JP2024023131A - Carbon dioxide recovery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon dioxide recovery device which can suppress energy cost.

SOLUTION: A carbon dioxide recovery device 1A makes an absorbing liquid absorb carbon dioxide included in carbon dioxide containing gas, and heats the absorbing liquid absorbing carbon dioxide to desorb and recover carbon dioxide. The carbon dioxide recovery device 1A includes a process tower 10 containing the absorbing liquid, and a heater 65A which heats, by heat exchange with exhaust gas, the absorbing liquid to 40-90°C which allows the absorbing liquid to desorb carbon dioxide.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

Application for application of Article 30, Paragraph 2 of the Patent Act Publisher name: National Urban Cleaning Council Public Interest Incorporated Association Publication name: Urban Cleaning, Volume 75, No. 365, Page 64 Publication date: January 2020 1st day of the month

The present invention relates to a carbon dioxide recovery device and a carbon dioxide recovery method, which make an absorption liquid absorb carbon dioxide contained in a carbon dioxide-containing gas, and heat the absorption liquid that has absorbed carbon dioxide to diffuse and recover carbon dioxide. Regarding.

As a method for recovering carbon dioxide, for example, a chemical absorption method that utilizes reaction absorption by a basic compound is known. In the chemical absorption method, carbon dioxide contained in the gas is brought into contact with an amine-based absorption liquid in an absorption tower, the absorption liquid that has absorbed carbon dioxide is sent from the absorption tower to a regeneration tower, and the regeneration tower extracts carbon dioxide from the absorption liquid. A carbon dioxide recovery device that diffuses and recovers carbon dioxide is known (for example, see Patent Document 1).

In the carbon dioxide recovery device described in Patent Document 1, a reboiler that uses steam as a heat source is provided at the bottom of the regeneration tower, and carbon dioxide is released from the absorption liquid by heating the absorption liquid by the reboiler. .

Japanese Patent Application Publication No. 11-267442

In the carbon dioxide recovery device described in Patent Document 1, carbon dioxide is dissipated by heating by a reboiler that uses steam as a heat source, so the thermal energy required to generate steam and the thermal energy required to raise the temperature of the absorption liquid are , thermal energy required to dissipate carbon dioxide from the absorption liquid, thermal energy to compensate for heat loss due to water evaporation of the absorption liquid, etc. Therefore, there is a problem in that a large amount of energy is required to dissipate the absorbed carbon dioxide, leading to an increase in energy costs.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a carbon dioxide recovery device and a carbon dioxide recovery method that can keep energy costs low.

The characteristic configuration of the carbon dioxide recovery device according to the present invention for solving the above problems is as follows:
A carbon dioxide recovery device that causes an absorption liquid to absorb carbon dioxide contained in a carbon dioxide-containing gas, and heats the absorption liquid that has absorbed the carbon dioxide to diffuse and recover the carbon dioxide,
a treatment tower containing the absorption liquid;
a heater that heats the absorption liquid to a temperature of 40 to 90°C at which the carbon dioxide can be dissipated by heat exchange with exhaust gas;
The goal is to prepare for

According to the carbon dioxide recovery device of this configuration, an absorption liquid capable of dissipating absorbed carbon dioxide at a temperature of 40 to 90° C. is used, and the absorption liquid is heated by a heater through heat exchange with exhaust gas. Here, the exhaust gas is normally discharged into the atmosphere and disposed of, and the temperature of the exhaust gas at the time of disposal is about 140 to 170°C. In this way, there is a sufficient temperature difference between the temperature at which the absorption liquid can dissipate carbon dioxide (40 to 90 degrees Celsius) and the exhaust gas temperature at the time of disposal (140 to 170 degrees Celsius). It can be heated to 40 to 90°C by a heater through heat exchange with exhaust gas, and carbon dioxide can be diffused and recovered from the absorption liquid in a treatment tower. Therefore, carbon dioxide can also be recovered from the waste heat of the exhaust gas, which is normally released into the atmosphere and discarded, and energy costs can be kept low by effectively utilizing the waste heat.

In the carbon dioxide recovery device according to the present invention,
The treatment tower includes an absorption tower that absorbs the carbon dioxide into the absorption liquid, and a regeneration tower that diffuses the carbon dioxide from the absorption liquid that has absorbed the carbon dioxide,
The absorption tower and the regeneration tower are connected so that the absorption liquid is circulated between the absorption tower and the regeneration tower, and the absorption liquid supplied from the absorption tower to the regeneration tower is heated. It is preferable that the heater is arranged so as to.

According to the carbon dioxide recovery device with this configuration, the absorption tower and the regeneration tower continuously absorb and dissipate carbon dioxide, and the absorption liquid supplied from the absorption tower to the regeneration tower uses the waste heat of the exhaust gas as a heat source. Since the carbon dioxide is heated by a heater, the carbon dioxide recovery efficiency can be improved while keeping the energy required for dissipating the absorbed carbon dioxide low.

In the carbon dioxide recovery device according to the present invention,
The treatment tower includes an absorption tower that absorbs the carbon dioxide into the absorption liquid, and a regeneration tower that diffuses the carbon dioxide from the absorption liquid that has absorbed the carbon dioxide,
The absorption tower and the regeneration tower are connected so that the absorption liquid is circulated between the absorption tower and the regeneration tower, and the absorption liquid is circulated between the regeneration tower and the heater. It is preferable that the regeneration tower and the heater are connected so that the regeneration tower and the heater are connected.

