Gas treatment device and gas treatment method

Abstract

This gas treatment device comprises: an absorption-side reservoir that stores a treatment liquid which has been phase-separated into a first phase portion and a second phase portion in an absorber; a first detector for detecting whether or not a liquid-liquid interface between the first phase portion and the second phase portion falls within a predetermined range in the absorption-side reservoir; a second detector for detecting whether or not a liquid surface of the second phase portion falls within a predetermined range in the absorption-side reservoir; a first flow rate adjustment mechanism that adjusts, on the basis of a detection result by the first detector, a flow rate of the first phase portion to be sent from the absorption-side reservoir to a regenerator such that the liquid-liquid interface falls within the predetermined range; and a second flow rate adjustment mechanism that adjusts, on the basis of a detection result by the second detector, a flow rate of the second phase portion to be sent from the absorption-side reservoir to the regenerator such that the liquid level of the second phase portion falls within the predetermined range.

Description

Gas treatment device and gas treatment method

[0001] The present invention relates to a gas processing device and a gas processing method.

[0002] In recent years, carbon dioxide is thought to have a significant impact on global warming. Carbon dioxide separation and capture technology has attracted attention as an effective measure to combat this global warming problem. While there are various methods for separating and capturing CO2 from CO2 emission sources, such as power plants and steelworks, chemical absorption is suitable for large-scale operations where the emitted CO2 is at near-normal pressure. In this chemical absorption method, acidic CO2 is absorbed into an alkaline aqueous solution (treatment liquid), such as an amine aqueous solution, and the CO2-absorbed treatment liquid is heated. This allows the CO2 in the treatment liquid to be released from the treatment liquid (called the regeneration process), and the separated CO2 is then captured.

[0003] In this type of amine absorption method, a large amount of heat energy is required because heating is required to dissipate CO2 from the CO2-absorbed treated liquid. Furthermore, the heating temperature must be 100°C or higher. This increases the cost required for CO2 separation and capture.

[0004] Therefore, the following Patent Documents 1 and 2 disclose gas treatment devices that achieve energy savings by using a treatment liquid that can be regenerated at low temperatures. Patent Document 1 discloses that a regeneration temperature of 100°C or less can be achieved by using a treatment liquid that separates into two phases, a high CO2 content phase and a low CO2 content phase, upon absorption of CO2. The treatment liquid is an alkaline liquid containing water, an amine compound, and an organic solvent. Patent Document 2 also discloses that the regeneration temperature can be further reduced by supplying a separation-promoting gas in the regeneration step that is substantially insoluble in the treatment liquid and is composed of any one of a hydrocarbon gas such as methane gas, hydrogen gas, and oxygen gas.

[0005] The amine absorption method faces the challenge of fluctuations in the composition of the treated liquid, regardless of whether or not the treated liquid exhibits phase separation behavior, due to factors such as moisture carried into the system, evaporation of treated liquid components (mainly amines), and loss of liquid components due to mist generation from the treated liquid. Because fluctuations in the treated liquid composition can make it difficult to maintain separation performance, it is desirable to control the treated liquid composition to a constant value as much as possible. Furthermore, when the amine-based treated liquid contains organic solvent components such as ether, phase separation occurs in the treated liquid depending on the amount of CO2 absorbed. Therefore, it is necessary to prevent uneven liquid composition at each spot in the gas treatment device. More specifically, if the discharge flow rate ratio of each phase is not properly controlled, the amine phase may accumulate in the absorber, resulting in a relatively high amine concentration. Meanwhile, the amine concentration may decrease in the regenerator, resulting in a high ether concentration. This potential for uneven liquid composition at each spot can occur.

[0006] Incidentally, Patent Document 3 listed below discloses a control method for an amine absorption method using an amine-based treatment liquid that does not undergo two-phase separation even upon CO2 absorption. The control method involves a decarbonation system having an amine recovery section (water washing section) that recovers amines from exhaust gas and a water storage tank that extracts amine-containing water from the amine recovery section. In the decarbonation system, the liquid level of the treatment liquid is adjusted to be constant when the amine-containing water stored in the water storage tank is sent to the carbon dioxide absorption section. This maintains a constant concentration of the treatment liquid.

[0007] Patent No. 6906761 Patent No. 6906766 Patent No. 3364103

[0008] An object of the present invention is to prevent the liquid composition from becoming unbalanced in the absorber and the regenerator.

[0009] A gas treatment device according to one aspect of the present invention is a gas treatment device for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the gas treatment device comprising: an absorber that brings the gas to be treated and the treatment liquid into contact with each other to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; and a regenerator that separates the first phase portion and the second phase portion in the absorber. a first detector for detecting whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range; a second detector for detecting whether a liquid level of the second phase portion in the absorption-side reservoir is within a predetermined range; a first flow rate adjustment mechanism for adjusting a flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the first detector so that the liquid-liquid interface is within the predetermined range; and a second flow rate adjustment mechanism for adjusting a flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the second detector so that the liquid level of the second phase portion is within the predetermined range.

[0010] A gas treatment device according to another aspect of the present invention is a gas treatment device for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that, before absorbing the acidic compounds, is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the gas treatment device including: an absorber that brings the gas to be treated and the treatment liquid into contact with each other, and absorbs the acidic compounds contained in the gas to be treated into the treatment liquid; a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; a regeneration side reservoir into which the treatment liquid heated in the regenerator is introduced, the regeneration side reservoir having an introduction liquid space in which the introduced treatment liquid is stored and a regeneration liquid space that receives regenerated treatment liquid from the introduction liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; and an unregenerated liquid return mechanism that returns the unregenerated treatment liquid that accumulates in the introduction liquid space to the regenerator when the treatment liquid contains unregenerated treatment liquid.

[0011] A gas treatment method according to another aspect of the present invention is a gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the method comprising: bringing the gas to be treated and the treatment liquid into contact with each other in an absorber to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; storing the treatment liquid that has been phase-separated into the first phase portion and the second phase portion in the absorber in an absorption-side reservoir; the treatment liquid sent from the absorption-side reservoir is heated in a regenerator to separate acidic compounds from the treatment liquid; a first detector is used to detect whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range; a second detector is used to detect whether a liquid level of the second phase portion in the absorption-side reservoir is within a predetermined range; based on the detection result by the first detector, the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator is adjusted so that the liquid-liquid interface falls within the predetermined range; and based on the detection result by the second detector, the flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator is adjusted so that the liquid level of the second phase portion falls within the predetermined range.

[0012] A gas treatment method according to another aspect of the present invention is a gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acids when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the method comprising: bringing the gas to be treated and the treatment liquid into contact with each other in an absorber to release the acidic compounds contained in the gas to be treated; The substance is absorbed into the treatment liquid, the treatment liquid sent from the absorber is heated in a regenerator to separate acidic compounds from the treatment liquid, the treatment liquid heated in the regenerator is introduced into a regeneration side reservoir, the introduced treatment liquid is stored in an introduction liquid space in the regeneration side reservoir, and even if the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid, the regenerated treatment liquid is allowed to flow from the introduction liquid space into the regeneration liquid space, and if the treatment liquid contains unregenerated treatment liquid, the unregenerated treatment liquid that has accumulated in the introduction liquid space is returned to the regenerator.

[0013] FIG. 1 is a diagram schematically showing a gas treatment device according to a first embodiment. FIG. 2 is a diagram schematically showing the configuration of an absorption-side reservoir provided in the gas treatment device. FIG. 3 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the inlet-side space of the absorption-side reservoir. FIG. 4 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the space adjacent to the absorption-side reservoir. FIG. 5 is a diagram schematically showing a modified absorption-side reservoir. FIG. 6 is a diagram schematically showing a modified absorption-side reservoir. FIG. 7 is a diagram partially showing a gas treatment device according to a modified first embodiment. FIG. 8 is a diagram schematically showing an absorption tower provided in a gas treatment device according to a second embodiment. FIG. 9 is a diagram schematically showing a modified absorption tower. FIG. 10 is a diagram schematically showing a gas treatment device according to a third embodiment. FIG. 11 is a diagram schematically showing the configuration of a regeneration-side reservoir provided in the gas treatment device. FIG. 12 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the inlet-side space of the regeneration-side reservoir. FIG. 13 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the space adjacent to the regeneration-side reservoir. FIG. 14 is a diagram schematically showing a modified regeneration-side reservoir. FIG. 10 is a diagram schematically showing a regeneration tower provided in a gas treatment device according to a fourth embodiment. FIG. 11 is a diagram schematically showing a gas treatment device according to a fifth embodiment. FIG. 12 is a diagram schematically showing the configuration of a regeneration-side reservoir provided in the gas treatment device. FIG. 13 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the introduction liquid space of the regeneration-side reservoir. FIG. 14 is a diagram for explaining a method for adjusting the amount of treatment liquid stored in the regeneration liquid space of the regeneration-side reservoir. FIG. 15 is a diagram schematically showing the configuration of an absorption-side reservoir provided in the gas treatment device. FIG. 16 is a diagram schematically showing a modified example of the absorption-side reservoir provided in the gas treatment device.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] First Embodiment As shown in FIG. 1 , a gas treatment device 10 according to a first embodiment separates acidic compounds from a gas to be treated that contains the acidic compounds using a treatment liquid that reversibly absorbs and releases the acidic compounds. In this embodiment, carbon dioxide (CO2), an acidic compound that generates an acid when dissolved in water, is the target of separation, making this device effective as a measure against global warming. The acidic compound is not particularly limited as long as it produces an acidic aqueous solution, and may be, for example, hydrogen chloride, carbon dioxide, sulfur dioxide, carbon disulfide, or the like. Examples of gases to be treated that contain acidic compounds include industrial exhaust gases, process gases generated during refining, and natural gas.

