MBZA / PEG ether-based liquid solvent CO2 capture in a rotating packed bed

Abstract

The present disclosure provides an apparatus for removing acid gas components from a gas stream, and related systems and methods. The present disclosure provides a rotating packed bed (RPB)-based absorber having a non-aqueous liquid solvent contained therein for treating a gas stream, wherein the non-aqueous liquid solvent captures acidic components from the gas stream. Using the apparatus, systems, and methods described herein, various advantages can be achieved, such as with respect to space considerations and associated costs.

Description

[0001] FIELD OF THE DISCLOSURE

[0002] The present invention relates to systems for removing specific components of a gas stream, and methods of using such systems. More specifically, the present invention can provide for the removal of acid gases such as CO2, SO2, COS, CS2, and NOx.

[0003] background

[0004] The combustion of fossil fuels such as coal, oil, and natural gas is expected to remain the primary global energy source for years to come. Currently, 65% of global greenhouse gas emissions come from fossil fuel-fired power plants, and the use of fossil fuel power plants is expected to increase by as much as 28% by 2040 due to significant growth in emerging markets, including China and India. The environmental impact of anthropogenic carbon dioxide (CO2) emissions has prompted worldwide efforts to reduce atmospheric releases of CO2. Carbon capture and sequestration (CCS) technology has advanced over the past decade and has become one of the most promising solutions for reducing CO2 (and other acid gases) emissions.

[0005] The most advanced carbon capture and storage technology to date is amine-based solvent scrubbing. Solvent-based CO2 capture systems have high CO2 capacity, reversible reactivity with CO2, low heat requirements for absorption and regeneration, and can be composed of aqueous or non-aqueous components. The monoethanolamine (MEA) solvent process has been the most rigorously studied CCS system and has become the first commercial-scale demonstration CCS process at SaskPower's Boundary Dam power plant in Saskatchewan, Canada, capturing up to 1.3 million tons of CO2 per year.

[0006] This type of treatment system is typically associated with high capital and operating expenses, which limits their widespread implementation, and over the past decade, most research has focused on reducing the energy requirements for regeneration of the capture solvents used for CO2 removal to improve these deficiencies. With increasing regulations on CO2 emissions and the desire to reduce the cost of CO2 removal via CCS technology, it would be advantageous to provide alternative systems for treating CO2-containing gases to reduce atmospheric releases of CO2.

[0007] Brief Overview

[0008] The present disclosure provides apparatus and related systems for removing acid gases, such as CO 2 , from gas streams, and methods of removing acid gases using such apparatus or systems.

[0009] In one aspect of the present disclosure, an apparatus for removing one or more acidic gas components from a gas stream is provided, the apparatus comprising a rotating packed bed (RPB) arranged on a rotatable shaft, the RPB comprising: a gas inlet through which influent gas can enter for gas-liquid contact; a gas outlet through which effluent gas can exit after gas-liquid contact; a liquid inlet through which liquid can enter for gas-liquid contact; a liquid outlet through which liquid can exit after gas-liquid contact; and a conduit between the liquid inlet and the liquid outlet, the conduit comprising a non-aqueous liquid solvent for gas-liquid contact contained therein, wherein the non-aqueous liquid solvent comprises approximately 18% or less water by weight.

[0010] The characteristics of the non-aqueous liquid solvent can vary. In one embodiment, the non-aqueous liquid solvent is a solvent for removing acid gases from a flue gas stream. In one embodiment, the non-aqueous liquid solvent has a solubility in water of less than about 25 g water / 100 g non-aqueous liquid solvent (e.g., about 1 g water / 100 g non-aqueous liquid solvent to about 25 g water / 100 g non-aqueous liquid solvent, or about 2 g water / 100 g non-aqueous liquid solvent to about 25 g water / 100 g non-aqueous liquid solvent). In other embodiments, the non-aqueous liquid solvent comprises about 15% or less water by weight, 12% or less water by weight, 10% or less water by weight, or less than 10% water by weight. In some embodiments, the non-aqueous liquid solvent has a kGa value of about 4 or greater or about 4.5 or greater (e.g., including but not limited to about 4 to about 8, about 4.5 to about 8, about 4 to about 7, or about 4.5 to about 7), for example, for an L / G ratio above 0.45 kg / kg (e.g., for an L / G ratio of 0.45 kg / kg to 10 kg / kg or about 0.45 kg / kg to 8 kg / kg). In one embodiment, the non-aqueous liquid solvent has a kGa value of about 4 to about 8 for an L / G ratio of 0.45 kg / kg to 10 kg / kg.

[0011] In one embodiment, the non-aqueous liquid solvent includes a physical absorbent and / or a chemical absorbent. For example, in certain embodiments, the non-aqueous liquid solvent includes one or more hydrophobic primary amines and / or one or more hydrophobic secondary amines. In certain embodiments, the non-aqueous liquid solvent includes one or more diluents, the diluent being selected from the group consisting of the following items: optionally substituted alcohols, optionally substituted phenols, optionally substituted nitrogen heterocycles, optionally substituted aliphatic hydrocarbons, optionally substituted ketones, optionally substituted aliphatic ethers, optionally substituted cyclic ethers, optionally substituted oxygen heterocycles, optionally substituted nitrogen heterocycles, optionally substituted esters, optionally substituted amides and mixtures thereof. In one embodiment, the non-aqueous liquid solvent includes hydrophobic primary amines or hydrophobic secondary amines and a diluent, the diluent including optionally substituted aliphatic ethers. In other embodiments, the non-aqueous liquid solvent includes an ionic liquid.

[0012] The characteristics of the RPB can vary. Various RPB configurations are known and can be employed in accordance with various embodiments of the present disclosure. In some embodiments, the temperature and / or pressure within the RPB can be controlled. In one embodiment, the RPB is equipped with a cooling mechanism (e.g., intermediate cooling of the RPB or between stages) and / or a heating mechanism. In some embodiments, a second RPB is in fluid communication with the RPB, for example, such that the cooling mechanism is between the RPB and the second RPB.

[0013] The present disclosure also provides a system for removing one or more acid gas components from a gas stream, the system comprising an apparatus as provided herein. In one embodiment, the system further comprises a regenerator in fluid communication with the liquid outlet. In some embodiments, the regenerator may comprise a second RPB.

[0014] In another aspect of the present disclosure, a method for treating a gas stream to remove one or more acid gas components therefrom is provided, the method comprising passing the gas stream into a gas inlet of an apparatus or system as described herein. The source and composition of the gas stream may vary. In one embodiment, the gas stream is a flue gas stream. In some embodiments, the acid gas components include carbon dioxide (CO2), carbonyl sulfide (COS), carbon disulfide (CS2), and sulfur oxides (SO x , for example, SO 2 ) In some embodiments, the acid gas component specifically includes CO 2 . In some embodiments, the method further comprises regenerating the non-aqueous liquid solvent to remove the acid gas component therefrom.

[0015] The present disclosure also provides a method of reducing capital and operating expenses associated with a system designed to capture acid gas components from a gas stream, the method comprising employing an apparatus as described herein in the system in place of a conventional packed column bed absorber apparatus.

[0016] The present disclosure includes, but is not limited to, the following embodiments.

[0017] Embodiment 1: An apparatus for removing one or more acidic gas components from a gas stream, comprising a rotating packed bed (RPB) arranged on a rotatable shaft, the RPB comprising: a gas inlet through which an influent gas can enter for gas-liquid contact; a gas outlet through which an effluent gas can exit after gas-liquid contact; a liquid inlet through which a liquid can enter for gas-liquid contact; a liquid outlet through which the liquid can exit after gas-liquid contact; and a conduit between the liquid inlet and the liquid outlet, the conduit comprising a non-aqueous liquid solvent for gas-liquid contact contained therein, wherein the non-aqueous liquid solvent comprises approximately 18% or less water by weight.

[0018] Embodiment 2: The apparatus of Embodiment 1, wherein the non-aqueous liquid solvent is a solvent for removing acid gases from a flue gas stream.

[0019] Embodiment 3: The apparatus of any one of Embodiments 1-2, wherein the non-aqueous liquid solvent has a solubility in water of less than about 25 g water per 100 g non-aqueous liquid solvent.

