JP5518164B2 - CO2 recovery apparatus and method - Google Patents

Description

The present invention relates to a CO ₂ recovery apparatus and method for energy saving.

In recent years, the greenhouse effect due to CO ₂ has been pointed out as one of the causes of global warming, and countermeasures have become urgent internationally to protect the global environment. The source of CO ₂ extends to all human activity fields that burn fossil fuels, and there is a tendency for the demand for emission control to become stronger. Along with this, for a power generation facility such as a thermal power plant that uses a large amount of fossil fuel, a method for removing the CO ₂ in the combustion exhaust gas by bringing the combustion exhaust gas of the boiler into contact with the amine-based CO ₂ absorbent and recovering it, and A method of storing the recovered CO ₂ without releasing it to the atmosphere has been energetically studied.

Further, as a step of removing and recovering CO ₂ from the combustion exhaust gas using the above-mentioned CO ₂ absorption liquid, a step of bringing the combustion exhaust gas and the CO ₂ absorption liquid into contact with each other in an absorption tower, an absorption liquid that has absorbed CO ₂ is used. Heating is performed in a regeneration tower to liberate CO ₂ and regenerate the absorption liquid, which is then recycled to the absorption tower and reused (Patent Document 1).

Japanese Patent Laid-Open No. 7-51537

In the method of absorbing and removing and recovering CO ₂ from a CO ₂ -containing gas such as combustion exhaust gas using the CO ₂ absorbing liquid and the process, since these processes are added to the combustion equipment, the operating cost is increased. Must be reduced as much as possible. In particular, among the above steps, the regeneration step consumes a large amount of heat energy, so it is necessary to make it an energy saving process as much as possible.

In view of the above problems, an object of the present invention is to provide a CO ₂ recovery device and method that further improve energy efficiency.

The first aspect of the present invention to solve the above problems, an absorption tower for removing CO ₂ by contacting the gas with CO ₂ absorbing liquid containing CO _2, the rich solution that has absorbed CO ₂ A regeneration tower for regenerating, and a CO ₂ recovery device for reusing a lean solution from which CO ₂ has been removed in the regeneration tower in an absorption tower, wherein the regeneration tower has a plurality of stages, and CO ₂ is introduced from the lower part of the upper regeneration tower. A semi-lean solution from which a part of the semi-lean solution has been removed and introduced into the upper part of the lower regeneration tower, a lean solution heat exchanger interposed in the extraction tube and heating the semi-lean solution by residual heat of the lean solution; And a CO ₂ recovery device.

According to a second invention, in the first invention, the first lean solution heat exchanger that is interposed in the extraction pipe and that is heated by the residual heat of the lean solution, and the residual heat of the lean solution after the semi-lean solution is heated there a second lean-solution heat exchanger for heating the rich solution, the CO ₂ recovery apparatus characterized by comprising comprises a.

A third aspect of the present invention is the CO _{2 according to} the first or second aspect, further comprising a steam condensate heat exchanger that is interposed in the extraction pipe and exchanges heat of the semi-lean solution with steam condensate. In the recovery unit.

According to a fourth invention, in the first or second invention, the regeneration tower is divided into an upper regeneration tower, a middle regeneration tower and a lower regeneration tower which are divided into upper, middle and lower parts, and CO ₂ is supplied from the lower part of the upper regeneration tower. A semi-lean solution partially removed and introduced into the upper part of the middle regeneration tower; a first lean solution heat exchanger interposed in the extraction tube and heated by the residual heat of the lean solution; A semi-lean solution from which a part of CO ₂ has been removed is withdrawn from the lower part of the regeneration tower, and is inserted into the second withdrawal pipe to be introduced into the upper part of the lower regeneration tower, and the second withdrawal pipe, and the semi-lean solution is steam condensed water. A steam condensate heat exchanger for exchanging heat with the gas, and a semi-lean solution supply pipe branched from the second extraction pipe and supplying the semi-lean solution to the middle stage of the absorption tower. _{2 in the} recovery device.

A fifth invention is a gas and the CO ₂ absorbing liquid containing CO ₂ is contacted in absorption column after removal of the CO _2, reproduces the rich solution that has absorbed the CO ₂ in the regeneration tower, then regeneration A CO ₂ recovery method in which a lean solution from which CO ₂ has been removed is reused in an absorption tower, wherein the regeneration tower has a plurality of stages, and a semi-lean solution from which a portion of CO ₂ has been partially removed from the lower part of the regeneration tower on the upper stage side. A CO ₂ recovery method is characterized in that the semi-lean solution extracted by the extraction pipe is heated by the residual heat of the lean solution while being extracted by the extraction pipe and introduced into the upper part of the lower regeneration tower.

According to a sixth aspect, in the fifth aspect, the semi-lean solution extracted by the extraction pipe is heated by the first lean solution heat exchanger by the residual heat of the lean solution, and the lean after the semi-lean solution is heated In the CO ₂ recovery method, the rich solution 14 is heated by the second lean solution heat exchanger with the residual heat of the solution.

According to the present invention, by using the residual heat of the steam condensate, it is possible to provide a CO ₂ recovery apparatus and method which aimed at energy saving.
In addition, when regenerating a rich solution that has absorbed CO ₂ in a regeneration tower, a semi-lean solution from which CO ₂ extracted from the middle of the regeneration tower is partially removed and heated by residual heat of the lean solution, energy efficiency It is possible to provide a CO ₂ recovery apparatus and method with improved performance.