[0016] The treatment liquid is a treatment liquid in which a first component (amine) and a 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 may be, for example, an alkaline absorbent containing water, an amine, and an organic solvent as the second component, and may contain 30 wt % of amine, 60 wt % of organic solvent, and 10 wt % of water.

[0017] As the 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.

[0018] As the 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.

[0019] 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. On the other hand, upon absorption of the acidic compound, the treatment liquid undergoes phase separation into a first phase portion containing mainly the first component (amine) with a high acidic compound content, and a second phase portion containing mainly the second component with a low acidic compound content. Here, the solubility parameter is expressed by the following formula (1):

[0020]

[0021] ΔH is the molar latent heat of vaporization, R is the gas constant, T is the absolute temperature, and V is the molar volume.

[0022]

[0023] As shown in Table 1, in an absorbent containing water, an amine, and an organic solvent, the value obtained by subtracting the solubility parameter of the organic solvent from the solubility parameter of the amine was 1.1 (cal / cm ３ ) １／２ More than 4.2 (cal / cm ３ ) １／２ By selecting the combination of amine and organic solvent as shown below, a treatment liquid is obtained that, upon absorption of the acidic compound, separates into two phases: a first phase that has a high acidic compound content and mainly contains amine, and a second phase that has a low acidic compound content and mainly contains a 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.

[0024] If the value of the difference in solubility parameters is less than the lower limit, the treatment liquid may not separate into two phases even after absorbing the acidic compound. On the other hand, if the value of the difference in solubility parameters exceeds the upper limit, the treatment liquid may separate into two phases before absorbing the acidic compound. In this case, in the step of contacting the treatment liquid with the gas to be treated containing the 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 there was a single liquid phase before absorbing carbon dioxide and that separation into two liquid phases occurred upon absorption of carbon dioxide. Also, "immiscible" in Table 1 means that there was a two-liquid phase state before absorbing carbon dioxide and that a single liquid phase did not form. Also, "not separated" in Table 1 means that there was a single liquid phase even after absorbing carbon dioxide.

[0025] 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 that brings a gas to be treated, such as a process gas, into contact with a treatment liquid, thereby causing the treatment liquid to absorb acidic compounds in the gas to be treated. In this embodiment, carbon dioxide, which is an acidic compound, is separated from the gas to be treated.

[0026] 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 that heats the rich liquid to release carbon dioxide from 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.

[0027] The absorber 12 is connected to an inlet line 22 that supplies the gas to be treated to the absorber 12, an outlet line 24 that discharges the gas after treatment (treated gas), a feed line 16 that sends the treated liquid to the regenerator 14, and a return line 18 that returns the treated liquid from the regenerator 14 to the absorber 12. The inlet line 22 is connected to the bottom of the absorber 12, and the discharge line 24 is connected to the top of the absorber 12. The feed line 16 is connected to the bottom of the absorber 12. That is, the feed line 16 is connected to the absorber 12 at a position where the treated liquid accumulated in the absorber 12 can be extracted. The return line 18 is connected to the top of the absorber 12. That is, the return line 18 is connected to the absorber 12 at a position where the treated liquid can flow downward within the absorber 12.

[0028] In the absorber 12, the gas to be treated introduced through the inlet line 22 comes into contact with the treatment liquid that has returned through the return line 18. As a result, the carbon dioxide in the gas to be treated is absorbed by the treatment liquid. In addition, the treated gas, which is the gas from which the 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.

[0029] 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 an absorption-side reservoir 26 that stores the phase-separated treated liquid (rich liquid) separately into a treated liquid mainly containing the first phase portion and a treated liquid mainly containing the second phase portion. The absorption-side reservoir 26 is configured to separate the first phase portion and the second phase portion using the difference in specific gravity between them.

[0030] The feed flow path 16 includes an upstream section 16a, a first flow path section 16b, a second flow path section 16c, and a downstream section 16d. The upstream section 16a connects the absorber 12 and the absorption-side reservoir 26 to each other. The first flow path section 16b is connected to an inlet-side space 26a (described below) in the absorption-side reservoir 26, and allows the treated liquid (first phase portion) to be discharged from the inlet-side space 26a. The second flow path section 16c is connected to an adjacent space 26b (described below) in the absorption-side reservoir 26, and allows the treated liquid (second phase portion) to be discharged from the adjacent space 26b. The downstream section 16d is where the first flow path section 16b and the second flow path section 16c join, and is connected to the regenerator 14.

[0031] As shown in FIG. 2 , the space within the absorption-side reservoir 26 is partitioned by a partition member 27 into an inlet-side space 26a, which is a first space, and an adjacent space 26b, which is a second space. The treated liquid introduced into the absorption-side reservoir 26 through the feed channel 16 is introduced into the inlet-side space 26a. The treated liquid that has flowed into the inlet-side space 26a is in a phase-separated state. Therefore, the second phase portion of the treated liquid, which has a lower specific gravity, flows over the upper end of the partition member 27 and is introduced into the adjacent space 26b. Therefore, 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, within the absorption-side reservoir 26, the treated liquid is separated into a treated liquid mainly containing the first phase portion and a treated liquid mainly containing the second phase portion.

[0032] A first detector 31 is provided in the inlet space 26a to detect whether the liquid-liquid interface between the first and second phases is within a predetermined range. The first detector 31 may be any type of sensor or switch that can be used to monitor the position of the liquid-liquid interface. For example, an electrode-type level switch, a float-type level switch, a capacitance-type level switch, an optical level switch, a guided pulse level sensor, or other such sensor or switch may be used. The liquid-liquid interface may be directly detected by a sensor, or the upper and lower limits of the liquid-liquid interface may be detected by a pair of level switches. Note that FIG. 2 shows an example in which the liquid-liquid interface is monitored by a pair of level switches.

[0033] The first flow path section 16b is provided with a first flow rate adjustment mechanism 28 for adjusting the flow rate of the first phase portion sent from the absorption-side reservoir 26 to the regenerator 14. The first flow rate adjustment mechanism 28 is configured to be able to adjust the flow rate based on the detection result by the first detector 31. Therefore, by controlling the first flow rate adjustment mechanism 28, the height of the liquid-liquid interface between the first and second phase portions falls within a predetermined range. As a result, the amount of the first phase portion stored in the absorption-side reservoir 26 is adjusted to a predetermined amount.

[0034] The first detector 31 constantly monitors the liquid-liquid interface, and the first flow rate adjustment mechanism 28 is configured to adjust the flow rate each time based on the detection result by the first detector 31. For this reason, the first flow rate adjustment mechanism 28 includes a pump and a controller, and the controller is configured to control the pump based on a signal from the first detector 31.

[0035] A second detector 32 is provided in the adjacent space 26b to detect whether the liquid level of the second phase portion is within a predetermined range. The second detector 32 may be any type of sensor or switch that can be used to detect the position of the liquid level. For example, an electrode-type level switch, a float-type level switch, a capacitance-type level switch, an optical level switch, a guided pulse level sensor, or other such sensor or switch may be used. The liquid level may be directly detected by a sensor, or the upper and lower limits of the liquid level may be detected by a pair of level switches.

[0036] The second flow path section 16c is provided with a second flow rate adjustment mechanism 29 that adjusts the flow rate of the second phase portion sent from the absorption-side reservoir 26 to the regenerator 14. The second flow rate adjustment mechanism 29 is configured to control the flow rate based on the detection result by the second detector 32. Therefore, by controlling the second flow rate adjustment mechanism 29, the liquid level of the second phase portion in the adjacent space 26b falls within a predetermined range. As a result, the amount of the second phase portion stored in the absorption-side reservoir 26 is adjusted to a predetermined amount.

[0037] The second detector 32 constantly monitors the liquid level, and the second flow rate adjustment mechanism 29 is configured to adjust the flow rate each time based on the detection result by the second detector 32. Therefore, the second flow rate adjustment mechanism 29 includes a pump and a controller, and the controller is configured to control the pump based on a signal from the second detector 32.

[0038] A heat exchanger 34 is provided in the downstream portion 16d of the feed flow path 16. The heat exchanger 34 is for exchanging heat 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 through the return flow path 18. The heat exchanger 34 may be omitted.

[0039] 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 the upper part of the regenerator 14. The return flow path 18 is connected to the lower part of the regenerator 14. A pump 35 is provided in the return flow path 18.

[0040] 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 from the treatment liquid, but water in the treatment liquid also evaporates. Note that desorption of carbon dioxide from the treatment liquid is an endothermic reaction.

[0041] A supply line 38 is connected to the regenerator 14 for supplying the carbon dioxide-containing gas obtained in the regenerator 14 to a carbon dioxide consumer. A separation-promoting gas for promoting separation of acidic compounds from the treatment liquid in the regenerator 14 may also be supplied to the regenerator 14. The separation-promoting gas is a hydrocarbon gas such as hydrogen gas, oxygen gas, or methane gas, or water vapor, etc.

[0042] Here, a gas processing method using the gas processing device 10 according to the first embodiment will be described. The gas processing method includes an absorption step and a regeneration step.

[0043] The absorption step is a step in which the gas to be treated is brought into contact with a 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 reflux 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 with a high carbon dioxide content and a second phase portion with a low carbon dioxide content.

[0044] The treated liquid in the absorber 12 is introduced into the inlet-side space 26a of the absorption-side reservoir 26 through the upstream section 16a of the feed flow path 16. Since the treated liquid introduced into the absorption-side reservoir 26 is in a phase-separated state, the treated liquid is stored in the inlet-side space 26a so that the second phase (mainly containing organic solvents) with a lower specific gravity than the first phase is located above the first phase (mainly containing amine). Then, part of the second phase of the treated liquid exceeds the upper end of the partition member 27 and is introduced into the adjacent space 26b.

