JP2018202274A - Carbon dioxide recovery system and carbon dioxide recovery method - Google Patents

Abstract

To efficiently supply and use a diffusion inhibiting liquid for recovering an absorbent from gas discharged from an absorption part.SOLUTION: A carbon dioxide recovery system includes an absorption part which makes an absorbent absorb carbon dioxide in combustion exhaust gas, a regeneration part which emits the carbon dioxide from the absorption liquid with the carbon dioxide absorbed, a diffusion inhibiting part which recovers the absorbent accompanied by absorption part discharging gas discharged from the absorption part by a diffusion inhibiting liquid. The system further includes a diffusion inhibiting liquid holding part which supplies the diffusion inhibiting liquid to the diffusion inhibiting part, recovers the diffusion inhibiting liquid from the diffusion inhibiting part, and discharges the diffusion inhibiting liquid as a waste liquid. The system includes a waste liquid separation part which has a waste liquid separation membrane for separating impurities derived from the absorbent from the waste liquid, and supplies a produced liquid, as the waste liquid with the impurities reduced by the waste liquid separation membrane, as the diffusion inhibiting liquid.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a carbon dioxide recovery system and a carbon dioxide recovery method.

  In recent years, the carbon dioxide component in exhaust gas (combustion exhaust gas) discharged from combustion systems such as thermal power plants has been a cause of global warming. Recovery is required. As a wet recovery method for recovering the carbon dioxide component in the exhaust gas in a wet manner, a chemical absorption method using an absorption liquid similar to an alkanolamine aqueous solution is widely known.

  A carbon dioxide recovery system that employs such a chemical absorption method generally includes an absorption unit and a regeneration unit. In the absorption part, the exhaust gas and the absorption liquid are brought into contact with each other, whereby carbon dioxide in the exhaust gas is dissolved in the absorption liquid, and carbon dioxide is removed from the exhaust gas. The absorption liquid (rich liquid) that has absorbed carbon dioxide is discharged from the absorption section, and releases high-concentration carbon dioxide by a heating regeneration operation in the regeneration section. The absorption liquid (lean liquid) from which carbon dioxide has been released is sent from the regeneration section to the absorption section as a regenerated absorption liquid that can absorb carbon dioxide again. In this way, the absorption liquid circulates between the absorption part and the regeneration part and is reused repeatedly.

  Here, it is known that when the exhaust gas comes into contact with the absorption liquid in the absorption section, carbon dioxide in the exhaust gas is absorbed by the absorption liquid, and part of the absorption liquid is released from the absorption section along with the exhaust gas. Yes. In order to prevent the absorption liquid component accompanying the exhaust gas from being diffused into the atmosphere, an exhaust gas cleaning section (a diffusion suppression section) for cleaning the exhaust gas with the cleaning water is disposed after the absorption section, and the absorption liquid component is carbon dioxide. It is conceivable to suppress leakage from the collection system. The cleaning water from which the absorbent component is recovered from the exhaust gas is reused as cleaning water or discarded as waste water.

  It is also known that high-concentration carbon dioxide gas released from the regeneration unit is accompanied by an absorbent component. Due to the cooling of the carbon dioxide gas or the like, the water vapor released together with the carbon dioxide gas is condensed, and condensed water containing the absorption liquid component is generated as waste water.

  Thus, waste water as washing water or condensed water is generated in the exhaust gas cleaning section and the regeneration section. On the other hand, in the carbon dioxide recovery system, replenishing water for replenishing cleaning water used in the exhaust gas cleaning unit is required. Therefore, a technique is known in which the waste water containing the absorbing liquid is evaporated and then condensed to generate condensed water, and this condensed water is reused as makeup water. Hereinafter, this condensed water is referred to as reused condensed water.

Japanese Patent No. 5371734 Japanese Patent No. 5351728

  When the above-mentioned reused condensed water is generated, there is a possibility that thermal deterioration or heat oxidation of the absorption liquid component may occur due to thermal operation during evaporation. In this case, a volatile organic component is generated from the absorbing liquid component, which may be mixed into the reused condensed water. When such reused condensed water is reused as makeup water, volatile organic components may be released into the environment.

