JP2010005509A - Device for separating carbon dioxide and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact device for separating carbon dioxide which is higher in the separation capability of carbon dioxide by combining a membrane separation and an absorbing liquid, and suppresses the deterioration of the absorbing performance of carbon dioxide by preventing a carbon-dioxide-absorbing-liquid from oxidation deterioration, and to provide its method. <P>SOLUTION: The device includes a carbon-dioxide-absorber 1 which is provided with a carbon-dioxide-selectively-separation-membrane 3 and to which a gas to be treated is fed, a carbon dioxide separator 2 provided with a hydrophobic membrane 4, and a carbon-dioxide-absorbing-liquid 7 circulating between the carbon-dioxide-absorber 1 and the carbon dioxide separator 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a carbon dioxide separation apparatus and method for separating and recovering carbon dioxide generated when fossil fuel is consumed.

The climate change problem is one of the most serious situations facing the earth today. The trend of global warming has become apparent especially since 1980. Considering the balance between carbon dioxide (CO ₂ ) emissions and natural absorption, the global emissions will not increase in the not-so-distant future. It is said that it must be less than half.

  Currently, 80% of the world's primary energy is fossil fuel, and burning fossil fuel generates carbon dioxide, the center of greenhouse gases. For this reason, carbon dioxide emitted from fossil fuel consumption is recovered and stored in some way, for example, underground storage without being released into the atmosphere, that is, carbon dioxide capture and storage (CCS) technology. Is attracting attention. In the existing CCS technology, the cost for carbon dioxide separation and recovery is said to be 70%, and a separation technology at a low cost (low energy consumption) is required.

  For example, a carbon dioxide recovery system shown in FIG. 7 is known as a carbon dioxide recovery process (Non-Patent Document 1). This carbon dioxide recovery system includes a carbon dioxide absorption tower 51, a combustion gas exhaust gas (treated gas) supply port 9, a treatment gas (decarbonized combustion exhaust gas) discharge port 10, a carbon dioxide separated absorbent 26, and carbon dioxide absorption. Used absorbent 7, carbon dioxide absorbed absorbent transfer pump 54, heat exchanger 55, absorbent regeneration tower 52, regeneration heater 56, reflux pump 58, carbon dioxide separator 53, separation gas (carbon dioxide) 11, regeneration It is composed of a column reflux condenser 57.

  The combustion exhaust gas is introduced into the carbon dioxide absorption tower 51 from the supply port 9, and the combustion exhaust gas is brought into countercurrent contact with the absorption liquid in the absorption tower 51, and the carbon dioxide in the combustion exhaust gas is absorbed and removed by the absorption liquid and decarbonized combustion. The exhaust gas moves upward and is discharged from the discharge port 10. The absorption liquid supplied to the absorption tower 51 absorbs carbon dioxide, and due to the heat of reaction due to the absorption, or due to the sensible heat of the exhaust gas, the temperature becomes higher than that of the absorption liquid 26 that is normally supplied, and the absorption liquid transfer pump 54 Is sent to the heat exchanger 55 to be heated and guided to the absorption liquid regeneration tower 52.

  The temperature of the regenerated absorption liquid can be adjusted by the heat exchanger 55 or, if necessary, a cooler 59 provided between the heat exchanger 55 and the absorption liquid supply port of the absorption tower 51. In the regeneration tower 52, the absorbent is regenerated by heating by the regeneration heater 56, cooled by the heat exchanger 55 and, if necessary, the cooler 59, and returned to the absorption tower 51.

  In the upper part of the absorption liquid regeneration tower 52, the carbon dioxide separated from the absorption liquid comes into contact with the reflux water, is cooled by the regeneration tower reflux cooler 57, and the water vapor accompanying the carbon dioxide is condensed in the carbon dioxide separator 53. Separated from the reflux water, the separated gas (carbon dioxide) is led to a carbon dioxide recovery step.

  Many amine compounds are used as carbon dioxide absorbing liquids used in such systems. For example, in Patent Document 1, a composition for acidic gas scraping containing a non-aqueous solvent such as a sterically hindered amine and sulfolane, and 2-amino-2-methyl-1-propanol or the like is used as the sterically hindered primary monoamino alcohol. Are listed.

