Gas processing device and gas processing method

Abstract

To prevent dilution of processing liquid with water in a gas processing device that separates acidic compounds from processing object gas using the processing liquid that contains amine.SOLUTION: A gas processing device 10 includes: an absorber 12 that brings processing object gas containing acidic compounds into contact with processing liquid that is in such a state that amine and the second component are mixed in a state before absorbing the acidic compounds and performs phase separation of the acidic compounds into the first phase portion mainly containing amine and the second phase portion mainly containing the second component through absorption of the acidic compounds, and makes the acidic compounds contained in the processing object gas absorbed by the processing liquid; a regenerator 14 that separates the acidic compounds from the processing liquid; and a processing liquid recovery unit 42 that brings the second phase portion discharged from the absorber 12 into contact with the processing liquid entrained gas inside the absorber 12 to recover the processing liquid entrained in the processing liquid entrained gas.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas processing apparatus and a gas processing method. [Background technology]

[0002] In recent years, carbon dioxide is considered to have a large impact on global warming. As an effective measure against this global warming problem, a technology for recovering CO2 from a large volume of gas containing carbon dioxide (CO2) (CO2-containing gas) has been attracting attention. There are various methods for recovering CO2, for example, chemical absorption methods such as amine absorption method. The chemical absorption method is a method in which an alkaline aqueous solution such as an amine aqueous solution is used as a treatment liquid, a CO2-containing gas is contacted with this treatment liquid to absorb acidic compounds (CO2) into the treatment liquid, and the treatment liquid that has absorbed the acidic compounds is heated to release the acidic compounds from the treatment liquid and recover the acidic compounds. A chemical absorption method using a treatment liquid containing an amine compound is disclosed, for example, in Patent Document 1 below. In the gas treatment device disclosed in Patent Document 1, a treatment liquid containing an amine compound, an organic solvent, and water is used, and a treatment liquid that absorbs acidic compounds and thereby separates into phases with different acidic compound contents is selected as the treatment liquid. In addition, the gas treatment device disclosed in Patent Document 1 is provided with a gas supply unit that supplies a separation promotion gas such as hydrogen gas to a regenerator. In this device, a separation-promoting gas is supplied to the regenerator, thereby reducing the energy required to separate and recover acidic compounds.

[0003] In the amine absorption method using such a treatment liquid containing an amine compound, it is known that the amine compound is entrained in the treated gas after the acidic compounds are separated, as disclosed in the following Patent Document 2. In order to prevent the amine compound from being entrained in the treated gas and released to the outside of the system, the gas treatment device disclosed in Patent Document 2 is provided with a water washing section in the absorber that brings the decarbonated flue gas from which CO2 has been removed into contact with wash water to remove substances entrained in the decarbonated flue gas. When the amine compound is entrained in the treated gas, it may be entrained as an evaporated gas or as a mist (liquid). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6906766 [Patent Document 2] Patent No. 5968159 Summary of the Invention [Problem to be solved by the invention]

[0005] When a water washing section is provided in the absorber as in the gas treatment device disclosed in Patent Document 2, it is possible to prevent the amine compound from being discharged outside the system. However, since the treatment liquid comes into contact with the wash water, there is a problem in that the treatment liquid circulating between the absorber and the regenerator becomes diluted.

[0006] On the other hand, in the case where hydrogen gas, for example, is supplied to the regenerator as the separation promoting gas as in the gas treatment device disclosed in Patent Document 1, when the hydrogen gas is obtained by water electrolysis, moisture close to saturation may be retained in the hydrogen gas. In this case, the moisture retained in the hydrogen gas is supplied to the regenerator, which causes a problem that the treatment liquid circulating between the absorber and the regenerator becomes diluted.

[0007] As in the gas treatment devices disclosed in Patent Documents 1 and 2, if the treatment liquid circulating between the absorber and the regenerator becomes diluted, there is a risk that the performance of the treatment liquid in separating acidic compounds will decrease.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned conventional technology, and an object of the present invention is to prevent the treatment liquid from being diluted with water in a gas treatment device or gas treatment method in which an amine-containing treatment liquid is used to separate acidic compounds from a gas to be treated. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the gas treatment apparatus according to the present invention includes an absorber that brings into contact with a gas to be treated, which contains an acidic compound that generates an acid when dissolved in water, and a treatment liquid that is in a state in which an amine and a second component are mixed before absorbing the acidic compound and that phase-separates into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, the gas to be treated being absorbed into the treatment liquid, a regenerator that heats the treatment liquid that has absorbed the acidic compound and separates the acidic compound from the treatment liquid, and a treatment liquid recovery section that brings at least one of the first phase portion and the second phase portion flowing out from the absorber into contact with a treatment liquid-accompanying gas, which is the gas in the absorber after the acidic compound from the gas to be treated is absorbed into the treatment liquid or the gas in the regenerator containing the acidic compound, and recovers the treatment liquid entrained in the treatment liquid-accompanying gas.

[0010] In the gas treatment device of the present invention, at least one of the first phase portion and the second phase portion flowing out from the absorber is contacted with the treated liquid-accompanying gas in the treated liquid recovery section. At this time, when the first phase portion mainly containing amine is contacted with the treated liquid-accompanying gas, the amine in the first phase portion is likely to mix with the second component entrained in the treated liquid-accompanying gas. Therefore, the second component entrained in the treated liquid-accompanying gas can be recovered. On the other hand, when the second phase portion mainly containing the second component is contacted with the treated liquid-accompanying gas, the second component in the second phase portion is likely to mix with the amine entrained in the treated liquid-accompanying gas. Therefore, the amine entrained in the treated liquid-accompanying gas can be recovered. At this time, if washing water is not used to wash the treated liquid entrained in the treated liquid-accompanying gas, the treated liquid will not be diluted. On the other hand, even if washing with washing water is used in combination, the amount of washing water can be reduced, so that the treated liquid can be prevented from being diluted. Therefore, it is possible to suppress a decrease in the performance of separating and recovering acidic compounds via the treatment liquid.

[0011] The gas treatment device may include a separator that separates the treatment liquid that has absorbed the acidic compound into a treatment liquid mainly containing the first phase portion and a treatment liquid mainly containing the second phase portion.

[0012] In this embodiment, the treated liquid separated in the separator (i.e., the treated liquid separated into the treated liquid mainly containing the first phase portion and the treated liquid mainly containing the second phase portion) comes into contact with the treated liquid-accompanying gas in the treated liquid recovery section. Therefore, the treated liquid entrained in the treated liquid-accompanying gas can be effectively recovered.

[0013] The gas treatment device may include a water washing section that brings the treated-liquid-accompanying gas and wash water into contact with each other to recover the treated liquid entrained in the treated-liquid-accompanying gas. In this case, the treated-liquid recovery section may be disposed at a position where the absorption liquid that has been phase-separated into the first phase and the second phase comes into contact with the treated-liquid-accompanying gas before coming into contact with the wash water in the water washing section.

[0014] In this embodiment, at least one of the first phase portion and the second phase portion is used for contact with the treatment liquid-accompanying gas in the treatment liquid recovery section, and therefore at least one of the first phase portion and the second phase portion is entrained in the treatment liquid-accompanying gas. After that, the treatment liquid-accompanying gas comes into contact with the wash water in the water washing section. Therefore, at least one of the first phase portion and the second phase portion entrained in the treatment liquid-accompanying gas is recovered. Therefore, in the treatment liquid recovery section, the treatment liquid entrained in the treatment liquid-accompanying gas can be recovered, and at least one of the first phase portion and the second phase portion used in the treatment liquid recovery section and entrained in the treatment liquid-accompanying gas can also be recovered.

[0015] The gas treatment device may include a separation promoting gas supplying section that supplies a separation promoting gas consisting of a gas or water vapor that is almost insoluble and inactive in the treatment liquid to the regenerator. In this case, the treatment liquid recovery section is configured to contact at least one of the first phase portion and the second phase portion flowing out from the absorber with a pretreatment liquid-accompanying gas.

[0016] In this embodiment, the regeneration temperature can be lowered because a separation promoting gas is fed to the regenerator, thus allowing the use of lower temperature (lower quality) heat.

[0017] In the gas treatment device, the treated liquid recovery section may be configured to contact at least one of the first phase portion and the second phase portion flowing out from the absorber with a gas containing the acidic compound in the regenerator.

[0018] In this embodiment, the separation promoting gas is supplied to the regenerator by the separation promoting gas supply unit, so the amount of gas in the regenerator is large. Accordingly, the amount of treated liquid entrained in the treated liquid-accompanying gas also increases. However, since at least one of the first phase portion and the second phase portion flowing out from the absorber is introduced into the regenerator, even if the amount of treated liquid entrained in the treated liquid-accompanying gas in the regenerator increases, the entrained treated liquid can be effectively recovered.

[0019] In the gas treatment device, the separation-promoting gas may be a gas containing moisture or a gas consisting of water vapor. In this case, the gas treatment device may include a moisture removal unit that separates moisture contained in the separation-promoting gas from the separation-promoting gas supplied to the regenerator.

