Regeneration device, gas treatment device, regeneration method, and gas treatment method

Abstract

A regeneration device is a device that regenerates a treatment liquid in a phase separation state by absorbing an acidic compound by heating the treatment liquid to release the acidic compound. The regeneration device includes a container that houses the treatment liquid, and a first wall portion that divides a space in the container into a first space and a second space. The first space includes a heating region that receives the treatment liquid supplied from outside the container and is provided with a heating portion that heats the treatment liquid, and a standing region that receives the treatment liquid from which the acidic compound is released by heating of the heating portion from the heating region. The second space is a space that can discharge the treatment liquid from which the acidic compound is released. An opening is formed in the first wall portion to allow the treatment liquid in the standing region to flow into the second space.

Description

Technical Field

[0001] This invention relates to a regeneration device, a gas treatment device, a regeneration method, and a gas treatment method. Background Technology

[0002] Conventionally, a technique is known to separate acidic compounds by contacting a gas to be treated containing an acidic compound with a treatment liquid. As such a technique, for example, as described in Non-Patent Document 1 below, is known to use a treatment liquid that is liquid-phase separated into a first phase fraction (e.g., an amine phase) containing a high concentration of acidic compounds and a second phase fraction (e.g., an ether phase) containing a low concentration of acidic compounds.

[0003] The gas treatment apparatus described in Non-Patent Document 2 below includes: an absorber for absorbing acidic compounds in the gas to be treated with a treatment liquid; a regenerator for removing the acidic compounds from the treatment liquid by heating; and a circulation path for introducing the treatment liquid from the absorber to the regenerator and for returning the treatment liquid from the regenerator to the absorber. In this apparatus, the treatment liquid that has undergone phase separation in the absorber is supplied to the regenerator without being separated into two liquids: a first phase and a second phase. Thus, by supplying the phase-separated liquid to the regenerator without separating it into two liquids, the contact area between the first and second phases is increased, thereby promoting the regeneration of the treatment liquid (release of acidic compounds).

[0004] Regarding the regeneration promotion of the treatment liquid based on the increased contact area between the first phase (e.g., the amine phase) and the second phase (e.g., the ether phase), the extraction of regenerated amines through the second phase is explained as follows. In the phase-separated liquid, acidic compounds are mostly present in the first phase. Specifically, when the acidic compound is CO2 and the treatment liquid is a primary amine, the acidic compound is primarily RNH3. + +RNHCOO - These forms exist within the first phase.

[0005] If these are heated, through RNH3 + +RNHCOO - → The reaction 2RNH2 + CO2 separates the treated liquid into regenerated amine (RNH2) and CO2, thus regenerating the treated liquid. At this point, the regenerated amine is extracted into the second phase. Therefore, the separation reaction within the first phase readily proceeds to the right in the above reaction equation, and CO2 is easily released. This extraction of regenerated amine using the second phase occurs at the liquid-liquid interface between the first and second phases; therefore, increasing their contact area promotes CO2 release.

[0006] In Non-Patent Document 2, by supplying the phase-separated treatment liquid to the regenerator without separating it into two liquids, the contact interface between the first and second phase portions is increased, which promotes the release of acidic compounds. However, in Non-Patent Document 2, when the regenerated treatment liquid is returned from the regenerator to the absorber, there is a possibility that the treatment liquid in its phase-separated state before regeneration may be mixed in, and there is room for improvement in this regard.

[0007] Non-patent literature 1: Hiroshi Machida et al., “Development of phase separation solution for CO2 capture by aqueous (amine+ether) solution”, Journal of Chemical Thermodynamics, Elsevier Ltd., 2017, Vol. 113, pp. 64-70

[0008] Non-patent document 2: Hiroshi Machida et al., "Low temperature swing process for CO2 absorption-desorption using phase separation CO2 capture solvent", International Journal of Greenhouse Gas Control, (USA), Elsevier Ltd., 2018, Vol.75, p.1-7 Summary of the Invention

[0009] The purpose of this invention is to provide a regeneration apparatus and method that can promote the release of acidic compounds and selectively extract the regenerated treatment liquid, a gas treatment apparatus equipped with the regeneration apparatus, and a gas treatment method for performing the regeneration method.

[0010] One aspect of the present invention relates to a regeneration apparatus for regenerating a treatment liquid that is in a phase-separated state by absorbing an acidic compound, thereby releasing the acidic compound. The regeneration apparatus includes: a container for containing the treatment liquid; and a first wall dividing the space within the container into a first space and a second space. The first space includes: a heating zone receiving the treatment liquid supplied from outside the container and equipped with a heating element for heating the treatment liquid; and a settling zone receiving the treatment liquid from the heating zone after the acidic compound has been released by heating with the heating element. The second space is a space capable of discharging the treatment liquid after the release of the acidic compound to the outside of the container. An opening is formed in the first wall to allow the treatment liquid in the settling zone to flow into the second space.

[0011] Another aspect of the present invention relates to a gas treatment apparatus comprising: an absorption device that causes the treatment liquid to absorb acidic compounds contained in the gas being treated by contacting the gas being treated with the treatment liquid; and the above-described regeneration device.

[0012] Another aspect of the present invention relates to a regeneration method comprising the following steps: supplying a treatment liquid that has been phase-separated by absorbing an acidic compound to a first space within a container; releasing the acidic compound from the treatment liquid by heating the treatment liquid supplied to the first space; and allowing the treatment liquid after the release of the acidic compound to stand in the first space, and then allowing the treatment liquid to flow from the first space into the second space through an opening formed in the wall separating the first space and the second space.

[0013] Another aspect of the present invention relates to a gas treatment method comprising the following steps: contacting a gas to be treated containing an acidic compound with a treatment liquid in an absorption device, thereby causing the treatment liquid to absorb the acidic compound and thus separating the phases of the treatment liquid; conveying the phase-separated treatment liquid from the absorption device to a regeneration device; and performing the above-described regeneration method in the regeneration device to extract the treatment liquid after the release of the acidic compound from the regeneration device and return it to the absorption device. Attached Figure Description

[0014] Figure 1 This is a diagram schematically illustrating the structure of the gas processing apparatus according to the first embodiment.