[0020] Embodiment 4: The apparatus of any one of Embodiments 1-3, wherein the non-aqueous liquid solvent comprises less than 15% by weight water or less than 10% by weight water.

[0021] Embodiment 5: The apparatus of any one of Embodiments 1-4, wherein the non-aqueous liquid solvent comprises from about 2% to about 10% water by weight.

[0022] Embodiment 6: The apparatus of any one of Embodiments 1-5, wherein the non-aqueous liquid solvent has a kGa value of about 4 or greater for L / G ratios above 0.45 kg / kg.

[0023] Embodiment 7: The apparatus of Embodiment 6, wherein the non-aqueous liquid solvent has a kGa value of about 4 to about 8 for an L / G ratio of 0.45 kg / kg to 10 kg / kg.

[0024] Embodiment 8: The apparatus of any one of Embodiments 1-7, wherein the non-aqueous liquid solvent comprises a physical absorbent, a chemical absorbent, or both a physical absorbent and a chemical absorbent.

[0025] Embodiment 9: The apparatus of any one of Embodiments 1-8, wherein the non-aqueous liquid solvent comprises one or more hydrophobic primary amines and / or one or more hydrophobic secondary amines.

[0026] Embodiment 10: The apparatus of any one of Embodiments 1-9, wherein the non-aqueous liquid solvent comprises from about 40% to about 80% by weight of the one or more primary hydrophobic amines and / or the one or more secondary hydrophobic amines.

[0027] Embodiment 11: The apparatus of any one of Embodiments 1-10, wherein the non-aqueous liquid solvent comprises one or more diluents selected from the group consisting of optionally substituted alcohols, optionally substituted phenols, optionally substituted nitrogen heterocycles, optionally substituted aliphatic hydrocarbons, optionally substituted ketones, optionally substituted aliphatic ethers, optionally substituted cyclic ethers, optionally substituted oxygen heterocycles, optionally substituted esters, optionally substituted amides, and mixtures thereof.

[0028] Embodiment 12: The apparatus of any one of Embodiments 1-11, wherein the non-aqueous liquid solvent comprises a hydrophobic primary or secondary amine and a diluent comprising an optionally substituted aliphatic ether.

[0029] Embodiment 13: The apparatus of any one of Embodiments 1-12, wherein the non-aqueous liquid solvent comprises an ionic liquid.

[0030] Embodiment 14: The apparatus of any one of Embodiments 1-13, wherein the RPB is equipped with a cooling mechanism.

[0031] Embodiment 15: The apparatus of any one of Embodiments 1-14, further comprising a second RPB.

[0032] Embodiment 16: A system for removing one or more acid gas components from a gas stream, comprising the apparatus of any one of Embodiments 1-15.

[0033] Embodiment 17: The system of Embodiment 16, further comprising a regenerator in fluid communication with the liquid outlet.

[0034] Embodiment 18: The system of Embodiment 16 or 17, wherein the regenerator comprises a second RPB.

[0035] Embodiment 19: The system of any one of Embodiments 16-18, comprising one or more (eg, one, two, three, four, or more) additional RPBs.

[0036] Embodiment 20: A method for treating a gas stream to remove one or more acid gas components therefrom, comprising passing the gas stream into a gas inlet of the apparatus of any of Embodiments 1-15 or the system of any of Embodiments 16-19.

[0037] Embodiment 21: The method of Embodiment 20, wherein the gas stream is a flue gas stream.

[0038] Embodiment 22: The method of Embodiment 20 or 21, wherein the one or more acid gas components include CO2.

[0039] Embodiment 23: The method of any one of Embodiments 20-22, further comprising regenerating the non-aqueous liquid solvent to remove acid gas components therefrom.

[0040] Embodiment 24: A method of reducing capital and operating expenses associated with a system designed to capture acid gas components from a gas stream, comprising employing the apparatus of any one of Embodiments 1-15 in place of a conventional packed bed absorption apparatus within the system.

[0041] By reading the following detailed description and the accompanying drawings briefly described below, these and other features, aspects and advantages of the present disclosure will be apparent. The present invention includes any combination of two, three, four or more of the above-mentioned embodiments, and the combination of any two, three, four or more features or elements set forth in the present disclosure, and no matter whether such features or elements are clearly combined in the specific embodiment description of this paper. Unless context clearly stipulates otherwise, the present disclosure is intended to be read as a whole so that any separable features or elements of the disclosed invention should be considered as intended to be combinable in any one of its various aspects and embodiments. Other aspects of the present invention and advantages will become apparent from the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Having thus described the present disclosure in the foregoing general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0044] Figure 1 is a schematic diagram of a reboiler-based system for capturing acidic components from a mixed gas stream using a liquid solvent and regenerating the liquid solvent, according to certain embodiments of the present disclosure;

[0045] Figure 2is a schematic perspective view of a rotating packed bed (RPB) apparatus for gas-liquid contacting according to certain embodiments of the present disclosure;

[0046] Figure 3 is a graph of observed pseudo-first-order reaction rate constants for three different CO2 capture solvents that may be used in certain embodiments of the present disclosure;

[0047] Figure 4 is a graph of CO2 recovery for various solvents tested in an example of a rotating packed bed (RPB) apparatus according to one embodiment of the present disclosure; and

[0048] Figure 5 is a graph of the vapor-liquid equilibrium behavior of various solvents tested in an example of a rotating packed bed (RPB) apparatus according to one embodiment of the present disclosure.

[0049] Detailed description

[0050] The present disclosure will now be described more fully below with respect to exemplary embodiments thereof. These exemplary embodiments are described so that the present disclosure will be comprehensive and complete and will fully convey the scope of the present disclosure to those skilled in the art. Indeed, the present disclosure may 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 the present disclosure will satisfy applicable legal requirements. As used in the specification and the appended claims, the singular forms "a," "an," "the," etc. include plural referents unless the context clearly dictates otherwise.

[0051] As described below, the present disclosure relates to apparatus, systems, and methods for removing acid gases from various gas streams (typically, mixed gas streams). The terms "acid gas," "acid gas components," "acidic gas," and "acidic gas components" are intended to include gas components that can result in the formation of acids when mixed with water. Non-limiting examples of acid gases for which the disclosed apparatus, systems, and methods are applicable include carbon dioxide (CO2), carbonyl sulfide (COS), carbon disulfide (CS2), sulfur oxides (SO x , for example, SO2) or any combination thereof.

[0052] In particular, the present disclosure provides apparatus, systems, and methods for removing acid gases from gas streams using a rotating packed bed (RPB) through gas-liquid mass transfer with a non-aqueous liquid solvent. By employing a non-aqueous liquid solvent for gas-liquid contacting within an RPB-based system, improved gas-liquid absorption can be achieved for acid gas removal, resulting in significantly reduced operating costs, as outlined below, compared to systems based on aqueous solvent RPBs.

[0053] As provided herein, solvent-based systems and processes for removing acid gases generally include passing a gas stream to be treated through a liquid solvent; acid gas components (e.g., CO and the other acid gases mentioned above) interact with the liquid solvent, and the acid gas components are thereby separated from the remainder of the gas stream. This interaction between the liquid solvent and the acid gas components can be categorized as physical adsorption (using pressure to dissolve the acid components in the liquid solvent) and / or chemical absorption (forming a chemical bond between the acid components and the liquid solvent).

[0054] The liquid solvent becomes enriched with the acidic gas component, and the acidic gas component is typically removed to allow the liquid solvent to be recovered for further processing of the gas stream. For liquid solvents that remove the acidic component via physical absorption, removing the gaseous component from the rich liquid solvent typically involves reducing the pressure of the liquid solvent. For liquid solvents that remove the acidic component via chemical absorption, removing the gaseous component from the rich liquid solvent typically involves energy (e.g., heat) to reverse the reaction / break the chemical bonds formed between the liquid solvent and the acidic component.

[0055] exist Figure 1 The middle figure shows an exemplary gas processing system, where the system 10 includes an absorber 12 (configured to have a gas inlet for receiving a gas stream to be treated, a solvent inlet for receiving a lean solvent influent, and a gas outlet and a liquid outlet for removing treated gas and a rich solvent effluent, respectively, from the absorber) and an optional regenerator / desorber 14. The figure is intended to be exemplary in nature, and the systems provided herein may be arranged in alternative manners and may include any number of additional (not shown) components.

