glass transition temperature or a melting point above 100° C. Advantageously, such polymers are expected to withstand temperatures employed during the thermal regeneration of the adsorbent, without a significant pore collapse.
The amount of water-insoluble polymer in the first solution can be within a range of from about 5 to about 50 weight %.
The first solution can be prepared by combining the water insoluble polymer and the water-soluble amine polymer in a polar solvent. In many implementations, the polar solvent is an organic liquid that is miscible with water. It can dissolve the amine polymer as well as the water-insoluble polymer. Examples include but are not limited to ethanol, propanol, n-butanol, tetrahydrofuran (THF), dimethylformamide (DMF), dimethylacetamide (DMAc or DMA), dimethylsulfoxide (DMSO), N-methyl pyrrolidone (NMP), or mixtures thereof. Other polar solvents can be employed.
The polar solvent can be present in the first solution in an amount within a range of from about 50 to about 90 wt %.
The first solution can be a homogeneous solution in which all three components, namely the water-insoluble polymer, the water-soluble amine polymer and the polar solvent, are miscible.
The first solution can include other ingredients such as, for instance, a non-solvent component and/or a particulate material.
In one typical implementation, the second solution is an aqueous solution containing a multivalent (multifunctional) acid, i.e., an acid having two or more acid functional groups. In another typical implementation, the second solution is an aqueous solution containing a multivalent metal ion, such as Ca2+, Cu2+, Zn2+, and Me2+.
The aqueous solution can include water in an amount of at least 80% based on the total weight of the aqueous solution, preferably in an amount that is equal or greater than 95 wt %.
The multifunctional acid can be an inorganic acid, such as sulfuric acid or phosphoric acid, or an organic acid. Examples of suitable multifunctional organic acids (having two or more —COOH groups) include oxalic acid, citric acid, malic acid, tartaric acid, humic acid, dithiodipropionic acid, succinic acid, sulfosuccinic acid, phytic acid, trans aconitic acid, polyacrylic acid and its copolymers, polyvinylphosphonic acid and its copolymers, polystyrene sulfonic acid and its copolymers, polystyrene phosphonic acid and its copolymers, polystyrene carboxylic acid and its copolymers, and the like, or any mixtures thereof.
In one example, the acid concentration in the aqueous solution is in the range of 0.01% to 30%, preferably in the range of 0.1% to 10% relative to the total weight of the aqueous solution.
In some cases, the second solution is simply an acid-water solution. In others, the second solution further includes one or more additive(s).
Porous solid amine adsorbents are prepared by bringing together the two solutions. In many cases the product is formed rapidly, e.g., in a matter of seconds.
Porous solid amine adsorbents also can be prepared by contacting a first (dope) solution such as described above with a second solution that contains a metal ion (Cu2+, for instance) that can form a multiligand metal complex. The metal ion can be a component in a multifunctional metal salt. Procedures are described in U.S. Provisional Application No. 63/220,745, filed on Jul. 12, 2021, U.S. Non-Provisional Patent Application filed concurrently herewith, under Attorney Docket No. 0413.0004US1, and International Patent Application, filed concurrently herewith under Attorney Docket No. 0413.0004WO1, the entire contents of these documents being incorporated herein by this reference.
Without wishing to be bound by any particular theory or interpretation, it is believed that once the first solution (e.g., dope) is brought into contact with the aqueous solution containing a multifunctional chemical agent (e.g., a multifunctional acid or metal salt), the water insoluble polymer chain is frozen into solid state by a non-solvent induced phase inversion, while the water soluble amine compound is frozen into solid state by a rapid crosslinking reaction between at least some of the amine functional groups and the multifunctional chemical agent. It is further believed that without the multifunctional chemical agent, the water-soluble amine compound would become rapidly diffused into the water solvent precluding the formation of a functional adsorbent.
The porous solid amine adsorbent can be fabricated in various forms including fibers, hollow fibers and others. To form a (non-hollow) porous solid fiber, for example, the first (dope) solution (containing a water insoluble polymer and a water soluble amine polymer) can be extruded through a needle, passed through air, then brought into contact with the second solution (namely the aqueous solution containing a multifunctional acid). Techniques that can be followed or adapted are described, for example, in U.S. Pat. No. 5,181,940, except that no bore fluid is utilized.
In illustrative examples, the porous solid amine adsorbents are fabricated in fibers (which can be hollow or non-hollow fibers) having any desired outer diameters, e.g., within a range of from about 5 mil to about 50 mil. Other properties characterizing the fibers prepared as described herein (such as, for instance, a surface porosity that can be in the range of 1% to 60% by area) can be obtained by selecting or adjusting the equipment design, the process conditions or other factors.
The porous solid amine adsorbents, e.g., in the shape of fibers, can be further processed. In an optional step, for example, the porous solid amine adsorbents can be washed with water, alcohol or another suitable washing medium, e.g., to remove the solvent as completely as possible.
The porous solid adsorbent obtained by contacting the first and second solution, optionally washed, can be dried under ambient conditions or in an oven, e.g., at temperatures such as from 50° C. to 100° C. In some cases, heat treatment (in a suitable oven, for instance) can be undertaken, e.g., to impart desired mechanical properties to the product adsorbent.
