WO2014098154A1 - Carbon dioxide collection device and method for operating said collection device - Google Patents

Carbon dioxide collection device and method for operating said collection device Download PDF

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Publication number
WO2014098154A1
WO2014098154A1 PCT/JP2013/083964 JP2013083964W WO2014098154A1 WO 2014098154 A1 WO2014098154 A1 WO 2014098154A1 JP 2013083964 W JP2013083964 W JP 2013083964W WO 2014098154 A1 WO2014098154 A1 WO 2014098154A1
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Prior art keywords
absorption liquid
carbon dioxide
absorption
regeneration tower
tower
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PCT/JP2013/083964
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French (fr)
Japanese (ja)
Inventor
横山　公一
▲高▼本　成仁
小林　和樹
島村　潤
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バブコック日立株式会社
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Publication of WO2014098154A1 publication Critical patent/WO2014098154A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1425—Regeneration of liquid absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • B01D53/1475—Removing carbon dioxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
    • B01D2252/20—Organic absorbents
    • B01D2252/204—Amines
    • B01D2252/20478—Alkanolamines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

  • the present invention relates to a technique for recovering carbon dioxide from the exhaust gas of a combustion apparatus such as a boiler, and more specifically, to a reduction in the amount of water vapor supplied to the flue gas treatment apparatus.
  • CO 2 carbon dioxide
  • COP3 Kyoto Conference on Global Warming Prevention
  • Non-Patent Document 1 an apparatus called a reboiler that is also used in a distillation column is used (see Non-Patent Document 1).
  • the steam for heating the absorption liquid in the regeneration tower is a part of the steam generated by the heat of the combustion device, so that the steam consumption of the CO 2 recovery device can be increased in order to increase the thermal efficiency of the combustion device. It is necessary to reduce as much as possible. Therefore, conventionally, the absorption liquid conveyed from the absorption tower to the regeneration tower by the liquid-liquid heat exchanger is heated by the absorption liquid (CO 2 lean absorption liquid) conveyed from the regeneration tower to the absorption tower, and conveyed to the absorption tower.
  • the absorption liquid CO 2 lean absorption liquid
  • Non-Patent Document 2 The CO 2 lean absorption liquid to be cooled was cooled (see Non-Patent Document 2).
  • the liquid-liquid heat exchanger alone usually does not provide sufficient heat exchange.
  • Patent Document 2 it is necessary to further reduce the temperature of the absorption liquid conveyed from the regeneration tower to the absorption tower. There is also a case.
  • the absorption liquid conveyed from the regeneration tower to the absorption tower can be lowered in temperature, and the absorption liquid temperature in the absorption tower is also lowered.
  • This method is excellent in that steam condensate, which has not been considered in the past, is used for preheating the absorbent.
  • the temperature of the steam condensate is usually a high temperature close to the heating steam temperature.
  • the CO 2 -rich absorbing liquid is more likely to liberate CO 2 gas as the liquid temperature becomes higher (see Non-Patent Document 3), so that the CO 2 gas rapidly increases at the contact surface with the high-temperature liquid. There is a possibility of causing flushing to be released, and there is a problem in actual operability of the apparatus.
  • the present invention has been made on the basis of this, and the problem to be solved is that, in the carbon dioxide recovery apparatus and the operation method thereof, the absorption liquid conveyed from the regeneration tower to the absorption tower is heated to adjust the liquid temperature. It is in the point which implement
  • the present invention is directed to contacting a combustion exhaust gas containing carbon dioxide with an absorption liquid containing water and alkanolamine, and absorbing the carbon dioxide into the absorption liquid, and the carbon dioxide
  • the absorption liquid that has absorbed the water is heated, the carbon dioxide is liberated from the absorption liquid and recovered to regenerate the absorption liquid, and the carbon dioxide is absorbed and transported from the absorption tower to the regeneration tower
  • the carbon dioxide recovery device comprising a first heat exchanger that liberates the carbon dioxide and heats it with the absorbent transported from the regeneration tower to the absorption tower.
  • a hot water is extracted and discharged into a container adjusted to a pressure lower than that of the primary steam to generate secondary hot water and secondary steam, and the carbon dioxide is absorbed from the absorption tower.
  • the present invention provides the recovery apparatus, wherein the absorption liquid liberated the carbon dioxide is extracted from the regeneration tower, heated with primary steam higher than atmospheric pressure and returned to the regeneration tower, and the primary steam is recovered.
  • the secondary hot water having a temperature lower than that of the primary hot water and the secondary steam having a pressure lower than that of the primary steam are generated from the primary hot water generated by condensation, and the carbon dioxide is absorbed to generate the regeneration tower from the absorption tower.
  • the absorption liquid conveyed to the tank is heated with the secondary hot water, and the secondary steam is pressurized to join the primary steam.
  • the absorption liquid from which the carbon dioxide has been liberated is withdrawn from the regeneration tower and released into a container adjusted to a pressure lower than that of the regeneration tower.
  • the absorption liquid may be supplied to the first heat exchanger to absorb the carbon dioxide and heat the absorption liquid conveyed from the absorption tower to the regeneration tower.
  • the absorption liquid liberated the carbon dioxide is extracted from the regeneration tower to generate absorption liquid vapor and absorption liquid at a temperature lower than that of the absorption liquid extracted from the regeneration tower. And pressurizing the low-temperature absorption liquid vapor to return to the regeneration tower, supplying the low-temperature absorption liquid to the heat exchanger, absorbing the carbon dioxide, and transporting the carbon dioxide from the absorption tower to the regeneration tower. What is necessary is just to heat the absorbing liquid.
  • the absorption liquid conveyed from the regeneration tower to the absorption tower is heated to raise the liquid temperature, and the regeneration tower without changing the water vapor supply conditions. It is possible to simultaneously reduce the amount of water vapor supplied to the water. That is, according to the present invention, the temperature of the rich absorption liquid (the absorption liquid that absorbs carbon dioxide and is transported from the absorption tower to the regeneration tower) can be adjusted in a wider range than the conventional method, and is supplied to the regeneration tower.
  • FIG. 1 and FIG. 2 show the results of experiments comparing the device performance of the carbon dioxide recovery device according to the first and second embodiments and the conventional carbon dioxide recovery device shown in FIG. 3 and FIG. FIG.
  • FIG. 1 and 2 are schematic diagrams showing a processing system of a CO 2 recovery apparatus according to the present invention
  • FIG. 1 is a processing system diagram of the first embodiment
  • FIG. 2 is a diagram of the second embodiment.
  • It is a processing system diagram. 3 and 4 are schematic views showing a processing system of a conventional CO 2 recovery apparatus
  • FIG. 3 is a diagram showing an example of a conventional processing system
  • FIG. 4 is another example of a conventional processing system.
  • FIG. In each figure, the same or similar components are denoted by the same reference numerals.
  • a CO 2 recovery device (hereinafter referred to as a recovery device or device) brings a combustion exhaust gas 1 containing CO 2 into contact with an absorption liquid containing water and alkanolamine.
  • the absorbent having absorbed CO 2 (hereinafter, the rich absorbent solution that) heating 9, collected and to liberate CO 2 from the rich absorbing liquid 9 Te play the rich absorbing liquid 9 regenerator 10 and the absorption liquid which is conveyed to the regenerator 8 CO 2 from the absorption tower 7 to absorb (rich absorbing fluid 9) and to release the CO 2 regeneration tower 8
  • the first heat exchanger 3 is configured to be heated with an absorption liquid (hereinafter referred to as a lean absorption liquid) 10 conveyed to the absorption tower 7.
  • the recovery device transports at least a part of the absorption liquid (rich absorption liquid 9) that has absorbed CO 2 by the absorption tower 7 to the regeneration tower 8, and absorbs the CO 2 by the regeneration tower 8 (lean absorption).
  • At least a part of the liquid 10) is conveyed to the absorption tower 7 as a CO 2 absorbing liquid, that is, an absorbing liquid containing water and alkanolamine.
  • the absorption liquid (rich absorption liquid 9) conveyed from the absorption tower 7 to the regeneration tower 8 and the absorption liquid (lean absorption liquid 10) conveyed from the regeneration tower 8 to the absorption tower 7 are subjected to heat exchange, thereby performing rich absorption.
  • the liquid 9 is heated and the lean absorbing liquid 10 is cooled.
  • the recovery device extracts the absorption liquid (lean absorption liquid 10) from which CO 2 has been released from the regeneration tower 8 and heats it with primary steam (hereinafter referred to as reboiler steam) 34 higher than atmospheric pressure to regenerate.
  • primary steam hereinafter referred to as reboiler steam
  • the recovery device allows the reboiler water vapor 34 having a pressure higher than the atmospheric pressure to pass through the inside of the pipe or container that is in contact with the lean absorbent 10 conveyed from the regeneration tower 8 to the absorption tower 7.
  • a heating mechanism hereinafter referred to as a first mechanism
  • a primary hot water 35 generated from the reboiler steam 34 in the pipe or container are supplied to the first flash tank 32a adjusted to a pressure lower than that of the reboiler steam 34. While being supplied and flash-evaporated, it is separated into flash steam 39 and secondary hot water 37 having a temperature lower than that of the primary hot water 35, and the rich absorbent 9 transported from the absorption tower 7 to the regeneration tower 8 by the secondary hot water 37.
  • a mechanism that heats the water vapor, and the flash water 39 is pressurized into a tube or container that pressurizes the flash water vapor 39 and contacts the lean absorbent 10.
  • Mechanism for passing the gas 39 (hereinafter, referred to as a third mechanism) have.
  • the operation method of such a recovery apparatus is that the absorption liquid liberated from CO 2 (lean absorption liquid 10) is extracted from the regeneration tower 8 and heated by the reboiler steam 34 having a pressure higher than the atmospheric pressure. 8 back, to generate a low-temperature secondary heat water 37 and the low pressure flash steam 39 than reboiler for vapor 34 than the primary heat water 35 from primary heat water 35 produced by condensing a reboiler for vapor 34, CO 2
  • the absorption liquid (rich absorption liquid 9) conveyed from the absorption tower 7 to the regeneration tower 8 is heated with the secondary hot water 37, and the flash water vapor 39 is pressurized and merged with the reboiler water vapor 34. ing.
  • the processing system of the conventional apparatus shown in FIG. 3 is also referred to as an example of the recovery apparatus including the basic configuration.
  • the combustion exhaust gas 1 is supplied to the absorption tower 7 by a blower 22.
  • the lean absorbent 10 that has liberated CO 2 in the regeneration tower 8 is cooled by the first heat exchanger 3, sucked by the pump 14 a, further cooled by the cooler 5 a, and conveyed to the absorption tower 7. Yes.
  • the lean absorbing liquid 10 conveyed to the absorption tower 7 passes through the packed bed 11a, the lean absorbing liquid 10 comes into contact with the combustion exhaust gas 1 to absorb CO 2 from the combustion exhaust gas 1, and absorbs rich CO 2 (rich absorption).
  • Liquid 9) is collected in the lower tank 30 of the absorption tower 7.
  • the absorption tower 7 is provided with a CO 2 absorption section at an intermediate portion in the vertical direction.
  • the CO 2 absorption section removes CO 2 from the combustion exhaust gas 1 by bringing the absorption liquid spray section 13 to spray the lean absorption liquid 10 into contact with the lean absorption liquid 10 sprayed from the absorption liquid spray section 13 and the combustion exhaust gas 1. It has a packed bed 11a to be recovered.
  • the combustion exhaust gas 1 ascends the packed bed 11a of the absorption tower 7, it comes into contact with the lean absorbent 10 flowing down from the upper part of the packed bed 11a to remove CO 2 .
  • the lean absorbent 10 comes into contact with the combustion exhaust gas 1 and absorbs CO 2 contained in the combustion exhaust gas 1.
  • the mist and vaporous amine are collected and cooled in the water washing part 23 provided at the upper part of the CO 2 absorption part.
  • the water washing part 23 circulates the water spray part 12 which sprays the washing water 17 on the exhaust gas 16 after CO 2 removal, the collector 18 which stores the washing water 17, the cooler 5b which cools the washing water 17, and the washing water 17. It has a pump 14b.
  • the exhaust gas 16 after the removal of vaporous amine and cooled CO 2 by the water washing section 23 is released into the atmosphere, for example, after the mist is collected in the packed bed 11b provided in the upper part of the absorption tower 7. Is done.
  • the rich absorbent 9 collected in the lower tank 30 of the absorption tower 7 is heated by the first heat exchanger 3 and then transported to the regeneration tower 8 to generate steam generated by the reboiler 21 while passing through the packed bed 11c. Heated by 42 liberates CO 2 .
  • the regeneration tower 8 is provided with a CO 2 liberation part in the middle part in the vertical direction.