[0056] According to the present disclosure, the absorber 12 includes, for example, Figure 2 A rotating packed bed (RPB) is schematically illustrated in FIG. Compared to conventional packed column-based systems, RPBs allow for significant reductions in absorber size and cost. RPBs employ countercurrent gas-liquid scrubbing but use centrifugal force to increase the gas-liquid interfacial area.

[0057] Although system 10 is illustrated as including a single RPB (12), it should be noted that this description is not intended to be limiting. In some embodiments, two (or more) RPBs may be included in the system, e.g., in series. For example, in some embodiments, the solvent is advantageously cooled between absorption stages, and the gas and liquid are passed countercurrently through a series of two or more RPBs. In one exemplary embodiment, the gas passes through RPB 1, then through RPB 2, and so on; and the liquid travels in the other direction (e.g., from 2 to 1 in the example including two RPBs), exchanging heat between them. Such a system may include two (or more) completely separate RPBs, or may include RPBs connected on the same axis in separate stages.

[0058] RPBs and their characteristics are generally known, as described, for example, in U.S. Pat. No. 4,400,275 to Ramshaw et al.; U.S. Pat. No. 8,679,232 to Wolf et al.; and U.S. Pat. No. 9,987,589 to Kotagiri et al.; U.S. Patent Application Publication No. 2016 / 0243495 to Dutra et al. and U.S. Patent Application Publication No. 2020 / 0261846 to Mobley et al.; Wang et al., Ind. Eng. Chem. Res. 2008, 47, 8840-8846; Cortes Garcia et al., J. Chem. Tech. Biotech. 2017, 92(6), 1136-1156; Chamchan et al., J. Taiwan Inst. Chem. Eng. 2017, 73, 20-26; and Li et al., Chinese J. Chem. Eng. 2009, 17(3), which are incorporated herein by reference in their entirety. The exact type and configuration of the RPB employed in accordance with the present disclosure are not particularly limited. For example, the flow directions of the liquid and the gas to be treated relative to each other can vary. In some embodiments, the RPB can be a cross-flow RPB; in some embodiments, the RPB can be a counter-flow RPB. Other configurations such as a rotating zigzag bed (RZB) are also known and can be used as an RPB in the context of the present disclosure. The rotor design can vary widely, for example, including different numbers of moving disks and / or stationary disks. Non-limiting examples of specific RPB designs that have been previously reported include, for example, multi-stage spray rotating packed beds, RPBs with wave-form disk packing, spiral rotating absorbers, RPBs with split packing, baffled rotating beds (RZBs), two-stage countercurrent rotating packed beds, bladed rotating packed beds, countercurrent concentric ring rotating beds, and cross-flow concentric baffle rotating beds, as summarized in Cortes Garcia et al., J. Chem. Tech. Biotech 2017, 92(6), 1136-1156, which is incorporated herein by reference in its entirety. In some embodiments, the RPB can include one or more intercoolers (e.g., applied to the solvent between RPB stages) or one or more heating / cooling systems, which can be fixed and / or rotating and have different designs. In certain embodiments, an RPB having a heating / cooling system of the type described in U.S. Patent Application Publication No. 2020 / 0261846 to Mobley et al., which is incorporated herein by reference in its entirety, may be employed.

[0059] As described herein, the use of non-aqueous liquid solvents within the RPB results in particularly advantageous results not previously recognized. According to the present disclosure, an RPB is provided wherein the non-aqueous liquid solvent is introduced through the liquid inlet of the RPB (see Figure 2 ); a gas stream to be treated enters through the gas inlet of the RPB as shown, and acidic gas components within the gas stream to be treated can interact with the non-aqueous liquid solvent within the RPB. The non-aqueous liquid solvent reacts with the acidic gas components, capturing them from the remaining components of the gas stream. The capture can be based on chemical absorption and / or physical absorption. The non-aqueous liquid solvent advantageously provides unique benefits within RPB-based systems, for example, because the film thickness of the non-aqueous liquid solvent limits the mass transfer rate in the bulk solvent. In a preferred embodiment, the non-aqueous liquid solvent is regenerable, i.e., the captured acidic components can be released from the solvent, and the solvent can then be reused to separate additional acidic components from another gas stream.

[0060] The solvent employed within an RPB according to the present disclosure may vary, however for purposes of the present disclosure, the solvent comprises (or consists essentially of) a non-aqueous liquid solvent. A non-aqueous liquid solvent is understood to be a liquid other than water, and is typically an organic solvent system that is miscible with a small amount of water (0 to about 20 weight / weight percent, 0 to about 10 weight / weight percent, and preferably less than about 10 weight / weight percent water). Non-aqueous liquid solvents include both protic and aprotic solvents, and combinations thereof. During operation of a carbon capture unit and a non-aqueous liquid solvent system for removing CO2 from exhaust or other water-laden gas streams, it is generally desirable to accumulate a certain amount of water (e.g., about 2%-8% water) without any interference with the operation of the system and with little performance change in the energy and capture efficiency of the system.

[0061] In some embodiments, the solvent comprises about 18% or less water by weight, about 15% or less water by weight, about 12% or less water by weight, about 10% or less water by weight, or less than 10% water by weight (e.g., about 0% water to about 18% water, about 0% water to about 12% water, or about 0% water to about 8% water, about 0% water to about 9% water, about 0% water to about 10% water). Under practical conditions for gas treatment processes, the water content in the solvent cannot be zero because water enters the system in the inlet gas stream and, in the case of treated gas, the water cannot be completely removed until enough water accumulates in the solvent to balance the water entering and leaving the absorber. The treated gas will not be saturated with water, and the relative humidity of the treated gas varies with the concentration of water in the solvent. Therefore, when the temperature and relative humidity of the gas are in equilibrium with the water in the solvent, a minimum amount of water must be present in the solvent to leave a sufficiently high amount of water in the treated gas. Thus, the water in the solvent can operate in different ranges for different gas streams and process conditions (e.g., about 2% water to about 18% water, about 2% water to about 15% water, or about 2% water to about 12% water, about 2% water to about 10% water, about 2% water to about 9% water, or about 2% water to about 8% water).

[0062] Various types of suitable non-aqueous liquid solvents, such as non-aqueous liquid solvents for removing acid gases from gas streams, are described, for example, in International Patent Application Publication No. WO2012 / 031274 to Lail et al.; International Patent Application Publication No. WO2012 / 031281 to Lail et al.; International Patent Application Publication No. WO2013 / 130997 to Lail et al.; International Patent Application Publication No. WO2015 / 123490 to Coleman et al.; U.S. Patent Application Publication Nos. 2009 / 0136402 and 2009 / 0220397 to Heldebrant et al.; U.S. Patent Application Publication No. US2020 / 0398216 to Rayer Rabindran et al.; International PCT Patent Application No. PCT / US2020 / 063892 filed December 9, 2020; Lail et al., Energy Procedia 2014, 63, 580-594; Mobley et al., Ind. Eng. Chem. Res. 2017, 56(41), 11958-11966; Rayer et al., Chem. Eng. J. 2018, 348, 514-525; Zhou et al., RTI International and SINTEF: Trondheim, Norway, 2017 (available at https: / / www.sintef.no / globalassets / project / tccs-9 / presentasjoner / a3 / 11---tccs-9---2017-06-12-nas-presentation-zhou.pdf); and Heldebrant et al., Chem. Rev. 2017, 117(114), 9594-9624, all of which are incorporated herein by reference in their entirety.

[0063] In certain embodiments, the non-aqueous liquid solvent comprises a mixture of a chemical absorbent and a physical absorbent (e.g., a diluent), although not limited thereto (and thus, in some embodiments, may comprise only one or more physical absorbents or only one or more chemical absorbents). Thus, in some embodiments, the non-aqueous liquid solvent comprises from about 1% to 100% (pure) of a chemical absorbent component relative to the total weight of the non-aqueous liquid solvent. Where a mixture of a chemical absorbent component and a physical absorbent component is provided, in some embodiments, these components may be present in approximately equal proportions by weight.