According to the carbon dioxide recovery device with this configuration, the absorption tower and the regeneration tower continuously absorb and dissipate carbon dioxide, and the absorption liquid circulated between the regeneration tower and the heater is used as waste gas. Since it is heated by a heater that uses heat as a heat source, it is possible to improve the carbon dioxide recovery efficiency while keeping the energy required to dissipate absorbed carbon dioxide low.

In the carbon dioxide recovery device according to the present invention,
It is preferable to include a pressure reducing means for reducing the pressure inside the regeneration tower.

According to the carbon dioxide recovery device having this configuration, the synergistic effect of the heating of the absorption liquid by the heater and the pressure reduction of the absorption liquid by the pressure reduction means makes it possible to further improve the carbon dioxide recovery efficiency and to reduce the amount of carbon dioxide. The absorption liquid can be regenerated to a state where it can be sufficiently absorbed.

In the carbon dioxide recovery device according to the present invention,
The heater includes a heat exchanger tube through which the exhaust gas is brought into contact with an outer surface and a heat medium is passed through the inside,
It is preferable that the outer surface temperature of the heat exchanger tube is set higher than the dew point of the exhaust gas.

According to the carbon dioxide recovery device with this configuration, the temperature of the outer surface of the heat transfer tube is set to be higher than the dew point of the exhaust gas, so corrosive components are not evaporated near the outer surface of the heat transfer tube due to contact with the exhaust gas. This creates a dominant atmosphere, and can prevent the generation of droplets containing corrosive components due to dew condensation. Therefore, there is an advantage that corrosion countermeasures (for example, anti-corrosion coating, fluororesin lining, etc.) for the casing of the heater or the like are unnecessary or can be simplified.

In the carbon dioxide recovery device according to the present invention,
The heater includes a heat exchanger tube through which the exhaust gas is brought into contact with an outer surface and a heat medium is passed through the inside,
The heat exchanger tube is made of a corrosion-resistant material,
It is preferable that the outer surface temperature of the heat exchanger tube is set to be equal to or lower than the dew point of the exhaust gas.

According to the carbon dioxide recovery device with this configuration, heat can be recovered to temperatures below the dew point using corrosion-resistant materials, so the amount of heat medium (steam, etc.) used in the carbon dioxide recovery device can be significantly reduced. can be reduced. Furthermore, by performing heat recovery to a temperature below the condensation temperature of water in the exhaust gas, thermal energy corresponding to the latent heat of water can also be recovered, making the effect even greater.

Next, the characteristic configuration of the carbon dioxide recovery method according to the present invention for solving the above problems is as follows:
an absorption step in which carbon dioxide contained in the carbon dioxide-containing gas is absorbed into an absorption liquid;
A recovery step of dissipating and recovering the carbon dioxide by heating the absorption liquid that has absorbed the carbon dioxide to a temperature of 40 to 90° C. at which the carbon dioxide can be dissipated through heat exchange with exhaust gas;
The goal is to include the following.

According to the carbon dioxide recovery method of this configuration, an absorption liquid capable of dissipating carbon dioxide absorbed in the absorption process at 40 to 90°C is used, and the absorption liquid is heated in the recovery process by heat exchange with exhaust gas. . Here, the exhaust gas is normally discharged into the atmosphere and disposed of, and the temperature of the exhaust gas at the time of disposal is about 140 to 170°C. In this way, there is a sufficient temperature difference between the temperature at which carbon dioxide can be dissipated from the absorption liquid (40 to 90 degrees Celsius) and the exhaust gas temperature at the time of disposal (140 to 170 degrees Celsius). The absorption liquid can be heated to 40 to 90°C by heat exchange with exhaust gas, and carbon dioxide can be diffused and recovered from the absorption liquid. Therefore, carbon dioxide can also be recovered from the waste heat of the exhaust gas, which is normally released into the atmosphere and discarded, and energy costs can be kept low by effectively utilizing the waste heat.

FIG. 1 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a second embodiment of the present invention. FIG. 3 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a third embodiment of the present invention. FIG. 4 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a fourth embodiment of the present invention. FIG. 5 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a fifth embodiment of the present invention. FIG. 6 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a sixth embodiment of the present invention. FIG. 7 is a block diagram showing a schematic configuration of a carbon dioxide recovery device according to a seventh embodiment of the present invention.

The present invention will be described below with reference to the drawings. Note that the following embodiments will be described using an example in which carbon dioxide is recovered from exhaust gas treated by exhaust gas treatment equipment in a biomass power generation facility. However, the present invention is not intended to be limited to the embodiments described below or the configurations described in the drawings. Note that the biomass fuel burned in the biomass power generation facility is a biological fuel extracted from organic resources in the natural world such as plants and agricultural products other than fossil fuels. Specifically, biomass fuels include waste wood, thinned wood, driftwood, grass, domestic waste, sludge, livestock manure, energy crops (agricultural crops), and recycled fuels made from these materials (pellets and chips). etc.

[First embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a carbon dioxide recovery apparatus 1A according to a first embodiment of the present invention. The carbon dioxide recovery device 1A shown in FIG. 1 causes an absorption liquid to absorb carbon dioxide contained in exhaust gas (carbon dioxide-containing gas) treated by an exhaust gas treatment equipment 200 in a biomass power generation facility, and then absorbs the absorption liquid that has absorbed carbon dioxide. It is configured to dissipate and recover carbon dioxide by heating.