  • the CO 2 liberating part includes an absorbing liquid spraying part 15 for spraying the rich absorbing liquid 9, a rich absorbing liquid 9 sprayed from the absorbing liquid spraying part 15, and a vapor rising from the lower part of the regeneration tower 8 (steam of the lean absorbing liquid 10).
  • a water washing spray part 26 for spraying the reflux water 19 and a packed bed (demister) 11d for collecting mist from the CO 2 released by the CO 2 releasing part are provided. .
  • CO 2 liberated by CO 2 free portion the mist is captured when passing through a packed bed (demister) 11d, is recovered as CO 2 gas from the top of the regenerator 8.
  • the CO 2 gas discharged from the regeneration tower 8 is cooled by a cooler (gas cooler) 5 c and then separated into a CO 2 gas 27 and a reflux water 19 by a CO 2 separator 20.
  • the separated reflux water 19 is pressurized by the pump 14 c and supplied to the water washing spray unit 26.
  • the separated CO 2 gas 27 is sent to, for example, a liquefaction facility (not shown).
  • the absorbing solution (lean absorbing solution) 10 after the liberation of CO 2 is collected in the lower tank 31 of the regeneration tower 8.
  • the collected lean absorbent 10 is sent to the reboiler 21 and heated.
  • Part or all of the primary hot water 35 in which the reboiler steam 34 is condensed is separated into the reboiler steam 34 and the separated hot water 43 by the steam separator 40.
  • the separated reboiler steam 34 is supplied for heating the reboiler 21.
  • the reboiler water vapor 34 is adjusted to a pressure higher than the atmospheric pressure, and the reboiler 21 heats the lean absorbent 10 by the reboiler water vapor 34 passing through the inside of the tube or the container. That is, the reboiler 21 corresponds to a first mechanism.
  • the separated hot water 43 is supplied to the third heat exchanger 36 and used to heat the rich absorbent 9.
  • the absorption liquid (lean absorption liquid 10) after liberation of CO 2 is cooled by heat exchange with the rich absorption liquid 9 in the first heat exchanger 3, and is conveyed to the absorption tower 7 by the pump 14a.
  • the rich absorbent 9 absorbs heat from the lean absorbent 10 in the first heat exchanger 3 and is heated. Thereby, the lean absorbent 10 (in other words, the rich absorbent 9) is regenerated as an absorbent for absorbing CO 2 from the combustion exhaust gas 1 (an absorbent containing water and alkanolamine). .
  • the recovery device uses a part or all of the primary hot water 35 condensed with the reboiler water vapor 34 as an absorption liquid after CO 2 release (
  • the secondary hot water 37 and the flash steam 39 which are supplied to the first flash tank 32a different from the lean absorbent 10) and depressurized to lower the temperature, are pressurized by the first compressor 33a to generate VR steam 38.
  • the mechanism is added.
  • the first flash tank 32a is adjusted to a pressure lower than that of the reboiler steam 34, but by providing the first compressor 33a, the difference between the pressure inside the first flash tank 32a and the primary hot water 35 is provided. It is possible to adjust the pressure (flash pressure).
  • the flash pressure can be adjusted, the generation amount of the flash water vapor 39 and the temperature of the secondary hot water 37 can be controlled.
  • the temperature of the secondary hot water 37 can be adjusted, and the secondary hot water 37 can be used to prevent overheating of the rich absorbent 9 in the third heat exchanger 36.
  • the first flash tank 32a and the third heat exchanger 36 correspond to a second mechanism.
  • the VR steam 38 can be used for heating the reboiler 21. That is, the first compressor 33a corresponds to a third mechanism.
  • the supply amount of the reboiler water vapor 34 can be reduced by an amount equivalent to the VR water vapor 38.
  • the recovery device uses an absorption liquid (lean absorption liquid 10) that liberates CO 2.
  • Absorption liquid vapor hereinafter, referred to as a primary lean absorption liquid 10a extracted from the regeneration tower 8 and discharged into a container adjusted to a lower pressure than the regeneration tower 8 and extracted from the regeneration tower 8 (hereinafter referred to as a primary lean absorption liquid).
  • the secondary lean absorbent 10b is supplied to the first heat exchanger 3, absorbs CO 2 and is transported from the absorption tower 7 to the regeneration tower 8 (rich absorbent 9 ) Is heating.
  • the recovery apparatus has an absorption liquid (primary lean absorption liquid 10a) transported from the regeneration tower 8 to the absorption tower 7 in addition to the above-described three mechanisms of the first mechanism to the third mechanism.
  • absorption liquid primary lean absorption liquid 10a
  • the second flash tank 32 b adjusted to a lower pressure than the regeneration tower 8 and flashed.
  • the operation method of the recovery apparatus is that the absorption liquid (lean absorption liquid 10) from which CO 2 has been liberated is extracted from the regeneration tower 8, and from the absorption liquid (primary lean absorption liquid 10a) extracted from the regeneration tower 8.
  • the low-temperature VR absorption liquid vapor 41 and the secondary lean absorption liquid 10b lower than the primary lean absorption liquid 10a are generated, the VR absorption liquid vapor 41 is pressurized and returned to the regeneration tower 8, and the secondary lean absorption liquid 10b is recovered.
  • the absorption liquid from the absorption tower 7 to absorb the CO 2 is transported to the regenerator 8 to heat the (rich absorbing fluid 9), the first embodiment described above This is added to the operation method of the recovery device (FIG. 1).
  • the recovery device has a configuration in which a second flash tank 32b and a second compressor 33b are further added to the recovery device (FIG. 1) according to the first embodiment described above. That is, in the present embodiment, the recovery device supplies the lean absorbing liquid 10 of the regeneration tower 8 to the second flash tank 32b, generates steam by reducing the pressure, and adds the generated steam to the second compressor 33b. A mechanism for supplying pressure to the regeneration tower 8 is provided. In such a recovery apparatus, the liquid temperature of the lean absorbing liquid 10 decreases in the second flash tank 32b and in the first heat exchanger 3.
  • the vapor of the lean absorbing liquid 10 in the second flash tank 32b is pressurized and heated by the second compressor 33b to become the VR absorbing liquid vapor 41, and the VR absorbing liquid vapor 41 is supplied to the regeneration tower 8. . That is, the second flash tank 32b and the second compressor 33b correspond to a fourth mechanism.
  • the VR absorption liquid vapor 41 supplied to the regeneration tower 8 is used for heating the regeneration tower 8 together with the steam 42 from the reboiler 21.
  • the supply amount of the reboiler water vapor 34 can be reduced by an amount corresponding to the VR absorption liquid vapor 41 compared to the first embodiment (FIG. 1).
  • the secondary lean absorbent 10b obtained by flash evaporation of the primary lean absorbent 10a supplied to the second flash tank 32b is used to heat the rich absorbent 9 in the first heat exchanger 3. . That is, the first heat exchanger 3, the second flash tank 32b, and the second compressor 33b correspond to a fifth mechanism. As in the first embodiment, in the third heat exchanger 36, the rich absorbent 9 transported to the regeneration tower 8 is heated by the secondary hot water 37 obtained by flushing the primary hot water 35 from the reboiler 21. It is also possible to do.
  • the recovery device does not include a mechanism for heating the rich absorbent 9 with the secondary hot water 37 from the reboiler 21.
  • such a recovery device does not include a mechanism that generates the VR steam 38 for pressurizing the flash steam 39 and heating the reboiler 21.
  • the recovery device does not have the third heat exchanger 36 for adjusting the temperature of the rich absorbent 9. Therefore, in such a recovery apparatus, the liquid temperature of the rich absorbent 9 supplied to the regeneration tower 8 is lowered.
  • Example 1 In the experiment, the temperature of the combustion exhaust gas 1 and the liquid temperature of the lean absorbent 10 at the inlet of the absorption tower 7 are 40 ° C., the internal pressure of the regeneration tower 8 is 160 kPa (gauge), and the liquid temperature of the lean absorbent 10 in the regeneration tower 8.
  • the reboiler steam 34 temperature is 140 ° C.
  • the cooler temperature is 30 ° C.
  • the amount of combustion exhaust gas 1 is 500 m 3 / h
  • the liquid gas ratio is 3.0 (L / m 3 )
  • the amount of circulating fluid Was set to 1500 L (hereinafter, these set values are collectively referred to as experimental conditions).
  • CO 2 contained in the combustion exhaust gas 1 is removed by the absorption tower 7 and collected as the rich absorbent 9 in the lower tank 30 of the absorption tower 7.
  • the collected rich absorbent 9 is heated by the first heat exchanger 3 and then conveyed to the regeneration tower 8.
  • the rich absorbent 9 is further heated by the reboiler 21 to liberate CO 2 and recovered as a lean absorbent 10 in the lower tank 31 of the regeneration tower 8.
  • the collected lean absorbent 10 is conveyed again to the absorption tower 7 via the first heat exchanger 3.
  • the primary hot water 35 discharged from the reboiler 21 is supplied to the first flash tank 32a, and the obtained secondary hot water 37 is supplied to the third heat exchanger 36.
  • the flash steam 39 obtained simultaneously with the secondary hot water 37 was pressurized by the first compressor 33a until it reached 140 ° C.
  • the VR water vapor 38 thus obtained was used as heating steam for the reboiler 21.
  • As the lean absorbing solution 10 a 30% MEA (monoethanolamine) solution was used.
  • a kettle type is used as the reboiler 21, but a thermosiphon type reboiler can also be used.
  • Example 2 As shown in FIG. 2, in this embodiment, the lean absorbent 10 (primary lean absorbent 10a) before passing through the first heat exchanger 3 is flash-evaporated in the second flash tank 32b, and the obtained primary is obtained.
  • the vapor of the lean absorbent 10a is pressurized by the second compressor 33b to generate the VR absorbent vapor 41.
  • the generated VR absorption liquid vapor 41 is supplied to the regeneration tower 8, and the lean absorption liquid 10 (secondary lean absorption liquid 10 b) in the second flash tank 32 b is supplied to the first heat exchanger 3.
  • the rest of the apparatus configuration and experimental conditions were the same as in Example 1 described above.
  • Comparative Example 1 As shown in FIG. 3, in this comparative example, the primary hot water 35 discharged from the reboiler 21 is separated into reboiler steam 34 and separated hot water 43 by the steam separator 40.
  • the reboiler steam 34 is supplied for heating the reboiler 21, and the separated hot water 43 is used to heat the rich absorbent 9 transported from the absorption tower 7 to the regeneration tower 8.
  • the rest of the apparatus configuration and experimental conditions were the same as in Example 1 described above. However, this comparative example does not have an apparatus configuration including the first flash tank 32a and the first compressor 33a.
  • Comparative Example 2 As shown in FIG. 4, in this comparative example, a mechanism for supplying secondary hot water 37 obtained by flash evaporation of the primary hot water 35 to the third heat exchanger 36, and the secondary hot water 37 simultaneously. A mechanism for supplying the obtained VR water vapor 38 to heat the reboiler 21 is not provided. Other apparatus configurations and experimental conditions were the same as those in Example 2 described above.
  • FIG. 5 is a diagram illustrating experimental results in the apparatuses according to Examples 1 and 2 and Comparative Examples 1 and 2 described above.
  • FIG. 5 shows the liquid temperature values at the inlet and outlet of the regeneration tower 8 in each apparatus.
  • FIG. 5 shows the CO 2 concentration in the lean absorbent 10 at the outlet of the regeneration tower 8 in each apparatus according to Examples 1 and 2 and Comparative Example 2, and the value in the apparatus according to Comparative Example 1 as 1.
  • the relative value is shown.
  • FIG. 5 when the supply amount of water vapor (reboiler water vapor 34) to the reboiler 21 in each device according to Examples 1 and 2 and Comparative Example 2 is set to 100 in the device according to Comparative Example 1 The relative value is shown.
  • Comparative Example 1 As shown in FIG. 5, in Comparative Example 1 and Examples 1 and 2, the rich absorbent (CO 2 rich amine) 9 transported to the regeneration tower 8 is heated by the third heat exchanger 36, so that Comparative Example 2 The liquid temperature of the rich absorbent 9 at the inlet of the regeneration tower 8 is higher than that.
  • Comparative Example 1 a phenomenon in which the pressure in the upper part of the regeneration tower 8 changes was observed. This is presumably because the temperature of the primary hot water 35 is close to 140 ° C., so that CO 2 is liberated from a part of the rich absorbent 9 and flashed as described above.
  • Example 1 since the temperature of the secondary hot water 37 was greatly reduced, the phenomenon as in Comparative Example 1 did not occur.