[0064] In some embodiments, the non-aqueous liquid solvent comprises up to about 70%, about 75%, about 80%, or about 90% by weight relative to the total weight of the non-aqueous liquid solvent (e.g., about 5% to about 90%, about 5% to about 80%, about 5% to about 70%, about 5% to about 60%, about 5% to about 50%, about 5% to about 40%, about 5% to about 30%, about 5% to about 20%, about 5% to about 10%, about 10% to about 90%, about 10% to about 80%, about 10% to about 70%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 10% to about 30%, about 10% to about 20%). % to about 80 wt %, about 20 wt % to about 70 wt %, about 20 wt % to about 60 wt %, about 20 wt % to about 50 wt %, about 20 wt % to about 40 wt %, about 30 wt % to about 90 wt %, about 30 wt % to about 80 wt %, about 30 wt % to about 70 wt %, about 30 wt % to about 50 wt %, about 30 wt % to about 40 wt %, about 40 wt % to about 90 wt %, about 40 wt % to about 80 wt %, about 40 wt % to about 70 wt %, about 40 wt % to about 60 wt %, about 40 wt % to about 50 wt %, about 50 wt % to about 90 wt %, about 50 wt % to about 80 wt %, about 50 wt % to about 70 wt %, or about 50 wt % to about 60 wt % of the chemical absorption component. In certain embodiments, the non-aqueous liquid solvent comprises less than 70% by weight of a chemical absorption component. In some embodiments, the non-aqueous liquid solvent comprises from about 30% to about 70% of a chemical absorption component. In some such embodiments, the remainder of the non-aqueous liquid solvent may comprise, for example, a physical absorption component, and in some embodiments, the remainder of the non-aqueous liquid solvent may comprise a small amount of water (e.g., about 10% or less by weight, about 8% or less by weight, or about 6% or less by weight) relative to the total weight of the non-aqueous liquid solvent. Examples of the types of physical absorbents and chemical absorbents that can be used as components of the non-aqueous liquid solvent as provided herein are summarized below.

[0065] The non-aqueous liquid solvent may include a chemical absorbent comprising one or more nitrogenous bases. In some embodiments, the nitrogenous base may have a pKa of about 8 to about 15, about 8 to about 14, about 8 to about 13, about 8 to about 12, about 8 to about 11, or about 8 to about 10. In certain embodiments, the nitrogenous base component has a pKa of less than about 11.

[0066] In certain embodiments, the non-aqueous liquid solvent comprises a chemical absorbent comprising one or more amines, such as primary and / or secondary amines. Primary amines are understood to be compounds of the formula NH2R, wherein R can be a carbon-containing group, including but not limited to C1-C 20 Alkyl. Secondary amines are understood to be compounds of the formula NHR1R2, wherein R1 and R2 are independently carbon-containing groups, including but not limited to C1-C 20 Alkyl. One or more hydrogen atoms on R, R1 and R2 may be optionally substituted with one or more substituents. For example, one or more hydrogen atoms on R, R1 or R2 may be substituted with: optionally substituted C1-C6 alkyl; optionally substituted C1-C6 alkoxy; optionally substituted C2-C 10 Alkenyl; optionally substituted C2-C 10 alkynyl; optionally substituted alkylaryl; optionally substituted arylalkyl; optionally substituted aryloxy; optionally substituted heteroaryl; optionally substituted heterocycle; halogen (e.g., Cl, F, Br, and I); hydroxy; haloalkyl (e.g., CF3, 2-Br-ethyl, CH2F, CH2CF3, and CF2CF3); haloaryl; haloalkylaryl; halobenzyl; optionally substituted amino; optionally substituted alkylamino; optionally substituted The amines may be substituted arylamino, optionally substituted acyl, CN, NO2, N3, CH2OH, CONH2, C1-C3 alkylthio, sulfate, sulfonic acid, sulfonate (e.g., methylsulfonyl), phosphonic acid, phosphate, phosphonate, monophosphate, diphosphate, or triphosphate, trityl or monomethoxytrityl, CF3S, CF3SO2, or silyl (e.g., trimethylsilyl, dimethyl-tert-butylsilyl, and diphenylmethylsilyl). The amines may be nucleophilic or non-nucleophilic.

[0067] In certain embodiments, the primary or secondary amine can be selected from amines functionalized with fluorinated alkyl aromatic groups. In a specific embodiment, the amine can be selected from the group consisting of 2-fluorophenethylamine, 3-fluorophenethylamine, 4-fluorophenethylamine, 2-fluoro-N-methylbenzylamine, 3-fluoro-N-methylbenzylamine and 4-fluoro-N-methylbenzylamine, 2-fluorobenzylamine, 3-fluorobenzylamine, 4-fluorobenzylamine, 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoroundecylamine, 2,3-difluorobenzylamine, 2,4-difluorobenzylamine, 2,6-difluorobenzylamine, 3,4-difluorobenzylamine, 3,5-difluorobenzylamine, 2-trifluoromethylbenzylamine, 3-trifluoromethylbenzylamine, 4-trifluoromethylbenzylamine, D-4-fluoro-α-methylbenzylamine and L-4-fluoro-α-methylbenzylamine. In some embodiments, non-fluorinated primary or secondary amines are used as chemical absorbents, for example, including but not limited to N-methylbenzylamine (MBZA), N-methylnaphthylamine, N-methyl-1-naphthylmethylamine, 1-(1-naphthyl)ethylamine, and combinations thereof.

[0068] In some embodiments, primary amine or secondary amine can include cyclamine, diamine, primary alcoholamine and / or secondary alcoholamine.Cyclic amine is an amine in which the nitrogen atom forms a part of a ring structure, and can include but is not limited to aziridine, azetidine, pyrrolidine, piperidine, piperazine, pyridine and pyrimidine.Cyclic amine can include one or more rings, and can optionally be substituted by one or more substituents as listed above. In some embodiments, amine can be a diamine. In some embodiments, amine can be a primary alcoholamine or a secondary alcoholamine. Alcoholamine is also referred to as amino alcohol, and contains both an alcohol group and an amine group. The amine group of alcoholamine can be any type of amine as disclosed herein. In certain embodiments, some amines (such as cyclamine) are functionalized with fluorine-containing groups.

[0069] Certain amines include, but are not limited to, 1,4-diazabicyclo-undec-7-ene ("DBU"); 1,4-diazabicyclo-2,2,2-octane; piperazine ("PZ"); triethylamine ("TEA"); 1,1,3,3-tetramethylguanidine ("TMG"); 1,8-diazabicycloundec-7-ene; monoethanolamine ("MEA"); diethylamine ("DEA"); ethylenediamine ("EDA"); 1,3-diaminopropane; 1,4-diaminobutane; hexamethylenediamine ; 1,7-diaminoheptane; diethanolamine; diisopropylamine ("DIPA"); 4-aminopyridine; pentylamine; hexylamine; heptylamine; octylamine; nonylamine; decylamine; tert-octylamine; dioctylamine; dihexylamine; 2-ethyl-1-hexylamine; 2-fluorophenethylamine; 3-fluorophenethylamine; 3,5-difluorobenzylamine; 3-fluoro-N-methylbenzylamine; 4-fluoro-N-methylbenzylamine; imidazole; benzimidazole; N-methylimidazole; 1-trifluoroacetylimidazole; 1,2,3-triazole; 1,2,4-triazole; and mixtures thereof.

[0070] In certain embodiments, the non-aqueous liquid solvent includes a chemical absorbent comprising one or more amidines, guanidines, or tertiary amines, each of which may be optionally substituted (eg, fluorinated).

[0071] Guanidine is understood to be a compound having the structure RNC(NR1R2)2, wherein R, R1 and R2 are independently H or a carbon-containing group, including but not limited to C1-C 20 Alkyl. One or more hydrogen atoms on R, R1 and / or R2 may be optionally substituted with one or more substituents. For example, one or more hydrogen atoms on R, R1, R2 and R3 may be substituted with: optionally substituted C1-C6 alkyl; optionally substituted C1-C6 alkoxy; optionally substituted C2-C 10 Alkenyl; optionally substituted C2-C 10 alkynyl; optionally substituted alkylaryl; optionally substituted arylalkyl; optionally substituted aryloxy; optionally substituted heteroaryl; optionally substituted heterocycle; halogen (e.g., Cl, F, Br, and I); hydroxy; haloalkyl (e.g., CF3, 2-Br-ethyl, CH2F, CH2CF3, and CF2CF3); haloaryl; haloalkylaryl; halobenzyl; optionally substituted amino; optionally substituted alkylamino; optionally substituted substituted arylamino; optionally substituted acyl; CN; NO2; N3; CH2OH; CONH2; C1-C3 alkylthio; sulfate; sulfonic acid; sulfonate (e.g., methylsulfonyl); phosphonic acid; phosphate; phosphonate; monophosphate, diphosphate, or triphosphate; trityl or monomethoxytrityl; CF3S; CF3SO2; or silyl (e.g., trimethylsilyl, dimethyl-tert-butylsilyl, and diphenylmethylsilyl).