  Patent Document 2 discloses 2-amino-2-methyl-1-propanol, 2- (merylamino) -ethanol, 2- (ethylamino) -ethanol, 2- (diethylamino) -ethanol, 2- (hydroxyethyl)- It describes the use of a specific hindered amine aqueous solution, typically a hindered amine selected from the group of piperidines.

  Patent Document 3 describes using an amine mixed aqueous solution in which the concentration of each of the secondary amine and the tertiary amine is in the range of 10 to 45% by weight.

  As described above, it is known that various amine compounds are used as the carbon dioxide absorbing liquid. However, all of them recover carbon dioxide by a method in which the absorbing liquid and the combustion exhaust gas containing carbon dioxide are brought into direct contact with each other. .

  In addition, a system that separates and recovers carbon dioxide in a non-process gas by combining separation with a membrane and an absorbing solution has been proposed.

  For example, in Patent Document 4, as an apparatus for continuously separating polar gas by a membrane separation method, two hydrophobic porous membrane modules, an absorbing liquid for polar gas, a carrier gas for releasing polar gas from the absorbing liquid, and polarity Using a separation membrane module that separates gas and carrier gas, one hydrophobic porous membrane is used as a gas-liquid contact device for polar gas absorption, and polar gas is absorbed and separated into absorption liquid from gas containing polar gas The remaining one of the hydrophobic porous membrane is used as a gas-liquid contactor that diffuses polar gas from a solution that has absorbed polar gas, and polar gas is removed from a solution that has absorbed polar gas using a carrier gas in the diffusion section. A system is disclosed that operates to dissipate and separate the polar and carrier gases using a separation membrane module.

Further, Patent Document 5 discloses that one side of a membrane of an absorber comprising a membrane module is used for the purpose of reducing the energy and cost required to absorb the separation target gas in the absorption process in the chemical absorption method. The gas to be separated is introduced into the gas, the absorption liquid is allowed to flow to the other side, the gas to be separated in the gas to be separated is absorbed into the absorption liquid through the membrane, and at least one of the gas flow and the absorption liquid flow is absorbed in the absorption device. The liquid that has absorbed the separation target gas is disturbed by the flow of the absorption liquid and is introduced into the regeneration tower via a heat exchanger by a pump, and the separation target gas is diffused by heating the absorption liquid in the regeneration tower. A method is disclosed in which the absorption liquid is regenerated and the gas to be separated is cooled and recovered, while the regenerated absorption liquid is pumped through a heat exchanger, introduced into the absorption device after cooling, and used in circulation. The To have.
JP-A-61-71819 JP-A-5-301023 JP-A-8-252430 JP-A-6-99018 JP 2007-283267 A Japan Environmental Technology Research Organization “2006 CO2 fixation and effective utilization technology countermeasure project, CO2 separation and recovery technology development report using low-grade waste heat”, March 2007

In the conventional carbon dioxide recovery system shown in FIG. 7, in order to maintain a predetermined carbon dioxide separation performance, it is necessary to sufficiently secure a gas-liquid contact portion in the absorption tower and the regeneration tower which are gas-liquid contact devices. As a result, there is a problem that the apparatus becomes larger. Further, the combustion exhaust gas contains not only carbon dioxide but also O ₂ , SOx, and NOx. When the absorbent and exhaust gas are in direct contact, there is a problem that the performance of the absorbent is degraded and deteriorated due to the presence of these O ₂ , SOx, and NOx.

Further, in the system described in Patent Document 4, a hydrophobic porous membrane is used, and all components of the gas supplied to the absorption device via the hydrophobic porous membrane come into contact with the absorbing liquid, and combustion occurs. When applied to the separation of carbon dioxide in the exhaust gas, there is a possibility that the performance of the absorbing solution is lowered and deteriorated due to O ₂ , SOx, and NOx contained in the combustion exhaust gas.

Also, in the system described in Patent Document 5, a hydrophobic porous membrane is used, and all the components of the gas supplied to the absorption device through the hydrophobic porous membrane come into contact with the absorbing solution. When applied to the separation of carbon dioxide in combustion exhaust gas, there is a possibility that the performance of the absorbing solution is lowered and deteriorated due to O ₂ , SOx, and NOx contained in the combustion exhaust gas.