[0020] In this embodiment, the moisture is removed from the separation-promoting gas, which is a gas containing moisture or a gas composed of water vapor, in the moisture removing section. Therefore, not only can the regeneration temperature be lowered, but also dilution of the treatment liquid by the separation-promoting gas can be suppressed.

[0021] In the gas treatment device, the separation promoting gas may be a gas containing moisture or a gas consisting of water vapor. In this case, the gas treatment device may include a moisture removing section that separates moisture contained in the separation promoting gas from the separation promoting gas supplied to the regenerator, and a moisture supply path that supplies the moisture obtained in the moisture removing section to at least one of the water washing section of the absorber, the water washing section of the regenerator, a condenser provided in a supply path for supplying the acidic compound obtained in the regenerator to a destination, and a condenser provided in a discharge path for discharging the treated gas from the absorber.

[0022] In this embodiment, the moisture obtained in the moisture removing section is supplied through a moisture supply passage to at least one of the water washing section of the absorber, the water washing section of the regenerator, the condenser provided in the supply passage, and the condenser provided in the discharge passage. Then, in the water washing section or the condenser, at least one of the treated liquid entrained in the gas in the regenerator and the treated liquid entrained in the treated gas discharged from the absorber is recovered. That is, the moisture obtained in the moisture removing section is used to recover the treated liquid entrained in the gas entrained with the treated liquid. Therefore, the moisture separated in the moisture removing section can be effectively utilized.

[0023] The gas treatment device of the present invention includes an absorber that brings into contact with a gas to be treated, which contains an acidic compound that produces an acid when dissolved in water, and a treatment liquid in which an amine and a second component are mixed before the acidic compound is absorbed and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, the absorber causing the acidic compound contained in the gas to be treated to be absorbed into the treatment liquid, a regenerator that heats the treatment liquid that has absorbed the acidic compound and separates the acidic compound from the treatment liquid, a separation promotion gas supplying section that supplies a separation promotion gas consisting of a gas that is almost insoluble and inactive in the treatment liquid and contains moisture and is water vapor to the regenerator, and a moisture removing section that removes moisture contained in the separation promotion gas from the separation promotion gas supplied to the regenerator.

[0024] In the gas treatment device according to the present invention, the regeneration temperature can be lowered by supplying a separation promotion gas to the regenerator. Therefore, it becomes possible to use lower temperature (low quality) heat. Moreover, in the moisture removal section, moisture is removed from the separation promotion gas, which is a gas containing moisture or a gas composed of water vapor, and then the gas is supplied to the regenerator. Therefore, it is possible to prevent the treatment liquid from being diluted by the separation promotion gas. Therefore, it is possible to prevent a decrease in the separation and recovery performance of acidic compounds via the treatment liquid.

[0025] In the gas treatment method according to the present invention, a gas to be treated containing an acidic compound that generates an acid when dissolved in water is brought into contact with a treatment liquid in an absorber, which is in a state in which an amine and a second component are mixed before the acidic compound is absorbed, and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, to absorb the acidic compound in the gas to be treated into the treatment liquid, and in a regenerator, the treatment liquid that has absorbed the acidic compound is heated to separate the acidic compound from the treatment liquid, and the first phase portion and the second phase portion are discharged from the absorber, and at least one of the first phase portion and the second phase portion discharged from the absorber is contacted with a treatment-liquid-accompanying gas, which is the gas in the absorber after the acidic compound from the gas to be treated is absorbed by the treatment liquid or the gas in the regenerator containing the acidic compound, to recover the treatment liquid entrained in the treatment-liquid-accompanying gas.

[0026] In the gas treatment method of the present invention, at least one of the first phase and the second phase flowing out from the absorber contacts the treated liquid-accompanying gas in the absorber or the regenerator. At this time, when the first phase mainly containing amine contacts the treated liquid-accompanying gas, the amine in the first phase is likely to mix with the second component entrained in the treated liquid-accompanying gas. Therefore, the second component entrained in the treated liquid-accompanying gas can be recovered. On the other hand, when the second phase mainly containing the second component contacts the treated liquid-accompanying gas, the second component in the second phase is likely to mix with the amine entrained in the treated liquid-accompanying gas. Therefore, the amine entrained in the treated liquid-accompanying gas can be recovered. At this time, if wash water is not used to wash the treated liquid entrained in the treated liquid-accompanying gas, the treated liquid will not be diluted. On the other hand, even if washing with wash water is used in combination, the amount of wash water can be reduced, so that the treated liquid can be prevented from being diluted. Therefore, it is possible to suppress a decrease in the performance of separating and recovering acidic compounds via the treatment liquid.

[0027] In the gas treatment method, the treatment liquid having absorbed the acidic compound may be separated into a treatment liquid mainly containing the first phase portion and a treatment liquid mainly containing the second phase portion by a separator.

[0028] In this embodiment, at least one of the treated liquids separated in the separator (i.e., the treated liquid mainly containing the first phase portion and the treated liquid mainly containing the second phase portion) is contacted with the treated liquid-accompanying gas. That is, the treated liquid mainly containing the first phase portion or the second phase portion is used for contact with the treated liquid-accompanying gas. Therefore, the treated liquid entrained in the treated liquid-accompanying gas can be effectively recovered.

[0029] In the gas treatment method, the absorption liquid that has been phase-separated into the first phase portion and the second phase portion may be contacted with the treated liquid-entrained gas, and then the gas in the absorber or the gas in the regenerator may be contacted with wash water to recover the treated liquid entrained in the gas to be treated.

[0030] In this embodiment, at least one of the first phase portion and the second phase portion is used for contact with the treatment liquid-accompanying gas, and therefore at least one of the first phase portion and the second phase portion may be partially entrained in the treatment liquid-accompanying gas. Then, the treatment liquid-accompanying gas comes into contact with the cleaning water, and at least one of the first phase portion and the second phase portion entrained in the treatment liquid-accompanying gas is recovered. Therefore, at least one of the first phase portion and the second phase portion used for contact with the treatment liquid-accompanying gas and entrained in the treatment liquid-accompanying gas can also be partially recovered.

[0031] In the gas treatment method, a separation-promoting gas consisting of a gas or water vapor having almost no solubility and no reactivity in the treatment liquid may be supplied to the regenerator, and at least one of the first phase portion and the second phase portion flowing out from the absorber may be contacted with the treatment liquid-accompanying gas.

[0032] In this embodiment, by supplying the separation promoting gas to the regenerator, it is possible to reduce the energy required for separating the acidic compounds from the treatment liquid.

[0033] In the gas treatment method, at least one of the first phase portion and the second phase portion flowing out from the absorber may be contacted with a gas containing the acidic compound in the regenerator.

[0034] In this embodiment, the separation promoting gas is supplied to the regenerator by the separation promoting gas supply unit, so the amount of gas in the regenerator is large. Accordingly, the amount of treated liquid entrained in the treated liquid-accompanying gas also increases. However, since at least one of the first phase portion and the second phase portion flowing out from the absorber is introduced into the regenerator, even if the amount of treated liquid entrained in the treated liquid-accompanying gas in the regenerator increases, the entrained treated liquid can be effectively recovered.

[0035] In the gas treatment method, the separation-promoting gas may be a gas containing moisture or a gas consisting of water vapor. In this case, the moisture contained in the separation-promoting gas may be separated from the separation-promoting gas supplied to the regenerator, and the separated moisture may be brought into contact with the treatment liquid-accompanying gas to recover the treatment liquid entrained in the treatment liquid-accompanying gas.

[0036] In this embodiment, moisture is removed from the separation-promoting gas, which is a gas containing moisture or a gas composed of water vapor, and then the gas is supplied to the regenerator. Therefore, not only can the regeneration temperature be lowered, but also dilution of the treatment liquid by the separation-promoting gas can be suppressed. Meanwhile, the separated moisture is used to recover the treatment liquid entrained in the treatment-liquid-accompanying gas upon contact with the treatment-liquid-accompanying gas. Therefore, the separated moisture can be effectively utilized.

[0037] In the gas treatment method, moisture contained in the separation-promoting gas supplied to the regenerator may be separated from the separation-promoting gas, and the separated moisture may be supplied to at least one of the water washing section of the absorber, the water washing section of the regenerator, a condenser provided in a supply path for supplying the acidic compounds obtained in the regenerator to a destination, and a condenser provided in a discharge path for discharging the treated gas after treatment from the absorber.

[0038] In this embodiment, the separated moisture is supplied to at least one of the water washing section of the absorber, the water washing section of the regenerator, a condenser provided in the supply line, and a condenser provided in the discharge line. In the condenser, at least one of the treated liquid entrained with the acidic compounds obtained in the regenerator and the treated gas discharged from the absorber is recovered. Therefore, the separated moisture can be effectively utilized.