[0045] In the inlet space 26a, a first detector 31 monitors whether the liquid-liquid interface between the first and second phases is within a predetermined range, and in the adjacent space 26b, a first detector 31 monitors whether the liquid level of the second phase is within a predetermined range.

[0046] Here, a method for adjusting the amount of treatment liquid stored in the inlet-side space 26a and the adjacent space 26b will be described with reference to Figures 3 and 4. Figure 3 shows a method for adjusting the amount of treatment liquid stored in the inlet-side space 26a and the adjacent space 26b when the first detector 31 is configured with a pair of level switches (upper limit switch 31a and lower limit switch 31b).

[0047] First, it is determined whether the lower limit switch 31b is detecting the gas phase, the first phase portion, or the second phase portion (step ST11).

[0048] If it is determined that the lower limit switch 31b detects the first phase portion, the process proceeds to step ST12, where it is determined whether the upper limit switch 31a detects the gas phase, the first phase portion, or the second phase portion. If it is determined that the upper limit switch 31a detects the first phase portion, the amount of stored first phase portion is too large. Therefore, the first flow rate adjustment mechanism 28 is adjusted so that the flow rate of the first flow rate adjustment mechanism 28 increases by a predetermined amount (step ST13). On the other hand, if it is determined that the upper limit switch 31a detects the second phase portion, the amount of stored first phase portion is within the appropriate range. Therefore, the flow rate of the first flow rate adjustment mechanism 28 is not changed (step ST14). On the other hand, if it is determined that the upper limit switch 31a detects the gas phase, the amount of stored first and second phase portions is too small. Therefore, the first flow rate adjustment mechanism 28 is adjusted so that the flow rate of the first flow rate adjustment mechanism 28 decreases by a predetermined amount (step ST15).

[0049] On the other hand, if it is determined in step ST11 that the lower limit switch 31b has detected the second phase portion, the amount of the first phase portion stored is too small, and therefore the first flow rate adjustment mechanism 28 is adjusted so that the flow rate of the first flow rate adjustment mechanism 28 is reduced by a predetermined amount (step ST21).

[0050] If it is determined in step ST11 that the lower limit switch 31b detects the gas phase, the amount of the first and second phases stored is too small, and the first flow rate adjustment mechanism 28 is adjusted so that the flow rate of the first flow rate adjustment mechanism 28 is reduced by a predetermined amount (step ST22).

[0051] The first phase portion at the flow rate adjusted in this manner is sent from the inlet side space 26a to the first flow path portion 16b.

[0052] 4, the second flow rate adjustment mechanism 29 adjusts the flow rate so that the liquid level of the second phase portion detected by the second detector 32 falls within a predetermined range (preferably so that it is constant) (step ST31). That is, when the liquid level of the second phase portion is higher than the predetermined range, the flow rate by the second flow rate adjustment mechanism 29 is increased, and when the liquid level is lower than the predetermined range, the flow rate by the second flow rate adjustment mechanism 29 is reduced.

[0053] The second phase portion at the flow rate adjusted in this manner is sent from the adjacent space 26b to the second flow path section 16c. That is, the first phase portion mainly containing amine is discharged through the first flow path section 16b, and the second phase portion mainly containing the second component (organic solvent) is discharged through the second flow path section 16c. At this time, the first flow rate adjustment mechanism 28 and the second flow rate adjustment mechanism 29 adjust the ratio of the first phase portion to the second phase portion in the absorption-side reservoir 26 to fall within a predetermined range. This prevents imbalances in the liquid composition in the absorber 12 and the regenerator 14.

[0054] The first-phase portion and the second-phase portion join together in the downstream section 16d and are heated in the heat exchanger 34 by heat exchange with the treatment liquid (lean liquid) flowing through the reflux line 18. The treatment liquid that has passed through the heat exchanger 34 is introduced into the regenerator 14.

[0055] The treated liquid introduced into the regenerator 14 is heated by a heater 36, thereby separating carbon dioxide from the treated liquid (regeneration step). The carbon dioxide separated from the treated liquid is sent to a consumer via a supply line 38.

[0056] 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 34.

[0057] As described above, in this embodiment, when the treatment liquid absorbs the acidic compounds in the absorber 12, the treatment liquid undergoes phase separation into a first-phase portion containing mainly the first component and a second-phase portion containing mainly the second component. This phase-separated treatment liquid is stored in the absorption-side reservoir 26. In the absorption-side reservoir 26, the second-phase portion containing mainly the second component with a lower specific gravity accumulates above the first-phase portion containing mainly the first component. As a result, a liquid-liquid interface between the first and second phases is formed in the absorption-side reservoir 26. The first flow rate adjustment mechanism 28 adjusts the flow rate of the first-phase portion sent from the absorption-side reservoir 26 to the regenerator 14 so that this liquid-liquid interface falls within a predetermined range, and the second flow rate adjustment mechanism 29 adjusts the flow rate of the second-phase portion sent from the absorption-side reservoir 26 to the regenerator 14 so that the liquid level of the second-phase portion falls within a predetermined range. Therefore, by utilizing the fact that the first phase portion and the second phase portion accumulate in layers in the absorption-side reservoir 26, the ratio of the first phase portion to the second phase portion accumulated in the absorption-side reservoir 26 is adjusted to be within a predetermined range. Therefore, for example, when the ratio of the first phase portion is high in the absorber 12 and the ratio of the second phase portion is high in the regenerator 14, a larger amount of the first phase portion is introduced into the absorption-side reservoir 26. In this case, the first flow rate adjustment mechanism 28 is adjusted to send out a larger amount of the first phase portion from the absorption-side reservoir 26. Therefore, it is possible to suppress the occurrence of an imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber 12 and the regenerator 14.

[0058] In this embodiment, the space within the absorption-side reservoir 26 is divided by the partition member 27 into an inlet-side space 26a, which is a first space that stores the phase-separated treatment liquid, and an adjacent space 26b, which is a second space that stores only the second phase portion. Therefore, the second flow rate control mechanism 29 can prevent the first phase portion from being sent out, making it easy to adjust the flow rates using the first flow rate control mechanism 28 and the second flow rate control mechanism 29.

[0059] In this embodiment, the first detector 31 is configured with a pair of level switches. However, as shown in FIG. 5, the first detector 31 may instead be configured with a level sensor that can directly detect the liquid-liquid interface. In this case, when the first detector 31 does not detect the liquid-liquid interface, i.e., when the amount of the first phase portion stored is too small, the first flow rate adjustment mechanism 28 is adjusted to reduce the flow rate of the liquid discharged from the inlet-side space 26a. On the other hand, when the first detector 31 detects the liquid-liquid interface, if the liquid-liquid interface is lower than a predetermined position, the first flow rate adjustment mechanism 28 is adjusted to reduce the flow rate of the liquid discharged from the inlet-side space 26a, and if the liquid-liquid interface is higher than the predetermined position, the first flow rate adjustment mechanism 28 is adjusted to increase the flow rate of the liquid discharged.

[0060] In the above embodiment, the space within the absorption-side reservoir 26 is divided into the inlet-side space 26a and the adjacent space 26b, but this configuration is not limited thereto. For example, as shown in Fig. 6, the space within the absorption-side reservoir 26 may be formed as a single space, and the treatment liquid may be stored within this space. In this case, a conduit 40 is inserted into the absorption-side reservoir 26, and the second flow path section 16c is connected to this conduit 40. The upper end of the conduit 40 is set at a position that allows the second phase portion to flow in. The first detector 31 is configured by a level sensor that detects the liquid-liquid interface, and the second detector 32 is configured by a level sensor that detects the liquid level of the second phase portion.

[0061] In this case, the first flow rate adjustment mechanism 28 adjusts the flow rate of the liquid discharged from the absorption-side reservoir 26 so that the liquid-liquid interface remains at a constant level. The second flow rate adjustment mechanism 29 adjusts the flow rate of the liquid discharged from the absorption-side reservoir 26 so that the liquid level of the second phase portion remains at a constant level. Because the upper end of the conduit 40 is located at a height corresponding to the second phase portion, the conduit 40 can discharge only the second phase portion.

[0062] Furthermore, when the space inside the absorption-side reservoir 26 is not partitioned into the inlet-side space 26a and the adjacent space 26b, the first flow path section 16b may be connected to the bottom of the absorption-side reservoir 26, and the second flow path section 16c may be connected to the top of the absorption-side reservoir 26. In this case, the conduit 40 can be omitted.

[0063] 7, the reflux path 18 may be provided with a component measuring device 42 and a replenishment container 43. The component measuring device 42 is configured to be able to measure the composition ratios of the amine, the second component (organic solvent), and water in the treatment liquid (lean liquid). When it is confirmed that the treatment liquid has been sufficiently regenerated, the replenishment container 43 can replenish the missing components based on the composition ratios measured by the component measuring device 42. A flow rate controller 44 may be provided in the reflux path 18.

[0064] Second Embodiment Fig. 8 shows a second embodiment. 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.

[0065] In the second embodiment, the absorption-side reservoir 26 is configured integrally with the absorber 12. That is, an absorption tower 46 is configured including the absorber 12 and the absorption-side reservoir 26 provided below the absorber 12. In the absorption tower 46, the space inside the absorber 12 and the space inside the absorption-side reservoir 26 are configured as one continuous space.

[0066] The top plate 47 of the absorption-side reservoir 26 is configured to guide the treatment liquid (treatment liquid that has absorbed acidic compounds) in the absorber 12 so as to prevent the treatment liquid from flowing into the adjacent space 26b of the absorption-side reservoir 26. The treatment liquid in the absorber 12 is introduced into the inlet-side space 26a of the absorption-side reservoir 26 through the gap between the top plate 47 and the side wall of the absorption-side reservoir 26. A first flow path section 16b is connected to the inlet-side space 26a, and a second flow path section 16c is connected to the adjacent space 26b. The feed flow path 16 does not have an upstream section 16a.