  In order to solve the above problems, the object of the present invention is to combine a membrane separation and an absorption liquid, and is compact and has high carbon dioxide separation performance, and also prevents carbon dioxide absorption performance by preventing oxidative deterioration of the carbon dioxide absorption liquid. An object of the present invention is to provide a carbon dioxide separation device and a method thereof in which the decrease in the temperature is suppressed.

  In order to solve the above problems, a carbon dioxide separator and a method thereof according to the present invention include a carbon dioxide absorber provided with a carbon dioxide selective separation membrane and supplied with a gas to be treated, and a carbon dioxide separation provided with a hydrophobic membrane. And a carbon dioxide absorbent that circulates between the carbon dioxide absorber and the carbon dioxide separator.

  According to the present invention, it is possible to provide a carbon dioxide separation apparatus and a method thereof that are compact and have high carbon dioxide separation performance, and that suppresses deterioration in carbon dioxide absorption performance by preventing oxidative deterioration of the carbon dioxide absorption liquid. it can.

  Hereinafter, embodiments of a carbon dioxide separator and method according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram of a carbon dioxide separator according to a first embodiment of the present invention.
This carbon dioxide separator includes a carbon dioxide absorber 1 having a carbon dioxide selective separation membrane 3 inside, a carbon dioxide separator 2 having a hydrophobic membrane 4 inside, and carbon dioxide absorption supplied to the carbon dioxide separator 2. The heat exchanger 5 controls the temperature of the liquid, and the heat exchanger 6 controls the temperature of the carbon dioxide absorbing liquid 7 supplied to the carbon dioxide absorber 1.

  For example, a gas to be treated (treated gas) such as boiler combustion exhaust gas is supplied to the supply port 9 of the carbon dioxide absorber 1, and the treated gas is discharged from the exhaust port 10 of the carbon dioxide absorber 1.

  The carbon dioxide absorbing liquid 7 introduced into the carbon dioxide absorber 1 is discharged from the carbon dioxide absorber 1 after absorbing carbon dioxide from the gas to be treated by the carbon dioxide selective separation membrane 3 in the carbon dioxide absorber 1. Then, the temperature is adjusted to a temperature at which carbon dioxide is easily released from the absorbing solution by the heat exchanger 5, and then supplied to the carbon dioxide separator 2. In the carbon dioxide separator 2, the carbon dioxide in the absorbing liquid is released through the hydrophobic membrane 4, and the separated gas is released and collected from the gas outlet 11 of the carbon dioxide separator 2.

  On the other hand, the carbon dioxide absorbing liquid 7 is discharged from the carbon dioxide separator 2, adjusted to a temperature at which the carbon dioxide is easily absorbed by the heat exchanger 6, and then returned to the carbon dioxide absorber 1. Thus, the carbon dioxide absorbing liquid 7 circulates between the carbon dioxide absorber 1 and the carbon dioxide separator 2 through the heat exchangers 5 and 6.

  In the carbon dioxide absorber 1, the carbon dioxide contained in the gas to be treated moves to the absorption liquid side through the carbon dioxide selective separation membrane 3, and in the processing gas discharged from the gas outlet 10 of the carbon dioxide absorber 1. The carbon dioxide concentration of is reduced.

  In this way, carbon dioxide in the gas to be treated is selectively permeated through the separation membrane by the action of the carbon dioxide selective separation membrane 3 and is contacted and absorbed by the absorption liquid. For this reason, the gas in contact with the absorption liquid has a high carbon dioxide concentration, the carbon dioxide transfer rate from the gas to the absorption liquid increases, and the carbon dioxide absorber is downsized.

  Moreover, since the carbon dioxide absorption liquid can absorb carbon dioxide in the gas to be processed without directly contacting with oxygen, SOx, and NOx contained in the gas to be processed, the oxidation deterioration of the absorption liquid and the deterioration of the absorption performance are suppressed. be able to.

  It is desirable to use a non-porous membrane as the carbon dioxide selective separation membrane 3 provided in the carbon dioxide absorber 1 and the hydrophobic membrane 4 provided in the carbon dioxide separator. As the material, polyimide, polyethylene glycol, amine compound, zeolite or the like can be used.

  In addition, by employing a hollow fiber membrane as the membrane, the gas-liquid contact area per unit volume can be increased, and the carbon dioxide absorber 1 and the carbon dioxide separator 2 can be reduced in size.