[0039] In the gas treatment method, at least one of the following may be measured: a concentration of sulfur contained in the gas to be treated introduced into the absorber; a flow rate of the gas to be treated introduced into the absorber; a concentration of amine or second component contained in the treated gas discharged from the absorber; a concentration of amine or second component contained in the gas containing acidic compounds discharged from the regenerator; and a concentration of deteriorated components contained in the treatment liquid introduced into the absorber; and based on a result of the measurement, at least one of the flow rate of water separated from the separation promoting gas and brought into contact with the treatment liquid-accompanying gas, the flow rate of the first phase portion or the second phase portion brought into contact with the treatment liquid-accompanying gas, and a flow rate of wash water supplied to a water washing section provided in at least one of the absorber and the regenerator may be adjusted.

[0040] In this embodiment, when the amount of evaporation or mist of the treatment liquid is large, or when the amount of evaporation or mist of the treatment liquid is expected to be large, the vapor or mist of the treatment liquid can be appropriately recovered.

[0041] In the gas treatment method, when a measurement result of at least one of the concentration of the amine or the second component contained in the treated gas discharged from the absorber and the concentration of the amine or the second component contained in the gas containing acidic compounds discharged from the regenerator becomes higher than a threshold value, at least one of the flow rate of the moisture separated from the separation promoting gas and to be contacted with the treated liquid-accompanying gas and the flow rate of the wash water supplied to the water washing section is increased, and when a measurement result of at least one of the concentration of the amine or the second component contained in the treated gas discharged from the absorber and the concentration of the amine or the second component contained in the gas containing acidic compounds discharged from the regenerator becomes lower than a threshold value, at least one of the flow rate of the moisture separated from the separation promoting gas and to be contacted with the treated liquid-accompanying gas and the flow rate of the wash water supplied to the water washing section is decreased.

[0042] In this embodiment, when the amount of evaporation or mist of the treatment liquid is large, the vapor or mist of the treatment liquid can be appropriately collected, whereas when the amount of evaporation or mist of the treatment liquid is small, the amount of water removed can be reduced, thereby reducing the energy required for removing the water.

[0043] In the gas treatment method, at least one of the following may be measured: the concentration of sulfur contained in the gas to be treated introduced into the absorber; the flow rate of the gas to be treated introduced into the absorber; the concentration of amine or second component contained in the treated gas discharged from the absorber; the concentration of amine or second component contained in the gas containing acidic compounds discharged from the regenerator; and the concentration of deteriorated components contained in the treatment liquid introduced into the absorber; and based on the results of the measurements, at least one of the flow rate of moisture separated from the separation-promoting gas and brought into contact with the treatment liquid-accompanying gas and the flow rate of the first phase portion or the second phase portion brought into contact with the treatment liquid-accompanying gas may be adjusted.

[0044] In this embodiment, when the amount of evaporation or mist of the treatment liquid is large, or when the amount of evaporation or mist of the treatment liquid is expected to be large, the vapor or mist of the treatment liquid can be appropriately recovered.

[0045] The gas treatment method of the present invention involves bringing into contact in an absorber a gas to be treated containing acidic compounds that produce acid when dissolved in water with a treatment liquid that undergoes phase separation into a first phase mainly containing an amine phase and a second phase mainly containing a component phase other than amines upon absorption of the acidic compounds, thereby causing the acidic compounds contained in the gas to be treated to be absorbed into the treatment liquid, and in a regenerator, heating the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid, removing moisture contained in the separation-promoting gas from a separation-promoting gas that is a gas that is almost insoluble and inactive in the treatment liquid and consists of a moisture-containing gas or water vapor, and supplying the separation-promoting gas from which the moisture has been removed to the regenerator.

[0046] In the gas processing method according to the present invention, the regeneration temperature can be lowered by supplying a separation promotion gas to the regenerator. Therefore, it becomes possible to use lower temperature (low quality) heat. Moreover, moisture is removed from the separation promotion gas, which is a gas containing moisture or a gas composed of water vapor, and then the gas is supplied to the regenerator. Therefore, it is possible to prevent the treatment liquid from being diluted by the separation promotion gas. Therefore, it is possible to prevent a decrease in the separation and recovery performance of acidic compounds via the treatment liquid. Effect of the Invention

[0047] As described above, according to the present invention, in a gas treatment device or gas treatment method in which an amine-containing treatment liquid is used to separate acidic compounds from a gas to be treated, it is possible to prevent the treatment liquid from being diluted with water. [Brief description of the drawings]

[0048] [Figure 1] 1 is a diagram illustrating a gas treatment device according to a first embodiment. [Diagram 2] FIG. 4 is a schematic diagram showing a modification of the first embodiment in which the positional relationship between the treated liquid recovery section and the water washing section in the absorber is changed. [Diagram 3] FIG. 4 is a schematic diagram showing a modification of the first embodiment in which the positional relationship between the treated liquid recovery section and the water washing section in the absorber is changed. [Figure 4] FIG. 4 is a diagram illustrating a modification of the first embodiment in which the separator is omitted. [Diagram 5] FIG. 10 is a diagram illustrating a schematic diagram of a modified example of the first embodiment, in which a first phase portion flowing through a first flow path section is introduced into a treatment liquid recovery section. [Figure 6] FIG. 13 is a diagram illustrating a schematic diagram of a modified example of the first embodiment in which a second processing liquid recovery unit is added. [Figure 7] FIG. 4 is a diagram illustrating a modification of the first embodiment in which a treated liquid recovery unit is provided in a regenerator. [Figure 8] FIG. 4 is a diagram illustrating a gas treatment device according to a second embodiment. [Figure 9] FIG. 13 is a diagram illustrating a gas treatment device according to a third embodiment. [Figure 10] FIG. 11 is a diagram illustrating a modification of the third embodiment, in which the water supply passage is connected to a water washing unit. [Figure 11] FIG. 13 is a diagram illustrating a modification of the third embodiment in which the moisture supply path is configured to be connected to a condenser in the discharge section. [Figure 12] FIG. 13 is a diagram illustrating a gas treatment device according to a fourth embodiment. [Figure 13] FIG. 13 is a diagram illustrating a gas treatment device according to a fifth embodiment. [Figure 14] FIG. 13 is a diagram illustrating a gas treatment device according to a sixth embodiment. [Figure 15] FIG. 13 is a diagram illustrating a gas treatment device according to a seventh embodiment. [Figure 16] FIG. 13 is a diagram showing a modified example in which the first flow path section and the second flow path section are provided in a portion downstream of the heat exchanger in the feed flow path. [Figure 17] 13 is a diagram showing a modified example in which a heat exchanger is provided in each of the first flow path portion and the second flow path portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0050] (First embodiment) As shown in FIG. 1, the gas treatment device 10 according to the first embodiment is a device that separates acidic compounds from a gas to be treated that contains the acidic compounds by using a treatment liquid having a property of reversibly absorbing and releasing the acidic compounds. In this embodiment, the target of separation is carbon dioxide (CO2), which is an acidic compound that generates an acid when dissolved in water, and is therefore effective as a measure against global warming. The acidic compound is not particularly limited as long as the aqueous solution is acidic, and may be, for example, hydrogen chloride, carbon dioxide, sulfur dioxide, carbon disulfide, etc. Examples of the gas to be treated that contains the acidic compounds include industrial exhaust gas, process gas generated during refining, and natural gas.

[0051] The treatment liquid is a treatment liquid in which the amine and the second component are mixed together before absorbing the acidic compound, and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound. The treatment liquid is, for example, an alkaline absorbent containing water, an amine, and an organic solvent as the second component, and may contain 30 wt% amine, 60 wt% organic solvent, and 10 wt% water.

[0052] As an amine, for example, 2-aminoethanol (MEA: solubility parameter = 14.3 (cal / cm 3 ) 1 / 2 ), 2-(2-aminoethoxy)ethanol (AEE: solubility parameter = 12.7 (cal / cm 3 ) 1 / 2), secondary amines such as 2-(methylamino)ethanol (MAE), 2-(ethylamino)ethanol (EAE), and 2-(butylamino)ethanol (BAE), and tertiary amines such as triethanolamine (TEA), N-methyldiethanolamine (MDEA), tetramethylethylenediamine (TEMED), pentamethyldiethylenetriamine (PMDETA), hexamethyltriethylenetetramine, and bis(2-dimethylaminoethyl)ether.

[0053] As an organic solvent, for example, 1-butanol (solubility parameter = 11.3 (cal / cm 3 ) 1 / 2 ), 1-pentanol (solubility parameter = 11.0 (cal / cm 3 ) 1 / 2 ), octanol, diethylene glycol diethyl ether (DEGDEE), diethylene glycol dimethyl ether (DEGDME), etc., and a mixture of two or more kinds may be used.

[0054] When the solubility parameters of the amine and the organic solvent are within a predetermined range, the treatment liquid forms a single liquid phase when it does not absorb the acidic compound, but when it absorbs the acidic compound, it undergoes phase separation into a first phase portion that has a high content of the acidic compound and mainly contains the amine, and a second phase portion that has a low content of the acidic compound and mainly contains the second component. Here, the solubility parameter is expressed by the following formula (1).

[0055]

number

[0056] ΔH is the molar latent heat of vaporization, R is the gas constant, T is the absolute temperature, and V is the molar volume.