[0072] Amidines include, but are not limited to, carboxamidine / carboximidamide, which are understood to be compounds having the structure RC(=NH)NR1R2, wherein R, R1, and R2 are independently H or carbon-containing groups, including but not limited to C1-C 20 Alkyl. One or more hydrogen atoms on R, R1 and / or R2 may be optionally substituted with one or more substituents. For example, one or more hydrogen atoms on R, R1, R2 and R3 may be substituted with: optionally substituted C1-C6 alkyl; optionally substituted C1-C6 alkoxy; optionally substituted C2-C 10 Alkenyl; optionally substituted C2-C 10alkynyl; optionally substituted alkylaryl; optionally substituted arylalkyl; optionally substituted aryloxy; optionally substituted heteroaryl; optionally substituted heterocycle; halogen (e.g., Cl, F, Br, and I); hydroxy; haloalkyl (e.g., CF3, 2-Br-ethyl, CH2F, CH2CF3, and CF2CF3); haloaryl; haloalkylaryl; halobenzyl; optionally substituted amino; optionally substituted alkylamino; optionally substituted substituted arylamino; optionally substituted acyl; CN; NO2; N3; CH2OH; CONH2; C1-C3 alkylthio; sulfate; sulfonic acid; sulfonate (e.g., methylsulfonyl); phosphonic acid; phosphate; phosphonate; monophosphate, diphosphate, or triphosphate; trityl or monomethoxytrityl; CF3S; CF3SO2; or silyl (e.g., trimethylsilyl, dimethyl-tert-butylsilyl, and diphenylmethylsilyl).

[0073] Exemplary guanidines and amidines include, but are not limited to, 1,1,3,3-tetramethylguanidine ("TMG"); N-tert-butyl-1,1,3,3-tetramethylguanidine, diphenylguanidine, ditolylguanidine, 1,8-diazabicyclo(5.4.0)undec-7-ene, 1,1,3-trimethyl-3-(2,2,3,3-tetrafluoropropyl)guanidine; 1,1,3-trimethyl-3-(2,2,3,3,3-pentafluoropropyl)guanidine; 1,3-dimethyl-1,3-bis(2,2,2-trifluoroethyl)guanidine; Guanidine; 1,3-bis(2,2,3,3-tetrafluoropropyl)guanidine; 1,3-bis(4-fluorophenyl)guanidine; 1,3-bis(3-fluorophenyl)guanidine; 1,3-bis(2-fluorophenyl)guanidine; 2-(2,2,2-trifluoroethyl)-1,4,5,6,-tetrahydropyrimidine; 2-(2,2,3,3-tetrafluoropropyl)-1,4,5,6,-tetrahydropyrimidine; 3,3,4,4-tetrafluoro-N,N-dimethylbutanemidine; 3,3,3-trifluoro-N,N-dimethylpropanemidine; and mixtures thereof.

[0074] Tertiary amines are understood to be compounds having the formula NR1R2R3, wherein R1, R2 and R3 are independently carbon-containing groups, including but not limited to C1-C 20 Alkyl. One or more hydrogen atoms on R, R1, R2 and R3 may be optionally substituted with one or more substituents. For example, one or more hydrogen atoms on R, R1, R2 and R3 may be substituted with: optionally substituted C1-C6 alkyl; optionally substituted C1-C6 alkoxy; optionally substituted C2-C 10 Alkenyl; optionally substituted C2-C 10alkynyl; optionally substituted alkylaryl; optionally substituted arylalkyl; optionally substituted aryloxy; optionally substituted heteroaryl; optionally substituted heterocycle; halogen (e.g., Cl, F, Br, and I); hydroxy; haloalkyl (e.g., CF3, 2-Br-ethyl, CH2F, CH2CF3, and CF2CF3); haloaryl; haloalkylaryl; halobenzyl; optionally substituted amino; optionally substituted alkylamino; optionally substituted substituted arylamino; optionally substituted acyl; CN; NO2; N3; CH2OH; CONH2; C1-C3 alkylthio; sulfate; sulfonic acid; sulfonate (e.g., methylsulfonyl); phosphonic acid; phosphate; phosphonate; monophosphate, diphosphate, or triphosphate; trityl or monomethoxytrityl; CF3S; CF3SO2; or silyl (e.g., trimethylsilyl, dimethyl-tert-butylsilyl, and diphenylmethylsilyl).

[0075] In some embodiments, the non-aqueous liquid solvent comprises a physical absorbent, and this physical absorbent comprises a non-aqueous diluent.Diluent does not participate in the acidic gas (for example CO ) removed from gas stream usually.In certain embodiments, select diluent so that it and water have low miscibility.Some non-aqueous diluents can be relatively acidic (having the acidity greater than water, preferably substantially greater than water acidity, for example, having less than about 15, less than about 14, less than about 13, less than about 12, less than about 11 or less than about 10, such as approximately 6 to about 15, approximately 7 to about 15, approximately 8 to about 15, approximately 9 to about 15, approximately 6 to about 14, approximately 7 to about 14, approximately 8 to about 13, approximately 9 to about 13, approximately 6 to about 12, approximately 7 to about 12, approximately 8 to about 12, approximately 9 to about 12, approximately 6 to about 11, approximately 7 to about 11, approximately 8 to about 11, approximately 9 to about 11, approximately 6 to about 10, approximately 7 to about 10 or approximately 8 to about 10 pKa). Some non-aqueous diluents are not relatively acidic components and do not have a pKa that falls within the ranges mentioned above. For example, in certain embodiments, the non-aqueous diluent may have a pKa greater than about 15.

[0076] Exemplary classes of relatively acidic diluents that can be used in accordance with the present disclosure include, but are not limited to, the following: fluorinated alcohols; optionally substituted phenols; and nitrogen heterocycles. Useful fluorinated alcohols according to the present invention may include any compound having the formula R—OH, wherein R is an alkyl group (e.g., C1-C 10 Alkyl, C1-C8 alkyl, C1-C6 alkyl, C2-C 10 Alkyl, C2-C8 alkyl, C2-C6 alkyl, C3-C 10In some embodiments, the phenols of the present invention are substituted phenols of the present invention, wherein ... Non-limiting, exemplary substituents for one or more hydrogen atoms on the ring include C1-C6 alkyl, C1-C6 alkoxy, and halogen substituents.

[0077] In some specific embodiments, the diluent (e.g., a relatively acidic diluent) can be selected from the group consisting of: 2,2,3,3,4,4,5,5-octafluoropentanol ("OFP"); 2,2,3,3-tetrafluoropropanol ("TFP"); 2,2,3,3,3-pentafluoropropanol ("PFP"); 2,2,3,3,4,4-hexafluorobutanol ("HFB"); 2,2,2-trifluoroethanol ("TFE"); nonafluoro-1-hexanol; 4,4,5,5, 6,6,7,7,7-nonafluoroheptanol; 1,1,3,3-hexafluoro-2-phenyl-2-propanol, 4-methoxyphenol ("4-MeOPh"); 4-ethoxyphenol ("4-EtOPh"); 2-ethoxyphenol; 4-propoxyphenol; imidazole; benzimidazole; N-methylimidazole; 1-trifluoroacetylimidazole; 1,2,3-triazole; 1,2,4-triazole; 2-trifluoromethylpyrazole; 3,5-bis(trifluoromethylpyrazole); 3-trifluoromethylpyrazole; and mixtures thereof.