  In the case of using a tubular hollow fiber membrane, it is desirable from the viewpoint of pressure loss that the carbon dioxide absorbing liquid is flown into the tube and the gas to be treated is flowed outside the tube.

  Further, by adopting the tubular hollow fiber membrane, the flow rate of the absorbing liquid flowing in the tube can be increased particularly in the carbon dioxide absorber 1, and the carbon dioxide absorber is improved by improving the carbon dioxide absorption rate and the absorption efficiency. Can be improved in performance and size.

  Furthermore, since the movement of carbon dioxide from the gas to be treated to the carbon dioxide absorbing liquid in the carbon dioxide absorber 1 uses the temperature difference between the two phases as a driving force, the gas to be treated and the carbon dioxide absorbing liquid flow countercurrently (dioxide dioxide). The direction of the flow of the carbon absorbent and the gas to be treated is reversed. The average temperature difference between the gas phase and the liquid phase increases, and the carbon dioxide absorption rate and absorption efficiency are improved, so that the carbon dioxide absorber can be improved in performance and size.

  In the carbon dioxide separator 2, carbon dioxide in the absorption liquid is permeated through the hydrophobic membrane 4, but if the gas discharge port of the carbon dioxide separator 2 is connected to a decompression system, the carbon dioxide from the absorption liquid The release of carbon dioxide is further promoted.

  According to the carbon dioxide separator according to the first embodiment, the carbon dioxide selective permeable membrane 3 is applied to the carbon dioxide absorber 1, and the hydrophobic membrane 4 is applied to the carbon dioxide separator 2. By circulating the absorption liquid between the carbon dioxide separators 2, it becomes possible to efficiently separate carbon dioxide from the gas to be treated. As a result, the carbon dioxide separation performance is high, compact, and the carbon dioxide absorption liquid. It is possible to provide a carbon dioxide separation apparatus or method that can prevent oxidative degradation of the carbon dioxide and suppress a decrease in carbon dioxide absorption performance.

(Second Embodiment)
A carbon dioxide separator according to the second embodiment will be described with reference to FIG. In addition, the part which overlaps with 1st Embodiment uses the same code | symbol, and abbreviate | omits description.
The carbon dioxide separator according to the second embodiment is characterized in that two carbon dioxide absorbers are arranged in series.

  The carbon dioxide absorbing liquid 7 supplied from the carbon dioxide separator 2 is introduced into the first carbon dioxide absorber 1a, and the carbon dioxide absorbing liquid 35 discharged from the first carbon dioxide absorber 1a is converted into the second carbon dioxide. The carbon dioxide absorbent 7 supplied to the absorber 1 b and discharged from the second carbon dioxide absorber 1 b is supplied to the carbon dioxide separator 2.

  The gas to be treated is supplied to the gas supply port 9-2 of the second carbon dioxide absorber 1b, and the gas 34 discharged from the gas discharge port 10-2 is supplied to the gas of the first carbon dioxide absorber 1a. The gas is supplied to the port 9-1 and the processing gas is discharged from the gas discharge port 10-1.

  In the second embodiment, an example in which two carbon dioxide absorbers are provided has been described. However, by sequentially connecting the carbon dioxide absorbing liquid line and the gas to be processed line, respectively, three or more carbon dioxide absorbers are configured. Also good.

  According to the second embodiment, by arranging a plurality of carbon dioxide absorbers in series, the carbon dioxide separation performance is further improved, and carbon dioxide can be separated from the gas to be treated with high efficiency. In addition, since the plurality of carbon dioxide absorbers can be laid out freely in both the height direction and the planar direction, the entire carbon dioxide separator can be made compact.

(Third embodiment)
A carbon dioxide separator according to a third embodiment will be described with reference to FIG. In addition, description of the part which overlaps with 1st and 2nd embodiment is abbreviate | omitted.

  The carbon dioxide separator according to the third embodiment has two carbon dioxide absorbers arranged in parallel, and the lines are rearranged corresponding to the flow rate ratio between the carbon dioxide absorbent and the gas to be treated. It is characterized by.