[0057] [Table 1]

[0058] As shown in Table 1, in an absorbent containing water, an amine, and an organic solvent, the solubility parameter of the amine minus the solubility parameter of the organic solvent is 1.1 (cal / cm 3 ) 1 / 2 More than 4.2(cal / cm 3 ) 1 / 2 When the combination of amine and organic solvent is selected as shown below, a treatment liquid is obtained that is separated into two phases by absorption of the acidic compound: a first phase portion having a high content of the acidic compound and mainly containing the amine, and a second phase portion having a low content of the acidic compound and mainly containing the second component. Even in this case, before absorption of the acidic compound, the amine and the second component are mixed together to form a single liquid phase.

[0059] When the value of the difference in solubility parameters is less than the lower limit, the treatment liquid may not separate into two phases even if it absorbs an acidic compound. On the other hand, when the value of the difference in solubility parameters exceeds the upper limit, the treatment liquid may separate into two phases before absorbing an acidic compound, and in the step of contacting the treatment liquid with a gas to be treated containing an acidic compound, the contact state between the treatment liquid and the gas to be treated may become uneven, and the absorption efficiency may decrease. Note that "good" in Table 1 means that the treatment liquid was in a single liquid phase before absorbing carbon dioxide, and separated into two liquid phases due to the absorption of carbon dioxide. Also, "not miscible" in Table 1 means that the treatment liquid was in a two-liquid phase state before absorbing carbon dioxide, and did not form a single liquid phase. Also, "not separated" in Table 1 means that the treatment liquid was in a single liquid phase even after absorbing carbon dioxide.

[0060] As shown in Fig. 1, the gas treatment device 10 includes an absorber 12, a regenerator 14, a feed flow path 16, and a return flow path 18. The absorber 12 is a device for bringing a gas to be treated, such as a process gas, into contact with a treatment liquid, so that the treatment liquid absorbs acidic compounds in the gas to be treated. In this embodiment, carbon dioxide is separated as the acidic compound.

[0061] The feed flow path 16 is a flow path that extracts the treated liquid (rich liquid) that has absorbed carbon dioxide from the absorber 12 and introduces it into the regenerator 14. The regenerator 14 is a device for releasing carbon dioxide from the rich liquid by heating the rich liquid. The return flow path 18 is a flow path that extracts the treated liquid (lean liquid) after releasing carbon dioxide from the regenerator 14 and returns it to the absorber 12.

[0062] The absorber 12 is connected to an inlet passage 22 for supplying the gas to be treated to the absorber 12, a discharge passage 24 for discharging the gas after treatment (treated gas), a feed passage 16 for sending the treated liquid to the regenerator 14, and a return passage 18 for returning the treated liquid from the regenerator 14 to the absorber 12. The inlet passage 22 is connected to the lower part of the absorber 12, and the discharge passage 24 is connected to the upper part of the absorber 12. The feed passage 16 is connected to the lower part of the absorber 12. That is, the feed passage 16 is connected to the absorber 12 at a position where the treated liquid accumulated in the absorber 12 can be extracted. The return passage 18 is connected to the upper part of the absorber 12. That is, the return passage 18 is connected to the absorber 12 at a position where the treated liquid can flow down inside the absorber 12.

[0063] In the absorber 12, the gas to be treated introduced through the inlet line 22 comes into contact with the treatment liquid returned through the return line 18, and carbon dioxide in the gas to be treated is absorbed by the treatment liquid. In addition, treated gas, which is the gas from which carbon dioxide has been removed, is discharged from the absorber 12 through the discharge line 24. The absorption of carbon dioxide in the absorber 12 is an exothermic reaction. This reaction heat generated in the absorber 12 increases the temperatures of the gas to be treated, the treated gas, and the treatment liquid.

[0064] The treated liquid (rich liquid) that has absorbed carbon dioxide in the absorber 12 is discharged from the absorber 12 through the feed flow path 16. The rich liquid is phase-separated into a first phase portion that mainly contains amine and a second phase portion that mainly contains a second component (organic solvent). The feed flow path 16 is provided with a separator 26 for separating the treated liquid (rich liquid) in this phase-separated state into a treated liquid mainly containing the first phase portion and a treated liquid mainly containing the second phase portion. The separator 26 separates the first phase portion and the second phase portion using the specific gravity difference between them, and has a structure in which a vertical wall is provided in the space within the separator 26. The treated liquid introduced into the separator 26 is introduced into an inlet side space 26a, which is one space relative to the vertical wall. Of the treatment liquid stored in the inlet-side space 26a, the second phase portion, which has a low specific gravity, flows over the upper end of the standing wall and is introduced into the adjacent space 26b, so that the first phase portion is mainly stored in the inlet-side space 26a, and the second phase portion is mainly stored in the adjacent space 26b. In this way, in the separator 26, the treatment liquid is separated into a treatment liquid mainly containing the first phase portion and a treatment liquid mainly containing the second phase portion.

[0065] The feed flow path 16 includes a first flow path section 16a that discharges the treatment liquid (first phase portion) from the inlet side space 26a of the separator 26, and a second flow path section 16b that discharges the treatment liquid (second phase portion) from the adjacent space 26b of the separator 26.

[0066] The first flow path portion 16a and the second flow path portion 16b are provided with pumps 28 and 29, respectively.

[0067] Both the first flow path section 16a and the second flow path section 16b of the feed flow path 16 are connected to a heat exchanger 32. The heat exchanger 32 is for performing heat exchange between the treatment liquid (rich liquid) flowing through the feed flow path 16 and the treatment liquid (lean liquid) returned from the regenerator 14 to the absorber 12. It is noted that the heat exchanger 32 can be omitted.

[0068] The regenerator 14 is connected to a feed flow path 16 and a return flow path 18. The feed flow path 16 is connected to an upper part of the regenerator 14. The return flow path 18 is connected to a lower part of the regenerator 14. A pump 34 is provided in the return flow path 18.

[0069] The regenerator 14 stores the treatment liquid containing carbon dioxide introduced through the feed flow path 16. The regenerator 14 is provided with a heater 36 for heating the treatment liquid in the regenerator 14 to desorb carbon dioxide from the treatment liquid. When the treatment liquid is heated in the regenerator 14, not only is carbon dioxide desorbed, but water in the treatment liquid also evaporates. Note that desorption of carbon dioxide from the treatment liquid is an endothermic reaction.

[0070] A supply line 38 is connected to the regenerator 14 for supplying the gas containing carbon dioxide obtained in the regenerator 14 to a carbon dioxide demand destination. In the regenerator 14, a mixed gas of water vapor and carbon dioxide evaporated from the treatment liquid is generated, so a condenser 40 for cooling the mixed gas is provided in the supply line 38. When the mixed gas is cooled, the water vapor is condensed, and the water vapor can be separated. The condensed water obtained in the condenser 40 is usually returned to the regenerator 14. The condensed water may be returned to the absorber 12.

[0071] In the gas treatment device 10, a treatment liquid containing an amine is used, and this amine may become a mist or vapor and be entrained in the treated gas in the absorber 12. In this specification, a gas accompanied by the mist or vapor of the treatment liquid is also referred to as a treated liquid-accompanying gas. The gas treatment device 10 is provided with a treated liquid recovery section 42 for recovering the amine or the second component entrained in the treated liquid-accompanying gas.

[0072] The treated liquid mainly containing the second phase portion is introduced into the treated liquid recovery section 42 of this embodiment through an extraction line 44 connected to the second flow path section 16b of the feed flow path 16. In the treated liquid recovery section 42, the second phase portion extracted from the second flow path section 16b comes into contact with the treated liquid-accompanying gas in the absorber 12. For this reason, the treated liquid recovery section 42 of this embodiment mainly recovers the amine from the treated liquid entrained in the treated liquid-accompanying gas.

[0073] The treated liquid recovery section 42 is disposed in the absorber 12 above the connection portion of the reflux line 18. Therefore, the treated liquid in a mist or vapor state that flows in through the reflux line 18 and is entrained by the gas, or the treated liquid in a mist or vapor state that is generated from the treated liquid in the absorber 12 and is entrained by the gas, comes into contact with the introduced liquid second phase portion. As a result, the amine in a mist or vapor state is taken up in the second phase portion.

[0074] The absorber 12 is also provided with a water washing section 46 that brings the treated liquid entrained gas and wash water into contact with each other to recover the treated liquid entrained in the treated liquid entrained gas that could not be recovered in the treated liquid recovery section 42. Since the treated liquid entrained gas entrains not only amine but also an organic solvent as a second component, the water washing section 46 recovers the organic solvent and amine in the mist or vapor state that have passed through the treated liquid recovery section 42 by contacting the organic solvent and amine with wash water. It is possible to omit the water washing section 46.

[0075] The water washing section 46 and the treatment liquid recovery section 42 are positioned so that the treatment liquid entrained gas comes into contact with the cleaning water after coming into contact with the second phase portion in the treatment liquid recovery section 42. For this reason, in Fig. 1, the water washing section 46 is disposed above the treatment liquid recovery section 42. By positioning them in this way, even if the water washing section 46 is provided, the amount of cleaning water supplied can be reduced, and therefore dilution of the treatment liquid can be prevented.