[0067] The partition member 27 separating the inlet-side space 26a from the adjacent space 26b may be omitted. In this case, as shown in Figure 9, a conduit 40 is inserted into the absorption-side reservoir 26, and the second flow path section 16c is connected to this conduit 40. The upper end of the conduit 40 is set at a position that allows the second phase portion to flow in. As a result, only the second phase portion flows into the second flow path section 16c through the conduit 40. On the other hand, the first flow path section 16b is connected to the bottom of the absorption-side reservoir 26. Therefore, the first phase portion in the absorption-side reservoir 26 flows out of the absorption-side reservoir 26 through the first flow path section 16b.

[0068] Although the description of other configurations, actions, and effects will be omitted, the description of the first embodiment can be applied to the second embodiment.

[0069] 10 and 11, in the third embodiment, a regeneration-side reservoir 50 is added. Note that the same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0070] The regeneration-side reservoir 50 is provided in the reflux path 18, and receives the treatment liquid heated in the regenerator 14. The space within the regeneration-side reservoir 50 is divided by a partition member 51 into an introduction liquid space 50a and a regeneration liquid space 50b. The introduction liquid space 50a is further divided by an auxiliary partition 52 into an inlet-side space 50a1 and an adjacent space 50a2. The introduction liquid space 50a is received in the introduction-side space 50a1 (introducing liquid space 50a). The treatment liquid discharged from the regenerator 14 is received in the introduction-side space 50a1 (the introduction liquid space 50a). This treatment liquid includes the regenerated treatment liquid (regenerated liquid) regenerated in the regenerator 14. However, if the regeneration of the treatment liquid in the regenerator 14 does not keep up with the demand, treatment liquid containing acidic compounds may be generated without being regenerated (unregenerated liquid). In this case, the treatment liquid introduced into the regeneration-side reservoir 50 includes the unregenerated liquid. Because the unregenerated liquid contains acidic compounds, it is phase-separated into a first phase and a second phase. On the other hand, the regenerated liquid does not undergo phase separation. The first phase, which mainly contains amine, separates from the regenerated liquid, while the second phase, which mainly contains the second component (organic solvent), mixes with the regenerated liquid. Therefore, when unregenerated liquid is generated, the first phase of the unregenerated liquid accumulates below the regenerated liquid (regenerated phase) mixed with the second phase in the inlet space 50a1. Note that in the regenerated liquid mixed with the second phase, the proportion of the regenerated phase is higher at the bottom and the proportion of the second component is higher at the top.

[0071] The partition member 51 has a communication hole 51a that connects the inlet-side space 50a1 and the regenerated liquid space 50b. This communication hole 51a is located at a position in the inlet-side space 50a1 where the proportion of the regenerated phase or regenerated liquid in the treatment liquid is high. That is, the first unregenerated liquid detector 55 and the first return mechanism 57, described below, adjust the liquid-liquid interface between the first phase and the regenerated liquid to a predetermined range. Therefore, when a predetermined amount of treatment liquid accumulates in the inlet-side space 50a1, the height position of the regenerated phase also tends to fall within a predetermined range. Therefore, the communication hole 51a is located at a position where the proportion of the regenerated phase or regenerated liquid in the treatment liquid is high. Therefore, the regenerated treatment liquid (the regenerated phase in the regenerated liquid) that accumulates in the inlet-side space 50a1 flows into the regenerated liquid space 50b. Therefore, the regenerated liquid accumulates in the regenerated liquid space 50b. Note that the regenerated liquid does not necessarily flow into the regenerated liquid space 50b all the time. Therefore, when the proportion of the second phase portion mixed with the regenerated liquid is high, the second phase portion of the unregenerated liquid may also flow into the regenerated liquid space 50b.

[0072] When unregenerated liquid is generated, the treated liquid (mainly the second phase portion) that has accumulated in the inlet space 50a1 and exceeds the upper end of the auxiliary partition 52 is introduced into the adjacent space 50a2. Therefore, the second phase portion of the unregenerated liquid is mainly accumulated in the adjacent space 50a2.

[0073] The inlet space 50a1 (introducing liquid space 50a) is provided with a first unregenerated liquid detector 55 for detecting whether a predetermined amount or more of the first phase portion of the unregenerated liquid has accumulated. The first unregenerated liquid detector 55 may be any type of sensor or switch that can be used to monitor the position of the liquid-liquid interface between the first phase portion and the regenerated liquid. For example, an electrode-type level switch, a float-type level switch, a capacitance-type level switch, an optical level switch, a guided pulse level sensor, or other sensors or switches may be used. The liquid-liquid interface may be directly detected by a sensor, or a pair of level switches may be used to detect the upper and lower limits of the liquid-liquid interface. Note that, since it is preferable that the unregenerated first phase portion accumulate as little as possible in the introducing liquid space 50a, the first unregenerated liquid detector 55 is preferably configured to detect the liquid-liquid interface between the first phase portion and the regenerated liquid even when the interface is at a low position.

[0074] A first return path 56 that connects the inlet-side space 50a1 and the regenerator 14 is connected to the regenerator-side reservoir 50. The first return path 56 is provided with a first return mechanism 57 for returning the first phase portion in the inlet-side space 50a1 to the regenerator 14. The first return path 56 may be provided with a heat exchanger for heating the first phase portion.

[0075] A second unregenerated liquid detector 58 is provided in the adjacent space 50a2 to detect whether the liquid level of the second phase portion of the unregenerated liquid is within a predetermined range. The second unregenerated liquid detector 58 may be any type of sensor or switch that can be used to detect the liquid level of the second phase portion. For example, an electrode-type level switch, a float-type level switch, a capacitance-type level switch, an optical level switch, a guided pulse level sensor, or other sensors or switches may be used. The liquid level may be detected directly by a sensor, or the upper and lower limits of the liquid level may be detected by a pair of level switches. Note that the second unregenerated liquid detector 58 may be omitted because the flow rate of the second return mechanism 60 (described below) can be set as desired.

[0076] A second return path 59 that connects the adjacent space 50a2 and the regenerator 14 is connected to the regenerator-side reservoir 50. The second return path 59 is provided with a second return mechanism 60 for returning the second phase portion in the adjacent space 50a2 to the regenerator 14. The second return path 59 may be provided with a heat exchanger for heating the second phase portion.

[0077] The first return mechanism 57 and the second return mechanism 60 constitute an unregenerated liquid return mechanism that returns the unregenerated treatment liquid accumulated in the introduction liquid space 50 a from the regeneration side reservoir 50 to the regenerator 14 .

[0078] Here, a method for adjusting the amount of treatment liquid stored in the inlet-side space 50a1 and the adjacent space 50a2 of the regeneration-side reservoir 50 will be described with reference to FIGS.

[0079] In the inlet-side space 50a1, the first unregenerated liquid detector 55 monitors whether the liquid-liquid interface between the first phase portion and the regenerated liquid is within a predetermined range (step ST41). When the first unregenerated liquid detector 55 detects the first phase portion, the first return mechanism 57 is activated (step ST42). That is, since it is determined that the amount of the first phase portion of the unregenerated liquid accumulating in the regeneration-side reservoir 50 is excessive, the first return mechanism 57 is activated and returns the first phase portion of the unregenerated liquid from the inlet-side space 50a1 to the regenerator 14. This adjusts the amount of the first phase portion of the unregenerated liquid accumulating in the regeneration-side reservoir 50 to a predetermined amount. The unregenerated liquid returned to the regenerator 14 is reheated in the regenerator 14. Note that, since it is desirable for almost no first phase portion to accumulate in the regeneration-side reservoir 50, the "predetermined amount" is preferably an amount close to zero.

[0080] In the adjacent space 50a2, the second unregenerated liquid detector 58 monitors whether the liquid level of the treatment liquid (mainly the second phase portion present in the adjacent space 50a2) is below a predetermined level (step ST51). If the second unregenerated liquid detector 58 determines that the liquid level is higher than the predetermined range, the second return mechanism 60 is adjusted to increase the flow rate (step ST52). As a result, the unregenerated second phase portion is returned to the regenerator 14 and reheated. Furthermore, the liquid level of the treatment liquid in the adjacent space 50a2 remains below a certain level. If the second unregenerated liquid detector 58 is omitted, the flow rate of the second return mechanism 60 can be set arbitrarily.

[0081] The flow rate of the pump 35 that draws the regenerant liquid from the regenerant liquid space 50b can be set arbitrarily by the user.

[0082] In this embodiment, the first return mechanism 57 and the second return mechanism 60 are operated to return the unregenerated treatment liquid from the regeneration-side reservoir 50 to the regenerator 14. By operating the return mechanisms 57 and 60, at least a portion of the unregenerated treatment liquid is returned to the regenerator 14. Therefore, even if unregenerated treatment liquid is generated in the regenerator 14 and accumulates in the regeneration-side reservoir 50, this unregenerated treatment liquid is returned to the regenerator 14 and heated again. This promotes the regeneration of the unregenerated treatment liquid. This prevents treatment liquid with a composition ratio different from that of the treatment liquid initially charged from returning to the absorber 12, thereby suppressing fluctuations in the ratio of the first phase and the second phase contained in the treatment liquid circulating between the regenerator 14 and the absorber 12. This further suppresses imbalances between the first component (first phase) and the second component (second phase) between the absorber 12 and the regenerator 14.