  Further, when the water quality of the makeup water is made acidic and used in the emission suppressing unit, it becomes a problem to consume the acidic chemical solution for adjusting the quality of the makeup water.

  Therefore, embodiments of the present invention provide a carbon dioxide recovery system and a carbon dioxide recovery method capable of efficiently supplying and using a diffusion suppression liquid for recovering an absorption liquid from a gas discharged from an absorption section. The task is to do.

  According to one embodiment, a carbon dioxide recovery system includes an absorption unit that absorbs carbon dioxide in combustion exhaust gas into an absorption liquid, a regeneration unit that releases the carbon dioxide from the absorption liquid that has absorbed the carbon dioxide, A diffusion suppression unit that recovers the absorption liquid accompanying the absorption unit exhaust gas discharged from the absorption unit with a diffusion suppression liquid. The system further includes a emission suppression liquid holding unit that supplies the emission suppression liquid to the emission suppression unit, collects the emission suppression liquid from the emission suppression unit, and discharges the emission suppression liquid as drainage. The system further includes a drainage separation membrane that separates impurities derived from the absorption liquid from the drainage liquid, and the production liquid that is the drainage liquid in which the impurities are reduced by the drainage separation film is suppressed from being emitted. A drain separation unit that supplies the liquid is provided.

  According to the embodiment of the present invention, it is possible to efficiently use the emission suppressing liquid.

It is a mimetic diagram showing the composition of the carbon dioxide recovery system of a 1st embodiment. It is a schematic diagram which shows the structure of the carbon dioxide collection system of 2nd Embodiment. It is a schematic diagram which shows the structure of the carbon dioxide collection system of 3rd Embodiment. It is a schematic diagram which shows the structure of the carbon dioxide collection system of 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, the same or similar components are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
Drawing 1 is a mimetic diagram showing the composition of the carbon dioxide recovery system of a 1st embodiment.

  The carbon dioxide recovery system of the present embodiment includes an absorption unit 11, a diffusion suppression unit 12, a rich liquid flow path 13, a heat exchanger 14, a regeneration unit 15, a regeneration unit heater 16, and a gas purification unit 17. An example of the lean liquid flow path 18, the makeup water supply unit 21, a diffusion suppression water storage tank 22 that is an example of a diffusion suppression liquid holding unit, a first valve 23, a second valve 24, and a drainage filtration unit. The waste water filtration part 25, the sterilization part 26, the waste water separation part 27 which is an example of the drainage separation part, and the heating purification part 28 are provided. The drainage separation unit 27 includes a drainage separation membrane 27a that is an example of a drainage separation membrane, an inlet portion 27b, a first outlet portion 27c, and a second outlet portion 27d.

  The absorber 11 removes carbon dioxide in the combustion exhaust gas 1 supplied from a combustion system such as a thermal power plant by a chemical absorption method. Specifically, the absorption unit 11 makes the absorption liquid absorb the carbon dioxide in the combustion exhaust gas 1 by bringing the combustion exhaust gas 1 into contact with the absorption liquid, and removes the carbon dioxide from the combustion exhaust gas 1. As a result, the combustion exhaust gas 1 from which carbon dioxide has been removed is discharged from the absorption unit 11 as the absorption unit exhaust gas 2. Specific examples of the combustion exhaust gas 1 and the absorbing liquid will be described later.

  Since the absorption part exhaust gas 2 accompanies the absorption liquid component, the absorption part exhaust gas 2 is introduced into the emission suppressing part 12 arranged at the subsequent stage of the absorption part 11. The emission suppression unit 12 recovers the absorption liquid component accompanying the absorption unit exhaust gas 2 with the emission suppression water by washing the absorption unit exhaust gas 2 with the emission suppression water (washing water). The absorber exhaust gas 2 is washed by gas-liquid contact between the absorber exhaust gas 2 and the emission suppression water. As a result, the absorption section exhaust gas 2 from which the absorption liquid component has been removed is discharged from the emission suppressing section 12 as the processed gas 3. The emission suppression water may be replaced with a liquid other than water.

  On the other hand, the absorption unit 11 discharges the absorption liquid (rich liquid) that has absorbed carbon dioxide to the rich liquid flow path 13. This absorption liquid is supplied to the regeneration unit 15 via the heat exchanger 14 on the rich liquid flow path 13.