[0078] In certain embodiments, the diluent may generally be selected from the group consisting of alcohols, ketones, aliphatic hydrocarbons, aromatic hydrocarbons, nitrogen heterocycles, oxygen heterocycles, aliphatic ethers, cyclic ethers, esters and amides, and mixtures thereof (all of which may be optionally substituted). In some embodiments, the diluent may be selected from the group consisting of fluorinated alcohols, fluorinated ketones, fluorinated aliphatic hydrocarbons, fluorinated aromatic hydrocarbons, fluorinated nitrogen heterocycles, fluorinated oxygen heterocycles, fluorinated aliphatic ethers, fluorinated cyclic ethers, fluorinated esters and fluorinated amides, and mixtures thereof. In a specific embodiment, the diluent can be selected from the group consisting of toluene, p-xylene, 1-methylnaphthalene, 2,4,6-dimethylaminophenol, benzyl alcohol, 2,6-dimethylcyclohexanone, 3,5-dimethylarsine, cyclohexanone, aniline, pyridine, 2-fluoroacetylphenone, 1-fluorodecane, 2,4-difluorobenzophenone, 2-fluoro-3-trifluoromethylaniline, 2-fluoroaniline, 4-fluoroaniline, 3-trifluoromethylacetophenone, 2-trifluoromethylacetophenone, bis(2,2,2-trifluoroethyl)methylphosphonate, 4-fluoro-3-(trifluoromethyl)benzaldehyde, and mixtures thereof.

[0079] In some embodiments, the non-aqueous liquid solvent may be in the form of an ionic liquid that can physically adsorb or chemically absorb acidic gas components, such as carbon dioxide. In particular, in certain embodiments of the present disclosure, hydrophobic viscous ionic liquids that are too viscous for use in flowing conventional column packings may be used as the non-aqueous liquid solvent.

[0080] In a specific embodiment, the non-aqueous liquid solvent used in the disclosed equipment, system and method includes a mixture of amine (e.g., hydrophobic amine) and substituted or unsubstituted alkyl ether. For example, the non-aqueous liquid solvent can include a mixture of secondary amine (e.g., hydrophobic secondary amine) and substituted or unsubstituted alkyl ether, the substituted or unsubstituted alkyl ether being such as polyglycol dibutyl ether (e.g., diethylene glycol dibutyl ether, triethylene glycol dibutyl ether, tetraethylene glycol dibutyl ether or any combination thereof). In some embodiments, the non-aqueous liquid solvent can adopt a mixture of primary amine and / or secondary amine (e.g., hydrophobic primary amine and / or hydrophobic secondary amine) and fluorinated alcohol (e.g., OFP, TFP, PFP or HFB). In some embodiments, the non-aqueous liquid solvent can adopt a mixture of primary amine and / or secondary amine (e.g., hydrophobic primary amine and / or hydrophobic secondary amine) and aliphatic hydrocarbon. In some embodiments, the non-aqueous liquid solvent may employ a mixture of optionally substituted amidines or guanidines and substituted or unsubstituted alkyl ethers.In various embodiments, other combinations of the components outlined above not specifically mentioned in combination are also contemplated herein.

[0081] In some embodiments, the non-aqueous liquid solvents described herein are substantially immiscible with water and have a solubility at 25° C. of less than or equal to about 25 g solvent / 100 mL water, less than or equal to about 20 g solvent / 100 mL water, less than or equal to about 10 g solvent / 100 mL water, less than or equal to about 9 g solvent / 100 mL water, less than or equal to about 8 g solvent / 100 mL water, less than or equal to about 7 g solvent / 100 mL water, less than or equal to about 6 g solvent / 100 mL water, less than or equal to about 5 g solvent / 100 mL water, less than or equal to about 4 g solvent / 100 mL water, less than or equal to about 3 g solvent / 100 mL water, less than or equal to about 2 g solvent / 100 mL water, less than or equal to about 1 g solvent / 100 mL water, less than or equal to about 0.5 g solvent / 100 mL water, less than or equal to about 0.1 g solvent / 100 mL water, or less than or equal to about 0.01 g solvent / 100 mL water. In some embodiments, the solvent system is completely immiscible with water. In some embodiments, solvent systems with low water miscibility may exhibit one or more of the following properties: they may require less energy for regeneration; may have a high CO2 loading capacity; may be able to tolerate water in the gas stream; and / or may be able to separate from water without a large energy penalty. It should be noted that while solvent system components with low miscibility with water are preferred, the present disclosure also includes solvent systems in which one or more components of the solvent system are at least partially miscible with water.

[0082] In some embodiments, any of the non-aqueous liquid solvents described herein tolerates the presence of water. In certain embodiments, the solvent system tolerates up to or equal to about 30% water by volume. For example, in some embodiments, the solvent system tolerates up to or equal to about 25% water by volume, up to or equal to about 20% water by volume, up to or equal to about 15% water by volume, up to or equal to about 10% water by volume, up to or equal to about 5% water by volume, up to or equal to about 2% water by volume, or up to or equal to about 1% water by volume. In some embodiments, tolerating the presence of water means that there is little to no degradation of solvent performance up to the volume of the indicated water. In some embodiments, the non-aqueous liquid solvent maintains the initial capacity for CO2 loading or approaches the initial capacity for CO2 loading when up to the volume of the indicated water. In some embodiments, the non-aqueous liquid solvent has a specific heat capacity less than 3.5 joules / gram ° C.

[0083] In some embodiments, the non-aqueous liquid solvent may also include one or more additional components. Additional components may be added, for example, to increase the solubility of the captured CO2 product in the solvent system and thereby avoid the formation of precipitates. However, in other embodiments, solid formation may be desired, and such formation may be enhanced by varying the concentration of one or more solvent system components.

[0084] The gas stream treated in accordance with the disclosed apparatus, systems and methods can vary, but is typically a waste gas that is desired to be treated prior to further use and / or release to the atmosphere. The source of the gas stream treated by the disclosed apparatus, systems and / or methods is not particularly limited, and can generally be any gas stream from which it is desired to be treated to remove one or more components (e.g., treated with a solvent to "wash" the gas stream of one or more undesirable components). In one embodiment, the waste gas is a post-combustion gas stream (also referred to herein as a "flue gas" stream), such as a post-combustion gas stream derived from the combustion of fossil fuels such as coal, oil or natural gas. The flue gas source can be, for example, from a power generation unit or industrial site, including coal, natural gas, biogas and biomass combustion, cement, iron, steel and waste incineration power plant operations. It is generally known that such gas streams contain acidic gas components, such as carbon dioxide (CO2) and due to environmental impacts and increasing regulations on the emission of such acidic gases, such post-combustion gas streams are typically treated to reduce their acidic gas content. It should be understood that the apparatus, systems, and methods provided herein can be adapted accordingly to remove any one or more contaminants applicable to a particular source of a gas stream, so long as the general principles outlined herein are employed (e.g., contacting a gas stream with a non-aqueous liquid solvent within an RPB for removing one or more components therefrom).

[0085] The temperature and pressure within the RPB can also be controlled. The RPB can be operated within a range of temperatures and pressures suitable for the disclosed apparatus, systems, and methods. For example, in one embodiment, the temperature of the absorber can be maintained at about 20°C to about 70°C, such as about 30°C to about 60°C or about 40°C to about 50°C, and the RPB can be maintained at a single temperature during use or can vary. Therefore, in some embodiments, the RPB is equipped with a heating and / or cooling system, as mentioned above, so that the operating temperature can be adjusted as needed. The RPB is typically operated at atmospheric pressure, but in some embodiments, the RPB can be operated at a pressure greater than atmospheric pressure. In addition, the rotational speed at which the RPB is operated can be varied and can be modified to obtain suitable gas component removal from the gas stream. In some embodiments, the liquid flow rate and the gas flow rate can be varied. The mass ratio of liquid to gas can be about 0.5 kg / kg to about 10 kg / kg or about 0.5 kg / kg to about 8 kg / kg. Specific examples of mass ratios of liquid to gas include, but are not limited to, ratios of about 0.83, about 1.67, about 2.5, about 3.33, about 0.49, about 0.98, about 1.46, and about 1.95, and all ranges therebetween.

[0086] The non-aqueous liquid solvent can be regenerated at any stage in the CO2 capture process. As the volume of gas stream processed within the RPB increases, the composition of the solvent within the unit can change. In particular, when the non-aqueous liquid solvent reacts with acidic gas components in the gas stream, reaction products are formed. Furthermore, flue gas typically contains some water content; therefore, in some embodiments, water can accumulate within the RPB. Furthermore, in some embodiments, reactions between other components of the gas and the solvent system can result in the production of additional species.