FIG. 1 is a schematic view of a CO ₂ recovery apparatus according to the first embodiment. FIG. 2 is a schematic diagram of a CO ₂ recovery apparatus according to the _second embodiment. FIG. 3 is a schematic view of a CO ₂ recovery device according to the third embodiment. FIG. 4 is a schematic view of a CO ₂ recovery device according to the fourth embodiment. FIG. 5 is a schematic view of a CO ₂ recovery device according to the fifth embodiment. FIG. 6 is a schematic view of a CO ₂ recovery device according to the sixth embodiment. FIG. 7 is a schematic view of a CO ₂ recovery device according to the seventh embodiment. FIG. 8 is a schematic view of a CO ₂ recovery device according to the eighth embodiment. FIG. 9 is a schematic view of a CO ₂ recovery device according to the ninth embodiment. FIG. 10 is a schematic diagram of the CO ₂ recovery apparatus according to the first embodiment. FIG. 11 is a schematic view of a CO ₂ recovery device according to the second embodiment. FIG. 12 is a schematic diagram of a CO ₂ recovery device according to the third embodiment. FIG. 13 is a schematic view of a CO ₂ recovery device according to the fourth embodiment. FIG. 14 is a schematic view of a CO ₂ recovery device according to the fifth embodiment. FIG. 15 is a schematic view of a CO ₂ recovery device according to the sixth embodiment. FIG. 16 is a schematic view of a CO ₂ recovery device according to the seventh embodiment. FIG. 17 is a schematic view of a CO ₂ recovery device according to the eighth embodiment. FIG. 18 is a schematic view of a CO ₂ recovery device according to the ninth embodiment. FIG. 19 is a schematic view of a CO ₂ recovery device according to the tenth embodiment. FIG. 20 is a schematic view of a CO ₂ recovery device according to the eleventh embodiment. FIG. 21 is a schematic view of a CO ₂ recovery device according to the twelfth embodiment. FIG. 22 is a schematic diagram of a CO ₂ recovery apparatus according to a conventional example.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.
Hereinafter, embodiments of the present invention will be described, and then preferred examples will be described in detail.

[First Embodiment]
FIG. 1 is a schematic diagram of a CO ₂ recovery apparatus according to the first embodiment.
As shown in FIG. 1, CO ₂ recovery apparatus according to a first embodiment of the present invention, by contacting the CO ₂ absorbing liquid 12 that absorbs CO ₂ containing gas 11 and CO ₂ containing CO ₂ an absorption tower 13 for removing CO _2, the regenerator 15 to regenerate the rich solution 14 that has absorbed CO _2, recycled in the absorption column 13 the lean solution (regenerated solution) 16 was removed CO ₂ in the regeneration tower 15 a CO ₂ recovery apparatus, the regeneration heater 18 to heat exchange with high-temperature steam 17 extracted lean solution 16 collected in the bottom portion near the regenerator 15 to the outside, the rich to the regenerator 15 from the absorption tower 13 A rich solution supply pipe 20 that supplies the solution 14 is provided with a steam condensed water heat exchanger 21 that heats the rich solution 14 by the residual heat of the steam condensed water 19 from the regeneration heater 18. is there.

In this embodiment, the lean solution 16 is supplied from the regeneration tower 15 to the absorption tower 13 through the lean solution supply pipe 22. The rich solution supply pipe 20 is provided with a lean solution heat exchanger 23 for heating the rich solution 14 by the residual heat of the lean solution 16.
In FIG. 1, reference numeral 8 is a nozzle, 9 is a chimney tray, 10 is a CO ₂ removal exhaust gas, 25 a and 25 _b are packed beds arranged in the absorption tower 13, and 26 a and 26 _b are arranged inside the regeneration tower 15. Each of the provided packed layers is illustrated.

  The kind of heat exchanger used in the present embodiment is not particularly limited, and for example, a known heat exchanger such as a plate heat exchanger or a swell & tube heat exchanger may be used.

Although there is no particular limitation is imposed on the CO ₂ absorbing solution which can be used in the present invention, it can be exemplified hindered amine having alkanolamine and alcoholic hydroxyl group. Examples of such alkanolamines include monoethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine, but monoethanolamine (MEA) is usually preferred. Examples of the hindered amine having an alcoholic hydroxyl group include 2-amino-2-methyl-1-propanol (AMP), 2- (ethylamino) -ethanol (EAE), 2- (methylamino) -ethanol (MAE), 2- (Diethylamino) -ethanol (DEAE) etc. can be illustrated.

  In this embodiment, since the steam condensed water heat exchanger 21 for heating the rich solution 14 by the residual heat of the steam condensed water 19 from the regeneration heater 18 is provided, the steam condensation used in the regeneration heater 18 is provided. By effectively using the residual heat of the water 19, the supply temperature of the rich solution 14 supplied to the regeneration tower 15 can be raised, and as a result, the amount of steam supplied in the regeneration tower 15 can be reduced.

Here, CO ₂ containing gas 11 supplied to the CO ₂ removing device is cooled by a not-shown cooling device, it is supplied at about 40 to 50 ° C.. On the other hand, the lean solution 16 as the regenerated absorbent 12 is cooled to about 40 ° C. by a cooling device (not shown).
The rich solution from the absorption tower 13 of the CO ₂ removal device is sent to the regeneration tower 15 at about 50 ° C. by a heating reaction. The regeneration tower 15 is fed at about 110 ° C. by the lean solution heat exchanger 23, but the steam condensate heat exchanger 21 is installed by the heat of the steam condensate (for example, at 137 ° C.). Thus, the temperature of the rich solution 14 can be increased by several degrees.

In the configuration of FIG. 1, a flash drum for flushing the rich solution is provided either before or after the steam condensate heat exchanger 21, and the CO ₂ contained in the rich solution is removed from the regeneration tower by the flash drum. Can be dissipated. As a result, a part of CO ₂ in the rich solution 14 regenerated in the regeneration tower 15 is removed in advance by the flash drum, so that the steam supply amount used for CO ₂ removal in the regeneration tower 15 can be reduced.

[Second Embodiment]
FIG. 2 is a schematic view of a CO ₂ recovery apparatus according to the _second embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus in the first embodiment, description thereof will be omitted given the same reference numerals.
As shown in FIG. 2, the CO ₂ recovery device according to the second embodiment of the present invention has a branch portion provided in a rich solution supply pipe 20 that further branches the rich solution 14 in the configuration of the first embodiment. 24, a steam condensate heat exchanger 21 that heats the rich solution 14 and is provided in the first rich solution supply pipe 20-1 branched at the branch portion 24, and the steam condensate heat exchanger 21 The flash drum 27 provided on the downstream side and the branched second rich solution supply pipe 20-2 are provided, and the rich solution 14 is removed by the residual heat of the semi-lean solution 28 from which the CO ₂ is partially removed by the flash drum 27. A semi-lean solution heat exchanger 29 for heating is provided, and an end portion of a semi-lean solution supply pipe 30 for supplying the semi-lean solution 28 is connected to the middle portion of the absorption tower 13. Further, the second rich solution supply pipe 20-2 is connected to the vicinity of the upper stage of the regeneration tower 15, and CO ₂ is removed and recovered in the regeneration tower 15.