  • Example 2 the supply amount of the reboiler water vapor 34 to the reboiler 21 can be reduced as compared with Comparative Example 1, but in Comparative Example 2, the rich absorbent 9 at the inlet of the regeneration tower 8 is reduced. Since the liquid temperature was low and the flash water vapor 39 from the primary hot water 35 was not used, the supply amount of the reboiler water vapor 34 was larger than that in Example 2 and was equivalent to that in Example 1.
  • the carbon dioxide recovery apparatus and the operation method thereof according to the first embodiment (FIG. 1) and the second embodiment (FIG. 2) of the present invention the carbon dioxide is transported from the regeneration tower 8 to the absorption tower 7. It is possible to simultaneously increase the liquid temperature by heating the lean absorbent 10 and reduce the amount of water vapor supplied to the regeneration tower 8 without changing the water vapor supply conditions. That is, according to the present invention, the temperature of the rich absorbent 9 conveyed to the regeneration tower 8 can be adjusted in a wider range than the conventional method, so that the lean absorbent is reduced while reducing the amount of steam supplied to the regeneration tower 8. It is also possible to reduce 10 CO 2 loading.

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  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
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Abstract

[Problem] In a carbon dioxide collection device and an operation method therefor, to simultaneously achieve an increase in absorption liquid temperature by heating absorption liquid that is being transported from a regeneration column to an absorption column and a reduction of the volume of steam supplied to the regeneration column without changing the conditions for steam supply. [Solution] Primary hot water (35) from a reboiler (21) of the regeneration column (8) is flashed to generate a flashed steam (39); the flashed steam is compressed to generate a VR steam (38) and is supplied to the reboiler; and post-flashing secondary hot water (37) is used as a heat source for heating a rich absorption liquid (9) that is transported to the regeneration column. When doing so, a VR absorption liquid steam (41) obtained by flashing a lean absorption liquid (10) that is transported from the regeneration column to the absorption column (7) can be pressurized and supplied to the regeneration column.

Description

二酸化炭素の回収装置、及び該回収装置の運転方法Carbon dioxide recovery device and method of operating the recovery device
　本発明は、ボイラなどの燃焼装置の排ガス中から二酸化炭素を回収する技術、具体的には、排煙処理装置に供給する水蒸気量の低減化に関する。 The present invention relates to a technique for recovering carbon dioxide from the exhaust gas of a combustion apparatus such as a boiler, and more specifically, to a reduction in the amount of water vapor supplied to the flue gas treatment apparatus.
　従来から、火力発電所等において、石炭などの化石燃料の燃焼に伴って二酸化炭素（ＣＯ２）が発生し、大気中のＣＯ２濃度を上昇させており、それに伴う気温の上昇によって各種の環境問題が生じると言われてきた。そこで、地球温暖化の防止を図るべく、１９９７年１２月に温暖化防止京都会議（ＣＯＰ３）で京都議定書が採択された。かかる議定書は２００５年２月に発効し、各国においてＣＯ２放出量の削減対策が実施されてきている。 Conventionally, carbon dioxide (CO 2 ) has been generated along with combustion of fossil fuels such as coal in thermal power plants and the like, and the concentration of CO 2 in the atmosphere has been increased. It has been said that problems will arise. Therefore, in order to prevent global warming, the Kyoto Protocol was adopted in December 1997 at the Kyoto Conference on Global Warming Prevention (COP3). This protocol entered into force in February 2005, and measures to reduce CO 2 emissions have been implemented in each country.
　現在、火力発電所等の酸素（Ｏ２）や硫黄酸化物（ＳＯＸ）を含んだ燃焼排ガスからＣＯ２を回収する最も実用化に近い方法としては、アルカノールアミン溶液（アミン液）による吸収方法が挙げられ、１９９０年代から盛んに検討されている（特許文献１参照）。かかる方法においては、吸収塔において前記アミン液を前記燃焼排ガスと接触せしめ、ガス中のＣＯ２を液中に吸収させる。そして、かかる液（ＣＯ２リッチ吸収液）を再生塔に搬送して加熱することにより、液中からＣＯ２を遊離している。これに関し、再生塔においてＣＯ２を回収するための熱源としては、通常、水蒸気が用いられており、該水蒸気による吸収液の間接加熱が行われている。具体的には、蒸留塔でも使用されるリボイラと呼ばれる装置が用いられている（非特許文献１参照）。また、一般的に、再生塔の吸収液加熱用水蒸気は燃焼装置の熱により発生させた水蒸気の一部であるため、燃焼装置の熱効率を高めるには、ＣＯ２回収装置の蒸気使用量を出来る限り低減する必要がある。そこで、従来、液－液熱交換器により、吸収塔から再生塔に搬送される吸収液は再生塔から吸収塔に搬送される吸収液（ＣＯ２リーン吸収液）により加熱され、吸収塔へ搬送するＣＯ２リーン吸収液は冷却されていた（非特許文献２参照）。しかしながら、液－液熱交換器だけでは通常、熱交換が不十分であり、例えば、特許文献２に開示されているように、再生塔から吸収塔へ搬送される吸収液温度をさらに低減する必要がある場合も存在する。 At present, the most practical method for recovering CO 2 from combustion exhaust gas containing oxygen (O 2 ) and sulfur oxide (SO X ) in a thermal power plant is an absorption method using an alkanolamine solution (amine liquid). Have been actively studied since the 1990s (see Patent Document 1). In this method, the amine liquid is brought into contact with the combustion exhaust gas in an absorption tower to absorb CO 2 in the gas into the liquid. Then, by heating to transport such liquid (CO 2 rich absorbing solution) to the regenerator, and liberate CO 2 from the liquid. In this regard, steam is usually used as a heat source for recovering CO 2 in the regeneration tower, and the absorption liquid is indirectly heated by the steam. Specifically, an apparatus called a reboiler that is also used in a distillation column is used (see Non-Patent Document 1). In general, the steam for heating the absorption liquid in the regeneration tower is a part of the steam generated by the heat of the combustion device, so that the steam consumption of the CO 2 recovery device can be increased in order to increase the thermal efficiency of the combustion device. It is necessary to reduce as much as possible. Therefore, conventionally, the absorption liquid conveyed from the absorption tower to the regeneration tower by the liquid-liquid heat exchanger is heated by the absorption liquid (CO 2 lean absorption liquid) conveyed from the regeneration tower to the absorption tower, and conveyed to the absorption tower. The CO 2 lean absorption liquid to be cooled was cooled (see Non-Patent Document 2). However, the liquid-liquid heat exchanger alone usually does not provide sufficient heat exchange. For example, as disclosed in Patent Document 2, it is necessary to further reduce the temperature of the absorption liquid conveyed from the regeneration tower to the absorption tower. There is also a case.
　一方、再生塔に供給する蒸気量を低減するため、再生塔から吸収塔に供給される比較的高温の吸収液から熱回収し、蒸気を生成させる方法が提案されている（特許文献２及び３参照）。これらはいずれも、蒸気再圧縮法（Vapor Recompression：以下、ＶＲ法という）と呼ばれる方法である。ＶＲ法は、フラッシャと呼ばれる容器に前記吸収液を吹き、急激に減圧することにより、液のもつ潜熱分の熱エネルギを蒸気の発生に転用し、発生した吸収液の蒸気をコンプレッサで加圧・高温化し、再生塔の加熱に使用するものである。したがって、例えば、ＶＲ法による生成蒸気の温度がリボイラからの再生塔加熱用蒸気と等温であれば、ＶＲ法による生成蒸気量相当分の再生塔加熱用蒸気を低減することができる。その結果、コンプレッサの動力分のロスを考慮する必要はあるが、リボイラに供給する水蒸気供給量が低減可能になるという優れた作用効果を奏する。さらに、ＶＲ法を用いた場合、フラッシュした後の吸収液は、当然のことながら、ＶＲ処理前の吸収液温度よりも低下する。例えば、特許文献２に開示の図２と図４を比較すれば明らかである。したがって、従来と同じ再生塔の運転条件であれば、再生塔から吸収塔に搬送される吸収液を低温化でき、吸収塔内の吸収液温度も低下する。この結果、吸収液の蒸発飛散量の低減や吸収塔に搬送する吸収液の冷却機構の簡略化が可能となる。 On the other hand, in order to reduce the amount of steam supplied to the regeneration tower, methods have been proposed in which heat is recovered from a relatively high-temperature absorbent supplied from the regeneration tower to the absorption tower to generate steam (Patent Documents 2 and 3). reference). Each of these is a method called a vapor recompression method (hereinafter referred to as a VR method). In the VR method, the absorption liquid is blown into a container called a flasher and the pressure is rapidly reduced to divert the heat energy of the latent heat of the liquid to generation of steam. The temperature is raised and used for heating the regeneration tower. Therefore, for example, if the temperature of the generated steam by the VR method is isothermal with the steam for heating the regeneration tower from the reboiler, the steam for heating the regeneration tower corresponding to the amount of the generated steam by the VR method can be reduced. As a result, although it is necessary to consider the loss of the motive power of the compressor, there is an excellent effect that the amount of water vapor supplied to the reboiler can be reduced. Furthermore, when the VR method is used, the absorption liquid after flushing naturally falls below the absorption liquid temperature before the VR treatment. For example, it is clear if FIG. 2 and FIG. 4 disclosed in Patent Document 2 are compared. Therefore, if the operating conditions of the regeneration tower are the same as those in the prior art, the absorption liquid conveyed from the regeneration tower to the absorption tower can be lowered in temperature, and the absorption liquid temperature in the absorption tower is also lowered. As a result, it is possible to reduce the evaporation scattering amount of the absorbing liquid and to simplify the cooling mechanism for the absorbing liquid conveyed to the absorption tower.
　しかしながら、吸収塔から再生塔に搬送される吸収液の温度は低下するため、ＶＲ法を用いない場合と同じ条件で再生塔を運転する場合、該再生塔へ供給する水蒸気の高温化（別の捉え方をすれば、高圧力化）、もしくは、再生塔に搬送する吸収液の予熱が必要となる。したがって、この場合には、水蒸気を高温化させるためには燃焼器からの水蒸気の抜出条件を変更する必要がある。一方、既に、特許文献４に開示されているように、再生塔の加熱用蒸気から生じたスチーム凝縮水により、熱交換器で加熱されたＣＯ２リッチ吸収液をさらに加熱する方法が提案されている。この方法は、従来、顧みられなかったスチーム凝縮水を吸収液の予熱に使用するという点で優れている。しかしながら、通常、スチーム凝縮水の温度は、加熱用蒸気温度に近い高温となっている。このため、かかる方法においてＣＯ２リッチ吸収液の液温度を適温に制御するには、スチーム凝縮水の流量制御を高精度に調整する必要がある。加えて、化学吸収法では、ＣＯ２リッチ吸収液は液温度が高くなるほどＣＯ２ガスを遊離しやすくなる（非特許文献３参照）ので、高温の液との接触面でＣＯ２ガスが急激に放出されるフラッシングを引き起こす可能性もあり、装置の実運用性に問題があった。 However, since the temperature of the absorption liquid transported from the absorption tower to the regeneration tower decreases, when the regeneration tower is operated under the same conditions as when the VR method is not used, the temperature of steam supplied to the regeneration tower is If grasped, it is necessary to increase the pressure) or to preheat the absorption liquid conveyed to the regeneration tower. Therefore, in this case, in order to increase the temperature of the water vapor, it is necessary to change the conditions for extracting the water vapor from the combustor. On the other hand, as already disclosed in Patent Document 4, there has been proposed a method of further heating the CO 2 rich absorbent heated in the heat exchanger with steam condensate generated from the steam for heating the regeneration tower. Yes. This method is excellent in that steam condensate, which has not been considered in the past, is used for preheating the absorbent. However, the temperature of the steam condensate is usually a high temperature close to the heating steam temperature. For this reason, in order to control the liquid temperature of the CO 2 rich absorbent to an appropriate temperature in such a method, it is necessary to adjust the flow rate control of the steam condensed water with high accuracy. In addition, in the chemical absorption method, the CO 2 -rich absorbing liquid is more likely to liberate CO 2 gas as the liquid temperature becomes higher (see Non-Patent Document 3), so that the CO 2 gas rapidly increases at the contact surface with the high-temperature liquid. There is a possibility of causing flushing to be released, and there is a problem in actual operability of the apparatus.