  For the operating conditions in which the flow rate of the carbon dioxide absorbing liquid 7 is relatively increased, the carbon dioxide absorbers 1a and 1b are supplied from the carbon dioxide separator 11 to the supply ports 9-1 and 9-2 of the carbon dioxide absorbing liquid 7. The discharged carbon dioxide absorbing liquid 7 is branched and supplied, and the carbon dioxide absorbing liquid discharged from the carbon dioxide absorbing liquid discharge ports of the carbon dioxide absorbers 1a and 1b is joined and supplied to the carbon dioxide separator 11. To do.

  On the other hand, for the operating conditions where the flow rate of the carbon dioxide absorbing liquid is small and the flow rate of the treated gas is large, the treated gas is branched into the gas supply ports 9-1 and 9-2 of the carbon dioxide absorbers 1a and 1b. Then, the gas to be processed is processed by the carbon dioxide absorbers 1a and 1b.

The carbon dioxide separator according to the third embodiment will be specifically described.
In FIG. 3, the carbon dioxide absorbing liquid 7 discharged from the carbon dioxide separator 2 is branched and supplied to the carbon dioxide absorbing liquid supply ports 9-1 and 9-2 of the carbon dioxide absorbers 1a and 1b. The carbon dioxide absorbing liquid 7 discharged from the carbon absorbers 1 a and 1 b is joined and supplied to the carbon dioxide separator 2.

  The gas to be treated is supplied to the carbon dioxide absorbers 1a and 1b through the branch pipes 41 and 42 to the gas supply ports 9-1 and 9-2 of the carbon dioxide absorbers 1a and 1b. The processing gas is discharged from the merging pipes 43 and 44 through the discharge port 10-1 and the discharge port 10-2.

On-off valves (not shown) are provided in the branch pipes for the carbon dioxide absorption liquid entering and exiting the carbon dioxide absorbers 1a and 1b and the branch pipe for the gas to be processed. Depending on the flow rate, the on-off valve is operated as appropriate to operate the carbon dioxide separator according to the operating conditions.
In the third embodiment, an example in which two carbon dioxide absorbers are provided has been described. However, three or more carbon dioxide absorbers may be used.

  According to the third embodiment, by arranging a plurality of carbon dioxide absorbers in parallel, an operation according to the flow rate of the carbon dioxide absorbing liquid and the flow rate of the gas to be processed is possible, and each carbon dioxide absorption is performed. Concentration changes on the gas side and the absorption liquid side in the chamber are reduced, and control of the carbon dioxide absorber is facilitated. In addition, since the plurality of carbon dioxide absorbers can be laid out freely in both the height direction and the planar direction, the entire carbon dioxide separator can be made compact.

  In addition, although the third embodiment has shown an example in which a plurality of carbon dioxide absorbers are arranged in parallel, groups each having a plurality of carbon dioxide absorbers arranged in series as in the second embodiment are arranged in parallel. By arranging, the same effects as those of the third embodiment described above can be obtained.

(Fourth embodiment)
A carbon dioxide separator according to a fourth embodiment will be described with reference to FIG. Note that a description of the same parts as those in the first to third embodiments is omitted.
The fourth embodiment is characterized in that a solute separator is provided in the circulation path of the carbon dioxide absorbing liquid 7.

  In FIG. 4, a solute separator 21 having a function of separating the solute contained in the carbon dioxide absorbing liquid is provided on the transfer path between the carbon dioxide absorber 1 and the carbon dioxide separator 2 and is discharged from the solute separator 21. The concentrated absorption liquid 24 is supplied to the carbon dioxide separator 2, and the solute separation absorption liquid 25 discharged from the solute separator 21 is merged with the carbon dioxide separated absorption liquid 8 discharged from the carbon dioxide separator 2. A carbon absorbing liquid 26 is supplied to the carbon dioxide absorber 1.

  As the solute separator 21, a device using a membrane such as a reverse osmosis membrane or a pervaporation membrane, or a device using heat such as evaporation and concentration can be applied. In the fourth embodiment, an example in which a reverse osmosis membrane is used as the solute separator 21 will be described.

  The carbon dioxide absorbing solution 7 discharged from the carbon dioxide absorber 1 is pressurized by a pressure pump 22 and supplied to a solute separator 21 composed of a reverse osmosis membrane device. The pressure of the carbon dioxide absorbing liquid is controlled by a pressure regulator 23 provided downstream of the carbon dioxide separator 2. In the solute separator 21, the solvent passes through the reverse osmosis membrane and is discharged as a solute separation / absorption liquid 25. On the other hand, solutes such as carbon dioxide do not permeate the reverse osmosis membrane and are discharged as the concentrated absorbent 24.