[0015] Figure 2 This is a diagram schematically illustrating the structure of the absorption device in the first embodiment.

[0016] Figure 3 This is a diagram schematically illustrating the structure of the regeneration device according to the first embodiment.

[0017] Figure 4 This is a diagram schematically illustrating the structure of the regeneration device according to the second embodiment.

[0018] Figure 5 This is a diagram schematically illustrating the structure of the regeneration device according to the third embodiment.

[0019] Figure 6 This is a diagram schematically illustrating the structure of the regeneration device according to the fourth embodiment.

[0020] Figure 7 This is a diagram schematically illustrating the structure of the absorption device in other embodiments.

[0021] Figure 8 This is a diagram schematically illustrating the structure of the absorption device in other embodiments.

[0022] Figure 9 This is a schematic diagram illustrating the structure of the regeneration device involved in other embodiments.

[0023] Figure 10 This is a schematic diagram illustrating the structure of the regeneration device involved in other embodiments.

[0024] Figure 11 This is a schematic diagram illustrating the structure of the regeneration device involved in other embodiments.

[0025] Figure 12 This is a schematic diagram illustrating the structure of the regeneration device involved in other embodiments.

[0026] Figure 13 This is a schematic diagram illustrating the structure of the regeneration device involved in other embodiments. Detailed Implementation

[0027] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, these embodiments are merely examples embodying the present invention and are not intended to limit the scope of the invention.

[0028] (First Implementation)

[0029] <Gas Processing Unit>

[0030] First, based on Figure 1 The gas processing apparatus 1 according to the first embodiment will be described. The gas processing apparatus 1 is an apparatus that separates acidic compounds contained in a gas to be processed, such as CO2 gas, by contacting it with a processing liquid L1. First, the processing liquid L1 used in the gas processing apparatus 1 will be described in detail.

[0031] The treatment solution L1 is a liquid capable of reversibly absorbing and releasing acidic compounds such as CO2. It changes from a single-phase state to a two-phase separated state by absorbing the acidic compounds, and then returns to a single-phase state by releasing the acidic compounds. The treatment solution L1 is, for example, an alkaline absorbent containing water, an amine compound, and an organic solvent. As an example, it is preferable that the amine compound is 30 wt%, the organic solvent is 60 wt%, and the water is 10 wt%.

[0032] Examples of amine compounds include: primary amines such as 2-aminoethanol (MEA) and 2-(2-aminoethoxy)ethanol (AEE); secondary amines such as 2-(methylamino)ethanol (MAE), 2-(ethylamino)ethanol (EAE), and 2-(butylamino)ethanol (BAE); or tertiary amines such as triethanolamine (TEA), N-methyldiethanolamine (MDEA), tetramethylethylenediamine (TEMED), pentamethyldiethylenetriamine (PMDETA), hexamethyltriethylenetetramine, and bis(2-dimethylaminoethyl) ether.

[0033] As organic solvents, examples include 1-butanol, 1-pentanol, octanol, diethylene glycol diethyl ether (DEGDEE), or diethylene glycol dimethyl ether (DEGDME), and a mixture of these may also be used.

[0034] According to non-patent literature 1, if the combination of amine compounds and organic compounds is appropriately selected, it becomes an absorbent liquid that separates two phases by absorbing acidic compounds into a phase with a high content of acidic compounds and a phase with a low content of acidic compounds.

[0035] Next, the structure of gas processing device 1 will be described. For example... Figure 1 As shown, the gas processing device 1 mainly includes an absorption device 10, a regeneration device 20, a circulation path 30, a heat exchanger 40, and a heat pump 60.

[0036] In the absorption device 10, the gas to be treated comes into contact with the treatment liquid L1, thereby absorbing acidic compounds (e.g., CO2) contained in the gas to be treated. The absorption of acidic compounds in the absorption device 10 is an exothermic reaction.

[0037] like Figure 1 As shown, the absorption device 10 is connected to a gas supply path 11 for supplying the gas to be treated, a gas discharge path 12 for discharging the treated gas, a first flow path 31 for conveying the treated liquid L1 after absorbing CO2 to the regeneration device 20, and a second flow path 32 for returning the regenerated treated liquid L1 after releasing CO2 from the regeneration device 20 to the absorption device 10. The first flow path 31 and the second flow path 32 form a circulation path 30.

[0038] Gas supply path 11 is connected to the bottom of absorption device 10, and gas discharge path 12 is connected to the top of absorption device 10. The upstream end of the first flow path 31 branches into two flow paths (first branch 31A and second branch 31B), each branch 31A and 31B connected to the bottom of absorption device 10. Furthermore, infusion pumps 53 are installed in each branch 31A and 31B. The downstream end of the second flow path 32 is connected to the top of absorption device 10. An infusion pump 51 is also installed in the second flow path 32. The internal structure of absorption device 10 will be described in detail below.

[0039] The regeneration device 20 is an apparatus for regenerating the treatment liquid L1 by heating it, which is in a phase-separated state due to the absorption of acidic compounds, thereby releasing the acidic compounds from the treatment liquid L1. The release of the acidic compounds from the treatment liquid L1 is an endothermic reaction. In the regeneration device 20, if the treatment liquid L1 is heated, not only are the acidic compounds released, but a portion of the water contained in the treatment liquid L1 also evaporates.

[0040] like Figure 1 As shown, the regeneration device 20 is connected to the downstream end of the first flow path 31 and the upstream end of the second flow path 32. The first flow path 31 is connected to the bottom of the regeneration device 20, allowing the treatment liquid L1 discharged from the absorption device 10 to be introduced into the regeneration device 20. The second flow path 32 is also connected to the bottom of the regeneration device 20, allowing the treatment liquid L1 to be discharged from the regeneration device 20.