特許第３５２９８５５号公報Japanese Patent No. 3529855 特開２０１２－１１５７７９号公報JP 2012-115777 A 特表２００９－５１９８２８号公報Special table 2009-519828 特開２０１１－６２７００号公報JP 2011-62700 A
　本発明はこれを踏まえてなされたものであり、その解決しようとする課題は、二酸化炭素の回収装置及びその運転方法において、再生塔から吸収塔に搬送される吸収液を加熱して液温度を上昇させることと、水蒸気供給条件を変更せずに再生塔への水蒸気供給量を低減させることとを同時に実現する点にある。 The present invention has been made on the basis of this, and the problem to be solved is that, in the carbon dioxide recovery apparatus and the operation method thereof, the absorption liquid conveyed from the regeneration tower to the absorption tower is heated to adjust the liquid temperature. It is in the point which implement | achieves raising simultaneously and reducing the water vapor | steam supply amount to a regeneration tower, without changing water vapor | steam supply conditions.
　上記課題を解決するため、本発明は、二酸化炭素を含む燃焼排ガスと、水及びアルカノールアミンを含む吸収液とを接触させて、前記二酸化炭素を前記吸収液に吸収させる吸収塔と、前記二酸化炭素を吸収した吸収液を加熱して、前記吸収液から前記二酸化炭素を遊離させて回収して前記吸収液を再生する再生塔と、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を、前記二酸化炭素を遊離させて前記再生塔から前記吸収塔に搬送される吸収液で加熱する第１熱交換器を備えてなる二酸化炭素の回収装置において、前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、大気圧よりも高圧の一次水蒸気により加熱して前記再生塔に戻す第２熱交換器と、前記第２熱交換器で前記一次水蒸気が凝縮した一次熱水を抜き出して、前記一次水蒸気よりも低圧に調整された容器内に放出させて二次熱水と二次水蒸気を生成する第１フラッシュ容器と、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を前記二次熱水で加熱する第３熱交換器と、前記二次水蒸気を加圧して前記第２熱交換器の前記一次水蒸気に合流させる第１圧縮機とを有してなることを特徴とする。 In order to solve the above problems, the present invention is directed to contacting a combustion exhaust gas containing carbon dioxide with an absorption liquid containing water and alkanolamine, and absorbing the carbon dioxide into the absorption liquid, and the carbon dioxide The absorption liquid that has absorbed the water is heated, the carbon dioxide is liberated from the absorption liquid and recovered to regenerate the absorption liquid, and the carbon dioxide is absorbed and transported from the absorption tower to the regeneration tower In the carbon dioxide recovery device comprising a first heat exchanger that liberates the carbon dioxide and heats it with the absorbent transported from the regeneration tower to the absorption tower. A second heat exchanger for extracting the absorbed liquid from the regeneration tower and heating it with primary steam higher than atmospheric pressure and returning it to the regeneration tower; and the primary heat steam condensed by the second heat exchanger. A hot water is extracted and discharged into a container adjusted to a pressure lower than that of the primary steam to generate secondary hot water and secondary steam, and the carbon dioxide is absorbed from the absorption tower. A third heat exchanger that heats the absorbent transported to the regeneration tower with the secondary hot water, and a first compressor that pressurizes the secondary steam and joins the primary steam of the second heat exchanger It is characterized by having.
　また、本発明は、前記回収装置において、前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、大気圧よりも高圧の一次水蒸気により加熱して前記再生塔に戻し、前記一次水蒸気を凝縮して生成した一次熱水から前記一次熱水よりも低温の二次熱水と前記一次水蒸気よりも低圧の二次水蒸気を生成し、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を前記二次熱水で加熱し、前記二次水蒸気を加圧して前記一次水蒸気に合流させることを特徴とする運転方法とするものである。 Further, the present invention provides the recovery apparatus, wherein the absorption liquid liberated the carbon dioxide is extracted from the regeneration tower, heated with primary steam higher than atmospheric pressure and returned to the regeneration tower, and the primary steam is recovered. The secondary hot water having a temperature lower than that of the primary hot water and the secondary steam having a pressure lower than that of the primary steam are generated from the primary hot water generated by condensation, and the carbon dioxide is absorbed to generate the regeneration tower from the absorption tower. The absorption liquid conveyed to the tank is heated with the secondary hot water, and the secondary steam is pressurized to join the primary steam.
　なお、前記二酸化炭素の回収装置の構成に加えて、前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、前記再生塔よりも低圧に調整された容器内に放出させて前記再生塔から抜き出した吸収液よりも低温の吸収液蒸気と吸収液を生成する第２フラッシュ容器と、前記低温の吸収液蒸気を加圧して前記再生塔に戻す第２圧縮機とを有し、前記低温の吸収液は、前記第１熱交換器に供給されて、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を加熱する装置構成であってもよい。 In addition to the configuration of the carbon dioxide recovery device, the absorption liquid from which the carbon dioxide has been liberated is withdrawn from the regeneration tower and released into a container adjusted to a pressure lower than that of the regeneration tower. A second flash vessel for generating absorption liquid vapor and absorption liquid having a temperature lower than that of the absorption liquid extracted from the liquid, and a second compressor for pressurizing the low-temperature absorption liquid vapor and returning it to the regeneration tower. The absorption liquid may be supplied to the first heat exchanger to absorb the carbon dioxide and heat the absorption liquid conveyed from the absorption tower to the regeneration tower.
　かかる装置構成においては、前記運転方法に加えて、前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、前記再生塔から抜き出した吸収液よりも低温の吸収液蒸気と吸収液を生成し、前記低温の吸収液蒸気を加圧して前記再生塔に戻し、前記低温の吸収液を前記熱交換器に供給して、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を加熱するものであればよい。 In such an apparatus configuration, in addition to the operation method, the absorption liquid liberated the carbon dioxide is extracted from the regeneration tower to generate absorption liquid vapor and absorption liquid at a temperature lower than that of the absorption liquid extracted from the regeneration tower. And pressurizing the low-temperature absorption liquid vapor to return to the regeneration tower, supplying the low-temperature absorption liquid to the heat exchanger, absorbing the carbon dioxide, and transporting the carbon dioxide from the absorption tower to the regeneration tower. What is necessary is just to heat the absorbing liquid.
　本発明によれば、二酸化炭素の回収装置及びその運転方法において、再生塔から吸収塔に搬送される吸収液を加熱して液温度を上昇させることと、水蒸気供給条件を変更せずに再生塔への水蒸気供給量を低減させることとを同時に実現することができる。すなわち、本発明によれば、リッチ吸収液（二酸化炭素を吸収して吸収塔から再生塔に搬送される吸収液）の温度を従来の方法よりも広い範囲で調整可能なので、再生塔に供給する水蒸気供給量を低減しながら、リーン吸収液（二酸化炭素を遊離させて再生塔から吸収塔に搬送される吸収液）のＣＯ２ローディング（ＣＯ２／アミンのモル比）を低減することも可能となる。 According to the present invention, in the carbon dioxide recovery apparatus and the operation method thereof, the absorption liquid conveyed from the regeneration tower to the absorption tower is heated to raise the liquid temperature, and the regeneration tower without changing the water vapor supply conditions. It is possible to simultaneously reduce the amount of water vapor supplied to the water. That is, according to the present invention, the temperature of the rich absorption liquid (the absorption liquid that absorbs carbon dioxide and is transported from the absorption tower to the regeneration tower) can be adjusted in a wider range than the conventional method, and is supplied to the regeneration tower. It is also possible to reduce the CO 2 loading (CO 2 / amine molar ratio) of the lean absorption liquid (the absorption liquid that liberates carbon dioxide and is transported from the regeneration tower to the absorption tower) while reducing the amount of water vapor supplied. Become.
本発明の第１の実施形態に係る二酸化炭素の回収装置の処理系統を示す概略図である。It is the schematic which shows the processing system | strain of the carbon dioxide recovery apparatus which concerns on the 1st Embodiment of this invention. 本発明の第２の実施形態に係る二酸化炭素の回収装置の処理系統を示す概略図である。It is the schematic which shows the processing system | strain of the carbon dioxide recovery apparatus which concerns on the 2nd Embodiment of this invention. 従来の二酸化炭素の回収装置における処理系統の一例を示す概略図である。It is the schematic which shows an example of the processing system in the collection | recovery apparatus of the conventional carbon dioxide. 従来の二酸化炭素の回収装置における処理系統の別例を示す概略図である。It is the schematic which shows another example of the processing system | strain in the conventional carbon dioxide collection | recovery apparatus. 図１及び図２に示す第１の実施形態及び第２の実施形態に係る二酸化炭素の回収装置、図３及び図４に示す従来の二酸化炭素の回収装置における装置性能を比較する実験の結果を示す図である。FIG. 1 and FIG. 2 show the results of experiments comparing the device performance of the carbon dioxide recovery device according to the first and second embodiments and the conventional carbon dioxide recovery device shown in FIG. 3 and FIG. FIG.
　以下、本発明の二酸化炭素（以下、ＣＯ２という）の回収装置及び該回収装置の運転方法について、添付図面を参照して説明する。図１及び図２は、本発明に係るＣＯ２の回収装置の処理系統を示す概略図であり、図１は、第１の実施形態の処理系統図、図２は、第２の実施形態の処理系統図である。図３及び図４は、従来におけるＣＯ２の回収装置の処理系統を示す概略図であり、図３は、従来の処理系統の一例を示す図、図４は、従来の処理系統の別例を示す図である。なお、各図において、同一もしくは類似する構成部材には同一の符号を付している。 Hereinafter, a carbon dioxide (hereinafter referred to as CO 2 ) recovery apparatus and an operation method of the recovery apparatus according to the present invention will be described with reference to the accompanying drawings. 1 and 2 are schematic diagrams showing a processing system of a CO 2 recovery apparatus according to the present invention, FIG. 1 is a processing system diagram of the first embodiment, and FIG. 2 is a diagram of the second embodiment. It is a processing system diagram. 3 and 4 are schematic views showing a processing system of a conventional CO 2 recovery apparatus, FIG. 3 is a diagram showing an example of a conventional processing system, and FIG. 4 is another example of a conventional processing system. FIG. In each figure, the same or similar components are denoted by the same reference numerals.
　（第１の実施形態）
　図１に示すように、本実施形態に係るＣＯ２の回収装置（以下、回収装置もしくは装置という）は、ＣＯ２を含む燃焼排ガス１と、水及びアルカノールアミンを含む吸収液とを接触させて、ＣＯ２を前記吸収液に吸収させる吸収塔７と、前記ＣＯ２を吸収した吸収液（以下、リッチ吸収液という）９を加熱して、リッチ吸収液９からＣＯ２を遊離させて回収して該リッチ吸収液９を再生する再生塔１０と、ＣＯ２を吸収して吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）を、ＣＯ２を遊離させて再生塔８から吸収塔７に搬送される吸収液（以下、リーン吸収液という）１０で加熱する第１熱交換器３を備えて構成される。この場合、回収装置は、吸収塔７でＣＯ２を吸収した吸収液（リッチ吸収液９）の少なくとも一部を再生塔８に搬送し、再生塔８でＣＯ２を遊離した吸収液（リーン吸収液１０）の少なくとも一部を吸収塔７にＣＯ２の吸収液、すなわち、水及びアルカノールアミンを含む吸収液として搬送している。その際、吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）と再生塔８から吸収塔７に搬送される吸収液（リーン吸収液１０）とを熱交換させ、リッチ吸収液９を加熱するとともに、リーン吸収液１０を冷却する構造となっている。 (First embodiment)
As shown in FIG. 1, a CO 2 recovery device (hereinafter referred to as a recovery device or device) according to the present embodiment brings a combustion exhaust gas 1 containing CO 2 into contact with an absorption liquid containing water and alkanolamine. , and the absorption tower 7 to absorb CO 2 in the absorbent liquid, the absorbent having absorbed CO 2 (hereinafter, the rich absorbent solution that) heating 9, collected and to liberate CO 2 from the rich absorbing liquid 9 Te play the rich absorbing liquid 9 regenerator 10 and the absorption liquid which is conveyed to the regenerator 8 CO 2 from the absorption tower 7 to absorb (rich absorbing fluid 9) and to release the CO 2 regeneration tower 8 The first heat exchanger 3 is configured to be heated with an absorption liquid (hereinafter referred to as a lean absorption liquid) 10 conveyed to the absorption tower 7. In this case, the recovery device transports at least a part of the absorption liquid (rich absorption liquid 9) that has absorbed CO 2 by the absorption tower 7 to the regeneration tower 8, and absorbs the CO 2 by the regeneration tower 8 (lean absorption). At least a part of the liquid 10) is conveyed to the absorption tower 7 as a CO 2 absorbing liquid, that is, an absorbing liquid containing water and alkanolamine. At that time, the absorption liquid (rich absorption liquid 9) conveyed from the absorption tower 7 to the regeneration tower 8 and the absorption liquid (lean absorption liquid 10) conveyed from the regeneration tower 8 to the absorption tower 7 are subjected to heat exchange, thereby performing rich absorption. The liquid 9 is heated and the lean absorbing liquid 10 is cooled.