  In the regeneration unit 15, the absorption liquid is heated by the regeneration unit heater 16 to generate water vapor or carbon dioxide gas, and the water vapor or carbon dioxide gas is returned to the regeneration unit 15, and the regeneration unit 15 is heated by the heat of water vapor or carbon dioxide. The absorption liquid inside is heated. As a result, carbon dioxide gas and water vapor are released from the absorption liquid in the regeneration unit 15, and these carbon dioxide gas and water vapor are discharged from the regeneration unit 15 as the regeneration unit exhaust gas 4.

  Since the regeneration unit exhaust gas 4 is accompanied by an absorption liquid component, the regeneration unit exhaust gas 4 is introduced into the gas purification unit 17 disposed at the subsequent stage of the regeneration unit 15. The gas purification unit 17 cools the regeneration unit exhaust gas 4 to condense the water vapor in the regeneration unit exhaust gas 4, thereby removing the absorbent component from the regeneration unit exhaust gas 4. As a result, the regeneration section exhaust gas 4 from which water vapor and absorption liquid components have been removed is discharged from the gas purification section 17 as recovered carbon dioxide gas 5. Further, the condensed water containing the absorption liquid component is discharged from the gas purification unit 17 as the purification unit waste water 6.

  On the other hand, the regeneration unit 15 discharges the absorption liquid (lean liquid) from which carbon dioxide has been released to the lean liquid flow path 18. This absorption liquid is supplied to the absorption unit 11 via the heat exchanger 14 on the lean liquid flow path 18. In the heat exchanger 14, the rich liquid that flows from the absorption unit 11 to the regeneration unit 15 is heated by the heat of the lean liquid that flows from the regeneration unit 15 to the absorption unit 11.

  Further, the above-described emission suppression water is supplied to the emission suppression unit 12 from the makeup water supply unit 21 or the emission suppression water storage tank 22 as indicated by reference numeral 7. The makeup water supply unit 21 supplies makeup water, which is clean water, to the emission suppression unit 12 as emission suppression water. On the other hand, the emission suppression water storage tank 22 is a tank for storing the emission suppression water discharged from the emission suppression unit 12 as indicated by reference numeral 8, and the water stored in the emission suppression water storage tank 22 is diffused as emission suppression water. Supply to the suppression unit 12. The emission suppression water discharged from the emission suppression unit 12 contains the absorption liquid component recovered by the emission suppression unit 12. All of the emission suppression water supplied from the makeup water supply unit 21 and the emission suppression water storage tank 22 to the emission suppression part 12 is collected in the emission suppression water storage tank 22.

  The first valve 23 is provided in the flow path from the diffusion suppression water storage tank 22 toward the diffusion suppression unit 12. When supplying the emission suppression water only from the makeup water supply unit 21, the first valve 23 is closed. The first valve 23 is opened when the diffusion suppression water is supplied only from the diffusion suppression water storage tank 22 or when the diffusion suppression water is supplied from the makeup water supply unit 21 and the diffusion suppression water storage tank 22.

  The 2nd valve | bulb 24 is provided in the flow path which discharges | emits the diffusion suppression water in the diffusion suppression water storage tank 22 as waste_water | drain. When the second valve 24 is opened, the diffusion suppression water in the diffusion suppression water storage tank 22 is supplied to the drainage filtration unit 25 as drainage.

  After passing through the drainage filtration unit 25 and the sterilization unit 26, the drainage is supplied to the inlet 27b of the drainage separation unit 27 as the water to be treated by the drainage separation membrane 27a. The product water discharged from the first outlet portion 27c of the drainage separation section 27 is sent to the diffusion suppression water storage tank 22 and the like, and the concentrated water discharged from the second outlet portion 27d of the drainage separation section 27 is sent to the heating and purification section 28. It is done. Details of the drainage filtration unit 25, the sterilization unit 26, the drainage separation unit 27, and the heat purification unit 28 will be described later.

  Next, the details of the carbon dioxide recovery system of this embodiment will be described.