<Exhaust gas treatment equipment>
The exhaust gas treatment equipment 200 is equipment that includes a bag filter, an induced draft fan, and the like. In the exhaust gas treatment facility 200, exhaust gas generated as a result of combustion of biomass fuel in a combustion furnace is introduced into a bag filter by an induced draft fan and subjected to dust removal treatment.

<Absorption liquid>
The absorption liquid is not particularly limited as long as it can diffuse absorbed carbon dioxide at 40 to 90°C, but for example, Japanese Patent Application Publication No. 2021-154236 and Japanese Patent Application Publication No. 2021-154237 The non-aqueous carbon dioxide absorption liquid disclosed in the above publication can be used.

<Carbon dioxide recovery device>
As shown in FIG. 1, the carbon dioxide recovery device 1A includes a treatment tower 10 that accommodates an absorption liquid.

<Processing tower>
The treatment tower 10 includes an absorption tower 3 that causes an absorption liquid to absorb carbon dioxide, and a regeneration tower 5 that diffuses carbon dioxide from the absorption liquid that has absorbed carbon dioxide.

<Absorption tower>
The absorption tower 3 may have any structure as long as it can absorb carbon dioxide into the absorption liquid, and is not particularly limited, and any known structure may be used. In the absorption tower 3, a gas inlet 11 is provided at the bottom, a gas outlet 13 is provided at the top, an absorbent outlet 15 is provided at the bottom, and an absorbent inlet 17 is provided at the top. ing.

<Regeneration Tower>
The regeneration tower 5 is not particularly limited as long as it has a structure that can diffuse carbon dioxide from the absorption liquid that has absorbed carbon dioxide, and a known structure can be used. In the regeneration tower 5, an absorption liquid inlet 21 is provided at the top, an absorption liquid outlet 23 is provided at the bottom, and a gas exhaust port 25 is provided at the top.

The gas inlet 11 of the absorption tower 3 and the exhaust gas treatment equipment 200 are connected by an exhaust gas supply pipe 31. A gas exhaust pipe 33 is connected to the gas exhaust port 13 of the absorption tower 3 . A gas exhaust pipe 35 is connected to the gas exhaust port 25 of the regeneration tower 5 .

The absorption liquid outlet 15 of the absorption tower 3 and the absorption liquid inlet 21 of the regeneration tower 5 are connected by an absorption liquid supply pipe 41. The absorption liquid inlet 17 of the absorption tower 3 and the absorption liquid outlet 23 of the regeneration tower 5 are connected by an absorption liquid reflux pipe 43. In this way, the absorption tower 3 and the regeneration tower 5 are connected by the absorption liquid supply pipe 41 and the absorption liquid reflux pipe 43 so that the absorption liquid is circulated between the absorption tower 3 and the regeneration tower 5.

A pretreatment facility 45 is provided in the middle of the exhaust gas supply pipe 31 . The pretreatment equipment 45 is configured to wet-process the exhaust gas by bringing the cleaning water added with chemicals into gas-liquid contact with the exhaust gas. In the pretreatment equipment 45, most of the harmful substances such as sulfur oxides, acidic gas components, dioxins, and heavy metals in the exhaust gas are separated and removed from the exhaust gas by washing water, and the exhaust gas is made suitable for absorbing carbon dioxide. The temperature is reduced to In addition, in the pretreatment equipment 45, the cleaning water whose pH has become slightly acidic after spraying may be neutralized and then sprayed again to remove the acidic gas by gas-liquid contact.

A pump 51 is installed in the absorption liquid supply pipe 41 . The absorption liquid contained in the absorption tower 3 is supplied to the regeneration tower 5 via the absorption liquid supply pipe 41 by operation of the pump 51. A pump 53 is installed in the absorption liquid reflux pipe 43 . The absorption liquid contained in the regeneration tower 5 is refluxed to the absorption tower 3 via the absorption liquid reflux pipe 43 by the operation of the pump 53.

<Decompression means>
A pump 55 that functions as a pressure reducing means of the present invention is interposed in the gas exhaust pipe 35. The pressure inside the regeneration tower 5 is reduced by the operation of the pump 55.

The carbon dioxide recovery device 1A further includes a temperature riser 60 that heats up the absorption liquid supplied from the absorption tower 3 to the regeneration tower 5, and a heater 65A that heats the absorption liquid heated by the temperature riser 60. ing.

<Heating device>
The temperature riser 60 includes a first heat exchanger 71 interposed in the absorption liquid supply pipe 41 and a second heat exchanger 72 interposed in the absorption liquid reflux pipe 43. In the temperature riser 60, a heat medium (for example, air or water) flows between the first heat exchanger 71 and the second heat exchanger 72, thereby increasing the absorption liquid flowing through the absorption liquid supply pipe 41. Heat exchange is performed between the absorbent liquid and the absorbent liquid flowing through the absorbent liquid return pipe 43, and the temperature of the absorbent liquid flowing through the absorbent liquid supply pipe 41 is increased.