　そして、回収装置は、ＣＯ２を遊離させた吸収液（リーン吸収液１０）を再生塔８から抜き出して、大気圧よりも高圧の一次水蒸気（以下、リボイラ用水蒸気という）３４により加熱して再生塔８に戻す第２熱交換器（以下、リボイラという）２１と、リボリラ２１でリボイラ用水蒸気３４が凝縮した一次熱水３５を抜き出して、リボイラ用水蒸気３４よりも低圧に調整された容器内に放出させて二次熱水３７と二次水蒸気（以下、フラッシュ水蒸気という）３９を生成する第１フラッシュ容器（以下、第１フラッシュタンクという）３２ａと、ＣＯ２を吸収して吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）を二次熱水３７で加熱する第３熱交換器３６と、フラッシュ水蒸気３９を加圧してリボイラ２１のリボイラ用水蒸気３４に合流させる第１圧縮機３３ａとを有して構成されている。 Then, the recovery device extracts the absorption liquid (lean absorption liquid 10) from which CO 2 has been released from the regeneration tower 8 and heats it with primary steam (hereinafter referred to as reboiler steam) 34 higher than atmospheric pressure to regenerate. A second heat exchanger (hereinafter referred to as a reboiler) 21 returning to the tower 8 and a primary hot water 35 in which the reboiler steam 34 has been condensed by the reboiler 21 are extracted and placed in a container adjusted to a lower pressure than the reboiler steam 34. A first flash container (hereinafter referred to as a first flash tank) 32a that generates secondary hot water 37 and secondary steam (hereinafter referred to as flash steam) 39 by discharging and CO 2 is absorbed and regenerated from the absorption tower 7 A third heat exchanger 36 that heats the absorbent (rich absorbent 9) conveyed to the tower 8 with secondary hot water 37, and pressurizes the flash steam 39 to reboiler steaming of the reboiler 21. It is configured to include a first compressor 33a which join the 34.
　つまり、回収装置は、再生塔８から吸収塔７に搬送されるリーン吸収液１０と接触する管又は容器の内部を大気圧より高圧のリボイラ用水蒸気３４が通過することにより、リーン吸収液１０を加熱する機構（以下、第１の機構という）と、前記管又は容器内でリボイラ用水蒸気３４から生成された一次熱水３５をリボイラ用水蒸気３４よりも低圧に調整された第１フラッシュタンク３２ａに供給してフラッシュ蒸発せしめるとともに、一次熱水３５より低温のフラッシュ水蒸気３９と二次熱水３７に分離せしめ、二次熱水３７により、吸収塔７から再生塔８に搬送されるリッチ吸収液９を加熱する機構（以下、第２の機構という）と、フラッシュ水蒸気３９を加圧し、リーン吸収液１０と接触する管又は容器の中に加圧されたフラッシュ水蒸気３９を通過させる機構（以下、第３の機構という）を有している。 That is, the recovery device allows the reboiler water vapor 34 having a pressure higher than the atmospheric pressure to pass through the inside of the pipe or container that is in contact with the lean absorbent 10 conveyed from the regeneration tower 8 to the absorption tower 7. A heating mechanism (hereinafter referred to as a first mechanism), and a primary hot water 35 generated from the reboiler steam 34 in the pipe or container are supplied to the first flash tank 32a adjusted to a pressure lower than that of the reboiler steam 34. While being supplied and flash-evaporated, it is separated into flash steam 39 and secondary hot water 37 having a temperature lower than that of the primary hot water 35, and the rich absorbent 9 transported from the absorption tower 7 to the regeneration tower 8 by the secondary hot water 37. A mechanism (hereinafter referred to as a second mechanism) that heats the water vapor, and the flash water 39 is pressurized into a tube or container that pressurizes the flash water vapor 39 and contacts the lean absorbent 10. Mechanism for passing the gas 39 (hereinafter, referred to as a third mechanism) have.
　換言すれば、かかる回収装置の運転方法は、ＣＯ２を遊離させた吸収液（リーン吸収液１０）を再生塔８から抜き出して、大気圧よりも高圧のリボイラ用水蒸気３４により加熱して再生塔８に戻し、リボイラ用水蒸気３４を凝縮して生成した一次熱水３５から一次熱水３５よりも低温の二次熱水３７とリボイラ用水蒸気３４よりも低圧のフラッシュ水蒸気３９を生成し、ＣＯ２を吸収して吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）を二次熱水３７で加熱し、フラッシュ水蒸気３９を加圧してリボイラ用水蒸気３４に合流させることとなっている。 In other words, the operation method of such a recovery apparatus is that the absorption liquid liberated from CO 2 (lean absorption liquid 10) is extracted from the regeneration tower 8 and heated by the reboiler steam 34 having a pressure higher than the atmospheric pressure. 8 back, to generate a low-temperature secondary heat water 37 and the low pressure flash steam 39 than reboiler for vapor 34 than the primary heat water 35 from primary heat water 35 produced by condensing a reboiler for vapor 34, CO 2 The absorption liquid (rich absorption liquid 9) conveyed from the absorption tower 7 to the regeneration tower 8 is heated with the secondary hot water 37, and the flash water vapor 39 is pressurized and merged with the reboiler water vapor 34. ing.
　ここで、図１に示す本実施形態に係る回収装置の基本的な構成について説明する。なお、説明にあたっては、かかる基本的な構成を含む回収装置の一例として、図３に示す従来装置の処理系統も併せて参照する。図３に示す回収装置において、燃焼排ガス１は、送風機２２で吸収塔７に供給される。その際、再生塔８でＣＯ２を遊離したリーン吸収液１０は、第１熱交換器３で冷却された後、ポンプ１４ａで吸引されてクーラー５ａによりさらに冷却され、吸収塔７に搬送されている。吸収塔７に搬送されたリーン吸収液１０は、充填層１１ａを通過する際、燃焼排ガス１と接触して該燃焼排ガス１からＣＯ２を吸収し、ＣＯ２を豊富に含む吸収液（リッチ吸収液）９として、吸収塔７の下部タンク３０に補集される。この場合、吸収塔７には、上下方向の中間部にＣＯ２吸収部が設けられている。ＣＯ２吸収部は、リーン吸収液１０を噴霧する吸収液スプレー部１３と、吸収液スプレー部１３から噴霧されたリーン吸収液１０と燃焼排ガス１を接触させ、燃焼排ガス１からＣＯ２を除去・回収する充填層１１ａを有して構成されている。燃焼排ガス１は、吸収塔７の充填層１１ａを上昇する間に、充填層１１ａの上部から流下するリーン吸収液１０と接触してＣＯ２が除去される。換言すれば、リーン吸収液１０は、燃焼排ガス１と接触して該燃焼排ガス１に含まれるＣＯ２を吸収する。 Here, the basic configuration of the recovery apparatus according to the present embodiment shown in FIG. 1 will be described. In the description, the processing system of the conventional apparatus shown in FIG. 3 is also referred to as an example of the recovery apparatus including the basic configuration. In the recovery device shown in FIG. 3, the combustion exhaust gas 1 is supplied to the absorption tower 7 by a blower 22. At that time, the lean absorbent 10 that has liberated CO 2 in the regeneration tower 8 is cooled by the first heat exchanger 3, sucked by the pump 14 a, further cooled by the cooler 5 a, and conveyed to the absorption tower 7. Yes. When the lean absorbing liquid 10 conveyed to the absorption tower 7 passes through the packed bed 11a, the lean absorbing liquid 10 comes into contact with the combustion exhaust gas 1 to absorb CO 2 from the combustion exhaust gas 1, and absorbs rich CO 2 (rich absorption). Liquid 9) is collected in the lower tank 30 of the absorption tower 7. In this case, the absorption tower 7 is provided with a CO 2 absorption section at an intermediate portion in the vertical direction. The CO 2 absorption section removes CO 2 from the combustion exhaust gas 1 by bringing the absorption liquid spray section 13 to spray the lean absorption liquid 10 into contact with the lean absorption liquid 10 sprayed from the absorption liquid spray section 13 and the combustion exhaust gas 1. It has a packed bed 11a to be recovered. While the combustion exhaust gas 1 ascends the packed bed 11a of the absorption tower 7, it comes into contact with the lean absorbent 10 flowing down from the upper part of the packed bed 11a to remove CO 2 . In other words, the lean absorbent 10 comes into contact with the combustion exhaust gas 1 and absorbs CO 2 contained in the combustion exhaust gas 1.
　燃焼排ガス１からＣＯ２が除去された後の排ガス１６は、ＣＯ２吸収部の上部に設けられた水洗部２３でミスト及び蒸気状アミンが捕集されて冷却される。なお、水洗部２３は、ＣＯ２除去後の排ガス１６に洗浄水１７を噴霧する水スプレー部１２、洗浄水１７を貯留するコレクタ１８、洗浄水１７を冷却するクーラー５ｂ、洗浄水１７を循環させるポンプ１４ｂを有して構成されている。そして、水洗部２３で蒸気状アミンの除去及び冷却されたＣＯ２除去後の排ガス１６は、吸収塔７の上部に設けられた充填層１１ｂでミストが回収された後、例えば、大気中に放出される。 After the CO 2 is removed from the combustion exhaust gas 1, the mist and vaporous amine are collected and cooled in the water washing part 23 provided at the upper part of the CO 2 absorption part. In addition, the water washing part 23 circulates the water spray part 12 which sprays the washing water 17 on the exhaust gas 16 after CO 2 removal, the collector 18 which stores the washing water 17, the cooler 5b which cools the washing water 17, and the washing water 17. It has a pump 14b. The exhaust gas 16 after the removal of vaporous amine and cooled CO 2 by the water washing section 23 is released into the atmosphere, for example, after the mist is collected in the packed bed 11b provided in the upper part of the absorption tower 7. Is done.
　吸収塔７の下部タンク３０に補集されたリッチ吸収液９は、第１熱交換器３で加熱された後、再生塔８に搬送され、充填層１１ｃを通過中にリボイラ２１で発生した蒸気４２により加熱され、ＣＯ２が遊離される。この場合、再生塔８には、上下方向の中間部にＣＯ２遊離部が設けられている。ＣＯ２遊離部は、リッチ吸収液９を噴霧する吸収液スプレー部１５と、吸収液スプレー部１５から噴霧されたリッチ吸収液９と再生塔８の下部から上昇する蒸気（リーン吸収液１０の蒸気）とを気液接触させ、リッチ吸収液９からＣＯ２を遊離させる充填層１１ｃを有して構成されている。また、ＣＯ２遊離部の上部には、還流水１９を噴霧する水洗スプレー部２６と、ＣＯ２遊離部により遊離されたＣＯ２からミストを捕集する充填層（デミスタ）１１ｄが設けられている。 The rich absorbent 9 collected in the lower tank 30 of the absorption tower 7 is heated by the first heat exchanger 3 and then transported to the regeneration tower 8 to generate steam generated by the reboiler 21 while passing through the packed bed 11c. Heated by 42 liberates CO 2 . In this case, the regeneration tower 8 is provided with a CO 2 liberation part in the middle part in the vertical direction. The CO 2 liberating part includes an absorbing liquid spraying part 15 for spraying the rich absorbing liquid 9, a rich absorbing liquid 9 sprayed from the absorbing liquid spraying part 15, and a vapor rising from the lower part of the regeneration tower 8 (steam of the lean absorbing liquid 10). ) Are in gas-liquid contact with each other to have a packed bed 11c that liberates CO 2 from the rich absorbent 9. Further, on the upper part of the CO 2 releasing part, a water washing spray part 26 for spraying the reflux water 19 and a packed bed (demister) 11d for collecting mist from the CO 2 released by the CO 2 releasing part are provided. .
　ＣＯ２遊離部により遊離されたＣＯ２は、充填層（デミスタ）１１ｄを通過する際にミストが捕集され、再生塔８の上部からＣＯ２ガスとして回収される。再生塔８から排出されたＣＯ２ガスは、クーラー（ガス冷却器）５ｃで冷却された後、ＣＯ２分離器２０でＣＯ２ガス２７と還流水１９に分離される。分離された還流水１９は、ポンプ１４ｃによって昇圧され、水洗スプレー部２６に供給される。なお、分離されたＣＯ２ガス２７は、例えば、図示しない液化設備等へ送出される。 CO 2 liberated by CO 2 free portion, the mist is captured when passing through a packed bed (demister) 11d, is recovered as CO 2 gas from the top of the regenerator 8. The CO 2 gas discharged from the regeneration tower 8 is cooled by a cooler (gas cooler) 5 c and then separated into a CO 2 gas 27 and a reflux water 19 by a CO 2 separator 20. The separated reflux water 19 is pressurized by the pump 14 c and supplied to the water washing spray unit 26. The separated CO 2 gas 27 is sent to, for example, a liquefaction facility (not shown).