  As described above, the absorption unit 11 removes carbon dioxide from the combustion exhaust gas 1 by causing the absorption liquid (chemical absorption liquid) to absorb carbon dioxide in the combustion exhaust gas 1. Examples of the combustion exhaust gas 1 are fossil fuel gas, garbage incineration gas, sludge incineration gas, and the like. Examples of the absorbing liquid are amine absorbing liquids applicable to carbon dioxide recovery, such as alkanolamines, cyclic amines, and diamines. The component of the absorption liquid can be selected from components with excellent chemical stability, carbon dioxide recovery ability, regeneration ability, and economic efficiency. If necessary, a mixed liquid (aqueous solution) containing multiple components can be selected as the absorption liquid. It can also be used. A known technique can be used for the contact treatment method between the absorption liquid and the combustion exhaust gas 1 in the absorption unit 11.

  The absorption part exhaust gas (decarbon dioxide gas) 2 is supplied to the emission suppressing part 12, and the absorption liquid component accompanying the absorption part exhaust gas 2 is removed by the emission suppression water. The emission suppression water that has absorbed the absorption liquid component is collected in the emission suppression water storage tank 22. In addition, according to the property and generation | occurrence | production amount of the dispersion | distribution suppression water collect | recovered, you may comprise the dispersion | distribution suppression water storage tank 22 as a division tank, and the means for adjusting the supply amount of makeup water is provided in a carbon dioxide recovery system. Also good. The diffusion suppression water in the diffusion suppression water storage tank 22 is discharged as drainage through the second valve 24 and introduced into the drainage filtration unit 25.

  The drainage filtration unit 25 removes solid matter in the wastewater by filtration, and discharges the wastewater from which the solid matter has been removed to the sterilization unit 26. The drainage filtration unit 25 can be configured by a known filtration technique capable of removing solids contained in wastewater, but can remove solid classification derived from microorganisms generated in wastewater containing BOD (Biochemical Oxygen Demand) components. It is desirable to configure as follows. For example, the drainage filtration unit 25 is configured with an MF (microfiltration) membrane and a UF (ultrafiltration) membrane, configured to perform a series multi-stage process of different types of membranes, or performs parallel processing of the same membrane. It is desirable to configure. Moreover, it is desirable that the drainage filtration unit 25 includes a measuring device and a control device for confirming the operation state of the drainage filtration unit 25, a chemical solution supply device for washing the filtration membrane, a backwashing mechanism, and the like.

  The sterilization unit 26 sterilizes the wastewater from the drainage filtration unit 25 and supplies the sterilized wastewater to the drainage separation unit 27. The sterilization unit 26 is provided in order to suppress the growth of microorganisms in the drainage separation unit 27. Since the waste water in the sterilization unit 26 is supplied from the drainage filtration unit 25, it is possible to suppress the solid classification derived from microorganisms from reducing the sterilization effect of the sterilization unit 26. The sterilization unit 26 can be configured by a known technique such as an ultraviolet irradiation device or a pasteurization method.

  The drainage separation unit 27 has a drainage separation membrane 27a that separates impurities derived from the absorption liquid from wastewater (treated water). Examples of impurities derived from the absorbing liquid are absorbing liquid components such as alkanolamines and chemical substances generated from the absorbing liquid components. Since the drainage separation unit 27 separates impurities not by heating the wastewater but by membrane treatment of the wastewater, it is possible to suppress thermal deterioration, thermal oxidation, decomposition, alteration, and the like of the absorption liquid component.

  Waste water from the sterilization unit 26 is introduced into the drain separation unit 27 from the inlet 27b as treated water and supplied to the drain separation membrane 27a. When the treated water passes through the wastewater separation membrane 27a, most of the impurities in the treated water cannot pass through the wastewater separation membrane 27a or are adsorbed by the wastewater separation membrane 27a. In the wastewater separation unit 27, a part of the water to be treated passes through the wastewater separation unit 27 to become production water in which impurities are reduced as compared to the water to be treated, and the production water is discharged from the first outlet portion 27c. The remaining part of the water to be treated does not pass through the waste water separation part 27, becomes concentrated water in which impurities are concentrated more than the water to be treated, and the concentrated water is discharged from the second outlet part 27d.