  As a result, a part of the solvent is separated from the carbon dioxide absorbing liquid 7 by the solute separator 21, so that the amount of the carbon dioxide absorbing liquid 7 supplied to the carbon dioxide separator 2 is reduced. It is possible to reduce the amount of heat applied when separating the.

  Further, the concentrated absorbent 24 discharged from the solute separator 21 is supplied to the carbon dioxide separator 2 while maintaining the pressurized state. Therefore, the carbon dioxide separator 2 can take a large pressure difference between the carbon dioxide absorbing solution inside the hydrophobic membrane 4 and the gas phase outside the hydrophobic membrane 4, and the carbon dioxide is released from the carbon dioxide absorbing solution. Promoted.

  According to the fourth embodiment, by providing the solute separator on the transfer path between the carbon dioxide absorber and the carbon dioxide separator, the carbon dioxide separation efficiency in the carbon dioxide separator can be further improved. it can.

(Fifth embodiment)
A carbon dioxide separator according to a fifth embodiment will be described with reference to FIG.
This embodiment is characterized in that two solute separators are arranged in series.

In FIG. 5, the carbon dioxide absorption liquid 7 discharged from the carbon dioxide absorber 1 is supplied to the solute separator 21a, and the concentrated absorption liquid 24 discharged from the solute separator 21a is supplied to the solute separator 21b to separate the solute. The concentrated absorption liquid 28 discharged from the vessel 21 b is supplied to the carbon dioxide separator 2, and the solute separation absorption liquid 25 discharged from the solute separators 21 a and 21 b has been separated from the carbon dioxide separator 2 discharged from the carbon dioxide separator 2. It is combined with the carbon dioxide absorbing liquid 7 and supplied to the carbon dioxide absorber 1.
In the above description, an example in which two solute separators are provided has been described, but three or more solute separators may be used.

  According to the fifth embodiment, since a plurality of solute separators are provided, the solute separation performance can be further improved, so that the carbon dioxide separation efficiency in the carbon dioxide separator can be further improved. . In addition, the solute separator can be made into a small unit, and the number of units can be increased or decreased in accordance with the processing amount, the degree of freedom of the apparatus layout is increased, and the entire carbon dioxide separator can be made compact.

(Sixth embodiment)
A carbon dioxide separator according to a sixth embodiment will be described with reference to FIG.
In 6th Embodiment, the carbon dioxide absorption liquid 7 discharged | emitted from the carbon dioxide separator 2 is supplied to the solute separation absorption liquid side of the solute separator 21 which consists of a reverse osmosis membrane apparatus, and carbon dioxide absorption is carried out with a solute separation absorption liquid. Supply to vessel 1.

By passing the absorbent 7 after separation of carbon dioxide on the side of the solute separator 21 through which the solvent of the reverse osmosis membrane permeates, adhesion of dirt and the like on the solvent permeation side of the reverse osmosis membrane is prevented and a permeation flux is secured. be able to.
According to the sixth embodiment, the solute separation performance of the solute separator 21 can be further improved by supplying the carbon dioxide absorbing liquid 7 discharged from the carbon dioxide separator 1 to the solute separator 21. .

  As described above, according to the first to sixth embodiments of the present invention, a carbon dioxide selective permeable membrane is applied to a carbon dioxide absorber and a hydrophobic membrane is applied to a carbon dioxide separator by a combination of membrane separation and absorption liquid. Circulates the absorption liquid between the carbon dioxide absorber and the carbon dioxide separator, and separates the solute contained in the carbon dioxide absorption liquid on the transfer path of the carbon dioxide absorption liquid from the carbon dioxide absorber to the carbon dioxide separator. By providing a solute separator having the following, carbon dioxide can be efficiently separated from the gas to be treated, and the following effects are obtained.

(1) A compact carbon dioxide separator having high carbon dioxide separation performance can be realized.
(2) It is possible to realize a carbon dioxide recovery method that prevents the oxidative deterioration of the carbon dioxide absorbing liquid and suppresses a decrease in carbon dioxide absorbing performance.
(3) The amount of carbon dioxide absorbing liquid supplied to the carbon dioxide separator is reduced, and the amount of heat given when carbon dioxide is separated from the carbon dioxide absorbing liquid can be reduced.