<Heating device>
The heater 65A is connected to a third heat exchanger 73 that is installed downstream of the first heat exchanger 71 in the absorption liquid supply pipe 41, and on the exhaust gas flow upstream side of the pretreatment equipment 45 in the exhaust gas supply pipe 31. A fourth heat exchanger 74 is provided. In the heater 65A, a heat medium (for example, air, water, etc.) flows between the third heat exchanger 73 and the fourth heat exchanger 74, so that the absorption liquid flowing through the absorption liquid supply pipe 41 and , heat exchange is performed with the exhaust gas flowing through the exhaust gas supply pipe 31, and the absorption liquid flowing through the absorption liquid supply pipe 41 and heated by the temperature riser 60 (first heat exchanger 71) is heated. It is configured to

The fourth heat exchanger 74 is configured to include a heat exchanger tube whose outer surface is brought into contact with the exhaust gas and through which a heat medium flows inside. In the fourth heat exchanger 74, the outer surface of the heat exchanger tube that comes into contact with the exhaust gas in the heat exchanger tube, even under the condition that the exhaust gas amount is the smallest and/or the exhaust gas temperature is the lowest in the fluctuating range of the exhaust gas amount and exhaust gas temperature. The length, tube diameter, thickness, material, etc. of the heat transfer tube are set so that the temperature is higher than the dew point. Here, the dew point specifically refers to the temperature at which sulfuric acid gas turns into sulfuric acid and condenses.

In the fourth heat exchanger 74, the temperature of the outer surface of the heat exchanger tube is set to be higher than the dew point of the exhaust gas, so evaporation of corrosive components due to contact with the exhaust gas is dominant near the outer surface of the heat exchanger tube. This creates a safe atmosphere and prevents the generation of droplets containing corrosive components due to dew condensation. Therefore, there is an advantage that countermeasures against corrosion (for example, corrosion-resistant coating, fluororesin lining, etc.) for the casing of the fourth heat exchanger 74 are unnecessary or can be simplified.

Examples of the material for the heat exchanger tubes in the fourth heat exchanger 74 include corrosion-resistant metals such as stainless steel, Hastelloy, and Inconel, and nonmetallic materials such as fluororesin. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene/hexafluoropropylene copolymer (FEP), and tetrafluoroethylene/ethylene copolymer. Examples include polymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and the like.

The thickness of the fluororesin tube used as the heat exchanger tube is preferably 0.5 to 2.0 mm, more preferably 1.0 to 1.5 mm. If the thickness of the fluororesin tube is within the above numerical range, the high heat transfer performance of the heat transfer tube can be maintained.

When the heat medium is a gas, the outer diameter of the fluororesin tube is preferably φ10 to φ100 mm, more preferably φ18 to φ30 mm. Further, when the heat medium is a liquid, the diameter is preferably 4 to 15 mm, more preferably 8 to 13 mm. If the outer diameter is within the above numerical range, the heat exchanger tube will be less susceptible to pressure loss and will have good pressure resistance.

In the carbon dioxide recovery device 1A configured as described above, the absorption process in the absorption tower 3 and the recovery process in the regeneration tower 5 are performed continuously, and a temperature raising process is performed when implementing the recovery process. and a heating step.

<Absorption process>
The dust-removed exhaust gas sent out from the exhaust gas treatment equipment 200 is sent to the pretreatment equipment 45, where harmful substances are removed, and then sent into the absorption tower 3 via the exhaust gas supply pipe 31. . The exhaust gas sent into the absorption tower 3 comes into gas-liquid contact with the absorption liquid. As a result, carbon dioxide contained in the exhaust gas is absorbed into the absorption liquid. The treated liquid that has absorbed carbon dioxide is stored in the lower part of the absorption tower 3. On the other hand, the exhaust gas from which carbon dioxide has been removed is discharged to the outside of the absorption tower 3 via the gas discharge pipe 33. Note that "exhaust gas from which carbon dioxide has been removed" refers to both "exhaust gas from which all of the carbon dioxide contained in it has been removed" and "exhaust gas from which some of the contained carbon dioxide has been removed." This includes:

<Temperature raising process, heating process>
The absorption liquid stored in the lower part of the absorption tower 3 is supplied to the regeneration tower 5 via the absorption liquid supply pipe 41 by operation of the pump 51. At this time, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 is heated by a temperature riser 60 (first heat exchanger 71), and then heated to a temperature of 40 to 90 heated to ℃. In this way, by heating the treatment liquid before performing the regeneration step described below, it is possible to improve the carbon dioxide diffusion efficiency in the regeneration step.

<Regeneration process>
The inside of the regeneration tower 5 is depressurized by a pump 55 that functions as a decompression means (depressurization step). The absorption liquid heated by the heater 65A is supplied to the inside of the regeneration tower 5 under reduced pressure. In the regeneration tower 5, carbon dioxide is efficiently diffused from the absorption liquid due to the synergistic effect of the heating of the absorption liquid by the heater 65A and the pressure reduction of the absorption liquid by the pressure reduction means (pump 55). In this way, the carbon dioxide recovery efficiency can be further improved, and the absorption liquid can be regenerated to a state where carbon dioxide can be sufficiently absorbed.

In the regeneration process, the absorption liquid in the regeneration tower 5, which has been regenerated into a state in which carbon dioxide is diffused and can sufficiently absorb carbon dioxide, is refluxed to the absorption tower 3 via the absorption liquid reflux pipe 43 by the operation of the pump 53. be done. At this time, between the first heat exchanger 71 and the second heat exchanger 72, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 and the absorption liquid flowing from the regeneration tower 5 to the absorption tower 3 Heat exchange is performed between the absorbent and the absorbent flowing through the absorbent reflux pipe 43 toward the absorbent. As a result, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 becomes a source of cold heat, and the absorption liquid flowing through the absorption liquid reflux pipe 43 from the regeneration tower 5 toward the absorption tower 3 becomes the first. 2 is cooled by a heat exchanger 72.