In the present embodiment, the steam condensed water heat exchanger 21 that heats the rich solution 14 by the residual heat of the steam condensed water 19 from the regeneration heater 18 is provided, and the rich solution is heated by the residual heat of the steam condensed water. The remaining heat of the steam condensate 19 used in the regenerative heater 18 is effectively used. Further, the rich solution 14 that has obtained the residual heat is then introduced into the flash drum 27. Further, the CO ₂ removal efficiency is improved by flushing the rich solution 14 in the flash drum 27. Further, heat is exchanged by the semi-lean solution heat exchanger 29 interposed in the branched second rich solution supply pipe 20-2 by the residual heat of the semi-lean solution 28 from which the CO ₂ from the flash drum 27 has been removed. The temperature of the rich solution 14 introduced into the regenerator 15 can be raised, and as a result, the steam supply amount used in the regeneration tower 15 can be reduced. The semi-lean solution 28 from which CO ₂ has been partially removed by the flash drum 27 has most of the CO ₂ removed, so that it is supplied to the middle stage of the absorption tower 13 without being regenerated by the regeneration tower 15. CO ₂ is absorbed.
The CO ₂ removed by the flash drum 27 joins with the CO ₂ from the regeneration tower 15 and is collected separately.

  The division ratio of the rich solution 14 in the first rich solution supply pipe 20-1 and the second rich solution supply pipe 20-2 in the branch portion 24 is 30:70 to 70:30, preferably 50:50. do it.

In the present embodiment, the inside of the absorption tower 13 is further divided into two stages to form an upper packed bed 13-U and a lower packed bed 13-L, and the absorbing liquid that has absorbed CO ₂ from the upper packed bed 13-U to the outside. 12 is extracted and mixed with the semi-lean solution 28 to cool. This is because the absorption reaction is an endothermic reaction, so it is preferable to lower the temperature of the supplied liquid. In this embodiment, the temperature is lowered to about 40 to 50 ° C.

[Third Embodiment]
FIG. 3 is a schematic view of a CO ₂ recovery apparatus according to the third embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the first and second embodiments, a description thereof will be omitted given the same reference numerals.
As shown in FIG. 3, the CO ₂ recovery device according to the third embodiment of the present invention is a branch portion 24 provided in a rich solution supply pipe 20 that further branches the rich solution 14 in the first embodiment. A steam condensate heat exchanger 31 that is provided at the end of the branched first rich solution supply pipe 20-1 and flushes the rich solution 14, and is provided in the branched second rich solution supply pipe 20-2. A semi-lean solution heat exchanger 29 that heats the rich solution 14 with the residual heat of the semi-lean solution 28 from which CO ₂ has been partially removed by the steam condensate heat exchanger 31, and supplies the semi-lean solution 28. The end of the semi-millin solution supply pipe 30 is connected to the middle part of the absorption tower 13.

In the present embodiment, the steam condensate heat exchanger 31 is not an exchanger such as the plate heat exchanger described above, but a flash unit 32 for flushing the rich solution 14 as shown in FIG. A first flash drum 33 provided, a packed bed 34 provided in the flash drum 33, and a steam supply unit 36 provided at the lower part of the flash drum and supplying steam 35 from the steam condensed water 19 are configured. It will be.
When the steam condensate 19 is pressurized saturated steam, a second flash drum 37 is provided to form normal pressure steam, and the steam 35 is supplied to the first flash drum 33. CO ₂ is removed from the rich solution 14.
The semi-lean solution 28 from which a part of CO ₂ has been removed in the first flash drum 33 is used to heat the rich solution 14 in the semi-lean heat exchanger 29 using the remaining heat, and then supplied to the middle stage of the absorption tower 13. The

In the present embodiment, a steam condensate heat exchanger 31 is provided that heats the rich solution 14 in the branched first rich solution supply pipe 20-1 due to the residual heat of the steam condensate 19 from the regeneration heater 18. Since the rich solution is heated by the steam 35, the remaining heat of the steam condensate 19 used in the regenerative heater 18 is effectively used. The semi-lean solution 28 from which CO ₂ has been removed by flashing in the steam condensate heat exchanger 31 uses the remaining heat, and the semi-lean solution heat exchanger 29 interposed in the branched second rich solution supply pipe 20-2. Therefore, the temperature of the rich solution 14 introduced into the regeneration tower 15 can be raised, and as a result, the amount of steam supplied in the regeneration tower 15 can be reduced.
The CO ₂ removed by the first flash drum 33 joins with the CO ₂ from the regeneration tower 15 and is collected separately.
Note that the first flash drum 33 functions as a sub-regeneration tower with respect to the regeneration tower 14.

[Fourth Embodiment]
FIG. 4 is a schematic view of a CO ₂ recovery device according to the fourth embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the first to third embodiments, a description thereof will be omitted given the same reference numerals.
As shown in FIG. 4, the CO ₂ recovery device according to the fourth embodiment of the present invention is the same as that of the first embodiment, and the upper regeneration tower 15 is further divided into upper and lower parts. Steam condensing provided between the U and lower regeneration tower 15-L, the branch portion 24 provided in the rich solution supply pipe 20 for branching the rich solution 14, and the branched first rich solution supply pipe 20-1. The rich solution 14 is heated by the residual heat of the semi-lean solution 28 which is provided in the water heat exchanger 21 and the branched second rich solution supply pipe 20-2 and partially removes CO ₂ in the upper regeneration tower 15-U. The end of the first rich solution supply pipe 20-1 is connected to the lower regeneration tower 15-L, and the end of the second rich solution supply pipe 20-2 is provided. When the section is connected to the upper regeneration tower 15-U, In addition, the end of the semi-lean solution supply pipe 30 for supplying the semi-lean solution 28 is connected to the middle stage portion of the absorption tower 13.