　一方、ＣＯ２遊離後の吸収液（リーン吸収液）１０は、再生塔８の下部タンク３１で回収される。回収されたリーン吸収液１０は、リボイラ２１に送液されて加熱される。リボイラ用水蒸気３４が凝縮した一次熱水３５の一部又は全部は、気水分離器４０によりリボイラ用水蒸気３４と分離熱水４３に分離される。分離されたリボイラ用水蒸気３４は、リボイラ２１の加熱用に供給される。この場合、リボイラ用水蒸気３４は、大気圧より高圧に調整されており、リボイラ２１は、管又は容器の内部をリボイラ用水蒸気３４が通過することにより、リーン吸収液１０を加熱している。すなわち、リボイラ２１は、第１の機構に相当する。これに対し、分離熱水４３は、第３熱交換器３６に供給され、リッチ吸収液９を加熱するために用いられる。また、ＣＯ２遊離後の吸収液（リーン吸収液１０）は、第１熱交換器３においてリッチ吸収液９との熱交換により冷却され、ポンプ１４ａで吸収塔７に搬送されている。その際、リッチ吸収液９は、第１熱交換器３においてリーン吸収液１０から吸熱し、加熱される。これにより、リーン吸収液１０（別の捉え方をすれば、リッチ吸収液９）は、燃焼排ガス１からＣＯ２を吸収するための吸収液（水及びアルカノールアミンを含む吸収液）として再生される。 On the other hand, the absorbing solution (lean absorbing solution) 10 after the liberation of CO 2 is collected in the lower tank 31 of the regeneration tower 8. The collected lean absorbent 10 is sent to the reboiler 21 and heated. Part or all of the primary hot water 35 in which the reboiler steam 34 is condensed is separated into the reboiler steam 34 and the separated hot water 43 by the steam separator 40. The separated reboiler steam 34 is supplied for heating the reboiler 21. In this case, the reboiler water vapor 34 is adjusted to a pressure higher than the atmospheric pressure, and the reboiler 21 heats the lean absorbent 10 by the reboiler water vapor 34 passing through the inside of the tube or the container. That is, the reboiler 21 corresponds to a first mechanism. On the other hand, the separated hot water 43 is supplied to the third heat exchanger 36 and used to heat the rich absorbent 9. In addition, the absorption liquid (lean absorption liquid 10) after liberation of CO 2 is cooled by heat exchange with the rich absorption liquid 9 in the first heat exchanger 3, and is conveyed to the absorption tower 7 by the pump 14a. At that time, the rich absorbent 9 absorbs heat from the lean absorbent 10 in the first heat exchanger 3 and is heated. Thereby, the lean absorbent 10 (in other words, the rich absorbent 9) is regenerated as an absorbent for absorbing CO 2 from the combustion exhaust gas 1 (an absorbent containing water and alkanolamine). .
　これに対し、本発明の第１の実施形態に係る回収装置は、図１に示すように、リボイラ用水蒸気３４が凝縮した一次熱水３５の一部又は全部をＣＯ２遊離後の吸収液（リーン吸収液１０）とは別の第１フラッシュタンク３２ａに供給し、減圧してより低温化した二次熱水３７とフラッシュ水蒸気３９を第１圧縮機３３ａで加圧し、ＶＲ水蒸気３８を生成する機構を加えている。この場合、第１フラッシュタンク３２ａは、リボイラ用水蒸気３４よりも低圧に調整されているが、第１圧縮機３３ａを設けることにより、第１フラッシュタンク３２ａの内部の圧力と一次熱水３５の差圧（フラッシュ圧）を調整することを可能としている。つまり、フラッシュ圧の調整が可能となるため、フラッシュ水蒸気３９の発生量と二次熱水３７の温度をコントロールすることができる。これにより、例えば、二次熱水３７の温度を調整し、該二次熱水３７を第３熱交換器３６におけるリッチ吸収液９の過熱防止のために用いることが可能となる。すなわち、第１フラッシュタンク３２ａ及び第３熱交換器３６は、第２の機構に相当する。また、第１圧縮機３３ａからリボイラ２１へＶＲ水蒸気３８を供給することで、該ＶＲ水蒸気３８をリボイラ２１の加熱に用いることができる。すなわち、第１圧縮機３３ａは、第３の機構に相当する。これにより、リボイラ用水蒸気３４の供給量をＶＲ水蒸気３８相当量だけ低減させることも可能となる。なお、再生塔８の内部は、リッチ吸収液９ができるだけ蒸発しないように、大気圧よりも加圧した状態としておくことが望ましい。 In contrast, as shown in FIG. 1, the recovery device according to the first embodiment of the present invention uses a part or all of the primary hot water 35 condensed with the reboiler water vapor 34 as an absorption liquid after CO 2 release ( The secondary hot water 37 and the flash steam 39, which are supplied to the first flash tank 32a different from the lean absorbent 10) and depressurized to lower the temperature, are pressurized by the first compressor 33a to generate VR steam 38. The mechanism is added. In this case, the first flash tank 32a is adjusted to a pressure lower than that of the reboiler steam 34, but by providing the first compressor 33a, the difference between the pressure inside the first flash tank 32a and the primary hot water 35 is provided. It is possible to adjust the pressure (flash pressure). That is, since the flash pressure can be adjusted, the generation amount of the flash water vapor 39 and the temperature of the secondary hot water 37 can be controlled. Thereby, for example, the temperature of the secondary hot water 37 can be adjusted, and the secondary hot water 37 can be used to prevent overheating of the rich absorbent 9 in the third heat exchanger 36. That is, the first flash tank 32a and the third heat exchanger 36 correspond to a second mechanism. Further, by supplying the VR steam 38 from the first compressor 33 a to the reboiler 21, the VR steam 38 can be used for heating the reboiler 21. That is, the first compressor 33a corresponds to a third mechanism. As a result, the supply amount of the reboiler water vapor 34 can be reduced by an amount equivalent to the VR water vapor 38. In addition, it is desirable that the inside of the regeneration tower 8 is in a state where the pressure is higher than the atmospheric pressure so that the rich absorbent 9 is not evaporated as much as possible.
　（第２の実施形態）
　また、本発明の第２の実施形態に係る回収装置は、上述した第１の実施形態に係る回収装置（図１）に加えて、ＣＯ２を遊離させた吸収液（リーン吸収液１０）を再生塔８から抜き出して、再生塔８よりも低圧に調整された容器内に放出させて再生塔８から抜き出した吸収液（以下、一次リーン吸収液という）１０ａよりも低温の吸収液蒸気（以下、ＶＲ吸収液蒸気という）４１と一次リーン吸収液１０ａよりも低温の吸収液（以下、二次リーン吸収液という）１０ｂを生成する第２フラッシュ容器（以下、第２フラッシュタンクという）３２ｂと、ＶＲ吸収液蒸気４１を加圧して再生塔８に戻す第２圧縮機３３ｂとを有して構成されている。そして、かかる回収装置において、二次リーン吸収液１０ｂは、第１熱交換器３に供給されて、ＣＯ２を吸収して吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）を加熱している。 (Second Embodiment)
In addition to the recovery device (FIG. 1) according to the first embodiment described above, the recovery device according to the second embodiment of the present invention uses an absorption liquid (lean absorption liquid 10) that liberates CO 2. Absorption liquid vapor (hereinafter, referred to as a primary lean absorption liquid) 10a extracted from the regeneration tower 8 and discharged into a container adjusted to a lower pressure than the regeneration tower 8 and extracted from the regeneration tower 8 (hereinafter referred to as a primary lean absorption liquid). , VR absorption liquid vapor) 41 and a second flash container (hereinafter referred to as a second flash tank) 32b that generates an absorption liquid (hereinafter referred to as a secondary lean absorption liquid) 10b having a temperature lower than that of the primary lean absorption liquid 10a, And a second compressor 33b that pressurizes the VR absorbing liquid vapor 41 and returns it to the regeneration tower 8. In such a recovery apparatus, the secondary lean absorbent 10b is supplied to the first heat exchanger 3, absorbs CO 2 and is transported from the absorption tower 7 to the regeneration tower 8 (rich absorbent 9 ) Is heating.
　つまり、本実施形態に係る回収装置は、上述した第１の機構から第３の機構の３つの機構に加えて、再生塔８から吸収塔７に搬送される吸収液（一次リーン吸収液１０ａ）が第１熱交換器３でリッチ吸収液９と熱交換される前に、リーン吸収液１０の全部又は一部を再生塔８よりも低圧に調整された第２フラッシュタンク３２ｂに供給してフラッシュ蒸発せしめるとともに、一次リーン吸収液１０ａよりも低温のＶＲ吸収液蒸気４１と二次リーン吸収液１０ｂに分離せしめ、ＶＲ吸収液蒸気４１を加圧して再生塔８に供給する機構（以下、第４の機構という）と、吸収塔７から再生塔８へ搬送される吸収液（リッチ吸収液９）を二次リーン吸収液１０ｂにより加熱する機構（以下、第５の機構という）を有している。 That is, the recovery apparatus according to the present embodiment has an absorption liquid (primary lean absorption liquid 10a) transported from the regeneration tower 8 to the absorption tower 7 in addition to the above-described three mechanisms of the first mechanism to the third mechanism. Before the heat exchange with the rich absorbent 9 in the first heat exchanger 3, all or part of the lean absorbent 10 is supplied to the second flash tank 32 b adjusted to a lower pressure than the regeneration tower 8 and flashed. A mechanism for evaporating and separating the VR absorption liquid vapor 41 and the secondary lean absorption liquid 10b at a lower temperature than the primary lean absorption liquid 10a, pressurizing the VR absorption liquid vapor 41 and supplying it to the regeneration tower 8 (hereinafter referred to as fourth And a mechanism (hereinafter referred to as a fifth mechanism) for heating the absorption liquid (rich absorption liquid 9) conveyed from the absorption tower 7 to the regeneration tower 8 by the secondary lean absorption liquid 10b. .
　換言すれば、かかる回収装置の運転方法は、ＣＯ２を遊離させた吸収液（リーン吸収液１０）を再生塔８から抜き出して、再生塔８から抜き出した吸収液（一次リーン吸収液１０ａ）よりも低温のＶＲ吸収液蒸気４１と一次リーン吸収液１０ａよりも低温の二次リーン吸収液１０ｂを生成し、ＶＲ吸収液蒸気４１を加圧して再生塔８に戻し、二次リーン吸収液１０ｂを第１熱交換器３に供給して、ＣＯ２を吸収して吸収塔７から再生塔８に搬送される吸収液（リッチ吸収液９）を加熱することが、上述した第１の実施形態に係る回収装置（図１）の運転方法に加えられている。 In other words, the operation method of the recovery apparatus is that the absorption liquid (lean absorption liquid 10) from which CO 2 has been liberated is extracted from the regeneration tower 8, and from the absorption liquid (primary lean absorption liquid 10a) extracted from the regeneration tower 8. The low-temperature VR absorption liquid vapor 41 and the secondary lean absorption liquid 10b lower than the primary lean absorption liquid 10a are generated, the VR absorption liquid vapor 41 is pressurized and returned to the regeneration tower 8, and the secondary lean absorption liquid 10b is recovered. is supplied to the first heat exchanger 3, the absorption liquid from the absorption tower 7 to absorb the CO 2 is transported to the regenerator 8 to heat the (rich absorbing fluid 9), the first embodiment described above This is added to the operation method of the recovery device (FIG. 1).