[0083] In this embodiment, the introduction liquid space 50a is divided into an inlet side space 50a1 and an adjacent space 50a2, and a second unregenerated liquid detector 58 is provided in the adjacent space 50a2. The second return mechanism 60 is controlled based on the detection results of the second unregenerated liquid detector 58. However, this configuration is not limited to this. For example, as shown in FIG. 14, the introduction liquid space 50a may be configured as a single space without the auxiliary partition 52. A conduit 62 is inserted into the introduction liquid space 50a, and the inlet (upper end) 62a of the conduit 62 is set at a position where the second phase portion accumulates in the introduction liquid space 50a. The second return path 59 is connected to the introduction liquid space 50a via the conduit 62. In this case, the flow rate of the second return mechanism 60 may be set to any value. The second return mechanism 60 draws in the second phase portion, thereby adjusting the liquid level of the second phase portion to be below the height of the inlet 62a of the conduit 62. The first return mechanism 57 adjusts the flow rate in accordance with the detection result by the first unregenerated liquid detector 55 .

[0084] The conduit 62 may have a bent shape as shown in Figure 15. Even in this case, the position of the inlet 62a is set to a position suitable for allowing the second phase portion to flow in.

[0085] Although the description of other configurations, actions, and effects will be omitted, the descriptions of the first and second embodiments can be applied to the third embodiment.

[0086] 16 shows a fourth embodiment. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0087] In the fourth embodiment, the regenerator-side reservoir 50 is integrally formed with the regenerator 14. That is, a regenerator tower 64 is formed that includes the regenerator 14 and the regenerator-side reservoir 50 provided below the regenerator 14. In the regenerator tower 64, the space inside the regenerator 14 and the space inside the regenerator-side reservoir 50 are formed as one continuous space.

[0088] The top plate 65 of the regeneration-side reservoir 50 is configured to guide the treatment liquid in the regenerator 14 so as to prevent the treatment liquid from flowing into the adjacent space 50a2 in the regeneration-side reservoir 50. The treatment liquid in the regenerator 14 is introduced into the liquid introduction space 50a of the regeneration-side reservoir 50 through an opening 65a formed in the top plate 65. The liquid introduction space 50a may be partitioned into an inlet-side space 50a1 and an adjacent space 50a2, or may be configured as a single space, as in FIG. 14 .

[0089] Although the description of other configurations, actions, and effects will be omitted, the descriptions of the first to third embodiments can be applied to the fourth embodiment.

[0090] Fifth Embodiment The control in the regeneration-side reservoir 50 described with reference to Figures 12 and 13 is based on the assumption that the liquid level control (the control shown in Figure 3) is performed in the absorption-side reservoir 26. In contrast, as shown in Figure 17, a gas treatment device 10 of the fifth embodiment does not include the absorption-side reservoir 26, but includes a regeneration-side reservoir 50. The feed flow path 16 is configured as a single flow path rather than branching into a first flow path portion 16b and a second flow path portion 16c at an intermediate portion. A pump 69 is provided in the feed flow path 16 for sending the treatment liquid to the regenerator 14. Note that the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0091] 11 and 14 to 16 can be adopted as the regeneration-side reservoir 50 in the fifth embodiment. However, in the fifth embodiment, the liquid level control is not performed in the absorption-side reservoir 26, and therefore the liquid level control is performed in the regeneration-side reservoir 50.

[0092] As shown in Figure 18, the regeneration-side reservoir 50 is provided with a first unregenerated liquid detector 55 and a liquid level detector 68. In Figure 18, the auxiliary partition 52 is not provided, and the liquid introduction space 50a is configured as a single space with the conduit 62 inserted therein. Therefore, the second unregenerated liquid detector 58 is not provided. However, it is also possible to provide the auxiliary partition 52 and the second unregenerated liquid detector 58 in a configuration similar to that shown in Figure 11.

[0093] The first unregenerated liquid detector 55 is a detector for detecting whether the first phase portion of the unregenerated liquid has accumulated in a predetermined amount or more, and is arranged in the introduction liquid space 50a (or the inlet side space 50a1).

[0094] The liquid level detector 68 is a detector for detecting whether the liquid level in the regenerator liquid space 50b is within a predetermined range, and is disposed in the regenerator liquid space 50b. Note that, since the regenerator liquid space 50b and the liquid introduction space 50a are in communication with each other through the communication hole 51a, the liquid level detector 68 may be disposed in the liquid introduction space 50a. In other words, the liquid level detector 68 may be a detector for detecting the liquid level of the treatment liquid stored in the regeneration-side reservoir 50.

[0095] The first return mechanism 57 is activated when the first unregenerated liquid detector 55 detects a first phase portion equal to or greater than a predetermined amount. That is, when a liquid-liquid interface between the first phase portion and the regenerated liquid is detected, it is determined that a first phase portion equal to or greater than a predetermined amount has accumulated, and the first return mechanism 57 is activated. When the first return mechanism 57 is activated, the first phase portion in the introduction liquid space 50a is returned to the regenerator 14. Note that, since it is preferable that the first phase portion does not accumulate in the introduction liquid space 50a as much as possible, the first unregenerated liquid detector 55 is preferably configured to be able to detect the liquid-liquid interface between the first phase portion and the regenerated liquid even when the interface is at a low position.

[0096] 18, when a conduit 62 is used, the second return mechanism 60 draws in the corresponding amount of processing liquid (mainly the second phase portion) when the liquid level of the processing liquid (mainly the second phase portion near the liquid level) is higher than the upper end (inlet 62a) of the conduit 62. This makes it possible to adjust the liquid level of the processing liquid to a predetermined value or below.

[0097] The pump 35 adjusts the outflow rate of the regenerated liquid so that the liquid level in the regenerated liquid space 50b falls within a predetermined range based on the detection result by the liquid level detector 68. In other words, the pump 35 and the liquid level detector 68 function as a regenerated liquid flow rate adjustment mechanism 70 that sends the regenerated treated liquid from the regeneration-side reservoir 50 to the absorber 12 so that a predetermined amount of regenerated treated liquid is accumulated in the regeneration-side reservoir 50. Note that when the first unregenerated liquid detector 55 detects a gas phase, the pump 35 is configured to reduce the flow rate.

[0098] Here, a method for adjusting the amount of treatment liquid stored in the regeneration-side reservoir 50 will be described with reference to FIGS.

[0099] As shown in FIG. 19 , in the inlet space 50a (or the inlet space 50a1), the first unregenerated liquid detector 55 monitors the position of the liquid-liquid interface between the first phase of the unregenerated liquid and the regenerated liquid (regenerated liquid mixed with the unregenerated second phase) or the regenerated phase (step ST61). That is, the first unregenerated liquid detector 55 monitors whether the gas phase, the unregenerated first phase, the regenerated liquid (regenerated liquid mixed with the unregenerated second phase) or the regenerated phase is detected. In step ST61, if the regenerated liquid (regenerated liquid mixed with the unregenerated second phase) or the regenerated phase is detected (if the liquid-liquid interface is determined to be within a predetermined range), the flow rate is determined to be appropriate. Therefore, the temperature inside the regenerator 14 is checked (step ST62). If it is within the predetermined temperature range, the flow rate of the first return mechanism 57 is maintained as is, and the heat input by the heater 36 is also maintained (step ST63). On the other hand, if the temperature inside the regenerator 14 exceeds the predetermined range, the flow rate of the first return mechanism 57 is reduced and the amount of heat input by the heater 36 is reduced (step ST64).

[0100] If the first unregenerated liquid detector 55 detects a gas phase in step ST61, the flow rate of the pump 35 is reduced (step ST65). That is, since the first unregenerated liquid detector 55 is used to monitor whether or not a first phase portion is detected, the detection of a gas phase by the first unregenerated liquid detector 55 is considered to indicate the occurrence of some kind of malfunction.

[0101] Furthermore, when it is determined that the first phase portion has been detected by the first unregenerated liquid detector 55 (when it is determined that the liquid-liquid interface is higher than the predetermined range), the first return mechanism 57 is activated (step ST66), and the first phase portion in the introduction liquid space 50a is returned to the regenerator 14. At this time, the amount of heat input by the heater 36 of the regenerator 14 is increased (step ST67).

[0102] Meanwhile, as shown in FIG. 20 , the liquid level detector 68 monitors whether the liquid level in the regenerated liquid space 50b is within a predetermined range (step ST71). If the liquid level is outside the predetermined range, the pump 35 adjusts the flow rate of the regenerated liquid from the regenerator 14 (step ST72). That is, if the liquid level of the regenerated processing liquid rises above the predetermined range, the pump 35 increases its rotation speed. On the other hand, if the liquid level of the regenerated processing liquid falls below the predetermined range, the pump 35 decreases its rotation speed. This adjusts the amount of regenerated liquid stored in the regenerated liquid space 50b to a predetermined amount.

[0103] In this way, the first return mechanism 57 adjusts the amount of the first phase portion stored in the regeneration-side reservoir 50 to be equal to or less than a predetermined amount, and the second return mechanism 60 adjusts the amount of the second phase portion stored in the regeneration-side reservoir 50 to be equal to or less than a predetermined amount. This allows the regeneration of the treatment liquid by the regenerator 14 to be completed.

[0104] In this embodiment, the treatment liquid introduced from the regenerator 14 to the regeneration-side reservoir 50 may include both regenerated treatment liquid and unregenerated treatment liquid (unregenerated liquid). In this case, in the regeneration-side reservoir 50, the regenerated treatment liquid flows into the regenerated liquid space 50b, while the unregenerated liquid is stored in the introduction liquid space 50a. The return mechanisms 57, 60 are then activated to return the unregenerated liquid to the regenerator 14. By operating the return mechanisms 57, 60, at least a portion of the unregenerated liquid is returned to the regenerator 14. Therefore, even if unregenerated treatment liquid is generated in the regenerator 14 and accumulates in the regeneration-side reservoir 50, this unregenerated treatment liquid is returned to the regenerator 14 and heated again. This promotes the regeneration process of the unregenerated treatment liquid. This prevents the treated liquid having a composition ratio different from that of the treated liquid initially charged from returning to the absorber 12, thereby preventing fluctuations in the ratio of the first component (first phase portion) to the second component (second phase portion) contained in the treated liquid circulating between the regenerator 14 and the absorber 12. This prevents imbalances in the first component (first phase portion) and the second component (second phase portion) between the absorber 12 and the regenerator 14.