In the present embodiment, the steam condensed water heat exchanger 21 that heats the rich solution 14 by the residual heat of the steam condensed water 19 from the regeneration heater 18 is provided, and the rich solution is heated by the residual heat of the steam condensed water. The remaining heat of the steam condensate 19 used in the regenerative heater 18 is effectively used. Further, the rich solution 14 that has obtained the residual heat is introduced into the lower regeneration tower 15-L, where it is regenerated.
The semi-lean solution 28 from which a part of CO ₂ in the rich solution 14 has been removed by the upper regeneration tower 15-U is taken out to the outside through the semi-lean supply pipe 30 and branched into the second rich solution supply pipe 20 branched by the residual heat. -2, the temperature of the rich solution 14 to be introduced into the regeneration tower 15 can be raised, and as a result, the steam supply amount used in the regeneration tower 15 is reduced. can do.

  The dividing ratio of the rich solution 14 in the first rich solution supply pipe 20-1 and the second rich solution supply pipe 20-2 in the branch portion 24 may be 25:75 to 75:25.

[Fifth Embodiment]
FIG. 5 is a schematic view of a CO ₂ recovery device according to the fifth embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the first to fourth embodiments, a description thereof will be omitted given the same reference numerals.
As shown in FIG. 5, the CO ₂ recovery apparatus according to the fifth embodiment of the present invention includes an upper regeneration tower 15 -U, a middle regeneration tower 15-, in which the regeneration tower 15 is divided into upper, middle, and lower parts. M and the lower regeneration tower 15-L, the branch portion 24 provided in the rich solution supply pipe 20 for branching the rich solution 14, and the lean solution heat interposed in the branched first rich solution supply pipe 20-1. A semi-lean solution which is provided in the exchanger 23 and the branched second rich solution supply pipe 20-2 and heats the rich solution with the residual heat of the semi-lean solution 28 from which CO ₂ has been partially removed by the upper regeneration tower 15-U. The heat exchanger 29 and the semi-lean solution 28 from which CO ₂ has been partially removed by the middle regenerator 15 -M are extracted to the outside of the regenerator through the extraction tube 41, and the steam condensation that heats the semi-lean solution 28 with the residual heat of the steam condensate 19. Hydrothermal exchange And the end of the first rich solution supply pipe 20-1 is connected to the middle regeneration tower 15-M, and the end of the second rich solution supply pipe 20-2 is the upper regeneration. The extraction pipe 41 is connected to the lower regeneration tower 15-L, and the end of the supply pipe 30 for supplying the semi-lean solution 28 is connected to the middle part of the absorption tower 13. It will be.

In the present embodiment, the steam condensate heat exchanger 21 that heats the semi-lean solution 28 extracted by the extraction pipe 41 is provided, and the semi-lean solution 28 is heated by the residual heat of the steam condensate 19, so that the regeneration heater The remaining heat of the steam condensate 19 used in 18 is effectively used, and as a result, the amount of steam supplied in the regeneration tower 15 can be reduced.
Further, the lean solution 16 regenerated in the regeneration tower 15 exchanges heat of the rich solution 14 in the lean solution heat exchanger 23 interposed in the branched first rich solution supply pipe 20-1, and this residual heat is removed. Since the obtained rich solution 14 is introduced into the middle regeneration tower 15-M, the steam supply amount used in the regeneration tower can be reduced.
The semi-lean solution 28 from which a part of CO ₂ in the rich solution 14 has been removed by the upper regeneration tower 15-U is taken out to the outside through the semi-lean supply pipe 30 and branched into the second rich solution supply pipe 20 branched by the residual heat. -2, the temperature of the rich solution 14 introduced into the upper regeneration tower 15 -U can be raised, and as a result, the steam supply used in the regeneration tower 15 is exchanged. The amount can be reduced.

  The dividing ratio of the rich solution 14 in the first rich solution supply pipe 20-1 and the second rich solution supply pipe 20-2 in the branch portion 24 may be 25:75 to 75:25.

[Sixth Embodiment]
FIG. 6 is a schematic view of a CO ₂ recovery apparatus according to the sixth embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the first to fifth embodiments, description thereof will be omitted with the same reference numerals.
As shown in FIG. 6, in the CO ₂ recovery apparatus according to the sixth embodiment of the present invention, the regeneration tower is divided into at least two parts, an upper regeneration tower 15-U and a lower regeneration tower 15-L. A steam condensate heat exchanger 21 that heats the semi-lean solution 28 from which CO ₂ partially removed from the upper regeneration tower 15-U through the extraction pipe 41 is heated by the residual heat of the steam condensate is provided. The semi-lean solution 28 is supplied to the lower regeneration tower 15-L.

  In the present embodiment, a steam condensate heat exchanger 21 for heating the semi-lean solution 28 extracted by the extraction pipe 41 due to the residual heat of the steam condensate 19 from the regeneration heater 18 is provided, and the residual heat of the steam condensate is provided. Since the semi-lean solution 28 is heated, the remaining heat of the steam condensate 19 used in the regeneration heater 18 is effectively used. As a result, the amount of steam supplied in the regeneration tower 15 can be reduced.

[Seventh Embodiment]
FIG. 7 is a schematic view of a CO ₂ recovery apparatus according to the seventh embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the first to sixth embodiments, and a description thereof will be omitted given the same reference numerals.
As shown in FIG. 7, the CO ₂ recovery device according to the seventh embodiment of the present invention is the first embodiment provided in the rich solution supply pipe 20 that branches the rich solution 14 in the device of the sixth embodiment. The first lean solution heat exchanger 23-1 interposed between the first rich solution supply pipe 20-1 branched at the first branch portion 24-1, The rich solution 14 is heated by the residual heat of the semi-lean solution 28 which is provided in the second rich solution supply pipe 20-2 branched by the branch portion 24-1 and partially removes CO2 in the upper regeneration tower 15-U. After the heat exchange in the semi-lean solution heat exchanger 29 and the semi-lean solution heat exchanger 29, the first rich solution supply pipe 20-1 and the second rich solution supply pipe 20-2 are joined together in the junction 42. Second lean solution heat exchanger for exchanging heat of rich liquid 14 3-2 and the second branch part 24-2 provided on the downstream side of the semi-lean solution heat exchanger 29 of the supply pipe 30 for supplying the semi-lean solution 28, and the second branch part 24-2. A steam condensate heat exchanger 21 interposed in the first semi-lean solution supply pipe 30-1, and the end of the first semi-lean solution supply pipe 30-1 is the lower regeneration tower 15-L. And the end of the second semi-lean solution supply pipe 30-2 branched at the second branch is connected to the middle stage of the absorption tower 13.