  Regarding the impurities derived from the absorbing liquid, the impurity concentration in the production water is lower than the impurity concentration in the water to be treated. Therefore, since the production water is suitable for use again as the emission suppression water, it is sent from the first outlet portion 27c to the emission suppression water storage tank 22. On the other hand, the impurity concentration in the concentrated water is higher than the impurity concentration in the water to be treated. Therefore, the concentrated water is sent from the second outlet part 27d to the heating purification part 28. In addition, you may comprise so that product water may be directly supplied to the dispersion | distribution suppression part 12 as the dispersion | distribution suppression water 7 not via the dispersion | distribution suppression water storage tank 22 from the 1st exit part 27c.

  The drainage separation membrane 27a of the present embodiment is a membrane capable of separating the impurities dissolved in the water to be treated. For example, a nanomembrane having a through hole having a diameter of less than 1 μm, or a reverse osmosis membrane having a reverse osmosis action It is. Thus, impurities that cannot be removed by the wastewater filtration unit 25 that removes the solid matter can be removed by the wastewater separation unit 27a.

  As the wastewater separation membrane 27a, various membranes having different ion or molecule separation ability can be arbitrarily used according to the separation target component in the treated water. The drainage separation unit 27 may be configured by a plurality of drainage separation membranes 27a. For example, a plurality of different types of membranes may be arranged in series in multiple stages, or a plurality of similar membranes may be arranged in parallel in multiple stages. It may be configured. In addition, when a high pressure operation is performed in the drainage separation unit 27, a power recovery mechanism and its control device may be provided for the drainage separation unit 27. Further, a chemical solution introduction mechanism for cleaning the waste water separation membrane 27a, a monitoring mechanism for the waste water separation membrane 27a, and a mechanism for adjusting the generation ratio of production water and concentrated water may be provided in the carbon dioxide recovery system.

  The heat purification unit 28 purifies the concentrated water from the second outlet 27d of the waste water separation unit 27 by heat treatment. Thereby, the said impurity in concentrated water is decomposed | disassembled and detoxified. The heat purification unit 28 detoxifies the nitrogen component and the carbon component in the concentrated water by a known technique such as a wet catalytic oxidation method or a catalytic combustion method. The heat purification unit 28 may include a pretreatment device that performs pretreatment for heat treatment and a concentration adjustment device that adjusts the impurity concentration of concentrated water from the wastewater separation unit 27 according to the temperature and specifications of the heat treatment.

  As described above, the wastewater separation unit 27 of the present embodiment suppresses thermal deterioration, thermal oxidation, decomposition, alteration, and the like of the absorption liquid component when separating impurities contained in the wastewater from the diffusion suppression water storage tank 22. be able to. Therefore, according to the present embodiment, it is possible to realize reuse of waste water while suppressing generation of a volatile organic component from the absorbent component and release of the volatile organic component into the environment. It becomes possible. Furthermore, since the heating energy for performing the heat treatment becomes unnecessary, it becomes possible to reduce the energy consumption of the carbon dioxide recovery system.

  Moreover, the waste water separation part 27 of this embodiment isolate | separates an impurity from waste water, without using the chemical | medical solution for waste water separation. Therefore, according to this embodiment, it becomes possible to suppress the performance fall of the absorption liquid by use of a chemical | medical solution. Moreover, according to this embodiment, since it can suppress that a chemical | medical solution mixes in production water, it becomes possible to improve the amine collection ability of the emission suppression water obtained from production water.

  As described above, according to the present embodiment, it is possible to efficiently supply and use the emission suppressing liquid for recovering the absorbing liquid from the absorbing section exhaust gas 2.

(Second Embodiment)
FIG. 2 is a schematic diagram showing the configuration of the carbon dioxide recovery system of the second embodiment.

  The carbon dioxide recovery system in FIG. 2 includes a drainage supply passage 31 that is an example of a drainage supply passage in addition to the components shown in FIG.

  As described above, the gas purification unit 17 cools the regeneration unit exhaust gas 4 containing carbon dioxide gas, water vapor, and an absorption liquid component, and condenses the water vapor in the regeneration unit exhaust gas 4. As a result, the condensed water containing the absorbent component is discharged from the gas purification unit 17 as the purification unit waste water 6. On the other hand, water vapor and absorption liquid components are removed from the regeneration section exhaust gas 4, and the recovered carbon dioxide gas 5 is discharged from the gas purification section 17. The absorption liquid component removed from the regeneration unit exhaust gas 4 is an example of a predetermined component.