[0105] In this embodiment, the pump 35 sends the regenerated treated liquid toward the absorber 12 so that the liquid level of the regenerated treated liquid accumulated in the regenerated liquid space 50b falls within a predetermined range. By controlling the liquid level in the regeneration-side reservoir 50 in this manner, it is possible to obtain circulation of the treated liquid between the absorber 12 and the regenerator 14 in such a way that imbalance between the first component (first phase portion) and the second component (second phase portion) is unlikely to occur, even without controlling the flow rate of the treated liquid sent from the absorber 12 to the regenerator 14.

[0106] Even when the liquid level is controlled in the regeneration-side reservoir 50, the absorption-side reservoir 26 may be provided. In this case, however, simplified control can be performed in the absorption-side reservoir 26.

[0107] Specifically, in the absorption-side reservoir 26, as shown in Fig. 21 or 22, a first detector 31 is provided in the inlet-side space 26a to detect whether the liquid-liquid interface between the first phase and the second phase is within a predetermined range. The first flow rate adjustment mechanism 28 is controlled based on the detection result of the first detector 31 so that the liquid-liquid interface between the first phase and the second phase is within the predetermined range. Fig. 21 shows a case where the first detector 31 is configured with a pair of level switches, and Fig. 22 shows a case where the first detector 31 is configured with a level sensor.

[0108] On the other hand, the second detector 32 for monitoring the liquid level of the second phase portion is omitted in the adjacent space 26b, so the flow rate controlled by the second flow rate control mechanism 29 for sending the second phase portion from the absorption-side reservoir 26 can be set arbitrarily by the user.

[0109] Although the description of other configurations, actions, and effects will be omitted, the descriptions of the first to fourth embodiments can be applied to the fifth embodiment.

[0110] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The present invention is not limited to the above-described embodiments, and various modifications and improvements are possible without departing from the spirit of the present invention.

[0111] Here, the above embodiment will be outlined.

[0112] (1) The gas treatment device according to the embodiment is a gas treatment device for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the gas treatment device comprising: an absorber that brings the gas to be treated and the treatment liquid into contact with each other to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; and a regenerator that separates the first phase portion and the second phase portion in the absorber. a first detector for detecting whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range; a second detector for detecting whether a liquid level of the second phase portion in the absorption-side reservoir is within a predetermined range; a first flow rate adjustment mechanism for adjusting a flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the first detector so that the liquid-liquid interface falls within the predetermined range; and a second flow rate adjustment mechanism for adjusting a flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the second detector so that the liquid level of the second phase portion falls within the predetermined range.

[0113] In the gas treatment device, when the treatment liquid absorbs the acidic compounds in the absorber, the treatment liquid undergoes phase separation into a first phase portion containing mainly the first component and a second phase portion containing mainly the second component. This phase-separated treatment liquid is stored in the absorption-side reservoir. In the absorption-side reservoir, the second phase portion containing mainly the second component with a lower specific gravity accumulates above the first phase portion containing mainly the first component, creating a liquid-liquid interface between the first and second phase portions. The first flow rate adjustment mechanism adjusts the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator so that this liquid-liquid interface falls within a predetermined range. The second flow rate adjustment mechanism adjusts the flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator so that the liquid level of the second phase portion falls within a predetermined range. Therefore, by utilizing the fact that the first phase portion and the second phase portion accumulate in layers in the absorption-side reservoir, the ratio of the first phase portion to the second phase portion accumulated in the absorption-side reservoir is adjusted within a predetermined range, thereby preventing imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator.

[0114] The first detector is not limited to a configuration that directly detects the position of the liquid-liquid interface between the first phase and the second phase. The first detector may be configured to detect whether the liquid-liquid interface is within a predetermined range by, for example, detecting that a predetermined amount of the first phase is accumulated using a pair of switches or sensors. Furthermore, the concept of the first flow rate adjustment mechanism and the second flow rate adjustment mechanism adjusting the flow rate so that the liquid-liquid interface or the liquid level is within a predetermined range also includes adjusting the flow rate so that the position of the liquid-liquid interface or the liquid level coincides with a target value.

[0115] (2) The absorption-side reservoir may have a partition member that divides the space within the reservoir into a first space into which the treatment liquid from the absorber is introduced and which stores the treatment liquid in a state of phase separation into a first phase portion and a second phase portion, and a second space into which the second phase portion overflowing from the first space is introduced. In this case, the first detector may be used to detect whether a liquid-liquid interface between the first phase portion and the second phase portion in the first space is within a predetermined range, and the second detector may be used to detect whether an amount of the second phase portion stored in the second space is within a predetermined range.

[0116] In this aspect, the absorption-side reservoir is divided by the partition member into a first space in which the phase-separated treatment liquid is stored and a second space in which only the second phase portion is stored. Therefore, the second flow rate control mechanism can prevent the first phase portion from being discharged, making it easy to adjust the flow rates using the first flow rate control mechanism and the second flow rate control mechanism.

[0117] (3) The first flow rate adjustment mechanism may be configured to increase the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is higher than the predetermined range, and to reduce the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is lower than the predetermined range. Furthermore, the second flow rate adjustment mechanism may be configured to increase the flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator when the detection result of the second detector indicates that the liquid level of the second phase portion is higher than the predetermined range, and to reduce the flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator when the detection result of the second detector indicates that the liquid level of the second phase portion is lower than the predetermined range.

[0118] In this embodiment, when the amount of the first phase fraction accumulated in the absorption-side reservoir is greater than a predetermined amount, the flow rate of the first phase fraction sent from the absorption-side reservoir to the regenerator is increased, and when the amount is less than the predetermined amount, the flow rate of the first phase fraction sent from the absorption-side reservoir to the regenerator is reduced. Furthermore, when the amount of the second phase fraction accumulated in the absorption-side reservoir is greater than a predetermined amount, the flow rate of the second phase fraction sent from the absorption-side reservoir to the regenerator is increased, and when the amount is less than the predetermined amount, the flow rate of the second phase fraction sent from the absorption-side reservoir to the regenerator is reduced. This further reduces the occurrence of imbalances in the distribution of the first component (first phase fraction) and the second component (second phase fraction) between the absorber and the regenerator.

[0119] The liquid-liquid interface between the first and second phases and the predetermined range of the liquid level of the second phase are controlled so that the ratio of the first component (first phase) to the second component (second phase) contained in the treatment liquid when introduced into the gas treatment device is maintained in both the absorber and the regenerator. Therefore, when the liquid-liquid interface between the first and second phases in the absorption-side reservoir becomes higher than the predetermined range, the flow rate of the first phase sent from the absorption-side reservoir to the regenerator can be increased, making it easier to maintain the initial ratio of the first component (first phase) to the second component (second phase) in both the absorber and the regenerator.

[0120] (4) The gas treatment device may further include a regeneration side reservoir into which the treatment liquid heated in the regenerator is introduced, the regeneration side reservoir having an introduction liquid space in which the introduced treatment liquid is stored, and a regeneration liquid space that receives regenerated treatment liquid from the introduction liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; and an unregenerated liquid return mechanism that returns the unregenerated treatment liquid that accumulates in the introduction liquid space to the regenerator when the treatment liquid contains unregenerated treatment liquid.

[0121] The treatment liquid introduced from the regenerator to the regeneration-side reservoir may contain unregenerated treatment liquid (unregenerated liquid). In this case, an unregenerated liquid return mechanism is activated to return the unregenerated liquid from the regeneration-side reservoir to the regenerator. That is, the unregenerated liquid in the regeneration-side reservoir can be returned to the regenerator without being returned to the absorber, while the regenerated treatment liquid can be returned to the absorber from the regenerated liquid space. Therefore, even if unregenerated treatment liquid is generated in the regenerator and accumulates in the regeneration-side reservoir, this unregenerated treatment liquid is returned to the regenerator and heated again, thereby accelerating the regeneration of the unregenerated treatment liquid. This prevents treatment liquid with a composition ratio different from that of the treatment liquid initially charged from returning to the absorber. This prevents fluctuations in the ratio of the first component (first phase portion) to the second component (second phase portion) contained in the treatment liquid circulating between the regenerator and the absorber. Therefore, it is possible to further prevent imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator. Moreover, the regenerated treated liquid, which is introduced into the liquid introduction space of the regeneration-side reservoir, flows into the regenerated liquid space, so that it is possible to prevent the regenerated treated liquid from being returned from the liquid introduction space to the regenerator.

[0122] (5) The gas treatment device according to the above embodiment is a gas treatment device for releasing the acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, and includes an absorber that brings the gas to be treated and the treatment liquid into contact with each other, and absorbs the acidic compounds contained in the gas to be treated into the treatment liquid. a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; a regeneration side reservoir into which the treatment liquid heated in the regenerator is introduced, the regeneration side reservoir having an introduction liquid space in which the introduced treatment liquid is stored and a regeneration liquid space that receives regenerated treatment liquid from the introduction liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; and an unregenerated liquid return mechanism that returns the unregenerated treatment liquid that accumulates in the introduction liquid space to the regenerator when the treatment liquid contains unregenerated treatment liquid.