According to the carbon dioxide recovery device 1A of the first embodiment, an absorption liquid capable of dissipating absorbed carbon dioxide at a temperature of 40 to 90°C is used, and the absorption liquid is heated by the heater 65A through heat exchange with the exhaust gas. Ru. Here, the exhaust gas is normally discharged into the atmosphere and disposed of, and the temperature of the exhaust gas at the time of disposal is about 140 to 170°C. In this way, there is a sufficient temperature difference between the temperature at which the absorption liquid can dissipate carbon dioxide (40 to 90 degrees Celsius) and the exhaust gas temperature at the time of disposal (140 to 170 degrees Celsius). It can be heated to 40 to 90° C. by the heater 65A through heat exchange with the exhaust gas, and carbon dioxide can be diffused and recovered from the absorption liquid in the regeneration tower 5. Therefore, carbon dioxide can also be recovered from the waste heat of the exhaust gas, which is normally released into the atmosphere and discarded, and energy costs can be kept low by effectively utilizing the waste heat.

Further, according to the carbon dioxide recovery device 1A, absorption and dissipation of carbon dioxide are continuously performed by the absorption tower 3 and the regeneration tower 5, and the absorption liquid supplied from the absorption tower 3 to the regeneration tower 5 is Since it is heated by the heater 65A using waste heat as a heat source, it is possible to improve the recovery efficiency of carbon dioxide while keeping the energy required for dissipating the absorbed carbon dioxide low.

[Second embodiment]
FIG. 2 is a block diagram showing a schematic configuration of a carbon dioxide recovery device 1B according to a second embodiment of the present invention. In the second embodiment, parts that are the same as or similar to those in the first embodiment are given the same reference numerals in the figures, and detailed explanations thereof are omitted.The following description focuses on parts unique to the second embodiment. Let me explain.

In the carbon dioxide recovery apparatus 1B of the second embodiment, the heater 65B includes a reboiler 80 attached to the regeneration tower 5. An absorption liquid drain pipe 81 and an absorption liquid return pipe 83 are connected to the reboiler 80 . The absorption liquid drain pipe 81 is arranged so as to be connected to the reboiler 80 in a form that branches from the absorption liquid reflux pipe 43 . The absorption liquid return pipe 83 is arranged to connect the reboiler 80 and the lower part of the regeneration tower 5. Further, the reboiler 80 is connected so that the exhaust gas that has been subjected to dust removal treatment and sent out from the exhaust gas treatment equipment 200 is introduced and led out. In the heater 65B, heat exchange is performed between the absorption liquid introduced into the reboiler 80 via the absorption liquid extraction pipe 81 and the exhaust gas introduced into the reboiler 80 via the exhaust gas supply pipe 31, and the exhaust gas is removed. The absorption liquid that has absorbed heat is returned to the inside of the regeneration tower 5 via the absorption liquid return pipe 83, thereby heating the absorption liquid in the regeneration tower 5.

In the carbon dioxide recovery device 1B configured as described above, the absorption process in the absorption tower 3 and the recovery process in the regeneration tower 5 are performed continuously, and a temperature raising process is performed when implementing the recovery process. and a heating step.

<Absorption process>
The dust-removed exhaust gas sent out from the exhaust gas treatment equipment 200 is sent to the pretreatment equipment 45 via the reboiler 80, and after harmful substances are removed in the pretreatment equipment 45, it is sent to the absorption tower via the exhaust gas supply pipe 31. It is sent inside 3. The exhaust gas sent into the absorption tower 3 comes into gas-liquid contact with the absorption liquid. As a result, carbon dioxide contained in the exhaust gas is absorbed into the absorption liquid. The treated liquid that has absorbed carbon dioxide is stored in the lower part of the absorption tower 3. On the other hand, the exhaust gas from which carbon dioxide has been removed is discharged to the outside of the absorption tower 3 via the gas discharge pipe 33.

<Temperature raising process, heating process>
The absorption liquid stored in the lower part of the absorption tower 3 is supplied to the regeneration tower 5 via the absorption liquid supply pipe 41 by operation of the pump 51. At this time, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 is heated by the temperature riser 60 (first heat exchanger 71), and then sent into the regeneration tower 5. It will be done. The absorption liquid inside the regeneration tower 5 is heated to 40 to 90° C. by the heater 65B. In this way, by heating the treatment liquid before performing the regeneration step described below, it is possible to improve the carbon dioxide diffusion efficiency in the regeneration step.

<Regeneration process>
The inside of the regeneration tower 5 is depressurized by a pump 55 that functions as a decompression means (depressurization step). In the regeneration tower 5, carbon dioxide is efficiently diffused from the absorption liquid due to the synergistic effect of the heating of the absorption liquid by the heater 65B and the pressure reduction of the absorption liquid by the pressure reduction means (pump 55). In this way, the carbon dioxide recovery efficiency can be further improved, and the absorption liquid can be regenerated to a state where carbon dioxide can be sufficiently absorbed.