  In the present embodiment, the residual heat of the semi-lean solution 28 extracted from the upper regeneration tower 14-U is effectively utilized by heating the rich solution 14 in the semi-lean solution heat exchanger 29. Further, when a part of the semi-lean solution 28 is returned again to the lower regeneration tower 15-L via the first semi-lean solution supply pipe 30-1, a steam condensate heat exchanger 21 is provided. The semi-lean solution 28 can be heated by the residual heat of the steam condensate 19 and the residual heat of the steam condensate 19 used in the regeneration heater 18 is effectively used. As a result, the steam supply amount used in the regeneration tower 15 Can be reduced.

  The rich solution 14 is branched once and heat-exchanged by the semi-lean solution heat exchanger 29, and the other branched rich solution is also heat-exchanged by the first lean solution heat exchanger 23-1, and these rich solutions are exchanged. Are combined in the merging section 42 and further heat-exchanged in the second lean solution heat exchanger 23-2, and then supplied to the upper regeneration tower 15-U. Therefore, the rich solution introduced into the regeneration tower As a result, the steam supply amount used in the regeneration tower 15 can be reduced.

[Eighth Embodiment]
FIG. 8 is a schematic view of a CO ₂ recovery device according to the eighth embodiment.
Note that the first and second and third and fourth and fifth and sixth configurations with overlapping member of the CO ₂ recovery apparatus according to the embodiment, the description thereof will be denoted by the same reference numerals will be omitted .
As shown in FIG. 8, in the CO ₂ recovery apparatus according to the eighth embodiment of the present invention, the regeneration tower is divided into at least two parts, an upper regeneration tower 15-U and a lower regeneration tower 15-L. A semi-lean solution 28 from which the CO ₂ has been partially removed from the upper regeneration tower 15 -U is interposed in an extraction pipe 41, and the semi-lean solution 28 is heated by the residual heat of the lean solution 16 flowing in the lean solution supply pipe 22. 1, the lean solution heat exchanger 23-1 and the first lean solution heat exchanger 23-1 on the downstream side of the extraction pipe 41, and once heated, the semi-lean solution 28 is heated again with the steam condensate 19. And a second steam heat exchanger 23-2 that heats the rich solution 14 with the residual heat of the lean solution after heating the semi-lean solution 28. This is provided in the rich solution supply pipe 20.

  In the present embodiment, the semi-lean solution 28 extracted from the upper regeneration tower 15 -U is heated by the first lean solution heat exchanger 23-1 and further heated by the steam condensate water heat exchanger 21. The remaining heat of the steam condensate 19 used in the heater 18 is effectively used, and as a result, the amount of steam supplied in the regeneration tower 15 can be reduced.

  Further, the inside of the regeneration tower is divided into a plurality of stages, and while the semi-lean solution 28 extracted from each of the divided regeneration towers is returned to the regeneration tower on the lower stage side, a lean solution heat exchanger and a steam condensed water heat exchanger are installed. As a result, the temperature of the semi-lean solution 28 regenerated in the regeneration tower 15 can be raised, and as a result, the steam supply amount used in the regeneration tower 15 can be reduced.

[Ninth Embodiment]
FIG. 9 is a schematic view of a CO ₂ recovery device according to the ninth embodiment.
Note that the members overlapping with structure of the CO ₂ recovery apparatus according to the embodiment of the first to eighth, and a description thereof will be omitted given the same reference numerals.
As shown in FIG. 9, the CO ₂ recovery apparatus according to the eighth embodiment of the present invention includes an upper regeneration tower 15-U and a middle regeneration tower 15-, in which the regeneration tower 15 is divided into an upper part, a middle part, and a lower part. The semi-lean solution 28 from which a part of CO ₂ extracted from the M and lower regeneration tower 15-L and the upper regeneration tower 15-U through the first extraction pipe 41-1 has been partially removed is heated with the lean solution from the regeneration tower. The first lean solution heat exchanger 23-1 and the semi-lean solution 28 from which part of CO ₂ extracted from the central regeneration tower 15-M through the second extraction pipe 41-2 has been partially removed with steam condensed water. A steam condensate heat exchanger 21 for heating, a semi-lean solution heat exchanger 29 provided in the rich solution supply pipe 20 and for heating the rich solution 14 with a part of the semi-lean solution 28 extracted from the middle regeneration tower 15-M, , Rich solution A second lean solution heat exchanger 23-2 which is provided on the downstream side of the semi-lean solution heat exchanger 29 of the tube 20 and heats the rich solution 14 with the residual heat of the lean solution 16 after heating the semi-lean solution 28; The heated semi-lean solution is supplied to the lower side of the regeneration tower, and the semi-lean solution after the heat exchange in the semi-lean solution heat exchanger 29 is supplied via the semi-lean solution supply pipe 30 to the absorption tower 13. It is designed to be supplied to the middle part.

In the present embodiment, the semi-lean solution 28 extracted from each of the upper regeneration tower 15-U and the middle regeneration tower 15-M is heated by the first lean solution heat exchanger 23-1 or the steam condensed water heat exchanger 21. Thus, the residual heat of the lean solution 16 and the steam condensate 19 is effectively used, and as a result, the amount of steam supplied in the regeneration tower 15 can be reduced.
Further, the residual heat of the semi-lean solution 28 after heat exchange in the steam condensate heat exchanger 21 is used for heating the rich solution, and the residual heat of the lean solution heat-exchanged in the first lean solution heat exchanger 23-1 is used as the first heat. By using the lean solution heat exchanger 23-2 for heating the rich solution, the temperature of the rich solution 14 supplied to the regeneration tower 15 can be raised. As a result, the steam supply amount used in the regeneration tower 15 is reduced. Can be reduced.