  When the absorption unit 11 and the regeneration unit 15 are compared, since the high-temperature operation is performed in the regeneration unit 15, vaporization and accompanying of the absorption liquid and water are likely to occur. Therefore, a large amount of the purification unit waste water 6 is discharged from the gas purification unit 17, and the purification unit waste water 6 contains a high-concentration absorbent component.

  Therefore, the carbon dioxide recovery system according to the present embodiment treats not only the drainage from the emission suppression water storage tank 22 but also the purification unit drainage 6 from the gas purification unit 17 by the drainage separation unit 27, The drainage supply passage 31 supplies the drainage filtration unit 25. As a result, the purification unit waste water 6 is processed by the waste water filtration unit 25, the sterilization unit 26, the waste water separation unit 27, and the heating purification unit 28 in the same manner as the waste water from the diffusion suppression water storage tank 22.

  Thereby, the amount of water recycled in the carbon dioxide recovery system can be increased. Moreover, since the refinement | purification part waste_water | drain 6 is obtained from the water exposed to the high concentration carbon dioxide environment, it has the advantage that the pH is low. Therefore, when the water to be treated in the wastewater separation unit 27 includes the purification unit wastewater 6, ionization and hydration of organic amines in the water to be treated are promoted, and the separability in the wastewater separation unit 27 is improved. Furthermore, according to this embodiment, the process of the whole waste_water | drain discharged | emitted from a carbon dioxide recovery system can be rationalized, and the operational load of a waste water treatment facility can be reduced.

(Third embodiment)
FIG. 3 is a schematic diagram showing the configuration of the carbon dioxide recovery system of the third embodiment.

  The carbon dioxide recovery system in FIG. 3 includes an acid gas supply unit 32 in addition to the components shown in FIG.

  The acid gas supply unit 32 is disposed between the second valve 24 and the drainage filtration unit 25, and supplies the acid gas to the drainage from the diffusion suppression water storage tank 22. Thereby, the pH of waste water can be reduced. The acid gas supply unit 32 discharges the wastewater whose pH is reduced by the acid gas to the drainage filtration unit 25. Examples of the acid gas are carbon dioxide gas and combustion exhaust gas.

  The acidic gas supply part 32 of this embodiment lowers | hangs the pH of waste water by the gas dissolution principle by the gas-liquid contact of waste water and acidic gas. The gas-liquid contact between the waste water and the acid gas can be performed by a known technique. In addition, when it is desirable to perform an agitation and mixing operation of the water to be treated supplied to the waste water separation unit 19, the acid gas may be supplied to the waste water so that the waste water is stirred in the acid gas supply unit 32. Thereby, ionization and hydration of organic amines in the wastewater are promoted, and the separability in the wastewater separation unit 27 is improved.

  The acid gas may be any gas as long as it is acidic, but is preferably a gas that is present in the carbon dioxide recovery system. An example of such an acid gas is the combustion exhaust gas 1 that flows through a combustion exhaust gas pipe (not shown) from a combustion system such as a thermal power plant toward the absorption unit 11 of the carbon dioxide recovery system. In this case, the combustion exhaust gas 1 is supplied to the absorption unit 11 and the acid gas supply unit 32. Another example of the acid gas is carbon dioxide gas generated in the carbon dioxide recovery system, for example, the recovered carbon dioxide gas 5 discharged from the regeneration unit exhaust gas 4. Thereby, it becomes possible to reduce the cost of preparing acid gas.

  As described above, in the present embodiment, the pH of the waste water can be reduced with an acidic gas instead of a chemical solution. Therefore, according to this embodiment, it becomes possible to suppress the performance fall of the absorption liquid by use of a chemical | medical solution. Moreover, according to this embodiment, since it can suppress that a chemical | medical solution mixes in production water, it becomes possible to improve the amine collection ability of the emission suppression water obtained from production water.

(Fourth embodiment)
FIG. 4 is a schematic diagram showing the configuration of the carbon dioxide recovery system of the fourth embodiment.