[0087] The gas processing system includes an optional regeneration system 14 to release the captured CO2 via a separate CO2 gas stream and thereby regenerate the solvent system. The regeneration system is configured to receive a feed of "rich" solvent from the RPB and return the regenerated solvent to the RPB once the CO2 has been separated from the "rich" solvent. The regeneration system may simply comprise a chamber with a heating unit that heats the solvent system to a temperature sufficient to release the gas and a release valve that allows the CO2 to be removed from the regeneration system. In some embodiments, it may be a distillation column; in other embodiments, the regeneration system may include an additional RPB. In embodiments where the regeneration system includes an RPB, the system is typically equipped with a heater that is applied to the solvent before it is introduced into the regeneration RPB, or the system is provided with a reboiler configuration (e.g., where steam is generated in the reboiler and is the gas inlet to the regeneration RPB). As will be appreciated by those skilled in the art, the operating temperature of the RPB used for regeneration is typically significantly higher than the temperatures mentioned above for the absorber RPB.

[0088] The regenerator may optionally be connected to one or more components. For example, the regenerator is preferably configured with means for delivering solvent to a unit where water can be decanted, centrifuged or otherwise removed from the system. The released CO2 can be separated / removed from the system and exported for storage or other intended use. The regenerated solvent system is again ready to absorb CO2 from the gas stream and can be directed back to the RPB. It will be understood that any of the liquid streams and / or gas streams associated with the rotating packed bed apparatus or components of a plurality of such apparatuses can be heated or cooled in a heat exchanger with a heating fluid or cooling fluid from any suitable source.

[0089] In some embodiments, the performance of the solvent within the RPB can be determined by its overall volumetric gas phase mass transfer coefficient (K G a) to describe, K G a is a representative measure of solvent performance in RPB. G Further details of the experimental determination and calculation of a are provided in the Examples below. In some embodiments, the properties of the non-aqueous liquid solvent within the RPB as provided herein are based on the corresponding K G The a value is significantly greater than the performance of other solvents previously studied in RPB. For example, in some embodiments, the K Ga is about 4 or greater, about 4.2 or greater, about 4.25 or greater, about 4.3 or greater, about 4.4 or greater, about 4.5 or greater, or about 5 or greater (e.g., in the range of about 4 to about 7, about 4.2 to about 7, about 4.25 to about 7, about 4.5 to about 7, or about 5 to about 7), for example for an L / G ratio above 0.45 kg / kg, such as for an L / G ratio of 0.45 kg / kg to 10 kg / kg.

[0090] The present disclosure includes RPB devices (e.g., Figure 2 ), a gas processing system including such an RPB device (e.g., as schematically illustrated in Figure 1 Thus, the present disclosure includes a method of treating a gas stream to remove acid gas components therefrom, wherein various parameters and features of the method can be modified to be consistent with the system disclosure provided above.

[0091] The devices, methods and systems outlined herein provide various advantages over known devices, methods and systems. Compared to known aqueous solvents for acid gas removal (e.g., aqueous solutions of monoethanolamine (MEA) under comparable conditions), the use of non-aqueous liquid solvents described herein in RPBs uniquely and unexpectedly provides significantly improved removal of acid gas components. In particular, as demonstrated in the experimental section below, the absorption kinetics of the non-aqueous liquid solvents in the RPBs are higher than those of the comparable aqueous monoethanolamine (MEA) solutions. This finding is unexpected and suggests that non-aqueous liquid solvents are particularly suitable for use in RPBs. In Rayer et al., Chem. Eng. J. 2018, 348, 514-525 (which is incorporated herein by reference in its entirety), non-aqueous liquid solvents are shown to have kinetic rates that are approximately one order of magnitude lower than aqueous MEA (see Figure 11 of Rayer et al.).

[0092] This application Figure 3The pseudo-first-order reaction rate constants observed for aqueous MEA are shown compared to two solvents with MBZA as the amine component. One solvent is aqueous (MBZA / H2O) and the other is a non-aqueous liquid solvent in which the primary diluent is triethylene glycol dibutyl ether and a small amount of water (<10 wt%). It is shown that the non-aqueous liquid solvent has a pseudo-first-order reaction rate constant observed to be much lower than that of MEA, but the same amine has a reaction rate constant about three times faster in aqueous solvent than aqueous MEA. Because higher specific heat and higher water vapor pressure increase energy losses, water is required as a diluent to obtain fast kinetics, thereby reducing the benefit of the non-aqueous liquid solvent. It is believed that the low conductivity and membrane thickness of the non-aqueous liquid solvent limit the mass transfer rate in the bulk solvent. Like conventional packed absorbers, RPBs allow countercurrent gas-liquid scrubbing, but they use centrifugal force to significantly increase the gas-liquid interface area with the membrane and can convert the process from mass transfer limited to kinetic limited. The experimental section below demonstrates that non-aqueous liquid solvents can react in RPBs at much faster kinetic rates than aqueous MEA without the need for aqueous diluents, which is believed to be caused by the membranes in the RPBs. Certain embodiments of the present disclosure can perform high levels of CO2 removal similar to (or better than) aqueous MEA solutions and can also provide significant cost benefits, as described in further detail below.

[0093] For example, by employing a non-aqueous liquid solvent-based RPB as an absorber in a gas processing system, the size of the absorber can be reduced compared to the prior art (e.g., compared to a system including a conventional packed tower absorber). In some embodiments, a system based on an RPB absorber as provided herein can be used to obtain acid gas removal comparable to (or better than) a conventional packed tower absorber-based system, wherein the RPB is at least about 5 times smaller than a conventional packed tower, at least about 8 times smaller than a conventional packed tower, at least about 10 times smaller than a conventional packed tower, at least about 15 times smaller than a conventional packed tower, or at least about 20 times smaller than a conventional packed tower. By reducing the size of the absorber, a related reduction in the overall spatial footprint of the acid gas component capture system can be obtained. Such advantages are particularly advantageous for applications in locations with physical constraints of limited space.

[0094] By employing RPBs based on non-aqueous liquid solvents as absorbers in gas processing systems, various costs can also be reduced compared to the prior art. The smaller size of the RPBs compared to conventional packed tower-based absorbers can provide a reduction in capital / equipment costs (CAPEX) compared to conventional packed tower-based absorbers. For example, the use of RPBs based on non-aqueous liquid solvents as provided herein can provide a reduction of more than 90% in absorber CAPEX compared to conventional packed tower-based absorbers. RPBs based on non-aqueous liquid solvents can also provide reduced operating costs for acid gas removal. Based on a reduction of more than 90% in absorber CAPEX, the total cost of acid gas capture for the system can be reduced by approximately 25% when using non-aqueous liquid solvents at a scale of 275t-CO2 / day compared to conventional equipment. In addition, based on model estimates, the use of non-aqueous liquid solvents in systems containing RPBs can provide lower reboiler loads than those associated with MEA (for example, including but not limited to, in the case of treating cement flue gas).

[0095] In certain embodiments, the use of the types of apparatus, methods, and systems provided herein can provide downstream advantages. For example, the reduced costs associated with acid gas capture as provided herein can result in the captured acid gas being suitable for commercial applications. Thus, in some embodiments, the disclosed methods can also include separating the captured acidic components after processing as described herein for use, for example, in enhancing oil recovery, producing chemicals, and various other processes that utilize acidic components such as CO2.

[0096] Many modifications and other embodiments of the present invention will occur to those skilled in the art to which this invention pertains, having the benefit of the teachings given in the foregoing description. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0097] experiment

[0098] Aspects of the present disclosure are more fully illustrated by the following examples, which are set forth for the purpose of illustrating certain aspects of the invention and are not to be construed as limiting the invention.

[0099] A non-aqueous solution (referred to herein as "Solvent A") containing approximately 50%-55% amine (MBZA) was provided, with the remainder being a polyethylene glycol alkyl ether diluent and water. Solvent A contained less than 10% by weight water and did not include an activator. Solvent A was evaluated as a solvent within an RPB using a system comprising a rotating packed bed mounted on a vertical axis (the rotor was placed within a Perspex tube to allow visual observation). The rotor packing was driven by an electric motor, and a rotary dry mist eliminator was mounted on the same axis above the running rotor to prevent droplets from following the gas exhaust. Two CO2 analyzers were installed before and after the rotor packing to determine the CO2 recovery rate, and a Fourier transform infrared (FTIR) detector was installed at the outlet to enable analysis of emissions from the system to the atmosphere.