  Hereinafter, although the suitable Example which shows the effect of this invention is described, this invention is not limited to this.

A CO ₂ recovery device according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 10 is a conceptual diagram illustrating the CO ₂ recovery device according to the first embodiment.
As shown in FIG. 10, the CO ₂ -containing exhaust gas 11 supplied to the CO ₂ absorption tower 13 is brought into countercurrent contact with the absorbent 12 having a predetermined concentration supplied from the nozzle 8 by the filling parts 25 a and 25 _b , and the combustion exhaust gas The CO ₂ contained therein is absorbed and removed by the CO ₂ absorbent 12 and the remaining CO ₂ -removed exhaust gas 10 from which CO ₂ has been absorbed and removed is sent to the outside. Absorbing liquid 12 to be supplied to the CO ₂ absorption tower 13 absorbs CO _2, heated to a high temperature than the temperature in conventional overhead for reaction heat by the absorption, by the absorption liquid discharge pump 51 that has absorbed CO _2, the rich solution 14 is sent to the lean solution heat exchanger 23 and the steam condensate heat exchanger 21, heated and guided to the regeneration tower 15.

In the regeneration tower 15, the absorption liquid is regenerated by heating by the regeneration heater 18 by the steam 17, and the CO ₂ absorption tower is cooled as the lean solution 16 by the lean solution heat exchanger 23 and the cooler 52 provided as necessary. Return to 13. In the upper part of regeneration tower 15, CO ₂ separated from the absorbing liquid is separated from the cooled by regeneration tower reflux condenser 53, reflux water vapor entrained by CO ₂ separator 54 CO ₂ is condensed, recovered CO sent from ₂ discharge line 55 to the outside of the system. The reflux water 56 is refluxed to the regeneration tower 15 by a reflux water pump 57.

In this embodiment, the steam used in the regenerative heater 18 is led to the CO ₂ separator 54 to be flashed, and the remaining heat is used as the steam condensate 19 in the steam condensate heat exchanger 21 for heating the rich solution. Yes.

  As a comparison, the case where the steam condensate heat exchanger 21 is not provided is shown in FIG.

When the temperature of the rich solution 14 discharged from the absorption tower 13 is 50.5 ° C., in the case of only the lean solution heat exchanger 23, the temperature was 114.2 ° C. Since the water heat exchanger 21 was provided, the temperature rose to 116.7 ° C., and as a result, the steam consumption in the regeneration tower 15 became 97.96 MMkcl / h.
In FIG. 10, the temperature (° C.) is enclosed by a square, the flow rate (t / h) is enclosed by a parallelogram, and the amount of heat (MMkcl / h) is indicated by parentheses. The same applies to FIGS. 11 to 21 below.

  Moreover, the steam consumption of the comparative example of FIG. 22 was 98.77 MMkcl / h. Assuming that the comparative example is 100, the rate is 99.2%, so the steam unit reduction rate (improvement effect) was 0.8%.

A CO ₂ recovery device according to a _second embodiment of the present invention will be described with reference to the drawings.
FIG. 11 is a conceptual diagram illustrating a CO ₂ recovery device according to the _second embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 2, the flash drum 61 is provided on the downstream side of the steam condensed water heat exchanger 21 that heats the rich solution 14. Since the rich solution 14 is heated by the steam condensate heat exchanger 21 on the front side of the flash drum 61, the flash drum 61 can remove CO ₂ in the rich solution 14.
Although the temperature of the rich solution from the flash drum 61 is 103.9 ° C., a part of CO ₂ is removed, so lowering the inlet temperature of the regeneration tower 15 causes water vapor to be taken out from the top of the tower. This is preferable.
In Example 2, the steam consumption in the regeneration tower 15 was 97.64 MMkcl / h as a result. Assuming that the comparative example is 100, it is 98.1%, and the steam unit reduction rate (improvement effect) was 1.1%.

A CO ₂ recovery device according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 12 is a conceptual diagram illustrating a CO ₂ recovery device according to the third embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In the third embodiment, a flash drum 61 is provided on the upstream side of the steam condensed water heat exchanger 21 that heats the rich solution 14. Since the rich solution 14 is heated by the steam condensed water heat exchanger 21 on the rear stage side of the flash drum 61, the temperature in the rich solution 14 supplied to the regeneration tower 15 is increased.
In Example 3, as a result, the steam consumption in the regeneration tower 15 was 97.27 MMkcl / h. When the comparative example is 100, it is 98.5%, so the steam consumption rate reduction rate (improvement effect) was 1.5%.

A CO ₂ recovery apparatus according to Embodiment 4 of the present invention will be described with reference to the drawings.
FIG. 13 is a conceptual diagram illustrating a CO ₂ recovery device according to a fourth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 4, the rich solution 14 is branched and a part thereof is sent to the flash drum type heat exchanger 31 where heat is exchanged with steam from the steam condensed water to remove CO ₂ in the rich solution 14. It was. Using the remaining heat of the semi-lean solution 28 after the heat exchange, the other rich solution 14 branched by the semi-lean solution heat exchanger 29 is subjected to heat exchange, and the temperature in the rich solution 14 supplied to the regeneration tower 15 is increased. .
In Example 4, as a result, the steam consumption in the regeneration tower 15 was 97.56 MMkcl / h. Assuming that the comparative example is 100, the rate is 98.8%, and the steam unit reduction rate (improvement effect) was 1.2%.