In the regeneration process, the absorption liquid inside the regeneration tower 5, which has been regenerated into a state in which carbon dioxide is diffused and can sufficiently absorb carbon dioxide, is returned to the absorption tower 3 through the absorption liquid reflux pipe 43 by the operation of the pump 53. It is recycled. At this time, between the first heat exchanger 71 and the second heat exchanger 72, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 and the absorption liquid flowing from the regeneration tower 5 to the absorption tower 3 Heat exchange is performed between the absorbent and the absorbent flowing through the absorbent reflux pipe 43 toward the absorbent. As a result, the absorption liquid flowing through the absorption liquid supply pipe 41 from the absorption tower 3 toward the regeneration tower 5 becomes a source of cold heat, and the absorption liquid flowing through the absorption liquid reflux pipe 43 from the regeneration tower 5 toward the absorption tower 3 becomes the first. 2 is cooled by a heat exchanger 72.

Similarly to the carbon dioxide recovery device 1A of the first embodiment, the carbon dioxide recovery device 1B of the second embodiment uses an absorption liquid that can dissipate absorbed carbon dioxide at a temperature of 40 to 90°C. Due to the exchange, the absorption liquid is heated to 40 to 90° C. by the heater 65B. Therefore, in the second embodiment as well, energy costs can be kept low by effectively utilizing waste heat, similarly to the first embodiment.

[Third embodiment]
FIG. 3 is a block diagram showing a schematic configuration of a carbon dioxide recovery device 1C according to a third embodiment of the present invention. In the third embodiment, parts that are the same as or similar to those in the second embodiment are given the same reference numerals in the figures, and detailed explanations thereof are omitted.The following description focuses on parts unique to the third embodiment. Let me explain.

In the carbon dioxide recovery apparatus 1C of the third embodiment, the heater 65C includes a heat transfer jacket 85 attached to the lower part of the regeneration tower 5. The exhaust gas supply pipe 31 is connected to the heat transfer jacket 85 so that the exhaust gas that has been subjected to dust removal treatment and sent out from the exhaust gas treatment equipment 200 is introduced and led out. In the heater 65C, while the exhaust gas passes through the heat transfer jacket 85 and exits, heat is generated between the absorption liquid inside the regeneration tower 5 and the exhaust gas introduced into the heat transfer jacket 85 of the regeneration tower 5. The exchange is performed to heat the absorption liquid inside the regeneration tower 5.

In the carbon dioxide recovery device 1C of the third embodiment, the only difference is the structure of the heater 65C from the heater 65B in the carbon dioxide recovery device 1B of the second embodiment, and other than that, the structure is basically the same as that of the carbon dioxide recovery device 1B. It has a similar configuration. Therefore, the third embodiment can also provide the same effects as the second embodiment.

[Fourth embodiment]
FIG. 4 is a block diagram showing a schematic configuration of a carbon dioxide recovery device 1D according to a fourth embodiment of the present invention. In the fourth embodiment, the same or similar parts as in each of the above embodiments are denoted by the same reference numerals in the drawings, and descriptions of parts that overlap with those in each of the above embodiments will be omitted.

As shown in FIG. 4, the carbon dioxide recovery apparatus 1D of the fourth embodiment includes a single-column treatment tower 100 that accommodates an absorption liquid. In the treatment tower 100, the absorption liquid and the exhaust gas are brought into contact inside the treatment tower 100, and carbon dioxide is recovered by utilizing the absorption/dissipation of carbon dioxide with respect to the absorption liquid inside the treatment tower 100. is configured to take place.

<Processing tower>
The treatment tower 100 may have any structure as long as it can perform batch processing of absorption/dissipation of carbon dioxide in the absorption liquid in a single tower without circulating the absorption liquid, and is not particularly limited, and may have a known structure. can be used. In the processing tower 100, a gas inlet 101 is provided at the bottom, and a gas outlet 103 is provided at the top. An absorbent liquid outlet 105 is provided at the bottom, and an absorbent liquid inlet 107 is provided at a position opposite to the gas inlet 101 at the bottom.

The gas inlet 101 of the treatment tower 100 and the exhaust gas treatment equipment 200 are connected by an exhaust gas supply pipe 31. A gas exhaust pipe 35 is connected to the gas exhaust port 103 of the processing tower 100 .

In the carbon dioxide recovery apparatus 1D of the fourth embodiment, the heater 65D includes a reboiler 80 attached to the regeneration tower 5. An absorption liquid drain pipe 81 and an absorption liquid return pipe 83 are connected to the reboiler 80 . The absorption liquid drain pipe 81 is arranged to connect the absorption liquid discharge port 105 and the reboiler 80. The absorption liquid return pipe 83 is arranged to connect the reboiler 80 and the absorption liquid introduction port 107. Further, the reboiler 80 is connected so that the exhaust gas that has been subjected to dust removal treatment and sent out from the exhaust gas treatment equipment 200 is introduced and led out via the exhaust gas flow path switching means 110. In the heater 65D, heat exchange is performed between the absorption liquid introduced into the reboiler 80 via the absorption liquid extraction pipe 81 and the exhaust gas introduced into the reboiler 80 via the exhaust gas supply pipe 31, and the exhaust gas is The absorption liquid that has absorbed heat is returned to the inside of the processing tower 100 via the absorption liquid return pipe 83, thereby heating the absorption liquid inside the processing tower 100.

Although detailed explanation with illustrations will be omitted, the exhaust gas flow path switching means 110 shown in FIG. It is configured to switch between a state in which the exhaust gas is supplied to the processing tower 100 and a state in which it is introduced into and led out from the reboiler 80.