[0076] In addition, the water washing section 46 does not need to be disposed above the treated liquid recovery section 42, so long as the treated liquid-accompanying gas that has passed through the treated liquid recovery section 42 comes into contact with the wash water. For example, as shown in FIG. 2, in the absorber 12, the treated liquid recovery section 42 and the water washing section 46 may be disposed so as to be aligned in the horizontal direction, and a flow path 12a may be formed through which the treated liquid-accompanying gas passes through the treated liquid recovery section 42 from bottom to top and is then introduced into the lower part of the water washing section 46. In addition, as shown in FIG. 3, in the absorber 12, the treated liquid-accompanying gas may be configured to flow horizontally through the treated liquid recovery section 42 and the water washing section 46, and the absorber 12 may be provided with a meandering flow path section 12b between the treated liquid recovery section 42 and the water washing section 46 so that the first phase portion or the second phase portion introduced into the treated liquid recovery section 42 does not flow into the water washing section 46. Instead of providing the serpentine flow path section 12b, the absorber 12 may be divided into a vessel portion having the treated liquid recovery section 42 and a vessel portion having the water washing section 46.

[0077] Here, a description will be given of a gas processing method using the gas processing device 10 according to the first embodiment. The gas processing method includes an absorption step and a regeneration step.

[0078] The absorption step is a step in which the gas to be treated is brought into contact with the treatment liquid in the absorber 12. The gas to be treated, such as a process gas containing at least carbon dioxide, is supplied to the absorber 12 through an inlet 22. The treatment liquid is also introduced into the absorber 12 through a return path 18. The treatment liquid comes into contact with the carbon dioxide contained in the gas to be treated and absorbs the carbon dioxide. The treatment liquid (rich liquid) that has absorbed the carbon dioxide undergoes phase separation into a first phase portion having a high carbon dioxide content and a second phase portion having a low carbon dioxide content.

[0079] The treated liquid in the absorber 12 is introduced into the separator 26 through the feed flow path 16. From the separator 26, a first phase portion mainly containing amine is discharged through the first flow path section 16a, and a second phase portion mainly containing a second component (organic solvent) is discharged through the second flow path section 16b. The first and second phase portions join together and are heated in the heat exchanger 32 by heat exchange with the treated liquid (lean liquid) flowing through the return flow path 18. The treated liquid that has passed through the heat exchanger 32 is introduced into the regenerator 14.

[0080] The treatment liquid introduced into the regenerator 14 is heated by a heater 36, whereby carbon dioxide is separated from the treatment liquid (regeneration step). The carbon dioxide separated from the treatment liquid is sent to a demand destination through a supply line 38. In the regenerator 14, water vapor obtained from the treatment liquid is condensed by a condenser 40 in the supply line 38, and is usually returned to the regenerator 14. The water vapor may be returned to the absorber 12.

[0081] The treated liquid (lean liquid) stored in the regenerator 14 flows through the return path 18 and returns to the absorber 12. The treated liquid in the return path 18 heats the treated liquid flowing through the feed path 16 in the heat exchanger 32.

[0082] A part of the second phase portion flowing through the second flow passage portion 16b of the feed flow passage 16 is sent to the treated liquid recovery section 42 in the absorber 12 through the withdrawal passage 44. In the treated liquid recovery section 42, the second phase portion introduced through the withdrawal passage 44 comes into contact with a treated liquid-accompanying gas generated from the treated liquid in the absorber 12. This treated liquid-accompanying gas is accompanied by mist- or vapor-like treated liquid. As a result, the amine in the mist- or vapor-like form is taken into the liquid second phase portion, and the amine is recovered from the treated liquid-accompanying gas in the absorber 12, and this amine can be merged with the liquid treated liquid.

[0083] In the treated liquid recovery section 42, a part of the introduced second phase fraction may be entrained in the treated liquid entrained gas, and this treated liquid entrained gas comes into contact with the wash water in the water washing section 46. Therefore, the entrained second phase fraction is taken up in the wash water.

[0084] As described above, in the gas treatment device 10 of this embodiment, the second phase portion for recovery flowing out from the absorber 12 comes into contact with the treated liquid-accompanying gas in the treated liquid recovery section 42. At this time, the second phase portion mainly containing the second component is brought into contact with the treated liquid-accompanying gas, so that the second component in the second phase portion is likely to mix with the amine entrained in the treated liquid-accompanying gas. Therefore, the amine entrained in the treated liquid-accompanying gas can be recovered. In addition, although washing with washing water is used in combination, the amount of washing water can be reduced, so that the treated liquid is prevented from being diluted. Therefore, the performance of separating and recovering acidic compounds via the treated liquid can be prevented from being reduced.

[0085] In this embodiment, a separator 26 is provided, and the second phase portion of the treated liquid separated in the separator 26 is introduced into the treated liquid recovery section 42. Therefore, the amine entrained in the treated liquid-accompanying gas can be effectively recovered.

[0086] In this embodiment, the second phase portion is used for contact with the treatment liquid-accompanying gas in the treatment liquid recovery section 42, and a part of this second phase portion is entrained in the treatment liquid-accompanying gas. The treatment liquid-accompanying gas then comes into contact with the cleaning water in the water washing section 46, and the second phase portion entrained in the treatment liquid-accompanying gas is recovered. Therefore, in the treatment liquid recovery section 42, the treatment liquid entrained in the treatment liquid-accompanying gas can be recovered, and the second phase portion used in the treatment liquid recovery section 42 and entrained in the treatment liquid-accompanying gas can also be recovered.

[0087] In this embodiment, the separator 26 is provided, but the separator 26 can be omitted. For example, as shown in FIG. 4, the feed flow path 16 may include a first flow path portion 16a and a second flow path portion 16b, and the first flow path portion 16a and the second flow path portion 16b may be connected to the absorber 12, respectively. In this case, the first flow path portion 16a is connected to the lower end of the absorber 12, and the second flow path portion 16b is connected to the absorber 12 at a position higher than the connection portion of the first flow path portion 16a. That is, the treatment liquid accumulated in the absorber 12 is phase-separated into a first phase portion and a second phase portion. In addition, the first phase portion mainly containing amine is heavier than the second phase portion mainly containing the second component (organic solvent). Therefore, the composition ratio of the first phase portion and the second phase portion of the treatment liquid accumulated in the absorber 12 differs depending on the vertical position. Therefore, by making the position at which the treatment liquid is extracted by the first flow path section 16a and the position at which the treatment liquid is extracted by the second flow path section 16b different in the height direction, the treatment liquid can be separated into a first phase portion and a second phase portion.

[0088] In this embodiment, the second phase portion flowing through the second flow path section 16b is introduced into the treatment liquid recovery section 42, but the present invention is not limited to this configuration. As shown in FIG. 5, the first phase portion flowing through the first flow path section 16a may be introduced into the treatment liquid recovery section 42. In this case, the discharge path 44 is connected to the first flow path section 16a instead of the second flow path section 16b. The first phase portion introduced into the treatment liquid recovery section 42 through the discharge path 44 comes into contact with the mist-like or vapor-like treatment liquid entrained in the treatment liquid-accompanying gas. At this time, the first phase portion takes in the second component in the mist-like or vapor-like treatment liquid, and therefore the second component can be recovered from the treatment liquid-accompanying gas.

[0089] 6, in addition to the withdrawal path 44 that introduces the first phase portion flowing through the first flow path section 16a into the treated liquid recovery section 42, a second withdrawal path 45 that introduces the second phase portion flowing through the second flow path section 16b into a second treated liquid recovery section 43 may be provided. The second treated liquid recovery section 43 brings the second phase portion mainly containing the second component (organic solvent) into contact with the treated liquid-accompanying gas in the absorber 12, and mainly recovers the second component.

[0090] 7, the treated liquid recovery section 42 may be provided in the regenerator 14. In this case, the treated liquid recovery section 42 is disposed at a position above the connection section of the feed flow path 16 in the regenerator 14. In FIG. 7, the second phase portion is supplied to the treated liquid recovery section 42 through the withdrawal path 44 connected to the second flow path section 16b, but instead of / in addition to this, the first phase portion may be supplied to the treated liquid recovery section 42 through the withdrawal path 44 connected to the first flow path section 16a.

[0091] Second embodiment 8, in the second embodiment, a gas for promoting separation of acidic compounds (hereinafter, referred to as a separation promoting gas) is introduced into a regenerator 14. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0092] The gas treatment device 10 according to the second embodiment is provided with a separation promotion gas supplying section 50 for supplying a separation promotion gas to the regenerator 14. The separation promotion gas is a gas that is almost insoluble in the treatment liquid. In other words, the separation promotion gas is almost not absorbed by the treatment liquid. In addition, the separation promotion gas does not cause a chemical reaction with the treatment liquid. Examples of the separation promotion gas include hydrocarbon gases such as hydrogen gas, oxygen gas, and methane gas, but hydrogen gas is used in this embodiment. Examples of the separation promotion gas include water vapor, or a mixed gas of water vapor and a gas that is almost insoluble in the treatment liquid. By supplying a gas that is almost insoluble in the treatment liquid, water vapor, or a mixed gas of water vapor and a gas that is almost insoluble in the treatment liquid to the regenerator 14, the gas partial pressure of the acidic compounds in the regenerator 14 can be reduced, and separation of the acidic compounds from the treatment liquid in the regenerator 14 can be promoted.