　図２に示すように、かかる回収装置は、上述した第１の実施形態に係る回収装置（図１）に、第２フラッシュタンク３２ｂと第２圧縮機３３ｂをさらに加えた構成となっている。すなわち、本実施形態において、回収装置は、再生塔８のリーン吸収液１０を第２フラッシュタンク３２ｂに供給し、減圧することによって蒸気を発生させ、発生させた蒸気を第２圧縮機３３ｂにおいて加圧及び加熱し、再生塔８に供給する機構を備えている。かかる回収装置において、リーン吸収液１０は、第２フラッシュタンク３２ｂ内及び第１熱交換器３において液温度が低下する。また、第２フラッシュタンク３２ｂ内のリーン吸収液１０の蒸気は、第２圧縮機３３ｂで加圧及び加熱されてＶＲ吸収液蒸気４１となり、ＶＲ吸収液蒸気４１は、再生塔８に供給される。すなわち、第２フラッシュタンク３２ｂ及び第２圧縮機３３ｂは、第４の機構に相当する。再生塔８に供給されたＶＲ吸収液蒸気４１は、リボイラ２１からの蒸気４２とともに、再生塔８内の加熱に使用される。この結果、リボイラ用水蒸気３４の供給量をＶＲ吸収液蒸気４１相当量だけ、第１の実施形態（図１）よりも低減させることができる。また、第２フラッシュタンク３２ｂに供給された一次リーン吸収液１０ａをフラッシュ蒸発して得られた二次リーン吸収液１０ｂは、第１熱交換器３においてリッチ吸収液９を加熱するために用いられる。すなわち、第１熱交換器３、そして第２フラッシュタンク３２ｂ及び第２圧縮機３３ｂは、第５の機構に相当する。なお、第１の実施形態と同様に、第３熱交換器３６において、リボイラ２１からの一次熱水３５をフラッシュした二次熱水３７により、再生塔８に搬送されるリッチ吸収液９を加熱することも可能である。 As shown in FIG. 2, the recovery device has a configuration in which a second flash tank 32b and a second compressor 33b are further added to the recovery device (FIG. 1) according to the first embodiment described above. That is, in the present embodiment, the recovery device supplies the lean absorbing liquid 10 of the regeneration tower 8 to the second flash tank 32b, generates steam by reducing the pressure, and adds the generated steam to the second compressor 33b. A mechanism for supplying pressure to the regeneration tower 8 is provided. In such a recovery apparatus, the liquid temperature of the lean absorbing liquid 10 decreases in the second flash tank 32b and in the first heat exchanger 3. Further, the vapor of the lean absorbing liquid 10 in the second flash tank 32b is pressurized and heated by the second compressor 33b to become the VR absorbing liquid vapor 41, and the VR absorbing liquid vapor 41 is supplied to the regeneration tower 8. . That is, the second flash tank 32b and the second compressor 33b correspond to a fourth mechanism. The VR absorption liquid vapor 41 supplied to the regeneration tower 8 is used for heating the regeneration tower 8 together with the steam 42 from the reboiler 21. As a result, the supply amount of the reboiler water vapor 34 can be reduced by an amount corresponding to the VR absorption liquid vapor 41 compared to the first embodiment (FIG. 1). The secondary lean absorbent 10b obtained by flash evaporation of the primary lean absorbent 10a supplied to the second flash tank 32b is used to heat the rich absorbent 9 in the first heat exchanger 3. . That is, the first heat exchanger 3, the second flash tank 32b, and the second compressor 33b correspond to a fifth mechanism. As in the first embodiment, in the third heat exchanger 36, the rich absorbent 9 transported to the regeneration tower 8 is heated by the secondary hot water 37 obtained by flushing the primary hot water 35 from the reboiler 21. It is also possible to do.
　ここで、図４に示す従来におけるＣＯ２の回収装置の処理系統の別例について、本実施形態（図２）との比較において説明する。図４に示すように、かかる回収装置は、リボイラ２１からの二次熱水３７によりリッチ吸収液９を加熱する機構を備えていない。また、かかる回収装置は、フラッシュ水蒸気３９を加圧し、リボイラ２１を加熱するためのＶＲ水蒸気３８を生成する機構を備えていない。具体的には、かかる回収装置は、リッチ吸収液９の温度調整のための第３熱交換器３６を有していない。したがって、かかる回収装置においては、再生塔８に供給されるリッチ吸収液９の液温度が低下してしまう。このため、かかる回収装置において、再生塔８の出口でのリーン吸収液１０におけるＣＯ２／アミンのモル比（以下、ＣＯ２ローディングという）を本実施形態と同レベルとするには、例えば、リボイラ用水蒸気３４を高温化（別の捉え方をすれば、高圧力化）する必要が生じる。また、かかる回収装置においては、一次熱水３５からフラッシュ水蒸気３９を生成する機構も備えていないため、本実施形態よりも余計にリボイラ用水蒸気３４を供給する必要も生じる。 Here, another example of the processing system of the conventional CO 2 recovery apparatus shown in FIG. 4 will be described in comparison with the present embodiment (FIG. 2). As shown in FIG. 4, the recovery device does not include a mechanism for heating the rich absorbent 9 with the secondary hot water 37 from the reboiler 21. In addition, such a recovery device does not include a mechanism that generates the VR steam 38 for pressurizing the flash steam 39 and heating the reboiler 21. Specifically, the recovery device does not have the third heat exchanger 36 for adjusting the temperature of the rich absorbent 9. Therefore, in such a recovery apparatus, the liquid temperature of the rich absorbent 9 supplied to the regeneration tower 8 is lowered. Therefore, in such a recovery apparatus, in order to set the CO 2 / amine molar ratio (hereinafter referred to as CO 2 loading) in the lean absorbent 10 at the outlet of the regeneration tower 8 to the same level as in this embodiment, for example, a reboiler Therefore, it is necessary to increase the temperature of the water vapor 34 (in other words, increase the pressure). In addition, since such a recovery apparatus does not include a mechanism for generating the flash steam 39 from the primary hot water 35, it is necessary to supply the reboiler steam 34 more than in the present embodiment.
　以上のような本発明の第１の実施形態及び第２の実施形態に係る回収装置（図１及び図２）と従来の回収装置（図３及び図４）の装置性能について、再生塔８の出入口における液温度、及び再生塔８に供給する水蒸気の供給量を測定した実験の結果に基づいて説明する。この場合、第１の実施形態に係る回収装置（図１）を実施例１、第２の実施形態に係る回収装置（図２）を実施例２、従来の回収装置の一例（図３）を比較例１、従来の回収装置の別例（図４）を比較例２としており、各装置における実験条件は以下の通りとした。 Regarding the performance of the recovery apparatus (FIGS. 1 and 2) and the conventional recovery apparatus (FIGS. 3 and 4) according to the first and second embodiments of the present invention as described above, A description will be given based on the results of experiments in which the liquid temperature at the inlet / outlet and the amount of water vapor supplied to the regeneration tower 8 were measured. In this case, the recovery device according to the first embodiment (FIG. 1) is Example 1, the recovery device according to the second embodiment (FIG. 2) is Example 2, and an example of a conventional recovery device (FIG. 3). Comparative Example 1 and another example of the conventional recovery device (FIG. 4) are referred to as Comparative Example 2, and the experimental conditions in each device were as follows.
（実施例１）
　実験にあたっては、吸収塔７の入口における燃焼排ガス１の温度及びリーン吸収液１０の液温度を４０℃、再生塔８の内部圧力を１６０ｋＰａ(ゲージ)、再生塔８におけるリーン吸収液１０の液温度を最高１２０℃、リボイラ用水蒸気３４の温度を１４０℃、クーラー温度を３０℃、燃焼排ガス１のガス量を５００ｍ３／ｈ、液ガス比を３．０(Ｌ／ｍ３)、循環液量を１５００Ｌにそれぞれ設定した（以下、これらの設定値をまとめて、実験条件という）。 (Example 1)
In the experiment, the temperature of the combustion exhaust gas 1 and the liquid temperature of the lean absorbent 10 at the inlet of the absorption tower 7 are 40 ° C., the internal pressure of the regeneration tower 8 is 160 kPa (gauge), and the liquid temperature of the lean absorbent 10 in the regeneration tower 8. The reboiler steam 34 temperature is 140 ° C., the cooler temperature is 30 ° C., the amount of combustion exhaust gas 1 is 500 m 3 / h, the liquid gas ratio is 3.0 (L / m 3 ), the amount of circulating fluid Was set to 1500 L (hereinafter, these set values are collectively referred to as experimental conditions).
　本実施例においては、上述したように、燃焼排ガス１に含まれるＣＯ２を吸収塔７で除去し、吸収塔７の下部タンク３０内にリッチ吸収液９として捕集する。捕集したリッチ吸収液９は、第１熱交換器３で加熱した後、再生塔８に搬送する。再生塔８の内部では、リッチ吸収液９をリボイラ２１により更に加熱することでＣＯ２を遊離し、リーン吸収液１０として再生塔８の下部タンク３１に回収する。回収したリーン吸収液１０は、第１熱交換器３を経て、吸収塔７に再び搬送する。リボイラ２１から排出される一次熱水３５は、第１フラッシュタンク３２ａに供給し、得られた二次熱水３７は、第３熱交換器３６に供給する。二次熱水３７と同時に得られたフラッシュ水蒸気３９は、１４０℃となるまで第１圧縮機３３ａにより加圧した。これにより得られたＶＲ水蒸気３８は、リボイラ２１の加熱蒸気として用いた。なお、リーン吸収液１０には、３０％ＭＥＡ（モノエタノールアミン）液を用いた。また、本実施例では、リボイラ２１としてケトル型を用いたが、サーモサイフォン型のリボイラを用いることも可能である。 In the present embodiment, as described above, CO 2 contained in the combustion exhaust gas 1 is removed by the absorption tower 7 and collected as the rich absorbent 9 in the lower tank 30 of the absorption tower 7. The collected rich absorbent 9 is heated by the first heat exchanger 3 and then conveyed to the regeneration tower 8. Inside the regeneration tower 8, the rich absorbent 9 is further heated by the reboiler 21 to liberate CO 2 and recovered as a lean absorbent 10 in the lower tank 31 of the regeneration tower 8. The collected lean absorbent 10 is conveyed again to the absorption tower 7 via the first heat exchanger 3. The primary hot water 35 discharged from the reboiler 21 is supplied to the first flash tank 32a, and the obtained secondary hot water 37 is supplied to the third heat exchanger 36. The flash steam 39 obtained simultaneously with the secondary hot water 37 was pressurized by the first compressor 33a until it reached 140 ° C. The VR water vapor 38 thus obtained was used as heating steam for the reboiler 21. As the lean absorbing solution 10, a 30% MEA (monoethanolamine) solution was used. In the present embodiment, a kettle type is used as the reboiler 21, but a thermosiphon type reboiler can also be used.
（実施例２）
　図２に示すように、本実施例においては、第１熱交換器３を通過する前のリーン吸収液１０（一次リーン吸収液１０ａ）を第２フラッシュタンク３２ｂでフラッシュ蒸発させ、得られた一次リーン吸収液１０ａの蒸気を第２圧縮機３３ｂで加圧してＶＲ吸収液蒸気４１を生成する。そして、生成したＶＲ吸収液蒸気４１を再生塔８に供給するとともに、第２フラッシュタンク３２ｂ内のリーン吸収液１０（二次リーン吸収液１０ｂ）を第１熱交換器３に供給している。これ以外の装置構成及び実験条件は、上述した実施例１と同様とした。 (Example 2)
As shown in FIG. 2, in this embodiment, the lean absorbent 10 (primary lean absorbent 10a) before passing through the first heat exchanger 3 is flash-evaporated in the second flash tank 32b, and the obtained primary is obtained. The vapor of the lean absorbent 10a is pressurized by the second compressor 33b to generate the VR absorbent vapor 41. The generated VR absorption liquid vapor 41 is supplied to the regeneration tower 8, and the lean absorption liquid 10 (secondary lean absorption liquid 10 b) in the second flash tank 32 b is supplied to the first heat exchanger 3. The rest of the apparatus configuration and experimental conditions were the same as in Example 1 described above.
（比較例１）
　図３に示すように、本比較例においては、リボイラ２１から排出される一次熱水３５を気水分離器４０によりリボイラ用水蒸気３４と分離熱水４３に分離する。リボイラ用水蒸気３４は、リボイラ２１の加熱用に供給し、分離熱水４３は、吸収塔７から再生塔８に搬送されるリッチ吸収液９を加熱するために用いる。これ以外の装置構成及び実験条件は、上述した実施例１と同様とした。ただし、本比較例は、第１フラッシュタンク３２ａ及び第１圧縮機３３ａを有する装置構成とはなっていない。 (Comparative Example 1)
As shown in FIG. 3, in this comparative example, the primary hot water 35 discharged from the reboiler 21 is separated into reboiler steam 34 and separated hot water 43 by the steam separator 40. The reboiler steam 34 is supplied for heating the reboiler 21, and the separated hot water 43 is used to heat the rich absorbent 9 transported from the absorption tower 7 to the regeneration tower 8. The rest of the apparatus configuration and experimental conditions were the same as in Example 1 described above. However, this comparative example does not have an apparatus configuration including the first flash tank 32a and the first compressor 33a.
（比較例２）
　図４に示すように、本比較例においては、一次熱水３５をフラッシュ蒸発させて得られた二次熱水３７を第３熱交換器３６に供給する機構、及び二次熱水３７と同時に得られるＶＲ水蒸気３８をリボイラ２１を加熱するために供給する機構を備えていない。これ以外の装置構成及び実験条件は、上述した実施例２と同様とした。 (Comparative Example 2)
As shown in FIG. 4, in this comparative example, a mechanism for supplying secondary hot water 37 obtained by flash evaporation of the primary hot water 35 to the third heat exchanger 36, and the secondary hot water 37 simultaneously. A mechanism for supplying the obtained VR water vapor 38 to heat the reboiler 21 is not provided. Other apparatus configurations and experimental conditions were the same as those in Example 2 described above.