[0041] A supply path 21 is connected to the regeneration unit 20. Supply path 21 transports the acidic compound (e.g., CO2) obtained within the regeneration unit 20 to a supply destination. A condenser 22 is provided in supply path 21 to cool a mixture of the acidic compound gas and water vapor. If the mixture is cooled, the water vapor condenses, thus separating the water vapor from the acidic compound gas. The separated water vapor is returned to the regeneration unit 20 via a return path 24. The condenser 22 can be a heat exchanger using inexpensive cooling water such as river water. The internal structure of the regeneration unit 20 will be described in detail below.

[0042] Heat exchanger 40 is connected to the first flow path 31 and the second flow path 32, enabling heat exchange between the processed liquid L1 flowing through the first flow path 31 and the processed liquid L1 flowing through the second flow path 32. Heat exchanger 40 can be configured as, for example, a plate heat exchanger, or as a microchannel heat exchanger capable of heat exchange between fluids with relatively small temperature differences. This improves energy efficiency.

[0043] Heat pump 60 is a heat transfer unit that transfers the reaction heat generated in absorption device 10 to regeneration device 20. For example... Figure 1As shown, the heat pump 60 includes a closed-loop circulation path 65 containing refrigerant, and a compressor 62, an evaporator 61, an expansion mechanism 64, and a condenser 63 respectively disposed in the circulation path 65.

[0044] Evaporator 61, including heat transfer tubes, is disposed within absorption unit 10. Within absorption unit 10, an exothermic reaction occurs where the processed liquid L1 absorbs CO2. This heat of reaction is transferred to the liquid refrigerant flowing through evaporator 61. The liquid refrigerant flowing through evaporator 61 is heated and evaporated by this heat.

[0045] The gaseous refrigerant, compressed by compressor 62, flows into condenser 63. Condenser 63, including heat transfer tubes, is disposed within regeneration unit 20. Within regeneration unit 20, an endothermic reaction occurs, releasing CO2 from the processed liquid L1. The gaseous refrigerant flowing through condenser 63 condenses due to the heat generated by this endothermic reaction. At this time, processed liquid L1 is heated using condenser 63. That is, condenser 63 functions as a heating element for heating processed liquid L1. The condensed liquid refrigerant expands and depressurizes through expansion mechanism 64, then flows into evaporator 61. Thus, through refrigerant circulation, the reaction heat from absorption unit 10 is transferred to regeneration unit 20.

[0046] <Absorption device>

[0047] Next, based on Figure 2 The structure of the absorption device 10 will be described in more detail below. For ease of explanation, "up" and "down" represent the vertical direction, and "horizontal" represents the horizontal direction. For example... Figure 2 As shown, the absorption device 10 includes a container 13 as a tank in width, a first wall portion 18, a second wall portion 19, a gas supply portion 17, and a treatment liquid supply portion 14.

[0048] A tube sheet 15 is provided inside the container 13 to fix the heat transfer tubes of the evaporator 61. The heat transfer tubes are U-shaped with a wide cross section, and both ends are fixed to the tube sheet 15. Through the tube sheet 15, the space inside the container 13 is divided into an inlet space S8 for the refrigerant to enter and exit the heat pump 60, and a storage space S9 for storing the processing liquid L1. The heat transfer tubes of the evaporator 61 are arranged in the storage space S9.

[0049] Furthermore, as described above, by using a horizontally oriented tank (e.g., a pitcher-shaped container) as the container 13, even when attempting to further extend the heat transfer tubes of the evaporator 61 to expand the heat transfer area, this can be addressed by increasing the lateral dimension of the container 13. When the container 13 is longitudinally elongated, it is sometimes difficult to expand the heat transfer area beyond a certain extent due to height limitations, but this limitation does not exist when using a horizontally oriented tank. Therefore, the heat transfer area can be freely set to ensure the required heat transfer area.

[0050] The inlet / outlet space S8 is divided into an inlet space S1 and an outlet space S2 by a partition plate 16. Liquid refrigerant flowing from the circulation path 65 into the inlet space S1 enters the heat transfer tubes of the evaporator 61 through an opening at one end, flowing from that end to the other. During this process, the liquid refrigerant absorbs heat from the absorption reaction of the acidic compound and evaporates. Subsequently, the gaseous refrigerant flows out through the outlet space S2 back into the circulation path 65.

[0051] The first wall portion 18 is vertically disposed at the bottom of the container 13, separating the first space S3 and the second space S4 in the storage space S9. For example... Figure 2 As shown, the evaporator 61, the gas supply unit 17, and the processing liquid supply unit 14 are respectively disposed in the first space S3. In this embodiment, a liquid-permeable opening G1 is formed in the central part or below it in the height direction of the first wall part 18, specifically in the lowest part.

[0052] The second wall portion 19 is vertically disposed on the bottom of the container 13 on the opposite side of the evaporator 61 relative to the first wall portion 18, separating the second space S4 and the third space S5 in the storage space S9. Viewed from the first wall portion 18, the second wall portion 19 is located on the opposite side of the tube plate 15, and is disposed with a gap (second space S4) between it and the first wall portion 18. The second wall portion 19 is substantially parallel to the first wall portion 18, and its upper end is located below the upper end of the first wall portion 18 (bottom side of the container 13).

[0053] A first outlet 25 is provided at the bottom of container 13 facing the second space S4, and a second outlet 26 is provided at the bottom of container 13 facing the third space S5. One end of the first branch 31A is connected to the first outlet 25, and one end of the second branch 31B is connected to the second outlet 26.

[0054] The gas supply unit 17 is a nozzle for supplying the treated gas containing acidic compounds into the container 13 (first space S3), and is disposed at the bottom of the container 13. More specifically, the gas supply unit 17 is located below the heat transfer tube of the evaporator 61 and is configured with the gas outlet facing upward. In this embodiment, a plurality of gas supply units 17 are arranged at intervals along the bottom of the container 13, and the downstream end of the gas supply path 11 branches and connects to each gas supply unit 17.