[0093] Here, "almost insoluble" in the treatment liquid may mean that the solubility in the treatment liquid is equal to or less than a predetermined value. The separation promoting gas may be, for example, a gas that follows Henry's law and has a solubility of 1 mol or less in 100 g of treatment liquid under conditions of 0°C and 100 kPa. The solubility of oxygen in water is 1.3×10 -4mol / 100g, the solubility of methane in water is 8 x 10 -4 mol / 100g, the solubility of hydrogen in water is 9.5×10 -5 mol / 100g. In contrast, the solubility of ammonia in water is 6 mol / 100g, so ammonia does not qualify as a separation-promoting gas.

[0094] The gas processing device 10 is provided with a moisture removal unit 52 that removes moisture from the hydrogen gas. That is, when hydrogen gas, which is a separation promoting gas, is obtained by water electrolysis, moisture close to saturation may be retained in the hydrogen gas. For this reason, the moisture removal unit 52 is provided to prevent the moisture retained in the hydrogen gas from being introduced into the regenerator 14 and diluting the treatment liquid.

[0095] The moisture removal unit 52 includes a cooler 52a that separates moisture from the hydrogen gas by cooling the hydrogen gas, and a gas-liquid separator 52b that stores the separated water obtained by the cooler 52a. The separated water stored in the gas-liquid separator 52b is discharged outside the system.

[0096] The moisture removing unit 52 is not limited to one that separates moisture by cooling the hydrogen gas, but may be configured to remove moisture by, for example, adsorbing the moisture onto an adsorbent.

[0097] Furthermore, when the separation promotion gas does not contain moisture, such as when a dry separation promotion gas is supplied, the moisture removal section 52 can be omitted.

[0098] Since the separation promoting gas is supplied to the regenerator 14, the amount of gas in the regenerator 14 increases compared to the first embodiment. In addition, the gas in the regenerator 14 (gas containing carbon dioxide separated from the treatment liquid) may be accompanied by mist-like or vapor-like treatment liquid. This gas accompanying the treatment liquid is called a treatment liquid-accompanying gas. In this embodiment, a treatment liquid recovery section 42 is provided in the regenerator 14 in order to recover the mist-like or vapor-like treatment liquid entrained by the treatment liquid-accompanying gas in the regenerator 14.

[0099] The treatment liquid recovery section 42 is disposed at a position above the connection part of the feed flow path 16 in the regenerator 14. That is, in order to prevent the treatment liquid introduced from the feed flow path 16 from passing through the treatment liquid recovery section 42, the treatment liquid recovery section 42 is disposed above the connection part of the feed flow path 16.

[0100] As shown in FIG. 8, the second phase portion may be introduced into the treatment liquid recovery section 42 from the second flow path section 16b, or, although not shown, the first phase portion may be introduced into the treatment liquid recovery section 42 from the first flow path section 16a.

[0101] In this embodiment, the regeneration temperature can be lowered by supplying the separation promoting gas to the regenerator 14. Therefore, it becomes possible to use lower temperature (low quality) heat.

[0102] In this embodiment, the separation promoting gas is supplied to the regenerator 14 by the separation promoting gas supply unit 50, so the amount of gas in the regenerator 14 is increased. Accordingly, the amount of treated liquid entrained in the treated liquid-accompanying gas also increases. However, since the second phase portion for recovery flowing out from the absorber 12 is introduced into the regenerator 14, even if the amount of treated liquid entrained in the treated liquid-accompanying gas in the regenerator 14 increases, the entrained treated liquid can be effectively recovered.

[0103] In this embodiment, moisture is removed from the separation promotion gas, which is hydrogen gas containing moisture, in the moisture remover 52. This not only makes it possible to lower the regeneration temperature, but also makes it possible to prevent the treatment liquid from being diluted by the separation promotion gas.

[0104] In this embodiment, the discharge passage 44 is connected to the second flow passage 16b through which the second phase portion mainly flows, but instead, the discharge passage 44 may be connected to the first flow passage 16a through which the first phase portion mainly flows. In addition to the discharge passage 44 that introduces the first phase portion flowing through the first flow passage 16a to the treated liquid recovery section 42, a second discharge passage 45 that introduces the second phase portion flowing through the second flow passage 16b to the second treated liquid recovery section 43 as shown in FIG. 6 may be provided. In addition, the treated liquid recovery section 42 is provided in the regenerator 14, but instead of this / along with this, the treated liquid recovery section 42 may be provided in the absorber 12 as in FIG. 1, FIG. 5, and FIG. 6. In addition, the separator 26 may be omitted as in FIG. 4. Although the description of other configurations, actions, and effects is omitted, the description of the first embodiment can be applied to the second embodiment.

[0105] Third embodiment 9, in the third embodiment, the moisture obtained in the moisture remover 52 is used to wash the gas entrained in the treatment liquid. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0106] The gas processing device 10 according to the third embodiment is provided with a moisture supply path 54 that supplies the moisture obtained in the moisture removal section 52 to the condenser 40. One end of the moisture supply path 54 is connected to the gas-liquid separator 52b, and the other end is connected to a portion of the supply path 38 that is upstream of the condenser 40. The other end may be connected to the condenser 40.

[0107] The separated water accumulated in the gas-liquid separator 52b is sent to the supply line 38 through the moisture supply line 54. Therefore, even if the gas entrained with the treated liquid in the regenerator 14 flows into the supply line 38, the treated liquid entrained in the gas entrained with the treated liquid is taken in by the separated water and is returned to the regenerator 14 via the condenser 40.

[0108] In this embodiment, the moisture obtained in the moisture removal section 52 is supplied to the condenser 40 provided in the supply line 38 through the moisture supply line 54. Then, in the condenser 40, the treated liquid entrained in the treated liquid-accompanying gas flowing out from the regenerator 14 is recovered. That is, the moisture obtained in the moisture removal section 52 is used to recover the treated liquid entrained in the treated liquid-accompanying gas. Therefore, the moisture separated in the moisture removal section 52 can be effectively utilized.

[0109] In this embodiment, the moisture supply path 54 is connected to the supply path 38, but is not limited to this. As shown in Fig. 10, the moisture supply path 54 may supply moisture to at least one of the water washing section 46 in the absorber 12 and the water washing section 46 in the regenerator 14. Also, as shown in Fig. 11, the moisture supply path 54 may supply moisture to a condenser 56 provided in the discharge path 24. In this case, the water washing section 46 may be provided in the absorber 12 or may be omitted.

[0110] In this embodiment, the discharge passage 44 is connected to the second flow passage 16b through which the second phase portion mainly flows, but instead, the discharge passage 44 may be connected to the first flow passage 16a through which the first phase portion mainly flows. In addition to the discharge passage 44 that introduces the first phase portion flowing through the first flow passage 16a to the treated liquid recovery section 42, a second discharge passage 45 that introduces the second phase portion flowing through the second flow passage 16b to the second treated liquid recovery section 43 may be provided. In addition, the treated liquid recovery section 42 is provided in the regenerator 14, but instead of this / along with this, the treated liquid recovery section 42 may be provided in the absorber 12 as in Figures 1, 5, and 6. Also, as in Figure 4, the separator 26 may be omitted. Other configurations, actions, and effects will not be described, but the descriptions of the first and second embodiments can be applied to the third embodiment.

[0111] (Fourth embodiment) As shown in FIG. 12, in the fourth embodiment, a separation promotion gas supplying section 50 and a moisture removing section 52 are provided, but a treatment liquid recovery section 42 is not provided. That is, in the fourth embodiment, the separation promotion gas supplying section 50 supplies a separation promotion gas consisting of a moisture-containing gas or water vapor to the regenerator 14, so there is a possibility that moisture may be brought into the regenerator 14 by the separation promotion gas. Therefore, the moisture removing section 52 can suppress this and suppress the treatment liquid from being diluted. For this reason, the treatment liquid recovery section 42 that recovers the treatment liquid entrained in the treatment liquid-accompanying gas by the first phase part or the second phase part of the treatment liquid is omitted. Here, the same reference numerals are given to the same components as those in the first and second embodiments, and detailed explanations thereof will be omitted.

[0112] In the fourth embodiment, the regeneration temperature can be lowered by supplying the separation promotion gas to the regenerator 14. Therefore, it becomes possible to use lower temperature (low quality) heat. Moreover, in the moisture removal section 52, moisture is removed from the separation promotion gas, which is a gas containing moisture or a gas composed of water vapor, and then the separation promotion gas is supplied to the regenerator 14. Therefore, it is possible to prevent the treatment liquid from being diluted by the separation promotion gas. Therefore, it is possible to prevent a decrease in the separation and recovery performance of acidic compounds via the treatment liquid.

[0113] 12, the separator 26 is provided in the feed channel 16, and the feed channel 16 has the first channel portion 16a and the second channel portion 16b, but this is not limited to the above. The separator 26 may be omitted, and the feed channel 16 may be configured as a single channel without having the first channel portion 16a and the second channel portion 16b. Other configurations, actions, and effects will not be described here, but the descriptions of the first and second embodiments can be applied to the fourth embodiment.