(4) The release of carbon dioxide from the carbon dioxide absorbing liquid is promoted, and the carbon dioxide separator can be miniaturized.
(5) Since the solute separator is made into a small unit and the number of units is increased / decreased according to the processing amount, it can be laid out both in the height direction and in the plane direction, so the degree of freedom can be set even if there are restrictions on the installation area and height High device layout is possible.

  In addition, although each individual feature was described about this embodiment, it is needless to say that each effect can be obtained by implementing each embodiment in an appropriate combination.

1 is an overall configuration diagram of a carbon dioxide separator according to a first embodiment of the present invention. The block diagram of the carbon dioxide separator which concerns on the 2nd Embodiment of this invention. The block diagram of the carbon dioxide separator which concerns on the 3rd Embodiment of this invention. The block diagram of the carbon dioxide separator which concerns on the 4th Embodiment of this invention. The block diagram of the carbon dioxide separator which concerns on the 5th Embodiment of this invention. The block diagram of the carbon dioxide separator which concerns on the 6th Embodiment of this invention. The whole block diagram of the conventional carbon dioxide separator.

Explanation of symbols

  1, 1a, 1b ... carbon dioxide absorber, 2 ... carbon dioxide separator, 3 ... carbon dioxide selective separation membrane, 4 ... hydrophobic membrane, 5, 6 ... heat exchanger, 7, 26 ... carbon dioxide absorbent, 9 , 9-1, 9-2... Supply port, 10, 10-1, 10-2 ... discharge port, 11 ... discharge port, 21, 21a, 21b ... solute separator, 22 ... pressure pump, 23 ... pressure adjustment 24 ... Concentrated absorption liquid, 25 ... Solute separation absorption liquid, 26 ... Supply absorption liquid, 28 ... Concentration absorption liquid, 29 ... Solute separation absorption liquid, 43, 44 ... Piping, 51 ... Absorption tower, 52 ... Regeneration tower, 53. Separator.

Claims (13)

  A carbon dioxide absorber having a carbon dioxide selective separation membrane to which a gas to be treated is supplied; a carbon dioxide separator having a hydrophobic membrane; and a carbon dioxide circulated between the carbon dioxide absorber and the carbon dioxide separator. And a carbon absorption liquid.   It further comprises a heat exchanger that controls the temperature of the carbon dioxide absorbent supplied to the carbon dioxide absorber, and a heat exchanger that controls the temperature of the carbon dioxide absorbent supplied to the carbon dioxide separator. Then, the carbon dioxide separator according to claim 1.   3. The carbon dioxide separator according to claim 1, wherein the carbon selective separation membrane and the hydrophobic membrane are hollow fiber membranes or tubular membranes.   The carbon dioxide separator according to claim 3, wherein the hollow fiber membrane or tubular membrane is non-porous.   The carbon dioxide separator according to claim 3 or 4, wherein an absorption liquid is supplied to the inside of the hollow fiber membrane or the tubular membrane, and a gas to be treated is supplied to the outside.   6. The carbon dioxide separator according to claim 1, wherein the flow direction of the carbon dioxide absorption liquid in the carbon dioxide absorber and the flow direction of the gas to be processed are counterflows.   The carbon dioxide separator according to claim 1, wherein a plurality of the carbon dioxide absorbers are arranged in series.   The carbon dioxide separator according to any one of claims 1 to 7, wherein a plurality of the carbon dioxide absorbers are arranged in parallel.   A solute separator is provided in a circulation path between the carbon dioxide absorber and the carbon dioxide separator, and a solute separation absorption liquid discharged from the solute separator is supplied to the carbon dioxide absorber. The carbon dioxide separator according to any one of claims 1 to 8.   The carbon dioxide separator according to claim 9, wherein a plurality of the solute separators are arranged in series.   The carbon dioxide separator according to claim 9 or 10, wherein the solute separator is a device using a reverse osmosis membrane.   12. The carbon dioxide separator according to claim 9, wherein the carbon dioxide absorbing liquid discharged from the carbon dioxide separator is supplied to a solute separation absorbing liquid side of the solute separator.   A carbon dioxide separation method using the carbon dioxide separator according to any one of claims 1 to 12.

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