[0055] The gas outlet of the gas supply unit 17 is located below the surface of the processing liquid L1. Accordingly, the ejected gas becomes bubbles and floats within the processing liquid L1, thus agitating the processing liquid L1. As a result, heat transfer from the processing liquid L1 to the refrigerant (flowing through the heat transfer tubes of the evaporator 61) in the heat pump 60 is promoted, and the gas-liquid contact between the gas being processed and the processing liquid L1 is improved to promote the absorption of acidic compounds. Alternatively, the gas outlet can be directed towards the heat transfer tubes of the evaporator 61, in which case heat transfer from the processing liquid L1 to the refrigerant is further promoted.

[0056] The processing fluid supply unit 14 is used to supply fluid from the regeneration unit 20 ( Figure 1 The returned treatment fluid L1 is supplied to container 13 (first space S3). The downstream end of the second flow path 32 is connected to the treatment fluid supply section 14. Figure 2 As shown, the processing liquid supply section 14 extends laterally, and a plurality of liquid supply ports are provided spaced apart laterally. The processing liquid supply section 14 is positioned above the heat transfer tubes of the evaporator 61 (above the liquid surface of the processing liquid L1) with the liquid supply ports facing downwards. The liquid supply ports of the processing liquid supply section 14 open directly above the first space S3, but may also open within the first space S3.

[0057] <Regeneration Device>

[0058] Next, based on Figure 3 The structure of the regeneration device 20 will be described in detail. For example... Figure 3 As shown, the regeneration device 20 includes a container 35 that is a tank in width, a first wall portion 39, and a processing liquid supply portion 38.

[0059] Container 35 is used to contain the absorber 10 ( Figure 2 The treatment liquid L1 is delivered. In addition, in this embodiment, the reason why the container 35 is a horizontally placed tank (e.g., a jug-shaped container) is the same as that for the absorption device 10, because the degree of freedom in setting the heat transfer area that facilitates heat exchange between the treatment liquid L1 and the refrigerant of the heat pump 60 is taken into consideration.

[0060] A first wall portion 39 is erected vertically at the bottom of container 35, dividing the space within container 35 into a first space S12 and a second space S13. The first space S12 includes: a heating region R1 where a processing liquid L1 is supplied and a heating unit (condenser 63) is provided to heat the processing liquid L1; and a settling region R2 where the processing liquid L1, after releasing acidic compounds through heating, is temporarily retained. The heating region R1 is a first receiving area for the processing liquid L1 supplied from outside container 35 to the first space S12. The settling region R2 is a second receiving area for the processing liquid L1 within the heating region R1, after at least the release of acidic compounds. The second space S13 is a space for discharging the processing liquid L1 after the release of acidic compounds, and is provided with an outlet 42 for the processing liquid L1.

[0061] A tube sheet 36 is provided inside the container 35 for fixing the heat transfer tubes of the condenser 63. The heat transfer tubes, which supply the refrigerant (heating medium) for heat exchange with the processing liquid L1, are in a wide U-shape and are fixed at both ends to the tube sheet 36. The tube sheet 36 separates the inlet / outlet space S10, which supplies the refrigerant to the heat pump 60, from the first space S12. The heating region R1 is the area in the first space S12 where the heat transfer tubes of the condenser 63 are located, and the stationary region R2 is the area adjacent to the heating region R1 and is the area in the first space S12 where the heat transfer tubes are not located (the area between the bottom of the U-shape of the heat transfer tube and the first wall 39).

[0062] The inlet / outlet space S10 is divided into an inlet space S6 and an outlet space S7 by a partition plate 37. Gaseous refrigerant flowing from the circulation path 65 into the inlet space S6 flows into the heat transfer tubes of the condenser 63 through an opening at one end, and then flows from that end to the other. At this time, the refrigerant is heated by the processing liquid L1, thereby releasing acidic compounds from the processing liquid L1 and causing the refrigerant to condense. Subsequently, the liquid refrigerant flows out through the outlet space S7 back to the circulation path 65.

[0063] The processing liquid supply unit 38 is a nozzle that supplies the pre-regeneration processing liquid L1 from the absorption device 10 to the heating zone R1, and is connected to the downstream end of the first flow path 31. In this embodiment, the processing liquid supply unit 38 is disposed on the bottom side of the container 35. More specifically, the processing liquid supply unit 38 extends along the bottom surface of the container 35 on the lower side of the condenser 63, and a plurality of supply ports (nozzle outlets) are provided spaced apart from each other. Each supply port faces upward (condenser 63 side), and the processing liquid L1 is supplied from the supply port toward the heat transfer tube of the condenser 63.

[0064] An opening 39A is formed in the first wall portion 39 to allow the treatment liquid L1 in the static area R2 to flow into the second space S13. For example... Figure 3As shown, the opening 39A is formed in the central portion of the first wall portion 39 in the height direction or in a portion located on the bottom side of the container 35 relative to the central portion, such that at least a portion overlaps with the heat transfer tube of the condenser 63 in the height direction. By providing this opening 39A, as explained below, the regenerated processing liquid L1 can be easily separated from the unregenerated processing liquid L1 within the regeneration device 20.

[0065] <Gas Treatment Methods, Regeneration Methods>

[0066] Next, the gas treatment method and regeneration method according to this embodiment will be described. In this method, the treatment liquid L1 absorbs acidic compounds (e.g., CO2) contained in the gas being treated in the following manner, and the acidic compounds are released from the treatment liquid L1 by heating.

[0067] First, in the absorption device 10, the gas to be treated, containing an acidic compound, comes into contact with the treatment liquid L1. Accordingly, the acidic compound is absorbed by the treatment liquid L1, and the treatment liquid L1 undergoes phase separation. Specifically, with the treatment liquid L1 stored in the storage space S9 of the absorption device 10, the gas to be treated is supplied from the gas supply unit 17 to the first space S3.

[0068] Accordingly, the bubbly gas being treated comes into contact with the treatment liquid L1, and the acidic compounds in the gas are absorbed by the treatment liquid L1. Specifically, when the acidic compound is CO2 and the treatment liquid L1 contains a primary amine, such as 2RNH2 + CO2 → RNH3. + +RNHCOO - As shown in the reaction equation, the CO2 absorption reaction occurs. In addition, since the gas being treated contains not only acidic compounds such as CO2, but also other gaseous components such as nitrogen, the stirring effect of the treatment liquid L1, achieved by the gas being treated in the form of bubbles, is maintained even as the absorption of acidic compounds progresses.