[0114] Fifth embodiment 13 shows the fifth embodiment. Note that the same components as those in the first to fourth embodiments are given the same reference numerals, and detailed description thereof will be omitted.

[0115] In the fifth embodiment, the concentration of the gas to be treated is measured, and when the amount of the mist or vapor of the treatment liquid entrained in the treatment liquid entraining gas increases or is expected to increase, the treatment liquid is recovered from the treatment liquid entraining gas, and the treatment liquid is not recovered otherwise. This prevents the energy required for the treatment liquid recovery from increasing too much.

[0116] Specifically, the gas treatment device 10 is provided with at least one of a measuring device 58 arranged in the inlet path 22 and capable of measuring the concentration of sulfur contained in the gas to be treated or the flow rate of the gas to be treated, a measuring device 59 arranged in the exhaust path 24 and capable of measuring the concentration of an amine or a second component contained in the treated gas, a measuring device 60 arranged in the supply path 38 and capable of measuring the concentration of an amine or a second component contained in the gas containing carbon dioxide, and a measuring device 61 arranged in the return path 18 and capable of measuring the concentration of a deteriorated component contained in the treatment liquid.

[0117] Signals indicating the measurement results by the measuring instruments 58 to 61 are sent to the control unit 63. The control unit 63 is configured to adjust at least one of the valve 65 and the cooler 52a provided in the extraction line 44 based on the measurement results indicated by the received signal. For example, when the measurement result by the measuring instrument 58 arranged in the introduction line 22 indicates that the treated gas contains sulfur content equal to or greater than a threshold value, the control unit 63 may control to open the valve 65 or control to operate the cooler 52a. This is because there is a possibility that the generation of amine mist is promoted when the sulfur content is high. In addition, when the measurement result by the measuring instrument 58 arranged in the introduction line 22 indicates that the treated gas flow rate is equal to or greater than a threshold value, the control unit 63 may control to open the valve 65 or control to operate the cooler 52a. This is because it is predicted that the discharge amount of amine or the second component may increase if the flow rate of the treated gas increases. Furthermore, when the measurement result by the measuring device 59 disposed in the discharge path 24 indicates that the treated gas contains an amine or the second component at a concentration equal to or higher than the threshold value, the control unit 63 may control to open the valve 65 or to operate the cooler 52a. This is because this would mean that the amount of discharge of the amine or the second component is actually increasing. Furthermore, when the measurement result by the measuring device 61 disposed in the return path 18 indicates that the treatment liquid contains a deterioration component that causes the amine to bubble at a concentration equal to or higher than the threshold value, the control unit 63 may control to open the valve 65 or to operate the cooler 52a. This is because when the deterioration component increases due to aging of the treatment liquid, the amine in the treatment liquid is more likely to be lost.

[0118] In the fifth embodiment, when the amount of evaporation or mist of the treatment liquid is large or is expected to be large, the vapor or mist of the treatment liquid can be appropriately recovered. On the other hand, when the amount of evaporation or mist of the treatment liquid is small or is expected to be small, the energy required for recovery of the treatment liquid can be reduced.

[0119] Furthermore, when the measurement result by at least one of the measuring device 59 arranged in the discharge path 24 and the measuring device 60 arranged in the supply path 38 indicates that the concentration of the amine or the second component contained in the gas is higher than the threshold value, the control unit 63 may perform at least one of the control to increase the opening degree of the valve 65 and the control to increase the capacity of the cooler 52a. On the other hand, when the measurement result by at least one of the measuring device 59 arranged in the discharge path 24 and the measuring device 60 arranged in the supply path 38 indicates that the concentration of the amine or the second component contained in the gas is lower than the threshold value, the control unit 63 may perform at least one of the control to decrease the opening degree of the valve 65 and the control to decrease the capacity of the cooler 52a.

[0120] In this case, when the amount of evaporation or mist of the treatment liquid is large, the vapor or mist of the treatment liquid can be appropriately collected, whereas when the amount of evaporation or mist of the treatment liquid is small, the amount of water removed can be reduced, thereby reducing the energy required for removing the water.

[0121] In the embodiment shown in FIG. 13, the water washing unit 46 is provided, but the water washing unit 46 can be omitted. That is, if the second component (organic solvent) is not easily volatilized, the water washing unit 46 can be omitted. Even in this case, the control unit 63 is configured to adjust at least one of the valve 65 and the cooler 52a based on the measurement result indicated by the received signal. Also, the treated liquid recovery unit 42 may be provided in the absorber 12 instead of / in addition to the regenerator 14. Although a description of the other configurations, operations, and effects will be omitted, the description of the first to fourth embodiments can be applied to the fifth embodiment.

[0122] Sixth embodiment 14 shows the sixth embodiment. Note that the same components as those in the first to fifth embodiments are given the same reference numerals, and detailed description thereof will be omitted.

[0123] In the sixth embodiment, the control unit 63 not only adjusts at least one of the valve 65 and the cooler 52a provided in the extraction path 44, but also adjusts a valve 66 provided in a washing water path 67 for supplying washing water to the water washing unit 46. The valve 65 in the extraction path 44 may be omitted. The washing water path 67 may be formed by the moisture supply path 54.

[0124] When the measurement result by at least one of the measuring device 59 arranged in the discharge path 24 and the measuring device 60 arranged in the supply path 38 indicates that the concentration of the amine or the second component contained in the gas is higher than the threshold value, the control unit 63 performs at least one of the following controls: control to increase the opening of the valve 66 provided in the cleaning water path 67 and control to increase the capacity of the cooler 52a. On the other hand, when the measurement result by at least one of the measuring device 59 arranged in the discharge path 24 and the measuring device 60 arranged in the supply path 38 indicates that the concentration of the amine or the second component contained in the gas is lower than the threshold value, the control unit 63 performs at least one of the following controls: control to decrease the opening of the valve 66 provided in the cleaning water path 67 and control to decrease the capacity of the cooler 52a.

[0125] In the sixth embodiment, when the amount of evaporation or mist of the treatment liquid is large, the vapor or mist of the treatment liquid can be appropriately collected.

[0126] It should be noted that the explanations of the other configurations, operations and effects will be omitted, but the explanations of the first to fifth embodiments can be applied to the sixth embodiment.

[0127] Seventh embodiment 15 shows the seventh embodiment. Note that the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0128] In the seventh embodiment, the control unit 63 is configured to adjust at least one of the valve 65 provided in the extraction line 44, the valve 66 provided in the washing water line 67, and the cooler 52a, based on the measurement result indicated by the received signal. That is, in the fifth embodiment, the flow rate of water supplied to the water washing unit 46 is not adjusted, whereas in the seventh embodiment, the amount of water supplied to the water washing unit 46 can also be adjusted. This makes it possible to more appropriately adjust the amount of water supplied to the absorber 12 or the regenerator 14. Note that, although the measuring device 61 arranged in the return line 18 is omitted in FIG. 15, the measuring device 61 may be provided in the return line 18.

[0129] It should be noted that the explanations of the other configurations, operations and effects will be omitted, but the explanations of the first to sixth embodiments can be applied to the seventh embodiment.

[0130] (Other embodiments) It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The present invention is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the present invention. For example, in the first to seventh embodiments, the feed flow path 16 includes the first flow path section 16a and the second flow path section 16b, which are disposed at a position upstream of the heat exchanger 32, and the extraction path 44, but is not limited thereto. As shown in FIG. 16, the first flow path section 16a and the second flow path section 16b may be provided at a position downstream of the heat exchanger 32 in the feed flow path 16. In this case, the first phase portion or the second phase portion supplied to the treatment liquid recovery section 42 becomes a liquid heated by the heat exchanger 32. For this reason, as shown in FIG. 1 and the like, in order to further enhance the recovery effect of the treatment liquid, it is preferable to supply the first phase portion or the second phase portion before being heated by the heat exchanger 32 to the treatment liquid recovery section 42.

[0131] Also, as shown in FIG. 17, a heat exchanger 32 may be provided in each of the first flow path section 16a and the second flow path section 16b. That is, a heat exchanger 32a that exchanges heat between a first phase portion of the rich liquid and the lean liquid, and a heat exchanger 32b that exchanges heat between a second phase portion of the rich liquid and the lean liquid may be provided. Note that, although FIG. 17 shows a configuration in which the heat exchanger 32a and the heat exchanger 32b are connected in parallel, the heat exchanger 32a and the heat exchanger 32b may be connected in series. However, the heat recovery efficiency is higher when the heat exchanger 32a and the heat exchanger 32b are connected in parallel. [Explanation of symbols]

[0132] 10: Gas treatment equipment 12: Absorber 14:Regenerator 24:Exhaust channel 26:Separator 38: Supply route 40: Condenser 42: Processing liquid recovery section 43: Second processing liquid recovery section 46: Washing section 50: Separation promotion gas supply section 52: Moisture removal section 54: Moisture supply path 56: Condenser 63: Control section

Claims

1. an absorber for bringing into contact with a gas to be treated, which contains an acidic compound that generates an acid when dissolved in water, and a treatment liquid, which is in a state in which an amine and a second component are mixed before absorbing the acidic compound, and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, so that the acidic compound contained in the gas to be treated is absorbed into the treatment liquid; a regenerator for heating the treatment liquid having absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; a treated liquid recovery section that brings at least one of the first phase portion and the second phase portion flowing out from the absorber into contact with a treated liquid-accompanying gas, which is a gas in the absorber after the acidic compounds from the gas to be treated are absorbed into the treated liquid or a gas in the regenerator containing the acidic compounds, to recover the treated liquid entrained in the treated liquid-accompanying gas; A gas treatment device comprising:

2. 2. The gas treatment device according to claim 1, A gas treatment device comprising: a separator that separates the treatment liquid having absorbed the acidic compound into a treatment liquid mainly containing the first phase portion and a treatment liquid mainly containing the second phase portion.