A CO ₂ recovery apparatus according to Embodiment 5 of the present invention will be described with reference to the drawings.
FIG. 14 is a conceptual diagram illustrating a CO ₂ recovery device according to the fifth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In the fifth embodiment, the rich solution 14 is branched, and a part of the rich solution 14 is sent to the flash drum type heat exchanger 31, and the steam condensate heat exchanger 21 exchanges heat with the remaining heat of the steam condensate 19 in the middle of the flash solution. In the drum 31, the removal efficiency of CO ₂ in the rich solution 14 was improved. Using the remaining heat of the semi-lean solution 28 after the heat exchange, the other rich solution 14 branched by the semi-lean solution heat exchanger 29 is subjected to heat exchange, and the temperature in the rich solution 14 supplied to the regeneration tower 15 is increased. .
In Example 5, the steam consumption in the regeneration tower 15 was 95.52 MMkcl / h as a result. When the comparative example is 100, it is 96.7%, and the steam unit reduction rate (improvement effect) was 3.3%.

A CO ₂ recovery device according to Embodiment 6 of the present invention will be described with reference to the drawings.
FIG. 15 is a conceptual diagram illustrating a CO ₂ recovery device according to a sixth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 6, the regeneration tower 15 is divided into two parts, the semi-lean solution 28 extracted from the upper regeneration tower 15-U is subjected to heat exchange with the residual heat of the steam condensate 19 by the steam condensate heat exchanger 21, and the lower regeneration tower 15- Returned to L. As a result, the temperature of the semi-lean solution supplied to the lower side of the regeneration tower 15 is increased.
In Example 6, as a result, the steam consumption in the regeneration tower 15 was 93.65 MMkcl / h. When the comparative example is 100, it is 94.8%, so the steam unit reduction rate (improvement effect) was 5.2%.

A CO ₂ recovery apparatus according to Embodiment 7 of the present invention will be described with reference to the drawings.
FIG. 16 is a conceptual diagram illustrating a CO ₂ recovery device according to a seventh embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 7, the regeneration tower is divided into two stages. Further, the rich solution 14 is branched, the lean solution heat exchanger 23 is provided in the branched first rich solution supply pipe 20-1, and the steam condensate heat exchanger 21 is provided on the downstream side, so that the lower regeneration tower 15 is provided. The temperature of the rich solution 14 to be supplied to is increased. In addition, the semi-lean solution heat exchanger 29 caused by the residual heat of the semi-lean solution 28 from the upper regeneration tower 15-U is provided in the branched second rich solution supply pipe 20-2, so that the rich supplied to the upper regeneration tower 15-U is provided. The temperature of the solution was raised.

The branching ratio was 70% for the first rich solution and 30% for the second rich solution.
In Example 7, the steam consumption in the regeneration tower 15 was 93.58 MMkcl / h as a result. When the comparative example is 100, it is 94.8%, so the steam unit reduction rate (improvement effect) was 5.2%.

A CO ₂ recovery device according to Example 8 of the present invention will be described with reference to the drawings.
FIG. 17 is a conceptual diagram illustrating a CO ₂ recovery device according to an eighth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 8, the regeneration tower 15 is divided into two parts, and the semi-lean solution 28 extracted from the upper regeneration tower 15-U is first subjected to heat exchange in the first lean solution heat exchanger 23-1, and then steam condensed water heat is used. Heat was exchanged with the residual heat of the steam condensate 19 by the exchanger 21, and returned to the lower regeneration tower 15-L. As a result, the temperature of the semi-lean solution supplied to the lower side of the regeneration tower 15 is increased.
In Example 8, as a result, the steam consumption in the regeneration tower 15 was 91.1 MMkcl / h. When the comparative example is 100, it is 92.3%, and the steam unit reduction rate (improvement effect) was 7.7%.

A CO ₂ recovery device according to Embodiment 9 of the present invention will be described with reference to the drawings.
FIG. 18 is a conceptual diagram illustrating a CO ₂ recovery device according to the ninth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 9, the regeneration tower 15 was divided into four to form a first regeneration tower 15-1, a second regeneration tower 15-2, a third regeneration tower 15-3, and a fourth regeneration tower 15-4. And the semi-lean solution 28 extracted from the 1st regeneration tower 15-1 and the 3rd regeneration tower 15-3 is the 1st steam condensed water heat exchanger 21-1 and the 2nd steam condensed water heat by the residual heat of steam condensed water, respectively. Heat was exchanged with the exchanger 21-2. Since the temperature on the lower side of the regeneration tower is high, the remaining heat of the steam condensate 19 was efficiently used.

The semi-lean solution extracted from the second regeneration tower 15-2 was heat-exchanged by the first lean solution heat exchanger 23-1 due to the residual heat of the lean solution 16. Further, the semi-lean solution 28 extracted from the first regeneration tower 15-1 is caused by the residual heat of the lean solution 16 exchanged by the first lean solution heat exchanger 23-1 before returning to the second regeneration tower 15-2 on the lower stage side. Heat was exchanged in the second lean solution heat exchanger 23-2 to be heat exchanged. In this example, after that, the rich solution 14 from the absorption tower was heat-exchanged by the third lean solution heat exchanger 23-3.
In Example 9, as a result, the steam consumption in the regeneration tower 15 was 85.49 MMkcl / h. When the comparative example is set to 100, it is 86.6%, so the steam unit reduction rate (improvement effect) was 13.4%.

A CO ₂ recovery device according to Embodiment 10 of the present invention will be described with reference to the drawings.
FIG. 19 is a conceptual diagram illustrating a CO ₂ recovery device according to the ninth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 10, the regeneration tower 15 was divided into three parts, ie, an upper regeneration tower 15-U, a middle regeneration tower 15-M, and a lower regeneration tower 15-L. Then, the semi-lean solution 28 extracted from the middle regeneration tower 15-M was subjected to heat exchange in the steam condensate heat exchanger 21 due to the residual heat of the steam condensate. Part of the extracted semi-lean solution 28 was supplied to a semi-lean solution heat exchanger 29 that heats the rich solution 14, and the remaining heat of the semi-lean solution was efficiently used.
The semi-lean solution extracted from the upper regeneration tower 15 -U was heat-exchanged by the first lean solution heat exchanger 23-1 due to the residual heat of the lean solution 16.
In addition, the rich solution 14 heat-exchanged by the semi-lean solution heat exchanger 29 is heat-exchanged by the residual heat of the lean solution 16 heat-exchanged by the first lean solution heat exchanger 23-1, and then the second lean solution heat exchanger 23- Heat exchange was carried out in 2.
In Example 9, as a result, the steam consumption in the regeneration tower 15 was 91.9 MMkcl / h. When the comparative example is 100, it is 93.0%, so the steam consumption rate reduction rate (improvement effect) was 7%.