In some embodiments, the adsorption device or the module is employed to remove an acid gas contaminant (CO2, H2S, SO2, for instance) from a fluid stream such as flue gases, biogas, hydrogen gas, natural gas or air. The acid gas released from the adsorbent fibers can be stored or used in other applications. For example, the carbon dioxide desorbed from the fibers employed in the cartridge can be utilized for enhanced oil recovery, to prepare synthetic fuels, such as methanol, methane, jet fuels, etc. In some embodiments, the carbon dioxide is injected for storage.
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
Claims
1. A fluid purification system, the system comprising:
- a vessel provided with an inlet for introducing a fluid to be purified and an outlet for collecting purified fluid;
- at least one adsorbent device within the vessel, the at least one adsorbent device comprising multiple adsorbent fibers; and
- an optional heating element at the exterior or in the interior of the vessel.
2. The fluid purification system of claim 1, wherein the adsorbent fibers are disposed along a length of or wound around a hollow center tube, forming a fiber arrangement, fluid communication between a shell side of the fiber arrangement and an interior space of the center tube being through one or more openings defined in the hollow center tube.
3. The fluid purification system of claim 1, further comprising one or more receptacles for engaging the at least one adsorbent device.
4. The fluid purification system of claim 1, wherein the vessel includes multiple adsorbent devices connected in series.
5. The fluid purification system of claim 1, wherein the vessel includes multiple adsorbent devices arranged in a parallel configuration.
6. The fluid purification system of claim 1, wherein the optional heating element is a heating jacket or a heat exchanger.
7. The fluid purification system of claim 1, wherein the fluid purification system is configured for axial flow or wherein the fluid purification system is configured for cross flow.
8. The fluid purification system of claim 1, wherein the fluid purification system is configured for shell side feeding, or wherein the fluid purification system is configured for bore side feeding.
9. The fluid purification system of claim 1, wherein the multiple adsorbent fibers form a fiber arrangement having an exterior surface.
10. The fluid purification system of claim 9, wherein the exterior surface of the fiber arrangement is partially wrapped by an impermeable stainless steel sheet, a copper sheet or a fiberglass sheet.
11. The fluid purification system of claim 9, wherein the exterior surface of the fiber arrangement is not covered or covered by a perforated plastic material.
12. The fluid purification system of claim 1, wherein the adsorbent fibers include a zeolite, activated carbon, MOF, COF or PAF material, or wherein the adsorbent fibers include linear polyethylenimine, branched polyethylenimine and polyvinylamine, or wherein the adsorbent fibers include a crosslinked linear polyethylenimine, crosslinked branched polyethylenimine and crosslinked polyvinylamine, or wherein the adsorbent fibers include a porous solid amine adsorbent in which an amine-containing polymer is embedded in a polymeric matrix.
13. A process for removing a contaminant from a fluid stream containing the contaminant, the process comprising:
- directing the fluid stream to a module containing at least one adsorbent device, wherein the adsorbent device includes adsorbent fibers;
- bringing the fluid stream in contact with the adsorbent fibers, whereby at least a portion of the contaminant is adsorbed by the adsorbent fibers to produce a purified fluid stream; and
- collecting the purified fluid stream from the module.
14. The process of claim 13, further comprising regenerating the adsorbent fibers.
15. The process of claim 13, further comprising desorbing the at least a portion of the contaminant from the adsorbent fibers by heat, reduced pressure, vacuum, or a combination of heat and reduced pressure or vacuum, thereby regenerating the adsorbent fibers.
16. The process of claim 13, wherein the adsorbent fibers are disposed along a length of or wound around a hollow center tube, forming an adsorbent arrangement, fluid communication between a shell side of the adsorbent arrangement and an interior space of the hollow center tube being through one or more openings defined in the center tube.
17. The process of claim 13, wherein the module includes multiple adsorbent devices arranged in series or wherein the module includes multiple adsorbent devices arranged in a parallel configuration.
18. The process of claim 13, wherein the process is configured for axial flow or wherein the process is configured for cross flow.
19. The process of claim 13, wherein the process is configured for shell side feeding or wherein the process is configured for bore side feeding.
20. The process of claim 13, wherein the fluid stream containing the contaminant is a flue gas, a biogas, hydrogen gas, natural gas or air, or wherein the contaminant is carbon dioxide, hydrogen sulfide or sulfur oxide.
21. The process of claim 13, wherein the adsorbent fibers include a material selected from the group consisting of zeolites, activated carbons MOFs, COFs and PAFs, or wherein the adsorbent fibers include linear polyethylenimine, branched polyethylenimine and polyvinylamine, or wherein the adsorbent fibers include a crosslinked linear polyethylenimine, crosslinked branched polyethylenimine and crosslinked polyvinylamine, or wherein the adsorbent fibers include a porous solid amine adsorbent in which an amine-containing polymer is embedded in a polymeric matrix.
22. A fluid purification device, the device comprising:
- a plurality of adsorbent fibers disposed along a length of a center tube or wound around the center tube, wherein:
- the center tube is hollow; and
- fluid communication between a shell side of the plurality of adsorbent fibers and an interior space of the center tube is through one or more openings defined in the center tube.
Type: Application
Filed: Jul 7, 2022
Publication Date: Jan 12, 2023
Inventor: Yong Ding (Waban, MA)
Application Number: 17/859,121