  The carbon dioxide recovery system shown in FIG. 4 includes, in addition to the components shown in FIG. And. The to-be-processed water measuring device 33, the production water measuring device 34, and the concentrated water measuring device 35 are examples of one or more measuring devices.

  The to-be-processed water measuring device 33 is arrange | positioned in the inlet part 27b vicinity of the waste_water | drain separation part 27, and measures the physical quantity of the to-be-processed water supplied to the inlet part 27a. The production water measuring instrument 34 is disposed in the vicinity of the first outlet 27c of the waste water separator 27, and measures the physical quantity of the production water discharged from the first outlet 27c. The concentrated water measuring device 35 is disposed in the vicinity of the second outlet 27d of the waste water separator 27, and measures the physical quantity of concentrated water discharged from the second outlet 27d. The measurement results of these physical quantities are output to the control unit 36.

  The control unit 36 includes a physical quantity of water to be treated measured by the water treatment instrument 33, a physical quantity of production water measured by the production water gauge 34, and a physical quantity of concentrated water measured by the concentrated water gauge 35. The wastewater treatment is controlled based on at least one of the following. For example, the control unit 36 controls the operation of the makeup water supply unit 21, the operation of the diffusion suppression water storage tank 22, the opening / closing of the first, second, and third valves 23, 24, 37, the opening degree, and the like. The third valve 37 is provided in the concentrated water flow path from the drainage separation unit 27 to the heating purification unit 28. Examples of the control unit 36 are a computer, a processor, an integrated circuit, a control panel, and the like.

  The to-be-processed water measuring device 33, the production water measuring device 34, and the concentrated water measuring device 35 of this embodiment measure the physical quantity which shows the water quality and water amount of to-be-processed water, production water, and concentrated water, respectively. Examples of such physical quantities are water temperature, pressure, pH, conductivity, flow rate, and an index (for example, concentration) related to organic substances contained in water.

  The control unit 36 confirms the input / output status of the wastewater separation unit 35 based on these physical quantities, adjusts the discharge ratio between the produced water and the concentrated water, or the treated water from the sterilization unit 26 toward the wastewater separation unit 27. Adjust the operating pressure and the amount of treated water. The control unit 36 automatically controls the operation of the wastewater separation unit 27 based on the design plan processing amount in the wastewater separation unit 35 and the quality of the water to be treated. Further, the control unit 36 acquires data on the amount of waste water generated in the carbon dioxide recovery system and the amount of water supply required in the carbon dioxide recovery system, and controls the operation of the waste water separation unit 27 based on these data. Also good.

  As an operation example of the control unit 36, the following is conceivable.

  In the first example, the control unit 36 controls the opening degree of the third valve 37 based on the pressure of the water to be treated. For example, when the pressure of the water to be treated increases, the opening degree of the third valve 37 is decreased, and when the pressure of the water to be treated decreases, the opening degree of the third valve 37 is increased. Thereby, the flow rate of the concentrated water in the third valve 37 can be kept constant.

  In the second example, the control unit 36 controls the operation of the makeup water supply unit 21 based on the production water flow rate. For example, when the flow rate of production water increases, it is not necessary to supply a large amount of make-up water, so the flow rate of make-up water is reduced.

  In the third example, the control unit 36 controls the opening degree of the third valve 37 based on the flow rate of the production water and the flow rate of the concentrated water. For example, the opening degree of the third valve 37 is controlled so that the ratio of the flow rate of the production water and the flow rate of the concentrated water is adjusted to a predetermined value. Thereby, it becomes possible to control the discharge amount of production water and the discharge amount of concentrated water to a suitable balance.

  As described above, according to the present embodiment, it is possible to grasp the state of the wastewater separation unit 27 by measuring the physical quantity of at least one of the water to be treated, the production water, and the concentrated water. It is possible to appropriately control the wastewater treatment in the carbon dioxide recovery system.

  Although several embodiments have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. The novel systems and methods described herein can be implemented in a variety of other forms. Various omissions, substitutions, and changes can be made to the system and method embodiments described in the present specification without departing from the scope of the invention. The appended claims and their equivalents are intended to include such forms and modifications as fall within the scope and spirit of the invention.