[0100] The solvent (Solvent A) is preheated to the desired temperature (e.g., 40°C) in a lean tank and then fed through the rotating shaft. As the gas to be treated moves axially upward, the solvent flows radially and is ultimately delivered to a receiving tank. Air is heated by an electric heater and supplied to the rotating packed bed by a fan; CO2 is introduced directly into the inlet and mixed with the air to produce "artificial flue gas" with a CO2 concentration of approximately 1 mol%.

[0101] Set the following parameters for the test:

[0102] -Liquid flow rate (L) = 5kg / min, 10kg / min, 15kg / min and 20kg / min

[0103] -Gas flow (G) = 6kg / min and 10kg / min

[0104] - Initial CO2 loading (α) = 0.115 mol-CO2 / mol-amine

[0105] - Speed ​​ω = 820 rpm;

[0106] -Gas temperature (T 气体 )=40℃

[0107] -Liquid temperature (T 液体 )=40℃

[0108] -CO2≈1mol% in inlet gas

[0109] Solvent A was tested in a RPB system to evaluate CO2 recovery based on previous CO2 capture tests with coal flue gas, where a typical lean loading of about 0.115 mol / mol was found (which can be compared to the typical lean loading of MEA aqueous solution (about 0.2 mol / mol)). Similar test conditions in another cross-flow RPB (1 mol% CO2 in the inlet gas and 900 rpm, using three different solvents) are reported in Lin and Chen, Chemical Engineering Research and Design 89 (2011) 1722-1729, which is incorporated herein by reference in its entirety. To compare the experimental performance of Solvent A with other solvents in the literature, the experimental total volumetric gas phase mass transfer coefficient (K G a) is a representative measure of solvent performance in RPB. K G a is defined in Lin and Chen as:

[0110]

[0111] where Q G is the volume flow rate of gas, Z B is the axial length of the cross-flow RPB, and R i and R o are the inner and outer radii of the cross-flow RPB, respectively. i and C o is the concentration of CO2 in the inlet and outlet gas streams. Figure 4 The K values ​​of these different solvents are shown in G Comparison of a as a function of liquid to gas flow ratio (open symbols are from Lin and Chen, solid symbols are solvent A tests, open circles are MEA, open diamonds are NaOH, and open squares are AMP). See also Lin and Chen, Chem. Eng. Res. Des., 89(9), September 2011, pp. 1722-1729, which is incorporated herein by reference in its entirety. Figure 4 It can be seen that the experimental K of solvent A (0.115 mol / mol) G a increases logarithmically with the increase of L / G, which is consistent with the trend of other solvents. K of solvent A G The trend line of a is 1.658ln(L / G)+5.905, where R 2 is 0.95.

[0112] Under similar operating conditions, it was found that the K GThis result is more significant when considering that these tests were performed at 1 vol% CO2, which approximates the equilibrium rich loading of solvent A at a partial pressure of 1 kPa ( Figure 5 ), whereas the equilibrium rich loading of MEA is ~0.45 mol / mol. However, in this case, the use of solvent A only requires a shift in the CO2 loading range. A rich loading of approximately 0.12 mol CO2 / mol amine at 1 vol% requires a lean loading close to 0 mol CO2 / mol amine, which is possible with regeneration at 120°C. In contrast, the high absorption rate shown for a starting CO2 loading of 0.115 mol CO2 / mol amine indicates that solvent A maintains very fast kinetics near vapor-liquid equilibrium, as shown in Figure 2. Figure 5 Lin and Chen did not include the CO2 loading of the solvents tested, but it is possible that they were fresh solvents containing 0 mol / mol CO2 loading. For example, at an L / G ratio of ~2.5 kg / kg, the K of solvent A was G The average increase in a was about 500% higher than that of the 1 mol / L MEA aqueous solution (6.98 compared to 1.16 1 / s - representing a very significant increase), as shown in Table 1 below. Very high K G a shows that non-aqueous liquid solvents in RPBs have very fast kinetics and can effectively remove acid gas components from gas streams in much smaller RPBs than aqueous MEA, thereby significantly reducing the capital cost of the equipment.

[0113] Table 1 : Experimental total volumetric gas phase mass transfer coefficient of solvent A at different liquid and gas flow rates.

[0114]

Claims

1. An apparatus for removing one or more acid gas components from a gas stream, comprising a rotating packed bed (RPB) arranged on a rotatable shaft, the RPB comprising: a gas inlet through which an influent gas can enter for gas-liquid contacting; a gas outlet through which effluent gas can exit after said gas-liquid contacting; a liquid inlet through which liquid can enter for the gas-liquid contact; a liquid outlet through which the liquid can exit after the gas-liquid contacting; as well as a conduit between the liquid inlet and the liquid outlet, the conduit comprising a non-aqueous liquid solvent contained therein for the gas-liquid contacting, wherein the non-aqueous liquid solvent comprises 18% or less by weight of water, and wherein the non-aqueous liquid solvent has a solubility in water of less than 25 g water / 100 g of the non-aqueous liquid solvent, wherein the non-aqueous liquid solvent removes the one or more acid gas components via chemical absorption, and The non-aqueous liquid solvent comprises a hydrophobic primary amine and / or a hydrophobic secondary amine and a diluent, and the diluent comprises an aliphatic ether.

2. The apparatus of claim 1, wherein the non-aqueous liquid solvent is a solvent for removing acid gases from a flue gas stream.

3. The apparatus of claim 1 , wherein the non-aqueous liquid solvent comprises 10% by weight or less of water.

4. The apparatus of claim 1 , wherein the non-aqueous liquid solvent comprises 2% to 10% by weight water.

5. The apparatus of claim 1, wherein the non-aqueous liquid solvent has a kGa value of 4 or greater for an L / G ratio greater than 0.45 kg / kg.

6. The apparatus of claim 1, wherein the non-aqueous liquid solvent has a kGa value of 4 to 8 for an L / G ratio of 0.45 kg / kg to 8 kg / kg.

7. The apparatus of claim 1, wherein the non-aqueous liquid solvent comprises a physical absorbent and a chemical absorbent.

8. The apparatus of claim 1, wherein the non-aqueous liquid solvent comprises one or more hydrophobic primary amines and / or one or more hydrophobic secondary amines.

9. The apparatus according to claim 8, wherein the non-aqueous liquid solvent comprises 40% to 80% of the one or more hydrophobic primary amines and / or the one or more hydrophobic secondary amines.

10. The apparatus of claim 1 , wherein the non-aqueous liquid solvent comprises one or more diluents selected from the group consisting of optionally substituted alcohols, optionally substituted phenols, optionally substituted nitrogen heterocycles, optionally substituted aliphatic hydrocarbons, optionally substituted ketones, optionally substituted aliphatic ethers, optionally substituted cyclic ethers, optionally substituted oxygen heterocycles, optionally substituted esters, optionally substituted amides, and mixtures thereof.

11. The apparatus of claim 1 , wherein the non-aqueous liquid solvent comprises an ionic liquid.

12. The apparatus of claim 1, wherein the RPB is equipped with a cooling mechanism.

13. The apparatus of claim 1, further comprising a second RPB.

14. A system for removing one or more acid gas components from a gas stream, comprising the apparatus according to any one of claims 1 to 13.

15. The system of claim 14, further comprising a regenerator in fluid communication with the liquid outlet.

16. The system of claim 15, wherein the regenerator comprises a second RPB.

17. A method for treating a gas stream to remove one or more acid gas components therefrom, comprising passing the gas stream into the gas inlet of the apparatus according to any one of claims 1 to 13.

18. The method of claim 17, wherein the gas stream is a flue gas stream.

19. The method of claim 17 or 18, wherein the one or more acid gas components comprises CO2.

20. The method of claim 17 or 18, further comprising regenerating the non-aqueous liquid solvent to remove the acid gas component therefrom.

21. A method of reducing capital and operating expenses associated with a system designed for capturing acid gas components from a gas stream, comprising employing the apparatus of any one of claims 1 to 13 in place of a conventional packed bed absorption apparatus within the system.

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