In the carbon dioxide recovery apparatus 1D configured as described above, the absorption process and the recovery process are performed alternately in the single-column treatment tower 100.

<Absorption process>
The absorption process is performed in a state where the exhaust gas flow path switching means 110 is switched to supply the exhaust gas sent out from the exhaust gas treatment equipment 200 to the treatment tower 100. The dust-removed exhaust gas sent out from the exhaust gas treatment equipment 200 is pretreated in the pretreatment equipment 45 and then sent into the absorption tower 3 via the exhaust gas supply pipe 31 . The exhaust gas sent into the absorption tower 3 comes into gas-liquid contact with the absorption liquid. As a result, carbon dioxide contained in the exhaust gas is absorbed into the absorption liquid. On the other hand, the exhaust gas from which carbon dioxide has been removed is discharged to the outside of the treatment tower 100 via the gas discharge pipe 35 by the operation of the pump 55.

<Regeneration process (depressurization process, heating process)>
The absorption process is performed in a state where the exhaust gas flow path switching means 110 is switched to introduce and lead out the exhaust gas sent out from the exhaust gas treatment equipment 200 into and out of the reboiler 80 . The inside of the treatment tower 100 is depressurized by a pump 55 that functions as a decompression means (depressurization step). The absorption liquid inside the treatment tower 100 is heated to 40 to 90° C. by the heater 65D. In this manner, in the treatment tower 100, carbon dioxide is efficiently diffused from the absorption liquid due to the synergistic effect of the heating of the absorption liquid by the heater 65D and the pressure reduction of the absorption liquid by the pressure reduction means (pump 55). In this way, the carbon dioxide recovery efficiency can be further improved, and the absorption liquid can be regenerated to a state where carbon dioxide can be sufficiently absorbed.

According to the carbon dioxide recovery device 1D of the fourth embodiment, carbon dioxide can be recovered with a simpler configuration than the carbon dioxide recovery devices 1A to 1C described above through batch processing using the single-column type processing tower 100. .

[Fifth embodiment]
FIG. 5 is a block diagram showing a schematic configuration of a carbon dioxide recovery device 1E according to a fifth embodiment of the present invention. In the fifth embodiment, parts that are the same as or similar to those in the fourth embodiment are given the same reference numerals in the figures, and detailed explanations thereof are omitted.The following description focuses on parts unique to the fifth embodiment. Let me explain.

In the carbon dioxide recovery device 1E of the fifth embodiment, the heater 65E includes a heat transfer jacket 85 attached to the lower part of the treatment tower 100. The exhaust gas flow path switching means 110 is configured to switch between a state in which the exhaust gas after dust removal sent out from the exhaust gas treatment equipment 200 is supplied to the treatment tower 100 and a state in which it is introduced into and led out from the heat transfer jacket 85. There is.

In the carbon dioxide recovery device 1E of the fifth embodiment, the structure of the heater 65E is only different from the heater 65D in the carbon dioxide recovery device 1D of the fourth embodiment, and other than that, the structure is basically the same as that of the carbon dioxide recovery device 1D. It has a similar configuration. Therefore, the fifth embodiment can also provide the same effects as the fourth embodiment.

[Sixth embodiment]
FIG. 6 is a block diagram showing a schematic configuration of a carbon dioxide recovery apparatus 1F according to a sixth embodiment of the present invention. In the sixth embodiment, parts that are the same as or similar to those in the first embodiment are given the same reference numerals in the figures, and detailed explanations thereof are omitted.The following description focuses on parts unique to the sixth embodiment. Let me explain.

As shown in FIG. 1, in the carbon dioxide recovery apparatus 1A of the first embodiment, the temperature riser 60 includes two heat exchangers, a first heat exchanger 71 and a second heat exchanger 72. A heat medium (for example, air or water) flows between the heat exchanger 71 and the second heat exchanger 72, so that the absorption liquid flows through the absorption liquid supply pipe 41 and the absorption liquid return pipe 43. It is configured such that heat exchange is performed with the absorption liquid, and the temperature of the absorption liquid flowing through the absorption liquid supply pipe 41 is increased. On the other hand, as shown in FIG. 6, in the carbon dioxide recovery apparatus 1F of the sixth embodiment, the temperature riser 60 allows heat exchange between the absorption liquid supply pipe 41 and the absorption liquid return pipe 43. A single heat exchanger 70 is provided between the liquid supply pipe 41 and the absorption liquid return pipe 43. In this heat exchanger 70, heat exchange is directly performed between the absorption liquid flowing through the absorption liquid supply pipe 41 and the absorption liquid flowing through the absorption liquid return pipe 43. is configured such that the temperature is increased. The carbon dioxide recovery device 1F of the sixth embodiment can also provide the same effects as the carbon dioxide recovery device 1A of the first embodiment.

[Seventh embodiment]
FIG. 7 is a block diagram showing a schematic configuration of a carbon dioxide recovery device 1G according to the seventh embodiment of the present invention. In the seventh embodiment, parts that are the same as or similar to those in the sixth embodiment are given the same reference numerals in the figures, and detailed explanations thereof are omitted.The following description focuses on parts unique to the seventh embodiment. Let me explain.