1: combustion exhaust gas, 2: absorber exhaust gas, 3: treated gas, 4: regeneration exhaust gas,
5: Recovered carbon dioxide gas, 6: Purified waste water, 7: Emission suppression water, 8: Emission suppression water,
11: Absorption part, 12: Emission suppression part, 13: Rich liquid flow path, 14: Heat exchanger,
15: Regeneration unit, 16: Regeneration unit heater, 17: Gas purification unit, 18: Lean liquid flow path,
21: makeup water supply unit, 22: emission suppression water storage tank, 23: first valve, 24: second valve,
25: Wastewater filtration part, 26: Sterilization part, 27: Wastewater separation part, 27a: Wastewater separation membrane,
27b: inlet part, 27c: first outlet part, 27d: second outlet part, 28: heating purification part,
31: Waste water supply channel, 32: Acid gas supply unit, 33: Water to be treated measuring instrument,
34: Production water measuring device, 35: Concentrated water measuring device, 36: Control unit, 37: Third valve

Claims (8)

An absorption part for absorbing carbon dioxide in the combustion exhaust gas into the absorption liquid;
A regeneration unit for releasing the carbon dioxide from the absorbing liquid that has absorbed the carbon dioxide;
A diffusion suppression unit that collects the absorption liquid accompanying the absorption unit exhaust gas discharged from the absorption unit with a diffusion suppression liquid;
A dispersion suppression liquid holding unit that supplies the diffusion suppression liquid to the diffusion suppression part, collects the diffusion suppression liquid from the diffusion suppression part, and discharges the diffusion suppression liquid as drainage;
A waste liquid separation membrane that separates impurities derived from the absorption liquid from the waste liquid, and the waste liquid from which the impurities are reduced by the waste liquid separation film is supplied as the emission suppressing liquid. A liquid separator,
A carbon dioxide recovery system.   The carbon dioxide recovery system according to claim 1, further comprising a drainage filtration unit that removes solids in the drainage by filtration and supplies the drainage from which the solids have been removed to the drainage separation unit. .   The carbon dioxide recovery system according to claim 1 or 2, further comprising a sterilization unit that sterilizes the drainage and supplies the sterilized drainage to the drainage separation unit. The drainage separation unit is configured to discharge the concentrated liquid in which the impurities are concentrated without passing the drainage liquid through the drainage separation membrane.
The carbon dioxide recovery system according to any one of claims 1 to 3, further comprising a heat purification unit that purifies the concentrated liquid by heat treatment. One or more measuring instruments for measuring a physical quantity of at least one of the drainage liquid, the production liquid, and the concentrated liquid;
A control unit that controls processing of the drainage based on the physical quantity measured by the one or more measuring instruments;
A carbon dioxide recovery system according to claim 4.   The acidic gas supply part which supplies acidic gas to the said waste liquid, and supplies the said waste liquid supplied with the said acidic gas to the said waste liquid separation part is further provided of any one of Claim 1 to 5 Carbon dioxide recovery system. A gas purification unit for removing predetermined components from the regeneration unit exhaust gas discharged from the regeneration unit;
A drainage supply flow path for discharging a purification unit drainage liquid discharged from the gas purification unit and containing the predetermined component to the drainage separation unit;
The carbon dioxide recovery system according to any one of claims 1 to 6, further comprising: In the absorption part, carbon dioxide in the combustion exhaust gas is absorbed by the absorption liquid,
In the regeneration unit, the carbon dioxide is released from the absorption liquid that has absorbed the carbon dioxide,
In the emission suppression unit, the absorption liquid accompanying the absorption part exhaust gas discharged from the absorption part is recovered by the emission suppression liquid,
The emission suppression liquid is supplied from the emission suppression liquid holding unit to the emission suppression unit, the emission suppression liquid is collected from the emission suppression unit to the emission suppression liquid holding unit, and the emission suppression liquid is supplied from the emission suppression liquid holding unit. Is discharged as drainage,
Impurities derived from the absorption liquid are separated from the drainage liquid by a drainage separation membrane, and the production liquid, which is the drainage liquid with the impurities reduced by the drainage separation membrane, is supplied as the emission suppressing liquid.
A carbon dioxide recovery method comprising:

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