[0069] Accordingly, the processing liquid L1 is separated in the first space S3 into a first liquid phase (e.g., an amine phase) with a high content of acidic compounds and a second liquid phase (e.g., an ether phase) with a low content of acidic compounds. In this embodiment, the specific gravity decreases in the order of the first liquid phase and the second liquid phase.

[0070] The lighter second liquid phase overflows from the upper end of the first wall portion 18 and flows into the second space S4, while the heavier first liquid phase flows into the second space S4 through the opening G1 of the first wall portion 18. Furthermore, the second liquid phase overflows from the upper end of the second wall portion 19 and flows into the third space S5.

[0071] In this way, the first liquid phase and the second liquid phase of the treatment liquid L1 can be separated within the container 13. Furthermore, the first liquid phase flows out from the first outlet 25 to the first branch 31A, and the second liquid phase flows out from the second outlet 26 to the second branch 31B. Accordingly, the volumetric flow ratio of the two liquid phases in the treatment liquid L1 delivered to the regeneration device 20 can be maintained at a constant value.

[0072] Next, the phase-separated treatment liquid L1 is transported from the absorption unit 10 to the regeneration unit 20. Specifically, the first liquid phase portion and the second liquid phase portion are transported to the regeneration unit 20 by pumps 53 and 33. At this time, the two liquid phase portions are mixed in the middle of the first flow path 31 (the confluence point of the first branch 31A and the second branch 31B), becoming a two-phase state before flowing into the regeneration unit 20. In addition, the treatment liquid L1 before regeneration is heated in the heat exchanger 40 by heat exchange with the regenerated treatment liquid L1 before flowing into the regeneration unit 20.

[0073] Next, the treatment liquid L1 is heated in the regeneration device 20, and the treatment liquid L1, after releasing acidic compounds through heating, is extracted from the regeneration device 20 and returned to the absorption device 10. In this regeneration step, the regeneration method according to this embodiment, as described below, is performed.

[0074] In this regeneration method, firstly, the treatment liquid L1, which has undergone phase separation by absorbing acidic compounds, is supplied from the first flow path 31 to the first space S12 within the container 35. Specifically, the treatment liquid L1, which will be in a two-phase state, is ejected from the nozzle outlet of the treatment liquid supply unit 38 to the heating zone R1.

[0075] Next, the treatment liquid L1 supplied to the heating zone R1 is heated by heat exchange with the refrigerant flowing through the condenser 63, thereby releasing the acidic compound from the treatment liquid L1. The treatment liquid L1 after the release of the acidic compound is mainly located between the first liquid phase (e.g., the amine phase) and the second liquid phase (e.g., the ether phase). At this time, in the heating zone R1, the treatment liquid L1 is stirred by bubbles of the released acidic compound or by jets of the treatment liquid L1, whereas stirring is difficult to occur in the settling zone R2.

[0076] Therefore, the treatment liquid L1 after releasing the acidic compound accumulates in the settling zone R2 without being affected by stirring. Accordingly, in the settling zone R2, since the height of the regenerated treatment liquid L1 is stable, it remains stationary at a position approximately equal to the height of the opening 39A. Furthermore, the regenerated treatment liquid L1 flows from the settling zone R2 of the first space S12 into the second space S13 through the opening 39A. Thereafter, the regenerated treatment liquid L1 flows out of the regeneration device 20 from the outlet 42 and returns to the absorption device 10 via the second flow path 32.

[0077] As described above, in this embodiment, the process liquid L1 in a phase-separated state is regenerated by heating it in the regeneration device 20 to release acidic compounds. During this regeneration process, since the process liquid L1 is stirred and mixed using gaseous acidic compounds (e.g., CO2) released from it, the contact interface between the first liquid phase (e.g., amine phase) and the second liquid phase (e.g., ether phase) increases, promoting the release of acidic compounds. Furthermore, in this embodiment, after the regenerated process liquid L1 has released the acidic compounds and accumulated in the settling area R2, it can flow into the second space S13 through the opening 39A of the first wall portion 39. Therefore, the regenerated process liquid L1 can be easily separated from the unregenerated process liquid L1, and the regenerated process liquid L1 can be selectively extracted from the regeneration device 20.

[0078] (Second Implementation)

[0079] based on Figure 4 The regeneration apparatus 20A according to the second embodiment will be described. The regeneration apparatus 20A according to the second embodiment has basically the same structure and performs the same effect as the regeneration apparatus 20 according to the first embodiment, but the position of the processing liquid supply unit 38 is different. Hereinafter, only the differences from the first embodiment will be described.

[0080] In the second embodiment, the processing liquid supply unit 38 is disposed on the top side of the container 35. Specifically, the processing liquid supply unit 38 is located above the liquid surface of the processing liquid L1, and is disposed in the container 35 with the nozzle outlet facing downward (towards the heat transfer tube side of the condenser 63). In this embodiment, the processing liquid L1 can be stirred and mixed by utilizing the impact of the jet of processing liquid L1 on the liquid surface.

[0081] (Third Implementation)

[0082] based on Figure 5 The regeneration apparatus 20B according to the third embodiment will be described. The regeneration apparatus 20B according to the third embodiment has basically the same structure and performs the same effect as the regeneration apparatus 20A according to the second embodiment, but it differs from the second embodiment in that it has a second wall portion 43 and a return path 44. Hereinafter, only the differences from the second embodiment will be described.

[0083] The second wall portion 43 is vertically disposed at the bottom of the container 35, dividing the space within the container 35 into a second space S13 and a third space S14. The second wall portion 43 is substantially parallel to the first wall portion 39 and, when viewed from the first wall portion 39, is located on the opposite side of the tube sheet 36. That is, the second wall portion 43 is located on the opposite side of the heating section (condenser 63) relative to the first wall portion 39. The second wall portion 43 includes an upper end that allows liquid to overflow from the second space S13 to the third space S14, and this upper end is located on the lower side (bottom side of the container 35) relative to the upper end of the first wall portion 39.