A CO ₂ recovery device according to Embodiment 11 of the present invention will be described with reference to the drawings.
FIG. 20 is a conceptual diagram illustrating a CO ₂ recovery device according to the eleventh embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 11, the regeneration tower 15 was divided into two parts, ie, an upper regeneration tower 15-U and a lower regeneration tower 15-L. Then, the semi-lean solution 28 extracted from the upper regeneration tower 15-U heats the rich solution in the second rich solution supply pipe 20-2 branched by the semi-lean solution heat exchanger 29 and then branches it to regenerate the lower part. Before supplying to the tower 15-L, heat was exchanged by the steam condensed water heat exchanger 21 due to the residual heat of the steam condensed water.
Further, the rich solution in the first rich solution supply pipe 20-1 is heat-exchanged by the first lean solution heat exchanger 23-1, and then the rich solution is joined, and the second lean solution heat due to the residual heat of the lean solution 16. Heat was exchanged by the exchanger 23-2 and supplied to the regeneration tower 15.
In Example 11, as a result, the steam consumption in the regeneration tower 15 was 93.96 MMkcl / h. When the comparative example is 100, it is 95.1%, so the steam unit reduction rate (improvement effect) was 4.9%.

A CO ₂ recovery device according to Embodiment 12 of the present invention will be described with reference to the drawings.
FIG. 21 is a conceptual diagram illustrating a CO ₂ recovery device according to the twelfth embodiment. In addition, about the member similar to Example 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In Example 12, the regeneration tower 15 was divided into three parts, ie, an upper regeneration tower 15-U, a middle regeneration tower 15-M, and a lower regeneration tower 15-L. Then, the semi-lean solution 28 extracted from the middle regeneration tower 15-M was subjected to heat exchange in the steam condensate heat exchanger 21 due to the residual heat of the steam condensate.
Moreover, the rich solution 14 was divided | segmented and the lean solution heat exchanger 23 was provided in the 1st rich solution supply pipe | tube 20-1. Further, the second rich solution supply pipe 20-2 is subjected to heat exchange using a lean solution heat exchanger 29 using the semi-lean solution 28 extracted from the upper regeneration tower 15-U, and the residual heat of the semi-lean solution is efficiently obtained. Used.
In Example 12, as a result, the steam consumption in the regeneration tower 15 was 91.14 MMkcl / h. When the comparative example is 100, it is 92.3%, and the steam unit reduction rate (improvement effect) was 7.7%.

11 CO ₂ -containing gas 12 CO ₂ absorbent 13 Absorption tower 14 Rich solution 15 Regeneration tower 16 Lean solution 17 Steam 18 Regeneration heater 19 Steam condensed water 21 Steam condensed water heat exchanger 22 Lean solution supply pipe 23 Lean solution heat exchanger 8 Nozzle 9 Chimney tray 10 CO ₂ removal exhaust gas

Claims (6)

An absorption tower for CO ₂ is contacted with the gas and the CO ₂ absorbing liquid containing the removal of CO _2, and regeneration tower for reproducing rich solution that has absorbed CO _2, the lean solution obtained by removing CO ₂ in the regeneration tower A CO ₂ recovery device for reuse in an absorption tower,
The regeneration tower has a plurality of stages, an extraction pipe for extracting a semi-lean solution from which CO ₂ has been partially removed from the lower part of the upper regeneration tower and introducing it into the upper part of the lower regeneration tower;
A CO ₂ recovery apparatus comprising: a lean solution heat exchanger that is interposed in the extraction pipe and heats the semi-lean solution by residual heat of the lean solution. In claim 1,
A first lean solution heat exchanger interposed in the extraction pipe and heated by the residual heat of the lean solution;
The semi-lean solution the CO ₂ recovery apparatus characterized by being provided with the second lean-solution heat exchanger for heating the rich solution, the residual heat of the lean solution after heating the. In claim 1 or 2,
A CO ₂ recovery device comprising a steam condensate heat exchanger interposed in the extraction pipe and exchanging heat of the semi-lean solution with steam condensate. In claim 1 or 2,
The regeneration tower is divided into an upper regeneration tower, a middle regeneration tower, and a lower regeneration tower, which are divided into upper, middle and lower parts,
A first extraction pipe for extracting a semi-lean solution from which CO ₂ has been partially removed from the lower part of the upper regeneration tower and introducing it into the upper part of the middle regeneration tower;
A first lean solution heat exchanger interposed in the extraction pipe and heated by the residual heat of the lean solution;
A _second extraction pipe for extracting a semi-lean solution from which CO ₂ has been partially removed from the lower part of the middle regeneration tower and introducing it into the upper part of the lower regeneration tower;
A steam condensate heat exchanger interposed in the second extraction pipe for exchanging heat of the semi-lean solution with steam condensate;
A CO ₂ recovery apparatus, comprising: a semi-lean solution supply pipe branched from the second extraction pipe and supplying a semi-lean solution to the middle stage of the absorption tower. The gas and the CO ₂ absorbing liquid containing CO ₂ is contacted in absorption column after removal of the CO _2, it reproduces the rich solution that has absorbed the CO ₂ in the regeneration tower to remove subsequently regenerated CO ₂ A CO ₂ recovery method for reusing a lean solution in an absorption tower,
The regeneration tower has a plurality of stages, and from the lower part of the upper regeneration tower, a semi-lean solution from which CO ₂ has been partially removed is extracted by an extraction pipe, introduced into the upper part of the lower regeneration tower,
A CO ₂ recovery method, wherein the semi-lean solution extracted by the extraction tube is heated by residual heat of the lean solution. In claim 5,
The semi-lean solution extracted by the extraction pipe is heated by the first lean solution heat exchanger by the residual heat of the lean solution,
A CO ₂ recovery method, wherein the rich solution 14 is heated by a second lean solution heat exchanger by the residual heat of the lean solution after the semi-lean solution is heated.

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