[0123] In the gas treatment device, when the treated liquid is heated in the regenerator, the treated liquid releases acidic compounds. As a result, at least a portion of the treated liquid that had been phase-separated into a first phase and a second phase returns to a non-phase-separated state. The treated liquid introduced from the regenerator to the regeneration-side reservoir may contain unregenerated treated liquid (unregenerated liquid). In this case, in the regeneration-side reservoir, the regenerated treated liquid flows from the liquid introduction space into the regenerated liquid space, while the unregenerated liquid is stored in the liquid introduction space. An unregenerated liquid return mechanism is then activated to return the unregenerated liquid to the regenerator. That is, the unregenerated liquid in the regeneration-side reservoir can be returned to the regenerator without being returned to the absorber, while the regenerated treated liquid can be returned from the regenerated liquid space to the absorber. Therefore, even if unregenerated treated liquid is generated in the regenerator and accumulates in the regeneration-side reservoir, this unregenerated treated liquid is returned to the regenerator and heated again, thereby accelerating the regeneration of the unregenerated treated liquid. This prevents the treated liquid having a composition ratio different from that of the initially charged treated liquid from returning to the absorber, thereby preventing fluctuations in the ratio of the first component (first phase portion) to the second component (second phase portion) contained in the treated liquid circulating between the regenerator and the absorber. Therefore, it is possible to prevent imbalances in the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator. Furthermore, the regenerated treated liquid introduced into the liquid introduction space of the regeneration-side reservoir flows into the regenerated liquid space, preventing the regenerated treated liquid from returning from the liquid introduction space to the regenerator.

[0124] (6) The unregenerated liquid return mechanism may include a first return mechanism for returning the first phase portion of the treatment liquid accumulating in the introduction liquid space to the regenerator so that the amount of the first phase portion accumulated in the introduction liquid space is equal to or less than a predetermined amount, and a second return mechanism for returning the second phase portion of the treatment liquid in the introduction liquid space to the regenerator so that the liquid level of the treatment liquid accumulating in the introduction liquid space is equal to or less than a predetermined amount.

[0125] In this aspect, when unregenerated treated liquid (unregenerated liquid) is generated, the unregenerated liquid accumulates in the liquid introduction space. The first phase portion of the unregenerated liquid accumulated in the liquid introduction space is returned to the regenerator by the first return mechanism, and the second phase portion is returned to the regenerator by the second return mechanism. At this time, the second return mechanism causes the second phase portion to flow out so that the liquid level of the treated liquid accumulated in the liquid introduction space is below a predetermined level. The first return mechanism also causes the first phase portion to flow out so that the amount of the first phase portion of the treated liquid accumulated in the liquid introduction space is below a predetermined level. This promotes the regeneration of the unregenerated liquid, further suppressing fluctuations in the ratio of the first component (first phase portion) to the second component (second phase portion) contained in the treated liquid circulating between the regenerator and the absorber.

[0126] (7) The gas treatment device may include a first unregenerated liquid detector for detecting whether a first phase portion of the unregenerated treatment liquid has accumulated to a predetermined amount or more. In this case, the first return mechanism may return the first phase portion to the regenerator when the first unregenerated liquid detector detects that the first phase portion has accumulated to a predetermined amount or more.

[0127] In this embodiment, when it is detected that a predetermined amount or more of the first phase portion has accumulated in the introduction liquid space, the unregenerated first phase portion is returned to the regenerator, thereby preventing the unregenerated first phase portion from accumulating in the regeneration-side reservoir.

[0128] (8) The gas treatment device may include an absorption-side reservoir that stores the treatment liquid that has been phase-separated into the first phase portion and the second phase portion in the absorber; a first flow rate control mechanism that sends the first phase portion from the absorption-side reservoir to the regenerator; a second flow rate control mechanism that sends the second phase portion from the absorption-side reservoir to the regenerator; and a regenerated liquid flow rate control mechanism that sends the regenerated treatment liquid from the regeneration-side reservoir to the absorber so that a predetermined amount of the regenerated treatment liquid is accumulated in the regeneration-side reservoir.

[0129] In this embodiment, the regeneration-side reservoir is adjusted so that a predetermined amount of regenerated treated liquid is accumulated therein. In this case, the flow rates of the first and second phase portions sent from the absorption-side reservoir to the regenerator by the first and second flow rate adjustment mechanisms are determined according to the flow rate of the regenerated liquid sent from the regeneration-side reservoir to the absorber by the regenerated liquid flow rate adjustment mechanism. In other words, by adjusting the amount of regenerated treated liquid stored in the regeneration-side reservoir by the regenerated liquid flow rate adjustment mechanism, it is possible to prevent imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator.

[0130] (9) The regeneration-side reservoir may include a partition member that separates the regenerated treatment liquid into an introduction liquid space into which the treatment liquid is introduced from the regenerator and a regenerated treatment liquid space into which the regenerated treatment liquid from the introduction liquid space flows in. In this case, the regenerated liquid flow rate adjustment mechanism may include a detector that detects the liquid level of the regenerated treatment liquid in the regenerated liquid space, and a pump that sends the regenerated treatment liquid in the regenerated liquid space to the absorber so that the liquid level falls within a predetermined range based on the detection result by the detector.

[0131] In this embodiment, the pump sends the regenerated treated liquid toward the absorber so that the liquid level of the regenerated treated liquid accumulated in the regenerator space is within a predetermined range. By controlling the liquid level in the regenerator-side reservoir in this manner, circulation of the treated liquid is achieved that is less likely to cause imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator. In this case, the flow rate of the treated liquid sent from the absorber to the regenerator can be determined as desired, so no special flow rate control is required on the absorber side.

[0132] (10) The gas treatment device may include a first detector for detecting whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range. In this case, the first flow rate adjustment mechanism may be configured to adjust the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the first detector so that the liquid-liquid interface is within the predetermined range.

[0133] In this aspect, the liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is adjusted to fall within a predetermined range based on the detection result by the first detector. Therefore, in combination with the control of the storage amount of the regenerated treatment liquid in the regeneration-side reservoir, it is possible to further suppress the imbalance between the first component (first phase portion) and the second component (second phase portion) between the absorber and the regenerator.

[0134] (11) A gas treatment method according to the above embodiment is a gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, wherein the gas to be treated and the treatment liquid are brought into contact with each other in an absorber to absorb the acidic compounds contained in the gas to be treated into the treatment liquid, and the treatment liquid that has been phase-separated into the first phase portion and the second phase portion in the absorber is stored in an absorption-side reservoir, and the absorption liquid is separated into the first phase portion and the second phase portion in the absorber. The treated liquid sent from the absorption-side reservoir is heated in a regenerator to separate acidic compounds from the treated liquid, a first detector is used to detect whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range, a second detector is used to detect whether a liquid level of the second phase portion in the absorption-side reservoir is within a predetermined range, and based on the detection result by the first detector, the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator is adjusted so that the liquid-liquid interface falls within the predetermined range, and based on the detection result by the second detector, the flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator is adjusted so that the liquid level of the second phase portion falls within the predetermined range.

[0135] (12) The space within the absorption-side reservoir may be partitioned into a first space into which the treatment liquid is introduced from the absorber and which stores the treatment liquid in a state of phase separation into a first phase portion and a second phase portion, and a second space into which the second phase portion overflowing from the first space is introduced. In this case, in the gas treatment method, the first detector may detect whether a liquid-liquid interface between the first phase portion and the second phase portion in the first space is within a predetermined range, and the second detector may detect whether an amount of the second phase portion stored in the second space is within a predetermined range.

[0136] (13) In the gas treatment method, when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is higher than the predetermined range, a flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator may be increased; when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is lower than the predetermined range, a flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator may be reduced; when the detection result of the second detector indicates that the liquid level of the second phase portion is higher than the predetermined range, a flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator may be increased; and when the detection result of the second detector indicates that the liquid level of the second phase portion is lower than the predetermined range, a flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator may be reduced.

[0137] (14) In the gas treatment method, the treatment liquid heated in the regenerator may be introduced into a regeneration side reservoir, and the introduced treatment liquid may be stored in an introduction liquid space in the regeneration side reservoir. Even if the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid, the regenerated treatment liquid may be caused to flow from the introduction liquid space into the regeneration liquid space. If the treatment liquid contains unregenerated treatment liquid, the unregenerated treatment liquid that accumulates in the introduction liquid space may be returned to the regenerator.

[0138] (15) A gas treatment method according to the above embodiment is a gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate an acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a specific gravity smaller than that of the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, and in which the gas to be treated and the treatment liquid are brought into contact with each other in an absorber to release the acidic compounds contained in the gas to be treated. The acidic compounds are absorbed into the treatment liquid, the treatment liquid sent from the absorber is heated in a regenerator to separate the acidic compounds from the treatment liquid, the treatment liquid heated in the regenerator is introduced into a regeneration side reservoir, the introduced treatment liquid is stored in an introduction liquid space in the regeneration side reservoir, and even if the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid, the regenerated treatment liquid is allowed to flow from the introduction liquid space into the regeneration liquid space, and if the treatment liquid contains unregenerated treatment liquid, the unregenerated treatment liquid that has accumulated in the introduction liquid space is returned to the regenerator.

[0139] (16) In the gas treatment method, the first phase portion of the treatment liquid accumulating in the introduction liquid space may be returned to the regenerator so that the amount of the first phase portion accumulated in the introduction liquid space is equal to or less than a predetermined amount, and the second phase portion of the treatment liquid in the introduction liquid space may be returned to the regenerator so that the liquid level of the treatment liquid accumulating in the introduction liquid space is equal to or less than a predetermined amount.

[0140] (17) In the gas treatment method, a first unregenerated liquid detector may detect whether a first phase portion of the unregenerated treatment liquid has accumulated in a predetermined amount or more, and when the first unregenerated liquid detector detects that a first phase portion of the unregenerated treatment liquid has accumulated in a predetermined amount or more, the first phase portion may be returned to the regenerator.