As shown in FIG. 6, in the carbon dioxide recovery apparatus 1F of the sixth embodiment, the heater 65A includes two heat exchangers, a third heat exchanger 73 and a fourth heat exchanger 74. By flowing a heat medium (for example, air or water) between the exchanger 73 and the fourth heat exchanger 74, the absorption liquid flowing through the absorption liquid supply pipe 41 and the exhaust gas flowing through the exhaust gas supply pipe 31 are separated. Heat exchange is performed between them, and the absorption liquid flowing through the absorption liquid supply pipe 41 and heated by the temperature riser 60 (heat exchanger 70) is heated. On the other hand, as shown in FIG. 7, in the carbon dioxide recovery apparatus 1G of the seventh embodiment, the heater 65A supplies the absorption liquid to the absorption liquid supply pipe 41 and the exhaust gas supply pipe 31 so that heat can be exchanged between the absorption liquid supply pipe 41 and the exhaust gas supply pipe 31. A single heat exchanger 75 is provided between the pipe 41 and the exhaust gas supply pipe 31. In this heat exchanger 75, heat exchange is directly performed between the absorption liquid flowing through the absorption liquid supply pipe 41 and the exhaust gas flowing through the exhaust gas supply pipe 31. 60 (heat exchanger 70), the absorption liquid is heated after being heated. The carbon dioxide recovery device 1G of the seventh embodiment can also provide the same effects as the carbon dioxide recovery device 1F of the sixth embodiment.

As above, the carbon dioxide recovery device and carbon dioxide recovery method of the present invention have been described based on a plurality of embodiments, but the present invention is not limited to the configuration described in the above embodiments. The configuration may be modified as appropriate without departing from the spirit of the invention, such as by appropriately combining the described configurations.

In each of the embodiments described above, there is also a mode in which the pump 55 functioning as the pressure reducing means of the present invention is omitted.

In the first embodiment, an example was shown in which the outer surface temperature of the heat transfer tube in the fourth heat exchanger 74 is set to be higher than the dew point of the exhaust gas. There is also a mode in which heat exchange is performed until the temperature reaches the temperature below. In this case, it is preferable to use a heat exchanger tube made of a corrosion-resistant material. By recovering heat to a temperature below the dew point using a corrosion-resistant material, the amount of heat medium (steam, etc.) used in the carbon dioxide recovery device 1A can be significantly reduced. Furthermore, by performing heat recovery to a temperature below the condensation temperature of water in the exhaust gas, thermal energy corresponding to the latent heat of water can also be recovered, making the effect even greater. Furthermore, if sufficient heat is not recovered from the exhaust gas introduced from the exhaust gas treatment equipment 200 to the pretreatment equipment 45, a large amount of cooling water is required to cool the exhaust gas by wet treatment in the pretreatment equipment 45. By performing heat recovery to a temperature below the dew point, it is possible to reduce the load on the wet treatment performed in the pretreatment equipment 45.

The carbon dioxide capture device and the carbon dioxide capture method of the present invention can be used, for example, in thermal power generation facilities, steel plants, oil refineries, etc., to collect carbon dioxide contained in exhaust gas generated by combustion of fossil fuels, and in hydrogen production facilities, to remove off-gas Carbon dioxide contained in the exhaust gas generated from the combustion of waste at general waste incineration facilities; Carbon dioxide contained in the exhaust gas generated from the combustion of biomass fuel at biomass power generation facilities. It can be used for separating and recovering carbon, etc.

1A to 1G Carbon dioxide recovery device 3 Absorption tower 5 Regeneration tower 10 Treatment tower 55 Pressure reduction means 65A to 65E Heater 100 Treatment tower

Claims (4)

A carbon dioxide recovery device that causes an absorption liquid to absorb carbon dioxide contained in a carbon dioxide-containing gas, and heats the absorption liquid that has absorbed the carbon dioxide to diffuse and recover the carbon dioxide,
an absorption tower that accommodates the absorption liquid and causes the carbon dioxide to be absorbed into the absorption liquid;
a regeneration tower that accommodates the absorption liquid and diffuses the carbon dioxide from the absorption liquid that has absorbed the carbon dioxide;
an absorption liquid supply pipe and an absorption liquid reflux pipe that connect the absorption tower and the regeneration tower so that the absorption liquid is circulated between the absorption tower and the regeneration tower;
The absorption liquid flowing through the absorption liquid supply pipe from the absorption tower toward the regeneration tower is heated by heat exchange with the absorption liquid flowing through the absorption liquid reflux pipe from the regeneration tower toward the absorption tower. A heating device,
Heating the absorption liquid that flows through the absorption liquid supply pipe and has been heated by the temperature riser to a temperature of 40 to 90°C at which the carbon dioxide can be dissipated by heat exchange with the dust-removed exhaust gas. The vessel and
A carbon dioxide recovery device equipped with After the dust removal treatment, the exhaust gas cleaned by wet treatment is sent to the absorption tower as the carbon dioxide-containing gas,
The carbon dioxide recovery apparatus according to claim 1, wherein the heater exchanges heat with the exhaust gas before being wet-treated. The heater includes a heat exchanger tube made of a corrosion-resistant material, the outer surface of which is brought into contact with the exhaust gas, and a heat medium is passed through the interior of the heater, and the outer surface temperature of the heat exchanger tube is lower than or equal to the dew point of the exhaust gas. The carbon dioxide recovery device according to claim 2, wherein the heat exchange is performed until the carbon dioxide recovery device becomes . The carbon dioxide recovery device according to claim 3, wherein the heater further performs heat exchange to a temperature below the condensation temperature of moisture in the exhaust gas.

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