3. 2. The gas treatment device according to claim 1, a water washing section for contacting the treatment liquid entrained gas with washing water to recover the treatment liquid entrained in the treatment liquid entrained gas, The treated liquid recovery section is disposed at a position where the absorption liquid that has been phase-separated into the first phase portion and the second phase portion comes into contact with the treated liquid-accompanying gas before coming into contact with the wash water in the water washing section.

4. 3. The gas treatment device according to claim 1, a separation promoting gas supply unit that supplies a separation promoting gas consisting of a gas or water vapor that is almost insoluble and inactive in the treatment liquid to the regenerator; The gas treatment device, wherein the treated liquid recovery section is configured to contact at least one of the first phase portion and the second phase portion flowing out from the absorber with a pretreated liquid-accompanied gas.

5. 5. The gas treatment device according to claim 4, The gas treatment device, wherein the treated liquid recovery section is configured to contact at least one of the first phase portion and the second phase portion flowing out from the absorber with a gas containing the acidic compound in the regenerator.

6. 5. The gas treatment device according to claim 4, The separation-promoting gas is a gas containing moisture or a gas consisting of water vapor, A gas treatment device comprising: a moisture removal unit that separates moisture contained in the separation-promoting gas from the separation-promoting gas supplied to the regenerator.

7. 5. The gas treatment device according to claim 4, The separation-promoting gas is a gas containing moisture or a gas consisting of water vapor, a moisture removal unit that separates moisture contained in the separation promotion gas from the separation promotion gas supplied to the regenerator; The moisture obtained in the moisture removing section is A water washing section of the absorber; A water washing section of the regenerator; A condenser provided in a supply path for supplying the acidic compound obtained in the regenerator to a destination; and a condenser provided in a discharge path for discharging the treated gas from the absorber; A moisture supply path that supplies moisture to at least one of the above. The gas treatment device comprises:

8. an absorber for bringing a gas to be treated, which contains an acidic compound that generates an acid when dissolved in water, into contact with a treatment liquid, which is in a state in which an amine and a second component are mixed before absorbing the acidic compound and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, so as to absorb the acidic compound in the gas to be treated into the treatment liquid; a regenerator for heating the treatment liquid having absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; a separation promoting gas supply unit that supplies a separation promoting gas, which is a gas that is almost insoluble and inactive in the treatment liquid and contains moisture or water vapor, to the regenerator; a moisture removing section that removes moisture contained in the separation promoting gas from the separation promoting gas supplied to the regenerator.

9. In an absorber, a gas to be treated containing an acidic compound that generates an acid when dissolved in water is brought into contact with a treatment liquid which is in a state in which an amine and a second component are mixed before absorbing the acidic compound and which undergoes phase separation into a first phase portion mainly containing the amine and a second phase portion mainly containing the second component upon absorption of the acidic compound, thereby allowing the acidic compound contained in the gas to be treated to be absorbed into the treatment liquid; In a regenerator, the treatment liquid having absorbed the acidic compounds is heated to separate the acidic compounds from the treatment liquid; allowing the first phase portion and the second phase portion to flow from the absorber; A gas treatment method comprising contacting at least one of the first phase portion and the second phase portion flowing out of the absorber with a treated liquid-accompanying gas, which is the gas in the absorber after the acidic compounds from the gas to be treated are absorbed by the treated liquid or a gas in the regenerator containing the acidic compounds, and recovering the treated liquid entrained in the treated liquid-accompanying gas.

10. 10. The gas processing method according to claim 9, a separator for separating the treated liquid having absorbed the acidic compound into a treated liquid mainly containing the first phase portion and a treated liquid mainly containing the second phase portion.

11. 11. The gas processing method according to claim 9, The absorption liquid separated into the first phase portion and the second phase portion is contacted with the treated liquid-carrying gas; Thereafter, the gas in the absorber or the gas in the regenerator is contacted with wash water to recover a treatment liquid entrained in the gas to be treated.

12. 11. The gas processing method according to claim 9, A separation promoting gas consisting of a gas or water vapor having almost no solubility or reactivity in the treatment liquid is supplied to the regenerator; a first phase portion and / or a second phase portion discharged from the absorber is contacted with the treated liquid-carrying gas.

13. 13. The gas processing method according to claim 12, A gas treatment method comprising contacting at least one of the first phase portion and the second phase portion flowing out from the absorber with a gas containing the acidic compound in the regenerator.

14. 13. The gas processing method according to claim 12, The separation-promoting gas is a gas containing moisture or a gas consisting of water vapor, Separating moisture contained in the separation-promoting gas from the separation-promoting gas supplied to the regenerator; the separated moisture is brought into contact with the treated liquid-accompanying gas, and the treated liquid entrained in the treated liquid-accompanying gas is recovered.

15. 13. The gas processing method according to claim 12, Separating moisture contained in the separation-promoting gas from the separation-promoting gas supplied to the regenerator; the separated moisture is supplied to at least one of a water washing section of the absorber, a water washing section of the regenerator, a condenser provided in a supply path for supplying the acidic compounds obtained in the regenerator to a destination, and a condenser provided in a discharge path for discharging the treated gas after treatment from the absorber.

16. 15. The gas processing method according to claim 14, Measure at least one of the following: a concentration of sulfur contained in the gas to be treated introduced into the absorber; a flow rate of the gas to be treated introduced into the absorber; a concentration of an amine or a second component contained in the treated gas discharged from the absorber; a concentration of an amine or a second component contained in the gas containing an acidic compound discharged from the regenerator; and a concentration of a deteriorated component contained in the treatment liquid introduced into the absorber; and adjusting, based on the results of the measurement, at least one of the flow rate of water separated from the separation-promoting gas and brought into contact with the treatment liquid-accompanying gas, the flow rate of the first phase portion or the second phase portion brought into contact with the treatment liquid-accompanying gas, and the flow rate of wash water supplied to a water washing section provided in at least one of the absorber and the regenerator.

17. 17. The gas processing method according to claim 16, when a measurement result of at least one of the concentration of the amine or the second component contained in the treated gas discharged from the absorber and the concentration of the amine or the second component contained in the gas containing acidic compounds discharged from the regenerator becomes higher than a threshold value, at least one of the flow rate of the water separated from the separation promoting gas and brought into contact with the treated liquid-accompanying gas and the flow rate of the wash water supplied to the water washing section is increased, a flow rate of the water separated from the separation-promoting gas and brought into contact with the treatment liquid-carrying gas and a flow rate of the wash water supplied to the water washing section are reduced when a measurement result of at least one of a concentration of the amine or the second component contained in the treated gas discharged from the absorber and a concentration of the amine or the second component contained in the gas containing acidic compounds discharged from the regenerator becomes lower than a threshold value.

18. 13. The gas processing method according to claim 12, Measure at least one of the following: a concentration of sulfur contained in the gas to be treated introduced into the absorber; a flow rate of the gas to be treated introduced into the absorber; a concentration of an amine or a second component contained in the treated gas discharged from the absorber; a concentration of an amine or a second component contained in the gas containing an acidic compound discharged from the regenerator; and a concentration of a deteriorated component contained in the treatment liquid introduced into the absorber; A gas processing method, comprising adjusting at least one of the flow rate of moisture separated from the separation-promoting gas and brought into contact with the treatment liquid-carrying gas and the flow rate of the first phase portion or the second phase portion brought into contact with the treatment liquid-carrying gas based on the results of the measurement.

19. In an absorber, a gas to be treated containing an acidic compound which generates an acid when dissolved in water is brought into contact with a treatment liquid which undergoes phase separation into a first phase portion mainly containing an amine phase and a second phase portion mainly containing a component phase other than amines due to absorption of the acidic compound, thereby allowing the acidic compound contained in the gas to be treated to be absorbed into the treatment liquid; In a regenerator, the treatment liquid having absorbed the acidic compounds is heated to separate the acidic compounds from the treatment liquid; removing moisture contained in the separation-promoting gas from a separation-promoting gas that is a gas that is substantially insoluble and inactive in the treatment liquid and that is composed of a moisture-containing gas or water vapor; The separation-promoting gas from which moisture has been removed is supplied to the regenerator.

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