[0084] Return path 44 is a path used to return liquid from the third space S14 to the first space S12. For example... Figure 5 As shown, the upstream end of the reflux path 44 is connected to the portion of the bottom of the container 35 facing the third space S14, and the downstream end is connected to a portion near the downstream end of the first flow path 31 (or a portion located downstream of the heat exchanger 40). Furthermore, an infusion pump 45 is provided in the reflux path 44.

[0085] According to the third embodiment, even if the second liquid phase portion, such as the ether phase, flows into the second space S13 through the opening 39A, it can be easily separated from the regenerated processed liquid L1 in the second space S13 by allowing the second liquid phase portion to overflow from the upper end of the second wall portion 43 into the third space S14. Furthermore, by returning the second liquid phase portion overflowing into the third space S14 to the first space S12 through the return path 44, changes in the ratio of each liquid phase portion (e.g., the ratio of the ether phase to the amine phase) in the processed liquid L1 before regeneration can be suppressed. Additionally, in this embodiment, as... Figure 3 As shown, the processing liquid supply unit 38 can also be configured on the bottom side of the container 35.

[0086] (Fourth Implementation)

[0087] Next, based on Figure 6 The regeneration apparatus 20C according to the fourth embodiment will be described. The regeneration apparatus 20C according to the fourth embodiment has basically the same structure and performs the same effect as the regeneration apparatus 20B according to the third embodiment, but the position of the opening 39A in the first wall portion 39 is different from that in the third embodiment. Hereinafter, only the differences from the third embodiment will be described.

[0088] like Figure 6 As shown, in the fourth embodiment, the opening 39A is formed at the lowest point in the height direction of the first wall portion 39. In this case, the regenerated treatment liquid L1 can also flow from the first space S12 to the second space S13 through the opening 39A.

[0089] In the first space S12, the pre-regeneration liquid phases (e.g., ether and amine phases) of the regenerated liquid L1 exist above and below it. However, if the supply of liquid L1 to the regeneration device 20 is significantly less, a heavier liquid phase (e.g., amine phase) may not be present below the regenerated liquid L1. In this case, since the regenerated liquid L1 is located near the bottom of the container 35, it can flow into the second space S13 through the opening 39A formed at the bottommost part.

[0090] Furthermore, in the fourth embodiment, such as Figure 3 As shown, the processing fluid supply unit 38 can also be located on the bottom side of the container 35. Furthermore, the second wall 43, the return path 44, and the infusion pump 45 can be omitted.

[0091] The embodiments disclosed herein are illustrative at all points and should not be construed as limiting. The scope of the invention is defined not by the description but by the claims, and includes all modifications within the meaning and scope equivalent to the claims. Therefore, the following embodiments are also included within the scope of the invention.

[0092] The embodiment is not limited to an absorption device 10 having a container 13 that is placed horizontally as a can, for example... Figure 7 As shown, an absorption device 10A with a tower-shaped container 71 can also be used. In this case, the gas supply path 11 is connected to the lower part of the container 71, and the gas discharge path 12 is connected to the top of the container 71. In addition, each branch of the first flow path 31 (first branch 31A, second branch 31B) is connected to the bottom of the container 71, and the second flow path 32 is connected to the upper part of the container 71.

[0093] A second wall 19 is vertically provided on the bottom surface of container 71, dividing it into a second space S4 and a third space S5. Furthermore, a cover member 19A is provided to cover the third space S5 from above. Inside container 71, the treatment liquid L1 supplied from the second flow path 32 flows down, and the treatment liquid L1 that absorbs acidic compounds and flows down to the bottom of the tower is stored in the second space S4. Subsequently, the first liquid phase, which has a lower specific gravity, overflows from the upper end of the second wall 19 into the third space S5, thereby separating the first liquid phase from the second liquid phase. Then, each liquid phase is drawn from the absorption device 10A through the first branch 31A and the second branch 31B, and its flow rate is regulated and transported to the regeneration device 20.

[0094] In addition, it can also be like Figure 8Similar to the absorption device 10B, the separation tank 72 for the processed liquid L1 is disposed on the lower side of the container 71, and the separation tank 72 is connected to the bottom of the container 71 via the recovery path 73. Alternatively, a second wall 19 may be erected vertically from the bottom inside the separation tank 72, dividing the space inside the bottom into a second space S4 and a third space S5. In this case, the processed liquid L1 that absorbs acidic compounds and flows into the separation tank 72 is stored in the second space S4 of the separation tank 72, and the first liquid phase portion (upper phase portion) of the processed liquid L1 overflows from the upper end of the second wall 19 into the third space S5. Then, each liquid phase portion is drawn from the separation tank 72 through the first branch 31A and the second branch 31B, and its flow rate is adjusted and transported to the regeneration device 20.

[0095] like Figures 9-12 As shown, the first wall portion 39 of the regeneration device may also include a pair of wall members (first wall member 81, second wall member 82), in which case the opening 39A is formed by the gap between the two wall members. Figure 9 In the container 35, the first wall member 81 is erected at the bottom of the container 35, and the second wall member 82 is disposed at a distance from the bottom of the container 35 on the rear side of the first wall member 81 (opposite side of the condenser 63), and the upper end of the first wall member 81 and the lower end of the second wall member 82 partially overlap in the height direction. Figure 10 yes Figure 9 The diagram shows the positions of the first wall member 81 and the second wall member 82 interchanged. That is, in Figure 10 In the container 35, the first wall member 81 is erected at the bottom of the container 35, and the second wall member 82 is disposed in front of the first wall member 81 (closer to the condenser 63 than the first wall member 81) with a gap between it and the bottom of the container 35. The upper end of the first wall member 81 and the lower end of the second wall member 82 partially overlap in the height direction. Figure 11 yes Figure 9 The diagram shows two wall members arranged so that their ends do not overlap. Figure 12 yes Figure 10 The diagram shows two wall members arranged so that their ends do not overlap.