[0141] (18) In the gas treatment method, the treated liquid that has been phase-separated into the first phase portion and the second phase portion in the absorber may be stored in an absorption-side reservoir, the first phase portion and the second phase portion may be sent from the absorption-side reservoir to the regenerator, and the regenerated treated liquid may be sent from the regeneration-side reservoir to the absorber so that a predetermined amount of the regenerated treated liquid is stored in the regeneration-side reservoir.

[0142] (19) The space within the regeneration-side reservoir may be partitioned into an introduction liquid space into which the treatment liquid is introduced from the regenerator, and a regeneration liquid space into which the regenerated treatment liquid from the treatment liquid in the introduction liquid space flows in. In this case, in the gas treatment method, a detector may be used to detect the liquid level of the regenerated treatment liquid in the regeneration liquid space, and based on the detection result by the detector, the regenerated treatment liquid in the regeneration liquid space may be sent to the absorber so that the liquid level falls within a predetermined range.

[0143] (20) In the gas treatment method, a first detector may be used in the absorption-side reservoir to detect whether a liquid-liquid interface between the first phase portion and the second phase portion is within a predetermined range, and the flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator may be adjusted based on the detection result by the first detector so that the liquid-liquid interface is within the predetermined range.

[0144] As described above, it is possible to prevent the liquid composition from becoming unbalanced in the absorber and the regenerator.

[0145] This application is based on Japanese Patent Application No. 2023-172116 filed with the Japan Patent Office on October 3, 2023, the contents of which are incorporated herein by reference.

[0146] In order to express the present invention, the present invention has been properly and sufficiently described above through the embodiments with reference to the drawings, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims.

Claims

1. A gas treatment device for releasing acidic compounds from a gas to be treated that contains acidic compounds that produce acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a smaller specific gravity than the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the device comprising: an absorber that brings the gas to be treated and the treatment liquid into contact with each other to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; an absorption-side reservoir that stores the treatment liquid that has been phase-separated into the first phase portion and the second phase portion in the absorber; and a first detector that detects whether the liquid-liquid interface between the first phase portion and the second phase portion in the absorption-side reservoir is within a predetermined range. a second detector for detecting whether a liquid level of the second phase portion is within a predetermined range in the absorption-side reservoir; a first flow rate adjustment mechanism for adjusting a flow rate of the first phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the first detector so that the liquid-liquid interface falls within the predetermined range; and a second flow rate adjustment mechanism for adjusting a flow rate of the second phase portion sent from the absorption-side reservoir to the regenerator based on a detection result by the second detector so that the liquid level of the second phase portion falls within the predetermined range.

2. The gas treatment device according to claim 1, wherein the absorption side reservoir has a partition member dividing the space within the reservoir into a first space into which the treatment liquid is introduced from the absorber and which stores the treatment liquid in a state of phase separation into a first phase portion and a second phase portion, and a second space into which the second phase portion overflowing from the first space is introduced, the first detector is used to detect whether the liquid-liquid interface between the first phase portion and the second phase portion in the first space is within a predetermined range, and the second detector is used to detect whether the amount of the second phase portion stored in the second space is within a predetermined range.

3. The gas treatment device according to claim 1 or 2, wherein the first flow rate adjustment mechanism is configured to: increase the flow rate of the first phase portion sent from the absorption side reservoir to the regenerator when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is higher than the specified range; and reduce the flow rate of the first phase portion sent from the absorption side reservoir to the regenerator when the detection result of the first detector indicates that the liquid-liquid interface between the first phase portion and the second phase portion is lower than the specified range; and the second flow rate adjustment mechanism is configured to: increase the flow rate of the second phase portion sent from the absorption side reservoir to the regenerator when the detection result of the second detector indicates that the liquid level of the second phase portion is higher than the specified range; and reduce the flow rate of the second phase portion sent from the absorption side reservoir to the regenerator when the detection result of the second detector indicates that the liquid level of the second phase portion is lower than the specified range.

4. A gas treatment device as described in claim 1 or 2, further comprising: a regeneration side reservoir into which the heated treatment liquid in the regenerator is introduced, the regeneration side reservoir having an introduction liquid space in which the introduced treatment liquid is stored, and a regeneration liquid space for receiving regenerated treatment liquid from the introduction liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; and an unregenerated liquid return mechanism for returning the unregenerated treatment liquid accumulated in the introduction liquid space to the regenerator when the treatment liquid contains unregenerated treatment liquid.

5. A gas treatment device for releasing acidic compounds from a gas to be treated that contains acidic compounds that produce acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a smaller specific gravity than the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the device comprising: an absorber that brings the gas to be treated and the treatment liquid into contact with each other to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; a regenerator that heats the treatment liquid that has absorbed the acidic compounds to separate the acidic compounds from the treatment liquid; and a regeneration-side reservoir into which the treatment liquid heated in the regenerator is introduced, the regeneration-side reservoir having an introduction liquid space in which the introduced treatment liquid is stored, and a regeneration liquid space that receives regenerated treatment liquid from the introduction liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; and an unregenerated liquid returning mechanism that returns the unregenerated treatment liquid accumulated in the liquid introduction space to the regenerator when the unregenerated treatment liquid is contained in the treatment liquid.

6. The gas treatment device described in claim 5, wherein the unregenerated liquid return mechanism includes a first return mechanism for returning the first phase portion of the treatment liquid accumulating in the introduction liquid space to the regenerator so that the amount of the first phase portion is equal to or less than a predetermined amount, and a second return mechanism for returning the second phase portion of the treatment liquid in the introduction liquid space to the regenerator so that the liquid level of the treatment liquid accumulating in the introduction liquid space is equal to or less than a predetermined amount.

7. A gas treatment device as described in claim 6, further comprising a first unregenerated liquid detector for detecting whether a first phase portion of the unregenerated treatment liquid has accumulated in a predetermined amount or more, and the first return mechanism returns the first phase portion to the regenerator when the first unregenerated liquid detector detects that a first phase portion of the unregenerated treatment liquid has accumulated in a predetermined amount or more.

8. A gas treatment device as described in claim 5, comprising: an absorption-side reservoir for storing the treated liquid that has been phase-separated into the first phase and the second phase in the absorber; a first flow rate control mechanism for sending the first phase from the absorption-side reservoir to the regenerator; a second flow rate control mechanism for sending the second phase from the absorption-side reservoir to the regenerator; and a regenerated liquid flow rate control mechanism for sending the regenerated treated liquid from the regeneration-side reservoir to the absorber so that a predetermined amount of the regenerated treated liquid is accumulated in the regeneration-side reservoir.

9. A gas treatment device as described in claim 8, wherein the regeneration side reservoir is provided with a partition member dividing an introduction liquid space into which the treatment liquid is introduced from the regenerator and a regenerated liquid space into which regenerated treatment liquid from the treatment liquid in the introduction liquid space flows, and the regenerated liquid flow rate control mechanism is provided with a detector for detecting the liquid level of the regenerated treatment liquid in the regenerated liquid space, and a pump for sending the regenerated treatment liquid in the regenerated liquid space to the absorber so that the liquid level falls within a predetermined range based on the detection result by the detector.

10. A gas treatment device as described in claim 8 or 9, further comprising a first detector for detecting whether a liquid-liquid interface between the first phase portion and the second phase portion in the absorption side reservoir is within a predetermined range, and the first flow rate control mechanism is configured to adjust the flow rate of the first phase portion sent from the absorption side reservoir to the regenerator based on the detection result by the first detector so that the liquid-liquid interface is within the predetermined range.

11. A gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that produce acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a smaller specific gravity than the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the method comprising the steps of: bringing the gas to be treated and the treatment liquid into contact with each other in an absorber to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; storing the treatment liquid in the absorber that has been phase-separated into the first phase portion and the second phase portion; heating the treatment liquid sent from the absorption side reservoir in a regenerator to separate the acidic compounds from the treatment liquid; using a first detector to detect whether the liquid-liquid interface between the first phase portion and the second phase portion in the absorption side reservoir is within a predetermined range; a second detector is used to detect whether the liquid level of the second phase portion in the absorption side reservoir is within a predetermined range; based on a detection result by the first detector, a flow rate of the first phase portion sent from the absorption side reservoir to the regenerator is adjusted so that the liquid-liquid interface falls within a predetermined range; and based on a detection result by the second detector, a flow rate of the second phase portion sent from the absorption side reservoir to the regenerator is adjusted so that the liquid level of the second phase portion falls within a predetermined range.

12. A gas treatment method for releasing acidic compounds from a gas to be treated that contains acidic compounds that generate acid when dissolved in water, using a treatment liquid that is in a mixed state of a first component and a second component having a smaller specific gravity than the first component before absorbing the acidic compounds, and that undergoes phase separation into a first phase portion mainly containing the first component and a second phase portion mainly containing the second component upon absorption of the acidic compounds, the method comprising the steps of: in an absorber, bringing the gas to be treated and the treatment liquid into contact with each other to absorb the acidic compounds contained in the gas to be treated into the treatment liquid; heating the treatment liquid sent from the absorber in a regenerator to separate the acidic compounds from the treatment liquid; introducing the heated treatment liquid in the regenerator into a regeneration-side reservoir; storing the introduced treatment liquid in an introduction liquid space in the regeneration-side reservoir; and allowing regenerated treatment liquid to flow from the introduction liquid space into the regeneration liquid space even when the treatment liquid introduced into the introduction liquid space contains unregenerated treatment liquid; When the treatment liquid contains an unregenerated treatment liquid, the unregenerated treatment liquid accumulated in the liquid introduction space is returned to the regenerator.

Images