　図５は、上述した実施例１,２及び比較例１,２に係る各装置における実験結果を示す図である。この場合、図５には、各装置における再生塔８の入口及び出口の液温度の値を示す。また、図５には、実施例１,２及び比較例２に係る各装置における再生塔８の出口でのリーン吸収液１０中のＣＯ２濃度を、比較例１に係る装置における値を１とした場合の相対値で示している。そして、図５には、実施例１,２及び比較例２に係る各装置におけるリボイラ２１への水蒸気（リボイラ用水蒸気３４）の供給量を、比較例１に係る装置における値を１００とした場合の相対値で示している。 FIG. 5 is a diagram illustrating experimental results in the apparatuses according to Examples 1 and 2 and Comparative Examples 1 and 2 described above. In this case, FIG. 5 shows the liquid temperature values at the inlet and outlet of the regeneration tower 8 in each apparatus. FIG. 5 shows the CO 2 concentration in the lean absorbent 10 at the outlet of the regeneration tower 8 in each apparatus according to Examples 1 and 2 and Comparative Example 2, and the value in the apparatus according to Comparative Example 1 as 1. The relative value is shown. In FIG. 5, when the supply amount of water vapor (reboiler water vapor 34) to the reboiler 21 in each device according to Examples 1 and 2 and Comparative Example 2 is set to 100 in the device according to Comparative Example 1 The relative value is shown.
　図５に示すように、比較例１及び実施例１,２では、再生塔８に搬送されるリッチ吸収液（ＣＯ２リッチアミン）９を第３熱交換器３６で加熱するため、比較例２よりも再生塔８の入口におけるリッチ吸収液９の液温度が高い。なお、比較例１では、再生塔８の上部における圧力が変化する現象が見られた。これは、一次熱水３５の温度が１４０℃近い温度であるため、上述したようにリッチ吸収液９の一部からＣＯ２が遊離してフラッシュしているためと推測される。一方、実施例１では、二次熱水３７の温度が大きく低減されるため、比較例１のような現象は生じなかった。実施例２及び比較例２では、いずれもリボイラ２１へのリボイラ用水蒸気３４の供給量を比較例１よりも低減できているが、比較例２では、再生塔８の入口におけるリッチ吸収液９の液温度が低いため、及び一次熱水３５からのフラッシュ水蒸気３９を利用していないため、リボイラ用水蒸気３４の供給量は、実施例２よりも大きく、実施例１と同等であった。 As shown in FIG. 5, in Comparative Example 1 and Examples 1 and 2, the rich absorbent (CO 2 rich amine) 9 transported to the regeneration tower 8 is heated by the third heat exchanger 36, so that Comparative Example 2 The liquid temperature of the rich absorbent 9 at the inlet of the regeneration tower 8 is higher than that. In Comparative Example 1, a phenomenon in which the pressure in the upper part of the regeneration tower 8 changes was observed. This is presumably because the temperature of the primary hot water 35 is close to 140 ° C., so that CO 2 is liberated from a part of the rich absorbent 9 and flashed as described above. On the other hand, in Example 1, since the temperature of the secondary hot water 37 was greatly reduced, the phenomenon as in Comparative Example 1 did not occur. In both Example 2 and Comparative Example 2, the supply amount of the reboiler water vapor 34 to the reboiler 21 can be reduced as compared with Comparative Example 1, but in Comparative Example 2, the rich absorbent 9 at the inlet of the regeneration tower 8 is reduced. Since the liquid temperature was low and the flash water vapor 39 from the primary hot water 35 was not used, the supply amount of the reboiler water vapor 34 was larger than that in Example 2 and was equivalent to that in Example 1.
　以上、本発明の第１の実施形態（図１）及び第２の実施形態（図２）に係る二酸化炭素の回収装置及びその運転方法によれば、再生塔８から吸収塔７に搬送されるリーン吸収液１０を加熱して液温度を上昇させることと、水蒸気供給条件を変更せずに再生塔８への水蒸気供給量を低減させることとを同時に実現することができる。すなわち、本発明によれば、再生塔８に搬送するリッチ吸収液９の温度を従来の方法よりも広い範囲で調整可能なので、再生塔８に供給する水蒸気供給量を低減しながら、リーン吸収液１０のＣＯ２ローディングを低減することも可能となる。 As described above, according to the carbon dioxide recovery apparatus and the operation method thereof according to the first embodiment (FIG. 1) and the second embodiment (FIG. 2) of the present invention, the carbon dioxide is transported from the regeneration tower 8 to the absorption tower 7. It is possible to simultaneously increase the liquid temperature by heating the lean absorbent 10 and reduce the amount of water vapor supplied to the regeneration tower 8 without changing the water vapor supply conditions. That is, according to the present invention, the temperature of the rich absorbent 9 conveyed to the regeneration tower 8 can be adjusted in a wider range than the conventional method, so that the lean absorbent is reduced while reducing the amount of steam supplied to the regeneration tower 8. It is also possible to reduce 10 CO 2 loading.
　７　　吸収塔
　８　　再生塔
　９　　リッチ吸収液
　１０　リーン吸収液
　２１　リボイラ（第２熱交換器）
　３５　一次熱水
　３７　二次熱水
　３８　ＶＲ水蒸気
　３９　フラッシュ水蒸気（二次水蒸気）
　４１　ＶＲ吸収液蒸気（吸収液蒸気） 7 Absorption tower 8 Regeneration tower 9 Rich absorption liquid 10 Lean absorption liquid 21 Reboiler (second heat exchanger)
35 Primary hot water 37 Secondary hot water 38 VR water vapor 39 Flash water vapor (secondary water vapor)
41 VR absorption liquid vapor (absorption liquid vapor)

Claims (4)

  1. 　二酸化炭素を含む燃焼排ガスと、水及びアルカノールアミンを含む吸収液とを接触させて、前記二酸化炭素を前記吸収液に吸収させる吸収塔と、
    　前記二酸化炭素を吸収した吸収液を加熱して、前記吸収液から前記二酸化炭素を遊離させて回収して前記吸収液を再生する再生塔と、
    　前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を、前記二酸化炭素を遊離させて前記再生塔から前記吸収塔に搬送される吸収液で加熱する第１熱交換器を備えてなる二酸化炭素の回収装置において、
    　前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、大気圧よりも高圧の一次水蒸気により加熱して前記再生塔に戻す第２熱交換器と、
    　前記第２熱交換器で前記一次水蒸気が凝縮した一次熱水を抜き出して、前記一次水蒸気よりも低圧に調整された容器内に放出させて二次熱水と二次水蒸気を生成する第１フラッシュ容器と、
    　前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を前記二次熱水で加熱する第３熱交換器と、
    　前記二次水蒸気を加圧して前記第２熱交換器の前記一次水蒸気に合流させる第１圧縮機とを有してなることを特徴とする二酸化炭素の回収装置。     An absorption tower for contacting the combustion exhaust gas containing carbon dioxide with an absorption liquid containing water and alkanolamine to absorb the carbon dioxide in the absorption liquid;
    A regeneration tower that heats the absorption liquid that has absorbed the carbon dioxide, liberates and recovers the carbon dioxide from the absorption liquid, and regenerates the absorption liquid;
    A first heat exchanger that absorbs the carbon dioxide and heats the absorption liquid conveyed from the absorption tower to the regeneration tower with the absorption liquid that liberates the carbon dioxide and is conveyed from the regeneration tower to the absorption tower. In a carbon dioxide recovery device comprising:
    A second heat exchanger for extracting the absorption liquid from which the carbon dioxide has been liberated from the regeneration tower and heating it with primary steam at a pressure higher than atmospheric pressure and returning it to the regeneration tower;
    The first flash for generating the secondary hot water and the secondary steam by extracting the primary hot water condensed with the primary steam in the second heat exchanger and releasing it into a container adjusted to a pressure lower than that of the primary steam. A container,
    A third heat exchanger that absorbs the carbon dioxide and heats the absorption liquid conveyed from the absorption tower to the regeneration tower with the secondary hot water;
    A carbon dioxide recovery apparatus comprising: a first compressor that pressurizes the secondary steam to join the primary steam of the second heat exchanger.
  2. 　前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、前記再生塔よりも低圧に調整された容器内に放出させて前記再生塔から抜き出した吸収液よりも低温の吸収液蒸気と吸収液を生成する第２フラッシュ容器と、
    　前記低温の吸収液蒸気を加圧して前記再生塔に戻す第２圧縮機とを有し、
    　前記低温の吸収液は、前記第１熱交換器に供給されて、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を加熱することを特徴とする請求項１に記載の二酸化炭素の回収装置。     The absorption liquid liberated the carbon dioxide is extracted from the regeneration tower, discharged into a container adjusted to a lower pressure than the regeneration tower, and absorbed at lower temperature than the absorption liquid extracted from the regeneration tower. A second flash vessel for producing a liquid;
    A second compressor that pressurizes the low-temperature absorbent liquid vapor and returns it to the regeneration tower;
    The said low temperature absorption liquid is supplied to a said 1st heat exchanger, absorbs the said carbon dioxide, and heats the absorption liquid conveyed to the said regeneration tower from the said absorption tower, The Claim 1 characterized by the above-mentioned. The carbon dioxide recovery device described.
  3. 　二酸化炭素を含む燃焼排ガスと、水及びアルカノールアミンを含む吸収液とを接触させて、前記二酸化炭素を前記吸収液に吸収させる吸収塔と、
    　前記二酸化炭素を吸収した吸収液を加熱して、前記吸収液から前記二酸化炭素を遊離させて回収して前記吸収液を再生する再生塔と、
    　前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を、前記二酸化炭素を遊離させて前記再生塔から前記吸収塔に搬送される吸収液で加熱する熱交換器を備えてなる二酸化炭素の回収装置の運転方法であって、
    　前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、大気圧よりも高圧の一次水蒸気により加熱して前記再生塔に戻し、
    　前記一次水蒸気を凝縮して生成した一次熱水から前記一次熱水よりも低温の二次熱水と前記一次水蒸気よりも低圧の二次水蒸気を生成し、
    　前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を前記二次熱水で加熱し、
    　前記二次水蒸気を加圧して前記一次水蒸気に合流させることを特徴とする二酸化炭素の回収装置の運転方法。     An absorption tower for contacting the combustion exhaust gas containing carbon dioxide with an absorption liquid containing water and alkanolamine to absorb the carbon dioxide in the absorption liquid;
    A regeneration tower that heats the absorption liquid that has absorbed the carbon dioxide, liberates and recovers the carbon dioxide from the absorption liquid, and regenerates the absorption liquid;
    A heat exchanger that absorbs the carbon dioxide and transports the absorbent that is transported from the absorption tower to the regeneration tower with the absorbent that liberates the carbon dioxide and is transported from the regeneration tower to the absorption tower; A method of operating a carbon dioxide recovery device comprising:
    The absorption liquid liberated the carbon dioxide is extracted from the regeneration tower, heated by primary steam higher than atmospheric pressure and returned to the regeneration tower,
    Producing secondary hot water having a lower temperature than the primary hot water and secondary steam having a lower pressure than the primary steam from the primary hot water generated by condensing the primary steam,
    The absorption liquid that absorbs the carbon dioxide and is transported from the absorption tower to the regeneration tower is heated with the secondary hot water,
    A method for operating a carbon dioxide recovery apparatus, wherein the secondary water vapor is pressurized and merged with the primary water vapor.
  4. 　前記二酸化炭素を遊離させた吸収液を前記再生塔から抜き出して、前記再生塔から抜き出した吸収液よりも低温の吸収液蒸気と吸収液を生成し、
    　前記低温の吸収液蒸気を加圧して前記再生塔に戻し、
    　前記低温の吸収液を前記熱交換器に供給して、前記二酸化炭素を吸収して前記吸収塔から前記再生塔に搬送される吸収液を加熱することを特徴とする請求項３に記載の二酸化炭素の回収装置の運転方法。     The absorption liquid liberated the carbon dioxide is extracted from the regeneration tower to produce an absorption liquid vapor and an absorption liquid having a temperature lower than that of the absorption liquid extracted from the regeneration tower,
    Pressurizing the low-temperature absorption liquid vapor and returning it to the regeneration tower;
    The said low temperature absorption liquid is supplied to the said heat exchanger, the said carbon dioxide is absorbed, and the absorption liquid conveyed to the said regeneration tower from the said absorption tower is heated, The dioxide dioxide of Claim 3 characterized by the above-mentioned. Operation method of carbon recovery equipment.
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