[0096] In the first embodiment, an example is shown where the opening 39A is formed at the central portion in the height direction of the first wall portion 39 or at a portion located on the bottom side of the container 35 relative to the central portion, but it is not limited to this. Figure 13As shown, the opening 39A may also be formed in the central portion C1 in the height direction of the first wall portion 39 or in a portion located on the upper side (opposite to the bottom of the container 35) relative to the central portion C1. According to this structure, when the regenerated treatment liquid L1 is located on the upper side of the first wall portion 39 according to the composition of the treatment liquid L1 or the position of the liquid level, the regenerated treatment liquid L1 can also flow into the second space S13.

[0097] In the first embodiment, the case where a heat pump 60 is provided in the gas processing device 1 has been described, but the heat pump 60 may also be omitted. In this case, the heating section of the condenser 63, which replaces the heat pump 60, may also use a structure that uses any heat source such as electricity, steam or a burner to heat the processing liquid L1 drawn from the regeneration device 20 to the outside.

[0098] Here, the implementation method is described in summary.

[0099] One aspect of the present invention relates to a regeneration apparatus for regenerating a treatment liquid that is in a phase-separated state by absorbing an acidic compound, thereby releasing the acidic compound. The regeneration apparatus includes: a container for containing the treatment liquid; and a first wall dividing the space within the container into a first space and a second space. The first space includes: a heating zone receiving the treatment liquid supplied from outside the container and equipped with a heating element for heating the treatment liquid; and a settling zone receiving the treatment liquid from the heating zone after the acidic compound has been released by heating with the heating element. The second space is a space capable of discharging the treatment liquid after the release of the acidic compound to the outside of the container. An opening is formed in the first wall to allow the treatment liquid in the settling zone to flow into the second space.

[0100] In this regeneration apparatus, acidic compounds can be released by heating the phase-separated processing liquid, thereby regenerating the processing liquid. During this regeneration process, in the heating zone, the processing liquid is stirred and mixed using the acidic compounds released from it, thus increasing the contact interface between the first and second liquid phases. Consequently, the release of acidic compounds from the processing liquid is promoted, enabling the removal of acidic compounds from the treated gas. Furthermore, in this apparatus, after the regenerated processing liquid containing the released acidic compounds is temporarily placed in a settling zone, it can flow into a second space through an opening in the first wall. This allows for easy separation of the regenerated processing liquid from the unregenerated processing liquid, and selective extraction of the regenerated processing liquid from the unregenerated processing liquid.

[0101] (2) In the above-described regeneration apparatus, the first wall portion may be erected at the bottom of the container. The opening may be formed at the central portion in the height direction of the first wall portion or at a portion located on the bottom side relative to the central portion.

[0102] According to this structure, since the height of the opening in the first wall is close to the height of the regenerated treatment liquid, the regenerated treatment liquid can easily flow into the second space.

[0103] (3) In the above-described regeneration device, the opening may be formed at the lowest part of the first wall portion in the height direction.

[0104] In the first space within the container, the various liquid phases of the pre-regeneration treatment liquid are usually present. However, if the supply of treatment liquid to the container is significantly low, a clear liquid-liquid interface between the two phases may not form in the first space. Based on the above structure, even in this case, the regenerated treatment liquid can easily flow into the second space.

[0105] (4) In the above-described regeneration device, the first wall portion may be erected at the bottom of the container. The opening may be formed at the central portion in the height direction of the first wall portion or at the upper end relative to the central portion.

[0106] According to this structure, even if the regenerated treatment liquid is located at the center or upper side of the first wall in the height direction, depending on the composition of the treatment liquid or the liquid level, the regenerated treatment liquid can be easily allowed to flow into the second space.

[0107] (5) The above-mentioned regeneration device may also include: a processing liquid supply unit for supplying the processing liquid to the heating zone. The processing liquid supply unit may be disposed on the bottom side or the top side of the container.

[0108] According to this structure, the processing liquid stored in the container can be effectively stirred and mixed. Specifically, when the processing liquid supply unit is disposed at the bottom of the container, the processing liquid is supplied from the inside of the processing liquid accumulated in the container, thus stirring and mixing the processing liquid by utilizing the flow action at this time. Accordingly, the contact interface between the first liquid phase and the second liquid phase can be increased. On the other hand, when the processing liquid supply unit is disposed at the top of the container, the processing liquid can be stirred and mixed by utilizing the action of supplying the processing liquid to the surface of the processing liquid.

[0109] (6) In the above-described regeneration apparatus, the heating section may include a heat transfer tube in which a heating medium for heat exchange with the processing liquid flows and is disposed in the heating zone. The processing liquid supply section may be provided with a supply port for supplying the processing liquid to the heat transfer tube.

[0110] Based on this structure, heat transfer from the heating medium to the treatment liquid is easily achieved, which can promote the regeneration of the treatment liquid.

[0111] (7) The above-mentioned regeneration device may also further include: a second wall portion that divides the space within the container into a second space and a third space. The second wall portion may be erected at the bottom of the container and includes an end portion that allows liquid to overflow from the second space to the upper part of the third space.

[0112] According to this structure, even if the liquid phase with a smaller specific gravity in the pre-regeneration treatment liquid (phase separation liquid) flows into the second space, it can be easily separated from the post-regeneration treatment liquid by allowing the liquid phase to overflow into the third space.

[0113] (8) The above-mentioned regeneration device may also include: a return path for returning liquid from the third space to the first space.

[0114] According to this structure, by returning the liquid phase portion that overflows into the third space to the first space through a reflux path, it is possible to suppress changes in the ratio of each liquid phase portion in the pre-regeneration treatment liquid (phase separation liquid).

[0115] (9) The gas treatment apparatus according to the embodiment includes: an absorption device, which causes the treatment liquid to absorb acidic compounds contained in the gas being treated by contacting the gas being treated with the treatment liquid; and the above-mentioned regeneration device.

[0116] (10) The regeneration method involved in the embodiment includes the following steps: supplying a treatment liquid that has been phase-separated by absorbing an acidic compound to a first space in a container; releasing the acidic compound from the treatment liquid by heating the treatment liquid supplied to the first space; and allowing the treatment liquid after releasing the acidic compound to temporarily remain in the first space, and then allowing the treatment liquid to flow from the first space into the second space through an opening formed in the wall separating the first space and the second space.

[0117] According to this method, the treatment liquid is stirred and mixed using acidic compounds released from it through heating, increasing the contact interface between the first liquid phase and the second liquid phase, thereby promoting the release of the acidic compounds. Furthermore, after the treatment liquid containing the released acidic compounds is left to stand in the first space, it flows from the first space into the second space through an opening in the wall, thereby easily separating the regenerated treatment liquid from the unregenerated treatment liquid and selectively extracting the regenerated treatment liquid.

[0118] Another aspect of the present invention relates to a gas treatment method comprising the following steps: contacting a gas to be treated containing an acidic compound with a treatment liquid in an absorption device, thereby causing the treatment liquid to absorb the acidic compound and thus separating the phases of the treatment liquid; conveying the phase-separated treatment liquid from the absorption device to a regeneration device; and performing the above-described regeneration method in the regeneration device to extract the treatment liquid after the release of the acidic compound from the regeneration device and return it to the absorption device.

[0119] As explained above, a regeneration apparatus and method that can promote the release of acidic compounds and selectively extract the regenerated treatment liquid, a gas treatment apparatus equipped with the regeneration apparatus, and a gas treatment method for performing the regeneration method can be provided.

Claims

1. A regeneration apparatus for regenerating a treatment liquid that is in a phase-separated state due to the absorption of an acidic compound by heating it, thereby releasing the acidic compound and regenerating the treatment liquid, characterized in that... include: Container, containing the treatment liquid; as well as The first wall divides the space inside the container into a first space and a second space, wherein... The aforementioned container is a horizontally placed can. The first space includes: a heating zone that receives the phase-separated processing liquid supplied from outside the container and is equipped with a heating unit for heating the phase-separated processing liquid; and a settling zone located to the side of the heating zone and adjacent to the second space, and receiving the processing liquid after the acidic compound has been released by heating by the heating unit and the phase-separated processing liquid from the heating zone. In the heating zone, the treatment liquid is stirred by the release of bubbles of the acidic compound or by a jet of the treatment liquid; in the settling zone, the treatment liquid is difficult to stir. The second space is a space capable of draining the treatment liquid after the release of the acidic compound to the outside of the container. The treatment liquid in a phase-separated state comprises: a first liquid phase portion; and a second liquid phase portion, wherein the acidic compound has a lower content and lower specific gravity than the first liquid phase portion. The treatment solution, after releasing the acidic compound, is located between the first liquid phase portion and the second liquid phase portion in the settling area. An opening is formed in the first wall portion at a location where the treatment liquid, after releasing the acidic compound from the treatment liquid in the settling area, flows into the second space.

2. The regeneration device according to claim 1, characterized in that: The first wall portion is vertically disposed at the bottom of the container. The opening is formed in the central portion of the first wall portion in the height direction or in the portion located on the bottom side relative to the central portion.

3. The regeneration device according to claim 2, characterized in that: The opening is formed at the lowest point in the height direction of the first wall portion.

4. The regeneration device according to claim 1, characterized in that: The first wall portion is vertically disposed at the bottom of the container. The opening is formed in the first wall portion at the upper end relative to the central portion in the height direction.

5. The regeneration device according to claim 1, characterized in that... Also includes: The processing fluid supply unit supplies the processing fluid to the heating zone. The processing fluid supply unit is located on the bottom or top side of the container.

6. The regeneration device according to claim 5, characterized in that: The heating unit includes a heat transfer tube disposed in the heating zone, through which a heating medium flows to exchange heat with the processing liquid. The processing liquid supply section is provided with a supply port for supplying the processing liquid to the heat transfer pipe.

7. The regeneration device according to claim 1, characterized in that... Also includes: The second wall portion separates the second space and the third space within the container. The second wall is erected at the bottom of the container and includes an upper end that allows liquid to overflow from the second space to the third space.

8. The regeneration device according to claim 7, characterized in that... Also includes: A return path is provided to allow liquid to flow back from the third space to the first space.

9. A gas processing device, characterized in that... include: An absorption device that brings the gas to be treated into contact with a treatment liquid, causing the treatment liquid to absorb the acidic compounds contained in the gas to be treated; as well as The regeneration device according to any one of claims 1 to 8.

10. A regeneration method, characterized in that... Includes the following steps: Prepare a container for use as a horizontal can; The treatment liquid, which is in a phase-separated state by absorbing acidic compounds, is supplied to the first space within the container; The acidic compound is released from the treatment liquid by heating the treatment liquid supplied to the first space in the heating zone within the first space; as well as After the treatment liquid after releasing the acidic compound and the treatment liquid in a phase-separated state are temporarily retained in the static area located on the side of the heating zone in the first space, the treatment liquid after releasing the acidic compound flows from the first space into the second space through an opening formed in the wall separating the first space and the second space. In the heating zone, the treatment liquid is stirred by the release of bubbles of the acidic compound or by a jet of the treatment liquid; in the settling zone, the treatment liquid is difficult to stir. The processing liquid in a phase-separated state comprises: a first liquid phase portion; And a second liquid phase, wherein the acidic compound is present in a lower concentration and has a lower specific gravity than the first liquid phase. The treatment liquid after the release of the acidic compound is located between the first liquid phase portion and the second liquid phase portion in the settling area.

11. A gas treatment method, characterized in that... Includes the following steps: The treatment liquid phase is separated by contacting the gas containing acidic compounds with the treatment liquid in an absorption device, causing the treatment liquid to absorb the acidic compounds. The treated liquid after phase separation is transported from the absorption device to the regeneration device; as well as The regeneration method of claim 10 is implemented in the regeneration device, wherein the treated liquid after the release of the acidic compound is extracted from the regeneration device and returned to the absorption device.

Images